Biaxially oriented polyester film
US4725472A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 14, 1987 |
| Grant date | Feb 16, 1988 |
| Priority date | — |
| Expiry date | Jan 14, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31786
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A biaxially oriented polyester film is provided, which has a plurality of depressions and a plurality of protrusions on at least one surface thereof, in a configuration such that at least one protrusion exists within each depression or at least protrusion exists in the area where two or more depressions are contiguous to each other depressions having an area fraction of from 1.times.10.sup.-3 to 6.times.10.sup.-1. The polyester film is useful as a substrate for magnetic recording tapes such as audio and video tapes, and the resultant magnetic recording tapes are excellent in both electromagnetic transducing characteristics and runnability.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.