Glossary

Accelerated Test

Any test procedure where specified conditions are intensified to theoretically reduce the time required to obtain a given property deterioration. Usually charting mechanical property (tensile, tear, and/or elongation) loss over time.

Abrasion Resistance

The fundamental ability of a material to withstand surface rubbing, erosion, or scraping. Generally, polyurethane foams display high abrasion resistance.

Absorption Coefficient

Value expressed as a decimal representing sound absorbed by foam at a specified Hzlevel; used to report acoustical absorption capability of foam.

Additive

A material used to modify the properties, processing, or end use of a base polymer. The amount of additive used is usually expressed in parts per hundred (by weight) of the major resin in the polymer formulation. Examples: germicide, FR, anti-stat

Adhesion

The physiochemical state by which two surfaces are permanently held together by interfacial forces, which may consist of covalent forces, mechanical interlocking, or a combination of both.

Aerosol

A suspension of extremely fine liquid droplets in a gas, usually air.

AFI Filter Tester

Air Filtration Institute test equipment utilized to evaluate a filter media such as reticulated polyurethane foam for its ability to filter particles from a moving air stream. It has the capability of determining pressure drop, efficiency and dust holding capacity.

Air Flow, Dow Method

A measure of the ease with which air will pass through a foam sample (Test Method ASTM D3574-01). Amount of air expressed in cubic feet per minute, that can be drawn through a 2" x 2" x 1" foam sample at .5 inch of water pressure differential.

Air Flow, Frazier

See Frazier Air Permeability

Aliphatic

A term used to describe a chain-like molecule made up of carbon and hydrogen atoms without the presence of benzene rings. Contrasted with these are aromatic compounds, such as benzene, which have ring structures.

Ambient

Indicative of the surrounding environmental conditions around a specimen, such as temperature, pressure, etc.

Ambient Noise

The sound pressure levels associated with a given environment.

Anechoic Chamber

A room in which all of the boundaries are highly absorptive so that sound may propagate in all directions without being reflected off room surfaces. The name "anechoic means "without echo". It is used to solve sound problems.

Anisotropic

Exhibiting different properties when tested along axes in different directions, e.g., parallel to foam rise as opposed to perpendicular to the foam rise. Polyurethane Foam is slightly anisotropic.

Antioxidants

Materials added to a foam formulation and/or components to improve the resistance of the foam to oxidative discoloration type reactions.

Antistatic

Electrical property range of 109 - 1014 ohms/square

Antistatic Agents

Additives that can impart a degree of electrical conductivity to foam and thus increase the rate of dissipation of electrostatic charges.

Anti-Static Flexible Polyurethane Foam

Foam that has been modified with electrically conductive materials to prevent static electricity buildup or promote static dissipation. It is used primarily in packaging applications, such as electronic components.

Aromatic

Loosely, a term used to describe molecules that include at least one benzene-like ring, e.g., C6H6

ASTM

The abbreviation for American Society for Testing and Materials, a non-profit corporation organized in 1898. It is considered a world leader in the development of voluntary standards for materials, products, systems, and services. ASTM D-3574-01 is the Standard Test Methods for Flexible Cellular Materials.

Attributes

According to SPC, qualitative data that have only two conditions: acceptable and non-acceptable.

Auxiliary Blowing Agents

Compounds used to produce gases to expand, or blow flexible polyurethane foam during production. Most auxiliary blowing agents are low temperature boiling solvents, such as chlorofluorocarbons, methylene chloride, methyl chloroform, acetone, hydrochlorofluorocarbons, and isopentane. See Montreal Protocol.

Backbone

The long chain portion of a polymer. May have pendant groups or reactive end groups.

Ball rebound test

A method for comparing the resilience of flexible foams per ASTM D-3574-01 Test H. A steel ball of specified mass is dropped from a fixed height onto a foam sample and the height of the ball's rebound is recorded. The rebound height is divided by the original height to give a percentage.

Barrier Material

A barrier placed between a cover fabric and filling materials to slow heat transfer and flame spread to the filling material

BTU

British Thermal Unit. The quantity of heat required to raise the temperature of one pound of water from 60o to 61o F at a constant pressure of one atmosphere.

Block

See Bun.

Blowing Agent

A gas, or substance capable of producing a gas, used in making foamed materials.

Blowing Reaction

One of several reactions occurring during formation of foam. A chemical reaction resulting in the release of carbon dioxide.

Board Foot

A standard measure of foam that equals one square foot of material one inch in thickness.

Boardiness

A term describing foam that feels stiff and not flexible and yet is still in the flexible foam category. A typical foam of this type would require a small force to cause an initial deflection and very little more force to deflect to about 50% of its thickness.

Bond Strength

The unit load applied in tension, compression, flexure, peel, impact, cleavage, or shear required to break an adhesive assembly, with failure occurring at the interfacial plane of the bond. Also the degree of attraction existing between atoms within a molecule.

Boston Chair Test

Boston Fire Department test method to measure performance of flexible polyurethane foam padding materials when exposed to a fairly severe flaming ignition source. This test is a full-scale composite test. Ignition source is four double sheets of newspaper crumpled inside a paper grocery bag.

Bottoming-out

The characteristic of some flexible materials to support an initial load with a small amount of deflection but virtually collapse under any additional load; a function of density and IFD.

Box Foam

Generally, any foam of approximately 1 cubic foot or larger volume produced in the laboratory using custom-built semiautomatic mixing equipment.

Buffed

Flexible polyurethane foam pieces that have been shaped or contoured by removal of foam using abrasive or grinding methods.

CPC

Continuous Platform Cutting. A post-process used to alter the surface of foam to impart desired properties; used especially in roll goods. See SMT

CpK

Capability index which accounts for process centering and defined as the minimum CpU or CpL. It relates the scaled distance between the process mean and the closest specification limit to half the total process spread.

Calibration

Refers to checking the accuracy of a measuring device. For example, the weighing of carefully timed dispenses of chemicals from the metering ports of the mixing head in order to set an exact component ratio or an exact throughput of all chemicals.

California 117 Foam

Flexible polyurethane foam filling material or padding that will meet the requirements of the California Bureau of Home Furnishings' Technical Bulletin No. 117. See Flammability Test Methods. Often referred to in abbreviation as "CAL117."

California Technical Bulletin 117

California Bureau of Home Furnishings test methods and requirements for open flame and cigarette resistant materials used in residential upholstered furniture construction. Cal-117 is a small-scale component test. Ignition source is either an open flame gas burner as specified by Federal Test Method Standard No. 191, Method 5903.2 or smoldering cigarettes meeting the cigarette specifications DOC FF4-72. Foam usually must pass both parts.

Capability (Cp)

When the average +/- 3X standard deviation is within the specification tolerance.

Catalyst

A substance that affects the rate of a chemical reaction, but is unaffected by the reaction.

Cause and Effect Diagram

A diagram showing all the factors that affect a process. Used to identify possible causes of a problem; shows how causes interact.

Cell

The 12-sided structure (dodecahedron) formed by the nucleation and growth of bubbles within the reacting liquid. The individual cavities in the skeletal structure of foam formed by the nucleation and growth of bubbles within the reacting liquid.

Cell Count

In foams, the number of individual cells per unit area.

Cell Membrane

The thin, intact film that forms the walls in a foam cell. Also called cell windows. Membranes are removed during the reticulation process.

Cell Size

The average diameter of cells in the final foam based on RAM measurement methods. The average diameter of the cells in the fully reacted flexible polyurethane foam, measured in inches. Also called Cell Diameter.

Cell Stabilizer

A substance that helps the formation of fine, uniform cells in foam by inhibiting the coalescence of small bubbles.

Cell Window

See Cell Membrane

CFC

Chlorofluorocarbons. Compounds comprised of carbon, fluorine, chlorine, and hydrogen that are used as auxiliary blowing agents in polyurethane foams. The Montreal Protocol on Substances that Deplete the Ozone Layer was adopted in 1987 as an international treaty to eliminate the production and consumption of ozone-depleting chemicals.

CFC-Free Foam

Flexible polyurethane foams that have been made without the use of chlorofluorocarbons as auxiliary blowing agents.

CFD

Compression Force Deflection. A measure of the load-bearing ability of a foam. It is the force exerted against a flat compression foot larger than the specimen to be tested. The value is typically expressed at 25%, 40%, 50%, and/or 65% compression per ASTM D-3574-01 Test C. Also called Compression Load Deflection or CLD.

Chemical Resistance

The fundamental ability of a polymer to withstand chronic exposure to acids, alkalis, organic solvents, and other corrosive chemical environments.

Clickability

Tested by using an ASTM D-3574 tensile shaped die to die-cut a foam specimen from a 1" thick piece of foam at room temperature. An experienced lab technician will rate the specimen using the FXI system. Rating scores are reported for "initial" and after 1 minute "recovery" as follows: Good = 3 whereby the foam part and/or sheet has sharp clean edges without crimping or compression. Fair = 2 whereby the foam part and/or sheet has slight crimping or compression. Poor = 1 whereby the foam part and/or sheet has moderate crimping or compression and may be entirely welded. Parameters that affect clickability: temperature and humidity, condition of die (quality of steel, sharpness of die, material used inside the die cavity to control compression); configuration of the die (complicated vs. simple pattern); settings and condition of die press; condition of backer board; thickness of foam material, foam type (polyester or polyether).

Clickability, FXI Policy

FXI will certify to the click rating evaluated in the laboratory at ambient temperature and humidity with an ASTM D3574tensile die on a 1" thick piece of foam. FXI cannot guaranteeclickability under every condition listed above. However, FXI will provide technical support to help solve customer die-cutting issues.

Closed Cells

A foam structure in which each individual cell has intact cell membranes so that there are no open passageways for airflow.

CO2 Blown Foam

Foam in which all the gas for expanding the reaction mix comes from the reaction of water with isocyanate. Sometimes called an all-water blown foam. Also, liquid CO2 can be added in a special process as a blowing agent.

Coarse Cells

Large cells averaging no more than 20 to 30 cells per linear inch.

Coefficient of Friction

The coefficient of friction between two surfaces is the ratio of the force required to move one over the other to the total force pressing the two together. If F is the force required to move one surface over another and W is the force pressing the surfaces together, the coefficient of friction is u=F / W. Also known as COF.

Colorant

Dyes or pigments added to impart color to the foam.

Common Cause

A source of chance variation that is always present in the process

Component

A separately metered stream of liquid or solid that will be introduced into the mixing head.

Compression Lines

Densification of polyurethane foam blocks due to bending fresh material at very acute or very obtuse angles. Lines usually appear towards the bottom of the bun or load where the foam bends closest to the surface. Can also be vertical when caused by squeezing fresh block with a crane or forklift clamp.

Compression Load Deflection (CLD)

See CFD

Compression Set

A measure of the deformation of a foam after it has been held compressed under controlled conditions. The standard conditions are 22 hours at 70°C. Per ASTM D-3574 Test D foam is compressed to a thickness given as a percentage of its original thickness. Compression set is most commonly expressed as a percentage of original thickness, i.e., a 10% compression set means the foam recovered 90% of its original thickness.

Conditioning

The act of subjecting a test specimen to standard environmental and/or stress history conditions prior to testing.

Conductive

A material is considered conductive if its range of resistivity is100 - 105ohms/square

Conductivity, electrical

The reciprocal of volume resistivity; the conductance of a unit cube of material.

Contact Angle

The contact angle is the angle between the surface of a drop of liquid and the solid surface upon which it rests. If the contact angle is< 90°, the liquid has an affinity for the solid. If the contact angle is >90°, the liquid is repelled by the solid. In capillary tubes, a contact angle of > 90 degrees will cause the fluid to rise in the tube. A contact angle of > 90 degrees will cause the fluid to drop in the tube.

Continuous Slab

The production of a seamless loaf of foam by laying down a uniformly distributed layer of mixed materials on a conveyor belt moving beneath a mixing head at such speed as to form a stable rising front of foam.

Control Chart

A graphic representation of a characteristic of the process; includes a central line, upper and lower control limits and process values plotted on the chart. Shows how variable the process is and at what level the process is performing.

Control Limits

A line on a control chart that represents the maximum variation that could be reasonably expected if only common causes were present. NOT related to a specification

Conventional Foam Machine

Equipment designed for cellular foam production where the mechanism to move the foaming material away from the mixhead consists of a conveyor and sidewalls that are at one continuous angle, typically 0 - 5o . This angle can be changed depending on the foam being produced.

Convoluted

A fabrication process in which flexible polyurethane foam is cut while compressed non-uniformly to produce a surface with a contoured texture. This texture gives the foam a different surface feel, or apparent softness.

Copolymer

A high-molecular-weight substance containing several types of repeating structures.

Corona Discharge

The flow of electrical energy from a conductor to the surrounding air or gas. The discharge is produced by high voltage, > 5000 V, resulting in a characteristic pale violet glow.

Correlation Chart (Scatter Diagram)

Used for investigating the relationship between two variables; demonstrates whether a relationship does exist. A simple way to approximate a regression line.

Creep

The degree of compression or height loss that occurs when a flexible foam cushioning material is subjected to a static load over a defined time period.

Cross-Linker

Molecules that tie chains together to form branched chains or polymer networks.

Cross-Linking

The formation of chemical bonds between different polymer chains.

Crushing

Usually a mechanical or vacuum-assisted procedure to open the closed cells of a cold-cure or high-resiliency foam.

Cure

To change the physical properties of a material by chemical reaction, which may be condensation, polymerization, or vulcanization; usually accomplished by the reaction of heat and catalyst alone or in combination, with or without pressure.

Cure Oven

An oven into which foams are placed in order to achieve a desired level of accelerated cure.

Cure Time

The length of time required for sufficient reaction completion to develop a desired level of polymer strength and dimensional stability. Can be from 8 to 120 hours, formulation dependant.

Custom

Foam which has many cell membranes still intact, Contrast with reticulated foam.

Dead Foam

Foam that has a low resiliency and only slowly regains its original shape after deformation.

Decibels (dB)

A unit of sound intensity

dB A

Sound intensity level measured on the "A" weighting network of a sound level meter. This "A" network approximates the frequency response of the human ear.

Deflect

To compress, usually by a specified amount or percentage.

Delamination

The undesirable separation of one or more layers in a laminate caused by failure at the adhesive interphase.

Densified

A material that has been made more dense by permanently compressing a unit mass into a smaller volume. See SIF Felt or Scotfelt

Density

Density is the weight per unit volume of the foam normally expressed in pounds per cubic foot (PCF), or kilograms per cubic meter (kg/m•). The general range of polyether flexible polyurethane foams is 16 to 64 kg/m3. This density is not a measure of firmness as it is with latex rubber foams. Density is an important, factor, however, in that for a given load-bearing requirement, higher density foam generally gives better quality and performance. ASTM D-3574-01 Test A.

Density Gradient

Variations in density within a foam sample due to phenomena such as heat loss, settling, surface wetting, or shearing of the foam during pouring. Most foams show a density gradient from the geometric center to the outer skins.

Deterioration

An undesirable permanent change in the physical or chemical properties of a polymer evidenced by an impairment of these properties.

Dielectric Heat Sealing

A sealing method in which materials, such as films, are heated rapidly by dielectric heating, causing adhesion.

Diisocyanate

A compound containing two isocyanate groups per molecule. A class of monomers used in preparing polyurethane.

Dip and Nip Coating

A coating process whereby foam is immersed in a vessel containing a solution, suspension, or heated fluid coating material, then withdrawn, squeezed between rollers and subjected to heat or drying to solidify the film deposit.

Discoloration

The gradual yellowing of foam due to a photochemical reaction. It is faster in sunlight than in artificial light, although it occurs in both. Foam may also discolor as a result of thermal or various chemical events.

Dissipative, Static

Electrical property range of 105 - 109 ohms/square

Dodecahedron

A geometric figure (polyhedron) having twelve surfaces or faces. A polyurethane foam cell is a dodecahedron.

DOE

Design of Experiments is the arrangement in which an experimental program is to be conducted, and the selection of the versions of one or more factors or combinations of factors to be included in the experiment.

Dry Heat Aging

A procedure in which the physical properties of flexible foams are determined after purposely exposing samples to a specified elevated temperature at ambient relative humidity.

Durability

As applied to flexible foams, the term refers to how well foam retains its load bearing capacity with use. Most measures of durability are done with laboratory-scale tests that often have imperfect correlation to real world experiences.

Durometer

An instrument used to measure hardness of elastic materials. Durometer is also used to reference a scale of hardness; i.e., a low durometer implies a soft material

Elasticity

The ability of a material to return to its original shape after removal of a load. Also referred to as memory or recovery.

Elongation

Percentage of original length that a standard sample of foam will stretch before the breaking point is reached. ASTM D-3574-01 Test E.

Energy Management

Semi-rigid foams designed for impact, sound, or vibration energy absorption.

Exotherm

The heat liberated by the foam-producing reactions. This heat accelerates the foaming and curing processes.

Fatigue

A measurement of the loss in load bearing under simulated service conditions, generally expressed as a percentage load loss. The two most common fatigue test are Static Fatigue and Dynamic Fatigue, depending on the application. ASTM D-3574-01 Test I. A thickness loss can also be measured.

Fatigue, Dynamic

There are a number of roller-shear tests that use the same basic equipment. A roller, longer than the foam width, is rolled back and forth across the foam. The roller is mounted in an offset position to impart ashearing action. Tests vary in use of constant deflection settings. ASTM D-3574-01 Test I2, I3, and/or I4.

Fatigue, Static

In this test, the foam is compressed to 25% of its original thickness for 17 hours at room temperature. IFD (Indentation Force Deflection) losses are calculated as percentages of original values. ASTM D-3574-01 Test I1.

Felt

Per FXI, permanently compressed flexible polyurethane foam. See SIF Felt

Felted

Flexible polyurethane foam that has been densified by time, heat, and compression for use as a vibration dampening, fluid management, or shock absorbing material.

Fine Cell

A term used to describe foam of 80 or more pores per inch.

Firmness

Regarding felt, the thickness ratio of unfelted base stock to felted foam. Thus, Firmness 4 felt has a 4-to-1 compression ratio.

Flame Lamination

The practice of bonding flexible foam to another material by melting one surface of the foam with a flame and quickly pressing it to the second material before the melted material resolidifies.

Flame Retardant

A substance purposely added to inhibit the spread of a flame applied to the final foam.

Flammability

Is a measure of the burning length, time, or rate of foam. There are many methods and specifications for testing the flammability characteristics of foam.

Flex Fatigue

The loss of physical properties of a foam undergoing continuous flexing of a specified magnitude, duration, and rate. ASTM D-3574-01 Test I3.

Flexible Polyurethane Foam

A lightweight cellular material resulting from the introduction of gas bubbles into a reacting polymer matrix. A flexible foam is one that does not rupture when a 20 x 2.5 x 2.5 centimeter piece is wrapped around a 2.5 centimeter diameter mandrel at a uniform rate of 1 lap in 5 seconds in an ambient temperature of 15-25°C.

Flow Diagram

A graphic representation of the steps in a process.

Fluorocarbon

The general family of fluorinated hydrocarbons that find use as auxiliary blowing agents.

FMEA

Failure Mode and Effect Analysis. To provide a graphic representation of the elements, components or tasks associated with a process. Used to understand where things can go wrong in a process.

Foam

A lightweight cellular material resulting from the introduction of gas bubbles into a reacting polymer matrix. According to ASTM D 1566-82, a flexible foam is one that does not rupture when a 20 x 2.5 x 2.5 centimeter piece is wrapped around a 2.5 centimeter diameter mandrel at a uniform rate of 1 lap in 5 seconds in an ambient temperature of 15-25°C.

Foam Fatigue

The loss of physical properties of a foam article in use. The most noticed problem is the softening of cushions.

Formulation

The list of chemicals to be used in the preparation of a foam.

Frazier Air Permeability

ASTM D 737 Textile Test Procedure - The Frazier permeability test unit measures the pressure drop caused by the foam as it resistance to the constant air flow. The aperture of the test area is 2.75" ( 70 mm ) in diameter. A clamp is used to prevent the air from leaking around the edge of the foam specimen. The speed on the motor is increased until the airflow reading is steady at 0.5" on the inclined manometer. The inches of water level is read on the vertical manometer. The chart provided from the manufacturer converts "/H2O to ft•/ft• x minute. The units are reported as ft3 / minute / ft2 of foam, abbreviated as cfm. ASTM D 3574, Test G is used as the surface area of the D 737 test is greater; 6 in• vs. 4 in•

Frequency (Hertz)

The number of complete vibration cycles per second. Frequency is expressed in Hertz (Hz) or cycles per second (cps).

Friable

A term used to indicate the crumbling, flaking, or powdering of a foam when the surface is rubbed. Usually refers to rigid foams.

Gel

An intermediate state of cure in thermoset reactions in which the material goes from a liquid to a soft, rubbery mass.

Gelling Reaction

One of several reactions occurring during formation of a foam. That reaction between polyols, crosslinkers and isocyanates leading to the formation of larger molecules, increased viscosity, and eventually to a high-molecular- weight macro or urethane molecule.

Glass Transition Temperature

A characteristic temperature at which, for example, a foamed plastic becomes flexible as a result of the onset of segmental motion of the polymer chains. The temperature where a material changes from a glassy (hard) state to a more rubbery (flexible) state.

Graft or Polymer Polyol

Polymers with active hydroxyl groups that have other organic groups or polymers "grafted" to the polyol molecule. These grafted organic compounds serve to reinforce the strength or modify other properties of the flexible polyurethane product. Polymer polyols used for making urethane foams typically contain a styrene / acrylonitrile copolymer as the graft.

Guide Factor

The ratio of 25% IFD to density expressed in whole numbers. Guide factor is useful in determining the relative firmness of foams with different densities. It is also used to compare the economy of foams. The higher the guide factor, the more economical the foam because you get a firmer foam with a lower density.

Hand

A subjective description of the feel of the foam as the hand is rubbed lightly on the surface of the foam. If the foam is harsh or rough to the touch, it is described as having poor hand. A foam with good hand has a velvety feel. See CLD and COF

Hardness

See CLD and IFD.

Hardness Index

A term used in some specifications for the 50% IFD value.

Head

Short for Mixing Head.

High Resiliency

High-resiliency (HR) molded polyurethane foams are based on the reaction of higher-molecular-weight polyols (4,500 - 7,000), either with polymeric isocyanates, with blends of distilled and polymeric isocyanates, or with 80/20 TDI or 65/35 TDI. The term "high resiliency" results from the improved resiliency of these foams compared to that of more conventional hot-molded or slabstock foams. "HR" formulations also are characterized by higher catalyst concentrations (several different catalysts are often used to develop optimum processing and physical properties) and the addition of special silicone surfactants. HR molded foams have several advantages: 1. Their sag factor, or modulus (ratio of 65%IFD/25%IFD) is superior to that of conventional hot molded foam typically greater than 2.40. 2. The amount of energy required to accelerate foam cure and development of physical properties is considerably lower than that required in hot molding. 3. These foams can meet the federal standard MVSS 302 flammability test more easily than conventional foams.

Histogram

A bar graph displaying a number of observations or measurements within a range. Also a picture of the distribution showing the scatter of the data; used to look at patterns.

Humid Aging

An accelerated aging test conducted under various combinations of high humidity and temperature.

Hydrolysis

The breaking down of the chemical compounds by reaction with water. In the case of polyurethanes, the chemical compound is a polymer that depends on a high molecular weight for its physical properties. Any reduction in its size, primarily due to its reaction with water in a high heat environment, will reduce the physical properties of the polyurethane and result in a weakening of the polymer network. Hydrolytic degradation of ester urethane foams could result in the formation of diethylene glycol, adipic acid or low molecular weight polyester polyurethane fragments. In comparing polyesters and polyethers, polyesters are affected more readily by hydrolysis than polyethers, which tend to resist hydrolysis by a factor of ten.

Hydrolytic Degradation

The degradation of flexible polyurethane foam by hydrolysis or disassociation by water and heat under conditions of constant exposure. The humid aging test method was developed to attempt to measure the effects of hydrolytic degradation

Hydrophilicity

The affinity of substances (in this case polyurethane foams) for water. In general, polyether foams are not as hydrophilic as polyester foams.

Hydrophobicity

The lack of affinity of substances (in this case polyurethane foams) for water. In general, polyether foams are more hydrophobic than polyester foams.

Hydroxyl Equivalent

The number of grams of sample required so that one gram equivalent weight of hydroxyl (17.008) will be present in the sample.

Hydroxyl Group

The combined oxygen and hydrogen radical (-OH) that forms the reactive group on polyol molecules.

Hydroxyl Number

This number indicates the number of reactive hydroxyl groups available for reaction. It is expressed as the number of milligrams of potassium hydroxide equivalent to the hydroxyl content of one gram of the sample.

Hypoallergenic Specifics

There is no official government definition for this term; therefore, the most appropriate terminology is: "a product less likely to cause allergic reactions". "HYPO" means "less than", and hypoallergenic means only that the manufacturer sells a product that is less likely than others to cause an allergic reaction. Although some manufacturers do clinical testing, others may simply omit perfumes or other common problem-causing ingredients. Number one cause for allergic reactions of products touching the skin is fragrance; next is preservatives. Contamination is the third serious concern, from poor handling practices or exposure to chemicals. All of these concerns play a part in the decision as to whether a company makes a claim of "hypoallergenic". This information was obtained from the FDA Consumer Magazine, "Cosmetic Safety More Complex Than at First Blush" Doc. #2481.

Hysteresis

This is a measure of the energy lost or absorbed by a foam when subjected to deflection. In another sense, hysteresis is a measure of the ability of a foam to dampen vibrations. It is quantified as the area under a stress-strain curve as a load is applied

IFD

Indentation Force Deflection. A measure of load bearing capacity and expressed in psi. To obtain the value, the circular perforated plate is pushed into the foam top surface, stopping at a given deflection and reading a force on the scale. The higher the force the firmer the foam. Test Method D3574-

ILD

Indentation Load Deflection. An indication of the load-bearing ability of a foam. The standard test is to depress a 50 in2 indenter plate into the foam and measure the number of pounds required to achieve a desired deflection. This is described in ASTM Test Method D3574 and is no longer used as a description of load bearing.

Impedance Tube

Used to measure sound absorption properties. Standard test for foams is C384.

Indentation Modulus

IM = (40%IFD-20%IFD)/20%IFD. The force required to produce an additional 1% indentation between the limits of 20% IFD and 40% IFD determined without the one minute test. The slope of this line represents the resistance of the cell struts to post buckling. The slope of the linear portion of the stress-strain curve is as the indentation modulus.

IHF

Initial hardness factor is the ratio of 25% IFD to the 5% IFD. This factor defines the surface feel. Supple or soft-surface foams will have a high value and boardy or stiff-surface foams will have a low value. Another term for initial hardness factor is comfort factor.

Insulative

Electrical property range of 1014 - 1020 ohms/square

Irregular Cells

A term describing foam having widely varying cell sizes and presenting a very irregular appearance. Sometimes caused by excessive air introduced to the mixing head.

Isocyanate

A reactive chemical grouping composed of a nitrogen atom bonded to a carbon atom bonded to an oxygen atom (-N=C=O); a chemical compound, usually organic, containing one or more isocyanate groups.

Isocyanate Index

A measure of the stoichiometric balance between the equivalents of isocyanate used to the total equivalents of water, polyols and other reactants. The relative amount of isocyanate used as compared with the theoretical requirement. An index of 100 means just enough isocyanate is provided to react with all the compounds containing active hydrogen atoms. Normally, a slight excess of isocyanate is used (e.g., index 105).

Isotropic

Having the same properties in all directions.

K Factor

The term used for thermal conductivity representing a measure of the heat transmission characteristics of a material. For flexible polyurethane foams 0.25(BTU -in) / (hr - ft• - °F). SI units are W / (m - K). To convert from (BTU - in) / (hr - ft• - °F) to W / (m -K), multiply by 0.1442279. See also R Factor

Knit Lines

Lines describing where at least two advancing foam fronts have met during lay down of foaming mix. Knit lines can sometimes be associated with air trapping and/or shear collapse.

LMU

Low Molecular Weight Urethane. See Soxhlet Extraction

Lamination

A fabrication process bonding two foam types, or a foam and another substrate, using an adhesive.

Load Bearing

A general term, described in various ways by IFD, ILD, CFD, etc.

MDI

In the United States, usually the abbreviation for pure diphenylmethane diisocyanate. In other countries, it can be the undistilled mixture of diphenylmethane diisocyanate and higher molecular weight fractions.

Medical Foam

FXI does not manufacture any "medical foams" but rather manufactures foams that have been tested and approved by the user for use in medical applications.

Melting Point

Polyurethane foam will decompose before melting.

Metamerism

The tendency of foam color to shift hues when viewed under different light sources.

Micron

A dimension that is one millionth of a meter. To convert meters to inches, multiply meters X 39.37. Therefore: 20 microns/ 1 million X 39.37 = 0.000787 which is less than 1 thousandth of an inch.

Mixing Head

The device that mixes the component streams before dispensing the foam-producing mixture to the conveyor or container.

Mixing Lines

Visible lines of poorly formed foam. In a cut section of foam, these lines often radiate up from the pour spot to the top skin of the foam.

Modulus

Support Factor = 65%IFD/25%IFD determined after one minute or recovery. When based on 25% IFD values, the support factor indicates the 65% values that will be attained by the foam. Seating foams with low support factor are likely to bottom out under load.

Mold

Any enclosure in which a polyurethane mixture reacts to give a shaped final article.

Molecular Weight

Because individual polyol molecules vary in molecular weight, the molecular weight of a given polyol is a weighted average.

Monomer

A molecule or compound usually containing carbon and of relatively low molecular weight and simple structure.

Morphology

The physical form or structure in a polymeric material at the microscopic or sub-microscopic level, but not at the molecular level.

Montreal Protocol

See CFC.

Noise Reduction (NR)

The difference in sound pressure level between any two points along the path of sound propagation.

Noise Reduction Coefficient (NRC)

A mathematical average rounded to the nearest 0.05 of sound absorption coefficients (IR) recorded at the frequencies of 250, 500, 1000, and 2000Hz.

Non-Conforming Units

Attributes or units of data that do not meet specification.

Normal Incidence Sound Absorption (IN)

Sound absorption value of a material that has the sound entering perpendicular to its surface. Value found when using impedance tube or standing wave apparatus.

Normalized

Recalculated value of a measured property so it can be compared to other values that may have been measured on a different basis. For example, the practice of recalculating load-bearing for a foam just slightly off of target load-bearing density. See GUIDE FACTOR

Nucleation

The generation of many small bubbles within a liquid.

NVR

Non-Volatile Residue. Material remaining from a foam extract. Typically composed of low molecular weight urethanes, phthalates and anti- oxidants. See LMU and Soxhlet Extractor

Octave Band

Frequency range in with the upper limit of each band is twice the lower limit. They are identified by their geometric mean frequency.

One-Third Octave Band

Frequency ranges where each octave is divided into one-third octaves with the upper frequency limit being 2 1/3 (1.26) times the lower frequency. Identified by the geometric mean frequency of each band.

Open Cell

The ability of foam to allow air to pass through.

Open Cell Structure

A permeable structure (as in flexible foam) in which there are minimum barriers between cells, and gases or liquids can pass through the foam. Most cell walls have been ruptured.

Open Pore

Foam that may or may not have windows or membranes interconnecting the strands where air can pass through the foam.

Open Pour

The case where the dispensed foaming mixture is placed in an open-top mold or other containment structure.

Out of Control

Term used in SPC when a process shows non-random variation, usually with an assignable cause.

Pareto Chart

A bar graph showing the frequency of occurrence of various concerns, ordered with the most frequent one first. Used to decide which parts of a problem to work on first.

Particulate

Composed of fine particles.

Permeability

The rate at which a liquid or gas can penetrate into or through a flexible polyurethane foam. Usually associated with airflow, a measure of the openness of the foam that is expressed in cubic feet per minute. The sample size must be at least 4" x 4" to fit over the opening of the Frazier permeability device. The thickness varies with the product. In general, Maxfoam products are tested at 0.5 inch and CTM, LFM at one inch. Tech Products measures permeability parallel to the foam rise. See Frazier Air Permeability.

pH

A means of expressing the degree of acidity or basicity of a solution. The pH scale ranges from 1 to 14. A neutral solution has a pH of 7. Below 7, the solution is acidic. Above 7, the solution is basic.

PHR

Parts (by weight) per hundred parts of resin.

Polyester

A polymeric polyol material containing a number of chemical groups known as ester groups in the main chain or side chains.

Polyether

Polymeric polyol material containing a number of carbon- oxygen-carbon links, or linkages, in its main chain or side chain. Polyether foams tend to be more hydrolytically stable than polyester foams.

Polyisocyanate

A substance containing a number of isocyanate groups attached to a single molecule.

Polyisocyanurate

Polymers containing isocyanurate groups; i.e., cyclic trimers of isocyanates.

Polymer

An organic substance composed of repeating chemical units built up into large molecules.

Polyol

Generally, any organic molecule containing numerous hydroxyl groups; polyol is one of the key components of polyurethane foams, and can be either polyether or polyester type.

Polyurethanes

Generally, a polymer connected by urethane (or carbamate) groups. In polyurethane foams, these may be supplemented by ureas, isocyanurates, ester groups, biurets, allophanates, and others. In flexible foams, the most frequently occurring functional group is the urethane linkage.

Polyurethane Foam

A cellular product produced from the exothermic reaction of several compounds, including polyol, isocyanate, water, catalysts and additives.

Pore Size

One of the basic physical properties of a technical foam. The unit of measure is pores per inch (ppi), and can be determined several ways, including visually and by pressure drop. Pore size is used to describe one side, or face, of a cell. FXI pore size can be measured by 3 methods: pressure drop, visual comparison, or using the RAM Optical Comparator.

Porosity

The presence of numerous small cavities within a material. See Air Flow.

Post Cure

Time and temperature history of a molded article after removal from a mold.

Pour Pattern

The geometric manner in which the dispensed foaming mixture is laid down or placed into an open-top mold. In the simplest case, the mixture is poured at one spot and allowed to flow out to fill the mold. Complicated molds often require the mixing head (and perhaps the mold) to be moved in some manner so as to spread the mixture over a wider area of the mold.

PPHP

Parts (by weight) per hundred parts of polyol.

PPI

Pores Per Inch. See Pore Size.

Pressure Drop

A measure of how much resistance to flow a filter can have without affecting the amount of air needed, usually measured in inches of water. It also means that a certain height of water is needed for a given area to push air required through the filter. Other units are also used and they can be converted to inches of water as follows: Inches of mercury X 13.62 = inches of water PASCAL's (Pa) X 0.4021/100 = inches of water. At a constant air flow, the restriction to that air flow caused by the foam. The pressure drop value relates to pore size. Fine pore causes more restriction vs. Coarse pore; higher density foams cause greater resistance than lower density foams (at the same density). Most appropriate test for filtration applications. Most objective test method.

PrePolymer

A reacted, but not completely polymerized product. In the polyurethane industry, this is usually a pre-reacted product formed by reading polyol(s) with isocyanates(s). The materials normally contain residual free isocyanate groups for further reaction with more polyol(s) to produce the final polymer.

Process

The combination of people, equipment, materials, methods and environment that produce a given product or service.

Processability

The overall ease with which a product can be acceptably produced in a commercial facility given the normal day-to-day variations in equipment and people performance.

Processing Latitude

A condition said to exist in foam formulations, or with components, when the normal variations in processing parameters have no adverse effect on foam quality.

Properties of Foam

Examples of properties in specialty polyurethane foams which can varied depending on use are: surface area, cell structure, void volume, compression set, pressure drop, feel, color, resistivity, fire retardance, and chemical resistance.

Pyrolysis

The decomposition of polymers into liquids and gases by the application of heat.

QUV

An accelerated test used to help predict the effect of UV light on a material. The QUV simulates the effect of sunlight with fluorescent ultraviolet lamps. The unit in the FXI Technology Division uses UVA lamps to simulate outdoor UV exposure.

Quenching

One of the two major reticulation processes. A loaf of foam is immersed in a caustic solution, which removes the cell membranes leaving the strands. The foam is then rinsed and dried. Only polyester foams are reticulated by this method.

R&R Study

In SPC, Repeatability and Reproducibility. Repeatability is how close the measurements of an instrument are to each other if such measurements are repeated on a part under the same conditions. Reproducibility is a measure of the degree of agreement between two single test results made on the same object in two different, randomly selected measuring devices.

R Factor

Thickness in inches divided by k Factor in (BTU - in) / (hr - ft• - °F); used to determine effect of thickness on the ability of a material to provide insulation. See K Factor

RAM Optical

Measurement of cell diameter with a mathematical correlation to visual pore size. Applicable to functional & aesthetic applications. Less subjective than visual method, not as objective as pressure drop.

Range R

The difference between the highest and the lowest values in a subgroup.

Random Incidence Sound Absorption (IR)

Sound absorption Values of a material that has the sound entering the material at random angles. Values found when measuring sound absorption in reverberation room.

Range Chart

Usually used with Control Charts; shows point-to-point variation.

Ratio

Relative quantities of isocyanate stream to polyol stream on a weight basis.

Reactivity

A term broadly used to describe the results of empirical/analytical measurements to characterize the rates at which various polyurethane reactions occur.

Rebonded Foam

That foam resulting from a process of adhering small particles of foam back together again to make a usable cushioning product. Various adhesives and bonding processes are used. A typical application for rebonded foam is as carpet underlay.

Recovery Ratio

The ratio of 25% IFD released to 25% IFD initial when measuring IFD values at 25% deflection, 65% deflection, and then released back to 25% deflection. Recovery ratio is expressed as a percentage.

Relaxation (Sighing)

When foam rises to a maximum height and then settles back. All flexible urethanes do this to some extent. Excess sighing can be a sign of poor surfactant activity, incompatible mixing or a too-slow rate of polymerization.

Resilience or resiliency

A measure of foam elasticity of springiness. In this test, a steel ball is dropped on the foam and the rebound is expressed as percent resilience. As with recovery, desirable values are dependent on application. With very soft foam, resilience can be misleading because the foam bottoms out under the load of the ball. This gives low resilience values even though the foam is very "lively" or elastic. Ball rebound is another term for this property.

Reticulated Foam

Flexible polyurethane foams characterized by a three-dimensional skeletal structure with few or no membranes between strands. Reticulated foams are generally used as filters, acoustical panels, and for controlled liquid delivery.

Reticulation

The process, either thermal or chemical, that removes cell membranes from a cured foam. See Zapping Foam. See Quenching.

Reverberation Room

A room with long reverberation time. The walls of the room are highly reflective and care is taken to make sure the sound field is as diffused as possible.

Rise Time

The time between discharge of the foam ingredients from the mixing head and the point at which the foam rise is complete.

Root Cause Analysis

A systematic process for improvement and problem solving involving: identifying, defining in measurable terms, containment, collecting and analyzing relevant data and system of causes and determining root cause.

Run

Consecutive points on a control chart above or below the central line.

Run Chart

A chart of the measurement of a characteristic over time. Used to denote the presence of trends or shifts in the process. Not as effective as control charts in indicating a problem.

SPC

A tool for predicting and regulating variation and process outputs. SEE Statistical Process Control.

Sag Factor

Sag factor is the ratio of 65% IFD to 25% IFD and gives an indication of cushioning quality. A high value indicates resistance to bottoming out. Foams with low sag factors will often "bottom out" and give inferior performance.

Sample

Per SPC: one or more individual measurements or events selected from a process.

Scorch

A yellow or brown discoloration of the foam, particularly in the center. Scorching is caused by excessive heat during the exothermic reaction. It occurs mainly in high water, flexible slabstock formulations.

Seam

The splice line formed by two or more separate pieces of flexible polyurethane foam that have been bonded together.

Semiflexible Molded

Foams that are used primarily by the automotive industry in safety, padding and interior trim applications. The ability to shape semi-flexible foam by closed molding in a cover stock gives automotive stylists and engineers exceptional design freedom and a highly functional end product.

Semirigid Molded Foams

Foams that are friable in nature and do not fully recover after deformation. Both energy management and matt molded foams are included in this classification

Settling

The observable and normal loss in height of a free-rise foam at a point in time just after the peak rise. Height loss occurs when the cell walls rupture and the expansion gas is lost. If a loss in height is not observed, the foam will normally be closed-cell.

Shear Collapse

Localized loss of molded-foam polymer integrity resulting in a void containing a coarse, stringy polymer mass.

Shelf Life

The time a material can be stored without losing any of its properties.

Shiners

Light reflected from intact cell walls, noticeable on the cut surfaces of flexible polyurethane foam. A large number of shiners, or shiny spots, indicates a foam with closed cells.

Shot (of foam)

The total amount of mixed liquids dispensed during one pour cycle.

Shrinkage

The contraction of curing foam due to the cooling of entrapped gases within the closed-cell walls of a foam mass.

SIF Felt or Scotfelt

Trademark name for a foam that has been compressed under heat and pressure to a specified thickness. Felted foams are defined by firmness or the reciprocal of the compression ratio expressed in a whole number. Example: to produce a 5-900 1/2 inch felt, 2 1/2 inches of 90 ppi foam was compressed under heat and pressure until a stable product, 1/2" thick, resulted. Foam can be compressed to any number of thicknesses, including increments of the whole, depending only on the limitations of the process. The density of a felted product is increased proportionately by the firmness number, i.e., if the density of the base foam (before felting) was 1.90 lbs/ ft3, the final density would be approximately 9.5 lbs/ ft3. In other words, felting decreases the volume that the same weight formerly occupied. Both polyester and polyether foams reticulated and non-reticulated can be felted.

Sigh Back

See Relaxation.

Six Sigma

Quality philosophy which supports a collection of techniques and tools for use in reducing variation; also a program of improvement which focuses on strong leadership tools and an emphasis on bottom-line financial results.

Silicones

Chemicals formed from a combination of silicon and organic molecules that exhibit surface-active properties. These compounds are used to add stability to the liquid foaming mixture so that drainage is retarded and flowability of the mass is improved. See Surfactants.

Skin

The higher-density outer surface of a foam block.

Slab

A section of foam cut from the interior of a large bun.

Slabstock

Refers to polyurethane foam made in the form of a long, continuous block or bun of nominal rectangular cross- section.

Smoke Suppressant

Particulate inorganic and/or organic materials used to reduce the amount of smoke or to slow down the rate of smoke production in burning.

SMT

Surface Modification Technology. A proprietary and patented process allowing for various features of a foam to be altered, including the pattern, the size of the pattern, the depth of the cut, the spacing between patterns, the location of each distinct patter and the remaining level of foam. Often used for discreet parts.

Soft Segments

That portion of a polyurethane polymer comprised of the higher molecular-weight polyol chains present as a bulk continuous phase. This phase has a glass transition temperature well below ambient temperature and thus exhibits good flexibility at ambient temperatures.

Softness

A subjective characterization usually determined by squeezing a foam with the fingers of hands. Soft foams generally have open cells, high airflow and small cell size.

Sound

A vibrational disturbance transmitted through a medium that excites our hearing mechanism.

Sound Absorption Coefficient

A dimensionless ratio of sound energy absorbed by a given surface to that incident upon the surface. Expressed in percent.

Sound Level Meter

Instrument used to measure sound pressure level (dB). Usually has three weighting scales A, B, and C. May also have one-third octave analyzer.

Sound Transmission Class (STC)

A single number decibel rating of the transmission loss properties of a partition. Measured transmission loss data is plotted versus frequency and compared with standard contours.

Sound Transmission Loss (TL)

A logarithmicration of the sound power incident on one side of a partition to the sound power transmitted on the other side.

Soxhlet Extraction

The name for a specific type of glassware used in extractions. The material to be extracted is placed in the Soxhlet extractor. The extractor is placed onto a round bottom flask containing the extraction solvent. A condenser is placed on top of the extractor. The solvent is heated to its boiling temperature. The gaseous solvent condenses and fills up the extractor. When the extractor reaches full capacity, the solvent refluxes back into the round bottom, carrying the extractable with it. This extraction technique allows for a sample to be continuously extracted with distilled solvent at a temperature very close to boiling.

Special Cause

In SPC, a source of variation that is intermittent or unpredictable signaled by an out-of-control condition on a control chart.

Specialty Industrial Foam

SIF. FXI's class of reticulated polyester polyurethane foams.

Specification

An engineering requirement for judging the acceptability of a particular characteristic. NOT related to a control limit.

Stability

Per SPC: the absence of special causes of variation where only common causes remain.

Standard Deviation

A unit of measure to denote the spread of the process output or a sampling statistic from the process.

Static Fatigue

The loss in load-bearing properties of a foam subjected to a constant compression.

Statistical Process Control (SPC)

The use of statistical techniques (such as control charts) to analyze a process, take appropriate action to gain and maintain statistical control and improve process capability.

Statistically Insignificant

Using hypothesis tests, there is no mathematically detectable difference.

Struts / Strands

The structural members of a foamed material. These rounded triangular features contain most of the solid polymer and are at the nexus of the strands.

Subgroup

One or more events or measurements used to analyze the performance of a process.

Substrate Process

In semi-flexible foams, the process of manufacturing plastic or metal substrates which are the main energy-absorbing and structural components in an instrument panel or other interior trim part.

Summer Softness

A condition in which the load-bearing capacity of standard foams produced during the summer months decreases in direct proportion to the amount of airborne moisture available.

Support Factor

The ratio of the 65% IFD to the 25% IFD. Seating foams with low support factors may bottom out and be less comfortable. See Sag Factor.

Surfactants

A term to describe substances that provide resiliency and stability to thin films and that markedly lower the surface tension of liquids, thus permitting easier bubble formation.

System

In polyurethane or polyisocyanurate technology, the two or more substances or materials which, when mixed together, react to form a polyurethane or polyisocyanurate polymer.

TDI

Toluene diisocyanate. A highly reactive and key component of polyurethane foams.

TDI Index

This figure indicates the amount of TDI (toluene diisocyanate) available for reaction with the polyol, water, and other active-hydrogen sources. An index of 105 indicates that there is 5% excess TDI available over the stoichiometric amount required by the formulation.

Tear Strength

A measure of the force required to continue a tear in a foam after a split or break has been started and expressed in pounds per inch (lbs./in.). This property is important in determining suitability of foam in applications where the material is sewed or stapled. ASTM D-3574-01 Test F.

Temperature Range Flexible Polyurethane

Most Polyurethane Foams are good from -40°F to 200°F under constant usage. 201°F to 250°F under intermittent usage.

Tensile Strength

The tensile properties are important characteristics of the strength of any material. The specimen is stretched at a constant standard rate until it breaks. The tensile strength is the maximum stress the material withstands before rupture. ASTM D-3574-01 Test E.

Thermal Reticulation

See Zapping

Thermoplastic

A material capable of melting at elevated temperatures without degradation and regaining its original properties after further processing and re-cooling.

Thermoset

A material that is cured by temperature and decomposes rather than melts upon application of elevated temperatures. Polyurethane foams fall into this category.

Throughput

The total flow rate of all components leaving the mixing head.

Tight Foam

Flexible polyurethane foam with many closed cells, resulting in low flow measurements.

Trimming

A process used to remove the flash from a molded foam pad.

U-Channel

A test used to determine water impermeability of a flexible foam gasket.

UL

Underwriters Laboratories. An independent, non-profit organization testing for public safety. UL is chartered to establish, maintain, and operate laboratories for the examination and testing of devices, systems, and materials to determine their relative hazards to life and property.

UL 94

Underwriters Laboratories horizontal burn test applying to flexible polyurethane foam with ratings of HF1, HF2 and HBF.

UL 900

Underwriters Laboratories burn test relating to smoke generation and used in the HVAC market.

Universal Filter Tester

Filtration equipment similar to the AFI unit, but in a vertical direction to allow for low air velocity testing. It has the capability of determining pressure drop, efficiency and dust holding capacity. Built and designed by FXI

Unsaturation

There may be small amounts of allyl-or propenyl-type unsaturation in polyols, resulting from propylene oxide isomerization during polyol manufacture. This unsaturation is usually associated with a monohydroxy, hence a chain terminator. Unsaturation is expressed as the number of milliequivalents per gram (meq/g) of polyol sample.

Urethane

Generally, the reaction product of an isocyanate and an organic hydroxyl.

VPF

Variable Pressure Foaming. A method of making flexible polyurethane foam where the foam machine in enclosed in a pressure vessel or chamber for the purpose of controlling foam properties. By controlling atmospheric pressure, for example, densityand ILD can be independent. This type of equipment does not require CFC's to achieve very soft foams and does not emit VOC's into the atmosphere.

Vapor Pressure

The pressure of a vapor above the liquid from which it formed. Vapor pressure is temperature dependent.

Variables

Quantitative data where measurements are used for analysis.

Variation

The difference among individual outputs of a process. Special causes and common causes.

Virgin Foam

Flexible slabstock foam that has not been processed in any manner other than cutting to shape.

Viscosity

Viscosity is influenced by the molecular weight and molecular structure of the polyol, and is therefore an important physical property. Viscosities of polyols are expressed in centistokes or centipoises. The two are related by the following equation: Centistoke X Density = Centipoise where density is expressed in g/cm•.

Visual with Standards

Comparison of a sample to accepted standards. Customer and FXI must agree to standards most appropriate for applications where appearance is more important than function. Very subjective method.

Void Volume

Percent of matrix not occupied by foam strands. Void Volume = (100 - % solid volume). % Void Volume can be calculated as follows: 100 -(Foam density/polymer density) x 100. At a given density, pore size and void volume are independent. Polyester polymer density pcf = 74.7, Polyether polymer density = 67.4pcf.

Water Content

Water can exist in a free, non-chemically bound state in a polyol. Manufacturers normally report the water content of each lot of polyol in units of weight percent. The water content should be taken into account when doing foam-making calculations.

Water Blown Foam

Foam in which the gas for expansion is generated entirely by the reaction of water with an isocyanate.

Wave Length

The physical distance between identical points on successive waves. Wavelength is a function of frequency (f) and the speed of sound (c).

Weldability

The inverse of clickability. Some foam applications call for foam to weld or seal. FXI's policy on clickability/weldability: FXI will certify to the click rating evaluated in the laboratory at ambient temperature & humidity with an ASTM D 3574 tensile die on a 1" thick piece of foam. FXI cannot guarantee clickability under every condition listed above. However, FXI will provide technical support to help solve customer die-cutting issues.

Wetting

The tendency of a liquid to spread over a surface. A decrease in the contact angle between the solution and the surface is shown by an increase in wetting. A zero contact angle corresponds to spontaneous spreading. The ease with which a surface can be wetted by water or by other liquids is an important property from many considerations, including detergency, waterproofing, oil proofing, dyeing, dispersion of pigments, and water absorption. Wetting agents are classified practically according to their ability and speed in displacing air from solid surfaces. A surfactant can act as a wetting agent.

Wicking

Transporting fluid from a reservoir to an application surface.

Windows

The thin membranes formed between adjacent gas bubbles as those bubbles expand enough to pack into various polyhedral shapes. These features may be present (a closed-cell window) or absent (an open-cell window) depending on the particular foam chemistry used.

Zapping

One of the two major reticulation processes. Foam buns are placed in a chamber and an explosive mixture of gasses is introduced to the foam and ignited which removes the cell membranes. Also called thermal reticulation.