THERMOPLASTIC POLYMER SHEET AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To produce a thermoplastic polymer sheet excellent in precision in thickness, not having die lines and sparingly causing a warp of the sheet. SOLUTION: This thermoplastic polymer sheet is produced by the melt extrusion of a thermoplastic polymer through a T-die or a coathanger die so as to form a sheet-like product, by transferring it while retaining the surface temperature difference between the front surface and the back one of a molten sheet within 15 deg.C and by subjecting the molten sheet to a cooling process to solidify it. The sheet is made of a thermoplastic polymer having >=150 deg.C glass transition temperature and has a sheet thickness of 150-1,000μm, an in-plane thickness tolerance (R max) of <=20μm, the sheet surface roughness of <=0.1μm and a sheet plane retardation of <=20 nm.