Tertiary-alkylperoxy alkyl carbonate initiators for hot air vulcanization of silicone rubber

A method of vulcanizing a silicone rubber composition which comprises:

• a. preparing a heat-vulcanizable composition comprising
• i. 100 parts of organopolysiloxane polymer gum curable to an elastomeric state and represented by the formula ##STR5## wherein:
• R is selected independently from the group consisting of monovalent hydrocarbon groups, monovalent halogenated hydrocarbon groups, and monovalent cyanoalkyl groups, and
• ii. in a minor amount between about 0.1 and 10 parts per 100 parts of organopolysiloxane polymer sufficient to provide complete surface cure, a tertiary-alkylperoxy alkyl carbonate cure initiator represented by the formula ##STR6## wherein:
• R.sub.1 is a tertiary alkyl group having 4 to 14 carbons and
• R.sub.2 is an alkyl group having 8 to 26 carbons;
• b. shaping heat-vulcanizable composition to form an article having a surface;
• and
• c. contacting at least a part of the surface of the article with a heated gas for between about 1 and 120 seconds at a temperature above about 315.degree. C. and at about atmospheric pressure or below in order to cure the article to an elastomeric state and to provide a complete surface cure.