US4731292A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Konica Minolta Inc
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Filing: 1986-11-14
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Granted: 1988-03-15
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Expires: 2006-11-14
Abstract
Abstract A magnetic recording medium is disclosed which comprises a support, and a magnetic layer comprising a specific binder resin, a fatty acid or a fatty acid ester and a magnetic particle. The binder resin comprises a monomer unit of vinyl chloride, a monomer unit having an alkalin metal salt of sulfonic acid or an alkaline salt of phosphoric acid and a monomer unit having an epoxy group. The magnetic recording medium is improved in a dispersibility of magnetic particles, a durability for still picture reproduction, a stability in running and in a S/N ratio of luminance.
Inventors
- 👤 Kunitsuna Sasaki
- 👤 Yoshitaka Yasufuku
- 👤 Toshiaki Shibue
- 👤 Kazumasa Matsumoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 19:28
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7023; G11B5/71; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31609; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
105 words
A magnetic recording medium comprising a support and, provided thereon, a magnetic layer comprising (a) copolymer resin comprising a monomer unit of vinyl chloride, a first monomer unit having an alkali metal salt of sulfonic acid or an alkali metal salt of phosphoric acid, a second monomer unit having an epoxy group, and a third monomer unit having a hydroxy group; (b) a fatty acid or a fatty acid ester; (c) magnetic particles; and (d) a polyurethane resin; said polymer is present in the ratio of from 90 to 10 parts by weight of said copolymer to 100 parts of said copolymer plus said polyurethane.
Claim 2
Dependent Claim
105 words
A magnetic recording medium comprising a support and, provided thereon, a magnetic layer comprising (a) copolymer resin comprising a monomer unit of vinyl chloride, a first monomer unit having an alkali metal salt of sulfonic acid or an alkali metal salt of phosphoric acid, a second monomer unit having an epoxy group, and a third monomer unit having a hydroxy group; (b) a fatty acid or a fatty acid ester; (c) magnetic particles; and (d) a polyurethane resin; said polymer is present in the ratio of from 90 to 10 parts by weight of said copolymer to 100 parts of said copolymer plus said polyurethane.
Claim 3
Dependent Claim
49 words
The medium of claim 1 wherein (b) is present in an amount of 0.5 to 20% by weight based on said magnetic particles, said first monomer unit being present in an amount of from 0.1 to 4.0% by weight based on the total monomer units of said copolymer resin.
Claim 4
Dependent Claim
50 words
The magnetic recording medium of claim 1, wherein the total content of said monomer unit having an alkali metal salt of sulfonic acid or an alkali metal salt of phosphoric acid is in the range of from 0.1% to 4% by weight of total monomer units of said polymer resin.
Claim 5
Dependent Claim
24 words
The medium of claim 2 wherein said (b) is present in an amount of 1.0 to 10% by weight based on said magnetic particles.
Claim 6
Dependent Claim
27 words
The magnetic recording medium of claim 1, wherein a weight average molecular weight Mw of said polyurethane resin is in the range of from 20,000 to 60,000.
Claim 7
Dependent Claim
35 words
The magnetic recording medium of claim 1. wherein the total content of said fatty acid or said fatty acid ester is in the range of from 0.5% to 20% by weight of said magnetic particle.
Claim 8
Dependent Claim
22 words
The magnetic recording medium of claim 1, wherein said magnetic layer contains both of said fatty acid and said fatty acid ester.
Claim 9
Dependent Claim
25 words
The magnetic recording medium of claim 1, wherein an amount by weight of said fatty acid is more than that of said fatty acid ester.
Claim 10
Dependent Claim
14 words
The magnetic recording medium of claim 1, wherein magnetic layer contains a phosphoric ester.
Claim 11
Dependent Claim
19 words
The magnetic recording medium of claim 1, wherein a coefficient of dynamical friction μk is not more than 0.3.
Claim 12
Dependent Claim
22 words
The medium of claim 2 wherein said magnetic layer was a coefficient of dynamic friction of less than 0.30 at 25° C.
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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) | 1991-03-15 | 1991-09-14 | 1992-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-15 | 1995-09-14 | 1996-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-15 | 1999-09-14 | 2000-03-15 | $7700.00 | Window Closed / Lapsed |