| 摘要 |
PROBLEM TO BE SOLVED: To obtain a mold-releasing polyphenylene sulfide film for liquid crystal membranes which can improve the surface defects of stripe roughness occurring on the melt molding with excellent heat resistance by arranging a melt-kneading mixer between the filter and the T die. SOLUTION: This film has an average surface roughness of 0.005-0.03μm and the uneven stripes occurring on the film surface having >=0.3μm height from the film base face at a rate of <=12/m, preferably the recurring units of the polyphenylene sulfide polymer comprising more than 98 mol% of the structural units shown by the formula, and the melt viscosity of 1,000-10,000 poise under the shearing rate of' 200 sec<-1> . This polymer is melt-kneaded and filtered through a filter in a melt extruder and extruded out of a die into a sheet, and biaxially oriented to give the objective film. In this process a mixer which can melt-knead the polymer is inserted between the filtration process and the T die. |
