Magnetic recording flexible disc
US4557982A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 6, 1984 |
| Grant date | Dec 10, 1985 |
| Priority date | — |
| Expiry date | Apr 6, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31786
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic recording flexible disc composed of a polyester film substrate having formed thereon a magnetic layer, the improvement wherein said polyester film is a biaxially oriented film consisting of poly-1,4-cyclohexylene dimethylene terephthalate wherein at least 90 mole % of a glycol component is 1,4-cyclohexanedimethanol and at least 80 mole % of an acid component is terephthalic acid, a maximum value of a temperature dependent expansion in the surface direction of the film is 9.times.10.sup.-6 to 35.times.10.sup.-6 /.degree.C., a maximum value of a humidity dependent expansion in the surface direction of the film is 0 to 8.0.times.10.sup.-6 /% RH, the difference between the maximum and minimum values of the temperature dependent expansion in the surface direction of the film is 0 to 8.0.times.10.sup.-6 /.degree.C., and the difference between the maximum and minimum values of the humidity dependent expansion in the surface direction of the film is 0 to 3.0.times.10.sup.-6 /% RH.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.