Block copolymers for waterborne coatings—A novel eco-friendly approach for improved coating adhesion to untreated polypropylene based plastics

Over the last two decades significant academic research has been devoted to the development of controlled radical polymerization (CRP) techniques for the synthesis of block copolymers. Widespread industrial application of these valuable synthetic tools has been limited so far, mainly due to the inherent disadvantages of the initial CRP techniques. In recent years substantial improvements were made in the application of CRP in heterogeneous aqueous dispersions and now the time seems right to explore the potentials of block copolymers in waterborne coating applications.This paper will address one of the major challenges that today's coatings industry is facing: obtaining good adhesion of waterborne acrylic binders to very hydrophobic plastic substrates like untreated polypropylene. Current processes and chemistries for adhesion promotion to polypropylene based plastics typically rely on flame treatment and/or the use of costly and environmentally unfriendly chlorinated polyolefins. It will be shown that the use of tailored water-based block copolymers can provide an alternative eco-friendly approach to adhesion promotion.

► Novel block copolymer based emulsion binders were designed via RAFT polymerization.
► Block copolymers provide excellent coating adhesion to untreated PP based plastics.
► Adhesion performance directly related to unique polymer design.
► Block copolymers outperform random copolymers in binder stabilization and adhesion.