Crosslinked resin particles, crosslinked resin particle emulsion for use in producing the crosslinked resin particles, and method for producing crosslinked resin particles

摘要

Fine crosslinked-resin particles having such a high degree of crosslinking that good mechanical strength, heat resistance and solvent resistance can be developed. The fine crosslinked-resin particles have a mean particle diameter in the range of not less than 0.01 mum to not more than 0.30 mum and are such that when 10 g of powders comprising the fine crosslinked-resin particles and 20 g of iron powders are put in a 300 ml glass ball mill container containing 5 g of polyamide ball of a diameter of 2 mm, 10 g of polyamide ball of a diameter of 5 mm and 10 g of polyamide ball of a diameter of 10 mm and are agitated and mixed by rotating the ball mill container at a rotation speed of 100 rpm for 30 minutes and, then, the mixed powders are taken out from the ball mill container and are observed by an electron microscope, not more than two defective fine crosslinked-resin particles are observed out of 20 fine crosslinked-resin particles arbitrarily selected from the mixed powders. The fine crosslinked-resin particles are produced by drying fine crosslinked-resin particle emulsion obtained by ethylenic unsaturated monomers, which contain not less than 20 weight % of monomer having at least two ethylenic unsaturated groups in a molecule and are hardly soluble in water, being polymerized in a dispersion medium containing water as its major component.