US4169912A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Iron oxide magnetic pigments for the production of magnetic coatings
Assignee: Dynamit Nobel AG
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Filing: 1977-11-03
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Granted: 1979-10-02
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Expires: 1997-11-03
Abstract
Abstract An iron oxide pigment having a coating of a silane of the formula R.sub.n Si(OR').sub.4-n wherein R is an, in some cases, branched or oxygen-bridge-containing alkyl or alkenyl moiety of 1 to 18 carbon atoms, or an aryl moiety, R' is an, in some cases, branched and, in some cases, oxygen-bridge-containing alkyl moiety of 1 to 8, N=1 to 3, Or a hydrolysis product thereof; a magnetic tape containing such coated iron oxide pigment and a process for coating such iron oxide pigment. There is particularly disclosed the treatment of iron oxide magnetic pigments to thereby improve their wear resistance and dispersibility in organic mediums.
Inventors
- 👤 Eduard Schonafinger
- 👤 Paul Deigner
- 👤 Manfred Ohlinger
- 👤 Helmut Jakusch
- 👤 Jurgen Amort
- 👤 Heinz Nestler
- 👤 Claus-Dietrich Seiler
- 👤 Otto Ambros
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:40
CPC Classifications
C; C09; C09C; C09C3/00; C09C3/12; C09C1/00; C09C1/22; C09C1/24; G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/71; C01; C01P; C01P2004/00; C01P2004/10; C01P2004/80; C01P2006/00; C01P2006/22; C01P2006/42; C01P2006/90; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/24372; Y10T428/2438; Y10T428/24388; Y10T428/24413; Y10T428/24421; Y10T428/26; Y10T428/266; Y10T428/31504; Y10T428/31652; Y10T428/31663
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
127 words
In a magnetic tape comprising a non-magnetic or non-magnetizable substrate and an adhering iron oxide pigment, the improvement wherein said iron oxide pigment is one which has been pretreated before dispersion thereof in a binding agent with an acid or alkaline solution of a silane of the formula R.sub.n Si(OR').sub.4-n wherein R is a straight or branched alkyl group having 1 to 18 carbon atoms or a straight or branched alkenyl group of 2 to 18 carbon atoms which alkyl or alkenyl group can contain an oxygen atom in the chain or an aryl group R' is a straight or branched chain C 1 -C 18 alkyl group which can contain an oxygen atom in the chain n=1 to 3 or its hydrolysis product and thereafter dried.
Claim 2
Dependent Claim
127 words
In a magnetic tape comprising a non-magnetic or non-magnetizable substrate and an adhering iron oxide pigment, the improvement wherein said iron oxide pigment is one which has been pretreated before dispersion thereof in a binding agent with an acid or alkaline solution of a silane of the formula R.sub.n Si(OR').sub.4-n wherein R is a straight or branched alkyl group having 1 to 18 carbon atoms or a straight or branched alkenyl group of 2 to 18 carbon atoms which alkyl or alkenyl group can contain an oxygen atom in the chain or an aryl group R' is a straight or branched chain C 1 -C 18 alkyl group which can contain an oxygen atom in the chain n=1 to 3 or its hydrolysis product and thereafter dried.
Claim 3
Dependent Claim
12 words
A magnetic tape according to claim 1 wherein said silane is glycidyloxypropyltrimethoxysilane.
Claim 4
Dependent Claim
12 words
A magnetic tape according to claim 1 wherein said silane is isobutyltrimethoxysilane.
Claim 5
Dependent Claim
31 words
A magnetic tape according to claim 1 wherein said magnetic tape comprises 3 to 5 parts by weight of said pretreated iron oxide pigment per part by weight of said binder.
Claim 6
Dependent Claim
31 words
A magnetic tape according to claim 1 wherein said magnetic tape comprises 2 to 10 parts by weight of said pretreated iron oxide pigment per part by weight of said binder.
Claim 7
Dependent Claim
73 words
A magnetic tape according to claim 5 containing a finder said binder having a vinyl chloride-vinyl acetate copolymer, a hydrolysis product thereof having 5 to 20 weight percent vinyl alcohol units, a copolymer of vinyl chloride with a low ester of maleic or fumaric acid, a polyvinylformal, a copolyamide, a mixture of an elastomer of isocyanate-free polyester urethane with vinyl chloride-vinyl acetate copolymer, a vinylidic chloride-acrylonitrile copolymer or polyester or a phenoxy resin.
Claim 8
Dependent Claim
32 words
A magnetic tape according to claim 5 wherein said substrate is an isocyanate-free polyester urethane with a vinyl chloride-vinyl acetate copolymer, a vinylidene chloride-acrylonitrile copolymer or a polyester of a phenoxy resin.
Claim 9
Dependent Claim
18 words
A magnetic tape according to claim 5 wherein said substrate has a thickness of 5 to 50 μm.
Claim 10
Dependent Claim
18 words
A magnetic tape according to claim 8 wherein said substrate has a thickness of 10 to 35 μm.
References Cited (Backward Citations)
GB1147518A
Cited
US3996407A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-10-01 | 1983-04-02 | 1983-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-10-01 | 1987-04-02 | 1987-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-10-01 | 1991-04-02 | 1991-10-02 | $7700.00 | Window Closed / Lapsed |