Urethane and Polyurethane Industry Glossary

Fadeometer

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.

False RMA

A term which refers to the practice of increasing the initial RMA of a foam sample by formulation techniques which give only a temporary boost in firmness that is soon lost in normal use (flexing) of the foam product. See RMA, IFD,and flex fatigue.

Fast Heat

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 time, 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.

Filler

An inert material added to the foam formulation 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 fillers often result in higher load bearing properties but lower tensile and tear strengths.

Filter

A device to remove unwanted particles of material from the liquid streams of chemicals. For trouble free operation all lines should be properly filtered.

Fine Cells

A term which is used to describe foam with a cell count of 80 or more per lineal inch, See cell size.

Fingernail

A foam industry 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 between foams.

Fixed Calibration Time

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 Ratio

The condition of having all components with a fixed throughput so that ratio variations are not possible. See Ratio Control.

Fixed Throughput (Fixed Flow rate)

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 possible.

Fixtures

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.

Flak

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 reaction has been excessively retarded in relation to the blowing' reaction.

Flame Lamination

The practice of sticking together or gluing flexible foam 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 of foam (normally classed as a thermoset) is needed. See definition of thermoset and thermoplastic.

Flame Retardent

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.

Flammability

Describes the relative burnability of the material in a specified situation. Meanings vary according to the test method used.

Flaps

The external symptom of large internal blows or voids. These generally develop just past the peak rise point 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 slab 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.

Flex Fatigue

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 D 1564-63T.

Flexible Mold Material

The rubber like material used for molding very intricate shapes and contours into rigid foam. These materials can be any elastomers 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 before use.

Flexible Molds

Molds made of rubber or elastomeric plastics used for casting plastics. They can be stretched to remove cured pieces with undercuts.

Flexible Shaft Adapter

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.

Flexible 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 drive'.

Flexible Strength

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.

Floating Lid

A term used to describe a special lid used on some flexible foam 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 foam against the gradually increasing compression of springs. The use of this type lid appears to minimize the appearance of loose skin and hard spots in the cushions.

Flow

Rate of all chemicals.

Flow Lines

A term which refers to a pattern of high density streaks or ridges radiating upward from the bottom of a Block of flexible slab foam. They are usually caused by undercutting (channeling) of the foam front or pouring freshly mixed materials on top of rising foam. See bones.

Flowmeter

A flow indicating 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.

Flow-Rate

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 flow rates).

Fluorocarbon

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 agents.

Fluorocarbon Blown Foam

Foam produced entirely by the gas generated from the boiling of a fluorocarbon, such as trichlorofluoromethane (R-11).

Foam

In the sense the term is used in the urethane foam 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).

Foam Fatigue

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.

Foam-in-Place

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.

Foam Line

See cream line (Also refers to a foam producing assembly line)

Formula

The list of ingredients and their proportions to each other which must be used to make a particular foam product.

Formulation

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 is attained under free rise conditions.

Friable (Foam)

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 material into the final foam mixture (in a pressurized mixing chamber). When this liquid is discharged from the pressurized chamber, it expands instantly into a semi-liquid foam (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 liquid used for frothing.

Froth Mixing Head

A mixing device for urethane foam that is designed for introducing the low boiling point frothing agent into the mixing chamber as a liquid and is capable of withstanding internal pressurization up to approximately 250 psig. in the mixing chamber without leakage problems.

Froth Spray

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 density 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.

Full Recirculation

A term applied to a urethane foam machine designed to permit all fluid components 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 should be immediately adjacent to the chamber so that stagnant areas are eliminated. See short recycle valving.

Fully Automatic Solvent Flush

The solvent flush cycle is initiated automatically by the machine.

Functionality

The number of reactive groups attached to a single molecule. A polyol with a functionality of 2 would be a diol.

Furniture Foam

Rigid urethane foam of a quality, density and appearance suitable for replacing wood products. Most of the formulations would produce foam in the 25 to 30 pound per cubic foot density range (similar to white pine) although lower density foams are available.

URETHANE INDUSTRY GLOSSARY - F