US4867794A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing rutile-coated mica pigments
Assignee: Merck Patent GmbH
•
Filing: 1987-12-11
•
Granted: 1989-09-19
•
Expires: 2007-12-11
Abstract
Abstract In mica/titanium dioxide pigments reliable rutilization is obtained with small amounts of tin by precipitating tin dioxide directly on the mica and completing this precipitation before the precipitation of titanium dioxide is started.
Inventors
- 👤 Klaus Ambrosius
- 👤 August Knapp
- 👤 Helmut Plamper
- 👤 Reiner Esselborn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:54
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/0015; C09C1/0021; C01; C01P; C01P2002/00; C01P2002/30; C01P2004/00; C01P2004/80; C01P2004/82; C01P2004/84; C09C2200/00; C09C2200/10; C09C2200/102; C09C2220/00; C09C2220/10; C09C2220/106
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
53 words
A process for the preparation of metal oxide coated mica flake pearl luster pigments, comprising precipitating onto a mica flake in aqueous suspension a layer of tin dioxide and a layer of titanium dioxide, wherein the precipitation of the tin dioxide is substantially concluded before the precipitation of the titanium dioxide is begun.
Claim 2
Dependent Claim
53 words
A process for the preparation of metal oxide coated mica flake pearl luster pigments, comprising precipitating onto a mica flake in aqueous suspension a layer of tin dioxide and a layer of titanium dioxide, wherein the precipitation of the tin dioxide is substantially concluded before the precipitation of the titanium dioxide is begun.
Claim 3
Dependent Claim
37 words
A process according to claim 1, wherein the tin dioxide is precipitated from an aqueous solution of a divalent or tetravalent tin salt and the titanium dioxide is precipitated from an aqueous solution of TiCl 4 .
Claim 4
Dependent Claim
14 words
A process according to claim 2, wherein the tin salt is SnCl 4 .
Claim 5
Dependent Claim
16 words
A process according to claim 3, wherein the tin salt is SnCl 4 .5H 2 O.
Claim 6
Dependent Claim
35 words
A process according to claim 1, wherein the tin salt is used in such an amount that the tin content of the pigment, based on the mica used, is about 0.25 to 1.0% by weight.
Claim 7
Dependent Claim
20 words
A process according to claim 1, wherein the tin dioxide is precipitated at a pH of about 1.5 to 2.0.
Claim 8
Dependent Claim
20 words
A process according to claim 6, wherein the titanium dioxide is precipitated at a ph of about 1.5 to 2.0.
Claim 9
Dependent Claim
26 words
A process according to claim 1, wherein the precipitation of the metal oxides is carried out at a temperature of about 50° to about 100° C.
Claim 10
Dependent Claim
25 words
A process according to claim 1, wherein the pigment is calcined at about 850° C. for at least thirty minutes or under conditions equivalent thereto.
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) | 1992-09-18 | 1993-03-20 | 1993-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-18 | 1997-03-20 | 1997-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-18 | 2001-03-20 | 2001-09-19 | $7700.00 | Window Closed / Lapsed |