| 摘要 |
Colour is removed from articles such as fibres, yarn, films and straws composed of a polymer or copolymer of acrylonitrile containing at least 85 per cent acrylonitrile by treating the dry article with an aqueous solution of hypochlorous acid in a concentration equivalent to 0.05 to 1.0 per cent available chlorine at a temperature between 90 DEG and 150 DEG C. and a pressure sufficiently high to maintain the treating solution liquid. Copolymers specified are those with vinyl acetate or chloride, acrylic acid or esters thereof, styrene, butadiene and isobutylene. The articles may be obtained by dry spinning from solution in such as dimethyl formamide or by wet spinning and subsequently drying.ALSO:Colour is removed from articles such as fibres, yarn, films and straws composed of a polymer or copolymer of acrylonitrile containing at least 85 per cent acrylonitrile by treating the dry article with an aqueous solution of hypochlorous acid in a concentration equivalent to 0.05 to 1.0 per cent available chlorine at a temperature between 90 DEG and 150 DEG C. and a pressure sufficiently high to maintain the treating solution liquid. Copolymers specified are those with vinyl acetate or chloride, acrylic acid or esters thereof, styrene, butadiene and isobutylene. The articles may be obtained by dry spinning from solution in such as dimethyl formamide or by wet spinning and subsequently drying. |
