Process for controlling molecular weight distribution of latex polymers

Claim 1

A process for controlling the particle morphology and molecular weight distribution of emulsion polymerized latex polymers, said process comprising introducing at least one primary polymerizable ethylenically unsaturated monomers feed composition containing from 0 to 5 weight percent of a chain transfer agent and from 0 to 5 weight percent of at least one crosslinking agent from at least one primary feed source to a polymerization zone, said primary polymerizable ethylenically unsaturated monomers feed composition continually varying in compositional content by the simultaneous addition thereto during its introduction to the polymerization zone, from at least one secondary feed source, of at least one secondary polymerizable ethylenically unsaturated monomers feed composition containing from 0 to 5 weight percent of a chain transfer agent and from 0 to 5 weight percent of at least one crosslinking agent so as to continually change the compositional content of the primary polymerizable ethylenically unsaturated monomers feed composition in said primary feed source during the addition thereto of said secondary polymerizable ethylenically unsaturated monomers feed composition, and simultaneously polymerizing the primary polymerizable ethylenically unsaturated monomers feed composition introduced to the polymerization zone whereby emulsion polymerized latex polymer of broadened molecular weight distribution is produced; with the proviso that there be a positive amount of said chain transfer agent in at least one of said feed compositions during at least a portion of the polymerization period.