Maruo Calcium Company Limited

Kouhei Sako

Hidemitsu Kasahara

Hisakazu Hojo

Shigeo Takiyama

Makoto Nagamatsu

Tomonori Kosaka

Homare Kudo

Hisakazu Kojo

Provided is a calcium carbonate filler which gives films and the like excellent in moldability, dispersibility, gasmark (bubbles), hue, and further, excellent in optical properties such as reflectivity and light resistance when incorporated into a resin to prepare a resin composition.

Calcium carbonate filler for resin and resin composition including said filler

Provided is a surface treated calcium carbonate filler for resins, which comprises calcium carbonate particles, the surface of which has been treated with at least one surface active agent (A) selected from the group consisting of saturated fatty acids, unsaturated fatty acids, alicyclic carboxylic acids, resin acids, and salts thereof and with at least one compound (B) having the ability to chelate alkaline earth metals, the compound (B) being selected from the group consisting of phosphonic acids, polycarboxylic acids, and salts thereof. The surface treated calcium carbonate filler for resins of the present invention deteriorates little with time, has satisfactory dispersibility in resins, and can give a sheet or film which has a satisfactory balance among durability, weatherability, strength, and thermal stability, and is useful as a battery separator or a light reflector.

Surface treated calcium carbonate filler for resin and resin composition containing the filler

A calcium carbonate filler for a resin, in which the content rate of particles having a particle diameter of 0.26 &#x3bc;m or less is 30% or less in a number particle size distribution diameter measured (Mac-VIEW manufactured by Mountech) from an electron micrograph, and which satisfies the following expressions (a) to (c) is provided.5/5&#x2266;3&#x2003;&#x2003;(a)1&#x2266;&#x2266;8 (m/g)&#x2003;&#x2003;(b)&#x2266;300 (ppm)&#x2003;&#x2003;(c)whereinDms5: A 5% diameter (&#x3bc;m) accumulated from a small particle side in a volume particle size distribution by a laser diffraction particle size distribution measuring device (MASTERSIZER2000 manufactured by Malvern); Dmv5: A 5% diameter (&#x3bc;m) accumulated from a small particle side in a number particle size distribution in a particle diameter (Mac-VIEW manufactured by Mountech) measured with an electron microscope; Sw: A BET specific surface area (Macsorb manufactured by Mountech) (m/g); Mo: A water amount (ppm) by the Karl Fischer method at 200 to 300&#xb0; C. The calcium carbonate filler for a resin of the present invention contains less fine powders, has a particle size which has been adjusted to a specific particle size, and contains less volatile components such as water etc. and, even when it is incorporated into a resin having a high processing temperature at a high concentration, problems such as foaming etc. are solved.

Calcium carbonate filler for resin, process for producing the same, and resin composition containing the filler

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Hyogo, Japan

Kouhei Sako