Patent US5226930A successfully refreshed from Google Patents.
US5226930A
Expired / Lapsed
US
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Method for preventing agglomeration of colloidal silica and silicon wafer polishing composition using the same
Assignee: Pharmacia Searle Ltd
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Filing: 1992-03-16
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Granted: 1993-07-13
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Expires: 2012-03-16
Abstract
Abstract A method is provided for preventing agglomeration of a colloidal silica comprising trialkylsilyating part of silanol groups on the surface of silica particles of the colloidal silica with a trialkylhalosilane or a hexaalkyldisilazane in an amount from about 0.1-10 mole % based on the silanol groups on the surface of the silica particles.
Inventors
- 👤 Shigeo Sasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:13
CPC Classifications
H; H10; H10P; H10P52/00; H10P52/40; H10P52/402; C; C09; C09K; C09K3/00; C09K3/14; C09K3/1409
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
48 words
A method for treating a colloidal silica comprising: (A) forming an aqueous colloidal silica dispersion from an aqueous sodium silicate solution, (B) mixing a trialylhalosilane with said aqueous colloidal silica dispersion to trialkylsilylate a part of silanol groups on a surface of silica particles of said colloidal silica.
Claim 2
Independent Claim
48 words
A method for treating a colloidal silica comprising: (A) forming an aqueous colloidal silica dispersion from an aqueous sodium silicate solution, (B) mixing a trialylhalosilane with said aqueous colloidal silica dispersion to trialkylsilylate a part of silanol groups on a surface of silica particles of said colloidal silica.
Claim 3
Dependent Claim
26 words
The method of claim 1, wherein said colloidal silica has a silica concentration of 20 to 50% by weight and a particle 5 to 1000 μm.
Claim 4
Dependent Claim
12 words
The method of claim 1, wherein said trialkylhalosilane is trimethylchlorosilane or trimethylbromosilane.
Claim 5
Dependent Claim
24 words
The method of claim 1, wherein said colloidal silica is treated with a cationic exchange resin to remove the alkali metal ion contained therein.
Claim 6
Dependent Claim
20 words
The method of claim 1, wherein said trialkysilylation is reacted with said colloidal silica for 30 minutes to 10 hours.
Claim 7
Dependent Claim
30 words
The method of claim 1, wherein said trialkysilylation is achieved by mixing 0.1 to 5% by weight, based on the weight of silica in said colloidal silica, of a trialkylhalosilane.
References Cited (Backward Citations)
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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) | 1996-07-12 | 1997-01-11 | 1997-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-12 | 2001-01-11 | 2001-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-12 | 2005-01-11 | 2005-07-13 | $7700.00 | Window Closed / Lapsed |