Abrasion Resistance

The ability of a fiber or fabric to withstand surface wear and rubbing.

Crimp

1. The waviness of a fiber expressed as crimps per unit length. 2.The difference in distance between two points on an unstretched fiber and the same two points when the fiber is straightened under specified tension. Crimp is expressed as a percentage of the unstretched length. 3. The difference in distance between two points on a yarn as it lies in a fabric and the same two points when the yarn has been removed from the fabric and straightened under specific tensions, expressed as a percentage of the distance between the two points as the yarn lies in the fabric.

Denier

A weight-per-unit-length measure of any linear material. Officially, it is the number of unit weights of 0.05 grams per 450-meter length. This is numerically equal to weight in grams of 9,000 meters of the material. Denier is a direct numbering system in which the lower numbers represent the finer sizes and the higher numbers the coarser sizes. In the U.S., the denier system is used for numbering filament yarns (except glass), man-made fiber staple ( but not spun yarns), and tow. In most countries outside the U.S., the denier system has been replaced by the tex system. The following denier terms are in use: Denier per Filament (dpf): The denier of an individual continuous filament or an individual staple fiber if it were continuous. In filament yarns, it is the yarn denier divided by the number of filaments. Yarn Denier: The denier of a filament yarn. It is the product of the denier per filament and the number of filaments in the yarn. Total Denier: The denier of a tow before it is crimped. It is the product of the denier per filament and the number of filaments in the tow. The total denier after crimping ( called crimped total denier) is higher because of the resultant increase in weight per unit length.

Elastic Recovery

The degree that a fiber, yarn, or cord will return to its original size and shape after deformation from stress.

Elongation

The deformation in the direction of load caused by a tensile force. Elongation is measured in units of length (e.g., milimeters, inches) or calculated as a percentage of the original specimen length. Elongation may be measured at any specified load or at the breaking load.

Filament Yarn

A yarn composed of continuous filaments assembled with or without twist. ( Also see YARN)

Hydrolysis

A double decomposition reaction involving the addition of the elements of water and the formation of an acid and ?base, an acid and an alcohol, or an acid and phenol.

Hydroscopic

Having the ability to absorb moisture from the atmosphere. All fibers have this property in varying degrees.

Knitted Fabric

A structure produced by interlooping one or more ends of yarn or comparable material. ( Also see KNITTING.)

Linear Density

Mass per unit length expressed as grams per centimeter, pounds per foot, or equivalent units. It is the quotient obtained by dividing the mass of a fiber or yarn by its length.

Melting Point

The temperature at which the solid and liquid states of a substance are in equilibrium; generally, the temperature at which a substance changes from a solid to a liquid.

Modulus

The ratio of change in stress to change in strain following the removal of crimp from the material being tested; I.e., the ratio of the stress expressed in either force per unit linear density or force per unit area of the original specimen, and the strain expressed as either a fraction of the original length or percentage elongation. ( Also see YOUNG'S MODULUS)

Specific Gravity

Ratio of the mass of a material to the mass of an equal volume of water at 4 degrees Celcius. The range for modern fibers is not too great and is dependent to some extent on the liquid used as an immersant in measurement, because of fiber swelling and of possible absorption of liquid into fiber voids. ( Also see DENSITY)

Spun Yarn

1. A yarn consisting of staple fibers usually bound together by twist. 2. A melt-spun fiber before it is drawn.

Staple Fiber

Natural fibers or cut lengths from filaments. The staple length of natural fibers varies from less than 1 inch as with some cotton fibers to several feet for some hard fibers. Man-made staple fibers are cut to a definite length, from 8 inches down to about 1.5 inches (occasionally down to 1 inch), so that they can be processed on cotton, woolen, or worsted yarn spinnning systems. The term staple (fiber) is used in the textile industry to distinguish natural or cut length man-made fibers from filament.

Tensile Strength

Specifically, the maximum tensile stress expressed in force per unit cross-sectional area of the unstrained specimen, e.g., kilograms per square millimeter, pounds per sqaure inch.

Thermal Conductivity

A measure of heat flow through a material.

Woven

A fabric composed of two sets of yarns, warp and filling, and dormed by weaving, which is the interlacing of these sets of yarn to form a fabric. There may be two or more wraps and fillings in a fabric, depending on the complexity of the construction. The manner in which the two sets of yarn are interlaced determines the weave. By using various combinations of the three basic weave, plain, twill and satan, it is possible to produce an almost unlimited variety of constructions. Other effects may be obtained by varying the type of yarns, filament or spun, and the fiber types, twist levels, etc.

Yarn

A generic term for a continuous strand of textile fibers, filaments, or material in a form suitable for knitting, weaving, or otherwise intertwinging to form a textile fabric. Yarn occurs in the following forms: 1)a number of fibers twisted together ( spun yarn), 2) a number of filaments laid together without a twist ( a zero-twist yarn), 3) a number of filaments laid together with a degree of twist, 4) a single filament without twist ( monofilament) or 5) a narrow strip of material, such as paper, plastic film, or metal, with or without twist, intended for use by a textile construction.

Youngs Modulus

A property of perfectly elastic materials, it is ratio of change in stress to change in strain within the elastic limits of material. The ratio is calculated from the stress expressed in force unit cross-sectional area , and the strain expressed as a fraction of original length. Modulus so calculated is equivalent to the force required to strain the sample 100% of its original length, at the rate prevailing below the elastic limit.

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