Transparent sheets and containers formed from polycarbonate-polyester blends and formation thereof
US4230656A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 1978 |
| Grant date | Oct 28, 1980 |
| Priority date | — |
| Expiry date | May 15, 1998 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/9135
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
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.degree. 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.degree. 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.degree. to 530.degree. 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.degree. to 160.degree. 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.degree. to 280.degree. F.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.