Patent US1879037A successfully refreshed from Google Patents.
US4656089A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Sony Corp
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Filing: 1985-10-08
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Granted: 1987-04-07
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Expires: 2005-10-08
Abstract
Abstract A magnetic recording medium comprising a non-magnetic base and a magnetic layer attached thereto consisting essentially of magnetic powders and a binder. Included within the binder are spherical small sized particles of a benzoguanamine-formaldehyde resin or a benzoguanamine-melamine-formaldehyde resin which serve to improve the running characteristics, reduce the friction coefficient, and improve the strength of the layer.
Inventors
- 👤 Yoshinobu Ninomiya
- 👤 Masakazu Muroyama
- 👤 Masayoshi Sugiyama
- 👤 Akira Hashimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 02:43
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/254; Y10T428/256; Y10T428/257; Y10T428/31504; Y10T428/31551; Y10T428/31609
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
55 words
A magnetic recording medium comprising a non-magnetic base and a magnetic layer containing magnetic powder and a binder attached to said base, said magnetic layer having dispersed therein spherical small sized particles of a benzoguanamine-formaldehyde resin or a benzoguanamine-melamine-formaldehyde resin, the particle size of said resin being in the range from 0.1 to 3 microns.
Claim 2
Dependent Claim
55 words
A magnetic recording medium comprising a non-magnetic base and a magnetic layer containing magnetic powder and a binder attached to said base, said magnetic layer having dispersed therein spherical small sized particles of a benzoguanamine-formaldehyde resin or a benzoguanamine-melamine-formaldehyde resin, the particle size of said resin being in the range from 0.1 to 3 microns.
Claim 3
Dependent Claim
25 words
A magnetic recording medium according to claim 1 in which said magnetic powder has a specific surface area of at least 30 m 2 /g.
Claim 4
Dependent Claim
85 words
A magnetic recording medium comprising a non-magnetic base and a magnetic layer containing magnetic powder attached to said base, said magnetic powder having a specific surface area of at least 30 m 2 /g, said magnetic layer having dispersed therein spherical particles of a benzoguanamine-formaldehyde resin or a benzoguanamine-melamine-formaldehyde resin, said resin having a particle size of from 0.1 to 3 microns, said particles being present in an amount of from 1 to 10 parts by weight for 100 parts by weight of magnetic powder.
Claim 5
Dependent Claim
85 words
A magnetic recording medium comprising a non-magnetic base and a magnetic layer containing magnetic powder attached to said base, said magnetic powder having a specific surface area of at least 30 m 2 /g, said magnetic layer having dispersed therein spherical particles of a benzoguanamine-formaldehyde resin or a benzoguanamine-melamine-formaldehyde resin, said resin having a particle size of from 0.1 to 3 microns, said particles being present in an amount of from 1 to 10 parts by weight for 100 parts by weight of magnetic powder.
Claim 6
Dependent Claim
31 words
A magnetic recording medium according to claim 1 wherein said particles are present in an amount of 1 to 10 parts by weight for 100 parts by weight of magnetic powder.
Claim 7
Dependent Claim
59 words
A magnetic recording medium according to claim 1 wherein said binder is a synthetic resin having at least one of the following hydrophilic polar groups attached thereto: --SO 3 M --OSO 3 M --COOM and ##STR6## where M is a hydrogen atom or an alkali metal, and M' is a hydrogen atom, an alkali metal or a hydrocarbon group.
Claim 8
Dependent Claim
26 words
A magnetic recording medium according to claim 5 in which said synthetic resin is a polyurethane resin, a polyester resin, or a vinyl chloride-vinyl acetate copolymer.
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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) | 1990-04-06 | 1990-10-06 | 1991-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-06 | 1994-10-06 | 1995-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-06 | 1998-10-06 | 1999-04-07 | $7700.00 | Window Closed / Lapsed |