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AssigneeMizusawa Kagaku Kogyo Kabushiki Kaisha
InventorsYujiro Sugahara, Kaichiro Miyazawa, Okitsu Hidetika, Mamoru Saito
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A coated pigment composition having improved resistance, especially to abrasion, is disclosed, said coated pigment composition consisting essentially of particles composed mainly of an inorganic color pigment and a continuous solid glass coating layer covering the surfaces of said pigment particles, said continuous solid glass coating layer being formed of a continuous phase composed mainly of an alkali polysilicate having the following mole composition MO.sub.2 : SiO.sub.2 = from 1 : 5 to 1 : 2 wherein M stands for an alkali metal component, in which the solid glass coating layer is present in an amount, as calculated as SiO.sub.2, of from 3 to 40 % by weight based on said pigment particles and the value of the specific surface area ratio, expressed by the following formula R.sub.s = S.sub.c /S.sub.p wherein S stands for the specific surface area (m.sup.2 /g) of uncoated pigment particles, S.sub.c stands for the specific surface area (m.sup.2 /g) of coated pigment particles, and R.sub.s stands for the specific surface area ratio, Is within a range of from 1.00 to 1.07.
A coated pigment composition having improved resistance, especially to abrasion, which consists essentially of particles composed mainly of an inorganic color pigment and a continuous solid glass coating layer covering the surfaces of said pigment particles, said continuous solid glass coating layer being formed of a continuous phase composed mainly of an alkali polysilicate having the following mole composition
A process for the preparation of coated pigment compositions having improved resistance, especially to abrasion, which comprises wetting particles composed mainly of an inorganic color pigment with an aqueous solution of an alkali polysilicate having the following composition
Dependencies are inferred from the claim text.