Biaxially oriented polyester film
US5196472A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 26, 1991 |
| Grant date | Mar 23, 1993 |
| Priority date | — |
| Expiry date | Nov 26, 2011 |
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 aromatic polyester composition containing: PA1 (A) 100 parts by weight of an aromatic polyester, and PA1 (B) 0.005 to 5 parts by weight of calcium carbonate particles defined by: PA1 (a) a length/width ratio (2a/2b) in the range of from 1.25 to 3, PA1 (b) an average particle diameter (D), as a diameter of a circle converted from an area, in the range of from 0.05 to 5 .mu.m, and PA1 (c) an ellipse coefficient, represented by the following equation (1), in the range of from 0.7 to 1.2, ##EQU1## wherein R is an ellipse coefficient, S.sub.1 is an observed area of a projected plane of a particle, and S.sub.2 is an elliptical area determined on the basis of observed values of the length (2a) and width (2b); and a magnetic recording medium formed of the above biaxially oriented polyester film and a magnetic layer formed thereon.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.