PURPOSE: To obtain polyvinyl alcoholic fiber suitable as a reinforcing agent for rubber, plastics or cement or industrial materials such as ropes, fishing nets or civil engineering sheets usable even in environment exposed to high temperatures or water for a long period.
CONSTITUTION: The objective polyvinyl alcoholic fiber is modified with a compound having a group expressed by formula I (M is metal having chelating ability; R is alkyl) or has a compound, having the group and applied thereto. This fiber is obtained by spinning a polyvinyl alcoholic polymer having ≥1500, especially ≥10000 viscosity-average polymerization degree, applying a chelate compound expressed by formula II (X1 to X4 are halogen or OH) in an amount of 0.01-1.0wt.%, preferably 0.03-0.5wt.% expressed in terms of the metal based on the fiber to the resultant spun raw yarn or its drawn yarn and then drawing or heat-treating the obtained yarn at 150-260°C temperature. Cr and Al are especially preferred as the metal having the chelating ability. In the case of the Cr, the stability of the chelate compound is excellent. In the case of the Al, the resultant fiber is hardly colored.
YOSHIMOCHI TOSHIMI
SATO MASAHIRO
