Heat-shrinkable polyester film and process for production thereof
US7829655B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 2007 |
| Grant date | Nov 9, 2010 |
| Priority date | — |
| Expiry date | Jun 13, 2027 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31786
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In the heat-shrinkable polyester film of the present invention, the main shrinkage direction is the longitudinal direction. In addition, the hot-water heat shrinkage ratios in the longitudinal direction and the width direction when the film is treated in hot water at 90° C. for 10 seconds, the refractive indexes in the longitudinal direction and the width direction and the natural shrinkage ratio after aging at 40° C. and 65% RH for 700 hours or more are each controlled in predetermined ranges. The heat-shrinkable polyester film of the present invention is manufactured by stretching an unstretched film at a ratio of 2.5 times or more and 6.0 times or less in the width direction at a temperature of Tg+5° C. or more and Tg+40° C. or less, passing the film in an intermediate zone that does not execute an active heating operation, heat-treating the film at a temperature of 100° C. or more and 170° C. or less over a period of 1.0 second or more and 10.0 seconds or less, cooling the film to a surface temperature of 30° C. or more and 70° C. or less, stretching the film at a ratio of 2.0 times or more and 7 times or less in the longitudinal direction at a temperature of Tg+5° C. or more a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.