Surfactant-free semi-continuous emulsion polymerization process for making submicron sized particles for carrier coatings

摘要

Submicron sized particles of poly(methyl methacrylate) are prepared by a surfactant-free semi-continuous emulsion polymerization process that involves (i) preparing an aqueous phase containing a free radical initiator in water by heating and stirring, (ii) preparing a monomer composition containing at least 80% by weight methyl methacrylate and 1 to 10% by weight of a crosslinking agent, (iii) adding the monomer composition to the aqueous phase to initiate emulsion polymerization of the monomer composition, the adding being done at a rate such that from 0.05% to 5% by weight of the total weight of the monomer composition is added per minute, (iv) continuing heating and stirring following completion of the adding of the monomer composition for an amount of time, and (v) drying and recovering the submicron sized particles of poly(methyl methacrylate). The submicron sized particles of poly(methyl methacrylate are used in forming a coating of carrier particles for a two-component developer composition.