| 摘要 |
An acrylonitrile polymer solution is forced through a shaped orifice into a gaseous medium in which only a small amount of solvent is evaporated, directed into a coagulating bath comprising a liquid which is a precipitant for the polymer and an extractant for the solvent; the thus-formed filament is stretched in presence of said liquid, withdrawn, passed through a second liquid and stretched therein to orient the polymer molecules and then allowed to relax and shrink. The polymer may be polyacrylonitrile, at least 80% acrylonitrile copolymerized with up to 20% of a mono-olefinic monomer such as vinyl acetate (the Specification lists other comonomers) or a blend of (a) such a copolymer containing up to 99% acrylonitrile and (b) a copolymer of 10-70% acrylonitrile and 30-90% vinyl-substituted tertiary heterocyclic amine (e.g. 2-methyl-5-vinylpyridine) the blend having an overall content of said amine of 2-10%. Specification 824,168 is referred to.
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