ISOCYANATE-FUNCTIONALIZED LATEXES - FILM FORMATION AND TENSILE PROPERTIES

Latexes functionalized with isocyanate groups were prepared by carryin g out the emulsion terpolymerization of dimethyl meta-isopropenyl benz yl isocyanate (TMI(R)) with methyl methacrylate and n-butyl acrylate. The film formation of these latexes and the tensile properties of the resulting latex films were studied. The effect of TMI concentration on the film properties was investigated. The locus of the isocyanate gro ups in the latex particles was controlled by using different polymeriz ation processes. The locus of the functional groups was found to great ly influence the tensile properties of the latex films. Triethyl amine was used as an external catalyst to cure the TMI polymer films. One-c omponent self-curable systems capable of undergoing crosslinking at am bient temperatures were developed by incorporating small amounts of me thacrylic acid into the recipe. These systems exhibited significant im provement in tensile properties upon curing. In addition, the shelf-st ability of these latexes was found to be excellent. (C) 1997 John Wile y & Sons, Inc.