PROCESS FOR EXPANDING ANNEALED THERMOFORMABLE MATERIAL

摘要

1424336 Sheet forming UNION CARBIDE CORP 28 Dec 1972 [29 Dec 1971] 59902/72 Heading B5A The blank described in Specification 1,424,334 is annealed prior to the expansion of its crosssection, e.g. at a temperature from about 10‹ C. below the heat distortion temperature of the plastics up to the melt temperature of the plastics, for a period of about 5 to 240 minutes.