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Initials used as an abbreviation for the
American Society for Testing and Materials
. An organization devoted to the
establishment of standard methods and procedures of testing materials. Copies
of the approved test methods for urethane
may be secured by supplying
the identifying code number of the test plus the fee.
Normally used in the chemical sense of being a substance
used to increase the rate of a chemical reaction, often used synonymously with
the term catalyst
, or tin
In normal foam
practice, it is required that the chemicals used be weighed, pumped and dispensed
within plus or minus 0.5% of the correct amount. Capability of operation within
these narrow limits is available from most machine suppliers. See also 'metering
' and 'shot accuracy
The value given to trace residues of acids in the finished
. It is of interest because acids
can react directly with NCO
and thus must be allowed for in formulation
calculations (see index
). The normal value
for most polyether
polyols is less
than .05 parts per hundred. Most polyester polyols normally have an acid
between 0.1 and 0.5.
Small mechanical parts that assist the joining of 2 dissimilar
pieces, normally used to join pipes of different sizes or to assist in joining
pipe to hose threads. Pipe threads are normally tapered while hose threads are
A term used by liquid spreading device (reciprocator
manufacturers to describe the ability of machines to vary the height of the
mixer discharge nozzle
above the conveyor
(or mold) by raising or lowering the crossbar or rails on which the mixer is
riding. The adjustability may range from manually loosening bolts and lifting
the crossbar into position up to automatic push button operation. Hand powered
cranks turning built-in lifting screws are used for an intermediate type.
A term used by machinery manufacturers to describe the
ability of their pumps and mixers to be driven at different rates of speed.
The minimum type covered by this somewhat all-inclusive term is a set screw
adjusted split sheave (pulley). Other types range in complexity from manually
rotated cranks or hand wheels up to automatic push button adjustment. Not all
adjustable speeds are positive; thus some are not able to hold a setting after
adjustment and others are not able to reset at the same markings in order to
repeat the desired speed of rotation.
) a term used to refer
to the period of time after all accelerated curing attempts have ceased during
which maximum final physical properties are attained. Temperatures are usually
maintained at 70-75° F during this period. Example: a molded flexible cushion
may be pre-cured for 10 minutes at 250° F to develop enough properties to permit
removal from the mold, then post-cured for 1/2 to 3 hours to reach 85% to 95%
of the final properties, and then packaged and shipped during which time 'after-cure
continues until 100% of the properties are achieved. After-cure
generally is not longer than 3 to 6 days with most formulations
A term which describes material dripped from the discharge
orifice of a self-cleaning mixing head after the continuous flow
of liquid has ceased. It is usually objectionable and is influenced by mixer
design, mixer wear, mixer cleanliness, material viscosity
and flow characteristics, and leakage from the liquid delivery passages (metering
). agitators-a term which usually refers to the mechanisms that mix
and recirculate the various liquids within their tanks. These may be propellers,
paddles, turbines, etc. Occasionally the term is used to describe the rotor
that mixes the liquids
together in the final mixing chamber
just prior to foaming.
A term which refers to the practice of injecting very
small amounts of compressed air (or other gas) into the mixing
or into the polyol stream
prior to the mixing chamber in order to decrease the average cell
diameter in the foam. A high degree of control over cell diameter can be achieved
with a precision regulated air bleed system. See also 'catalyst
air bleed adapter
Air Metering Device
Method of atomizing a liquid stream
for spray application
using compressed air at the spray nozzle
and surface rebound are
(See also Aromatic
one of the main divisions of organic compounds (those containing carbon) and
particularly indicates those compounds having ab open chain molecular structure.
An ambiguous term usually coupled with temperature and
refers to the normal temperature of the particular room or environment in which
producing equipment or process
is installed. It is often used to indicate U.S.A. house or factory temperatures
of approximately 70° F.
A term which refers to a class of catalyst
compounds used in the urethane
reaction, These are
characterized by having N or NH groups in the molecule and generally accelerate
the 'blowing reaction' in preference to the 'gelling
'. The amines used as foam catalysts usually (but not necessarily)
have a distinctive odor, and are miscible with water.
An analysis value determined for isocyanate
materials to express their reactive strength, used in some methods for calculating
balance' of a
. The value secured has an inverse
relationship to the strength of the chemical as the larger the value, the weaker
is the reactive strength of the isocyanate per unit of weight. For example,
equivalent value for pure TDI
is approximately 87 while that of the less reactive crude 'polymeric
' may be over 130. The method of analysis may be obtained by
request to one of the major chemical companies supplying the isocyanate.
Angle of Foam Rise
A term which refers to the angle formed between the rising
front and the moving surface from
which it is rising on a continuous
process. This is usually critical for a given formula
with an excessively large angle tending to cause cracking of the foam block
while too low an angle tends to cause excessive settling
and splits. Adjustments to conveyor speed, chemical flow rate or conveyor angle
are usually helpful. Under extreme conditions, the catalyst
balance’ of the formulation
processing temperature may have to be modified.
Is used to describe foam
having different properties when tested along axes in different directions,
e. g. parallel to foam rise as opposed to perpendicular to the foam rise. This
difference occurs under conditions causing the individual bubbles to elongate
in the direction of foam rise, creating a strong columnar structure parallel
to foam rise and a weaker cylindrical structure perpendicular to the foam rise.
Materials which when added to a foam
improve the resistance
of the foam to oxidative type reactions. Some of these materials retard the
yellowing of flexible foam; some improve the aging characteristics of the final
foam product under both dry and humid high heat conditions.
Chemicals which impart a slight to moderate degree of
electrical conductivity to plastic
thus preventing the accumulation of electrostatic charges on finished articles.
They may be incorporated in the materials before molding
or applied to their surfaces after molding. They function either by being inherently
conductive or by absorbing moisture from the air. Examples of antistatic additives
are long-chain aliphatic amines
and amides, phosphate esters, quaternary ammonium salts, polyethylene glycols
polyethylene glycol esters, and ethoxylated long-chain aliphatic amines.
A term sometimes used as a noun in describing the practical
use of a particular formulation
or piece of equipment. The use of urethane
is often described in a manner such
as 'an insulating application
a 'spray-in-place application'.
A term used to describe an individual or company specializing
in the application
to a surface or structure. It is often used to describe those who apply foam
by spraying and thus are called 'spray applicators'.
A term which refers to a class of organic chemical compounds
characterized by having a benzene ring type molecular structure. Tolylene diisocyanate
is an example of this type chemical but other isocyanates
may or may not be. See also aliphatic
The accelerated testing of plastics
to determine their changes in properties such as dimensional
, water resistance, resistance to chemical and solvents
light stability, and fatigue resistance.
A term used to describe a control system on a metering
unit in which a pressure surge
in the fluid circuit is sensed, actuating a relay which turns off the pump drive
motor. This is an excellent safety-feature and does not affect the positive
value of the system.
A term used to describe a solvent
cleaning system for a urethane foam
mixing and dispensing head. The usual system is activated by a push button which
begins a cycle consisting of a timed amount of solvent, dispensed by a pressure
pot or pump, injected into the solvent
hose and then followed by a timed dispensing of compressed air blowing
the solvent from the hose line into the mixing
and from there to the waste container. Both solvent and air timers
can usually be adjusted to obtain optimum cleaning with maximum economy. A newer
system termed 'fully automatic solvent flush' includes an additional timer which
initiates the solvent cycle automatically if pouring has not occurred during
a preset time period.
A chair cushion that forms the back of the unit and is
characterized by being leaned on rather than sat on. Generally a lower density
is used for a Back
than is used for a 'seat
The higher upstream pressure developed by a restrictive
valve or regulator
Ball Rebound Test
One of several test methods for comparing various flexible
samples for resilience (see Resilience
). A steel ball of specified mass is dropped from a fixed height onto
sample, and the height of the rebound
of the ball is recorded. The rebound height is divided by the original height
to give a percentage. The method is a relative test rather than absolute, since
of the foam
has a strong influence on the results. The Test Method is described in ASTM
A term used to describe a clear or pigmented coating
sprayed into a mold prior to foaming, which adheres to the foam
and provides a base for further finishing steps. Usually used for rigid foam
finished to resemble wood.
A term which describes a type of mixer in which the entire
amount of the formula
required is poured
or pumped into the mixing head and mixed for a definite period of time with
multiple recirculation of the material through the mixing
. The entire amount of the material is poured out of the mixing head
at the conclusion of the mixing time period.
The process of simultaneously mixing the entire amount
of the formula
required in one container.
A term normally used to describe the polyol
or other premix tanks
used in the
slab process. In this process
some of the ingredients required are premixed
in a Batch Tank
in order to cut down
on the number of components
to be metered into the final mixer or to eliminate the problems involved with
very tiny amounts of materials
into a continuously mixed stream
called 'machine tanks
' to differentiate
them from 'in-plant storage tanks'.
A type of conveyor in which the conveying is performed
by means of the movement of the top surface of the structure as a continuous
ribbon or belt. The belt surfaces normally used in the urethane
industry are metal, cloth or rubber.
The commonest construction used in the flexible foam
slab process is probably that of the interlocked metal belt.
A term which refers to the type heating device that is
wrapped around a chemical tank to provide heat by conduction through the tank
walls. Some of these heaters are equipped with variable thermostats; some are
not. They are often used to supplement the in-line heaters when the chemical
to be pumped has a high viscosity
creating a cavitation problem if not warmed.
A term used to describe a cut-off segment of the continuously
of flexible or rigid foam
being made by the slab' technique. In some cases this Block
would have top, bottom, and side skins
intact and have cut surfaces only on the ends. In other cases the top, bottom
and side skins
may be removed by in-line
trimmers leaving a smooth rectangular Block
The chemical ingredient in the formulation
that provides the gas creating the expansion of the foam. This can be either
a low boiling
that vaporizes from the heat of the reaction such as fluorocarbon 11 or a chemical
such as water that reacts with the isocyanate
material to produce carbon dioxide. The low boiling
chemical type formulation
is usually referred to as 'solvent
', while the other type is commonly referred to as 'water
'. blowing reaction-one of the several chemical reactions occurring
in the final mixture while it is foaming. It is most often used to refer to
the chemical reaction resulting in the release of carbon dioxide.
Cavities that occur in the interior of the continuous
slab as it is produced. Some of these
cavities reach all the way to the top surface of the Block
and can be seen ejecting little clouds of vapor just past the peak
. See flaps
A standard of measurement in the foam
and construction industry which refers to a square foot of material one inch
in thickness. See super foot
A descriptive term applied to foam
that feels stiff and not flexible and yet is still in the flexible category.
A typical foam
of this type
would require a small amount of force to cause an initial deflection in the
and very little more
force to deflect it to 50% or more of its thickness, and then a straight line
increase in force is required for further deflection. See IFD
Sometimes used to describe the flat sheets of rigid or
cut from Blocks
of foam. However, recently the term has been specifically applied to the product
of a Continuous Lamination
Line on which the foam
is sandwiched between
Is a phenomenon that occurs when the gas being generated
is not trapped in the liquid resin
make foam. It occurs usually if the surface
have been omitted or are defective, or if gelation is not
occurring rapidly enough in relation to the speed of the blowing reaction.
A specially shaped Back
, usually for Danish modern style couches or divans. The normal shape
is a truncated wedge, although round, rectangular, and triangular are also available.
The term is also used to describe a cylindrical, stiff pillow
used for decorative purposes on a bed.
A synonym for gluing, adhering, laminating or rebonding.
A slang term referring to the pattern of high density
streaks or flow
lines that occur on the
bottom of a foam Block
of the rising
front occurs, or when shearing movements
occur in the rising foam
A mechanical device for drilling a long straight hole
through a Block
in order to insert the mandrel used in 'log
A term used in slightly different ways by many people
but ordinarily refers to the presence of a scattering of cells
2 to 4 times larger than the uniform background cell
diameter. If a thin section of the foam
were cut from the Block
, it would look
as if a shotgun had blasted it with buckshot.
usually a very alkaline Amine
, that has
been partially or wholly neutralized with acid so that the reaction would not
be affected by the extreme alkalinity of the catalyst
The general effect of the buffering is to slow the rate of the polymerization
Chemicals added to the formula
that decrease the sensitivity of the formula
to slight changes in the alkalinity or acidity of any of the components
. They are also known as buffering agents.
A material or chemical added to another chemical that
increases the quantity of the mixture required without changing the chemical
reactivity of the total. The term is not only used to describe solid or powdered
, but is also used to refer
to liquid Additives
. An example is
the bulking or dilution of the tin catalyst
that is often used to gain greater control over the metering
of very small quantities. In this case the tin catalyst
is often diluted or bulked-up with a portion of the polyol
Barium sulfate is a solid bulking agent
often added to the polyol
of the final foam
A series of tanks large enough in capacity that bulk
shipments of one or more of the ingredients used in the formulation
can be unloaded and stored directly on the premises. Also called 'in plant storage'.
Another synonym for Block
A term used to describe what happens when a puff of gas
is released during the formation of blows
The common abbreviation for the cubic
of the metric system. For liquid measurement the abbreviation
ml (milliliter is often used in place of cc. The two measurements are approximately
A common abbreviation for Compression-Deflection curve.
An abbreviation for cubic feet per minute.
The abbreviation for cycles per second. A recent international
decision suggests the use of HERZ instead of CPS with reference to electrical
wave motions. CPS is satisfactory for mechanical cycles.
The chemical symbol for carbon dioxide.
CO2 Blown Foam
Foam in which all of the gas for expanding or blowing
is carbon dioxide, generated by the chemical reaction between water and the
material. This type foam
is called 'water blown foam
A synonym for metering
referring to the weighing of carefully timed amounts of chemicals from the dispensing
ports of the mixing head in order to set an exact ratio of flow rates between
or to set an exact
A term used to describe the filling of small molds with
liquid, nonfoaming formulations
or other types of polymers
sometimes called solid elastomers
or casting resins
. Occasionally used to
describe the potting
or mechanical parts in foam.
Castor Oil Based
Foam made from a formula
in which the major polyol
is derived from castor oil.
Technically, a chemical that has the property of being
able to change the speed of a chemical reaction without apparently taking part
in the reaction. Most of the so-called catalysts
form reactions do have
some part in the reaction and consequently do not fall under the proper definition,
although they are often referred to by that name. (See Accelerator
Air Bleed Adapter
A device used to surround a catalyst
tube with a compressed air
in order to prevent unwanted accumulation
around the port that could interfere
with the flow
of the liquid.
A shortened form for catalyst
mixture. Most formulations
delicate balancing between the blowing and gelation reactions, and consequently
blends of different types of catalysts
are often used together with an inert carrier or diluent
to aid in metering accuracy
or in miscibility.
Is synonymous with bubble or pore. It refers to the cavities
left in the foam
structure after the bubble
walls have completely polymerized and solidified or curled back and fused into
the boundary joints to form a skeletal structure. Cells can be closed (intact
walls) or open (skeletal ribs only). Cell shape is more like an irregular polygon
than a globe.
The number of cells
or bubbles per linear inch or per centimeter. Cell count is very important to
the physical properties of foam. See cell size.
A term which refers to the average diameter of the pores
(bubbles) in the filial foam product. Although often still referred to as fine,
medium or coarse, or by the diameter in microns, most workers refer to the number
of cells per linear inch (cell count
(See cell size
A term often used to point out overall uniformity of foam
diameter. Example, 'uniform cell structure'
with generally equal cell
Cellular Plastic (Expanded
Plastic, Foamed Plastic)
with numerous cells
throughout its mass. The terms cellular, expanded, and foamed plastic
are used synonymously. A cellular plastic
may be produced by (1) incorporating a blowing
which decomposes to liberate a gas; (2) mechanically stirring in a
fluid or gas; (3) adding a water soluble salt or a solvent
extractible agent to the mix prior to foaming then leaching out the agent after
foaming to leave voids; or (4) other techniques.
1/100th of a poise
commonly used in describing the viscosities of the various chemical components
are less than 2000 centipoise, some individual components
may have viscosities as high as 100,000 to 200,000 centipoise. See poise
Is the lengthening of the spine or main chain of polymer
molecules by end to end attachment usually involving condensation of functional
groups between two or more molecules during the chemical (polymerization) reaction.
, a side to side attachment
of molecules, also occurs during polymerization. Some physical properties are
enhanced more by chain extension, others by cross
A small scale or narrow undercutting
of the expanding or rising foam
of the mixed clear liquid. This
is usually due to wrinkles in the paper or uneven distribution of the liquid.
Channeling often results in high density
on the bottom of the foam
referred to by some as bones
and others as striations
lines. Occasionally the term is used to refer to the condition arising when
a heated portion of a viscous
is recirculated back into a tank without agitation, flowing immediately to the
inlet of the pump without mixing with the cooler liquid.
A term occasionally used to describe the process of filling
the machine tanks
with the various
quantities of chemicals.
The disks and flanges used to separate the foam
ingredients from the operating mechanism, usually of a pressure
. The interior of the bourdon tube or bellows is filled, under vacuum
conditions, with an inert fluid, up to the back side of the metal disk or diaphragm.
This combination of liquid and membrane effectively isolates the mechanism without
A heat exchanger used for cooling the chemical materials.
Scraped surface, tube and shell, and plate type exchangers are all used, with
the scraped surface being the most efficient, particularly with the higher viscosity
A heat exchanger used for cooling the material but including
the cooling source. It usually consists of a scraped surface, tube and shell,
or plate type heat exchanger plus a refrigeration compressor and controls. The
package unit may be a direct expansion type in which the refrigerant expands
directly into the main heat exchanger or it may be of the liquid transfer type
in which the refrigerant gas expands into an intermediate heat exchanger, and
then a circulating liquid is used to conduct the heat from the main heat exchanger.
See cooling media
Type Chemical Seal
A special type chemical seal permitting cleaning of the
chemicals side of the disk without complete disassembly. See chemical seal.
Foam that recovers 100% from the pinching effects of
The process of stamping out irregular shaped articles
from thin sheets of foam
by means of a
hammering mechanism and a steel-rule die. See die
Is the property of a foam
of having each individual bubble completely sealed off from its neighbor so
that no exchange of gas can take place except by diffusion through the walls,
With rigid foams
, it is usual to
try for 100% closed cells to achieve maximum thermal insulating ability and
minimum water pickup. With flexible foams, it is normal to try for 100% open
for maximum flexibility, resilience, and breathability even to the
extent of achieving a true skeletal foam
in which even the broken membranes between cells
have been removed or fused back into the ribs."
The practice of molding
object in a cavity in which the
foaming liquid is 100% contained with only gas being allowed to escape.
Very large bubbles averaging not over 20 to 30 cells
per lineal inch. See cell size
The process of flexible foam
in which the molds are maintained
at temperatures between approximately 100° F and 150° F as compared with the
alternate "one shot
technique in which temperatures of 250° F to 350° F are obtained within one
minute of pouring. Flexible prepolymer
normally has utilized temperatures
in the "cold molding" range.
The sudden or complete loss of height occurring after
has partially or completely expanded.
Under extreme conditions, the foaming chemical mixture may not expand at all
but may merely boil violently and then harden into a solid sheet. See boiling
A dye or pigment used to color the foam
for appearance, identification, or for other sales purposes. Occasionally a
necessary minor ingredient may act as a colorant.
A term normally used by those interested in continuous
processing and referring to all of the equipment required to make a
product. This comprehensive list generally includes the paper handling equipment,
chemical handling equipment, the foam
the conveyors, the spreading or traversing device, curing devices or ovens,
cutting equipment and packaging equipment. Testing equipment and technical service
may or may not be included.
A term used to describe a separately metered stream
of liquid that will be directly introduced into the mixing head for the final
mixing. Although as many as 11 or more chemical components may be used in a
may be preblended into as few as two components for the final formulation
used in the machine. See number
Load Deflection (CLD)
The determination of the resistance to compression of
sample when the entire area of the
sample is compressed. This Test Method is described in ASTM
An industry expression used to describe the recovery
from static or fixed compression.
Less than 10% compression set (which is greater than 90% recovery) is usually
accepted as good. Also called 'percent set.' This Test Method is described in
A term primarily used to describe the resistance of rigid
to compression. This test method is
described in ASTM
Head (Continuous Mixer)
A mixing device capable of dispensing homogeneously mixed
material continuously, without affecting the temperature or pressure of the
mixture by virtue of its continuous operation. The individual components
may be valved as in the 'on-off'
, but are not required to be. Instantaneous start and/or stop
of all components
is not essential,
The production of a continuous, homogeneous, seamless
or other foam by laying down a uniformly distributed liquid film of mixed materials
on a conveyor belt
the mixing head at such a rate of speed as to form a stable rising front of
foam. The process may only last for a few minutes, or it may run for 24 hours
per day depending on sales requirements.
A method of foam
production in which the mixed material being discharged from the mixing head
is a clear liquid. This term is used to differentiate between non- frothed (conventional)
and frothed systems of production.
A term which refers to the process of cutting and shaping
used to convert bread loaf
into saleable items.
An endless loop of material, either metal, cloth, rubber,
or paper, used to carry the expanding foam
mixture in the manufacture of continuous
foam. The types are usually further described as 'linked metal', 'slat
type metal', 'rubber' (even when fabric reinforced), 'cloth', 'cotton', or 'canvas
The splitting of a sheet of flexible foam
while it is variably compressed so that two matching pieces of foam
are created, each with alternating patterns of hills and hollows on their adjacent
sides. The main advantages are that the foam
can be made softer and more resilient mechanically and that two pieces of foam
are produced, each of which is almost as thick as the original piece.
The material that carries the heat away from the chemicals.
In the direct expansion type of heat exchanger, the refrigerant gas is the cooling
medium; in the liquid transfer or 'brine' cooled type of heat exchanger, the
‘brine' is the cooling medium for the chemicals and the refrigerant gas is the
cooling medium for the 'brine'. In most modern cases, a solution of ethylene
permanent anti-freeze is used
for the 'brine' solution rather than the salt solution. See chiller
at the center of the foam
object. In most cases, foam
will form a
gradient in an object with the
being at the outer or
surfaces and the lowest density
being in the center or core of the object.
Long narrow openings or cavities in the foam
that have widely separated and relatively
smooth sides. These are subdivided into side
, top cracks
(internal cracks) for trouble shooting purposes. See the specific
headings for more detailed descriptions.
The condition in which the top surface of the continuous
resembles a photograph
of the surface of the moon. It is normally caused by entrapment of very large
gas bubbles that may have originated in the mixer or developed from excessive
lay down splashing
or possibly liquid
the foam front.
Globules which may pop to the surface of the foam
front under certain conditions of flexible slab foam
manufacture. The balls may race madly down the slope of the rising foam
front or dash erratically around on the surface or just beneath the surface
of the rising foam.
The point on a continuous foam
slab conveyor where the clear mixed liquid becomes cloudy and begins to expand.
are present, they extend
upstream from the cream line into the clear material. When all variables have
been stabilized during a production run, the cream line will remain at a fixed
distance downstream from the mixing head.
A time interval defined somewhat differently between
a laboratory batch or hand mix and a production machine mixer. The laboratory
or batch type mixing definition is usually 'the time between the start of the
final mixing and the point at which the clear mixture turns creamy or cloudy
and starts to expand'. With the machine mixing process the cream time is generally
taken to be 'the time between the first material being poured until that material
turns creamy or cloudy'. Occasional misunderstandings arise over this and over
the occasional practice of labeling the time between final mixing and the start
of creaming or foaming as 'cream time' for laboratory or Batch
when it could more properly he termed 'liquid handling time'. The
problem results from the fact that laboratory type mixing requires as much as
100 times more mixing time than machine mixing. "Frothing" masks the
cream time but usually extends the overall 'handling
The dimensional change with time of a material under
load, following the initial instantaneous elastic deformation, Creep at room
temperature is sometimes called Cold Flow.
Applied to polymer
molecules, the setting-up of chemical links between the molecular chains. When
extensive, as in most thermosetting
, cross-linking makes one infusible
super-molecule of all the chains.
A term used by the furniture industry to describe a mattress
or cushion that is thicker in the middle than it is at any edge. This is much
easier to achieve with molded articles but can be achieved for slab produced
articles with the use of special cutting or abrading machines.
Is a term sometimes used to describe an undistilled isocyanate
mixture containing several different polymeric isocyanates
These mixtures are ordinarily a dark brown in color as opposed to the clear
water white color of distilled TDP. Some chemical manufactures object to the
description 'crude' and consequently many prefer the term 'polymeric' isocyanate
or 'undistilled' isocyanate
A common metric measure of volume developed from lineal
measurement. There are approximately 16.4 cubic centimeters in a cubic inch.
The liter is a preferred volumetric measurement, particularly liquids. One milliliter
(ml) is approximately equal to 1cc.
A common measure of volume in the English System. This
is a cube with length, width and height all equal to 1 foot. There are 1,728
cubic inches in a cubic foot. See cubic
A common measure of volume in the metric system developed
from lineal measurement. This is a cube with length, width, and height all equal
to 1 meter. Since there are 100 centimeters in a meter, there would be 1 million
cc’s in a cubic meter. There are approximately 35.3 cubic feet in a cubic meter.
A meter is approximately 39.4 inches in length.
A term which refers to the completeness of the chemical
reaction. At 100% completion, the foam
should have 100% of the maximum physical properties attainable with that particular
used. Because 100% cure
is not always reached in a practical length of time, some arbitrary time- temperature
period is usually assigned to a particular formula
to designate a practical level of cure at which testing for physical properties
may be started. See cure time
The final oven into which foam
articles are placed in order to achieve the desired final level of accelerated
cure. The term is sometimes ambiguous in normal use and is usually qualified
with a prefix or another word to make it more specific, such as pre-cure or
Curtain Wall Panel
Any type of panel that is hung on the outside of a building
to form the exterior skin
of the building, without bearing any structural load other than that which itself
with a foam
are often used in this type application
A special type of foam
cutting saw that is used to make vertical cuts. The traveling
is used to make cuts on a continuous
line in a direction across or perpendicular to the direction of foam
movement, while the foam
is moving. The
stationary cut-off saw is used to cut long slabs into shorter slabs while the
slab is stationary. This type of cutter
is normally a special band saw, having the blades twisted 90" from the plane
of the wheel surfaces in order to avoid interference problems with the saw wheels
or the other portion of the blade. Another version of this type saw is based
on the vibrating bayonet type of blade.
A slang expression generally meaning either Batch
or machine tanks
for one day’s production run. The tanks may not have to be very large as a 'daily'
production run may be only 20 minutes long for some factories.
Small, variously shaped pillows, usually with bright
colors, that are thrown onto chairs and sofas for color accent or general decoration.
Also called throw pillows
The number of structural units or mers in the 'average'
molecule in a particular sample.
In most plastics
the DP must reach several
thousand if worthwhile physical properties are to be had.
The time between pouring the liquid into the mold and
the removal of the foamed article from the mold. This is usually kept to the
minimum possible time in which the partially cured object can be handled without
damage, since it is more economical to reuse the molds as quickly as possible.
The weight of a specified volume of material (foam).
In some countries this is expressed as pounds per cubic
; in others it is expressed as grams per cubic
or kilograms per cubic
The graph plotted from variations in density
occurring in foam
samples due to physical
problems of heat loss, surface wetting, and shearing of foam
during movement. Because of these factors, most foamed articles exhibit a variation
from the outer skin
into the geometrical center. When this variation is plotted on a graph, the
result is a density profile shaped like the letter 'U'.
The process whereby shaped foam
articles are stamped out of a sheet of foam
by the impact of a die against the sheet of foam. This can be done by an impact
device hitting a steel-rule type die on an individual basis, or by a special
roller die compressing the foam
a cutting bar or roller on a continuous basis. This is a low cost method of
providing very unusual shapes. Another name for this process is 'clicking
The lowest cost dies for this type work are called 'steel
' and consist of specially shaped, sharp edged steel straps imbedded
in a wooden backing. See also clicking
and clickable foam
Is an examination technique whereby the foam
may be heated to destruction while a temperature profile recording is being
taken. This test assists the developmental chemists and engineers to better
understand the behavior of foams during exposure to high temperature and flames.
Is one of the major chemicals used in the manufacture
Tolylene diisocyanate (TDI
which is currently the most popular one, is an Aromatic chemical having a benzene
ring type structure and two isocyanate
(NCO) groups attached to two of the six possible positions. The most commonly
used type of TDI is a mixture with approximately 80% of the molecules having
one of the NCO
the ortho position and one in the para position with the other 20% of the molecules
having both NCO
the ortho position. One of the reasons for the warning against allowing this
type material to freeze is that these two isomers
will selectively separate during freezing, changing final foam
properties if reacted partly frozen.
Is a term sometimes applied to a liquid that resists
being moved but is quite fluid at rest. Some of the polyols
used in the manufacture of urethane
are not Newtonian (water- like) fluids
and can be described by this term. They are characterized as being very difficult
to handle, particularly at higher flow
rates. The phrase 'high elastic
component of viscosity
' is also used.
A material used to extend or bulk up another material
without changing the reactivity of the original material other than by the dilution
occurring. The term is usually applied to fluids; whereas the words bulking
, extender and filler
used with solids. This type material is also called 'liquid
Ability of a plastic
part to retain the precise shape in which it was molded, fabricated, or cast.
A substance (comprising molecules) formed from two molecules
of a monomer.
The port or opening through which the chemicals are discharged.
This term is usually restricted to the final discharge of the mixed materials
rather than to intermediate points opening into the mixing
, which are normally called metering
or metering tubes
The gradual yellowing of urethane
due to a photochemical reaction occurring
from the effect of certain wave lengths of light. It is faster in sunlight than
in artificial light, although it occurs in both. At the moment there is no inexpensive
method of prevention, although several methods are in use to retard the reaction
and to lessen the final extreme of discoloration. It is possible to mask the
reaction through the use of colorants
Occasionally fresh foam
will discolor in
the center of the Block
for several reasons,
one of which may be an excessively high internal temperature.
A term which on urethane
equipment refers to a manifold arrangement
used on continuous or non-recirculating systems for collecting the various component
together to enter the mixing
. There is no valving in this type Block
although there may be valves in the feed lines.
A slang term used by some as a synonym for buckshotting.
Long lines of undesirable large bubbles rather close
together and usually just under the top skin
. They generally result from a combination of excessive channeling
and too much air entrapped in the liquid deposited on the moving conveyor
. The channeling
line up the bubbles and carry them under the foam
front resulting in dribble marks. These unsightly chains of bubbles create a
low tensile line at which tears or rips can easily initiate.
Dry Heat Aging
An accelerated aging test that helps to screen out formulations
that may have a tendency to deteriorate too rapidly under certain climatic conditions.
samples are exposed to dry heat
for varying periods of time as specified in ASTM
Test Method D 1564-63T.
A term sometimes used to describe the stability achieved
after all operating variables are in balance on a continuous
production line, and the
remain at an exact point indefinitely.
A mixing head capable of being used for conventional
or froth pours with no modifications other than the substitution of metering
or 'mixer housings'.
Component of Viscosity
A term used to describe the resistance of some fluids
to flowing under certain conditions of shear and applied force. Under these
conditions the liquid may behave more like a rubber than a water-like fluid,
The point of deformation beyond which a material will
permanently deform rather than elastically recover. See yield
. The Method of Test for this is described in ASTM
A ratio between the force applied to cause the deformation
and the resistance to that force by the material being deformed. It can be determined
for samples in tension as well as compression. Where a straight line graph is
not produced, a tangent line to the largest part of the curve is used to express
the ratio. The modulus must be determined below the point at which the elastic
A rubber-like material not necessarily made from what
we conventionally think of as rubber. In the urethane
industry, elastomers are ordinarily thought of as the solid or non-foamed materials,
but there are exceptions known as "blown elastomers" which have been foamed
by methods conventionally used for expanding rubber rather than the methods
used to make urethane
The percent of its original length to which a specially
shaped sample will stretch before breaking. The Test Method is described in
to a formulation
that aid in stabilizing
a mixture, between the time it is mixed and poured and the time it starts to
foam, by the formation of an emulsion
This becomes important at times as not all the isocyanate
materials are readily miscible with all polyols
creating a tendency to separate
quickly after the mixing of the components
A suspension of fine droplets of one liquid in another.
Is the molecular weight of a chemical divided by the number of reactive (functional) groups.
For example, the molecular weight of pure TDI
is 174, the number of reactive groups is two (it is a diisocyanate
so the equivalent weight is 174/2 or 87. In a formulation
the number of equivalents of TDI must be balanced against the number of equivalents
of water and polyol
in order to achieve
. The equivalent
weight of isocyanate
often determined by the Amine
test method and consequently the equivalent weight of the material may be called
The heat liberated by some of the chemical reactions
occurring in the foaming mass. Urethane foam
reactions fall in the general class of exothermic reactions, which have heat
as a by-product. Under some conditions this heat becomes excessive and can damage
the foam. Large pours or high density
are particularly critical
in this respect because of the excellent insulating ability of the foam.
The final mixing of the liquid ingredients outside the
final discharge nozzle
on the way to
the target surface. This is normally accomplished by turbulence created by air
jets, and thus the mechanism or device is usually classed as a spray gun. An
advantage of this type mixer is that a solvent
is theoretically not required.
A slang expression meaning to adjust as closely as possible
to the desired instrument setting by visual means or by sense of touch or feel
without making mechanical cross-checks.
An apparatus for determining the resistance of resins
and other materials to fading. This apparatus accelerates the fading by subjecting
the article to high intensity ultraviolet rays of approximately the same wave
length as those found in sunlight.
A term which refers to the practice of increasing the
of a foam sample
which give only a temporary boost in firmness that is soon lost in normal use
(flexing) of the foam
See flex fatigue
Intense heat supplied to a mold in order to raise the
temperature of the mold-foam interface to 250° F. or higher within 1 or 2 minutes
after the pour. This has been found to shorten the handling
, and to improve the quality of the skin
and ha1 physical properties of the molded article. This is used in 'one shot
flexible foam molding
Fast Heat Oven
An oven capable of supplying the intense heat required
for the fast heat
process. The most
common type are those using either gas or electric radiant heat.
An inert material added to the foam
to change the final
physical properties. Normally fillers are used to increase the density
of the product without significantly adding to the cost, or they are used to
assist in a cost reduction. The solid
often result in higher load bearing properties but lower tensile
and tear strengths.
A device to remove unwanted particles of material from
the liquid streams
of chemicals. For
trouble free operation all lines should be properly filtered.
A term which is used to describe foam
with a cell
count of 80 or more per lineal
inch, See cell size
term used to describe the reaction of foam
to a point indentation such as would occur when pressing a fingernail firmly
into the foam
article. 'Good Fingernail'
means rapid recovery with no permanent marking. 'Poor Fingernail' means slow
recovery or failure to recover leaving a line or point impression in the foam.
With experience this can be a useful screening test for relative comparisons
The practice of metering
the various fluid streams
during a fixed
time interval such as 6 seconds or 1 minute in order to calibrate and set the
liquid streams to a desired total flow rate per minute as well as to a desired
ratio with each other.
Fixed Throughput (Fixed
A term used to describe a machine with one or more pumps
directly connected to the drive motors so that no variation in flow rate is
An ambiguous term used at times to describe the more
permanently installed portions of the mechanical handling devices needed in
order to load and unload molds and to carry them through the curing area. The
term jigs is sometimes used to describe that portion of the total that aids
in fastening the molds to the fixtures.
A slang term used to describe many small splits scattered
widely throughout and on the top surface of a foam
slab or Block
. This is usually seen in
flexible slab production when the gelation or polymerization
has been excessively retarded in relation to the blowing' reaction.
The practice of sticking together or gluing flexible
and fabric by melting one surface
of the foam
with radiant heat and quickly
pressing it to the fabric before the melted material resolidifies. For best
results a slightly thermoplastic formulation
(normally classed as a thermoset)
is needed. See definition of thermoset
Has several meanings according to the Test Method used.
In general, it can be said that a flame retardent material imparts a certain
degree of flame retardancy to a foam, i. e. the foam
will burn less rapidly or lose less weight on burning.
Describes the relative burnability of the material in
a specified situation. Meanings vary according to the test method used.
The external symptom of large internal blows
or voids. These generally develop just past the peak
and are usually semi-circular tears in the top skin
that connect with the internal voids. Under extreme conditions they may occur
prior to the peak rise point
Flashing or Sparkling
A condition in continuous
foaming, during which there is a continual release of tiny bubbles
of gas from the surface of the mixed material just after it has been poured
on the conveyor. It may continue until the foam
has partially expanded. Under certain conditions of light reflection, the foam
appears to sparkle. It resembles boiling
to some extent, but the bubbles are so tiny that no collapse
occurs and foaming proceeds normally as soon as the material viscosity
has increased to the point in which all gas is trapped.
Flat Blade Impeller
A mixing blade that is characterized by a generally single
plane shape or flat appearance. It may be solid, perforated with various patterns,
or may be irregular in contour.
The loss of physical properties of a foam
sample undergoing continuous flexing of a specified magnitude, duration and
rate. The Test Method is described in ASTM
The rubber like material used for molding
very intricate shapes and contours into rigid foam. These materials can be any
but are more usually urethane
or silicone based. The usual compounds are liquids which are poured over the
'master', allowed to gel, then removed and oven cured to maximum tensile strength
A special metal spindle that attaches to a motor shaft
at one end and permits coupling of the flexible shaft to the other. These Adapters
are different for each motor shaft size and for each flexible shaft size.
Shaft Mixer Drive
A long flexible coupling between the mixer drive motor
and the mixing head. This type drive shaft is often used when the mixing head
must be moved during operation. The drive motor is remotely located in order
to cut down on the weight and inertia of the mixing head assembly. Durability
of the shaft is good if properly installed and used according to the manufacturer’s
specifications. This arrangement is also called 'remote
The strength of a material in bending, expressed as the
tensile stress of the outermost fibers of a bent test sample at the instant
of failure. With plastics
, this value
is usually higher than the straight tensile strength.
A term used to describe a special lid used on some flexible
cushion molds. The lid, which has
a specified weight per square inch, is suspended above the foam at a position
near the desired maximum rise and is free to float on the surface of the rising
against the gradually increasing compression
of springs. The use of this type lid appears to minimize the appearance of loose
and hard spots
in the cushions.
Rate of all chemicals.
device usually consisting of a glass tube containing a float which rises or
falls in response to variations in flow
of a fluid through the tube. These are usually not accurate enough to serve
as anything other than 'guides' to metering
A term which refers to the quantity of chemicals delivered
to the discharge nozzle
or metering port
in a specified time interval, usually expressed in pounds per minute per component,
in the USA. 'Total flow rate' would be the quantity of mixed liquid discharged
from the mixing chamber
in the required time interval (the total of all individual component
A term which refers to the general family of fluorinated hydrocarbons to which
belong some of the most popular low temperature boiling
chemicals used as blowing
In the sense the term is used in the urethane
industry, a product, either flexible
or rigid, that has been produced by the internal generation or liberation of
a gas in a fluid medium that is simultaneously polymerizing while expanding
in volume, The bubbles that make up the final product may be completely interconnected
(open celled) or walled off from each other (closed cell).
The loss of physical properties of a foam
article in use. Some loss is to be expected. The most noticed problem is the
softening of cushions. Better quality foams would ordinarily be expected to
fatigue less than poor quality foams.
Refers to the deposition of foams and requires that the
foaming machine be brought to the work which is 'in place' as opposed to bringing
the work to the foaming machine.
The list of ingredients and their proportions to each
other which must be used to make a particular foam
A term used either as a synonym for formula
(the list) or used to refer to the chemicals that would be used in the preparation
of a foam
from a formula
Free Rise (Unrestrained)
The unhampered expansion of a foam
sample or product in a container with no top and a height of side wall not greater
than twice the diameter. This is normally used in most laboratory sample screening
work and is the normal condition in the slab process. The lowest possible density
with a particular formula
under free rise conditions.
A term used to describe rigid foam
with such a low tensile strength that any wiping of the surface or jarring of
the sample produces a fine powdery dust. Some formulations
go through a friable stage of cure, others remain friable permanently. This
is generally regarded as a highly undesirable property.
Froth (Frothing, Froth Process)
A term which refers to the practice of incorporating
an unusually low boiling
the final foam
mixture (in a pressurized
). When this liquid
is discharged from the pressurized chamber, it expands instantly into a semi-liquid
(froth). In normal practice enough
of the special frothing gas is added to the mix so that this initial or pre-expansion
produces approximately one third of the total expansion of foam
required. The remainder of the expansion is by the normal procedure. Fluorocarbon
12 is the most common low boiling
used for frothing.
Froth Mixing Head
The practice of atomizing a frothed discharge from a
mixer and spraying the particles of semi-expanded material onto a vertical or
overhead surface. This has the advantage of practically no slump on a surface,
over widely varying temperatures, and results in minimum final foam
due to self insulation
from the surface on which the froth spray is applied. The final product has
the disadvantage at present of a rather irregular surface.
A term applied to a urethane
machine designed to permit all fluid
to be circulated between
the tank and the mixing head during the 'idle' or non-production time. For 'full
recirculation' the valve that diverts the flow
to the mixing chamber
immediately adjacent to the chamber so that stagnant areas are eliminated. See
short recycle valving.
Automatic Solvent Flush
The number of reactive groups attached to a single molecule.
with a functionality of 2 would
be a diol
The net weight loss of chemicals during foam
production, determined by subtracting the total weight of foam
produced from the total weight of chemicals used. In most cases this refers
only to the carbon dioxide generated in a water blown formula
. In some cases it is used to refer to evaporation and eventual loss of the
fluorocarbon. To avoid confusion the type of gas loss should be specified.
A thin coating of a high quality polyester
applied to the surface of a
mold prior to filling the mold with foam. The foam
adheres to the gel coat so that the part, when removed from the mold is finished.
An expression of the stability of the foaming mass. This
is at least partly dependent on the increasing viscosity
of the liquid. A foam
with high gel strength
would be very stable and could withstand more shearing stresses in molding
than could a formulation
The speed with which the chain
and cross linking
reactions are occurring in the foaming mass. This rate of reaction must be balanced
with the rate of gas generation so that gelation occurs just after peak foam
rise in order to achieve the best quality product. See reaction
Foams or formulations
that are capable of being used in a wide variety of Applications
without modification while still attaining a reasonably high level of physical
A term used to refer to a machine used to produce small
particles from foam
trim. These devices are also called shredders
cutters and hammer mills
. See crumb
An extra thermostat in the electrical circuit of a heating
system, used as a safety control over the maximum temperature of the heating
The chemical symbol used to represent water.
H2O Blown Foam
The practice of weighing all the ingredients of a foam
separately into a mixing container
and stirring the mixture with a spatula or paddle for the appropriate mixing
period, then pouring this mixture into a mold. Although usually practiced only
in laboratories, there are some commercial operations based on this method.
The time, in a molding
process, between either the start or the completion of the pour and removal
of the product from the mold without damage. In the continuous
process it is often referred to as the time between deposition of the
liquid mixture on the conveyor and the time the foamed Block
containing the specified portion of chemicals can be lifted from the conveyor
and handled without damage. In Batch
it can also be 'the time between completion of mixing and pouring
into the mold.' See cream time
A term which refers to the firm high density
areas formed in a molded object when packing
is excessive or poor distribution occurs. This firm area or hard spot is normally
caused by a localized collapse
in again by excess foam
from the surrounding
The smoke or fumes released from the foaming mass under
normal conditions of continuous slab
processing, particularly at peak rise or just after. Under exceptional atmospheric
conditions, the smoke or haze may obscure the surface of a large area of the
A shortened form of the word mixing head, used to describe
devices ranging in complexity from simple manifolds to complex diverting valves
having attached mixing chambers
, drive motors, etc.
Head Mounted Drive
Little bubbles popping up through the top skin
of a continuous flexible slab or free rise
pour just past peak rise.
From the very first days of the industry this was recognized as a sign that
the resultant foam
would be open celled
and generally of good quality. The word is a direct translation from the German
phrase brought to the USA with early technology. The bubbles do not have to
be present to make good foam
presence does no harm and is psychologically reassuring,
The temperature at which a sample of foam
will begin to change dimensions under specified conditions of loading and environment.
The Test Method is described in ASTM
794-49, but the temperatures and times used are varied to suit the end use.
Exchanger, Multiple Pass
A heat exchanger for either heating or cooling one of
the chemical components
that does not have sufficient capacity to bring that component
to the desired temperature in a single journey or pass through, but rather requires
multiple recirculations of the component
to condition the material properly.
A heat exchanger combined into a single unit with its
source of heating or cooling. An example would be a scraped surface heat exchanger
with an attached refrigeration compressor that can be reverse cycled to provide
both heating and cooling. heat exchanger, scraped surface-a heat exchanger so
constructed that the heat conductive surface is continually scraped to remove
the temperature conditioned material. This type is normally used for cooling
those materials that tend to increase in viscosity
enough to stick to chilled surfaces, interfering with the efficiency of the
A heat exchanger for either heating or cooling one of
the chemical components
that has sufficient
capacity and control instrumentation to bring that component
to the desired temperature in one journey or passage through.
Exchanger, Tube and Shell (T & S)
A heat exchanger constructed of a bundle of tubes inside
an outer casing or shell. This type is used for either heating or cooling of
having low enough
not to interfere seriously
with the efficiency of the heat exchange surface. The chemicals to be conditioned
may be circulated either through the tube or through the shell portion.
Heat Of Reaction
The liquids or gases used to convey heat to or from a
heat exchange surface. See cooling
A method of joining plastic
films by simultaneous Application
of heat and pressure to areas in contact. Heat may be supplied conductively
Is the condition in free
or molded articles of having a very thick, high density
. This is generally undesirable
economically in flexible slab foam
and can be caused by a defect in the formulation
or in the environment. It is highly desirable in some molded articles, both
flexible and rigid. Self skinning or integral
More properly termed 'stator helix mixing', a term used
to describe the practice of mixing the chemicals by means of turbulent flow
conditions created by injecting a high velocity gas stream
into a helically spiraled pathway simultaneously with the individual chemicals.
The developmental work on this type mixing was performed by the duPont Company
in an effort to create a light weight low cost froth dispenser. The stator helix
can be used for frothing
when a gas such
as fluorocarbon 12 is used as the high velocity gas stream or it can be used
for conventional foaming if compressed air or nitrogen is used as the mixing
gas. This is a useful system where quality requirements are average and the
product is confined in a metal or plastic
A term describing the mixer used with the helical
technique. The phrase is somewhat ambiguous since many of
the rotating impellers
into a helical spiral shape. In order to avoid confusion it should be specified
as a stator or non-rotating helix.
High Rise Application
High Shear Mixer
A mixer blade or impeller
of the general type that mixes primarily by smearing multiple thin films of
chemicals together in a high-speed close tolerance
device. Generally associated with this type is a high mixer drive motor power
loss and the transfer of a large amount of mechanical energy to the chemicals
in the form of heat.
A term sometimes used to describe storage tank(s) in
which stable premixes
are made and then
held until the material is required to be transferred to the "run" tanks on
Hold-Up (In The Mixing Head)
The actual volume of chemicals in passage or in transit
through the mixing chamber
mixing operations. This is usually not the total volume of open space in the
, since centrifugal
force generally keeps the center area open. Any built-in pumping features of
will slow or speed the
passage of the material through. Hold-up can only be increased if the mixing
is partially empty to begin with. With pumping type impellors, hold-up
is rarely increased significantly by reducing the diameter of the discharge
The practice of cutting foam
when the cutting portion of the blade of the saw is in a plane parallel to the
horizon. Special rotary bandsaw mechanisms are most commonly used for this purpose,
although hot wire cutting
are also used.
The practice of pouring large panels of urethane
(particularly rigid foam) when the
mold or void to be filled has its two largest dimensions form a horizontal plane.
This has the advantage, when anisotropy is present, of having the greatest compressive
of the material in a direction that supports the external skins
Hot Wire Cutting
The practice of cutting foam
by means of an electrically heated wire held taut between two posts with the
help of a spring tensioning device. This has the advantage of eliminating dust
and can be installed in multiple levels so that an entire Block
can be cut in one passage. Disadvantages are the tendency towards rather slow
production rates, the variability of response of different types of foam
requiring critical adjustments, the possibility of unpleasant odors, and the
ever-present possibility of fire. (The wire is maintained at 1200° F.)
An accelerated aging test under conditions of high humidity
and temperature. The Test Method is described in ASTM
D 1564-63T under steam autoclave test.
A system in which energy is transferred from one place
to another by means of compression and flow
of fluid (e.g.. water, oil).
drive motor for the mixing head in which the motor segment is head mounted and
the power unit is remotely located in order to decrease the total weight of
the mixing head installation. This also provides variable speed adjustment.
A spreading device of the type that can be used on continuous
production lines, utilizing a hydraulic
A mixing device in which the primary cause of mixing
is the turbulence created by the interference of the streams
of liquid components
with each other
as they are introduced into the mixing area. This is also called a fluid jet
A term which refers to the ability of the foam
product to withstand hydrolysis or dissociation by water under conditions of
constant exposure. The humid aging
Test Method was developed in an attempt to measure this.
An affinity for water. Hydrophilic foams are more absorptive
and generally make better sponges
Hydroxyl (OH) Group
The combined oxygen and hydrogen radical that forms the
reactive group on polyols
in the sense used in the foam
industry, a term which refers to the decay in strength properties under continuously
applied load. A typical example of this would be in the determination of RMA
values where the test specifies that the reading must be taken at an exact time
interval after the application
of the load in order to assist in obtaining a reproducible value, since the
values drop continuously.
A shortened form of Indentation
value, formerly known as RMA
value. A series of readings would be used to make an IFD curve, a single specified
reading such as the 25% IFD value would be used for direct comparisons. The
Test Method is described in ASTM
IFD (65/25) Index
A ratio of the 65% compression value divided by the 25%
value. This ratio or index
to some extent, a more or less linear relationship between readings taken to
form a resilience (IFD) curve. Index readings above 2.00 are usually considered
good for urethane
foam; while index
readings below 1.75 are considered poor, and the foam
can be described as 'boardy
A term used to describe the power driven mixing blade
that is used to mix urethane
in a mixing head.
The shell surrounding the impeller
and forming the outer limits of what is commonly called the mixing
. This is often readily removable for cleaning purposes. It may be
smooth, grooved, or baffled.
A measure of the stoichiometric balance or the relationship
between the equivalent weights of the combining substances. In the case of urethane
foam, this is the relationship between the equivalent weights of the isocyanate
materials on the one side and the water and polyol
equivalent weights on the other side. An Index of 100 indicates that both equivalents
are equal or ‘balanced'. An Index of 95 indicates that there is a 5%shortage
while an Index of 105
indicates a 5% surplus of isocyanate
A slight theoretical excess of isocyanate
usually 3-5%, is common practice, particularly with flexible foams. Other levels
may be specified with special formulations
The ability to control the rate of flow
of one or more of the components
any amount desired. This is very ambiguous, since maximum and minimum limits
must usually be specified to obtain the desired tolerances
. Some degree of infinite
control can be achieved with pressure pot metering
drive motors, variable pitch sheaves, variable contact cones, etc. With some
of these a wider range of control is achieved by the sacrifice of stability
at a specified setting.
A substance that slows down chemical reaction. Inhibitors
are sometimes used in certain types of monomers and resins
to prolong storage life.
A spot of off-quality foam
located at the point where the first amount of liquid mixture was deposited.
This can be due to improper pressure
, unbalanced discharge velocities, extreme differences in viscosity
oversized mixing chamber
A synonym for cream
. In frothing
it usually refers
to the delay time between the initial expansion and the beginning of the secondary
or final expansion.
whereby a heat-softened plastic
is forced from a cylinder into a relatively cool cavity which gives the article
the desired shape.
Cutting machines that have been installed directly in
a continuous slab foam
production line so that handling of the foam
is minimized. Some manufacturers trim
the top, bottom, and side skins
point; others go all the way and make all the cuts in-line.
Heat exchangers that have been installed in the flow
circuit so that the pump must be operating for the exchanger to be effective.
This serves to differentiate between this type and the blanket type units that
are wrapped around machine tanks
A special mixer that has been added to one of the flow
circuits in order to premix
one or more
of the minor ingredients into one of the major component
. A common use is to premix the
silicone and air into the polyol
at a point just prior to the final mixing zone.
A word used to describe the entire foam
producing mechanism after it has been placed into its operating environment
and provided with all the services required.
An instrument utilized to determine the tensile, compressive
properties and other mechanical properties of foams.
Integral Skin Foam
A molded urethane
product having a dense, tough outer
and a relatively lower density
The product is achieved in a single pour through a combination of chemical and
The practice of using a single power source to drive
two or more fluid metering system
Each fluid metering systems
be independently variable in output to provide for setting an exact ratio between
, but changing the speed
of the master drive motor would change the total flow rate without disturbing
the ratio. This is also called a 'master-slave' system.
The practice of mixing the various components
inside a mixing chamber
or housing and then discharging the mixture through one or more discharge ports.
This is usually a more efficient mixing device than an external mixer but generally
requires some solvent
cleaning at intervals, dependent on the formulation
relative on time, duration of off times, etc. See external
A technique of pouring individual Blocks
of slab foam
in boxes of a definite length
in order to make a wider and higher Block
than would ordinarily be possible with the maximum flow rate of the machine
available. This is possible because the box ends Block
movement, forcing the foam
upward. On continuous slab
upstream side is always open, resulting in a required increase in conveyor speed
to prevent the foam
from falling over.
The foaming and swelling of a plastic
when exposed to high surface temperatures or flames. It has particular reference
to ablative urethanes
used on rocket
nose cones, and to intumescent
. It is extremely useful for fire resistance.
Coatings which when exposed to flame or intense heat
decompose and bubble into a foam
protects the substrate and prevents the flame from spreading. Such coatings
are used, for example, on reinforced plastic
A term used to describe foam
that has a mixture of widely varying cell
sizes and presents a very irregular appearance. This effect is sometimes caused
by excessive air introduced to the mixing head and sometimes by certain chemicals
added to the formulation
The family name for those chemical compounds having one
or more reactive NCO
radicals or groups
attached to the main molecule. Tolyene diisocyanate is the most commonly used
member of this group.
Any one of two or more chemical compounds having the
same number of the same kind of atoms in their structure, but arranged in a
different way. This change in structure sometimes affects the reactivity rate
of the compound. In the case of tolylene diisocyanate
a definite mixture of isomers is provided to the customer. The most commonly
used mixture is an 80/20 blend. See isomer
Is the ratio between the 2.4 isomer
and the 2.6 isomer
commercial TDP. The 50/20 ratio of 2.4/2.6 isomer
is the most common blend although the 65/35 2.4/2.6 isomer
blend is also available.
Foam characterized by having the same strength proper-
ties in all directions. To achieve this the rigid foam, in particular, would
have to have 100% spherical shaped cell
. In actuality the foam
normally achieve a regular dodecahedron shape rather than Spherical. See Anisotropic
for additional information.
A term which refers to a tank having an additional metal
shell, coils of tubing or resistance wire surrounding the inner tank in order
to utilize the tank as a heat exchanger. The most common form of this is the
separate outer shell through which steam can be introduced for heating purposes.
Using this sort of tank for a chiller
may cause problems with condensation. Insulation is sometimes used to gain efficiency.
Jigs and Fixtures
Usually a short length of hose needed when installing
a device 'in-line' in the flow circuit of one of the components
'. The existing hose is attached to either the inlet or the outlet of the new
device as required, and the jumper hose then is installed between the other
connection and the point of original attachment of the original hose.
A measure of the insulation ability or thermal conductivity
of the foam
or material. In English measurements
it is normally expressed as BTU’s / hour / square foot of area / degree F /
inch of thickness, although some physical handbooks use a foot of thickness
as standard. Since the measurement indicates positive heat flow, the relationship
to insulating ability is inverse in that the higher the K factor, the poorer
is the insulation and vice versa. Since the approved Test Method is so time
consuming and expensive, many faster cheaper screening methods are in use.
A high density
layer of foam
indicating the joint between
two adjacent pours of foam that did not flow
together until after skins
Under ideal conditions the various parts of a pour should flow
together while still liquid, thus avoiding the formation of knit lines. This
is a common occurrence with rigid foam.
A term which refers to the technical background information
required in order to properly operate a specific process.
A process similar to helix mixing, except the mixing
is irregularly baffled instead of spiraled.
A term which refers to the delay or reduction in flow
that occurs when a restriction in the flow
circuit causes a build-up in pressure. This delay is particularly severe in
systems that may have trapped air
or gas in some portion of the circuit or in those systems that use accumulators
or flexible hoses. When using 'on-off'
the pressure must be balanced between recirculation and mix
or a surge
or lag may occur.
The process of adhering 2 or more thin sheets of the
same or different materials together to form a thicker product with possibly
different properties. In the flexible foam
industry in particular, it refers to the process of adhering thin sheets of
and fabric together. Two
processes are in common use, flame
and Adhesive Lamination
A paper or foil covered rigid foam
board may be made by self-lamination of the chemical to the skins
Laminates are also made of rigid foams
, metals, wood, and other
A term used to describe the problem of non-uniform or
off ratio flows at the instant of starting or stopping the mix cycle in 'on-off'
. When complete control over flow
conditions is not obtained, one material may 'lead or lag
the other material (s). The most common cause of trouble is a lack of proper
in the flow
circuit between the mix cycle and the recirculate part of the cycle. Uneven
velocities of discharge from the orifices may also cause trouble, as will one
of the liquid streams
away from the impeller
the other is directed towards the shaft.
A term occasionally used on flexible slab production
lines to describe the distance between the mixer and the cream
. See cream line
The device, used in frothing
that provides the transition zone between the higher pressure in the mixing
and atmospheric pressure. It can vary in design from the readily
adjustable (by pneumatic pressure) rubber sleeve type valve to a short length
of hose that is squeezed by a C clamp. The object is to keep the mixture as
a liquid as far down the nozzle
as possible so that shearing of the bubbles is minimized. The discharge tip
of the nozzle
designed to minimize air turbulence so that a smooth 'rope
of froth is produced.
That portion of a let-down
that can be classified as a controllable valve. A let-down valve
is usually employed in the production of froth foam
The ability of a plastics
material to resist fading after exposure to sunlight or ultraviolet light. Nearly
tend to darken under these
A long chain molecule as contrasted to one having many
side chains or branches.
The technique of introducing the least reactive material,
usually the polyol
, into the mixing
at a point just below the mechanical seal, so as to lubricate the
mechanical seal and act as a buffer to prevent direct contact of the seal with
. This is most useful
with continuous mixers
it being difficult to maintain the liquid seal and ratio balance during rapid
A term used to describe a long narrow Block
that is to be 'peeled'. See peeler
A phenomenon in molding
in which the skin
of the molded article
is a loose intact film. This is normally caused by excessive movement or flow
of the foam
after gelation is too far advanced.
In general, laminates molded and cured in the range of
pressures from 400 psi down to and including pressures obtained by the contact
of the plies.
Low Shear Mixing
A mixing technique whereby the liquid components are
mixed primarily by rolling and stirring the chemicals in a mixing
of relatively large volume. Power loss and mechanical energy transfer
in the form of heat are generally quite low. The pin type mixer is generally
described as a low shear mixer. See high shear mixing.
Temperature Boiling Solvent
A device installed in an air line feeding a pneumatic
device (air motor or piston), requiring small amounts of lubricant for best
performance and service. The device meters the required amount of lubricant
into the air as it passes through on the way to the air motor or piston.
Mn (Number-Average Molecular Weight)
The total weight of all molecules divided by the total
number of molecules.
Mw (Weight-Average Molecular Weight)
The sum of the total weights and molecules of each size
multiplied by their respective weights divided by the total weight of all molecules.
A service provided by some machine manufacturers to start
new machines in operation. The manufacturer provides an experienced technician
who trains the customer’s personnel in the proper operation and maintenance
procedures (usually on site). Since these machines are often rather complex,
the service is quite valuable. A rule of thumb often quoted is that 'proper
operation is 50% of the profits'. Sometimes the service is included in the cost
of the machine; at other times it is extra.
Those tanks that form a part of the operating system
of a foam
machine, usually mounted on the
machine frame with the metering
either inside or directly beneath.
A switch, included on the control panel by some machine
manufacturers, that permits the operator to choose between automatic dispensing
controlled by the timer or manual control timed by the operator.
Solvent Flush-Squeeze Bottle Type
Solvent Flush, Valve Type
A term which refers to a permanently connected solvent
system that requires manual opening and closing of a valve. The solvent
may be supplied by a pump or pressure pot. A manually operated air flush may
also be included.
A term which refers to the influence that the total amount
of chemicals poured has on the density
, etc. A small pour generally
requires a higher catalyst
a much more careful control of the environment than does a larger pour in order
to achieve the same properties. The 'surface
to volume ratio
' of the mold and the mass of the mold also has an influence
A term sometimes used to describe the mixture resulting
from premixing as many minor ingredients as possible in with the polyol
in order to reduce the final number of components
’ to the lowest possible level or to have time to blend efficiently a chemical
that is not very miscible with the polyol
A term used to describe the basic chemical supplier,
sometimes called 'raw material supplier'.
An ambiguous term sometimes used to refer to the machine
tanks built into or onto the metering
and sometimes used to refer to the material storage tanks in which
bulk chemicals are stored until needed.
That material within which something originates or takes
form. In the case of urethane foam
bubbles originate within a liquid matrix.
A term used in the USA to describe the cushioning material
applied to a bed in order to make it more comfortable. A single bed mattress,
in the USA, generally measures approximately 39 inches wide by 72 inches long
by 4 inches or more thick, although there are many variations of this. A double
bed mattress, in the USA, generally measures 54 inches wide by 72 inches long
by 4 or more inches thick, again with many variations. Other countries have
different names and different dimensions for this article.
A drive system for mixed liquid spreaders
or traversers that takes all reversal thrust directly on gear teeth, screw threads
or some other non-shock absorbent device. This type of drive system generally
has a greater maintenance problem than the pneumatic or hydraulic
A mixing device in which the primary cause of mixing
is a power driven rotor
which, by its speed of rotation and configuration, imparts turbulence to the
fluids as they enter the mixing zone
The repeating structural unit of any high polymer
Metal Belt Conveyor
A particular type of metal surfaced conveyor in which
each slat interlocks with its neighbor in such a manner that a chain link is
formed across the entire width of the conveyor. This type is often used for
continuous slab foam
Metal Slat Conveyor
A type of metal surfaced conveyor used in the foam
industry in which the metal slats are supported at each side of the conveyor
by a chain and are not themselves interconnected as in the metal Belt
. The term is also used to describe the practice of collecting the
simultaneous flows of the various components
in individual cups for definite time periods in order to check the calibration
of the machine.
through which the final components
are introduced into the mixing chamber
These may or may not be replaceable to assist in balancing pressures. Pressure
balancing is very important to good molding
and readily replaceable tubes are very important not only for start-up but also
for maintenance cleaning. See metering
The pumping system used to accurately control the flow
of the liquid plus all the hoses, valves, gauges, and piping needed to make
a complete flow
A chlorinated hydrocarbon that is most commonly used
as the cleaning solvent
in the urethane
industry. It is the most effective
of the cheaper, non-flammable solvents. Many other solvents are more or less
effective and can also be used. Flammable solvents should not be used.
A term which, in the rubber industry, refers to a roller
type mixing device that is effective with mixing very high viscosity
materials such as gum rubbers and elastomers
In the paint industry as 'Ball Mill', it refers to a rolling type mechanism
that revolves a drum in which pigments and powders are dispersed into a resinous
medium by means of heavy pellets also contained in the drum. A 'hammer mill'
is used to produce finely divided pieces of flexible foam
from flexible foam trims
. See crumb
A mechanical device capable of mixing two or more materials
Helix or Helical Spiral
Mixing, High Shear
Mixing, Low Shear
The section of a mixing head in which the final. combination
of the ingredients occurs. It is usually that section contained within the impeller
Mixing Chamber Port
A mechanical device capable of mixing two or more materials
together homogeneously in one passage through the mixing
, It may include valves, bearings, motor, etc. See mixer
and Batch Mixer
Mixing Head Hold-Up
The portion of a mixing
in which mixing is actually accomplished. Normally the mixing zone
is around the outer perimeter of the impeller
Modulus of Elasticity
The ratio of stress to strain in a material that is elastically
deformed. moisture vapor transmission-the rate at which water vapor permeates
through a plastic
film or wall at a
specified temperature and relative humidity.
Thin shaped films of plastic
or treated paper that fit smoothly into the mold cavity and are used in place
of mold release. The liners may or may not form the finished surface of the
molded article. Vacuum formed vinyl and ABS skins
are often used.
A term which refers to the slight excess of the actual
quantity poured into the mold over
that actually required to fill the mold under ideal conditions, particularly
for rigid foams
. The excess usually
is set at some point between 5% and 15% over the exact amount required. This
extra material serves as a buffer to absorb slight changes in material temperatures,
mold temperatures, distribution of materials, etc., and also seem to aid in
reducing rejects caused by skin
It is also said to aid in improving load bearing properties of the foam. Flexible
techniques do not generally
in excess of 5% due to
the formation of hard spots
excessive internal pressure conditions.
Mold Release Agent
One of many chemical compounds which, when applied to
the mold surface, serve to prevent the cured foam
from sticking to the mold. Because of the many variations in the formulations
used in urethane
foam, no one class
of releases seems to have a clear advantage over others. Classes of releases
that have proven useful include telomers, silicones
waxes (both synthetic and natural), and soaps of various sorts. One of the more
useful. concepts used for flexible foam
release involves the use of a microcrystalline wax which is a solid at the temperature
of the mold during pouring, but melts during curing so that the final release
coating is a liquid film.
The practice of pouring the mixed liquid foam
ingredients into a shaped cavity, closing the cavity, allowing the foam
to expand and cure
to the handling point,
and then removing the foam
the cavity. Good molding practice usually dictates control over the temperature
and quantity of the foam
the temperature of the mold surface, the distribution of the liquid in the mold,
temperature, the cure
and the venting of the displaced gas from the mold.
A term used by some continuous
process companies to describe the individual(s) that supervise the
production of the foam
by direct observation
of the foaming process, the instruments, the final foam, etc.
A term suggested by some to be used in the foam
equipment field to describe those machines that are portable
only with the use of many men or heavy lifting equipment.
A term used to describe a formula
or machine that requires handling two or more liquid ingredients at the point
of final mixing.
A technique used to overcome deficiencies of formulation
or equipment in the filling of molds, particularly thin, high rise cavities.
If a single pour in the mold cavity would deform the walls or would result in
an uneconomically high density
wall would preferentially be poured in layers. The foam
rise in each layer is restricted to that amount associated with the best properties
in the foam. Usually each layer is permitted to harden before adding the next,
If the equipment does not have sufficient capacity of flow rate to fill the
cavity in one pour without seriously damaging the rising foam, then the cavity
must also be poured in layers. The height of each layer would then be determined
by the flow
rate of the machine.
The chemical symbol for nitrogen. Nitrogen is often used
as an inert, dry gas blanket over the chemicals in the otherwise sealed chemical
tanks in order to avoid problems with moisture contained in atmospheric air.
The chemical symbol for the isocyanate
reactive radical or group.
Nitrogen (Gas) Blanket
A term used by foam
machine manufacturers to indicate a throughput
rate capacity that a particular
machine was designed to handle with 'normal' formulations
Because of the extreme variability in the type of chemicals that can be used
to make urethane
foam, not all formulations
process the same way on the same machines so that a machine capable of metering
and mixing 30 pounds per minute of a 1000 cp viscosity
material might only be capable of metering
and mixing 10 pounds a minute of a 20,000 cp viscosity material.
A rather ambiguous term permitted to be applied to certain
fulfilling certain conditions of test outlined in Test Method ASTM
D 1692. In actual use particularly in confined areas, some, but not all, of
the foams with this label may burn quite rapidly; therefore, if a foam
is required that will not contribute fuel to a fire under any circumstances,
a different method of test must be used. Since the term is misleading, it should
not be used without precise statement as to the conditions involved.
A term generally used to describe a nozzle
that does not become plugged
in use. The term, when used by itself, should be taken to mean non-clogging
'in normal use with a normal formulation
Non-clogging under any condition of use has not been demonstrated as yet by
in which the metered chemical flow
goes directly to the mixing head and out. During off periods, the flow
of chemicals is stopped. The term is primarily used to describe those systems
in which the metering
pump itself is
stopped, although it is occasionally applied to systems in which a valve is
used to stop the flow
to the mixing head
and a pressure relief valve bypasses the flow
to another location until the valve is reopened. See recirculate system.
See helix mixing.
A term used in working with 'on-off'
to describe those components
introduced to the mixing zone
a port that is not controlled by the 'on-off' valve. For example, a 3 component
mixing head of the 'on-off'
type would normally have 3 valved ports that were simultaneously switched plus
2 additional non-valved openings that would normally be used for solvent
and air but could be used for other components
such as fluorocarbon 11and colors.
A very general term used to describe the discharge opening
or tip of the mixing head or spray gun. It is occasionally applied to the entire
mixing head, particularly if the device is hand-portable.
A term used to describe assistance applied toward the
generation of many small, uniform bubbles as opposed to the formation of a few
large bubbles in the same volume of space. As currently understood under chemically
pure conditions it requires more energy to create a new bubble than it does
to make an existing bubble larger, consequently without assistance foams would
try to form the largest possible bubbles. The assistance normally given, as
described by the term nucleation, may involve the addition of special molecules,
small rough particles, dissolving high vapor pressure gas in the liquid, forming
tiny gas bubbles mechanically throughout the liquid, or may even involve a shortening
of the time interval during which bubble formation occurs in order to minimize
migration of gas molecules toward existing bubbles.
Number of Components
Is a rather ambiguous term used to indicate the number
of separate fluid streams
the final mixing zone
. It should
normally be qualified in use to avoid confusion. For example, a 4 component
'on-off' mixing heads
normally be expected to have 4 openings into the mixing
that are controlled by the 'on-off' valving when, in actual fact,
many mixing heads have 2 additional openings that are not controlled by the
valve. Contrarily, a 4 component continuous
may have just the 4 openings with no additional ports.
A seal or gasket that has a round shape (like the letter
O) and a round cross section.
Is the number of milligrams of KOH (potassium hydroxide)
that is chemically equivalent to the activity of a specified weight (in grams)
of the polyol
. This number is used in
calculating the equivalent weight of the water and polyol
for the purpose of determining stoichiometry
of a formula
'On-Off' Mixing Head
A mixing device with a special valve section capable
of dispensing an accurate amount of well mixed foam
ingredients at periodic intervals. Start and stop should be virtually instantaneous
with no variation in foam
the first drop to the last drop. Time 'on' and 'off" can be controlled
by a wide variety of methods ranging from manual movement of a valve lever to
automatic timer control of an actuator for the valve section.
Paper Feed System
A system of paper handling for the lining of conveyors
in continuous slab foam
processing, based on a single roll of paper that is wide enough to form the
bottom plus both sides of the trough. For 84 inch wide conveyors rolls of paper
as much as 13 feet wide are required. Not all styles of paper can be purchased
in these widths, particularly release papers; and wrinkling problems may occur
if tensioning of the roll by the paper mill
has been poor or if paper alignment is bad. Because of this many manufacturers
use the more complex three
roll paper feed system
A system for the production of urethane
in which none of the isocyanate
portion has been prereacted with any portion of the polyol
prior to final mixing. A minimum of 2 components
are required, and more than 2 are often used. The ratios between the two major
are normally somewhere
between 50/50 and 70/30 for most formulations
A term applied to foam
or bubbles. Flexible
should be 100% open celled for best
quality. This characteristic is difficult to measure directly in flexible foam,
and several indirect tests are in use that measure the air flow
through a sample of a certain size and thickness.
A term which refers to the practice of pouring into a
cavity having a closed bottom and sides but an open top. The mold may be shallow
or deep. It is generally not the most economical way to mold a product but may
have an Application
internal mold pressures are required.
Are a family of urethane
that are noted for their rather specific influence on the gelation reaction.
By properly combining an organotin catalyst
with an Amine catalyst
such as triethylenediamine, a good balance between blowing and gelation reactions
can be achieved. The most commonly used catalyst
of this type is probably stannous octoate although dibutyltin
and others of the dibutyltin group are also used.
Overall Block Density
A term which refers to the practice of determining the
of the uncut foam Block
in order to provide data for process analysis. By knowing the density
at this point, an accurate gas loss
value can be computed, and trim
be more easily calculated on a weight basis instead of on a volume basis. Not
all foam producers bother with this intermediate step. To avoid guessing, Block
height is usually averaged by taking the maximum center height of the crown
and subtracting % inch.
The amount of unwanted excess of foam
that has been poured into a mold either intentionally or unintentionally. See
, and packing
A switch actuated by movement of a diaphragm or bourdon
tube located near the pump in the flow
circuit and arranged to cut off the power to the pump drive motor. This device
protects the fluid circuit against damage from over pressurization. Other types
of Overpressure protection devices are available such as pressure relief valves
and blowout disks. See cut-off switch.
A term in urethane
which refers to the particles of atomized material that hit outside the intended
target area. With some equipment, formulations
and environmental conditions this may amount to as much as 50%of the material
sprayed; with others it may be as low as 5%. Usually the finer the atomization
the smoother is the surface of the foam
applied, but the higher is the percent of overspray
The addition of oxygen to a compound or the reduction
An acronym which is a registered trademark representing
one of the polymeric isocyanates
that are used in the manufacture of one shot
rigid foam, particularly flame resistant formulations
where high char strength is desired. PSI-the abbreviation for pounds per square
inch but does not indicate if the reading is by gauge or is absolute. PSIG-the
abbreviation for pounds per square inch, gauge. Absolute readings at sea level
would be 14.7 pounds per square inch. higher than gauge readings.
An expression of the degree of acidity or alkalinity
of a substance. Neutrality is pH7 - acid solutions being under 7 and alkaline
solutions over 7. Accurate pH meters are commercially available.
Package (d) Unit
A unit that needs only to be supplied with services and
filled with chemicals to make foam. The term is somewhat ambiguous, since it
is used to refer to small individual metering
and mixing units as well as to giant continuous
process lines complete with all accessories required to make the final
A term which can refer either to mold
or to the seal around the rotating shaft of some pumps or mixers.
An overall description given to an apparatus on a slab
production line that cradles one or
more rolls of paper, allows the paper to unwind over a special framework at
the proper tension, shapes the paper to the form desired, smoothes and flattens
the paper on the conveyor, and may or may not unwind the paper from the foam
Paper Shaping Device
That portion of a paper
that shapes the paper into the desired form and holds it
there until the foam
has enough strength
to support it without assistance.
A system of mechanically peeling the paper from the slab
as it moves past the unwinding
station. It generally consists of a spindle at each side of the conveyor driven
by a device producing constant torque rather than speed, and a roller device
beneath the conveyor driven by the same or similar type drive motor. It may
or may not be included under the general heading of paper handling system in
a machine description.
Refers to a system for the preparation of urethane
in which all of the isocyanate
is prereacted with a small part of the polyol
at some time prior to the introduction of the final components
into the mixing chamber
prereacted intermediate (partial
) may be prepared in a very complex manner in expensive equipment
or it may just be poured together in a tank or bottle, mixed briefly and allowed
to stand overnight. Foam prepared from a partial
can have superior properties to one shot
but is usually more expensive due
to the extra processing. Ratios between the two major components
vary from about 50/50 to about 70/30. This is also known as a quasi-prepolymer
Peak Rise Point
A term used to describe foam
in which the cell structure
so uniform that when it is peeled or split to a thickness of as little as 1
millimeter, no noticeable variations in cell
or structure appear. To achieve this goal stringent control of all
mechanical, chemical, and environmental variables is usually required.
A term used to describe a mechanical cutting device that
is capable of slitting or peeling a continuous sheet of foam, as little as 1
millimeter in thickness, from the circumference of a round log shaped piece
of foam. The technique is similar to that used to peel veneer from a wooden
log. The cylindrical foam
logs are sometimes
trimmed from long Blocks
of foam, with
a square cross section that have been bored to accept the mandrel of the peeler.
More recently techniques of foaming continuous round sections have been developed.
Percent Set Test
The increase in length, expressed in a percentage of
the original length, by which an elastic material fails to return to original
length after being stressed for a standard period of time. In flexible foam
this generally is related to loss of height of a cushion in service.
The rate at which a liquid or gas can penetrate into
or through a material, in this case foam. It is primarily of interest for water
vapor or carbon dioxide gas permeability
of rigid foams
used in insulation
since either material
reduces the effectiveness of the foam. See water
A somewhat ambiguous term applied, in the USA, to a wide
variety of small cushions used in many different type Applications
It usually is preferable to qualify the term with a more descriptive adjective
such as head or sleeping pillows
for those used on beds to support heads, decorator or throw
for those colorful and variously shaped cushions used to decorate
furniture, etc. The original definition in the USA was limited to "something
that cushioned and supported the head" but recently the meaning has broadened,
perhaps in response to an awareness that Europeans used the word in a much different
A rotating mixing blade generally characterized as having
a straight, relatively sturdy, central shaft parallel to the direction of liquid
and a series of smaller,
round, square or hexagonal shaped "pins" mounted on the central shaft at right
angles to the central shaft and generally perpendicular to the liquid flow.
There are many variations of this involving pin mounting angles other than 90
degrees (different diameter pins, different quantity of pins, different spacing
between pins, etc). It is usually classed as a low
(n.) One of many high polymeric substances, including
both natural and synthetic products, but excluding the rubbers. At some stage
in its manufacture every plastic is capable of flowing, under heat and pressure,
if necessary, into the desired final shape. (a.) Made of plastic; capable of
under pressure or tensile stress.
A change in dimensions of an object under load that is
not recovered when the load is removed; opposed to elastic deformation.
Various chemicals used as Additives
in a formulation
serve to increase the flexibility of the foam
structure. In flexible foam they can be used in some formulations to give a
softer, more rubbery feel to the foam. In rigid foam they can be used to overcome
extreme brittleness or friability where heat distortion is not critical.
A term used to describe the flat spot in a compression-deflection
curve of a flexible foam that can be classified as 'boardy' or possessing 'boardiness
A 'wide plateau' would indicate a very boardy foam. See IFD
A term better known as air drive or air actuated. There
are three different types classed as linear actuating pistons, vane type rotary
shaft and piston type rotary shaft. Properly designed into a mechanism, air
drives can be useful. As an example, pneumatic drive of a traversing mechanism
provides two design features that are not present in any other type: pneumatic
cushioning of the reversal to avoid metal fatiguing shock waves, and complete
elimination of the heat produced by the absorption of the energy involved in
reversal of the mechanism (the hot air is immediately discharged).
Tears or rips in the foam, approximately the size of
a man’s hand, having smooth walls that are separated from each other. They may
occur in the side or the interior of the foam
A measure of the specific viscosity
of a fluid. It is measured by the force required to move one plate in relation
to another plate when the space between is filled with the fluid. A material
with a viscosity of 1 poise requires 1 gram of force to move the plate 1 centimeter
in 1 second. Since most of the fluids used in urethane
foam have viscosities that vary with the temperature, any statement regarding
fluids must be qualified with the temperature of the hid at which the data was
which is 1/1OOth of a poise, is more commonly used in the foam
industry particularly since water is approximately 1
at 20 degrees C and thus provides a physical comparison with
which we are all familiar.
A term used by some to describe the polyethylene cone
with different orifice
sizes that are used to control the diameter and shape of the liquid stream
being discharged from the mixing chamber
of a urethane foam
Is one of the families of compounds that can be prepared
with reactive hydroxyl groups
and thus can be used as a polyol
preparation of urethane
is a large family and a wide variety of compounds can be used. As a family,
these compounds are characterized by the presence of -C-O-groups in the molecule.
This type of bond is more susceptible to attack by water (hydrolysis) than is
the single oxygen present in the polyether
type. Polyester polyols
more expensive, in the USA, than polyether
Is one of the families of compounds that can be prepared
with reactive hydroxyl groups
and thus can be used as a polyol
preparation of urethane
is a large family and a wide variety of compounds can be used. As a family,
these compounds are characterized as having ether groups -C-0-C-in the molecule.
This type of molecular joint is less susceptible to hydrolysis than the type
characteristic of polyesters
. In general
polyethers are less expensive than polyesters
in the USA.
A high-molecular-weight organic compound, natural or
synthetic, whose structure can be represented by a repeated small unit, the
mer; e.g., polyethylene, rubber, cellulose. Synthetic polymers are formed by
addition or condensation polymerization of monomers. If two or more monomers
are involved, a copolymer is obtained. Some polymers are elastomers
Is generally used to refer to those isocyanates
containing products that consist of a mixture of isocyanate
compounds containing more than two isocyanate
groups in the molecule. This type is being widely used in the rigid foam
field where good heat resistance and high char strength is required. This type
heat generation than with 'pure' diisocyanates
hence there is less tendency for scorching of the foam.
The chemical reaction during which larger molecules are
being created by the joining of smaller molecules. If polymer
chains are linked by chemical bonds to form a network, a cross linked polymer
results. Flexible foams possess a lightly cross linked structure while rigid
possess a highly cross linked structure. Proper choice of the base
chemicals and the formula
in a product with any desired degree of flexibility or rigidity.
Is a chemical compound with more than one reactive hydroxyl
attached to the molecule.
The product resulting from premixing
many of the compatible minor ingredients into the polyol
component. This is usually done in order to reduce the final number of components
required to be metered and introduced into the mixing head and to improve the
of the compounding when some
of the minor ingredients would be difficult to meter individually because of
very small quantities or very high viscosity
This also allows time to mix some materials that are difficult to mix in the
short length of time available in the final mixer. This product is also called
' and 'premix
Polyurethanes (Also termed Urethane Polymers)
A term synonymous with cell
. It is primarily used in Europe.
An ambiguous word that is defined as meaning 'easily
carried'. Many advertising brochures carry descriptions of machines labeled
as 'portable' that can only be 'easily carried by a fork lift truck. To avoid
misunderstanding it has been suggested by some that portable be used in connection
with anything that can be easily carried by one man, and that the word moveable
be used for anything requiring 2 or more men.
Small, lightweight cutting machines for foam
or fabric that have 8 inch to 24 inch long high speed reciprocating blade(s).
These machines are usually quite versatile and are convenient to use in cutting
out complex shapes that have been ordered in quantities too low for economical
A term which refers to those pumps that are so designed
that substantially all of the material displaced from the suction side of the
pump is delivered to the outlet side of the pump. In other words internal recirculation
is at a minimum and what little there is, is constant over a fairly wide range
of conditions. In normal practice some limitation in use is necessary. Under
some conditions, a pump that is positive
with a 1000 cps
may slip rather badly with 100 cps
material. Under other conditions, a pump that is designed to be positive
with a 1 cps
may transfer enormous quantities of energy in the form of heat to material of
The ability to control the flow
rate of a particular fluid to an Accuracy
of approximately 1% of the total flow
regardless of temperature or pressure fluctuations downstream from the metering
device. This is difficult to achieve in normal practice at all times under any
conditions. It can be achieved economically if certain design rules and limitations
of use are practiced. There is a certain amount of ambiguity in the term since
many piston pumps can be classified as positive metering for total quantity
delivered, while the amount delivered per second may vary, and many gear or
vane pumps can be positive metering both for total quantity delivered and for
quantity per second delivered.
A term which refers to the condition in which two or
more fluid streams
are positively metered
with respect to an absolute standard and are maintained in an exact ratio with
each other continuously.
A term used to describe the condition existing when the
rate is changed in two or more fluid
circuits simultaneously while still maintaining positive
. For Accuracy
tracking is normally stated as a plus or minus variation from a standard flow
level and for a specific viscosity
A term normally applied to the period of curing after
product has been handled by removal
from the mold or conveyor. In some cases accelerated curing (usually oven heating)
is practiced in order to achieve some predetermined level of physical properties.
Depending on the formula
and the final
product desired, this may be accelerated post-cure in an oven at temperatures
between 250° and 300° F. or a room temperature post-cure over a period of several
days. The term sometimes is used ambiguously to cover what is otherwise called
'. See pre-cure
. post-cure oven-an
oven in which post-curing is accomplished. To be completely effective the product
to be post-cured in an oven must be placed in the oven with as little temperature
loss as possible while in transit from the manufacturing area.
A term applied to the practice of reshaping a piece of
by the Application
of a combination of heat and pressure after it has been cut to the proper dimensions.
It is usually performed on flexible slab foam
when pleasing or intricate curves are desired, and the investment in foam
equipment would not be practical.
The process of encapsulating or imbedding a device by
pouring a casting
compound into a cavity
in which the device has been fixed and curing the compound in place, As a result
the device is imbedded completely in a plastic
, either solid or foamed. The
compounds are usually thermosetting
and vacuum may be used with the solid polymers
in order to avoid entrapped gases.
A term referring to the practice of pouring a liquid
into a cavity and having it foam, fill the cavity, harden and cure
without having to remove it from the cavity and without having to shape the
product by cutting or sawing. The term is sometimes used interchangeably with
, but potting is used more to
refer to the solid or non-foamed pour-in-place.
The pattern formed by a liquid steam being deposited
in a mold, in a cavity or on a conveyor. This is often quite critical.
A mixing head designed only to dispense liquid mixtures.
The position at which the mixed liquid is deposited on
the conveyor in a slab process system.
A conveyor having the moving surface powered by a drive motor. The term is used
to differentiate between this type of conveyor and other non-powered types,
such as roller conveyor
A term normally applied to the time interval between
pouring the chemicals into a mold and the time the product can be removed from
that mold without damage to the product or the mold. This is also sometimes
called 'stripping time' or "handling time'.
An oven in which pre-curing is accomplished. This can
be supplied with heat from any source that will raise the temperature of the
mold quickly without damaging the foam
product or the mold. This is a critical part of molding
process and is usually the limiting factor in molded foam
production rates. Types of ovens in use range from hot air circulating heat,
powered by steam, gas, oil or electricity, to microwave powered units. Some
are equipped with powerful 'fast heat' radiant units to increase the internal
mold temperatures more rapidly.
A term normally applied to the technique of bringing
molds or cavities to the desired temperature level prior to pouring. This is
a fairly critical factor and must be accomplished with reasonable Accuracy
quality control. Even the so-called 'cold
' process requires some mold heat control for quality standardization.
The oven in which pre-heating is accomplished.
A term often used synonymously with masterbatch
or polyol mix
to indicate the mixture
resulting from blending many of the minor ingredients in with the polyol in
an effort to reduce the final number of components
or to allow more time for mixing or blending those chemicals that may not be
readily miscible in the short period of exposure to the final mixing. See polyol
A term used to indicate tanks that are used for making
batches of premix
separately from the
machine and also those tanks on the machine that are used in the premix flow
Specially modified cutting devices that round off the
corners of Blocks
that are to be peeled so that very little time of the actual peeler
is wasted in this time consuming operation. Actually, the major portion of the
peeling cycle is spent in installing the 'logs
and attaching the first amount
of peeled material to the wind-up roll. Prepeeling may reduce this wasted time
by as much as 50%.
A chemical intermediate used at times in the production
foam. It is normally manufactured
by prereacting all of the isocyanate
material with part or all of the polyol
This can be carried out in a special reactor kettle or in a normal blending
tank and is a means of building some properties into the final foam
product that would not be there ordinarily. See total
A technique used to secure more exact chemical metering
when froth is to be produced. Usually special valves are installed between the
pumps and the mixing head and the pressure generated by the pumps is increased
to the value that would be present during the frothing
pour by using this special valve to throttle the liquid flow. Metering or calibration
of the liquid flow
rates and ratios is
accomplished while the pressure is at the artificially high level in order to
minimize the effects of internal pump slippage on calibration
The valves are left in this position during operation. Pressures of 70 to 150
psig are normally maintained in the mixing head during frothing
in order to keep the fluorocarbon 12 in its liquid phase during the mixing operation.
A term used to describe the condition existing in an
'on-off' fluid metering
the pressure during the 'on' cycle is exactly the same as the pressure during
the 'off' cycle. This condition is normally required for best quality foam
production, as most commercial foam
have rubber hoses in the circuit plus places that could trap gas and act as
accumulators. Under these circumstances if the pressure were permitted to change,
of material could occur immediately after switching 'on' (mix cycle) which would
cause an imbalance in the stoichiometric ratio of the chemicals, and poor quality
' during at least a portion of the cycle would result. Generally the
shorter the 'on' time, the more critical is the pressure balance, depending
on the design and capacity of the impeller
and mixing chamber
A valve located somewhere in the return line between
the mixer and the tank and used to help in balancing pressures. In some cases
this valve is built into the mixing head, and in others it is separate and located
on the tank. For some materials, particularly isocyanates
the construction of the valve is important, and it should be of a type that
does not accumulate small particles. In most cases a filter
is installed just prior to the valve to ensure more trouble free performance.
The closer the valve is to the mixing head, the better is the performance. regulators
are sometimes used for pressure
instead of valves.
A technique used to gain more positive control of metering
when a water-thin (1 cp) viscosity
liquid must be metered at extremely small flow
rates. This situation is encountered often when total
systems are used for filling very small cavities. With this technique
a special needle valve or pressure regulator
is installed in the flow
circuit of the
system between the metering
pump and the mixing head and as close to the mixing head as possible. A back-pressure
(between the valve and the pump) of at least 5 psig is maintained at all times.
Very small inner diameter metering
must be used in the mixing head to keep the system liquid full at
all times, but they must not be so small as to cause the pressure to rise during
the 'on' cycle.
A device for measuring and indicating pressure. It is
not safe or practical to operate a urethane
machine without accurate pressure
gauges in all flow
Are reactive groups present in certain polyol
molecules. Primary alcohol groups react faster than secondary alcohol groups.
Usually, the higher the percentage of primary alcohol groups in the formulation
the less catalyst
required for curing. The term 'primary hydroxyl groups' is often used interchangeably.
A term used to describe the master drive motor and speed
controller used with interlocked or master-slave systems.
Factors in the chemicals, the machine or in the environment
that could change in such a way as to affect the quality of the foam. More than
50 have been identified and labeled in the production of flexible slab
. Among these factors are such things as the control over metering
stability, temperature of the chemicals, catalyst
type and level, etc.
A term used by those concerned with testing work to describe
the point at which an elastic modulus
changes from a straight line function. This would normally indicate the elastic
of the material beyond which permanent damage to the material structure
would result. puddle-the practice of pouring all the mixed liquid material into
one spot in a mold or cavity with no attempt to distribute the material.
A term occasionally used to describe a metering
A mixing blade designed to positively move the liquids
being mixed through the mixing zone
and through the discharge orifice
by means of the force exerted by the pumping action designed into the mixing
A shortened form for refrigerant 12 which is a neutral
(non- trademark) name sometimes used to describe fluorocarbon 12, (dichlorodifluoromethane)
a very low temperature boiling
commonly used as a frothing
An abbreviation used to represent Rubber Manufacturers
Association Test which is an indentation load deflection test used to rate cushions
for load carrying ability.
The term is rarely used, the preference being for IFD test. The Test Method
is described in ASTM
A term which refers to the large, irregular, normally
elongated gas pockets usually found in frothed foam. Their size can be minimized
by careful manipulation of the mixing
pressure, the percent of R-12 used in the formula
the type of chemicals used, etc. They are also called worm
The ability to change and regulate the ratio or proportion
between 2 or more fluid components
. This introduces versatility to a machine, enabling it to be used with several
. A fixed
machine can be built that will work with only one formula
under precise operating conditions, but these are rarely requested. raw materials-a
term often used to describe the chemical ingredients used in manufacturing urethane
foam. The term is generally applied to the chemicals as received from the chemical
manufacturers prior to any premixing
Manufacturer-(Also Called Materials
A manufacturer of one or more of the basic chemicals
used in the urethane foam
A general term that can be used for any of the raw materials
or intermediates used in the manufacture of foam.
The balance between the relative reaction rates of gas
generation (blowing) and gelation (polymerization). This is quite important
in the production of urethane
as a formula
with too rapid generation
of gas may cause collapse
while a formula
with too rapid a gelation
will become closed celled in the case of flexible foams, or may tear
apart by internal cracks in the case of rigid
. See blowing reaction, gelation reaction and polymerization
for further information.
Is a term used to describe the process of adhering small
particles of foam
back together again to make a saleable cushioning product. Several processes
are available, some using latex adhesives, others using a foaming adhesive based
on the urethanes
, some requiring heat
or to dry, others curing at room
temperature, some producing an inferior product, others producing a product
superior to 'virgin foam
' in many
ways. A typical Application
is for rug underlays.
A seldom used term describing a device used for spreading
the mixed liquids in a uniform pattern in molds or on conveyors. They are also
called traversers or spreaders
A term which refers to the practice of continuously pumping
the metered fluids back to the machine
during the "off" portion of a foam
production cycle. The 'on-off' valving in the mixing head serves merely to divert
this continuously metered flow
the mixing chamber
or back to
the machine tanks
. There are three
different degrees of recirculation defined as follows: Full
all the way to the mixing head and back with little or no
volume of non-recirculated material between the diverting valve and the mixing
, partial or short recirculation in which the diverting valve is
located at some distance from the mixing
, resulting in a relatively large volume of non-recirculated material
between the valve and the mix chamber, and non-recirculate in which there is
no return line at all and the pump is either stopped during the 'off portion
of the cycle or the pump is equipped with an internal bypass that operates when
a valve is closed in the line between the metering
pump and the mixing head.
A fluid control device usually consisting of a housing,
a spring loaded diaphragm and a means for adjusting the spring tension. This
can be used to control either the upstream or downstream pressure.
A term sometimes used as a synonym for hysteresis
or sometimes as a synonym for the settling
that occurs after peak foam
A drive motor, usually for a mixing head, that is located
at some distance from the mixing head itself and transmits power by means of
a flexible shaft drive or some other method.
A powerful pleasant smelling chemical which is added
to a formulation
to mask the unpleasant
odors sometimes associated with Amine
or even the polyols
on occasion. There are a wide variety of scents available and if used properly,
reodorants can perform a valuable service.
The ability to produce the same result at repeated intervals.
This is a very important consideration in buying chemicals or machinery, since
lack of reproducible control over any production variable can result in the
production of poor quality foam.
A measure of the 'rubberiness' or elasticity of the product,
in compression. One of the methods for measuring this is the 'Ball
Foam that has a very rapid recovery from extreme compression
and a fairly linear increase in resistance to compression per inch or centimeter
A term used as a general term describing the unsaturated
or monomers used in the paint
industry, in particular those in the polyester
family. It is occasionally applied to the polyols
used in urethane
The process of removing residual membranes or cell
from the foam
structure so that only a skeletal web-like network remains. There are several
techniques involved and there are many patents in the field.
Very low density
foams characterized by a three-dimensional
skeletal structure of strands with few or no membranes between the strands,
containing up to 9701, or more of void space. They are made by treating an open-cell
structure with a dilute aqueous sodium
hydroxide solution under controlled conditions so that the thin membranes are
dissolved, leaving the strands substantially unaffected. Ultrasonic vibrating
is sometimes used to assist the solution process. These foams are used in filters
for air-conditioners, automobile carburetors, air cleaning systems; and in acoustical
panels, humidifiers and various household products.
Is the study of flow
and deformation of matter.
Like structures formed at the joint between adjacent
bubbles in a foam
which becomes open-celled.
The ribs are usually reinforced by the remains of the cell
in good quality foam.
which can be classified as having a firm stiff behavior and can be said to exceed
their elastic limits
greater than 10%.
There are many other plastic
than polyurethane foam. The most common of the other types are polystyrene
foam, epoxy foam, polyethylene foam, phenolic foam, and urea-formaldehyde foam.
may be thermoplastic
The time interval between the liquid mixture being poured
into the mold and the completion of expansion of the foaming mass.
A usually non-powered conveyor that is constructed of
a series of tubes suspended at each end by a shaft and bearings which are fastened
to a rail on each side. The rails are parallel to the direction of movement;
the axis of the rollers are perpendicular to the direction of movement, but
the surface of the rollers rotates in the direction of travel when a product
is pushed on top.
A slang word referring to the appearance of the froth
being discharged from a letdown nozzle
When all variables are in proper adjustment, the discharging material often
takes on the round slightly fuzzy appearance of a manila rope dangling in air.
A term sometimes used to describe a mixing blade or impeller.
The time during which the foam
machine was actually in operation to make foam. Recirculation time is excluded.
An abbreviation used to refer to the Society of Plastic
Engineers. This is a national organization of engineers working in the plastics
industry. The executive office is located at 65 Prospect Street, Stamford, Connecticut
06902. many regional chapters cover The SPE Journal is the official
An abbreviation used to refer to the Society of the Plastics
Industry. This is a national organization of companies and individuals in the
is oriented towards developing industry standards and test methods, their Applications
and promotion of plastics
as well as maintaining the proper public image.
A composite structure intended to serve as a structural
building panel for walls, roof, floors, etc., posed of at least three pieces,
a low density
case (a rigid foam) and
two outer skins
or surfaces. The major
portion of the load bearing is intended to be accomplished by the two outer
surfaces, while the inner core serves primarily to maintain the outer surfaces
completely in parallel. schematic diagram-a drawing that illustrates the design
and relationships of a machine, circuit or process in an abstract or symbolic
manner bearing no relationship to its physical appearance or size.
The technique of producing special cut shapes from Blocks
or sheets of flexible urethane foam
by variably compressing certain areas of a foam
and cutting the foam
while it is deformed. Foam soap dishes and variously shaped cavities that are
used as shipping containers for light bulbs, glasses, TV tubes, etc., are among
the many that can be made in this manner.
A term which normally refers to waste from a urethane
manufacturing process that cannot
be used. This term is often used to describe usable trim cuttings also. See
. scraped surface heat exchanger-See
heat exchanger, scraped surface.
A shortened form of scraped surface heat exchanger package
Sealed Mixing Heads
A mixing head' with a built-in rotary seal on the impeller
drive shaft and possibly an '0' ring seal around the mixer housing so that mixing
under pressure, such as in frothing
be accomplished without leaking the mixed materials into the bearing housing
or other areas. For best results, rotary seals must be lubricated. The best
arrangement appears to be a DOP circulation system. Another system, primarily
useful in continuous processing, is the polyol
Devices used to heat-seal sheets of foam
together so that the 1000 to 2000 yd. rolls used by the laminated fabric industry
can be built up, The sealers are usually mounted on the frame of the peeler
between the cutting bar and the wind-up roll. Sealing is usually accomplished
by a combination of pressure and a heated resistance wire.
used for padding in chairs on which a person sits. They may be separate from
the main frame of the chair or sofa or form an integral part of it. A Back
, on the other hand, is leaned on rather than sat on.
A term used in Europe with the same meaning that 'seat
' has in the USA.
Are reactive alcohol groups (CHOH), present in most polyol
molecules. They are less reactive than primary alcohol groups. See
primary alcohol groups
The ability of a mixing device to so completely expel
the mixed materials after an 'on' cycle that repetitive cycles can be accomplished
without any clogging. In actual practice this is difficult to attain on an absolute
basis since it is influenced by the cream
of the formulation
the length of the 'on' time, the length of the 'off' time, etc. Because of this
some form of solvent
is normally required either after each cycle or as long as after every
four hours of use.
The ability of a foam
to stop burning after it has been started burning in a controlled manner. One
of the tests used to determine this is Test Method ASTM
D 1692. Caution must be used in applying the results of this test to actual
, since the sample is
unconfined during the test, and flammable decomposition products are free to
Self Skinning Foam
A term which refers to the relative ease of the daily
manufacture of foam
using a specific formulation
If all operating conditions must be exactly controlled in a very narrow band
in order to make acceptable quality foam, the formulation
is said to be sensitive or critical. If acceptable foam
can be made day after day with only average control over the variables, the
is said to be tolerant.
The normal loss in height of the continuous flexible
at a point just past peak rise.
This loss of height occurs as the cell
walls rupture and is a sign that the foam
will be open celled. If the loss of height is excessive, splits may occur. If
the loss of height does not occur the foam
will normally be closed cell.
Cutting devices that can produce almost any special shape
desired from a Block
or sheet of foam.
Some examples of this type saw are shoulder pad cutters, scoop cutters, convoluting
cutters, breast pad or hip pad cutters, circular cutters and bolster
cutters. sharp cut-off-a term which describes the ability of a mixing head to
stop the flow
of mixed liquids abruptly
as soon as the valving mechanism cuts the flow
of the chemicals into the mixing chamber
'No After Drip
' also describes the
same condition. This condition is greatly dependent on the material viscosity
and is almost impossible to achieve with low viscosity formulations
The ability of a flexible foam
to resist laterally applied forces (applied parallel to the foam
surface). This has a bearing on the comfortability of the foam
when used as a cushion and its abrasion resistance.
The ability of a rigid foam
to resist deformation when subjected to laterally applied forces (parallel to
surface). This is of interest
particularly in sandwich panel
work. The Test Method is described in ASTM
An ambiguous word used sometimes to describe cratering
and sometimes to describe windows
Short (re) cycle valving-the valves or valving device
used to recirculate the separate components
on a short recycle system. They are usually similar to the valves used for full
recirculation, but not always. See recirculation
The total amount of mixed liquid dispensed from an 'on-off'
during an 'on' cycle.
A term which refers to the reproducibility
of the total quantity delivered by an 'on-off'
in a specified time interval. An Accuracy
of plus or minus 0.25% can be achieved with good quality equipment, depending
on the formula
and the size of the shot
As a general rule the shorter the time 'on', the greater the Accuracy
A term which describes the total time spent 'on' and
'off' in a single unit of operation. Usually the time 'on' and the time 'off'
are both identified. For example, 5 seconds 'on' and 10 seconds 'off' would
completely describe a shot cycle.
Shot Cycle Timer
A timing device used for automatic control of a shot
cycle. See shot size timer
Shot Size Timer
A timing device used to control the duration of the 'on'
time only. It has to be manually actuated for each 'on' cycle and has no control
over the 'off cycle. The term is often used interchangeably with shot
A mechanical device used to tear or rip foam
pieces into very small pieces which
can be used for filling dolls, pillows
etc., or for rebonding
products. They are also called grinders
, etc. See crumb
A term which describes the loss in size that occurs occasionally
products. Exothermic temperatures
encountered in the interior of many foam
products is often between 250° to 300° F. At this temperature the gas in the
bubbles is exerting a higher pressure than it would at room temperature. In
order to withstand this loss in pressure the cell
walls must break, in the case of flexible foam, or the cell
walls and structure must be rigid enough, in the case of rigid foam, to accept
the pressure difference without collapsing. If a flexible foam
has closed cells
, it will shrink
when it cools. If a rigid foam
quite reach a truly rigid structure before cooling, the cell
walls will either rupture, or, if the material is somewhat plastic
will shrink in size. It is sometimes
used as a synonym for settling
flexible slab process.
Conveyors that are used as moving sidewalls on a continuous
process conveyor. This is particularly applicable to rigid slab manufacture
when the formulation
has a tendency
to gel prematurely and as a result exert sufficient pressure on non-moving sidewalls
to lock the slab in place.
in the foam
with widely separated edges.
Horizontal tears or rips in the side of the foam
. These splits are either horizontal
to the plane of the foam
conveyor or slightly
angled. They may appear intermittently or continuously along the side of the
slab. The edges of the tear are not separated to any large extent, and consequently
the tears are often difficult to see. Two common causes are an excessive speed
of the blowing reaction in relation to the gelation reaction and too steep an
angle of rise.
Complex chemicals formed from a combination of silicon
and organic groups to form polymers that exhibit surface active properties when
used in urethane foam
. In general these compounds
add stability to the liquid foaming mixture so that drainage (collapse
of bubbles due to extreme loss of bubble wall thickness) is retarded and flow
ability of the mass is increased. There are many different varieties that can
be used; some contribute to fine uniform cell
, while others increase the irregularity of the cell
A term which describes the higher density
outer surface of a foam
integral skin foam
. The skin usually is the result of surface cooling. It
can be eliminated by maintaining the outer surface of the part at the proper
Foam made by the continuous pouring of mixed liquids
on a conveyor generating a continuous loaf
for as long as the machine is operating.
This type of foam would generally be classed as free
or unconfined, although fixed side guides give the loaf
a generally rectangular cross section with a slightly rounded top. A few installations
have a top conveyor to aid in flattening the top surface so that a more nearly
rectangular cross section is produced.
A term which in the USA refers to the separate, generally
soft and fluffy, cushion used to place under the head while sleeping, In other
countries very hard pillows
may be used
for this purpose.
A term used in rigid foam
spraying to refer to the sagging of the foaming mixture that sometimes occurs
during spraying of a vertical surface. Among the many causes of this are slow
gelation, excessive buildup, lack of proper temperature control of the chemical
or the target surface,
A term used to refer to rubber like compounds that have
no internal cavities or gas bubbles.
An insoluble Additive
to a urethane
that remains a finely divided solid even after blending into the mixture. It
is often used to add weight to a formula
while reducing the formula
add firmness to the foam
or greater viscosity
to the liquid mixture. Generally tensile strength is reduced by this type filler
A substance, usually liquid, used to dissolve another
Solvent Blown Foam
A term which refers either to the rinsing of the mixing
with a solvent
or to the
equipment required. This can be accomplished by many methods ranging from a
squeeze bottle, through manual
valving to completely automatic types. In some cases an air flush or purge follows
the solvent flush to ensure that no solvent remains in the mixing
when the next mix cycle is initiated. Methylene
is the most commonly used cleaning solvent.
Solvent Flush Cycle
A term used to describe a solvent
, air flush cycle (or solvent cycle only), and indicates the time of
each. For example, a typical solvent flush cycle might be 5 seconds of solvent
followed by 10 seconds of air. The cycle may be initiated by push button and
controlled by timers so that it automatically shuts off and resets for the next
push button actuated cycle; it may be automatically initiated by timers or manually
initiated by opening a valve. The timers are normally adjustable so that more
or less air or solvent can be forced through the mixing
Solvent Flush Timers
Timers used to control the quantities of solvent
and air dispensed during a solvent
by controlling the duration of the 'on' cycle of a valving device
or pumping mechanism.
A term which refers to the durability of material exposed
to solvent. It is usually measured by determining the percentage weight increase
after a specified number of hours of immersion in the solvent. A 10 to 15% increase
in weight is usually not too objectionable.
any material divided by that of water at a standard temperature, usually 4'
C. Since water’s density
is nearly 1.00
in g./cc. and specific
gravity are numerically nearly equal.
A splattering which sometimes occurs when the mixed liquid
is poured into a mold or onto a conveyor. The spattering or splashing may cause
the formation of large bubbles which can be trapped in the rising foam, showing
up as large cavities or voids in the foam
A rather ambiguous term used to describe many different
products. It is most often used to
describe 'Blown Elastomers
particularly those with high load bearing and higher densities (8 pounds per
and higher). It sometimes
is used to refer to an open celled product, and sometimes to a completely closed
Spray Mixing Head
A mixing head in which the primary cause of mixing is
the atomization and turbulence created in the mixing
by one or more high velocity air jets. Mixing may be external to the
and completely dependent on the
air turbulence for mixing, or internal and partially dependent on impingement
onto the interior walls of the mixing
. See external mix
A device to assist in placing a uniformly distributed
layer of mixed foam components
into a mold or onto a conveyor prior to foaming in an effort to minimize flow
of the expanding mass during foaming. A typical device of this type consists
of a horizontal track supported at each end on which a moving carriage rides.
The mixing head is mounted on the carriage, and the carriage is driven back
and forth by a drive mechanism. The drive mechanism can be linear or rotary
, mechanical or
A term normally used to refer to those Additives
that assist in maintaining the quality of the foam
in use such as anti-oxidants, ultraviolet absorbers, acid absorbers, etc. Occasionally
it is used to refer to foam
such as the silicone compounds
that add stability to the semi liquid expanding mass. stannous octoate-one of
the more commonly used organotin catalysts
particularly for flexible one shot
One of the major reasons for its preferential use is that it is usually destroyed
or converted to a less active form by the exothermic heat of the reaction, minimizing
degradation in the final foam
of the stannous octoate type. It is approximately 1/2 as active,
A term which describes the loss in load-bearing properties
of a foam
sample under constant compression.
Steel Rule Die
A device used for stamping pr 'clicking
out intricate or simple shapes from sheets of foam
or other soft material. They are manufactured by imbedding narrow bands of sharp
edged steel into a wooden back plate in the pattern desired. The sharp edge
of the die is placed against the surface to be cut; the die is then hit a sharp
blow with a mallet or with the platen of a 'clicking
press which drives the die through the material and cuts out the desired pattern.
The practice of interconnecting drive motors and pumps
with a multi path gear box so that several different 'fixed or 'step' outputs
are available rather
than the more usual infinite variation between fixed upper and lower limits.
A term which refers to the relationship of the various
combining weights of several interacting chemicals. For example, it takes approximately
10 grams of TDI
to completely react with
100 grams of standard flexible foam
and approximately 1 gram of water
to completely react with 10 grams of TDI. A stoichiometrical balance is achieved
when 100% of all the chemicals used in the reaction are consumed in the reaction.
In the urethane
industry this stoichiometric
balance is termed 'having an index of 100.' See index
Mixing blades or impellers
that have parallel sides or cylindrical shape as opposed to tapered sides or
A term which sometimes is used to describe the flow
of liquid of one of the components
in the formula
or the circuit through
which it flows. For example, the flow
from the nozzle
may be called the 'TDI
stream'. Also in slab foam
'upstream' would be 'against' the flow
of foam, and 'downstream' would be 'with' the flow
Lines and/or streaks of cream colored liquid extending
upstream from the cream line
the clear liquid dispensed from the mixer during the slab foam
process. They may be from 0 to 24 inches or more in length but are generally
kept between 2 and 6 inches long by careful regulation of the angle of rise,
the conveyor speed, the flow
quantity or balance, etc.
Streamers are an important guide to quality control, and if all variables are
properly controlled, will always appear the exact same distance downstream from
the mixing head with the same formula
. Different formulas may have different distances. Excessively long streamers
will generally forecast the presence of splits; excessively short or non existent
streamers will forecast undercutting
and the presence of flow
lines and/or side
and top cracking.
Due to the viscoelastic nature of plastics
the amount of force or stress necessary to produce a given amount of deformation
gradually decreases during the time the stress is applied. This decay of stress
at a constant deformation is called stress relaxation.
With rigid foams
the time between pouring the mixed liquids into the container and the time that
long 'strings' of tacky material can be pulled away from the surface of the
when the surface is touched with a
wooden spatula or even with the fingers.
A term generally used with spray foam
to describe the surface
on which the foam
A European term usually synonymous with the American
' which is 12 inches x
12 inches x 1 inch. This measurement of volume is used as a convenient frame
of reference for pricing both rigid and flexible foam
stock (cut slab foam
Surface Active Agent
Surface To Volume
A means of differentiating between cavities with the
same volume but vastly different shapes. For example, a cube with a volume of
1 cubic foot
would have a surface
area of less than 1000 square inches. The same volume, distributed so that the
cavity was only 1inch thick. would have a surface area of over 3000 square inches.
The two different shapes of cavities require different techniques and formulations
in order to exactly fill them with equal amounts of foam.
The momentary increase in relative flow
rate that occurs in a fluid metering
when the pressure drops from a previously higher but stable level
to a lower and again stable level. With 'on-off'
, this can occur at the instant of diversion of flow
from recycle to mix if the operating pressures under both conditions have not
previously been balanced. Theoretically the surge would not be of significant
quantity if the metering system
had no flexible hoses or places in which air or gas could be trapped, but unfortunately
it is usually necessary to carefully balance the pressure to avoid off ratio
spots in the product.
A special hose to pipe fitting or adapter that is so
constructed that one permanently attached end freely rotates, permitting easy
assembly and disassembly of parts. Occasionally swivel adapter and fitting are
used interchangeably. See swivel fitting
A special hose or pipe fitting that is so constructed
that one permanently attached end freely rotates, permitting easy assembly and
disassembly of parts. See swivel adapter
The property exhibited by a blend of some materials,
having a greater effectiveness or chemical activity as a mixture than would
ordinarily be expected from the sum of their independent abilities or activity
levels. Some combinations of urethane
would appear to have
A rather ambiguous term used to describe almost any combination
of mechanical parts or chemicals that have some relationship to each other.
For example, the metering mechanism is often described as the 'metering
' which includes just the mechanical parts. A 'froth system', on the
other hand, usually includes the chemicals within its scope and might even refer
to the chemicals by themselves. A 'complete system' is sometimes used interchangeably
with 'complete package
' to indicate
everything needed. to produce foam
chemicals, process know how
A common symbol for tolylene diisocyanate
particularly the 80-20 isomer
it is sometimes used for other blends, Occasionally it is misused to represent
resulting in some confusion since many of the so-called 'crude or undistilled
' are not related to TDI
at all other than by the attached NCO
Is a symbol for one of the Amine
used in foam
. The actual name of
is N,N,N1,N1- tetramethyl-l,3-butanediamine
making it easy to understand why the symbol is used.
A device used to indicate the speed of some mechanism,
usually the number of revolutions per minute of a pump or impellers
Under specified operating conditions, tachometer readings can be accurately
related to flow
rate. The combined information
from tachometers, temperature gauges, pressure
data, etc., provides
the necessary background on which to base troubleshooting judgments. tachometer
indicator-the dial or meter portion of a tachometer device that actually displays
The time between pouring the liquid mixture and the time
that the surface of the foam can be touched with a spatula or a finger without
sticking. This is a very difficult interval to relate positively to other factors
since it is often influenced by environmental temperature and humidity. See
also string time
The condition of the surface of a foamed object, particularly
in the atmosphere, during
which any object touching its surface will stick to the surface. This is normally
a stage in the cure
through which foams
pass on their way to final cure. See tack-free
and string time
A name given to a conveyor on the discharge side of an
in-line cutoff saw that is designed to take away the cut pieces of foam
at a slightly faster rate than that of the main foam
conveyor in order to prevent fouling the saw blade.
A mixing blade or impellers
characterized as having nonparallel sides coming closer together towards the
discharge opening. Symmetrical impellers
of this type could be called cone shaped with the inlet being the wide end of
the cone and the outlet being at the narrow part of the cone. See
straight sided impellers
The ability of a piece of flexible foam
to resist deepening a cut already made in the foam
The special technical language often used by science
or engineering trained personnel which has meaning only to others of similar
The process of bringing the object or surface to a specified
operating temperature. It is normally used to indicate a passive operation such
as storing drums of chemicals in a room with a controlled temperature between
70° and 75° F., allowing the chemicals to acquire the temperature of the room
over a several day period, with no attempt at agitation of the drum contents.
Foam samples prior to testing are temperature conditioned.
That portion of a temperature sensing device that displays
the information on a dial or meter.
A combination of temperature sensing element, temperature
display and thermostat. This is used for controlling the temperature of one
of the urethane foam
in a metering
through control of the operation of a heat exchanger.
The unmixed or layered condition often encountered in
particularly the larger ones. Under some conditions warmer material returning
to the tanks after passage through a heat exchanger will slide out on top of
the cooler material without mixing, resulting in a warm strata at the top and
a cold strata at the bottom. Under other conditions the warmer material will
channel right through to the pump suction, leaving the bulk of the colder material
in the tank and out of the flow
tensile strength-normally expressed as the pounds per square inch of force required
to stretch a foam
sample to the breaking
point. See elongation
An Amine catalyst
of the type useful in urethane foam
reactions, characterized by a molecular structure in which the nitrogen is directly
connected to organic radicals only and not to hydrogen atoms as in ammonia.
The tertiary Amines
are generally more
than the primary
or secondary types of Amines
The equipment or devices necessary to carry out the Test
Methods. It should be kept in mind that although some degree of testing is necessary
for quality control, most of the tests necessary cannot be performed with any
degree of Accuracy
within two or three
days of the production run of foam. In most cases this foam
would already be distributed to the customers so that for practical purposes
quality control starts with the foam
equipment and is directly dependent on it. Many manufacturers have so called
'quick tests' which they use to exAmine
the uncured foam. These are relative rather than absolute but can be quite useful.
Ability of a material to conduct heat; physical constant
for quantity of heat that passes through unit cube of a substance in unit of
time when difference in temperature of two faces is 1 degree.
The production of a partially expanded fluid from the
mixer by means of heating the component(s) containing fluorocarbon 11 to levels
far above the normal boiling
point, while maintaining them under pressure from the tank through the mixing
. The sudden reduction of pressure at the discharge nozzle
allows the blowing agent
to boil, and thus partially expand (or froth) the discharging liquid mixture.
This is apparently a useful technique for working with high viscosity
or high elastic component
that are otherwise
difficult to keep mixed after discharge and prior to the cream
The analysis of a foam
sample by graphically recording the weight loss of the sample at different temperatures
through the decomposition point or zone. See differential
A material which is capable of softening or melting at
elevated temperatures without degradation so that cooling of the material restores
it to its original condition.
A material that is cured or transformed by elevated temperatures
into a solid condition from which it does not change, upon reheating, until
it reaches the decomposition point. Most urethane
materials are thermosetting materials (e.g. flexible and rigid
). Certain urethane elastomers
and fibers are thermoplastic
Refers to the ability of a fluid to be jelly-like or
semi-solid at rest, but reverting to a liquid on being agitated or stirred.
Some degree of thixotropy helps a spray formulation
to achieve greater thickness in a single pass.
Roll Paper Feed System
A system of paper supply for a slab foam
conveyor consisting of a single bottom sheet of paper with two separate side
sheets. The three roll type is usually tied in with a paper unrolling or removal
system of the constant tensioning type. Although this system is more expensive
than the single roll type, it usually pays for itself through fewer wrinkles
and less foam
damage. In addition there
is greater freedom of paper supply when producing extremely wide Blocks
of foam, since paper roll widths required are up to 4 or 6 feet less than that
required for a single roll system. See paper
Any one of several devices that have been calibrated
to have some direct relationship with flow
rate such as tachometers
, speed adjusting
A term which applied to metering
machines and mixing heads generally refers to the maximum flow
rate that can be metered and mixed with all pumps at their maximum delivery
or with some specified formulation
This can be a very misleading statement because of the diversity of formulation
ratios for urethane
foam. For example,
a machine with maximum flow
rate of 30
pounds per minute with a 50-50 ratio for a 2 component
may only be able to deliver
15 to 16 pounds per minute of a total
with a 97/3 ratio.
Under some conditions of extreme high viscosity
the maximum flow
rate may not be achieved
within the pressure or pump suction limitations of the machine.
A specified allowance for deviations in weighing, measuring,
etc., or for deviations from the standard dimensions or weight. Also applied
to foam formulations
is said to have tolerance
if it can reproduce good quality product from day to day despite variations
in raw materials, environmental conditions or small metering
A term used to describe a weakness that can occur in
the joint area between multiple pours of foam
in a single, usually thin, high rise cavity. The name comes from the characteristic
shape of the joint shown in a vertical cross-section of the foam. Under certain
conditions severe cracking can occur in this area during exposure to -15° F.
top surface of a foam
slab that extend
across the width of the conveyor. The edges of the cracks
are widely separated and the inner surface of the crack is fairly smooth because
they occur during a liquid phase. This is usually associated with undercutting
In contrast the edges of a split are usually close together and the inner surface
is rough or jagged because they usually occur later during the final stages
The process of shortening the tack-free
of the top skin
foam by heating it with radiant, steam or hot water heat. It is highly
desirable that all tack (or tackiness) should be gone by the time the slab foam
is cut, handled and stacked.
Top Cure Oven
The oven or device used to effect top curing of foam
Thin cushioning pads used as the top layer of an automobile
seat to provide a good 'feel' to the seat.
Total Flow Rate
A term which generally refers to the method of filling
the foam machine
or of keeping them filled. The most usual technique is to use air
operated bung pumps installed in the chemical supply drums. These can be either
manually valved at the machine tank or connected in conjunction with a level
control device which automatically causes shut off of the transfer pump at the
proper time. The term also is used to refer to the elaborate pumping network
installed in the factories of large foam
producers who buy their chemicals in bulk. The purpose of the network is to
transfer the bulk chemicals to the proper machine
at the proper time.
The chemical name of one of the more common Amine
used to make urethane
foam. It is one of the most active.
A term which refers to the small pieces of good quality
that are removed from the crude Block
operations. Trim consists of bottom, top, and side skins
plus odd length or thickness leftovers. With proper management many profitable
items can be manufactured from this trim material. See also scrap
The percentage of the total good foam
produced that is not sold directly after the primary cutting operation but must
be further cut or converted or reduced in price in order to be saleable. The
percentage may be by weight or by volume. Trim losses as low as 3% and as high
as 45% have been reported.
Two Phase Material
A term which generally refers to a composite material
such as a fiber or pellet filled plastic
in which the composite has superior
properties to either of the starting materials.
The overall coefficient of heat transfer. This value
incorporates all the factors involved in the transfer of heat from one area
to another, including boundary layer transfer and any or all 'IC' factors. 'U'
values are generally used in calculating heat transfer of a structure in a particular
environment; whereas 'IC' factors are generally used for single components
of a structure.
UV Stabilizer (Ultraviolet)
Any chemical compound which, when admixed with a resin
selectively absorbs UV rays. ultraviolet-zone of invisible radiations beyond
the violet end of the spectrum of visible radiations. Since UV wavelengths are
shorter than the visible, their photons have more energy, enough to initiate
some chemical reactions and to degrade most plastics
A term used in foam
slab work, particularly flexible foam, to describe the appearance of the foam
front when the angle of rise is so great that the streamers
have disappeared underneath the rising foam. This can result in flow
lines, side and/or top cracking and the entrapment of large bubbles in the center
of the foam
A term used in pour-in-place
work to describe the condition of not having completely filled the void or mold
with foam. Either not enough chemicals were used, or the foam failed to expand
the expected amount.
A term used by some companies in place of 'crude' or
A term for years used as the common name for a chemical
more properly called ethyl carbamate (a biological poison); the term is now
used to refer to the product of a reaction between a chemical containing reactive
groups on its molecule
and a chemical containing reactive hydroxyl
on its molecule. These compounds are, for the most part, biologically
inert. The compounds are called polyurethanes
Since the name refers to the molecular joint between the monomer, many different
chemicals can be used as the building Blocks
or 'monomers' with the final product still being known as a urethane
compound or polymer
That portion of the mixing head that is responsible for
diverting the various flows simultaneously between recirculate and operate.
These may be very simple, manually operated individual valves or more complex
automatic devices that may divert from 2 to 6
The practice of catching in individual cups the output
of all fluid streams
an indefinite time period in order to check the ratio between fluid streams,
but not the flow
rate per minute.
Flow Rate (Throughput) Control
The ability to be able to change the flow
rate of any or all components
usually within a fixed minimum and maximum limitation. See fixed flow
problem, under some conditions of metering
and mixing machine operation, in which pressures are exactly balanced (see pressure
). This can be caused by unequal velocities of the
due to extreme differences in viscosity
or quantity. Under these conditions one material will reach the mixing-pumping
zone before the other and will be expelled from the mixing
before enough of the other component
has been blended in to bring the mixture back on ratio. This problem is more
likely to occur with extreme differences in viscosity between the various components
and can often be corrected by changing the diameter, length or direction of
discharge of the metering
bandsaws in which the portion of the blade that is used for cutting is in the
vertical plane. This type of saw is usually characterized by large moving tables
that carry the foam Blocks
past the cutting blade.
A term which generally refers to those pour-in-place
operations in which the cavity to be filled is extremely long in its vertical
dimension (height) in comparison to its thickness and generally is higher (vertically)
than its width (horizontally). This would give the cavity a large 'surface
to volume ratio
'. This is also called a high-rise Application
A term sometimes used to describe a special fitting on
the suction side of a rotary pump that is used to isolate the pump from the
tank by means of a rubber coupling or bushing so that stresses on the pump casing
are reduced. This is particularly important when the pump is mounted directly
beneath the tank.
A term often used to describe foam, particularly flexible
, that has not been processed
in any manner other than cutting to shape. It is a means of differentiating
between rebonded, laminated or pieced together foam
and the original or 'virgin' material.
A term which generally refers to the flow
characteristics of a material which is not completely rubber- like, not really
rigid and not readily fluid.
The resistance of a fluid to being fluid (or flowing
readily). For example, a low viscosity
material would flow
readily from a container
on being poured, while a high viscosity material would only pour slowly from
a tipped container. See centipoise
The scope of viscosities, between stated maximum and
minimum limits, that can be handled properly by a metering
machine, pumping system, pump, mixing head or other specified item. Usually
viscosity range is coupled with flow
range and under some conditions can cause confusion, since a particular machine
may not be able to achieve maximum flow
rate with maximum viscosity
or may not be able to achieve stated Accuracy
at the minimum flow
rate with the minimum viscosity material.
A term generally used to describe any fluid more resistant
than water. The degree of viscousness
) is generally expressed
in centipoises in the foam
clarification, see poise
A term occasionally used as a synonym for pour-in- place.
When used it generally refers to filling structural cavities rather than the
filling of molds.
A term used with rigid foam
to describe the percent by weight of water pickup on submergence of a specified
sample under a specified depth of water.
Water Blown Foam
Foam in which the gas for expansion was generated by
the reaction between water and an isocyanate
bearing material. See blowing
for further clarification.
(WVP)The rate of transfer of water vapor through a film
of the polymer
. This is normally determined
by an indirect test method on cast films of the solid polymer
rather than on the foam
itself. This is
sometimes called water vapor transmission (WVT).
An instrument which is utilized to subject articles to
accelerated weathering conditions, e.g., rich UV source and water spray.
A term sometimes used to describe scattered large bubbles
that occasionally appear in large Blocks
of slab foam
that are otherwise uniform
in cell structure
walls in flexible foam
that are unbroken
or ruptured but intact, which interfere with free air movement through the foam
structure. Generally a high proportion of windows, as indicated by the shiny
or glittering reflection of light from a cut surface, indicates a foam
tending towards closed cells
consequently possibly rather poor in some physical properties. Usually a reduction
in the organotin catalyst
relation to the Amine catalyst
level will reduce the incidence of windows. There are other processing factors
which can also affect their presence.
. This is the point in compression or tension loading of a sample beyond
which permanent damage to the structure of the sample results. Before this point
complete elastic recovery will occur. Commonly rigid foam
is defined as that foam
having a yield
of less than 10% (compression or elongation
The force required to bring a specified sample of foam
to the yield point
. The force is
usually stated in pounds per square inch.