EFFECTS OF CORE-SHELL LATEX MORPHOLOGY ON FILM FORMING BEHAVIOR

A series of core‐and‐shell latex particles were made from methyl methacrylate/butyl acrylate copolymers. All latexes were almost monodisperse in particle size. The polymer hardness was varied by changing the methyl methacrylate/butyl acrylate ratio between the limits of 40/60 and 60/40 parts by weight. The minimum film temperatures(MFTs) of these particles were expected to vary with core and shell characteristics in the following order: soft/hard > medium/medium > hard/soft. In fact, this order was observed only if the shell thickness was greater than a certain minimum value that depends on the diameter of the core polymer. Thinner, softer shells on harder cores may require higher drying temperatures than thicker shells with the same composition because the former are required to deform more to produce void‐free films. Copyright © 1990 John Wiley & Sons, Inc.