| 摘要 |
Artificial threads (including artificial silk filaments and staple fibre) are obtained by a process in which cellulose xanthate is directly reacted in presence of an inert solvent with a substance which is able to react with the hydroxyl groups of the cellulose xanthate molecules so as to cause the groups to be replaced by organic groups or radicals while retaining the fibrous structure of the cellulose xanthate, and the reaction product is dissolved in water or dilute caustic soda solution and spun into the form of threads. The substance which is caused to react with the cellulose xanthate may be acrylonitrile, chlorocarbonic acid methyl ester, phosgene, chloracetic acid or chloracetic acid methyl ester. In an example, fibrous cellulose xanthate having a gamma value of 46.2 is shaken with a solution of acrylonitrile in diethyl ether for 6 hours at 12-14 DEG C. The ether solution is poured off and the reaction product is dissolved directly to form a viscose of 7.5 per cent cellulose and 6.5 per cent caustic soda and is extruded into a coagulating bath to form threads. The degree of substitution of the cellulose by organic groups or radicals may be controlled by adjustment of the concentration of the acrylonitrile or other reagent in the inert solvent or by adjustment of the gamma value of the xanthate.
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