Synthesis and Characterization of Large Particle Size Self-Matting Core-shell Acrylic Resin

Acrylic resin plays an important role in leather-making, such as finishing agent, filler and tanning agent. Acrylic resin can be easily fabricated via conventional emulsion polymerization, but how to prepare large particle size with self-matting effect has always been a challenge. In this paper, a continuous three-stage polymerization method: seed-polymerization coupled core-polymerization and shell polymerization was employed to prepare large particle size self-matting acrylic resin emulsion. Simultaneously, the effect of feeding methods on particles size and the effects of latex particle size, shell structure and cross-linking degree on the morphology and gloss of coating were investigated. The Z-average size of PBA seed latex particles was 213.4 nm for semi-continuous feeding method but 82.3nm for batch feeding method. After three-time continuous growth, the seed emulsion turned into core emulsion, and the particle size of core latex reached about 700nm. In third stages of shell polymerization, the core emulsion was changed into core-shell emulsion, and the latex particle size increased further to 804nm. The latex particle size, core-shell structure and cross-linking degree of shell layer were found to influence the gloss of the coating. Large latex particle size imparted the film spherical micro-rough surface, soft-core combined with hard-shell structure led to deformation resistant during film formation and cross-linking of shell layer increased the densification of shell layer, all contributed to the coating rough surface, as a result, increasing the matting effect of the coating. Finally, the leather gloss was reduced from 5.8 degrees to 1.2 degrees.