Patent ID: 6903175

Claim:
A method of preparing a plurality of cross-linked solution polymer particles comprising the steps of: a) providing a monomer feed comprising one or more ethylenically or acetylenically unsaturated monomers, and one or more multi-ethylenically unsaturated cross-linking agents; b) providing a polymerization initiator feed comprising a polymerization initiator; c) providing a reaction vessel containing one or more reaction solvents; d) heating the one or more reaction solvents to a temperature sufficient to activate the polymerization initiator; and then e) adding the initiator feed and the monomer feed to the reaction vessel at a rate such that the concentration of the one or more monomers in the one or more reaction solvents is substantially constant to provide the cross-linked solution polymer particles having a mean particle size of 0.75 to 100 nm.