Low temperature process for the preparation of isopropenyl-alpha, alpha-dimethylbenzyl isocyanate--grafted latexes
AssigneeCytec Technology Corp.
InventorHoward R. Lucas
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Abstract
A process for the preparation of novel grafted latexes having backbones formed from unsaturated monomers and having pendent isocyanate containing sidechains derived from isopropenyl-alpha, alpha- dimethylbenzyl isocyanate or copolymers thereof is described. Grafting latexes is carried out using a free radical redox initiator system in an aqueous medium. Latexes such as polybutadiene, polyvinyl chloride, and polyvinyl chloride-acrylic copolymers are converted to the corresponding isocyanate-functional latexes by the process of the invention. The isocyanate-functional grafted and cografted latexes described are useful in curable compositions.
Claims35
A low temperature process for preparing an isocyanate-functional homografted latex comprising the steps of:
- (A) introducing, into a reaction zone containing an aqueous medium and a graftable latex, a homografting charge comprising:
- (i) isopropenyl-alpha,alpha-dimethylbenzyl isocyanate;
- (ii) a hydroperoxide, and
- (iii) a free radical redox initiator solution in an amount sufficient to decompose the hydroperoxide;
- and
- (B) maintaining the reaction zone at a temperature and for a time sufficient to graft the isopropenyl-alpha, alpha-dimethylbenzyl isocyanate.
A low temperature process for preparing an isocyanate-functional cografted latex comprising the steps of:
- (A) introducing into a reaction zone containing an aqueous medium and a graftable latex, a cografting charge comprising:
- (i) isopropenyl-alpha,alpha-dimethylbenzyl isocyanate;
- (ii) an unsaturated comonomer represented by the formula:
- ##STR10## wherein R.sup.1 is selected from a group consisting of hydrogen and alkyl;
- and
- R.sup.2 is selected from a group consisting of methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, hexoxycarbonyl, 2-ethylhexoxycarbonyl, lauroxycarbonyl, alkyl of 1 to 20 carbon atoms, aryl, aminocarbonyl, acetoxy, and cyano groups;
- (iii) a hydroperoxide, and
- (iv) a free radical redox initiator solution in an amount sufficient to decompose the hydroperoxide;
- and
- (B) maintaining the reaction zone at a temperature and for a time sufficient to cograft the monomers (i) and (ii).
Dependencies are inferred from the claim text.