In situ synthesis and properties of hydrogenated rosin/polyacrylate composite miniemulsions-based pressure sensitive adhesives

Abstract

Hydrogenated rosin/polyacrylate composite miniemulsions-based pressure sensitive adhesives were synthesized by in situ miniemulsion polymerization method. The effect of HR amount on the monomer conversion rate, particle size and its polydispersity, coagulum rate, Zeta potential, and stability of the composite miniemulsions were studied, the effect of HR and crosslinker amount on the adhesion properties of the composite latex films were also investigated, and the composites were characterized by differential scanning calorimetry (DSC) and gel permeation chromatograph. The results showed that with HR amount increasing, the monomer conversion rate decreased, and the absolute value of Zeta potential and the molecular weight of the sol in the composite latex films also decreased, while the particle size and its polydispersity were almost unaffected. DSC analysis indicated that HR had relative good compatibility with polyacrylate. However, excess HR amount led to the decrease of the centrifugal stability and storage stability of the composite miniemulsions. Furthermore, with HR amount increasing, the ball tack of the latex films increased gradually, 180o peel strength first increased and then decreased, and holding force decreased constantly. When HR amount exceeded 10 wt%, the failure style changed from interface failure to cohesion failure. The crosslinker CX-100 was helpful for the improvement of 180o peel strength and holding force. When HR and CX-100 amount were 10 and 0.6 wt%, the ball tack, 180o peel strength, and holding force were 9 #, 8.9 N/25 mm, and 178 h, respectively.