PRODUCTION OF POLYVINYL ALCOHOL TYPE PERM SELECTIVE MEMBRANE

摘要

PURPOSE:To provide a membrane of superior pressure resistance and flexibility by treating a PVA type permeation membrane having specific properties with an inorg. acid then subjecting the same to a hot air treatment. CONSTITUTION:A polyvinyl alcohol type permeable membrane having =30mol% degree of acetal conversion in molecules and the degree of crosslinking by acetal conversion of =30min dissolution time in a 65% nitric acid is treated with an aq. inorg. soln., thence it is subjected to a hot air treatment. Here, the aq. inorg. soln. of a sulfuric acid or the like is 0.1-2wt% inorg. acid concns. and the temp. of the hot air treatment is 100-160 deg.C.