Abstract: The present invention relates to a process for synthesizing a particulate copolymer comprising: providing a reaction mixture comprising a reaction medium, a polymerization stabilizer, a water-insoluble ethylenically unsaturated monomer and an ethylenically unsaturated monomer containing hydrophilic functionality, said reaction mixture having a viscosity value of at least 10 cps measured at 40° C., and polymerizing the water-insoluble ethylenically unsaturated monomer and the ethylenically unsaturated monomer containing hydrophilic functionality. The polymerization reaction is preferably conducted at a temperature lower than 100° C. and activated by a polymerization catalyst. The resulting particulate copolymer dispersion comprises copolymer particles showing a weight average diameter size in the range of microns and absence of defects, such as coagulant or agglomerates.