Mizusawa Industrial Chemicals, Ltd.

Seikichi Takahashi

Masahide Ogawa

Teiji Sato

Kinichi Ono

Masanori Tanaka

Koichi Usui

Kunio Goto

Toshio Kitsu

Seiji Kojima

Masao Takahashi

Maso Takahashi

Disclosed is a filler for ink jet recording paper, said filler being composed of amorphous silica having a median diameter, measured by the coulter counter method, of 2 to 15 .mu.m, an oil absorption of at least 180 ml/100 g, a refractive index, measured by the solvent method, of at least 1.450, and a moisture absorption, measured when it is caused to absorb moisture for 200 hours at a relative humidity of 90% and a temperature of 25.degree. C., of at least 35%.

Ink jet recording paper with amorphous silica filler

Filler for ink jet recording paper

Disclosed is a filler for a heat-sensitive recording paper comprising finely divided amorphous silica having a BET specific surface area of 10 to 100 m.sup.2 /g and a bulk density of 0.14 to 0.30 g/cc, said finely divided amorphous silica having such a secondary particle size distribution that secondary particles having a size smaller than 4 microns, as measured by the centrifugal precipitation method, occupy at least 90% by weight of the total particles. This filler is excellent in the effects of preventing the background coloration, improving the lubricating property, preventing the adhesion of scum and improving the image density.

Heat-sensitive recording paper and filler therefor

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Nakajo, Japan

Seikichi Takahashi