Patent ID: 8466214

Claim:
A process for making a core of a core-shell copolymer comprising the steps of: a) emulsion polymerizing in the presence of a radical polymerization initiator a polymerization mixture comprising i) one or more monomers comprising at least one ethylenic elastomeric monomer, ii) at least one crosslinking agent and iii) at least one sulfur-comprising additive of formula (I): wherein: R is —CH 2 R 1 , —CHR 1 R′ 1 or —CR 1 R′ 1 R″ 1 , where R 1 , R′ 1 and R″ 1 , may be the same or different, and each are independently selected from optionally substituted saturated or unsaturated alkyl groups, optionally substituted aromatic carbocyclic or heterocyclic groups, optionally substituted alkylthio groups, optionally substituted alkoxy groups, optionally substituted dialkylamino groups, organometallic groups, acyl groups, acyloxy groups, carboxylic acid group or salts thereof, carboxylic acid ester groups, sulfonic acid groups or salts thereof, sulfonic acid ester groups, alkoxycarbonyl or aryloxycarbonyl groups or polymer groups; and Z is selected from hydrogen, halogen atoms, optionally substituted alkyl groups, optionally substituted aryl groups, optionally substituted heterocyclic groups, optionally substituted —SR 2 groups, optionally substituted alkoxycarbonyl groups, optionally substituted aryloxycarbonyl groups, —COOH, —OCOR 2 , optionally substituted carbamoyl groups of formula —CONHR 2 or —CONR 2 R 3 , —CN, —P(═O)OR 2 2 groups, —P(═O)R 2 2 groups, polymer groups, —OR 2 groups or —NR 2 R 3 groups; where R 2 and R 3 , may be the same or different, and are independently selected from C 1 to C 18 alkyl groups, C 2 to C 18 alkenyl groups, C 6 to C 18 aryl groups, heterocyclic groups, aralkyl groups and alkaryl groups, where each of these groups may optionally be substituted by at least one substituent selected from epoxy groups, hydroxyl groups, alkoxy groups, acyl groups, acyloxy groups, carboxyl groups or salts thereof, carboxylic acid ester groups, sulfonic acid groups or salts thereof, sulfonic acid ester groups, alkoxycarbonyl or aryloxycarbonyl groups, isocyanato groups, cyano groups, silyl groups, halogen atoms or dialkylamino groups; and where the crosslinking agent is selected from divinylbenzene, trivinylbenzene, vinyl acrylate, allyl methacrylate, vinyl methacrylate, butadienediol diacrylate, hexanecliol diacrylate, PEG diacrylate, trimethylolpropane trimethacrylate or mixtures thereof, and b) forming crosslinked elastomeric core particles.