Radical emulsion polymerisation of ethylenic monomers in presence of N-oxyl radicals

摘要

A radical-initiated emulsion polymerisation method for the preparation of an aqueous polymer dispersion, containing at least one compound with an ethylenic unsaturated group emulsified in an aqueous medium using a dispersant, is carried out using a radical polymerisation initiator in the presence of a stabil N-oxyl radical. The initiator is a (hydro)peroxide and/or azo compound which has a molar solubility in water at 25 deg C and a bar which is greater than or equal to the corresponding molar solubility of tert-butyl hydroperoxide in water, and which has a degradation temperature less than 100 deg C in the polymerisation medium. The polymerisation step is carried out at a temperature greater than 100 deg C at a pressure greater than the vapour pressure of the polymer mixture present in the polymerisation vessel. Also claimed are aqueous polymer dispersions prepared by this method.