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AssigneeSnia Viscosa S.p.A.
InventorsGiorgio Cazzaro, Giancarlo Matera, Antonino Cavallaro, Marina Zani
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Modacrylic fibres from acrylonitrile, vinylidene chloride, and a sulphonated comonomer, having reduced inflammability and high glossiness and dye yield are prepared by wet spinning a polyblend obtained by mixing two binary copolymers, the first from acrylonitrile and the sulphonated comonomer, and the second from acrylonitrile and vinylidene chloride. As the sulphonated comonomer, a significantly homopolymerizable monomer is used, viz. a monomer which homopolymerizes with a conversion of at least 30-40% by weight, in the presence of azobisisobutyronitrile catalyst, under given standard reaction conditions. Preferred sulphonated monomers are acid or salts of the acrylamidoalkanesulphonic series. The spinning dope is a polyblend solution in an organic solvent chosen among dimethylformamide, dimethylacetamide, and dimethylsulphoxide, mixed with water.
A process for preparation of the modacrylic fibres having reduced inflammability and high glossiness which comprises preparing a viscous solution of a mixture of a binary copolymer A containing from 88% to 98% of monomeric units derived from acrylonitrile and from 2 to 12% of monomeric units derived from a significantly homopolymerizable sulphonic acid monomer of the formula ##STR5## and salts of said acid, wherein R is hydrogen or a short chain alkyl radical and R.sub.2, R.sub.3, R.sub.4, R.sub.5, and R.sub.6 are each hydrogen or an alkyl, cyloalkyl or aryl radical, and a binary copolymer B containing from 55% to 88% of monomeric units derived from acrylonitrile and from 12% to 45% of monomeric units derived from vinylidene chloride in a spinning solvent, and spinning said viscous solution to form fibres containing from 12% to 40% by weight of copolymer A and 88% to 60% by weight of copolymer B.
Dependencies are inferred from the claim text.