Patent GB-514821-A (GB)
Title: Improvements in and relating to textiles
IPC: D02G1/00
Filed: 1938-02-15
Abstract: 514.821. Crimping artificial fibres, threads &c. DU PONT DE NEMOURS & CO., E. I. Feb. 15, 1938, Nos. 4668, 4669, 4670. [Convention dates, Feb. 15, 1937], and 4671, [Convention date, Jan. 7, 1938]. [Class 120 (iii)] [Also in Group IV] Wool substitutes consist of or comprise one or more intrinsically crimped or curled filaments or fibres composed wholly or in part of one or more synthetic linear superpolymers obtainable by condensation, especially superpolyamides, e.g., polyhexamethylene adipamide. Other superpolymers referred to are polyesters, polyethers, polyanhydrides, and polyacetals. The polymer may be extruded from the molten state and the filaments may be cold drawn, e.g., while wet with a mild swelling agent. Crimping may be effected spontaneously by drying the cold-drawn filaments in relaxed condition, or it may be effected by crimping rollers or other means independent of customary knitting or weaving operations. The crimp may be set by treatment with hot water, steam, alcohol or other liquid or by dry heat. Polyamides of intrinsic viscosity 0.5-2.0 as measured in a mcresol solution may be used. The filaments may be subjected to a short heat treatment in air, steam, mineral oil" esters, ethers, mercury, or molten Wood's metal, preferably while wet with a mild swelling agent, and before or after or between cold-drawing operations, and may then be crimped by drying in relaxed condition. A plurality of undrawn or partly drawn filaments may be twisted together to form a thread, cold drawn, further twisted in the same direction, treated with a setting agent, e.g., steam, and then twisted in the opposite direction. Sufficient crimp may be introduced to give a ratio of straight to crimped length in relaxed position of at least 2. In an example, yarns of a polyamide are heated in oil, washed, colddrawn while wet. washed with acetone, and carried by an air-jet to the top of a column up which passes an air-current just insufficient to support the yarn. The yarn dries and crimps in the column. On reaching the bottom the yarn is laid on a belt which carries it through saturated steam.. In another example, the crimped yarn is woven into' a fabric in which it forms the weft, spun rayon being used as warp. The fibres may be crimped by pressing them between intermeshing gears and subjecting them to heating. Yarns or fibres may be crimped by winding them on a mandrel or around a wire and heating them, preferably in presence of steam. In another example, mixed polyamide filaments are formed into a thread and then into a larger thread by twisting with other similar threads. The thread is colddrawn to such an extent that some of the filaments break, e.g., by drawing it between two closely spaced bobbins having different peripheral soeeds. In another example, the filaments are cold-drawn while still containing residual solvent. i.e., formic acid. and then wound round a small wire and heated in boiling water. The crimped fibres may be formed into wool-like yarns by feeding two strands into a twister at different rates. The yarns may be knitted or woven into fabrics or rugs. The fibres may be used as down substitutes for stuffing pillows, or upholstery. They may be associated with' other fibres of all kinds. Specifications 461,236, 461.237, and 495,790, [all in Group IV], are referred to.