Films and sheets of polyester-polycarbonate blends
US3956229A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 16, 1974 |
| Grant date | May 11, 1976 |
| Priority date | — |
| Expiry date | Jul 16, 1994 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S260/35
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
This invention provides a film or sheet capable of being thermoformed into a shaped article and being formed from a blend of about 60 to 85 parts by weight of a polyethylene terephthalate polymer having an intrinsic viscosity of at least about 0.90 and correspondingly about 40 to 15 parts by weight of a polycarbonate polymer, the polyethylene terephthalate portion of the film or sheet having a degree of crystallinity in the range of about 20 to 40%. The film is essentially non-oriented. The present invention also provides shaped articles thermoformed from such film or sheet, such as cook-in-trays. Moreover, this invention provides a process of forming such film or sheet which comprises the steps of blending about 60 to 85 parts by weight of a polyethylene terephthalate polymer having an intrinsic viscosity of at least about 0.90 with correspondingly about 40 to 15 parts by weight of a polycarbonate resin, extruding the resultant blend at a temperature of above about 500.degree.F onto a moving support such as a casting roll while maintaining the surface of the support at a temperature of about 225.degree. to 380.degree.F whereby a film or sheet of the blend is formed, and collecting…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.