Ion exchange resins

Claim 1

In the process of preparing hard, crosslinked, discrete copolymer beads by the free-radical polymerization in an aqueous dispersion of a monomer comprised of a major proportion of (a) monovinyl monomer and a minor proportion of (b) crosslinking monomer having at least two active vinyl groups, wherein the improvement comprises conducting the polymerization reaction at a temperature within the range of about 30° to 95° C. with a modifier in admixture with the aforesaid monomer mixture, the modifier being present in a concentration of from about 0.01 to about 10 millimoles per mole of monomers, in the monomer mixture (a) and (b), said modifier being an organic compound containing allylic unsaturation, said organic compound being capable of moderating rate of polymerization, and wherein the modifier is selected from the group consisting of bicycloheptadiene, dimethyloctatriene, terpenes, 2-methyl styrene, alpha-methyl styrene dimer, limonene, cyclohexadiene, methyl cyclohexadiene, camphene, geraniol, farnesol, 2-norbornene, cyclododecatriene, cyclooctadiene, cyclododecene, allyl benzene and 4-vinyl-1-cyclohexene.