GB712999A - Improvements in or relating to acrylonitrile polymer solutions - Google Patents

Abstract

Solutions suitable for the manufacture of fibres and filaments comprise an acrylonitrile polymer dissolved in an anhydrous mixture comprising 60-95 per cent. by weight if nitromethane and 40-50 per cent. by weight of one or more compounds selected from lactones of hydroxy-fatty acids, alkylene cyclic carbonates, cyclic anhydrides of saturated aliphatic dicarboxylic acids, beta-nitro-and -cyano-ethanols, nitro- and cyano-substituted higher homologues of ethanol containing one further polar substituent atom or group for each carbon atom in excess of two in the nitro- or cyano-substituted alkanol, and unsaturated aliphatic acids of dissociation constant above 2 x 10-3 at 25 DEG C.; or a mixture comprising less than 50 per cent. by weight of nitromethane and more than 50 per cent. by weight of a cyclic anhydride of an aliphatic unsaturated dicarboxylic acid. Compounds specified are butyrolactone, valerolactone, glycol carbonate, succinic, glutaric and maleic anhydrides, 3-hydroxy- 2-chloro-propionitrile, 3 - chloro - 2 - hydroxy - propionitrile, 3, 3 - dichloro - 2 - methyl - 2 - hydroxy - propionitrile, and maleic acid. The acrylonitrile polymer may be polycrylonitrile and copolymers of acrylonitrile with vinyl chloride, vinylidene chloride, vinyl acetate, methyl or phenyl acrylate, or styrene. The fibres and films may be made by dry or wet-spinning or wet-casting techniques such as those described in Specification 712,984 and the fibres oriented by stretching, e.g. as described in Specification 636,476. The solutions may also be used in the production of coatings. Specifications 676,889 and 712,998 also are referred to.