Maruo Calcium Company Limited

Shigeru Sakaguchi

Katsunori Fukumoto

Takaaki Nishioka

Tatsunari Yago

Ryoji Utsumi

Yusuke Hayashi

Provided are a surface-treated calcium carbonate filler useful in a curable resin, for imparting performance having excellent heat resistance, color fastness, strength and elongation, and a curable resin containing the filler. A surface-treated calcium carbonate filler for a curable resin composition, in which calcium carbonate synthesized using compact limestone is treated by a surface treatment agent, the surface-treated calcium carbonate filler satisfying the following formulae (1) to (4):0&#x2264;Mg&#x2264;2000,&#x2003;&#x2003;(1)0&#x2264;Fe&#x2264;200,&#x2003;&#x2003;(2)70&#x2264;SFa&#x2264;100, and&#x2003;&#x2003;(3)0&#x2264;Ufa&#x2264;30,&#x2003;&#x2003;(4)Mg: a proportion [ppm] of magnesium contained in surface-treated calcium carbonate, Fe: a proportion [ppm] of iron contained in surface-treated calcium carbonate, SFa: a proportion [wt %] of saturated fatty acid in the surface treatment agent comprising a water-soluble monovalent salt of a fatty acid, and UFa: a proportion [wt %] of unsaturated fatty acid in the surface treatment agent comprising a water-soluble monovalent salt of a fatty acid.

Surface-treated calcium carbonate filler for curable resin composition, and curable resin composition containing filler

The surface-treated calcium carbonate filler having a floc structure is provided which can provide a curable resin composition which has a high thixotropic property, exerts a high elongation degree at a low modulus, and has such a restoring rate that a load to be applied onto an adherend is reduced particularly by mixing in the curable resin composition, and the curable resin composition containing the filler. The surface-treated calcium carbonate filler is comprised of a synthetic calcium carbonate which is surface-treated with a fatty acid-based organic material containing a fatty acid salt and has a floc structure, wherein a ratio Sr of the amount of a fatty acid salt for which a counter ion is of monovalent, and which is contained in surface-treating agents eluted as free materials when the surface-treated calcium carbonate is refluxed with ethanol, to the total amount of the surface-treating agents is 10 to 30 wt %, and a porosity Po at the time of the consolidation of the surface-treated calcium carbonate is 38 to 45 wt %.

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Akashi, Japan

Shigeru Sakaguchi