POLYVINYL ALCOHOL-BASED FIBER HAVING EXCELLENT HOT WATER RESISTANCE AND PRODUCTION PROCESS THEREOF

摘要

A process for producing polyvinyl alcohol fibers by spinning a solution of a polyvinyl alcohol into a raw spun yarn and stretching the yarn at an overall draw ratio of 15 or above, wherein the raw yarn containing an acetal derived from an aliphatic dialdehyde having six or more carbon atoms as a crosslinking agent is subjected to dry heat stretching and then subjected to crosslinking with an acid under mild conditions. This process scarcely causes the thermal oxidation of the cross-linking agent in stretching or the scattering of the cross-linking agent in dry-heat stretching, and permits the penetration of the cross-linking agent inside the fibers to cross-link not only the fiber surface but also the inside thereof sufficiently, thus giving polyvinyl alcohol fibers having a high tenacity and a high resistance to moist heat.