Method of making vinyl-silicone copolymers using mercapto functional silicone chain-transfer agents and release coatings made therewith

A method of making silicone-vinyl copolymer which comprising:

• (a) mixing (1) free radically polymerizable monomer mixed, if needed, with sufficient solvent to produce a charge which possesses a net dielectric constant greater than about b 2.5, (2) a mercapto functional silicone compound represented by the formula ##STR20## wherein R.sub.1 are monovalent moieties which can independently be the same or different and are selected from the group consisting of alkyl, aryl, alkaryl, alkoxy, alkylamine, hydroxyl, hydrogen, and fluoroalkyl;
• R.sub.2 can independently be the same or different and are divalent linking groups;
• R.sub.3 are monovalent moieties which can independently be the same or different and are selected from the group consisting of alkyl, aryl, alkaryl, alkoxy, alkylamino, hydroxyl, hydrogen, and fluoroalkyl;
• R.sub.4 can independently be the same or different and are divelent linking groups;
• R.sub.5 are monovalent moieties which can independently be the same or different and are selected from the group consisting of alkyl, aryl, alkaryl, alkoxy, alkylamino, hydroxyl, hydrogen, fluoroalkyl and -ZSH, wherein Z is a divalent linking group;
• R.sub.6 are monovalent moieties which can independently be the same or different and are selected from the group consisting of alkyl, aryl, alkaryl, alkoxy, alkylamino, hydroxyl, fluoroalkyl, hydrogen, and -ZSH wherein Z is a divalent linking group;
• wherein
• x is an integer of 0-3;
• y is an integer of 10 or greater;
• q is an integer of 0-3;
• R.sub.5 comprises 0 to y -ZSH moieties;
• R.sub.6 comprises 0 to y -ZSH moieties;
• and
• wherein at least one of the following is true:
• q is an integer of at least 1;
• x is an integer of at least 1;
• R.sub.5 comprises at least one -ZSH moiety;
• R.sub.6 comprises at least one -ZSH moiety;
• and
• (3) an initiator capable of forming free radicals upon being subjected to a means of initiation wherein said free radicals are capable of abstracting the -ZSH hydrogen atoms of the mercapto functional silicone compound to form mercapto functional silicone free radicals,
• wherein said mercapto functional silicone free radicals are capable of initiating free radical polymerization of said free radically polymerizable monomer to form a graft copolymer or block copolymer represented by the formula ##STR21## wherein G.sub.5 are monovalent moieties which can independently be the same or different selected from the group consisting of alkyl, aryl, alkaryl, alkoxy, alkylamino, fluoroalkyl, hydrogen, and -ZSA;
• A is a vinyl polymeric segment or block consisting essentially of polymerized free radically polymerized monomer;
• G.sub.6 are monovalent moieties which can independently be the same or different selected from the group consisting of alkyl, aryl, alkaryl, alkoxy, alkylamino, fluoroalkyl, hydrogen, and -ZSA;
• G.sub.2 comprises A;
• G.sub.4 comprises A;
• and
• R.sub.1, R.sub.2, R.sub.3, R.sub.4 x, q, y, and Z are as previously defined;
• (b) initiating free-radical polymerization;
• and
• (c) sustaining said free-radical polymerization until said vinyl-silicone copolymer is produced.