Patent US5353300A successfully refreshed from Google Patents.
Patent US5008147A successfully refreshed from Google Patents.
US5008147A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1988-07-08
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Granted: 1991-04-16
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Expires: 2008-07-08
Abstract
Abstract A magnetic recording medium comprising a nonmagnetic support having on one surface thereof a magnetic layer and on the opposite surface thereof a backing layer comprising nonmagnetic particles dispersed in a binder, wherein said binder of said backing layer comprises from about 20 to 90 wt % of polycarbonate polyurethane, and said backing layer comprises from about 40 to 200 parts by weight of said binder per 100 parts by weight of said nonmagnetic particles.
Inventors
- 👤 Katsumi Ryoke
- 👤 Masatoshi Takahashi
- 👤 Akihiro Hashimoto
- 👤 Kazuo Hasumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:48
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; Y10T428/25; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/30; Y10T428/31504; Y10T428/31551; Y10T428/31609
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
75 words
A magnetic recording medium comprising a nonmagnetic support having on one surface thereof a magnetic layer and on the opposite surface thereof a backing layer comprising nonmagnetic particles dispersed in a binder, wherein said binder of said backing layer comprises from about 20 to 90 wt % of polycarbonate polyurethane, and said backing layer comprises from about 40 to 200 parts by weight of said binder per 100 parts by weight of said nonmagnetic particles.
Claim 2
Dependent Claim
75 words
A magnetic recording medium comprising a nonmagnetic support having on one surface thereof a magnetic layer and on the opposite surface thereof a backing layer comprising nonmagnetic particles dispersed in a binder, wherein said binder of said backing layer comprises from about 20 to 90 wt % of polycarbonate polyurethane, and said backing layer comprises from about 40 to 200 parts by weight of said binder per 100 parts by weight of said nonmagnetic particles.
Claim 3
Dependent Claim
16 words
A magnetic recording medium as claimed in claim 1, wherein said nonmagnetic particles comprise carbon black.
Claim 4
Dependent Claim
62 words
A magnetic recording medium as claimed in claim 2, wherein said carbon black has an average particle size of from about 5 to 1,000 mμ, a nitrogen absorption specific surface area of from about 1 to 800 m 2 /g, a pH of from about 4 to 11, and a dibutylphthalate oil adsorption amount of from about 10 to 800 ml/100 g.
Claim 5
Dependent Claim
102 words
A magnetic recording medium as claimed in claim 1, wherein said polycarbonate polyurethane is a copolymer comprising (a) a polycarbonate polyol having a molecular weight of from about 300 to 200,000 and a hydroxyl value of from about 20 to 1,000, or a polycarbonate polyester polyol having a molecular weight of from about 400 to 200,000 and a hydroxyl value of from about 500 to 1,000; and (b) a polyisocyanate selected from the group consisting of hexamethylene diisocyanate, tolydine diisocyanate, isophorone diisocyanate, xylylene diisocyanate, cyclohexane diisocyanate, toluidine diisocyanate, 2,4 tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate and 1,5-naphthylene diisocyanate.
Claim 6
Dependent Claim
56 words
A magnetic recording medium as claimed in claim 1, wherein said polycarbonate polyurethane is substituted with at least one substituent selected from the group consisting of --SO 3 M, --COOM, --NH 2 , --SH, --OH, a phosphoric acid group and a phosphoric acid ester group, wherein M represents a hydrogen atom or an alkali metal atom.
Claim 7
Dependent Claim
49 words
A magnetic recording medium as claimed in claim 1, wherein said binder further comprises at least one resin selected from the group consisting of a phenoxy resin, an epoxy resin, a nitrocellulose, a vinyl chloride polymer, a vinyl chloride copolymer, a vinylidene chloride polymer, and a vinylidene chloride copolymer.
Claim 8
Dependent Claim
23 words
A magnetic recording medium as claimed in claim 1, wherein said backing layer has a thickness of from about 0.8 to 3.0 μm.
Claim 9
Dependent Claim
45 words
A magnetic recording medium as claimed in claim 1, wherein said binder of said backing layer comprises (1) said polycarbonate polyurethane, (2) at least one of a phenoxy resin, a polyvinyl chloride and a copolymer of vinyl chloride and vinyl acetate, and (3) a polyisocyanate.
Claim 10
Dependent Claim
31 words
A magnetic recording medium as claimed in claim 1, wherein said binder of said backing layer comprises (1) said polycarbonate polyurethane, (2) at least one phenoxy resin, and (3) a polyisocyanate.
Claim 11
Dependent Claim
24 words
A magnetic recording medium as claimed in claim 1, wherein the binder of the magnetic layer further comprises a polyurethane other than polycarbonate polyurethane.
References Cited (Backward Citations)
US4132827A
Cited
US4328935A
Cited
US4562117A
Cited
US4745017A
Cited
US4761338A
Cited
US4612244A
Cited
US4629646A
Cited
US4726992A
Cited
US4786557A
Cited
US4812358A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-15 | 1994-10-15 | 1995-04-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-15 | 1998-10-15 | 1999-04-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-15 | 2002-10-15 | 2003-04-16 | $7700.00 | Window Closed / Lapsed |