Process for the preparation of heat resistant polyester film
US5545364A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 4, 1995 |
| Grant date | Aug 13, 1996 |
| Priority date | — |
| Expiry date | Oct 4, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2367/02
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A polyester film having excellent heat resistance and insulation property is produced by the inventive process which comprises: melt-extruding a polyester resin into a sheet, extending the sheet to shape it into a film and treating the film thermally to heat-set, wherein the polyester resin has an intrinsic viscosity of 0.7 to 0.75 dl/g and other portions which satisfy formula (1) and the thermal treatment is carried out so that formula (2) is satisfied: EQU [COOH]/[IV]<50 (1) EQU 1.0<S/D<1.2 (2) wherein: PA1 [COOH] represents the content (meq/10.sup.6) of terminal carboxyl groups in the polyester resin; PA1 [IV] represents the intrinsic viscosity (dl/g) of the polyester resin; PA1 S represents the X-ray crystal size (.ANG.) of the heat-set polyester film; and PA1 D represents the degree of crystallinity (%) of the heat-set polyester film.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.