Macroreticular cation exchange beads and preparation of same

Claim 1

Cation exchange resin beads of macroreticular structure, high surface area, and lowered apparent density crosslinking essentially of a macroreticular crosslinked copolymer matrix with cation exchange functional groups bonded thereto, said resin beads having (1) an apparent density of at least 0.02 density units less than, and (2) a surface area much greater than gel-type ion exchange beads of the same composition, said beads resulting from the presence therein of microscopic channels or voids of much larger dimensions than the micropores of gel-type ion exchange beads of the same composition, and which crosslinked copolymer matrix is prepared by copolymerizing a mixture consisting essentially of (i) a monovinyl carbocyclic aromatic compound or an ester of an acrylic or methacrylic acid, with (ii) a polyethylenically unsaturated monomer selected from the group consisting of a polyvinyl carbocyclic aromatic compound, an ester of a dihydric alcohol and an α-β-ethylenically unsaturated carboxylic acid, diallyl maleate, and divinyl ketone, the copolymerization being conducted while the monomers are dissolved in a phase separating amount of an organic liquid or mixture of organic liquids which is a solvent for said monomers but which is unable to substantially swell the copolymers resulting from copolymerization.