Investigation of Different Emulsion Polymerization Methods for Preparing High Solid Content Latexes

One of the challenges in emulsion polymerization over the past two decades has been how to increase the solid content of polymer latex. Compared to conventional latex, high solid content latex (HSC) has a large volume fraction of the monomer dispersed phase, even more than 70% by weight. Increasing the concentration of polymer in latex, has important advantages such as increasing the space-time efficiency of the reactor, reducing the film formation and drying time, as well as reducing its storage and transportation costs. Conventional emulsion polymerization, mini-emulsion polymerization, self-emulsification polymerization, and concentrated emulsion polymerization have all been used to prepare HSC latexes, and good results have been reported in recent years. Production of HSC latexes in a reproducible manner requires precise control of the particle size distribution. To obtain a solid content above 60% or 70% by weight, the particle size distribution must be quite broad or multimodal. In addition, viscosity of HSC latex is highly sensitive to particle size distribution. In this study, the advances of the last few years, which are mainly in the preparation processes of such latexes and their applications are briefly reviewed.