| 摘要 |
Fibres composed of at least 80 per cent by weight acrylonitrile and from 2 to 10 per cent of one of the polymers listed below are treated with a strong mineral acid before bleaching with an aqueous solution of sodium chlorite. The mineral acid may be sulphuric, nitric, hydrochloric, phosphoric or pyrophosphoric acid and may be at a concentration of 0.05 to 0.5 per cent by weight in aqueous solution and at a temperature of 185 DEG to 212 DEG F. The sodium chlorite may be at a concentration of 2.5 to 6.0 per cent by weight in aqueous solution at a temperature of 140 DEG to 180 DEG F. The minor component of the acrylonitrile fibre is derived from a N-hetero cyclic monomer such as alkyl substituted unsaturated imidazoles, benzimidazoles, imidazolines, oxazoles, benzoxazoles, benzothiazoles, pyridazines, pyrimidines, pyrazines, pyrazoles, pyrroles, triazines, quinolines, pyridines, thiazoles and lactams. The principal component may be a copolymer of acrylonitrile with one or more copolymerizable monomers of which many are specified. |
