SURFACE REACTIVE ACETAL FUNCTIONAL WATERBORNE CORE-SHELL PARTICLES

Core-shell particles were prepared using a two-stage emulsion polymeri zation of styrene and ethyl acrylate. The particle surfaces were modif ied by introducing an acetal functionality, suitable for acid-catalyze d crosslinking processes. Surface functionalization was performed in t wo principally different ways: In the first method, 4-aminobutyraldehy de dimethylacetal was used for grafting through transesterification of ethyl acrylate residues at the surface or through reactions with epox y groups introduced in the second-stage polymerization. In the second method, 4-acrylamidobutyraldehyde dimethylacetal was used as a comonom er to ethyl acrylate in the second-stage polymerization. The reactive particles were used as crosslinking agents in an acid-curing coating s ystem. (C) 1995 John Wiley & Sons, Inc.