Production of dispersions of polymers in non-polar liquid media

Dispersions of polymers in non-polar liquids are prepared by forming an emulsion of the polymer in a polar liquid medium with an oil-in-water emulsifier and adding this emulsion slowly to a non-polar liquid medium in the presence of a water-in-oil emulsifier while simultaneously removing the polar liquid medium. Removal of the polar liquid medium can be effected by distillation at atmospheric or reduced pressure. The water-in-oil emulsifier may be added to the initial emulsion before, or at the same time as, the emulsion is added to the non-polar medium. The polar medium is generally water while the non-polar medium may be a petroleum or drying oil. Sodium lauryl sulphate is exemplified as an oil-in-water emulsifier; water-in-oil emulsifiers specified are fatty acid amides, octylphenyl-polyglycol ethers, glyceryl mono- and tri-stearate, and sorbitan monostearate. Pentaerythritol esters of dimeric rosin acids may be added to the nonpolar medium before the addition of the polymer emulsion. In examples, the polymers used are polyethyl acrylate, polystyrene and poly-n-butyl acrylate, which are prepared by polymerizing the corresponding monomers in aqueous emulsion using a thioglycollic acid/hydrogen peroxide catalyst. The polyacrylate dispersions are suitable for use in printing inks.