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US4557982A
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Magnetic recording flexible disc
Assignee: Teijin Ltd
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Filing: 1984-04-06
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Granted: 1985-12-10
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Expires: 2004-04-06
Abstract
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 9×10 -6 to 35×10 -6 /°C., a maximum value of a humidity dependent expansion in the surface direction of the film is 0 to 8.0×10 -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 8.0×10 -6 /°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 3.0×10 -6 /% RH.
Inventors
- 👤 Hiroshi Nouda
- 👤 Kinji Hasegawa
- 👤 Masahiro Hosoi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:25
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/91; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31786
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
186 words
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 stretched in a longitudinal direction at a stretch ratio of 3.3 to 4.3 and stretched in a transverse direction at a stretch ratio of between 3.4 to 4.5, and consisting of poly 1,4-cyclo-hexylene dimethylene terephthalate wherein at least 90 mole % of a glycol component is 1,4-cyclohexane-dimethanol 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 9×10 -6 to 35×10 -6 /°C., a maximum value of a humidity dependent expansion in the surface direction of the film is 0 to 8.0×10 -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 8.0×10 -6 /°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 3.0×10 -6 /% RH.
Claim 2
Dependent Claim
186 words
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 stretched in a longitudinal direction at a stretch ratio of 3.3 to 4.3 and stretched in a transverse direction at a stretch ratio of between 3.4 to 4.5, and consisting of poly 1,4-cyclo-hexylene dimethylene terephthalate wherein at least 90 mole % of a glycol component is 1,4-cyclohexane-dimethanol 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 9×10 -6 to 35×10 -6 /°C., a maximum value of a humidity dependent expansion in the surface direction of the film is 0 to 8.0×10 -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 8.0×10 -6 /°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 3.0×10 -6 /% RH.
Claim 3
Dependent Claim
135 words
The magnetic recording flexible disc of claim 1 wherein the biaxially oriented film is characterized in that the maximum value of the temperature dependent expansion in the surface direction of the film is 20×10 -6 to 35×10 -6 /°C., the maximum value of the humidity dependent expansion in the surface direction of the film is 3 to 8.0×10 -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 6.0×10 -6 /°C., the difference between the maximum and minimum values of the humidity dependent expansion in the surface direction of the film is 0 to 3.0×10 -6 /% RH, the refractive index in the surface direction of the film is 1.585 to 1.650 and the density is 1.220 to 1.250.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-12-09 | 1989-06-10 | 1989-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-09 | 1993-06-10 | 1993-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-09 | 1997-06-10 | 1997-12-10 | $7700.00 | Window Closed / Lapsed |