US5008147A
Expired / Lapsed
US
⏱️ 0.0 years remaining
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 16:15
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.
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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) | 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 |