Importance of film morphology on the performance of thermo-responsive waterborne pressure sensitive adhesives

Abstract

Temperature responsive pressure sensitive adhesives (PSAs) are of interests in many applications due to the possibility of removing strong adhesives by moderate heating. In this work, semicrystalline poly(octadecyl acrylate) obtained by miniemulsion polymerization is used as a key component of the thermal responsiveness. Comparison of the adhesive performance of crystalline hard core-soft shell PSAs with other PSAs of the same overall composition and similar molar mass distributions but prepared by blending soft and hard latexes shows that the arrangement of the phases in the film play a key role in performance of the PSAs. Good adhesive performance and thermal responsiveness is only achieved when the crystalline domains are dispersed in a continuous soft phase containing entangled nanogels. Interestingly, this morphology is achieved with blends, but no with core-shell dispersions. The reasons for this difference are investigated.