PURPOSE: To obtain solvent-resistant porous fine crosslinked polymer particles of a uniform particle diameter, by allowing specified fine uncrosslinked polymer particles to absorb a noncrosslinking monomer, a crosslinking monomer and a pore modifier, subjecting these particles to copolymerization treatment and extracting solvent-soluble matter from the treated particles.
CONSTITUTION: Fine uncrosslinked polymer particles (A) are allowed to absorb a monomer mixture comprising 50W90wt% noncrosslinking monomer and 50W10wt% crosslinking monomer and a pore modifier, and the particles are subjected to copolymerization treatment in an aqueous medium to obtain a precursor of fine crosslinked polymer particles. Solvent-soluble matter is extracted from the obtained precursor (B) to obtain the purpose fine particles. Said fine uncrosslinked polymer particles (A) are obtained by repeating at least three times an operation of increasing the diameters of particles obtained by adding water and a noncrosslinking monomer to an aqueous dispersion of seed particles and subjecting the resulting dispersion to polymerization treatment and using the obtained grown particles as seed particles in the subsequent operation. In this operation, an uncrosslinked polymer obtained by treating a noncrosslinking monomer in an aqueous medium is used as the initial seed particles. These particles have a particle diameter of 0.5W10μ and a standard deviation of a particle size distribution ≤0.1μ.
TOMITA TOSHIHIKO
MOROISHI YUTAKA
SAWAGUCHI MAREYOSHI
NODA KEN
