Polyester film having specific surface properties
US5271985A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 30, 1991 |
| Grant date | Dec 21, 1993 |
| Priority date | — |
| Expiry date | Jul 30, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
This invention relates to a polyester film suited for use in optical recording medium. The polyester film of the present invention has a modulus of photoelasticity of not more than 0.9.times.10.sup.-3 mm.sup.2 /kgf, a maximum surface roughness Rt of not more than 100 nm and a mean interval Sm between adjacent surface projections of not less than 20 .mu.m, so that light scattering and interference are not caused, and optical strain is not generated even when a thermal stress or external force is exerted to the film. Thus, the polyester film of the present invention can be used as the supporting layer or cover layer of optical recording media such as optical cards, optical disks and optical recording tapes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.