METHOD FOR MANUFACTURING POLYVINYL ALCOHOL FILM

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a film free from defects such as streak without the corrosion of an extrusion die and the retention or adhesion of a resin on a runner surface, in the manufacture of the film by extruding a polyvinyl alcohol resin. SOLUTION: The extrusion die is constituted of a material composed mainly of iron, containing 0.2-0.6 wt.% of carbon element.