Flame-resistant modacrylic fibers and filaments having improved thermostability and process for their manufacture

Abstract From the Canadian patent

The invention provides filaments and fibers on the basis of modacrylic polymers wherein the fiber-forming substance comprises a copolymer of, 35 to 85% by weight of acrylonitrile 5 to 45% by weight of vinyl chloride, vinyl bromide vinyli-, dene chloride or a mixture thereof and, 5 to 30% by weight of a carboxyphosphinic acid derivative of the formula, in which R1 and R2 represent alkyl or haloalkyl radicals having at most carbon atoms, R3 stands for a hydrogen atom or a methyl group X represents an oxygen or a sulfur atom and Y is an optionally branched alkylene group having from 1 to 6 carbon atoms, and 0 to 15% by weight of other unsaturated compounds with activated double bond, and a …