New High Performance Two-Component Wood Coatings Comprised of a Hydroxy Functional Acrylic Emulsion and a Water- Dispersible Polyisocyanate

By Sharon Xudong Feng, Mike Dvorchak, Kevan E. Hudson, Christine Renk, Tammy Morgan, Vic Stanislawczyk, Francine Shuster, Dick Todd, Howard Bender, Jim Papenfuss

Statistical methods were used to develop hydroxy functional acrylic emulsions for use with a water-dispersible polyisocyanate crosslinker. The resulting two-component waterborne coating systems were optimized for kitchen cabinet and office furniture applications.

Key performance criteria included appearance and aesthetics, pot life, print and mar resistance, and chemical resistance involving both Kitchen Cabinet Manufacturers’ Association (KCMA) and office furniture requirements.

Statistical analysis revealed several strong correlations between acrylic emulsion hydroxy level, particle size, composition Tg, polymerization process and wood coating performance. For example, smaller acrylic emulsion particle size was found to yield many performance benefits with few detriments. Coating formulation variables were also found to be significant.

Ultimate coating hardness in-creased with water-dispersible polyisocyanate level, yet early hardness readings correlated negatively with water-dispersible polyisocyanate level. Plasticization and crosslinking effects were thought to be responsible.

A higher ethylene glycol monbutyl ether (EB) coalescent level was found to correlate negatively with coating hardness, suggesting a reaction between the EB hydroxyl group and the water-dispersible polyisocyanate, resulting in plasticization of the coating.