Transparent sheets and containers formed from polycarbonate-polyester blends and formation thereof

摘要

A sheet formed from a uniform blend of from about 80 to 97% by weight of polyethylene terephthalate having an intrinsic viscosity of above about 0.9 and a melt viscosity at 525 DEG F. of above about 10,000 poises and correspondingly from about 20 to 3% by weight of a polycarbonate resin having an intrinsic viscosity of about 0.4 to 0.6 and a melt viscosity at 500 DEG F. of less than 50,000 poises; said sheet having a haze value as determined by ASTM D-1003 of less than about 2% and being essentially amorphous and non-oriented. Also disclosed is a process for forming a sheet which comprises uniformly blending the composition, extruding the composition into a sheet at a temperature between about 490 DEG to 530 DEG F. and rapidly cooling the sheet by contact with at least one cooling surface maintained at a surface temperature in the range of about 50 DEG to 160 DEG F. for a period of time not exceeding about 15 seconds. Containers may be formed from such sheets by a thermoforming step at temperatures in the range of about 210 DEG to 280 DEG F.