Miniemulsification by catastrophic phase inversion

Abstract

We present an alternative method for the preparation of high solids content, water-borne latex products from a combination of catastrophic phase inversion (CPI) and miniemulsification. Miniemulsions are commonly prepared by the direct emulsification of a monomer in water and subsequent miniemulsification using a high-shear technique. Herein high solid content dispersions of up to 80w/w% solids content monomer-in-water emulsions are prepared by catastrophic phase inversion followed by miniemulsification with a rotor-stator mixer. The subsequent miniemulsification of these monomer-in-water emulsions proves to be almost four times more energy efficient than is possible with direct miniemulsification using the same mixers and recipes. The highly concentrated miniemulsions thus obtained can be successfully diluted to different solid contents for polymerisation, without compromising the droplet size distribution, and used to produce colloidally stable latexes.