Patent US4107385A successfully refreshed from Google Patents.
US4107385A
Expired / Lapsed
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Magnetic recording medium
Assignee: Sony Corp
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Filing: 1975-05-21
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Granted: 1978-08-15
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Expires: 1995-05-21
Abstract
Abstract A magnetic recording medium comprising a base, for example, of a non-magnetic plastic resin, and a magnetic layer coated on the base and composed of a binder with a magnetic powder dispersed therein, is provided with a friction-reducing additive in the magnetic layer constituted by a boron compound obtained by the esterification of boric acid with a polyhydric alcohol having vicinal hydroxyl groups, such as, glycerin. The amount of such boron compound is from 1 to 15, and preferably, from 4 to 10 parts by weight for each 100 parts by weight of the binder. The preferred boron compounds are those including mono- or di-esters of a fatty acid with or without ethylene oxide.
Inventors
- 👤 Shigetaka Higuchi
- 👤 Masaatsu Iwasaki
- 👤 Shigeo Kimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:50
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/71; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31507; Y10T428/31511; Y10T428/31551; Y10T428/31565; Y10T428/31573; Y10T428/31587; Y10T428/31591; Y10T428/31609
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
139 words
A magnetic recording medium comprising a base, and a magnetic layer coated on the base and consisting essentially of a binder and a magnetic powder and, in admixture therewith, for each 100 parts by weight of said binder, from 1 to 15 parts by weight of a friction-reducing additive selected from the boron compounds having any one of the following structural formulas: ##STR10## in which B.sup.δ- represents a boron atom with a negative electric charge which has a low bonding force, H.sup.δ+ represents a hydrogen atom with a positive electric charge which also has a low bonding force, R represents an alkyl group containing from 7 to 21 carbon atoms, each of l and m is a numerical value from 1 to 20 and the sum of the numerical values of l and m is no greater than 24.
Claim 2
Dependent Claim
139 words
A magnetic recording medium comprising a base, and a magnetic layer coated on the base and consisting essentially of a binder and a magnetic powder and, in admixture therewith, for each 100 parts by weight of said binder, from 1 to 15 parts by weight of a friction-reducing additive selected from the boron compounds having any one of the following structural formulas: ##STR10## in which B.sup.δ- represents a boron atom with a negative electric charge which has a low bonding force, H.sup.δ+ represents a hydrogen atom with a positive electric charge which also has a low bonding force, R represents an alkyl group containing from 7 to 21 carbon atoms, each of l and m is a numerical value from 1 to 20 and the sum of the numerical values of l and m is no greater than 24.
Claim 3
Dependent Claim
19 words
A magnetic recording medium as in claim 1, in which said magnetic powder is γ-Fe 2 O 3 .
Claim 4
Dependent Claim
20 words
A magnetic recording medium as in claim 1, in which said magnetic powder is Co-doped γ-Fe 2 O 3 .
Claim 5
Dependent Claim
17 words
A magnetic recording medium as in claim 1, in which said magnetic powder is CrO 2 .
Claim 6
Dependent Claim
26 words
A magnetic recording medium as in claim 1, in which said magnetic powder is a mixture of Co-doped Fe 3 O 4 and CrO 2 .
Claim 7
Dependent Claim
32 words
A magnetic recording medium as in claim 1, in which said base is of a plastic resin selected from the group consisting of polyethylene terephthalate, cellulose acetate or triacetate, polypropylene and polycarbonate.
Claim 8
Dependent Claim
27 words
A magnetic recording medium as in claim 1, in which said binder is selected from the group consisting of vinylchloride-vinylacetate copolymer, acrylic, phenol, epoxy and polyurethane resins.
Claim 9
Dependent Claim
17 words
A magnetic recording medium as in claim 1, in which said boron compound is glycerol borate di-oleate.
Claim 10
Dependent Claim
18 words
A magnetic recording medium as in claim 1, in which said boron compound is polyoxyethylene glycerol borate di-oleate.
Claim 11
Dependent Claim
32 words
A magnetic recording medium as in claim 1, in which there are from 4 to 10 parts by weight of said boron compound for each 100 parts by weight of said binder.
Claim 12
Dependent Claim
17 words
A magnetic recording medium as in claim 1, in which said boron compound is glycerol borate isostearate.
Claim 13
Dependent Claim
18 words
A magnetic recording medium as in claim 1, in which said boron compound is polyoxyethylene glycerol borate stearate.
Claim 14
Dependent Claim
68 words
A magnetic recording medium as in claim 1, in which said boron compound is selected from the group consisting of (γ-lauroylglyceryl-α,β-glyceryl-α',β '-) boronium hydride; (γ-palmitoylglyceryl-α,β-glyceryl-α',β'-) boronium hydride; (γ-stearoylglyceryl-α,β-glyceryl-α',β '-) boronium hydride; (γ-isostearoylglyceryl-α,β-glyceryl-α',β'-) boronium hydride; (γ-hydroxylstearoylglyceryl-α,β-glyceryl-α',β'-) boronium hydride; bis-(γ-oleoylglyceryl-α,β-) boronium hydride; bis (γ-stearoylglyceryl-α,β') boronium hydride; (γ-lauroylpolyoxyethyleneglyceryl-α,β,γ '-polyoxyethyleneglyceryl-α',β'-) boronium hydride; (γ-palmitoylpolyoxyethyleneglyceryl-α,β,γ'-polyoxyethyleneglyceryl-α',β'-) boronium hydride; (γ-stearoylpolyoxyethylene glyceryl-α,β,γ'-polyoxyethyleneglyceryl-α',β'-) boronium hydride; (γ-oleoylpolyoxyethyleneglyceryl-α,β,γ'-polyoxyethyleneglyceryl-α',β'-) boronium hydride; (γ-isostearoylpolyoxyethyleneglyceryl-α,β,γ'-polyoxyethyleneglyceryl-α',β'-) boronium hydride; bis-(γ-stearoylpolyoxyethyleneglyceryl-α,β-) boronium hydride; and bis-(γ-oleoylpolyoxyethyleneglyceryl-α,β-) boronium hydride.
References Cited (Backward Citations)
US3398011A
Cited
US3852314A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-08-14 | 1982-02-13 | 1982-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-08-14 | 1986-02-13 | 1986-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-08-14 | 1990-02-13 | 1990-08-15 | $7700.00 | Window Closed / Lapsed |