US3957526A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Titanium dioxide pigments and fillers
Assignee: Commonwealth Scientific and Industrial Research Organisation
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Filing: 1974-02-19
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Granted: 1976-05-18
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Expires: 1994-02-19
Abstract
Abstract A method of modifying the surface properties of titanium dioxide pigments and fillers by forming on the particles a surface coating of an aluminium compound, the coating having a significant number of acidic sites with pKa values of less than 2.8.
Inventors
- 👤 Jonathan Howard Hodgkin
- 👤 David Geoffrey Hawthorne
- 👤 Jean Drummond Swift
- 👤 David Henry Solomon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 02:12
CPC Classifications
C; C09; C09C; C09C3/00; C09C3/006; C09C1/00; C09C1/36; C09C1/3692; C01; C01P; C01P2004/00; C01P2004/80; C01P2006/00; C01P2006/22; C01P2006/90
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
40 words
Pigmentary titanium dioxide comprising the reaction product of a. titanium dioxide particles coated with a compound of aluminium and having on their surface a number of acidic sites with pKa values of less than 2.8 and b. an organic base.
Claim 2
Dependent Claim
40 words
Pigmentary titanium dioxide comprising the reaction product of a. titanium dioxide particles coated with a compound of aluminium and having on their surface a number of acidic sites with pKa values of less than 2.8 and b. an organic base.
Claim 3
Dependent Claim
21 words
Pigmentary titanium dioxide as claimed in claim 1 wherein the titanium dioxide particles are also coated with a compound of silicon.
Claim 4
Dependent Claim
27 words
Pigmentary titanium dioxide as claimed in claim 1 wherein the organic base is selected from the group consisting of amines, amides, aminoesters, alcohols, esters, ketones and ethers.
Claim 5
Dependent Claim
24 words
Pigmentary titanium dioxide as claimed in claim 1 wherein the organic base is selected from the group consisting of unsaturated amines and unsaturated alcohols.
Claim 6
Independent Claim
40 words
A method of producing pigmentary titanium dioxide which comprises mixing titanium dioxide particles coated with a compound of aluminium and having on their surfaces a number of acidic sites with a pKa value less than 2.8 with an organic base.
Claim 7
Independent Claim
40 words
A method of producing pigmentary titanium dioxide which comprises mixing titanium dioxide particles coated with a compound of aluminium and having on their surfaces a number of acidic sites with a pKa value less than 2.8 with an organic base.
Claim 8
Dependent Claim
84 words
A method as claimed in claim 5 wherein said coated titanium dioxide having acidic surfaces are formed by a process comprising: a. forming an aqueous slurry of titanium dioxide particles coated with a compound of aluminium, said slurry having a pH of less than 5, b. recovering the particles from said slurry while maintaining the pH value below 5, and c. heating the recovered particles for a sufficient length of time to form upon their surface acidic sites having a pKa value below 2.8.
Claim 9
Dependent Claim
20 words
A process as claimed in claim 6 wherein the titanium dioxide particles are also coated with a compound of silicon.
Claim 10
Dependent Claim
25 words
A process as claimed in claim 6 wherein the organic base is selected from the group consisting of an unsaturated amine and an unsaturated alcohol.
Claim 11
Dependent Claim
24 words
A process as claimed in claim 5 wherein the titanium dioxide particles are heated to remove water before being mixed with the organic base.
Claim 12
Dependent Claim
36 words
A process as claimed in claim 5 wherein the titanium dioxide particles and the organic base are mixed in the presence of a nonaqueous solvent for the base which is less basic than the organic base.
Claim 13
Dependent Claim
13 words
Pigmentary titanium dioxide of claim 1 wherein said organic base is an amine.
Claim 14
Dependent Claim
14 words
A method as claimed in claim 5 wherein said organic base is an amine.
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) | 1979-05-18 | 1979-11-17 | 1980-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-18 | 1983-11-17 | 1984-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-18 | 1987-11-17 | 1988-05-18 | $7700.00 | Window Closed / Lapsed |