US4285825A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing magnetic coating material for magnetic recording media
Assignee: TDK Corp
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Filing: 1979-10-11
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Granted: 1981-08-25
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Expires: 1999-10-11
Abstract
Abstract A magnetic coating material for magnetic recording media is produced by dispersing a magnetic coating material containing from 0.1 to 2.0% of an abrasive and from 0.05 to 1.0% of a betaine type ampholytic antistatic agent, both on the basis of the amount of a magnetic powder, in a dispersion mill using steel balls. The abrasive has a hardness of not lower than 6 on Mohs' scale.
Inventors
- 👤 Yukihiro Isobe
- 👤 Masashi Hayama
- 👤 Kenji Hirabayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 02:50
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; G11B5/7085; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
84 words
A method of producing a magnetic coating material for magnetic recording media, which comprises the steps of charging a mixture of a magnetic powder and a binder composition containing from about 0.1 to about 2.0% of an abrasive and from about 0.05 to about 1.0% of a betaine type ampholytic antistatic agent, both on the basis of the amount of a magnetic powder, together with steel balls and dispersing said mixture; said abrasive having a hardness of not lower than 6 on Mohs' scale.
Claim 2
Independent Claim
84 words
A method of producing a magnetic coating material for magnetic recording media, which comprises the steps of charging a mixture of a magnetic powder and a binder composition containing from about 0.1 to about 2.0% of an abrasive and from about 0.05 to about 1.0% of a betaine type ampholytic antistatic agent, both on the basis of the amount of a magnetic powder, together with steel balls and dispersing said mixture; said abrasive having a hardness of not lower than 6 on Mohs' scale.
Claim 3
Independent Claim
85 words
A method for producing a degradation-resistant magnetic coating material for recording media comprising the steps of charging into a steel ball mill containing steel balls, a magnetic powder, a binder composition containing about 0.1% to about 2.0% of an abrasive having a Mohs' hardness of not less than 6 based on the weight of said megnetic power, and about 0.05 to about 1.0% of a betaine type ampholytic antistatic agent based on the weight of said magnetic powder, and dispersing said mixture in said mill.
Claim 4
Independent Claim
85 words
A method for producing a degradation-resistant magnetic coating material for recording media comprising the steps of charging into a steel ball mill containing steel balls, a magnetic powder, a binder composition containing about 0.1% to about 2.0% of an abrasive having a Mohs' hardness of not less than 6 based on the weight of said megnetic power, and about 0.05 to about 1.0% of a betaine type ampholytic antistatic agent based on the weight of said magnetic powder, and dispersing said mixture in said mill.
Claim 5
Independent Claim
38 words
The method of claims 1 or 2 in which said abrasive is selected from the group consisting of SiC, Al 2 O 3 , Cr 2 O 3 , SiO 2 , TiO 2 and CeO 2 .
References Cited (Backward Citations)
US3630910A
Cited
US3687725A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-24 | 1985-02-23 | 1985-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-24 | 1989-02-23 | 1989-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-24 | 1993-02-23 | 1993-08-25 | $7700.00 | Window Closed / Lapsed |