Omya International Ag

Shiraishi Kogyo Kaisha, Ltd.

Omya Development Ag

Gernot Primosch

Michael Pohl

Christian Rainer

Yoshisada Kayano

Shinjiro Fujiwara

Peter-Christian Rainer

Peter Christian Rainier

The present invention provides a process for preparing a precipitated calcium carbonate product. The process comprises the steps of preparing an aqueous suspension of precipitated calcium carbonate seeds by carbonating a suspension of Ca(OH)in the presence of 0.005 to 0.030 moles of Sr, in the form of Sr(OH), based upon moles of Ca(OH)prior to or during carbonation; forming an aqueous suspension of a precipitated calcium carbonate product by carbonating a slurry of Ca(OH)in the presence of 0.5 to 5% by dry weight of the precipitated calcium carbonate seeds, wherein the precipitated calcium carbonate seeds have a D50 that is less than the D50 of the precipitated calcium carbonate product and the precipitated calcium carbonate seeds have an aragonitic polymorph content greater than or equal to the precipitated calcium carbonate product.

Process for obtaining precipitated calcium carbonate

A calcium carbonate having a surface treated with a surface treating agent containing a sodium salt or a potassium salt of a fatty acid, the surface treating agent containing a sodium salt or a potassium salt of palmitic acid in an amount of PW in terms of acid, the surface treating agent containing a sodium salt or a potassium salt of stearic acid in an amount of SW in terms of acid, a total amount of PW and SW being PW+SW&#x2267;90, a ratio of PW to SW being 0.30&#x2266;PW/SW&#x2266;1.1, the surface-treated calcium carbonate having a BET specific surface area of SAof 15&#x2266;SA2&#x2266;48, and the sodium salt or the potassium salt of the fatty acid being used for the treatment in an amount of FA and a ratio (FA/SA) being 0.095&#x2266;FA/SA&#x2266;0.135.

Surface-treated calcium carbonate and paste-like resin composition containing same

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Villach, Austria

Gernot Primosch