US3874890A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nacreous pigments and process for the production thereof
Assignee: Merck Patent GmbH
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Filing: 1973-08-21
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Granted: 1975-04-01
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Expires: 1993-08-21
Abstract
Abstract Golden colored nacreous pigments are produced from mica flakes coated with a layer of TiO2 and/or ZrO2 by a process comprising the precipitation of an iron hydroxide thereon from an aqueous iron salt solution by precipitating the iron hydroxide at a pH of above 5 from an aqeous ferrous salt solution and thereafter converting the thus-precipitated layer of iron hydroxide on the coated mica flakes to Fe2O3.
Inventors
- 👤 Horst Bernhard
- 👤 Reiner Esselborn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:04
CPC Classifications
C; C01; C01G; C01G49/00; C01G49/02; C01G49/06; C09; C09C; C09C1/00; C09C1/0015; B; B29; B29C; B29C48/00; B29C48/03; B29C48/04; C01P; C01P2004/00; C01P2004/60; C01P2004/61; C01P2006/00; C01P2006/60; C09C2200/00; C09C2200/10; C09C2200/102; C09C2200/30; C09C2200/301; C09C2220/00; C09C2220/10; C09C2220/106
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
101 words
A PROCESS FOR THE PRODUCTION OF GOLDEN NACREOUS PIGMENTS BY COATING MICA FLAKES WITH A LAYER OF FE2O3- CONTAINING TIO2, ZRO2, OR MIXTURES THEREOF, WHICH COMPRISES THE STEPS OF PRECIPITATING IRON HYDROXIDE SOLUTION ONTO MICA FLAKES COATED WITH TIO2, ZRO2, OR A MIXTURE THEREOF, BY ADDING AN AQUEOUS FE (II) SALT SOLUTION TO A SUSPENSION OF THE MICA FLAKES AT A CONSTANT TEMPERATURE AND A CONSTANT PH ABOVE 5 AND A RATE OF ADDITION NOT EXCEEDING THE RATE AT WHICH THE SALT IS CONVERTED TO HYDROXIDE AND ADSORBED ON THE MICA FLAKES, AND THEREAFTER OXIDIZING THE DEPOSITED IRON HYDROXIDE TO FE2O3.
Claim 2
Dependent Claim
101 words
A PROCESS FOR THE PRODUCTION OF GOLDEN NACREOUS PIGMENTS BY COATING MICA FLAKES WITH A LAYER OF FE2O3- CONTAINING TIO2, ZRO2, OR MIXTURES THEREOF, WHICH COMPRISES THE STEPS OF PRECIPITATING IRON HYDROXIDE SOLUTION ONTO MICA FLAKES COATED WITH TIO2, ZRO2, OR A MIXTURE THEREOF, BY ADDING AN AQUEOUS FE (II) SALT SOLUTION TO A SUSPENSION OF THE MICA FLAKES AT A CONSTANT TEMPERATURE AND A CONSTANT PH ABOVE 5 AND A RATE OF ADDITION NOT EXCEEDING THE RATE AT WHICH THE SALT IS CONVERTED TO HYDROXIDE AND ADSORBED ON THE MICA FLAKES, AND THEREAFTER OXIDIZING THE DEPOSITED IRON HYDROXIDE TO FE2O3.
Claim 3
Dependent Claim
15 words
A process according to claim 1, wherein the Fe (II) salt is iron (II) sulfate.
Claim 4
Dependent Claim
19 words
A process according to claim 1, wherein the precipitation is conducted at a pH of from 7.5 to 9.
Claim 5
Dependent Claim
19 words
A process according to claim 3, wherein the precipitation is conducted at a pH of from 8.0 to 8.5.
Claim 6
Dependent Claim
13 words
A process according to claim 1, wherein the oxidation is effected with air.
Claim 7
Dependent Claim
22 words
A process according to claim 5, wherein the oxidation is conducted concurrently with a drying step to dry the coated mica flakes.
Claim 8
Dependent Claim
27 words
A process according to claim 5, wherein the oxidation is conducted at least partially by introducing air into the solution from which the iron hydroxide is precipitated.
Claim 9
Dependent Claim
15 words
A process according to claim 1, wherein the mica flakes are coated with TiO2 hydrate.
Claim 10
Dependent Claim
41 words
A process according to claim 7, wherein the mica flakes have a diameter of about 5-250 microns and a thickness of about 0.1-5 microns and which are uniformly coated with a layer of about 100-300 mg. of TiO2/m2 of mica surface.
Claim 11
Dependent Claim
29 words
A process according to claim 1, wherein an amount of iron hydroxide is precipitated corresponding to up to 20 percent by weight calculated on the final pigment, of Fe2O3.
Claim 12
Dependent Claim
33 words
A process according to claim 10, wherein an amount of iron hydroxide corresponding to about 0.5-10 percent by weight of Fe2O3, calculated on the final pigment, is deposited on the coated mica flakes.
Claim 13
Dependent Claim
55 words
A golden nacreous pigment of improved brilliance and covering power, consisting essentially of translucent mica flakes coated with a pigment layer of TiO2, ZrO2, or mixtures thereof, having a substantially uniform layer of Fe2O3 of about 1-10 nm thickness on the surface of the pigment layer and produced according to the process of claim 1.
Claim 14
Dependent Claim
51 words
A pigment according to claim 12 wherein the mica flakes have a diameter of about 5-250 microns and a thickness of about 0.1-5 microns and which are uniformly coated with a layer of about 100-300 mg. of TiO2/m2 of mica surface, and a uniform coating of 0.5-10% by weight of Fe2O3.
References Cited (Backward Citations)
US3087828A
Cited
US3711308A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |