US3916038A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of producing moldable magnetic powder of the ferrite type
Assignee: Lion Fat and Oil Co Ltd
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Filing: 1973-02-23
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Granted: 1975-10-28
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Expires: 1993-02-23
Abstract
Abstract A process for producing a moldable magnetic particulate composition comprising core particles of a ferrite compound coated with a thermoplastic polymer comprising suspending the ferrite particles in an aqueous medium containing an ethylenically unsaturated monomer of a thermoplastic polymer in the presence of a bisulfite ion releasing compound and initiating polymerization of the monomer to cause the resulting polymer to be deposited in situ on the ferrite particles.
Inventors
- 👤 Tadashi Yamaguchi
- 👤 Hiroshi Kojima
- 👤 Takayuki Ono
- 👤 Hiroshi Hoshi
- 👤 Michio Hirakwa
- 👤 Isao Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:31
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/10; H01F1/11; H01F1/113
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
96 words
A PROCESS FOR PRODUCING A MOLDABLE MAGNETIC PARTICULATE COMPOSITION COMPRISING FINELY DIVIDED DISCRETE CORE PARTICLES OF A FERRITE COMPOUND COATED WITH A THERMOPLASTIC POLYMER OF AT LEAST ONE ETHYLENICALLY UNSATURATED MONOMER, WHICH COMPRISES THE STEPS OF SUSPENDING SAID DISCRETE FERRITE PARTICLES IN AN AQUEOUS MEDIUM CONTAINING AT LEAST ONE ETHYLENICALLY UNSATURATED MONOMER OF A THERMOPLASTIC POLYMER INSOLUBLE IN SAID MEDIUM IN THE PRESENCE OF A COMPOUND RELEASING BISULFITE IONS IN SAID AQUEOUS MEDIUM AND INITIATING POLYMERIZATION OF SAID MONOMER TO CAUSE THE RESULTANT POLYMER TO BE DEPOSITED IN SITU AS AN INTIMATE COATING OF SAID PARTICLES.
Claim 2
Dependent Claim
96 words
A PROCESS FOR PRODUCING A MOLDABLE MAGNETIC PARTICULATE COMPOSITION COMPRISING FINELY DIVIDED DISCRETE CORE PARTICLES OF A FERRITE COMPOUND COATED WITH A THERMOPLASTIC POLYMER OF AT LEAST ONE ETHYLENICALLY UNSATURATED MONOMER, WHICH COMPRISES THE STEPS OF SUSPENDING SAID DISCRETE FERRITE PARTICLES IN AN AQUEOUS MEDIUM CONTAINING AT LEAST ONE ETHYLENICALLY UNSATURATED MONOMER OF A THERMOPLASTIC POLYMER INSOLUBLE IN SAID MEDIUM IN THE PRESENCE OF A COMPOUND RELEASING BISULFITE IONS IN SAID AQUEOUS MEDIUM AND INITIATING POLYMERIZATION OF SAID MONOMER TO CAUSE THE RESULTANT POLYMER TO BE DEPOSITED IN SITU AS AN INTIMATE COATING OF SAID PARTICLES.
Claim 3
Dependent Claim
14 words
The process of claim 1 wherein said medium is heated to promote said polymerization.
Claim 4
Dependent Claim
32 words
The process of claim 1 wherein the amount of said bisulfite ions calculated in terms of sulfur dioxide is about 0.01-500 parts per weight per 100 parts by weight of said monomer.
Claim 5
Dependent Claim
30 words
The process of claim 1 wherein said particles have a diameter of about 0.1 Mu to about 3 Mu and said coating constitutes about 1-20% by volume of said particles.
Claim 6
Dependent Claim
21 words
The process of claim 1 wherein said monomer and ferrite particles are present in a ratio of about 0.0002-2:1 by weight.
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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) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |