Crosslinking in Acetoacetoxy Functional Waterborne Crosslinkable Latexes

Abstract Chain crosslinking through the different stages of the production of acetoacetoxy ethyl methacrylate (AAEMA) containing acrylic latexes was studied; namely, during the synthesis step, after latex neutralization and after crosslinking with diamines. The gel content of the latex increased with increasing amounts of the functional AAEMA monomer likely due to dimethacrylate impurities contained in the monomer. Moreover, the neutralization of the latex with ammonia had important implications in the microstructure of the polymer. A base catalyzed Michael addition reaction between acetaocetoxy groups and terminal double bonds present in the polymer particles produced chain pre‐crosslinking that affected the further crosslinking reaction with diamines. The compatibility of the diamines with the polymer matrix and the ratio diamine/acetoacetoxy used to crosslink the latex during film formation also played an important role in the crosslinking efficiency as evaluated by solvent resistance of crosslinked films.