| 摘要 |
A spinning solution comprises a vinyl chloride polymer in a ternary solvent mixture comprising (a) one or more liquid chlorine-substituted aliphatic and/or aromatic hydrocarbons, (b) one or more liquid aliphatic and/or aromatic nitro compounds and (c) one or more aliphatic, cycloaliphatic and/or aromatic ketones. Mixtures of solvents within each of the classes (a), (b) and (c) may be used, such mixtures ranking as a single component of the ternary mixture. Specified solvents of the three classes are:- (a) methylene dichloride, chlorobenzenes and tri- and per-chloroethylene; (b) nitromethane, nitropropane and nitrobenzenes; and (c) acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 2-butanone, and acetophenone. In examples various mixtures of the above-mentioned compounds are used to dissolve suspension polyvinyl chloride having a K-value of 67,5. The resulting solutions at 5% concentration have viscosities ranging from 12,2 to 17,7 Cp. at 25 DEG C. The solutions are spun by extrusion through a spinneret having 64 holes of 80 m diameter at a head temperature of 82 DEG C. and column temperatures ranging from 100 DEG to 117 DEG C. and the fibres stretched at a ratio of 1:4,2. Specification 825,032 is referred to.
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