| 摘要 |
1,102,771. Producing stereoregular polyvinyl alcohol fibres. MONSANTO CO. 8 April, 1965 [8 April, 1964], No. 14981/65. Heading B5B. Stereoregular polyvinyl alcohol filaments which are insoluble in boiling water are produced by wet or dry spinning a solution of a stereoregular polyvinyl ester of a halogenated acetic acid, in which all three hydrogen atoms of the methyl group in the acetic acid have been substituted by either chlorine or fluorine or by both fluorine and chlorine, and continuously hydrolysing the resulting filaments. The filaments are preferably formed by wet spinning, and the thus formed filaments, stretched, hydrolysed continuously, dried and hot drawn. The spinning solution may contain 12 to 40% by weight of the polyester dissolved in an organic oxygen-containing liquid and may be extruded into a coagulation liquid which is a non-solvent for the polymer but miscible with the spinning solution solvent. The filaments may be stretched immediately after hydrolysis. The organic oxygen containing liquid may be acetone, methyl ethyl ketone, tetrahydrofuran or dimethylacetamide. The coagulating bath may be aqueous. The filaments may be hydrolysed with a base having a pKb value less than 8À0, such as ammonium hydroxide, methanolic ammonia, tetramethyl ammonium hydroxide or a primary or secondary amine. The freshly extruded polyester filaments may be stretched at a draw ratio of 1À05 to 8À0 : 1À0 in a hot aqueous bath, and may be further stretched immediately after hydrolysis. They may then be dried by passing them over a roller maintained at a temperature of from 80‹ to 110‹ C. and finally drawn over a heated surface while stretching them at a stretch ratio of from 1À1 to 5À0 : 1À0. The ester spun may be vinyltrifluoro or chlorodofluoroacetate. |
