| 摘要 |
A process for producing a polycarbonate film suitable for optical media applications having a birefringence of less than about 50 nm and low stress wherein the polycarbonate has a weight average molecular weight of about 30,000 or less and preferably 13,000 to about 25,000, extruding the polycarbonate film at a temperature of about 275° C. to about 360° C., the polycarbonate has a melt viscosity of about 100 to about 275 Pascal and a thickness of about 100 to about 600 mum, advancing the melted polymer film into a gap between two calendering rolls which calendaring rolls are at a temperature below the glass transition temperature, advancing the melted polycarbonate film through the gap and cooling the polycarbonate film wherein the polycarbonate film is extruded at the rate of about 10 to 100 feet per minute; and to a polycarbonate film prepared by the process above described.
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