Patent · US Expired

Multi-layer polyester film for magnetic tape

US4798759A · kind A · utility

31Cited by

18References

17Claims

0Family size

Assignee

Hoechst GmbH · DE

Inventors

Hermann Dallman · Niedernhausen, DE
Hartmut Hensel · Schlangenbad, DE
Werner Schafer · Essen, DE

Key dates

Filing date	Mar 13, 1987
Grant date	Jan 17, 1989
Priority date	—
Expiry date	Mar 13, 2007

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10T428/31786
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

A coextruded, biaxially draw-oriented, multi-layer polyester film as a base film for magnetic tape is described, whose characteristics are that the total thickness of the multi-layer film is no more than 10 .mu.m, the surface roughness of the base film on the side intended for the application of an information-carrying coating has an R.sub.a value (DIN 4768) of less than or equal to 0.010 .mu.m and the surface roughness of the opposite side of the base film which is not intended for application of an information-carrying coating, has an R.sub.a value of greater than 0.010 .mu.m and that the film has an E-modulus in the machine direction of greater than or equal to 6500 N/mm.sup.2.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.