| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a high-quality water-soluble polyvinyl alcohol fiber excellent in uniformity without causing loops or fluffs and unevenness of fineness at a low cost. SOLUTION: A PVA comprising (A) a PVA having 330 viscosity-average degree of polymerization, 98.4 mol% degree of saponification, 83 mol% molar fraction of the central hydroxyl group of a three successive hydroxyl group chain according to the triad expression based on vinyl alcohol units and 206 deg.C melting point and containing 0.03 pt.wt. of sodium ions based on 100 pts.wt. of the PVA (A) and further 0.5 wt.% of titanium oxide fine particles having 0.4μm average particle diameter is melt spun from a spinneret and taken off at >=3,000 m/min takeoff speed. In the process, spinning is carried out so that the residence time(t) (min), the process temperature T ( deg.C) and the spinning speed V (m/min) of the PVA in a spinning apparatus satisfy the following formulae: 20<=t+T/10<=45 and 10<=Vt×10-3<=80.
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