Abstract: Disclosed is a calcium carbonate which is 25 to 55 m.sup.2 /g in BET specific surface area, 5 to 110 in the ratio of BET specific surface area (m.sup.2 /g)/mean particle size (.mu.m), at least 120 ml/100 g in oil absorption as determined by the Ogura method and at least 1.8 g/g in water absorption, and process for preparing the same. The calcium carbonate is formulated into a coating composition for forming a heat-sensitive recording layer or intermediate layer of a heat-sensitive recording paper or for forming an ink-jet recording paper.

Abstract: A composition comprising a thermoplastic resin and an activated mineral filler, said mineral filler consisting of particles of at least one aluminosilicate-type mineral containing alakali metal ions as cations in its crystal structure, the surfaces of said particles being covered monomolecularly with at least one ethylenically unsaturated organic acid, having 10 or less carbon atoms, which is bonded to the metal ions on the surfaces of said particles and retains ethylenic double bonds unreacted. On being mixed under application of heat to cause reaction, this composition gives a molded article excellent in compatibility and physical properties such as stiffness, toughness, ductility, fatigue properties, water resistance, transparency, etc.