GB884163A - Improvements in or relating to artificial filamentary structures - Google Patents

Abstract

Composite filamentary structures are produced by simultaneously spinning fibre-forming polymers of at least two types, of which p at least one is an elastomer and at least one other is a synthetic polymer capable of being extruded and drawn to yield filaments having an elongation substantially less than that of the filaments made from the elastomer or elastomers, the spinning being carried out under such conditions that the elastomeric filaments adhere to the non-elastomeric filaments to form composite filamentary structures, the adhesion in which can be broken in subsequent drawing operations to form a bulky yarn-like structure. The composite filamentary structures are drawn by an amount less than the breaking elongation of the components but beyond any irreversible extension of the elastomeric component or components, preferably at least twice the original length. They are then converted into a bulky yarn-like structure by relaxation so as to allow retraction. The elastic filaments are then still substantially straight and the non-elastic filaments randomly looped about them. In an example, a segmented condensation elastomer is prepared by condensing poly (tetramethylene oxide) glycol (1 mol.) having a molecular weight of 1,000 with 0,5 mol. of toluene diisocyanate. 1 Mol. of the resulting dimer is then reacted with 2 mols. of methylene bis(4-phenyl-isocyanate). The resulting polyether diurethane (1 mol.) is then reacted with 1 mol. of hydrazine monohydrate to produce a copolymer. A spinning solution in dimethyl formamide, containing 20% of the above polymer, 5% of N,N-diethylaminoethyl methacrylate and 5% of titanium dioxide (both based on the polymer), and a 27% solution in dimethyl formamide of the copolymer acrylonitrile/methyl acrylate/styrene sulphonic acid (93,6/6,0/0,4) are simultaneously extruded at 90 DEG C. through common orifices of a spinneret into a dry-spinning cell through which is passed a concurrent flow of gas at inlet temperature 300 DEG C. The resulting composite filaments are wound up and are then drawn to eight times their original length through baths of water at 95 DEG C. followed by a cell containing steam at atmospheric pressure. The yarn is allowed to shrink 50% in length in the steam cell and thus allow the acrylonitrile copolymer portion to relax. In another example, the nonelastomer component is spun from a solution containing a condensation polymer of m-phenylene diamine and isophthaloyl chloride. Specifications 461,236, 461,237, 578,079, 586,881, 597,368, 692,069, 711,279, 731,071, 849,154, 869,301 and U.S.A. Specifications 2,071,250, 2,190,770, 2,430,860, 2,527,300, 2,601,256, 2,706,674 and 2,731,446 are referred to.