Patent US4448609A successfully refreshed from Google Patents.
US4448609A
Expired / Lapsed
US
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Process for the production of aqueous dispersions of pigmentary titanium dioxide
Assignee: Tronox Pigment UK Ltd
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Filing: 1982-03-25
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Granted: 1984-05-15
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Expires: 2002-03-25
Abstract
Abstract Stable high concentration aqueous slurries of pigmentary metal oxide particles having a hydrous oxide surface-treatment comprising alumina, for example alumina surface-treated pigmentary titanium dioxide, may be formed by the use of a specified combination of anionic and amine dispersants and a milling in the presence of grinding elements, for example in a sand mill, to develop suitable viscosity and gloss characteristics. The slurries may show thixotropic properties and are suitable for incorporation in vinyl silk aqueous emulsion paints.
Inventors
- 👤 Brian Tear
- 👤 David G. Othen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:31
CPC Classifications
C; C09; C09D; C09D17/00; C09D17/004; C09D17/007; C09D7/00; C09D7/40; C09D7/45; Y; Y10; Y10S; Y10S516/00; Y10S516/01; Y10S516/06
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
162 words
A process for the production of an aqueous dispersion of pigmentary titanium dioxide particles characterised by forming an aqueous dispersion of washed pigmentary titanium dioxide particles which have been surface treated with from 1.0 to 4.0% of alumina, raising the solids concentration of the said alumina surface-treated titanium dioxide particles to above 60% by weight, introducing into the dispersion, before or after the solids concentration thereof has been raised, a combination of dispersants comprising an amine dispersant in from 0.3% to 3.0% by weight of the alumina surface treated titanium dioxide, and an anionic dispersant in from 0.04% to 0.75% by weight of the alumina surface treated titanium dioxide and milling the raised solids concentration dispersion, containing the said combination of dispersants, in the presence of grinding elements to raise the gloss value given by the dispersion to at least 50 and the Brookfield viscosity value using spindle No. 3 and 60 r.p.m. given by the dispersion to from 400 to 3000.
Claim 2
Dependent Claim
162 words
A process for the production of an aqueous dispersion of pigmentary titanium dioxide particles characterised by forming an aqueous dispersion of washed pigmentary titanium dioxide particles which have been surface treated with from 1.0 to 4.0% of alumina, raising the solids concentration of the said alumina surface-treated titanium dioxide particles to above 60% by weight, introducing into the dispersion, before or after the solids concentration thereof has been raised, a combination of dispersants comprising an amine dispersant in from 0.3% to 3.0% by weight of the alumina surface treated titanium dioxide, and an anionic dispersant in from 0.04% to 0.75% by weight of the alumina surface treated titanium dioxide and milling the raised solids concentration dispersion, containing the said combination of dispersants, in the presence of grinding elements to raise the gloss value given by the dispersion to at least 50 and the Brookfield viscosity value using spindle No. 3 and 60 r.p.m. given by the dispersion to from 400 to 3000.
Claim 3
Dependent Claim
20 words
A process as claimed in claim 1 wherein the anionic dispersant is a polyacrylate, polyphosphate pyrophosphate, citrate, silicate or tartrate.
Claim 4
Dependent Claim
22 words
A process as claimed in claim 2 wherein the anionic dispersant is in the form of a sodium, potassium or ammonium salt.
Claim 5
Dependent Claim
17 words
A process as claimed in claim 1 wherein the amine dispersant is a secondary or tertiary amine.
Claim 6
Dependent Claim
14 words
A process as claimed in claim 4 wherein the amine dispersant is an alkanolamine.
Claim 7
Dependent Claim
28 words
A process as claimed in claim 4 wherein the quantity of the amine dispersant is not more than 2% by weight of the alumina surface-treated metal oxide particles.
Claim 8
Dependent Claim
40 words
A process as claimed in any preceding claim wherein the raised solids concentration dispersion containing the combination of dispersants is milled until less than 20% by weight of the pigmentary metal oxide particles are greater than 0.5% microns in diameter.
Claim 9
Dependent Claim
122 words
An aqueous dispersion of pigmentary titanium dioxide particles surface treated with from 1.0% to 4.0% of alumina, the dispersion having a concentration of said alumina surface-treated titanium dioxide particles of above 60% by weight and containing a combination of dispersants comprising an amine dispersant in at least 0.3% and not more than 2% and an anionic dispersant in at least 0.04% less than 0.6% by weight of the alumina surface-treated metal oxide particles less than 20% of the said alumina surface-treated metal oxide particles having a particle size greater than 0.5 microns in diameter, the dispersion giving a % gloss value of at least 50 and a Brookfield viscosity value, using spindle No. 3 and 60 r.p.m., of from 400 to 3000.
Claim 10
Dependent Claim
122 words
An aqueous dispersion of pigmentary titanium dioxide particles surface treated with from 1.0% to 4.0% of alumina, the dispersion having a concentration of said alumina surface-treated titanium dioxide particles of above 60% by weight and containing a combination of dispersants comprising an amine dispersant in at least 0.3% and not more than 2% and an anionic dispersant in at least 0.04% less than 0.6% by weight of the alumina surface-treated metal oxide particles less than 20% of the said alumina surface-treated metal oxide particles having a particle size greater than 0.5 microns in diameter, the dispersion giving a % gloss value of at least 50 and a Brookfield viscosity value, using spindle No. 3 and 60 r.p.m., of from 400 to 3000.
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) | 1987-05-15 | 1987-11-14 | 1988-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-15 | 1991-11-14 | 1992-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-15 | 1995-11-14 | 1996-05-15 | $7700.00 | Window Closed / Lapsed |