GLOSS-STABLE MODACRYLIC FIBRES AND A PROCESS FOR THEIR PRODUCTION

The invention relates to gloss-stable modacrylic fibres and filaments comprising 50 % to 84 % of acrylonitrile, 15 % to 48 % of vinylidene chloride and 2 % to 5 % of an olefinically unsaturated sulphonic acid or salt thereof, all percentages being by weight, having a shrinkage in boiling water of at most 0.3 %, a reduction in density on treatment with boiling water of no more than 0.015 g/cc and a scattered light component after boiling of at most 35 units compared with a BaS04 standard of 1000 units, the increase brought about by treatment with boiling water amounting to no more than 30 units as well as to a process for their production. These fibres or filaments can be produced by dry-spinning a solution in a polar organic solvent of an appropriate copolymer with a K value according to Fikentscher of from 65 to 100, drying the filaments in the spinning duct to a residual solvent content of no less than 12 % by weight, based on the dry mass, subsequently drawing the filaments in water at 60 to 100.degree.C to between 1.8 and 7 times their original length, continuously drying at a temperature of 110 to 170.degree.C, with a permitted shrinkage of 0 to 40 % of the drawn length optionally cutting the filaments to fibers and fixing and stabilizing the resulting fibers or filaments by a steaming process carried out over a period of 2 to 10 minutes at a temperature of 105 to 120.degree.C with steam kept at a saturation concentration of 90 to 99 %.