摘要 |
A method of producing a calcium carbonate, magnesium carbonate or calcium-magnesium carbonate which is surface modified with an organic material wherein the carbonate in substantially dry, particulate form is contacted with an organic monomer, copolymers or a prepolymer, and surface polymerization or reaction in situ on the carbonate in the presence of a gaseous hydrogen atmosphere is effected. In the case where the carbonate has been wet processed and residues of a dispersing agent employed remain as a coating on the carbonate particles after drying, a minor amount of a calcined kaolin or TiO2 is used as a polymerization catalyst. When the carbonate has been dry ground so that the particles are free from processing chemicals, no catalyst is needed to initiate the polymerization.
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