| 摘要 |
Oriented polyvinyl alcohol shaped articles such as fibres, bristles, tubes and rods, having improved dyeability comprise at least 30% by weight of units of vinyl alcohol or acetalized vinyl alcohol and having substantially uniformly distributed therein molecules of an N-vinyl amide group containing water-soluble polymer prepared by polymerizing an N-vinyl amide group containing monomer, the nitrogen content of said shaped article being in the range of 0.1 to 5% by weight all weight percentages being calculated to the basis of nonacetalized vinyl alcohol units. The polyvinyl alcohol preferably has a degree of polymerization in the range 1,000-3,000. The watersoluble polymeric amides may be derived from N-vinyl pyrrolidone; 1-vinyl-5-methyl-2-pyrrolidone; 1 - vinyl - 4 - ethyl - 2 - pyrrolidone; 1 - vinyl - 5 - ethyl - 2 - pyrrolidone; N - vinyl caprolactam; N-vinyl valerolactam; N-vinyl acetamide; or N-vinyl butyramide. These amides may be copolymerized with vinyl acetate, vinyl propionate, acrylonitrile, acrylic acid, methyl acrylate, methacrylamide, maleic anhydride, styrene, vinyl chloride, vinyl methyl ketone, or vinyl methyl ether. After the article has been formed from the aqueous spinning solution insolubilization can be effected by the use of formaldehyde, chloroacetaldehyde, butyl aldehyde, benzaldehyde, glyoxal, terephthalic aldehyde, or with titanium sulphate or a chromate. The spinning solution may be extruded into air or nitrogen at a temperature of 50-180 DEG C. in dry-spinning techniques or into a concentrated aqueous solution of sodium sulphate or ammonium sulphate at a temperature of 25-60 DEG C. in wet-spinning processes. The filaments may then be stretched to a draw ratio of 2 : 1 to 12 : 1 and then treated in air at 210-250 DEG C. for 2 seconds to 5 minutes to give a wet-softening temperature higher than 60 DEG C. and then acetalized to the extent of 5-60% of the polyvinyl alcohol hydroxyl groups.
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