Abstract: This invention relates to the preparation of stable aqueous dispersions of particles of film-forming polymer, the particles comprising at least one pre-formed polymer and at least one polymer formed in situ ("multi-polymer particles").The inadequate stability exhibited by many previously known film-forming systems based on multi-polymer particles, especially in the presence of co-solvents, may be overcome by preparing the particles in the presence of a stabilizing compound which is an amphipathic compound with a hydrophilic-lipophilic balance (HLB) value of at least 8 and whose lipophilic portion comprises at least one ethylenic double bond.The dispersions of this invention are useful as the film-forming components of coating compositions.

Abstract: A process of preparing aqueous dispersions of multi-component film-forming polymer particles, suitable for use in a cathodic electrodeposition process. The disperse particles, which may be thermoplastic or thermosetting, are derived from mixtures of pre-formed polymer and addition polymer formed in situ. The process is carried out at a pH below 10 and in the presence of a selected cationic surface active agent which stabilizes the dispersion below pH 10 but renders it unstable at a pH of 10-11.