Waterborne polymers for use in thermoset coatings: A new hydrolysis resistant monomer as a replacement for acetoacetoxyethyl methacrylate
In an effort to obtain waterborne polymers which would yield ambient temperature cured films, we synthesized several acetoacetoxyethyl methacrylate containing copolymers. While cured films could be obtained if the copolymers were used to make films soon after they were synthesized, a decline in film performance was noted which correlated with age of the copolymer solution/dispersion. Accordingly, we set out to synthesize a replacement for the acetoacetoxyethyl methacrylate. We decided on an amide type monomer which was synthesized in three steps from 3-isopropenyl-α,α-dimethylbenzyl isocyanate, with an overall yield of 65–70%. The new monomer did not homopolymerize but was found to copolymerize readily with styrene or n-butylacrylate. Films from polymers containing the new monomers had equal or better properties than films obtained from polymers containing acetoacetoxyethyl methacrylate. Analysis showed that the new monomer did not hydrolyze over a period of one year at ambient temperature.
KeywordsReactivity Ratio HMDA Film Performance Hexamethylene Diamine Dimethylbenzyl
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