Disintegration type, crosslinked acrylic resin particles

Claim 1

Disintegration crosslinked acrylic resin particles having an average grain diameter of 0.01 to 250 μ and containing metal ester bond bearing crosslinks uniformly distributed within the particle bodies, but wherein the crosslinked density is higher in the center than the surface layer of the particles, said particles prepared by the method wherein a monomer mixture of (A) 5 to 98% by weight of at least one metal ester bond bearing multifunctional polymerizable monomer represented by the formula: ##STR6## in which R 2 is hydrogen or a methyl group; X is a radical selected from the group consisting of ##STR7## R' is a hydrogen, methyl or ethyl group; R is a hydrocarbon residue having 1 to 20 carbon atoms; p is 0 or 1 to 5; R 1 is a hydrocarbon residue having 1 to 10 carbon atoms; M stands for metal whose valency is 2 or more; Y is an organic residue; m and n are positive integers fulfilling the requirements of 2≦m≦l q and n=q-m in which q is equal to the metal valency, and (B) 95 to 2% by weight of at least one polymerizable monomer other than said (A) having at least one, β-ethylenically unsaturated bond, is polymerized in a reaction medium which cannot dissolve the formed polymer and the thus-formed polymer particles are separated from the said medium.