Patent US4789583A successfully refreshed from Google Patents.
US4789583A
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Magnetic recording medium
Assignee: Konica Minolta Inc
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Filing: 1987-07-08
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Granted: 1988-12-06
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Expires: 2007-07-08
Abstract
Abstract A magnetic recording medium having a magnetic layer on one side of a support and a backcoat on the other side containing a non-magnetic powder and a binder resin is disclosed. The non-magnetic powder comprises particles having an average size greater than 0.5 μm and smaller than 2.0 μm and a maximum size of not more than 5 μm.
Inventors
- 👤 Shigeru Akutsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:03
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/735; G11B5/7356; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/24372; Y10T428/24413; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/258; Y10T428/259; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31551; Y10T428/31609; Y10T428/31942; Y10T428/31949
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
157 words
A magnetic recording medium comprising a support, a magnetic layer provided on one side of said support, and a backcoat provided on the other side of said support, wherein said backcoat comprises a binder resin and a non-magnetic powder, said binder resin being selected from the group consisting of polyurethane resin and nitrocellulose, said non-magnetic powder contained in an amount from 4-60% by weight of the total amount of components of said backcoat and having an average grain size of range of from 0.5 μm to 2 μm and a maximum grain size of not more than 5 μm and wherein the amount of non-magnetic powder having a grain size of more than 3 μm is less than 20% by weight of the total amount of said non-magnetic powder, said backcoat further containing an isocyanate as a hardener and said non-magnetic powder grains have an average center-line-average roughness (R a ) of 0.015 μm to 0.04 μm.
Claim 2
Dependent Claim
157 words
A magnetic recording medium comprising a support, a magnetic layer provided on one side of said support, and a backcoat provided on the other side of said support, wherein said backcoat comprises a binder resin and a non-magnetic powder, said binder resin being selected from the group consisting of polyurethane resin and nitrocellulose, said non-magnetic powder contained in an amount from 4-60% by weight of the total amount of components of said backcoat and having an average grain size of range of from 0.5 μm to 2 μm and a maximum grain size of not more than 5 μm and wherein the amount of non-magnetic powder having a grain size of more than 3 μm is less than 20% by weight of the total amount of said non-magnetic powder, said backcoat further containing an isocyanate as a hardener and said non-magnetic powder grains have an average center-line-average roughness (R a ) of 0.015 μm to 0.04 μm.
Claim 3
Dependent Claim
21 words
A magnetic recording medium according to claim 1, which has an intermediate layer provided in between said support and said backcoat.
Claim 4
Dependent Claim
24 words
A magnetic recording medium according to claim 1, wherein said backcoat has a thickness in the range of from 0.1 μm to 1.5 μm.
Claim 5
Dependent Claim
32 words
A magnetic recording medium according to claim 1, wherein said powder is in the range of from 15% to 40% by weight of the total amount of the components of said backcoat.
Claim 6
Dependent Claim
41 words
A magnetic recording medium according to claim 1, wherein said powder is selected from the group consisting of silicon oxide, titanium oxide, aluminum oxide, chromium oxide, silicon carbide, calcium carbide, boron nitride, zinc fluoride, molybdenum dioxide, calcium carbonate and barium sulfate.
Claim 7
Dependent Claim
21 words
A magnetic recording medium to claim 5, wherein said powder is either calcium carbonate or titanium oxide or a mixture thereof.
Claim 8
Dependent Claim
22 words
A magnetic recording medium according to claim 5, wherein said power is either calcium carbonate or titanium oxide or a mixture thereof.
Claim 9
Dependent Claim
22 words
A magnetic recording medium according to claim 5, wherein said powder is either calcium carbonate or titanium oxide or a mixture thereof.
Claim 10
Dependent Claim
16 words
A magnetic recording medium according to claim 1, wherein said backcoat further contains an antistatic agent.
Claim 11
Dependent Claim
16 words
A magnetic recording medium according to claim 9, wherein said antistatic agent is a carbon black.
Claim 12
Dependent Claim
20 words
A magnetic recording medium according to claim 1, wherein said backcoat contains both an aliphatic isocyanate and an aromatic isocyanate.
Claim 13
Dependent Claim
29 words
A magnetic recording medium according to claim 1, wherein said isocyanate is in the range of from 5% to 50% by weight of the binder resin in said backcoat.
Claim 14
Dependent Claim
26 words
A magnetic recording medium according to claim 12, wherein said isocyanate is in the range of from 5% to 25% by weight of said binder resin.
Claim 15
Dependent Claim
15 words
A magnetic recording medium according to claim 1, wherein said backcoat further contains a dispersant.
Claim 16
Dependent Claim
15 words
A magnetic recording medium according to claim 1, wherein said backcoat further contains a lubricant.
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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) | 1991-12-06 | 1992-06-06 | 1992-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-06 | 1996-06-06 | 1996-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-06 | 2000-06-06 | 2000-12-06 | $7700.00 | Window Closed / Lapsed |