POLYVINYL ALCOHOL FIBRIL WITH EXCELLENT WATER RESISTANCE AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain polyvinyl alcohol fibril with a high mechanical strength, elastic modules and resistance to water and alkali which is useful in manufacturing slate slabs and satisfies respective given valves of mean diameter and eluation ratio by incorporating a given amount of a vinyl alcohol-based polymer. SOLUTION: This fibril contains >=50wt.% of a vinyl alcohol-based polymer and comprises, for example, a blend of the vinyl alcohol-based polymer and a polyacrylonitrile-based polymer at the blending weigh ratio of (50:50) to (80:20). The mean diameter of the fibril is 0.1 to 5μm and the eluation ratio in hot water at 150 deg.C 0 to 30%. Preferably, this fibril is obtained by fibrillating a fibrilic fiber comprising a vinyl alcohol-based polymer as the ocean component and a polymer which is incompatible with the vinyl alcohol-based polymer as the island component and having a tenacity of >=3g/dr and then by crosslinking reaction (e.g. acetalization) of the fibril.