METHOD OF MANUFACTURING HYDRATED POLYVINYL ACETAL RESIN FILM

摘要

PROBLEM TO BE SOLVED: To provide a method of manufacturing a hydrated polyvinyl acetal resin film having a high hydrating rate and high productivity. SOLUTION: The method of manufacturing a hydrated polyvinyl acetal resin film comprises melt-extruding a polyvinyl acetal resin containing a plasticizer into a film from an extruder and immersing the polyvinyl acetal resin film 1 below 250°C in a water vessel 3 at≥20°C to produce a water content of the film of≥0.23 wt.%. Before or after immersion of the polyvinyl acetal resin film in water at≥20°C, warm water or steam is sprayed on the film. COPYRIGHT: (C)2008,JPO&INPIT