SOLVENT-RESISTANT POROUS FINE PARTICLE OF UNIFORM PARTICLE DIAMETER AND ITS PRODUCTION

摘要

PURPOSE:To produce the titled porous fine particles excelling in solvent resistance and having a uniform particle diameter, by extracting solvent-soluble matter from a specified precursor of porous fine crosslinked polymer particles. CONSTITUTION:An aqueous dispersion of uncrosslinked fine polymer particles of a particle diameter of 0.5-2mum and a standard deviation of a particle distribution <=0.1mum is obtained by repeating the polymerization of initial seed particles comprising an uncrosslinked polymer obtained by polymerizing a noncrosslinking monomer in an aqueous medium at least twice. To this aqueous dispersion a monomer mixture comprising 99-99.95wt% noncrosslinking monomer and 1-0.05wt% crosslinking monomer is added and polymerized to obtain a crosslinkable fine polymer particles. 100-3,000pts.wt. monomer mixture comprising 50-90wt% noncrosslinkable monomer and 50-10wt% crosslinkable monomer is absorbed by 100pts.wt. above-produced fine particles and copolymerized in an aqueous medium to obtain a precursor of porous fine crosslinked polymer particles. Solvent-soluble matter is extracted from this precursor to obtain solvent-resistant porous fine particles having a uniform diameter, a particle diameter of 2-30mum and a standard deviation of a particle size distribution <=1mum.