Abstract: A surface-treated heavy calcium carbonate is provided which is useful for a film exactly controlled in its pore diameter and for easily hydrolyzable polyester resins. A heavy calcium carbonate is also provided which is compounded in a curable resin such as a one-component moisture-curable adhesive and a sealant either without any pre-drying treatment or by simple pre-drying treatment. A surface-treated heavy calcium carbonate satisfying 13,000?A?25,000, 0.8?B?3.0, C?0.55, and 0?D1?1000, or 8,000?A?25,000, 0.8?B?15, 0?C1?1000, and 0?C2?150 wherein: A: specific surface area (cm2/g), B: average particle diameter (?m): 50% particle diameter (d50) (?m), C: 10% particle diameter (?m), D1, C1: water content at between 25° C. and 300° C. by a Karl-Fischer method (heating vaporization method) (ppm), and C2: water content at between 200° C. and 300° C. by the same method.

Abstract: A surface-treated heavy calcium carbonate is provided which is useful for a film exactly controlled in its pore diameter and for easily hydrolyzable polyester resins. A heavy calcium carbonate is also provided which is compounded in a curable resin such as a one-component moisture-curable adhesive and a sealant either without any pre-drying treatment or by simple pre-drying treatment. A surface-treated heavy calcium carbonate satisfying 13,000?A?25,000, 0.8?B?3.0, C?0.55, and 0?D1?1000, or 8,000?A?25,000, 0.8?B?15, 0?C1?1000, and 0?C2?150 wherein: A: specific surface area (cm2/g), B: average particle diameter (?m): 50% particle diameter (d50) (?m), C: 10% particle diameter (?m), D1, C1: water content at between 25° C. and 300° C. by a Karl-Fischer method (heating vaporization method) (ppm), and C2: water content at between 200° C. and 300° C. by the same method.

Abstract: A filler for porous films is provided which is easy to be mixed with a resin, has good dispersibility in a resin, and provides a porous film useful for a light reflector of, for example, a liquid crystal display and a lighting apparatus and a porous film useful for a diaphragm (separator) between electrodes of a battery. A filler comprises inorganic particles surface treated with a surfactant (A) and a compound (B) having a chelating function to an alkaline earth metal.