Method for producing low birefringence plastic film

摘要

In one embodiment, an extrusion process can comprise: feeding a thermoplastic polycarbonate resin to an extruder; heating the resin in the extruder to a melt temperature that is above a glass transition temperature of the resin, thereby producing a melt of the thermoplastic polycarbonate resin; extruding the melted resin downwardly through an extrusion nozzle orifice having a slot configuration; passing the melted resin downwardly into a gap between two calendering rolls at least one of which has a highly polished surface, and wherein the calendering rolls are maintained at a roll temperature of less than the glass transition temperature; and cooling the thermoplastic polycarbonate resin film to below its glass transition temperature as the thermoplastic polycarbonate resin film advances through the gap.