PURPOSE: To make controllable particle size in a wide range by grafting a vinyl monomer or rubber particles formed by crosslinking dihydroxy functional polydiorganosiloxane.
CONSTITUTION: A dihydroxy functional polydiorganosiloxane of formula I [where R is methyl, ethyl or the like; and (x) is 10-100] having 0.005-0.15 Pas viscosity at 25°C, a grafting agent mode of a vinyl functional polysiloxane of formula II [where R5 is H, methyl or the like; and (p) is 1-6], an emulsifier, water and a crosslinking agent made of a polyalkoxysilane are homogenized to prepare an emulsion of polydiorganosiloxane particles. This emulsion is maintained at ≤pH5 and reacted in the presence of an acid catalyst at a temp. of 15-30°C to form vinyl functional silicone rubber particles having the desired mol.wt. and crosslinking degree and the pH is adjusted to 6-8. The rubber particles and a vinyl monomer are then graft-polymerized.
KEBUIN RIIDO KITSUDAA
BAIJIYAYA KAMAA KURUGANTEI
FURONGUUROANGU SHIEU
