Biaxially oriented polyester film for a membrane switch
US6139952A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1999 |
| Grant date | Oct 31, 2000 |
| Priority date | — |
| Expiry date | Sep 16, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/27
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A biaxially oriented polyester film for a membrane switch, which is made from a polyester containing at least 80 mol % of ethylene-2,6-naphthalene dicarboxylate recurring units and which has an endothermic peak with an endothermic energy of at least 0.4 mJ/mg at a temperature of 110 to 160.degree. C. This film is produced by subjecting a biaxially oriented polyester film produced from the above polyester in accordance with a method known per se to the following steps in the order named: PA1 (1) the step of heating the film under no strain at a temperature of 150 to 180.degree. C. for 1 to 5 hours; and PA1 (2) the step of heating the film in an unrolled or rolled state at a temperature of 80 to 122.degree. C. for 5 to 200 hours.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.