GB1351304A - Acrylonitrile copolymers - Google Patents

Abstract

1351304 Production of acrylonitrile copolymers TORAY INDUSTRIES Inc 13 Aug 1971 [13 Aug 1970 30 Sept 1970 8 Oct 1970] 38071/71 Heading C3P An acrylonitrile polymer is formed by polymerizing a mixture of 80 wt. per cent or less of acrylonitrile, 80 wt. per cent or less of a monomer more hydrophobic than aerylonitrile and 10 wt. per cent or less of a monomer more hydrophilic than acrylonitrile in a medium which is a homogeneous mixture of dimethyl sulphoxide and water, so as to cause the copolymer to form an emulsion of non-agglomerated particles in the medium. The lower limits for the monomers are preferably 19À7 wt. per cent or more of acrylonitrile, 19À7 wt. per cent or more of the hydrophobic monomer and 0À3 wt. per cent or more of the hydrophilic monomer. The weight ratio of D.M.S.O. to water is preferably 85 : 15 to 60 : 40. Examples of the "hydrophobic monomer" are styrene, vinyl acetate and other vinyl esters, a vinyl ether, vinyl chloride, vinylidene chloride, methacrylonitrile, a C 5-8 alcohol ester of acrylic or methacrylic acid or a mixture of any of these. The hydrophilic monomer preferably contains a sulphonic acid group, or sulphonic acid salt group. Examples of such monomers are sulphoalkyl, sulphocyclohexyl, or sulphophenyl acrylates and methacrylates, styrene sulphonic acids, methallyl sulphonic acid, N-sulphophenyl methacrylamides, methallyl-sulphophenyl ethers; the Na, K or amine salts thereof, and mixtures thereof. A list of specific examples is given. The polymers are used to produce flame retarded fibres. The polymerization is carried out in the presence of the usual initiators (bisnitriles, peroxy compounds and redox systems).