Patent ID: 7199173

Claim:
An agglomerate comprising fine primary particles of a synthesized calcium carbonate, the agglomerate satisfying the following expressions (a) to (e): 0.5≦dp 50 ≦20 [μm] (a); 0≦α≦2.5 [−] (b); 30≦Sw [m 2 /g] (c); 20≦St≦150 [MPa] (d) and 200≦Sta≦600 [MPa] (e), wherein dp 50 : the average particle diameter [μm] of the agglomerate measured by Microtrac-FRA, a laser analysis type particle size distribution measurement apparatus, α: the value calculated by dividing the difference between the particle diameter d 90 of cumulative 90% minus sieve particles of the agglomerate and the particle diameter d 10 of cumulative 10% minus sieve particles of the agglomerate calculated by the Microtrac-FRA, a laser analysis type particle size distribution measurement apparatus by the average particle diameter dp 50 according to the following equation: α=( d 90 −d 10 )/dp 50 , d 90 : the particle diameter of cumulative 90% minus sieve particles of the agglomerate measured by the Microtrac-FRA, a laser analysis type particle size distribution measurement apparatus, d 10 : the particle diameter of cumulative 10% minus sieve particles of the agglomerate measured by the Microtrac-FRA, a laser analysis type particle size distribution measurement apparatus, Sw: the BET specific surface area of the agglomerate [m 2 /g], St: the tensile strength [MPa] required to break the agglomerate with the particle diameter 4 μm, measured by a MCT-W500-J micro compression testing machine manufactured by Shimadzu Corporation under conditions of 9.8 mN in load and 0.892405 mN/sec in load speed, and Sta: the tensile strength [MPa] required to break 30% of the particle diameter of the agglomerate with the particle diameter 4 μm, measured by a MCT-W500-J micro compression testing machine manufactured by Shimadzu Corporation under conditions of 9.8 mN in load and 0.892405 mN/sec in load speed.