IMMEDIATE ELASTIC DEFORMATION: Recoverable deformation that is essentially independent of time, i.e., occurring in (a time approaching) zero time and recoverable in (a time approaching) zero time after removal of the applied load.
IMPACT RESISTANCE: 1. The resistance of a material to fracture by a blow, expressed in terms of the amount of energy absorbed before fracture. 2. In yarn or cord, the ability to withstand instantaneous or rapid rate of loading.
IMPACT STRENGTH: See IMPACT RESISTANCE.
IMPREGNATED FABRIC: A fabric in which the interstices between the yarns are completely filled, as compared to sized or coated material where the interstices are not completely filled. Not included in the definition is a woven fabric constructed from impregnated yarns, rather than one impregnated after weaving.
INDEX OF REFRACTION: Ratio of the velocity of light in one medium to its velocity in a second medium as the light passes from medium to medium. If a medium is crystalline, the velocity may depend on the direction of the light with respect to the crystalline axes and the substance may have several indexes of refraction, i.e., it may be birefringent. (Also see BIREFRINGENCE.)
INDIGO: Originally, a natural blue vat dye extracted from plants, especially the Indigofera tinctoria plant. Most indigo dyes today are synthetic. They are frequently used on dungarees and denims.
INDUSTRIAL FABRIC: A broad term for fabrics used for nonapparel and nondecorative uses. They fall into several classes: (1) a broad group including fabrics employed in industrial processes (e.g., filtering, polishing, and absorption), (2) fabrics combined with other materials to produce a different type of product (e.g., rubberized fabric for hose, belting, and tires; fabric combined with synthetic resins to be used for timing gears and electrical machinery parts; coated or enameled fabrics for automobile tops and book bindings; and fabrics impregnated with adhesive and dielectric compounds for application in the electrical industry), and (3) fabrics incorporated directly in a finished product (e.g., sails, tarpaulins, tents, awnings, and specialty belts for agricultural machinery, airplanes, and conveyors). Fabrics developed for industrial uses ncover a wide variety of widths, weights, and constructions and are attained, in many cases, only after painstaking research and experiment. Cotton and manufactured fibers are important fibers in this group, but virtually all textile fibers have industrial uses. The names mechanical fabrics or technical fabrics sometimes have been applied to certain industrial fabrics.
INFLATABLE STUCTURES: Structures opened or enlarged by input of air and, once enlarged, able to retain the air to maintain the distended position.
INGRAIN: See DYEING.
INHERENT VISCOSITY: See INTRINSIC VISCOSITY.
INHERENT FLAME RESISTANCE: As applied to textiles, flame resistance that derives from an essential characteristic of the fiber from which the textile is made.
INHIBITOR: A substance that retards or prevents a chemical or physical change. In textiles, a chemical agent that is added to prevent fading, degradation, or other undesirable effects.
INITIAL MODULUS: The slope of the initial straight portion of the stressstrain curve. The modulus is the ratio of the change in stress, expressed in newtons per tex, grams-force per tex, or grams-force per denier, to the change in strain expressed as a fraction of the original length.
INITIATOR: A chemical added to start a reaction such as polymerization. Unlike catalysts, initiators may be consumed during the reaction.
INSPECTION: The process of examining textiles for defects at any stage of manufacturing and finishing.
INSTRON TENSILE TESTER: A high precision electronic test instrument designed for testing a variety of material under a broad range of test conditions. It is used to measure and chart the load-elongation properties of fibers, yarns, fabrics, webbings, plastics, films, rubber, leather, npaper, etc. May also be used to measure such properties as tear resistance and resistance to compression.
INTAGLIO: 1. Printing style in which the design is cut into the surface of the cylinder and is thus below the surface. 2. A lustrous, brocade pattern knitted in a tricot fabric.
- The amount of energy per unit (space, charge, time).
- The brilliance of a color.
- The brightness of light.
INTERFACING: See INTERLINING.
INTERLINING: A padding or stiffening fabric used in garment manufacture to provide shape retention. Interlining is sandwiched between layers of fabric.
- Use of air jets to create turbulence to entangle the filaments of continuous filaments yarns, without forming loops, after extrusion. Provides dimensional stability and cohesion for further processing but is not of itself a texturing process. It is compatible with high-speed spin-drawing and high-speed take-up. When compared with twisting processes, it also permits increased take-up package size.
- Combining two or more yarns via an intermingling jet. Can be used to get special effect yarns, i.e., mixing dye variants to get heather effects upon subsequent dyeing.
INTERNAL DYE VARIABILITY: The change from point to point in dye uniformity across the diameter and along the length of the individual filaments. Affects appearance of the dyed product and is a function of fiber, dye, dyeing process, and dyebath characteristics.
INTERNATIONAL GRAY SCALE: A scale distributed through AATCC that is used as a comparison standard to rate degrees of fading from 5 (negligible or no change) to 1 (severe change). The term is sometimes applied to any scale of quality in which 5 is excellent and 1 is poor.
INTIMATE BLEND: A technique of mixing two or more dissimiliar fibers in a very uniform mixture. Usually the stock is mixed before or at the picker.
INTRINSIC VISCOSITY: Ratio of the specific viscosity (R.V.-1) of a solution of known concentration to the concentration of solute extrapolated to zero concentration. Also called the limiting viscosity number. It is directly proportional to the polymer-average molecular weight.
IONOMER: A polymer having covalent bonds between the constituents of the long-chain molecules and ionic bonds between the chains.
ISLANDS-IN-THE-SEA: A type of component fiber described as multipleinterface or filament-in-matrix. The “island” are fibrils of one or more polymers imbedded in the “sea” (or matrix) consisting of another polymer. The matrix is often dissolved away to leave filaments of very low denier per filament. These fibers have been used in ion-exchange products and in imitation fur products as well as to mproduce textile products with a different hand.
ISOTACTIC POLYMER: A polymer structure in which there is a regular spatial or stereo relationship from one repeat unit to the next. (Also see ATACTIC POLYMER, SYNDIOTACTIC POLYMER, and TACTIC POLYMER.)
ISOTROPIC: Having the same physical properties in every direction in the plane of a fabric. It is related to the random distribution of fibers in nonwoven manufacture.