US4334933A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing stable inorganic pigment
Assignee: Toho Ganryo Kogyo Co Ltd
•
Filing: 1979-12-31
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Granted: 1982-06-15
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Expires: 1999-12-31
Abstract
Abstract A process for preparing a stable inorganic pigment coated with a fine amorphous silica which comprises forming a silica sol in an aqueous prepared slurry of an inorganic pigment by reacting an alkali silicate solution with one or more acid gases so that a fine silica sol covers the surfaces of the particles of the inorganic pigment.
Inventors
- 👤 Nobuyoshi Abe
- 👤 Syozo Takatsu
- 👤 Kiyoshi Kanemaru
- 👤 Minoru Yokoyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 13:07
CPC Classifications
C; C09; C09C; C09C3/00; C09C3/06; C09C3/063; C01; C01P; C01P2004/00; C01P2004/80
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
121 words
A process for preparing a stable inorganic pigment composition having improved pigment characteristics wherein a fine amorphous silica is coated as a non-porous, continuous film on the surface of an inorganic pigment, said process comprising reacting sodium silicate and CO 2 in an aqueous slurry of said inorganic pigment by separately and gradually adding an aqueous solution of said sodium silicate and said CO 2 to said slurry simultaneously at rates which do not vary the pH of said slurry more than ±0.5, with the silica coating being formed under atmospheric pressure, under conditions such that the temperature is not lower than about 60° C. and under a pH of between 7 and 11 and with said inorganic pigment being ultramarine.
Claim 2
Dependent Claim
121 words
A process for preparing a stable inorganic pigment composition having improved pigment characteristics wherein a fine amorphous silica is coated as a non-porous, continuous film on the surface of an inorganic pigment, said process comprising reacting sodium silicate and CO 2 in an aqueous slurry of said inorganic pigment by separately and gradually adding an aqueous solution of said sodium silicate and said CO 2 to said slurry simultaneously at rates which do not vary the pH of said slurry more than ±0.5, with the silica coating being formed under atmospheric pressure, under conditions such that the temperature is not lower than about 60° C. and under a pH of between 7 and 11 and with said inorganic pigment being ultramarine.
Claim 3
Dependent Claim
20 words
The process of claim 1, wherein the aqueous slurry of the inorganic pigment is prepared by hydrothermal treatment with alkali.
Claim 4
Dependent Claim
39 words
The process of claim 1, wherein the aqueous slurry of the inorganic pigment is a slurry of pigment covered with a fine hydrous oxide of metal selected from the group consisting of zirconium, aluminum, titanium, cerium, antimony and magnesium.
Claim 5
Dependent Claim
14 words
The process of claim 1, wherein the acid gas is an acid exhaust gas.
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GB778695A
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US2913419A
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US4082905A
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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) | 1985-06-14 | 1985-12-14 | 1986-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-14 | 1989-12-14 | 1990-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-14 | 1993-12-14 | 1994-06-15 | $7700.00 | Window Closed / Lapsed |