EP0143848A1
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EP
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Silica base for dentifrice and process for its preparation
Assignee: Taki Chemical Co Ltd
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Filing: 1984-02-28
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Granted: —
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Expires: 2004-02-28
Abstract
Abstract Silica base for dentifrice having excellent transparency and prolonged stability, desired abrasive ability, specific surface area of 270 to 500 m 2 /g (according to the BET method) or 5 to 60 m 2 /g (according to the CTAB method), and a refractive index of 1.455 to 1.470 and showing, after baking at 1100 C, a substantially amorphous X ray diffraction pattern, which can be prepared by reacting an alkali metal silicate solution with hydrochloric of sulfuric acid in the presence of an electrolyte, controlling the ratio of the rate of adding chloride or sulfate ion in a silica-precipitating step in which the pH of the reaction system is up to 10.0 to that in an acidifying step in which the pH is adjusted to 3.5 or less at the completion of the reaction to at least 3:2, and completing the acidifying step within 30 minutes.
Inventors
- 👤 Shozo Shinpo
- 👤 Tetsuo Fushino
- 👤 Akihiro Hachijo
- 👤 Shozo Ohtsu
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 01:48
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/18; C01B33/187; C01B33/193; A; A61; A61K; A61K8/00; A61K8/18; A61K8/19; A61K8/25; A61Q; A61Q11/00; C01P; C01P2002/00; C01P2002/02; C01P2006/00; C01P2006/12; C01P2006/60
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
54 words
A silica base material for dentifrice formulation, characterized by having a specific surface area by the BET method of 27 0 -500 m 2 /g-anhydride, and also, one by the CTAB method of 5- 60 m 2 /g-anhydride; giving virtually amorphous X-ray-aiffraction patterns after firing at 1100°C; and having a refractive index of 1.455-1.470.
Claim 2
Dependent Claim
54 words
A silica base material for dentifrice formulation, characterized by having a specific surface area by the BET method of 27 0 -500 m 2 /g-anhydride, and also, one by the CTAB method of 5- 60 m 2 /g-anhydride; giving virtually amorphous X-ray-aiffraction patterns after firing at 1100°C; and having a refractive index of 1.455-1.470.
Claim 3
Independent Claim
100 words
The method for the production of a silica base material for dentifrice formulation, characterized by the fact that the reaction between alkali metal silicate solution and hydrochloric or sulfuric acid under the presence of electrolyte is conducted in two stages; the silica crystallization stage for which the pH of reaction mixture is brought to 10.0, and the acidification stage for which the pH is finally brought down to 3.5 or less; the ratio of the rate of addition of chloride or sulfate ion between said two stages is at least 3:2; and the acidification is carried out within 30 minutes.
Claim 4
Independent Claim
100 words
The method for the production of a silica base material for dentifrice formulation, characterized by the fact that the reaction between alkali metal silicate solution and hydrochloric or sulfuric acid under the presence of electrolyte is conducted in two stages; the silica crystallization stage for which the pH of reaction mixture is brought to 10.0, and the acidification stage for which the pH is finally brought down to 3.5 or less; the ratio of the rate of addition of chloride or sulfate ion between said two stages is at least 3:2; and the acidification is carried out within 30 minutes.
Claim 5
Dependent Claim
18 words
The methos described in claim 2, where the electrolyte is previously added to the alkali metal silicate solution.
Claim 6
Dependent Claim
26 words
The method.described in claim 2, where the alkali metal silicate solution has a molar ratio, Si0 2/ X 2 0 (X denotes alkali metal), of 2-4.
Claim 7
Dependent Claim
28 words
The method described in claim 2, where the Si0 2 concentration of the alkalimetal silicate solution before the addition of hydrochloric or sulfuric acid is 5-15% by weight.
Claim 8
Dependent Claim
16 words
The method described in claim 2, where the electrolyte is alkali metal salt of mineral acid.
Claim 9
Dependent Claim
20 words
The method described in claim 2, where the amount of the electrolyte is 10-60% by weight of Si0 2 .
Claim 10
Dependent Claim
18 words
The method described in claim 2, where the concentration of hydrochloric or sulfuric acid is 5-15% by weight.
Claim 11
Dependent Claim
17 words
The method described in claim 2, where the reaction temperature during the silica crystallization stage is 60-100°C.
Claim 12
Dependent Claim
31 words
1 0 . The method described in claim 2, where the addition of hydrochloric or sulfuric acid during the silica crystallization stage is conducted to take 40 minutes to 4 hours.
References Cited (Backward Citations)
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