Patent EP0243171A1 successfully refreshed from Google Patents.
US4014710A
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US
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Magnetic pigments with improved orientability and a process for their production
Assignee: Toda Kogyo Corp
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Filing: 1974-07-18
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Granted: 1977-03-29
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Expires: 1994-07-18
Abstract
Abstract An acicular, magnetic iron oxide pigment containing about 0.05 to 5% by weight of an organo silicon compound is produced by treating iron oxide hydroxide seeds either dry or in suspension with an organo silicon compound. Preferred organo silicon compounds comprise polymethylphenylsiloxane, polydimethylsiloxane and polydiphenylsiloxane. Trivalent metal ions may subsequently be deposited. The resulting pigments show only minimal losses of coercive force during processing into magnetic tapes.
Inventors
- 👤 Peter Woditsch
- 👤 Franz Hund
- 👤 Gunter Buxbaum
- 👤 Volker Hahnkamm
- 👤 Ingo Pflugmacher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:26
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70652; G11B5/70668; G11B5/70673; C; C01; C01G; C01G49/00; C01G49/02; C09; C09C; C09C1/00; C09C1/22; C09C1/24; G11B5/70657; G11B5/70663; C01P; C01P2002/00; C01P2002/50; C01P2002/80; C01P2002/82; C01P2004/00; C01P2004/10; C01P2006/00; C01P2006/42
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
58 words
In the production of an acicular, magnetic iron oxide pigment by forming acicular iron oxide hydroxide seeds, growing said seeds, dehydrating, reducing and reoxidizing, the improvement which comprises contacting said precursor pigment as α-FeOOH, β-FeOOH or γ-FeOOH before hydration either in dry form or in suspension with about 0.05 to 5% its weight of an organo silicon compound.
Claim 2
Dependent Claim
58 words
In the production of an acicular, magnetic iron oxide pigment by forming acicular iron oxide hydroxide seeds, growing said seeds, dehydrating, reducing and reoxidizing, the improvement which comprises contacting said precursor pigment as α-FeOOH, β-FeOOH or γ-FeOOH before hydration either in dry form or in suspension with about 0.05 to 5% its weight of an organo silicon compound.
Claim 3
Dependent Claim
17 words
The process of claim 1, wherein the organo silicon compound is a silicone resin or silicone oil.
Claim 4
Dependent Claim
26 words
The process of claim 1, wherein the organo silicon compound is at least one of a polydiorganosiloxane, an organohalogensilane, an organosilanol and an alkali metal organosiliconate.
Claim 5
Dependent Claim
23 words
The process of claim 3, wherein the organo silicon compound is at least one of a polymethylphenyl siloxane, a polydimethylsiloxane and a polydiphenylsiloxane.
Claim 6
Dependent Claim
28 words
The process of claim 1, wherein the acicular iron oxide hydroxide is treated with the organo silicion compound in suspension at a pH of about 2 to 9.
Claim 7
Dependent Claim
48 words
The process of claim 1, wherein following the addition of the organo silicion compound about 0.05 to 2% by weight of a trivalent metal ion based on the weight of iron oxide hydroxide is precipitated onto the iron oxide hydroxide at a pH of about 5 to 7.
Claim 8
Dependent Claim
28 words
The process of claim 6, wherein the trivalent metal ion precipitated is at least one of iron, chromium, manganese, aluminum, gallium, indium, lanthanum, cerium and the rare earths.
Claim 9
Dependent Claim
26 words
An acicular, magnetic iron oxide pigment containing about 0.05 to 5% by weight of an organo silicon compound and produced by the process of claim 1.
Claim 10
Dependent Claim
64 words
An acicular, magnetic iron oxide pigment according to claim 8, wherein the organo silicon compound is at least one polydiorganosiloxane, organohalogensilane or alkali metal organosiliconate which, in the IR spectrum, shows at least one characteristic band in one of the following wave-length ranges: 1240 to 1280 cm - 1 , 1430 to 1470 cm - 1 , 1000 to 1150 cm - 1 .
Claim 11
Dependent Claim
58 words
An acicular, magnetic iron oxide pigment according to claim 9, containing up to about 10% by weight of at least one of Co, Zn, Cd, Mn and Ni and about 0.05 to 2% by weight of at least one trivalent metal ion selected from the group consisting of Cr, Al, Ga, In, La, Ce and the rare earths.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-28 | 1980-09-27 | 1981-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-28 | 1984-09-27 | 1985-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-28 | 1988-09-27 | 1989-03-29 | $7700.00 | Window Closed / Lapsed |