Polymer dispersions

A process for the production of a stable dispersion of particles of a copolymer selected from the group consisting of copolyester, copolyamide and copolyesteramide in an inert organic liquid medium in which the copolymer is insoluble by the copolymerization of two or more reactive comonomers each of which is capable of undergoing homopolymerization and each of which is solid at the temperature at which the copolymerization reaction takes place and is insoluble in the liquid medium at that temperature, the process comprising the steps of (1) dispersing the solid comonomers in an inert organic liquid in the presence of at least one monomerstabilizing agent so as to produce stably dispersed particles of the comonomers having a mean diameter not greater than 50.mu., each monomer-stabilizing agent being per se soluble in the inert organic liquid and incorporating (i) a polymeric component which is solvatable by the liquid and (ii) a grouping which is capable of becoming associated with the particles of solid comonomer and (2) heating the dispersion of solid comonomers at the copolymerization temperature so as to bring about the copolymerization reaction, in the presence of a copolymerstabilizing agent which is per se soluble in the inert organic liquid and incorporated (a) a polymeric component which is solvatable by the liquid and (b) a grouping which is capable of effecting association with the resulting copolymer as the copolymer is formed.