Patent ID: 6623679
Filing Date: 2003-09-23
Classification: B29C,B29K,C08J,G03C

Abstract:
A method for controlling the width of a polyester film support comprising, in order, the steps of:(a) extruding a polyester resin using one or more extruders; (b) casting the resin on a casting wheel to form a polyester sheet; (c) stretching the polyester sheet along the machine direction by ratios of 3 to 5 times at temperatures ranging from above the glass transition temperature to below the thermal crystallization temperature, wherein the machine contains extended edge rollers (14) installed in the drafter at the point where stretching occurs for the purpose of narrowing the width of the polyester sheet during the machine stretch as it passes along the drafter; (d) stretching the polyester sheet along the transverse direction by ratios of 3 to 5 times at temperatures ranging from above the glass transition temperature to below the thermal crystallization temperature; and (e) heat setting the polyester sheet at temperatures ranging from 180 to 250Â° C.