US5022923A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pearl luster pigments stable to glaze and enamel
Assignee: Merck Patent GmbH
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Filing: 1986-10-08
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Granted: 1991-06-11
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Expires: 2006-10-08
Abstract
Abstract Pearl luster pigments based on mica flakes coated with metal oxides are provided with a top coating of tin dioxide and/or cerium dioxide to improve their stability in glazes and enamels.
Inventors
- 👤 Axel Rau
- 👤 Klaus Ambrosius
- 👤 Klaus D. Franz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:42
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/36; C09C1/0009; C09C1/0015; C09C1/0021; C09C3/00; C09C3/06; C09C3/063; C01; C01P; C01P2004/00; C01P2004/20; C01P2004/60; C01P2004/61; C01P2004/80; C01P2004/82; C01P2004/84; C09C2200/00; C09C2200/10; C09C2200/102; C09C2200/40; C09C2200/401; C09C2220/00; C09C2220/10; C09C2220/103; C09C2220/106
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
66 words
A pearlescent pigment stable during preparation of glaze and enamel compositions containing the same, comprising mica flakes coated with at least one metal oxide layer and, in addition, a top layer, wherein the top layer is a mixture tin dioxide and cerium dioxide, in an amount of 10-30% by weight effective to stabilize the pigment to degradation from a coating of an enamel or a glaze.
Claim 2
Dependent Claim
66 words
A pearlescent pigment stable during preparation of glaze and enamel compositions containing the same, comprising mica flakes coated with at least one metal oxide layer and, in addition, a top layer, wherein the top layer is a mixture tin dioxide and cerium dioxide, in an amount of 10-30% by weight effective to stabilize the pigment to degradation from a coating of an enamel or a glaze.
Claim 3
Dependent Claim
42 words
A pearlescent pigment comprising mica flakes coated with at least one metal oxide layer and, in addition, a top layer of cerium dioxide, in an amount effective to stabilize the pigment to degradation from a coating of an enamel or a glaze.
Claim 4
Dependent Claim
42 words
A pearlescent pigment comprising mica flakes coated with at least one metal oxide layer and, in addition, a top layer of cerium dioxide, in an amount effective to stabilize the pigment to degradation from a coating of an enamel or a glaze.
Claim 5
Independent Claim
40 words
A method of increasing the stability in enamel and glaze compositions of pearlescent pigments based on mica flakes coated with at least one metal oxide, comprising providing the pigments with an additional top coating which consists essentially of cerium dioxide.
Claim 6
Independent Claim
40 words
A method of increasing the stability in enamel and glaze compositions of pearlescent pigments based on mica flakes coated with at least one metal oxide, comprising providing the pigments with an additional top coating which consists essentially of cerium dioxide.
Claim 7
Dependent Claim
20 words
A pigment of claim 2, wherein the weight of the top layer is 10-20% by weight of the total pigment.
Claim 8
Dependent Claim
20 words
A pigment of claim 2, wherein the weight of the top layer is 5-30% by weight of the total pigment.
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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) | 1994-06-10 | 1994-12-10 | 1995-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-10 | 1998-12-10 | 1999-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-10 | 2002-12-10 | 2003-06-11 | $7700.00 | Window Closed / Lapsed |