| 摘要 |
A process for the recovery of waste cellulosic textile fibres, which have previously been impregnated with a copolymer of vinyl chloride and methyl acrylate in which the vinyl chloride content is at least 70 per cent, consists in removing the copolymer by heating the waste textile at a temperature of 225-275 DEG F. for 3-5 hours with an aqueous solution containing at least 2 per cent of a dissolved aliphatic alcohol or ketone and at least 1.75 per cent of an alkali metal hydroxide, the ratio of the weights of treating solution to textile being at least 7 : 1. Any of the alcohols up to and including the butyl alcohols may be used, as may also iso-amyl, n-hexyl, and iso-octyl alcohols; suitable ketones are methyl ethyl ketone and methyl iso-butyl ketone. Dihydroxy alcohols such as ethylene and propylene glycols are also suitable. Preferably, the mixture is circulated in a closed kier at a temperature of 240-260 DEG F., the solution containing not more than 3 per cent of n-butyl or isopropyl alcohol and about 3 per cent of sodium or potassium hydroxide. Under these conditions, the polymer may be removed by the solution in 3 hours, and the comparatively low temperature prevents any appreciable degradation of the cellulose.ALSO:A process for the recovery of waste cellulosic textile fibres, which have previously been impregnated with a copolymer of vinyl chloride and methyl acrylate in which the vinyl chloride content is at least 70 per cent, comprises removing the copolymer by heating the waste textile at a temperature of 225-275 DEG F. for 3-5 hours with an aqueous solution containing at least 2 per cent of a dissolved aliphatic alcohol or ketone and at least 1.75 per cent of an alkali metal hydroxide, the ratio of the weights of treating solution to textile being at least 7 : 1. Any of the alcohols up to and including the butyl alcohols may be used, as may also isoamyl, n-hexyl, and iso-octyl alcohols; suitable ketones are methyl ethyl ketone and methyl iso-butyl ketone. Dihydroxy alcohols such as ethylene and propylene glycols are also suitable. Preferably, the mixture is circulated in a closed kier at a temperature of 240-260 DEG F., the solution containing not more than 3 per cent of n-butyl or iso-propyl alcohol and about 3 per cent of sodium or potassium hydroxide. Under these conditions the polymer may be removed by dissolution in 3 hours, and the comparatively low temperature prevents any appreciable degradation of the cellulose. |
