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Patent US4737415A successfully refreshed from Google Patents.
US4737415A
Expired / Lapsed
US
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Magnetic recording medium and production thereof
Assignee: Maxell Ltd
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Filing: 1985-11-20
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Granted: 1988-04-12
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Expires: 2005-11-20
Abstract
Abstract A magnetic recording medium comprising a substrate, a magnetic layer and a protective layer which consists of an organic polymeric material comprising carbon atoms, hydrogen atoms and oxygen atoms, the content of the oxygen atoms increasing towards the outer surface of the protective layer, which has improved durability and corrosion resistance.
Inventors
- 👤 Minoru Ichijo
- 👤 Tsunemi Ohiwa
- 👤 Fumio Kokai
- 👤 Takashi Kubota
- 👤 Kunio Wakai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:05
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/722; G11B5/84; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31652; Y10T428/31663
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
57 words
A magnetic recording medium comprising a substrate, a magnetic layer and a first protective layer which consists of an organic polymeric material comprising carbon atoms, hydrogen atoms and oxygen atoms, the content of the oxygen atom increasing towards the outer surface of the protective layer, the thickness of the protective layer ranging from 20 to 2,000 Å.
Claim 2
Dependent Claim
57 words
A magnetic recording medium comprising a substrate, a magnetic layer and a first protective layer which consists of an organic polymeric material comprising carbon atoms, hydrogen atoms and oxygen atoms, the content of the oxygen atom increasing towards the outer surface of the protective layer, the thickness of the protective layer ranging from 20 to 2,000 Å.
Claim 3
Dependent Claim
39 words
A magnetic recording medium according to claim 1, wherein the oxygen content within a 20 Å thickness at the surface of said first protective layer is from 5 to 70% by weight of the organic polymer in said thickness.
Claim 4
Dependent Claim
25 words
A magnetic recording medium according to claim 2, wherein the oxygen content in the whole first protective layer is from 5 to 50% by weight.
Claim 5
Dependent Claim
89 words
A magnetic recording medium comprising a substrate, a magnetic layer, a first protective layer which consists of an organic polymeric material comprising carbon atoms, hydrogen atoms and oxygen atoms, the content of the oxygen atom increasing towards the outer surface of the protective layer, wherein the oxygen content within a 20 Å thickness at the surface of the first protective layer is from 5 to 70% by weight of the organic polymer in said thickness and a second protective layer of a lubricant formed on said first protective layer.
Claim 6
Dependent Claim
89 words
A magnetic recording medium comprising a substrate, a magnetic layer, a first protective layer which consists of an organic polymeric material comprising carbon atoms, hydrogen atoms and oxygen atoms, the content of the oxygen atom increasing towards the outer surface of the protective layer, wherein the oxygen content within a 20 Å thickness at the surface of the first protective layer is from 5 to 70% by weight of the organic polymer in said thickness and a second protective layer of a lubricant formed on said first protective layer.
Claim 7
Dependent Claim
21 words
A magnetic recording medium according to claim 1, wherein said organic polymeric material constituting the protective layer further comprises silicon atoms.
Claim 8
Dependent Claim
17 words
A magnetic recording medium according to claim 1, wherein said organic polymeric material further comprises metal atoms.
Claim 9
Dependent Claim
27 words
A magnetic recording medium according to claim 5, having an atomic ratio of oxygen atom to silicon atom in the protective layer of from 0.7:1 to 1.3:1.
Claim 10
Dependent Claim
24 words
A magnetic recording medium according to claim 1, which further comprises a second protective layer of a lubricant formed on said first protective layer.
Claim 11
Dependent Claim
39 words
A magnetic recording medium according to claim 8, wherein the oxygen content within a 20 Å thickness at the surface of the first protective layer is from 5 to 70% by weight of the organic polymer in said thickness.
Claim 12
Dependent Claim
24 words
A magnetic recording medium according to claim 9, wherein the oxygen content in the whole protective layer is from 5 to 50% by weight.
Claim 13
Dependent Claim
17 words
A magnetic recording medium according to claim 8, wherein said organic polymeric material further comprises silicon atoms.
Claim 14
Dependent Claim
17 words
A magnetic recording medium according to claim 8, wherein said organic polymeric material further comprises metal atoms.
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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) | 1991-04-12 | 1991-10-12 | 1992-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-12 | 1995-10-12 | 1996-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-12 | 1999-10-12 | 2000-04-12 | $7700.00 | Window Closed / Lapsed |