Taki Chemical Co., Ltd.

Lion Corporation

Tetsuo Fushino

Shozo Ohtsu

Akihiro Hachijo

Shozo Shinpo

Silica base material for dentifrice having excellent transparency, prolonged stability, and desired abrasiveness; has a specific surface area of 270-500 m.sup.2 /g as measured by BET method and 5-60 m.sup.2 /g by CTAB method, gives virtually amorphous X-ray diffraction pattern after firing at 1100.degree. C., and has a refractive index of 1.455-1.470. This base material can be prepared by reacting an alkali metal silicate solution with hydrochloric acid or sulfuric acid in the presence of an electrolyte, controlling the ratio of the rate of addition of chloride ion or sulfate ion to be at least 3:2 between the acidification stage in which the pH at the completion of the reaction is brought to 3.5 or less, and the silica crystallization stage in which the pH of the reaction system if brought to 10.0, and carrying out the acidification stage within 30 minutes.

Silica base for dentifrice and process for its preparation

Process for preparing silica base for dentifrice

The present invention provides a synthetic amorphous zirconium-bonded silicate obtained by reacting, as main starting materials, a water-soluble alkali-metal silicate with an inorganic zirconyl salt and a mineral acid, in which zirconium is bonded to silica at the ratio of ZrO.sub.2 to SiO.sub.2 being 0.1 to 10 weight percent, which silicate is useful as a dentifrice base material and also as a filler for rubber.

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Takasago, Japan

Tetsuo Fushino