Patent ID: 6960638

Claim:
A suspension copolymer, comprising: in copolymerized form the following components (a), (b) and (c): (a) more than 1% by weight of a derivative of an unsaturated carboxylic acid of the formula (I), wherein R 1 =H or CH 3 , and R 2 =methyl, ethyl; (b) more than 1% by weight of a derivative of an unsaturated carboxylic acid of the formula (II), wherein R 3 =H or CH 3 , and R 4 =n-butyl, isobutyl; and (c) from 0-15% of one or more monomers copolymerizable with the monomers (a) or (b); said copolymer containing a residual amount of from 1-10% by weight of at least one polymerization initiator selected from the group consisting of peroxides and peroxide mixtures; wherein a sum of the amounts of (a), (b), (c) and said polymerization initiator is 100%; wherein said copolymer is in the form of beads; and wherein said polymerization initiator is homogeneously distributed in said beads.