Patent US4670319A successfully refreshed from Google Patents.
US4670319A
Expired / Lapsed
US
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Polyester film for magnetic recording media
Assignee: Teijin Ltd
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Filing: 1986-05-29
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Granted: 1987-06-02
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Expires: 2006-05-29
Abstract
Abstract A biaxially oriented polyester film for use in thin metallic film-type magnetic recording media, said polyester film having a first surface to which a thin metallic film as a magnetic recording layer is to be applied and a second surface coated with an easily slippable layer composed of an organic polymeric binder and inert fine solid particles dispersed therein, the first surface having (a) large protrusions with a diameter of 0.2 to 2 micrometers and a height of 20 to 200 angstrom distributed at a density of at least 10 3 but less than 10 6 per mm 2 , and (b) small protrusions with a diameter of 0.01 to 0.1 micrometer and a height of 10 to 100 angstrom distributed at a density of from 10 6 up to 10 9 .
Inventors
- 👤 Hideo Katoh
- 👤 Kinji Hasegawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:18
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/735; B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B32B27/36; G11B5/7356; G11B5/7358; G11B5/739; G11B5/73923; G11B5/73927; G11B5/73935; B32B2255/00; B32B2255/20; B32B2255/205; B32B2307/00; B32B2307/20; B32B2307/208; B32B2429/00; B32B2429/02; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/91; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/24372; Y10T428/25; Y10T428/31504; Y10T428/31786
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
136 words
A biaxially oriented polyester film for use in thin metallic film-type magnetic recording media, said polyester film having a first surface to which a thin metallic film as a magnetic recording layer is to be applied and a second surface coated with an easily slippable layer composed of an organic polymeric binder and inert fine solid particles dispersed therein, the first surface having (a) large protrusions with a diameter of 0.2 to 2 micrometers and a height of 20 to 200 angstrom distributed at a density of at least 10 3 but less than 10 6 per mm 2 , and (b) small protrusions with a diameter of 0.01 to 0.1 micrometer and a height of 10 to 100 angstrom distributed at a density of from 10 6 up to 10 9 per mm 2 .
Claim 2
Dependent Claim
136 words
A biaxially oriented polyester film for use in thin metallic film-type magnetic recording media, said polyester film having a first surface to which a thin metallic film as a magnetic recording layer is to be applied and a second surface coated with an easily slippable layer composed of an organic polymeric binder and inert fine solid particles dispersed therein, the first surface having (a) large protrusions with a diameter of 0.2 to 2 micrometers and a height of 20 to 200 angstrom distributed at a density of at least 10 3 but less than 10 6 per mm 2 , and (b) small protrusions with a diameter of 0.01 to 0.1 micrometer and a height of 10 to 100 angstrom distributed at a density of from 10 6 up to 10 9 per mm 2 .
Claim 3
Dependent Claim
41 words
The film of claim 1 wherein the large protrusions have a diameter of 0.5 to 2 micrometers and a height of 50 to 200 angstrom and are distributed at a density of 10 4 to 10 5 per mm 2 .
Claim 4
Dependent Claim
39 words
The film of claim 1 wherein the small protrusions have a diameter of 0.05 to 0.1 micrometer and a height of 10 to 100 angstrom distributed at a density of 10 7 to 10 8 per mm 2 .
Claim 5
Dependent Claim
30 words
The film of claim 1 wherein the large protrusions are given by inert solid fine particles having an average particle diameter of 0.05 to 0.5 micrometer dispersed in the film.
Claim 6
Dependent Claim
40 words
The film of claim 1 wherein the small protrusions are formed by coating the first surface with a coating composition comprising inert solid fine particles having an average particle diameter of 0.01 to 0.1 micrometer and an organic polymeric binder.
Claim 7
Dependent Claim
42 words
The film of claim 1 wherein the easily slippable layer on the second surface has a surface roughness represented by its center line average roughness Ra of 0.002 to 0.01 micrometer and its 10-point average roughness Rz of 0.01 to 0.1 micrometer.
Claim 8
Dependent Claim
29 words
The film of claim 1 wherein the easily slippable layer on the second surface has a surface with network-like fine protrusions having a height of 200 to 600 angstrom.
Claim 9
Dependent Claim
32 words
The film of claim 1 which has a Young's modulus in the longitudinal direction of at least 550 kg/mm 2 and a heat shrinkage in the transverse direction of 1 to 5%.
Claim 10
Dependent Claim
23 words
A magnetic recording medium composed of the polyester film of claim 1 and a ferromagnetic thin metallic film applied to its first surface.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-01 | 1990-12-01 | 1991-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-01 | 1994-12-01 | 1995-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-01 | 1998-12-01 | 1999-06-02 | $7700.00 | Window Closed / Lapsed |