PREPARATION OF FILM

• Main Authors: OKI HIROYUKI, TERADA KAZUTOSHI
• Format: Patent
• Language: English
• Published: 25.05.1999
• Edition: 6
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP

PROBLEM TO BE SOLVED: To easily obtain a film exhibiting remarkably improved water resistance and moist heat resistance while maintaining dynamic and mechanical properties by a process to prepare a film consisting of a polyvinyl alcohol based polymer where a specific amount of a specific polyhydric ethanol compound is incorporated into or adhered to the film, which is then heated thereby causing the crosslinking of the polymer. SOLUTION: In the process to prepare a film, a polyhydric ethanol compound containing two or more of ethanol structures adjacent to an electron- withdrawing group is incorporated into or adhered to the film in an amount ranging from 0.05 to 20 mole % based on the recurring unit of the polyvinyl alcohol based polymer, and subsequently the polymer is crosslinked by heat treatment. As the polyhydric ethanol compound is preferable a compound of formula I or II (wherein A and A' are each an electron-withdrawing linking group selected from carbonyl, sulfinyl, sulfonyl and phosphonyl groups; and X is a divalent hydrocarbyl group optionally containing an oxygen or nitrogen atom). Preferably the polyvinyl alcohol based polymer has an average polymerization degree of 1,000 or more and a saponification degree of 70 mole % or more.