Biaxially oriented polyester film
US4818581A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1987 |
| Grant date | Apr 4, 1989 |
| Priority date | — |
| Expiry date | Aug 26, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31786
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A biaxially oriented polyester film formed from an intimate mixture comprising (1) an aromatic polyester, and (2) 0.01 to 4% by weight, based on the aromatic polyester, of spherical fine particles of silica having (a) an average particle diameter of 0.05 to 4 .mu.m, (b) a particle diameter ratio, defined by the ratio of maximum diameter of minimum diameter, of from 1.0 to 1.2, and (c) a relative standard deviation (.sigma.) of particle size, of up to 0.5. A biaxially oriented polyester film formed from an intimate mixture comprising (1) an aromatic polyester, (2) 0.005 to 3% by weight, based on the aromatic polyester, of spherical fine particles of silica having the same properties as the above-mentioned (a), (b) and (c), and (3) 0.005 to 3% by weight, based on the aromatic polyester, of inert fine particles having an average particle diameter of 0.01 to 3 .mu.m and not exceeding the average particle diameter of the spherical fine particles of silica. The biaxially oriented films are useful for a magnetic recording medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.