Heat-sensitive recording paper and filler therefor

摘要

Disclosed is a filler for a heat-sensitive recording paper, which comprises an amorphous silicate having a composition represented by the following oxide molecular ratio: MO:SiO2=0.01:1 to 1.1:1 wherein M stands for at least one member selected from the group consisting of calcium, barium and zinc, or a product obtained by partially neutralizing said silicate with carbonic acid, said filler having a BET specific surface area of 10 to 70 m2/g and a bulk density of 0.14 to 0.30 g/cc and also having such a secondary particle size distribution that secondary particles having a size smaller than 4 mu m, as determined by the centrifugal precipitation method, occupy at least 70% by weight of the total particles.