Pressure sensitive adhesives with post-crosslinking ability based on acrylic dispersions obtained from solvent-borne copolymers

Abstract This work presents a novel aqueous dispersion prepared from a solvent-borne acrylic copolymer mixture containing carboxylic acid groups for the first copolymer and epoxy groups for the second copolymer. The aim of this work was to test the suitability of the presented dispersion for the preparation of pressure sensitive adhesives (PSA) with post-crosslinking ability. A monomodal particle size distribution was obtained and a successful coemulsification of both copolymers into one particle was proved, although the epoxy containing polymer did not bear carboxylic acid groups. Storage of the dispersion led to intraparticular crosslinking inside the particles, which produced an increase in the shear of the PSA. Post-crosslinking ability was shown for the PSA of the unaged and aged dispersions in the presence of 1-methylimidazole and led to a major increase in shear but did not lead to a considerable decrease in peel. Probe-tack enabled a fast detection of post-crosslinking because of the appearance of a plateau formation in probe-tack curves. The adhesive properties before and after crosslinking demonstrate the potential of the presented dispersion, which yields novel PSA for applications which need high shear but also sufficient peel.