SPHERICAL COMPOSITE POWDER OF PHENOL RESIN WITH INORGANIC PARTICLE AND PREPARATION THEREOF

PURPOSE:To improve durability, impact strength, and heat resistance by reacting a phenol or a phenol resin with an aldehyde in the presence of inorg. particles of which the surfaces have been made lipophilic in advance and a basic catalyst in an aq. medium under specified conditions. CONSTITUTION:The surfaces of inorg. particles (e.g. TiO2) are made lipophilic by treating with a coupling agent (e.g. vinyltrichlorosilane) or a surfactant. Then, one mol of a phenol or a phenol resin and 1-4mol of an aldehyde are reacted in the presence of the treated inorg. particles in a wt. of 0. 5-200 times as much as the phenol or phenol resin and 0.02-0.7mol of a basic catalyst (e.g. diethylenetriamine) in an aq. medium in such an amt. that the total solid content is 30-95wt.% under stirring with a peripheral stirrer speed of 1m/sec or higher at 80 deg.C or higher until the curing proceeds. The reaction product is cooled to 40 deg.C or lower to give a spherical composite phenol resin powder contg. the inorg. particles and having a number average particle diameter of 10-100mum and particle content of 80-99wt.%.