US4560616A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium having binder cured by electron beam radiation
Assignee: Fujifilm Holdings Corp
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Filing: 1983-08-09
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Granted: 1985-12-24
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Expires: 2003-08-09
Abstract
Abstract A magnetic recording medium comprising a support having coated thereon a magnetic layer is disclosed. The magnetic layer is comprised of a binder composition having ferromagnetic particles dispersed therein. The binder composition is cured by an electron beam and comprises a copolymer, a urethane resin and a compound having two or more acryloyl groups or methacryloyl groups. The copolymer may be a vinyl chloride-vinyl acetate-vinyl alcohol copolymer having a vinyl alcohol content of 1 to 15 wt % or a vinyl chloride-vinyl acetate-maleic acid copolymer having a maleic acid content of 1 to 10 wt %. The recording medium has excellent electromagnetic properties and the magnetic layer has excellent dynamic properties.
Inventors
- 👤 Tsutomu Okita
- 👤 Kyoichi Naruo
- 👤 Hiroshi Hashimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:10
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
151 words
A magnetic recording medium comprising a support having coated thereon a magnetic layer containing ferromagnetic particles dispersed in a binder, said binder comprising a vinyl chloride-vinyl acetate type copolymer selected from the group consisting of vinyl chloride-vinyl acetate-vinyl alcohol copolymers having a vinyl alcohol content of 1 to 15 wt % and vinyl chloride-vinyl acetate-maleic acid copolymers having a maleic acid content of 1 to 10 wt %; a urethane resin; and a compound having two or more acryloyl groups or methacryloyl group, wherein the copolymer and the urethane resin are each present in an amount in the range of 20 to 80 parts by weight and the compound is present in an amount in the range of 50 to 400 parts by weight based on 100 parts by weight of the mixture of the copolymer and the urethane resin, further wherein the binder composition is cured by electron beam radiation.
Claim 2
Dependent Claim
151 words
A magnetic recording medium comprising a support having coated thereon a magnetic layer containing ferromagnetic particles dispersed in a binder, said binder comprising a vinyl chloride-vinyl acetate type copolymer selected from the group consisting of vinyl chloride-vinyl acetate-vinyl alcohol copolymers having a vinyl alcohol content of 1 to 15 wt % and vinyl chloride-vinyl acetate-maleic acid copolymers having a maleic acid content of 1 to 10 wt %; a urethane resin; and a compound having two or more acryloyl groups or methacryloyl group, wherein the copolymer and the urethane resin are each present in an amount in the range of 20 to 80 parts by weight and the compound is present in an amount in the range of 50 to 400 parts by weight based on 100 parts by weight of the mixture of the copolymer and the urethane resin, further wherein the binder composition is cured by electron beam radiation.
Claim 3
Dependent Claim
33 words
A magnetic recording medium as claimed in claim 1, wherein the copolymer is the vinyl chloride-vinyl acetate-vinyl alcohol copolymer having a vinyl alcohol content in the range of 5 to 15 wt %.
Claim 4
Dependent Claim
33 words
A magnetic recording medium as claimed in claim 1, wherein the copolymer is the vinyl chloride-vinyl acetate-maleic acid copolymer having a maleic acid content in the range of 2 to 8 wt %.
Claim 5
Dependent Claim
24 words
A magnetic recording medium as claimed in claim 1, wherein the urethane resin has a molecular weight in the range of 5,000 to 100,000.
Claim 6
Dependent Claim
24 words
A magnetic recording medium as claimed in claim 1, wherein the urethane resin has a molecular weight in the range of 10,000 to 50,000.
Claim 7
Dependent Claim
23 words
A magnetic recording medium as claimed in claim 1, wherein the compound has a molecular weight in the range of 1,000 to 20,000.
Claim 8
Dependent Claim
31 words
A magnetic recording medium as claimed in claim 1, wherein the mixing weight ratio of the copolymer to the urethane, resin is in the range of 20 to 90:80 to 10.
Claim 9
Dependent Claim
31 words
A magnetic recording medium as claimed in claim 1, wherein the mixing weight ratio of the copolymer to the urethane resin is in the range of 40 to 80:60 to 20.
Claim 10
Dependent Claim
89 words
A magnetic recording medium as claimed in claim 1, wherein the ferromagnetic particles have an acicular ratio of ferromagnetic iron oxide and chromium dioxide of about 2/1 to about 20/1 and the particles have an average length of 0.2 to 2.0 mu and further wherein the ferromagnetic alloy fine particles have a metal content of not less than 75 wt % wherein not less than 80 wt % of the metal content is a ferromagnetic metal, the particles having a longer diameter of not more than about 1.0 mμ.
Claim 11
Dependent Claim
28 words
A magnetic recording medium as claimed in claim 1, wherein the vinyl chloride-vinyl acetate type copolymer has a breaking strength of more than about 5 kg/mm 2 .
Claim 12
Dependent Claim
22 words
A magnetic recording medium as claimed in claim 10, wherein the copolymer has an average molecular weight of more than about 15,000.
Claim 13
Dependent Claim
16 words
A magnetic recording medium as claimed in claim 1, wherein said compound is a cross-linking agent.
Claim 14
Dependent Claim
29 words
A magnetic recording medium as claimed in claim 9, wherein the ferromagnetic particles have an acicular ratio of ferromagnetic iron oxide and chromium dioxide of not less than 5/1.
Claim 15
Dependent Claim
43 words
A magnetic recording medium as claimed in claim 1, wherein the compound is present in an amount in the range of 80 to 250 parts by weight based on 100 parts by weight of the mixture of the copolymer and the urethane resin.
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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) | 1988-12-23 | 1989-06-24 | 1989-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-23 | 1993-06-24 | 1993-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-23 | 1997-06-24 | 1997-12-24 | $7700.00 | Window Closed / Lapsed |