US4670340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium and method
Assignee: TDK Corp
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Filing: 1985-08-19
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Granted: 1987-06-02
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Expires: 2005-08-19
Abstract
Abstract The invention provides a method for manufacturing a magnetic recording tape which is free from the problems of the phenomenon of dropout as well as runout of the tape roll throughout the life of the tape. The inventive method comprises providing a coating layer on a surface of a film base of the tape having been provided with the magnetic coating layer on the other surface with a coating composition comprising a radiation-sensitive curable polymeric material, which is a thermoplastic resin modified to be radiation-sensitive with or without admixture of a thermoplastic elastomer, and a filler dispersed therein and, prior to winding of the tape into a roll, irradiating the coating layer with a high energy radiation of, preferably, electron beams whereby the coating composition is fully radiation-cured to form a backing layer of the tape.
Inventors
- 👤 Yukihiro Isobe
- 👤 Kazushi Tanaka
- 👤 Masaharu Nishimatsu
- 👤 Osamu Shinoura
- 👤 Yuichi Kubota
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:33
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/62; G11B5/73; G11B5/735; G11B5/7356; G11B5/7358; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/269
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
135 words
A magnetic recording medium which comprises (a) a film base, (b) a magnetic coating layer provided on a surface of the film base and (c) a backing layer provided on the other surface of the film base having a surface roughness from 0.1 to 0.6 μm, said backing layer comprising a matrix of resinous binder cured by the irradiation of a radiation-sensitive copolymeric material with high energy radiation and a filler dispersed in the matrix, the amount of filler being from 20 to 100 parts by weight when the filler is electroconductive and from 10 to 300 parts by weight when the filler is non-conductive, each per 100 parts by weight of said resinous binder said copolymeric material comprising a copolymer of vinyl chloride rendered sensitive to radiation-induced curing by copolymerization with an acrylic monomer.
Claim 2
Dependent Claim
135 words
A magnetic recording medium which comprises (a) a film base, (b) a magnetic coating layer provided on a surface of the film base and (c) a backing layer provided on the other surface of the film base having a surface roughness from 0.1 to 0.6 μm, said backing layer comprising a matrix of resinous binder cured by the irradiation of a radiation-sensitive copolymeric material with high energy radiation and a filler dispersed in the matrix, the amount of filler being from 20 to 100 parts by weight when the filler is electroconductive and from 10 to 300 parts by weight when the filler is non-conductive, each per 100 parts by weight of said resinous binder said copolymeric material comprising a copolymer of vinyl chloride rendered sensitive to radiation-induced curing by copolymerization with an acrylic monomer.
Claim 3
Independent Claim
185 words
A method for the preparation of a magnetic recording medium comprising a film base, a magnetic coating layer provided on a surface of the film base, and a backing layer provided on the other surface of the film base which comprises: coating the surface of the film base reverse to the surface on which the magnetic coating layer has been provided with a coating composition comprising a radiation-sensitive curable copolymeric material as the binder and a filler dispersed in the copolymeric material, the amount of filler being from 20 to 100 parts by weight when the filler is electroconductive and from 10 to 300 parts by weight when the filler is non-conductive, each per 100 parts by weight of said resinous binder; and irradiating the coating composition on the surface of the film base with high energy radiation so as to cure the coating composition into a backing layer having a surface roughness from 0.1 to 0.6 μm on the surface of the film base said copolymeric material comprising a copolymer of vinvl chloride rendered sensitive to radiation-induced curing by copolymerization with an acrylic monomer.
Claim 4
Independent Claim
185 words
A method for the preparation of a magnetic recording medium comprising a film base, a magnetic coating layer provided on a surface of the film base, and a backing layer provided on the other surface of the film base which comprises: coating the surface of the film base reverse to the surface on which the magnetic coating layer has been provided with a coating composition comprising a radiation-sensitive curable copolymeric material as the binder and a filler dispersed in the copolymeric material, the amount of filler being from 20 to 100 parts by weight when the filler is electroconductive and from 10 to 300 parts by weight when the filler is non-conductive, each per 100 parts by weight of said resinous binder; and irradiating the coating composition on the surface of the film base with high energy radiation so as to cure the coating composition into a backing layer having a surface roughness from 0.1 to 0.6 μm on the surface of the film base said copolymeric material comprising a copolymer of vinvl chloride rendered sensitive to radiation-induced curing by copolymerization with an acrylic monomer.
Claim 5
Dependent Claim
38 words
The method as claimed in claim 2 wherein the irradiation of the coating composition with a high energy radiation is carried out with electron beams accelerated at an accelerating voltage in the range from 100 to 750 kilovolts.
Claim 6
Dependent Claim
36 words
The method as claimed in claim 3 wherein the irradiation of the coating composition with a high energy radiation is carried out to give an absorbed radiation dose in the range from 0.5 to 20 megarads.
Claim 7
Dependent Claim
40 words
The method as claimed in claim 2 wherein the filler is a finely divided particulate material selected from the group consisting of carbon black, graphite powder, calcium carbonate, goethite, talc, kaolin, calcium sulfate, fluorocarbon resins, fluorinated graphite and molybdenum disulfide.
Claim 8
Dependent Claim
17 words
The method as claimed in claim 5 wherein the filler is carbon black or a graphite powder.
Claim 9
Dependent Claim
30 words
The method as claimed in claim 2 wherein the irradiation of the coating composition with the high energy radiation is carried out in an atmosphere with substantial absence of oxygen.
Claim 10
Dependent Claim
33 words
The method as claimed in claim 2 wherein the irradiation of the coating composition with a high energy radiation is carried out prior to winding of the magnetic recording medium into a roll.
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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) | 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 |