Patent ID: 6833099
Filing Date: 2004-12-21
Classification: B29C,B29D,B29K,C08J,C09K,G02B,Y10T

Abstract:
A method of making a polyvinyl alcohol film, which comprises the steps of:preparing a film material containing polyvinyl alcohol, 0.01 to 1 part by weight of a nonionic surfactant relative to 100 parts by weight of the polyvinyl alcohol, and water, said film material having a volatile component in a quantity within the range of 50 to 90% by weight; and discharging the film material from a die of a flexible lip system onto a surface of a drum to form a polyvinyl alcohol film on said drum surface; wherein said polyvinyl alcohol film has a thickness within the range of 20 to 150 &mgr;m and also has a width of at least 2 m, a variance of said film thickness along the transverse direction being 0.5 &mgr;m/mm or less.