Hoechst Aktiengesellschaft

Hedwig Prell

Franz-Josef Dany

Gerhard Kalteyer

Gerhard Nolte

Joachim Kandler

Renate Adrian

Joachim Wortmann

Horst Klassen

Hermann Schrodter

In the process for the preparation of dicalcium phosphate dihydrate, which has a good compatibility with fluorine and stability to hydrolysis and causes the minimum possible after-thickening when used in tooth-pastes, by reaction of calcium carbonate suspended in water with an aqueous solution of orthophosphoric acid, precipitation of dimagnesium phosphate trihydrate, as a stabilizer, by reaction of aqueous solutions of a magnesium salt and of orthophosphoric acid in the presence of a basic compound and final filtration, drying and grinding of the precipitate, 0.2 to 0.8% by weight of polyphosphoric acid, calculated with respect to the dicalcium phosphate dihydrate precipitated in the reaction mixture, is added to the reaction mixture as a further stabilizer.

Process for the preparation of a dicalcium phosphate dihydrate suitable

In the process for the preparation of dicalcium phosphate dihydrate, which has a good compatibility with fluorine and stability to hydrolysis and causes the minimum possible after-thickening when used in toothpastes, by reaction of calcium carbonate suspended in water with an aqueous solution of orthophosphoric acid, precipitation of dimagnesium phosphate trihydrate, as a stabilizer, by reaction of aqueous solutions of a magnesium salt and of orthophosphoric acid in the presence of a basic compound and subsequent addition of tetrasodium pyrophosphate to the reaction mixture as a further stabilizer and final filtration, drying and grinding of the precipitate, 0.2 to 0.6% by weight of tetrasodium pyrophosphate, calculated with respect to the dicalcium phosphate dihydrate precipitated in the reaction mixture, is added to the aqueous reaction mixture.

Tooth pastes contain a cleaning agent consisting of dicalcium phosphate-dihydrate. The cleaning agent has an adsorptive power of more than 60 g H.sub.2 /100 g. Disclosed is the cleaning agent and a process for making it.

Tooth pastes, cleaning agent for tooth pastes based on dicalcium

Desensitized free-flowing red phosphorus. The phosphorus is comprised of a homogeneous blend consisting of between about 80 and 98 weight% of red phosphorus having a particle size of up to about 2 mm, and of between about 2 and 20 weight% of an organic or organo-silicon compound desensitizer. The desensitizer is liquid, inactive with respect to red phosphorus and has a minor vapor pressure at room temperature at atmospheric pressure.

Growing community of inventors

Hurth, Germany

Hedwig Prell