Continuous production of specialty waterborne adhesives: Tuning the adhesive performance

The possibility of tuning the adhesive performance of all-acrylic waterborne adhesives produced in a continuous stirred tank reactor (CSTR) was investigated by manipulating the conditions in the holding tank.The effect of the holding tank temperature, the addition of different types of chain transfer agents and the post-polymerization using different initiator systems was investigated. It was observed that the holding tank temperature had a significant effect on polymer architecture, which in turn led to different adhesion performance. The water-solubility of the chain transfer agents, as well as the production time at which the addition was performed were found to be crucial controlling the polymer structure. An early shot at 10% of the total production, combined with a water-soluble CTA led to important changes in polymer structure and therefore on its adhesion performance. Post-polymerization was found to be effective in monomer removal. The choice of the initiator system was another means to modify the polymer structure and hence a possible way to extend the range of properties achievable with the given base emulsion polymer produced in the CSTR.