US4744832A
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Iron oxide coated perlescent pigments
Assignee: Merck Patent GmbH
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Filing: 1986-08-07
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Granted: 1988-05-17
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Expires: 2006-08-07
Abstract
Abstract The application relates to a pearlescent pigments based on platelet-like substrates, such as mica, which are coated with metal oxides, the metal oxide layer containing titanium and also iron, wherein the pigment has a multi-layer structure in which a first layer of TiO 2 in the rutile form is followed by a layer of pseudobrookite and an iron oxide layer.
Inventors
- 👤 Klaus D. Franz
- 👤 Klaus Ambrosius
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:49
CPC Classifications
A; A61; A61Q; A61Q1/00; A61Q1/02; C; C09; C09C; C09C1/00; C09C1/28; A61K; A61K8/00; A61K8/18; A61K8/19; A61K8/29; C09C1/0015; A61K2800/00; A61K2800/40; A61K2800/41; A61K2800/412; A61K2800/42; A61K2800/43; A61K2800/436; A61K2800/60; A61K2800/61; A61K2800/62; A61K2800/63; A61K2800/65; A61K2800/651; C01; C01P; C01P2002/00; C01P2002/30; C01P2004/00; C01P2004/80; C01P2004/82; C01P2004/84; C09C2200/00; C09C2200/10; C09C2200/102; C09C2200/20; C09C2200/205; C09C2200/30; C09C2200/302; C09C2200/306; Y; Y10; Y10T; Y10T428/00; Y10T428/25; Y10T428/251
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
142 words
In a pearlescent pigment comprising a plateletlike substrate coated with metal oxides, the metal oxide layer containing titanium dioxide and iron oxide, the improvement wherein the pigment comprises a multi-layer structure in which superimposed on the substrate is a first layer of TiO 2 in the rutile form, formed from a precipitated layer of titanium dioxide or titanium dioxide hydrate, having a thickness of at least 40 nm, the latter being superimposed by a layer of pseudobrookite and the latter being superimposed by an iron oxide layer, formed by the precipitation of an iron oxide or hydroxide layer, having a thickness of at least 15 nm, wherein the TiO 2 concentration, relative to the total pigment, is about 20 to about 50% by weight, and the iron side concentration relative to the total pigment, is about 10 to about 50% by weight.
Claim 2
Dependent Claim
142 words
In a pearlescent pigment comprising a plateletlike substrate coated with metal oxides, the metal oxide layer containing titanium dioxide and iron oxide, the improvement wherein the pigment comprises a multi-layer structure in which superimposed on the substrate is a first layer of TiO 2 in the rutile form, formed from a precipitated layer of titanium dioxide or titanium dioxide hydrate, having a thickness of at least 40 nm, the latter being superimposed by a layer of pseudobrookite and the latter being superimposed by an iron oxide layer, formed by the precipitation of an iron oxide or hydroxide layer, having a thickness of at least 15 nm, wherein the TiO 2 concentration, relative to the total pigment, is about 20 to about 50% by weight, and the iron side concentration relative to the total pigment, is about 10 to about 50% by weight.
Claim 3
Dependent Claim
12 words
A pearlescent pigment according to claim 1, wherein the substrate is mica.
Claim 4
Dependent Claim
57 words
A pearlescent pigment according to claim 1, wherein dopants which are selected from compounds of aluminum(III), silicon(IV), zirconium(IV), chromium(III), boron(III) and phosphorous(V) are incorporated into at least one of the TiO 2 and Fe 2 O 3 layers, said copants being present in a total of not more than about 5% by weight based on the pigment.
Claim 5
Dependent Claim
112 words
In a process for preparing pearlescent pigments by coating platelet-like substrates with an iron- and titanium-containing metal oxide layer, the improvement comprising first precipitating a titanium dioxide or titanium dioxide hydrate layer having a thickness of at least 40 nm and a concentration relative to the total pigment of about 20-50% by weight, said layer being calcinable to form a rutile layer, and before or after calcination of resultant pigment, precipitating an iron oxide or hydroxide layer having a thickness of at least 15 nm, and a concentration relative to the total pigment of about 10-50% by weight on the titanium dioxide or the titanium dioxide hydrate layer, and calcining the pigment.
Claim 6
Dependent Claim
112 words
In a process for preparing pearlescent pigments by coating platelet-like substrates with an iron- and titanium-containing metal oxide layer, the improvement comprising first precipitating a titanium dioxide or titanium dioxide hydrate layer having a thickness of at least 40 nm and a concentration relative to the total pigment of about 20-50% by weight, said layer being calcinable to form a rutile layer, and before or after calcination of resultant pigment, precipitating an iron oxide or hydroxide layer having a thickness of at least 15 nm, and a concentration relative to the total pigment of about 10-50% by weight on the titanium dioxide or the titanium dioxide hydrate layer, and calcining the pigment.
Claim 7
Dependent Claim
38 words
A process according to claim 4, the step of precipitating said layer calcinable to rutile comprises precipitation of a TiO 2 layer, an SnO 2 intermediate layer and then an additional TiO 2 layer onto the platelet-like substrate.
Claim 8
Dependent Claim
16 words
A process according to claim 4, wherein the calcination occurs at about 700° to 950° C.
Claim 9
Dependent Claim
18 words
A process according to claim 4, wherein the TiO 2 layer is about 40 to about 200 nm.
Claim 10
Dependent Claim
19 words
A process according to claim 4, wherin the TiO 2 layer is about 40 to about 200 nm. .
Claim 11
Dependent Claim
20 words
A process according to claim 8, wherein the iron oxide layer has a thickness of about 20 to 40 nm.
Claim 12
Dependent Claim
22 words
A process according to claim 4, wherein the iron oxide is precipitated onto an uncalcined titanium dioxide or titanium dioxide hydrate layer.
Claim 13
Dependent Claim
22 words
A process according to claim 4, wherein the titanium dioxide or titanium dioxide hydrate layer has a thickness of about 40-150 nm.
Claim 14
Dependent Claim
29 words
A process according to claim 4, wherein the iron oxide is Fe 2 O 3 and the Fe 2 O 3 layer has a thickness of about 15-50 nm.
Claim 15
Dependent Claim
20 words
A process according to claim 12, wherein the Fe 2 O 3 layer has a thickness of about 20-40 nm.
Claim 16
Dependent Claim
21 words
A perlescent pigment according to claim 1, wherein the iron oxide concentration, relative to the total pigment, is 15-50% by weight.
Claim 17
Dependent Claim
20 words
A process according to claim 4, wherein the iron oxide concentration, relative to the total pigment, is 10-50% by weight.
Claim 18
Dependent Claim
21 words
A process according to claim 4, wherein the iron oxide concentration, relative to the total pigment, is about 15-50% 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) | 1991-05-17 | 1991-11-16 | 1992-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-17 | 1995-11-16 | 1996-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-17 | 1999-11-16 | 2000-05-17 | $7700.00 | Window Closed / Lapsed |