Mizusawa Industrial Chemicals, Ltd.

Yuuzi Washio

Masahide Ogawa

Kiyoshi Abe

Masao Takahashi

Toshio Kitsu

Kazumitsu Enomoto

The amorphous silica has a large apparent specific gravity despite of its BET specific surface area of 200 to 500 m.sup.2 /g, has an oil absorption amount of as small as 50 to 120 ml/100 g, has an agglomeration degree (D1/D0=DA) defined by the ratio of silica elementary particle diameter D0 to primary particle diameter D1 of from 10 to 50, and has nearly a spherical particulate structure which is quite different from that of the conventional gelation method silica (DA=OO). The amorphous silica-type filler exhibits excellent properties in regard to handling, processability, dispersion property and abrasion-resistant property and, when added as, for example, an anti-blocking agent, makes it possible to obtain resin films having transparency and scratch-resistant property without fisheyes or voids. Owing to the above properties, the amorphous silica that is used as a filler for the heat-sensitive recording papers suppresses ground fogging, improves the image concentration, makes it possible to apply a highly viscous coating solution since the filler dispersed in an aqueous solution creates very small viscosity, and imparts excellent abrasion resistance to the apparatus during the step of coating.

Amorphous silica filler

The amorphous silica has a large apparent specific gravity despite of its BET specific surface area of 200 to 500 m.sup.2 /g, has an oil-absorption amount of as small as 50 to 120 ml/100 g, has an agglomeration degree (D1/D0=DA) defined by the ratio of silica elementary particle diameter D0 to primary particle diameter D1 of from 10 to 50, and has nearly a spherical particulate structure which is quite different from that of the conventional gelation method silica (DA=.infin.). The amorphous silica-type filler exhibits excellent properties in regard to handling, processability, dispersion property and abrasion-resistant property and, when added as, for example, an anti-blocking agent, makes it possible to obtain resin films having transparency and scratch-resistant property without fisheyes or voids. Owing to the above properties, the amorphous silica that is used as a filler for the heat-sensitive recording papers suppresses ground fogging, improves the image concentration, makes it possible to apply a highly viscous coating solution since the filler dispersed in an aqueous solution creates very small viscosity, and imparts excellent abrasion resistance to the apparatus during the step of coating.

The amorphous silica has a large apparent specific gravity despite of its BET specific surface area of 20 to 500 m.sup.2 /g, has an oil absorption amount of as small as 50 to 120 ml/100 g, has an agglomeration degree (D1/D0=DA) defined by the ratio of silica elementary particle diameter D0 to primary particle diameter D1 of from 10 to 50, and has nearly a spherical particulate structure which is quite different from that of the conventional gelation method silica (DA=.infin.). The amorphous silica-type filler exhibits excellent properties in regard to handling, processability, dispersion property and abrasion-resistant property and, when added as, for example, an anti-blocking agent, makes it possible to obtain resin films having transparency and scratch-resistant property without fisheyes or voids. Owing to the above properties, the amorphous silica that is used as a filler for the heat-sensitive recording papers suppresses ground fogging, improves the image concentration, makes it possible to apply a highly viscous coating solution since the filler dispersed in an aqueous solution creates very small viscosity, and imparts excellent abrasion resistance to the apparatus during the step of coating.

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Niigata, Japan

Yuuzi Washio