Patent US4334351A successfully refreshed from Google Patents.
Patent US4618535A successfully refreshed from Google Patents.
US4618535A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
•
Filing: 1984-08-20
•
Granted: 1986-10-21
•
Expires: 2004-08-20
Abstract
Abstract A magnetic recording medium comprising a plastic base film, a thin magnetic metal layer formed on one side of the base film and a backing layer formed on the other side of the base film, characterized in that the backing layer is composed essentially of a thermoset or radiation-cured resin and carbon black and inorganic compound powder uniformly dispersed in the resin, and has a surface roughness of from 0.05 to 0.4 μm, said carbon black having an average particle size of from 10 to 150 mμm as measured by an electron microscope, said inorganic compound powder having a Mohs hardness of at most 6 and a particle size of from 10 to 500 mμm, and the ratio of the carbon black to the inorganic compound powder being from 1:9 to 9:1.
Inventors
- 👤 Masaharu Nishimatsu
- 👤 Toshiaki Ide
- 👤 Hiroyuki Arioka
- 👤 Yuichi Kubota
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:43
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/735; G11B5/7356; G11B5/7358; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/252; Y10T428/256; Y10T428/257; Y10T428/258; Y10T428/30; Y10T428/31504; Y10T428/31551; Y10T428/31609; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
133 words
A magnetic recording medium comprising a plastic base film, a thin magnetic metal layer formed on one side of the base film and a backing layer formed on the other side of the base film, characterized in that the backing layer is composed essentially of a thermoset or radiation-cured resin and carbon black and inorganic compound powder uniformly dispersed in the resin, and has a surface roughness of from 0.05 to 0.4 μm, said carbon black having an average particle size of from 10 to 150 mμm as measured by an electron microscope, said inorganic compound powder having a Mohs hardness of at most 6 and a particle size of from 10 to 500 mμm, and the weight ratio of the carbon black to the inorganic compound powder being from 1:9 to 9:1.
Claim 2
Dependent Claim
133 words
A magnetic recording medium comprising a plastic base film, a thin magnetic metal layer formed on one side of the base film and a backing layer formed on the other side of the base film, characterized in that the backing layer is composed essentially of a thermoset or radiation-cured resin and carbon black and inorganic compound powder uniformly dispersed in the resin, and has a surface roughness of from 0.05 to 0.4 μm, said carbon black having an average particle size of from 10 to 150 mμm as measured by an electron microscope, said inorganic compound powder having a Mohs hardness of at most 6 and a particle size of from 10 to 500 mμm, and the weight ratio of the carbon black to the inorganic compound powder being from 1:9 to 9:1.
Claim 3
Dependent Claim
31 words
The magnetic recording medium according to claim 1, wherein the thermoset resin is made of a thermosetting binder comprising a vinyl chloride-vinyl acetate-vinyl alcohol copolymer, a polyurethane prepolymer and a polyisocyanate.
Claim 4
Dependent Claim
15 words
The magnetic recording medium according to claim 2, wherein the thermosetting binder further contains nitrocellulose.
Claim 5
Dependent Claim
26 words
The magnetic recording medium according to claim 1, wherein the radiation-cured resin is made of a radiation curable binder composed essentially of a radiation sensitive resin.
Claim 6
Dependent Claim
22 words
The magnetic recording medium according to claim 4, wherein the radiation sensitive resin has radiation curable acrylic, maleic or allyl-type double bonds.
Claim 7
Dependent Claim
32 words
The magnetic recording medium according to claim 1, wherein the inorganic compound powder is selected from the group consisting of CaCO 3 , kaolin, BaSO 4 and Fe 2 O 3 .
References Cited (Backward Citations)
US3993824A
Cited
US4328935A
Cited
US4474843A
Cited
US4414270A
Cited
US4443514A
Cited
US4486500A
Cited
US4419406A
Cited
US4451531A
Cited
US4452863A
Cited
US4547419A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-10-20 | 1990-04-21 | 1990-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-20 | 1994-04-21 | 1994-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-20 | 1998-04-21 | 1998-10-21 | $7700.00 | Window Closed / Lapsed |