Industry Glossary - T

Surface stickiness.

Surface, which is not sticky after cure.

Slope of the line at a predefined point on a static stress-strain curve, expressed in force per unit area per unit strain. This is the tangent modulus at that point in shear, tension, or compression, as the case may be.

A narrow fabric with a mass per unit area of less than 0.5 kg/m 2 (0.1 LB/ft2) for each 25.4 mm (1 in.) of width and which is used primarily for utilitarian purposes.

Engineering term referring to the amount of stretch a sample experiences during tensile strain.

Load applied away from and to opposite ends of a given sample.

When a bar is pulled in tension, it has to get longer. The tensile modulus is used to calculate how much longer it will get when a certain load is applied to it. Units are normally millions of pounds per square inch. (10 6 psi) – Giga Pascals (gPa). Higher numbers indicate materials which will not elongate as much as others when they are being compared under equal tensile loading conditions.

This number describes how large a nonmoving load a bar can withstand before it breaks due to elongation. Units are normally thousands of pounds per square inch. (103 psi) – Mega Pascals (mPa). Higher numbers indicate materials which can withstand a stronger pull before breaking.

Normal stress caused by forces directed away from the plane on which they act.

A mechanical or magnetic device that controls tension.

A unit for expressing linear density, equal to the mass in grams of 1 km of yarn, filament, fiber or other textile strand.

A yarn processed from continuous filament yarn in such a manner to induce bulk to the yarn by disorientation of the filaments.

The maximum number of bundles that are in a roving doff, e.g., a roving doff made with 18 forming cakes in the creel that were “split out” 4 ways in forming will have 64 theoretical ends.

This is a measurement of how much the length of a material will change when the material is heated or cooled. The value given is based on the inch as a unit. The number given shows how much this inch of material will increase if the temperature of the material is raised one degree Fahrenheit. Units – inches per inch per degree Fahrenheit (in/in/�F) – Meters/Meter/�C. Higher numbers mean that the material will expand or lengthen more for each degree rise in temperature. Smaller numbers indicate relative stability to changes in temperature.

This property is known as the K factor. It is a measure of the transfer of heat by conduction. It tells how much heat is transferred from one side of a plate to the other side. It is measured as BTUs (units of heat in the English system) per hour per unit area (square feet) for a thickness of one inch and a temperature difference of one degree Fahrenheit between both sides of the plate. Units – BTU/hr/sq/�F/inch. – Watt/(Meter Deg Kelven) W/MK. Higher numbers mean that the material will absorb more energy before it is broken by a moving weight.

Capable of being repeatedly softened by an increase of temperature and hardened by a decrease in temperature. Applicable to those materials whose change upon heating is substantially physical rather than chemical and that in the softened stage can be shaped by flow into articles by molding or extrusion.

Class of thermoplastic polymers in which the repeating units are joined by ester groups. The two important types are (1) polyethylene terephthalate (PET), which is widely used as film, fiber, and soda bottles; and (2) polybutylene terephthalate (PBT), primarily a molding compound.

A material that will undergo a chemical reaction caused by heat, catalyst, etc., leading to the formation of a solid. Once it becomes a solid, it cannot be reformed.

Class of resins produced by dissolving unsaturated, generally linear, alkyd resins in a vinyl-type active monomer such as styrene, methyl styrene, or diallyl phthalate. Cure is effected through vinyl polymerization using peroside catalysts and promoters or heat to accelerate the reaction. The two important commercial types are (1) liquid resins that are cross-linked with styrene and used either as impregnants for glass or carbon fiber reinforcements in laminates, filament-wound structures, and other built-up constructions, or as binders for chopped-fiber reinforcements in molding compounds, such as sheet molding compound (SMC), bulk molding compound (BMC), and thick molding compound (TMC); and (2) liquid or solid resins cross-linked with other esters in chopped-fiber and mineral-filled molding compounds, for example, alkyd and diallyl phthalate.

Material added to the resin to thicken it or raise the viscosity index of the resin so that it will not flow as readily.

The property of becoming a gel at rest, but liquifying again on agitation.

Gel coat formulated for mold surfaces.

The smooth and successful transition from one roving doff to another during processing.

Permits a percentage of light to pass but not optically clear like window glass.

A loop which was embedded into the roving doff during the roving process which gets stuck during run-out with sufficient tenacity that it prevents the entire strand from running freely to the chopper.

The failure of the glass to run through the metal tubes or guide-eyes from the creel to the chopper. This usually caused by a large knot or small birdnest becoming stuck inside the tube or guide-eye.

One 360� revolution of the components around the axis of the strand.

The portion of the roving doff where the roving changes direction when it is pulled out of the doff.

Machines used to twist and ply glass yarns.