Patent ID: 8658733

Claim:
A process for the preparation of monodisperse polymer particles comprising: 1) preparing monodisperse swellable seed particles by emulsion polymerization, wherein an anionic surfactant is employed as emulsifier under substantially oxygen-free conditions; wherein said seed particles are non-oligomeric: (a1) contacting said non-oligomeric seed particles with an aqueous dispersion comprising an organic compound with a molecular weight below 5000 Dalton and a water solubility at 25° C. of less than 10 −2 g/L; the anionic surfactant; and optionally an organic solvent in which said organic compound is soluble; (b1) allowing said organic compound to diffuse into said non-oligomeric seed particles; and (c1) contacting the aqueous dispersion of non-oligomeric seed particles with a monomer which is at least ten times more water soluble than said organic compound; or wherein said seed particles are oligomeric: (a2) contacting said oligomeric seed particles with an aqueous dispersion comprising the anionic surfactant; and (b2) contacting the aqueous dispersion of oligomeric seed particles with a monomer; 2) if required adding a water-soluble steric stabilizer, if required adding a porogen, and if required adding a polymerization initiator; and 3) initiating polymerization of said monomer in an aqueous dispersion containing a steric stabilizer in continuous phase.