Patent ID: 7341704

Claim:
A surface-treated calcium carbonate that has been treated with at least one hydrophobic organic surface treating agent selected from the group consisting of saturated fatty acids, unsaturated fatty acids, alicyclic carboxylic acids, resin acids, modified resins, alkali metal salts thereof, alkaline earth metal salts thereof, ammonium salts thereof and amine salts thereof, wherein the surface-treated calcium carbonate satisfies the following formulae (a), (b), (c) and (d): 20≦Sw≦200 (m 2 /g) (a) 1.0≦As≦7.5 (mg/m 2 ) (b) 0.003≦Dxp≦0.03 (μm) (c) 50≦ Dyp/Dxp≦ 180, (d) wherein: Sw: BET specific surface area determined by nitrogen adsorption method (m 2 /g); As: reduced heat amount per unit specific surface area calculated by the following equation (mg/m 2 ): (reduced heat amount mg per 1 g of the surface-treated calcium carbonate at 200° C. to 500° C.)/Sw; Dxp: average pore diameter (μm) at which an increased amount of mercury penetration [integration of increased amounts of pore volume/log (average pore diameter)] reaches the maximum value (Dys) in distribution of pore in the pore range of 0.001 to 0.1 μm in a method of mercury penetration; Dyp: maximum value of an increased amount of mercury penetration (ml/g); and Dyp/Dxp: amount of an average pore diameter.