Patent US4786557A successfully refreshed from Google Patents.
US4786557A
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Magnetic recording medium of continuous form
Assignee: Fujifilm Holdings Corp
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Filing: 1987-04-20
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Granted: 1988-11-22
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Expires: 2007-04-20
Abstract
Abstract An improvement of a magnetic recording medium in the continuous form comprising a nonmagnetic support, a magnetic recording layer provided on one surface of the support, and a back layer provided on the other surface of the support comprising a binder and nonmagnetic particles dispersed therein. The improvement resides in that the binder of the back layer mainly contains: a polyurethane resin containing a repeating unit having at least one polar group selected from the group consisting of --SO 3 M, --OSO 3 M, --COOM and --PO(PM') 2 , wherein M is hydrogen or an alkali metal atom, and M' is hydrogen, an alkali metal atom or a lower hydrocarbon group; and a vinyl chloride copolymer containing a repeating unit having at least one polar group selected from the group consisting of --SO 3 M, --OSO 3 M, --COOM and --PO(OM') 2 , wherein M and M' have the same meanings as defined above.
Inventors
- 👤 Yutaka Kakuishi
- 👤 Takahito Miyoshi
- 👤 Masatoshi Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:20
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/0804; C08G18/0819; C08L; C08L75/00; C08L75/04; G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7021; G11B5/7022; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31511; Y10T428/31529; Y10T428/31551; Y10T428/31609; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
185 words
In a magnetic recording medium in a continuous form comprising a nonmagnetic support, a magnetic recording layer provided on one surface of the support, and a back layer provided on the other surface of the support comprising a binder and nonmagnetic particles dispersed therein, the improvement wherein said binder contains as principal ingredients: a polyurethane resin containing a repeating unit having at least one polar group selected from the group consisting of --so 3 M, --OSO 3 M, --COOM and --PO(OM') 2 , wherein M is hydrogen or an alkali metal atom, and M' is hydrogen, an alkali metal atom or a lower hydrocarbon group, in an amount of 0.001-50 mol %; and a vinyl chloride copolymer containing a repeating unit having at least one polar group selected from the group consisting of --SO 3 M, --OSO 3 M, [--COOM] and --PO(OM') 2 , wherein M and M' have the same meanings as defined above, in an amount of 0.001-5.0 mol %; and the ratio between the vinyl chloride copolymer and the polyurethane resin being in the range of from 35:65 to 80:20, by weight.
Claim 2
Dependent Claim
185 words
In a magnetic recording medium in a continuous form comprising a nonmagnetic support, a magnetic recording layer provided on one surface of the support, and a back layer provided on the other surface of the support comprising a binder and nonmagnetic particles dispersed therein, the improvement wherein said binder contains as principal ingredients: a polyurethane resin containing a repeating unit having at least one polar group selected from the group consisting of --so 3 M, --OSO 3 M, --COOM and --PO(OM') 2 , wherein M is hydrogen or an alkali metal atom, and M' is hydrogen, an alkali metal atom or a lower hydrocarbon group, in an amount of 0.001-50 mol %; and a vinyl chloride copolymer containing a repeating unit having at least one polar group selected from the group consisting of --SO 3 M, --OSO 3 M, [--COOM] and --PO(OM') 2 , wherein M and M' have the same meanings as defined above, in an amount of 0.001-5.0 mol %; and the ratio between the vinyl chloride copolymer and the polyurethane resin being in the range of from 35:65 to 80:20, by weight.
Claim 3
Dependent Claim
35 words
The magnetic recording medium as claimed in claim 1, wherein the ratio between the vinyl chloride copolymer and the polyurethane resin in said binder is in the range of from 40:60 to 70:30, by weight.
Claim 4
Dependent Claim
27 words
The magnetic recording medium as claimed in claim 1, wherein said binder is a cured mixture of the polyurethane resin, vinyl chloride copolymer and a polyisocyanate compound.
Claim 5
Dependent Claim
17 words
The magnetic recording medium as claimed in claim 1, wherein said back layer further contains a lubricant.
Claim 6
Dependent Claim
23 words
The magnetic recording medium as claimed in claim 1, wherein said vinyl chloride copolymer further contains a repeating unit having an epoxy group.
Claim 7
Dependent Claim
30 words
The magnetic recording medium as claimed in claim 1, wherein said vinyl chloride copolymer further contains a repeating unit having an epoxy group in an amount of 1-30 mol %.
Claim 8
Dependent Claim
40 words
The magnetic recording medium as claimed in claim 1, wherein said vinyl chloride copolymer further contains a repeating unit having an epoxy group in an amount of 0.01-0.5 mol based on 1 mol of a vinyl chloride repeating unit thereof.
References Cited (Backward Citations)
US4407901A
Cited
US4521486A
Cited
US4612244A
Cited
US4637959A
Cited
US4634633A
Cited
US4594124A
Cited
US4643934A
Cited
US4659626A
Cited
US4615949A
Cited
US4600521A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |