Vulcanization process using basic zinc carbonate hydroxide

A process for vulcanizing a halogen-containing copolymer of a C4 to C7 isomonoolefin and a para-alkylstyrene, which comprises the step of contacting said copolymer at vulcanization conditions with a vulcanization mixture comprising (a) a zinc compound selected from the group consisting essentially of basic zinc carbonate hydroxides being present in a molar ratio to said halogen-containing copolymer in a range of from about 0,05:1 to about 5:1, and (b) a component selected from the group consisting of a dialkyldithiocarbamate, a diaryldithiocarbamate, an alkyl thiuram sulfide, an aryl thiuram sulfide, a phenolformaldehyde resin, and mixtures thereof.