Filler for heat-sensitive recording paper and process for producing the same
AssigneesNissan Chemical Industries, Ltd., Shionogi & Co., Ltd.
InventorsMasao Kubo, Akihiro Shiroishi, Ikuo Uno, Takashi Nishiyama
Life of this patent
Estimating the term…
Abstract
Disclosed herein is a filler for heat-sensitive recording paper which comprises amorphous silica obtained by reacting hydrosilicofluoric acid and/or an alkali salt thereof with an alkali (such as ammonia and dimethylamine). The filler has a solid acid strength (pk.sub.a) of +6.8 to 3.3, and oil absorption value of 120 to 200 ml/100 g, a nitrogen adsorption specific surface area of 110 to 350 m.sup.2 /g (by BET method), and a water vapor adsorption specific surface area of 200 to 300 m.sup.2 /g (by BET method).
Claims1
A coating composition for heat-sensitive recording paper which comprises a heat-sensitive dye, a binder and an amorphous silica filler obtained by reacting hydrosilicofluoric acid and/or an alkali salt thereof with an alkali and having a solid acid strength (pk.sub.a) of +6.8 to +3.3, an oil absorption value of 120 to 200 ml/100 g, a nitrogen adsorption specific surface area of 110 to 350 m.sup.2 /g (by BET method), and a water vapor adsorption specific surface area of 200 to 300 m.sup.2 /g (by BET method).
Dependencies are inferred from the claim text.