Polyester film and magnetic recording medium
US5047278A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 6, 1989 |
| Grant date | Sep 10, 1991 |
| Priority date | — |
| Expiry date | Jan 6, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31786
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A polyester which is prepared by using a germanium compound as the polymerization catalyst, in which the Young's modulus E.sub.MD in the machine direction and the Young's modulus E.sub.TD in the transverse direction satisfy the requirements of E.sub.MD .gtoreq.350 kg/mm.sup.2, E.sub.TD .gtoreq.350 km/mm.sup.2 and E.sub.MD .times.E.sub.TD .gtoreq.250,000 kg.sup.2 /mm.sup.4, the refractive index n.sub.ZD in the thickness direction satisfies the requirement of 1.480.gtoreq.n.sub.ZD .gtoreq.1.492, and the maximum roughness Rt of at least one surface satisfies the requirement of Rt.gtoreq.100 nm, is valuable as a base film for a magnetic recording medium. A laminate structure of a polyester layer A and a polyester layer B is also used as a base film for a magnetic recording medium, in which the above requirements of E.sub.MD, E.sub.tD and n.sub.ZD are satisified, fine particles are incorporated in the layer B, the outer surface of the layer A satisfies the requirement of Rt .gtoreq.100 nm and Rt of the outer surface of the layer B is in the range of from 30 to 150 nm. A magnetic recording medium having a ferromagnetic metal thin film formed thereon, which is prepared by using this polye…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.