Surface-reacted precipitated calcium carbonate, process to make same, and uses thereof
OwnerDaniel E. Gerard, Patrick A.C. Gane +2inventors
InventorsDaniel E. Gerard, Patrick A.C. Gane, Joachim Schölkopf, Hans-Joachim Weitzel
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Abstract
The present invention relates to a process for the preparation of a surface-reacted precipitated calcium carbonate (PCC) pigment having an insoluble, at least partially crystalline calcium salt on its surface. In the process of the present invention, a PCC containing pigment is contacted with H3O+ ions and a solubilized anion in an aqueous medium in the presence of excess solubilized calcium ions to form the surface-reacted PCC having an insoluble, at least partially crystalline calcium salt of the anion formed on its surface.
Claims27
A surface-reacted precipitated calcium carbonate (PCC) pigment prepared by the process comprising the following steps:
- a) providing at least one precipitated calcium carbonate (PCC)-comprising pigment;
- b) providing H3O+ ions;
- c) providing at least one anion being capable of forming water-insoluble calcium salts, said anion being solubilized in an aqueous medium;
- d) contacting said PCC-comprising pigment with said H3O+ ions and with said solubilized anions in an aqueous medium to form a slurry of surface-reacted PCC-comprising pigment, wherein said surface-reacted PCC comprises an insoluble, at least partially crystalline calcium salt of said anion formed on the surface of at least part of the PCC provided in step a);
- characterised in that an excess of solubilized calcium ions is provided during step d).
Dependencies are inferred from the claim text.