Patent ID: 8436054
Filing Date: 2013-05-07
Classification: C08F

Abstract:
1. A process for making an aqueous dispersion of fluorinated ionomer particles comprising first and second polymerization steps: polymerizing in said first polymerization step at least one fluorinated monomer having an ionic group in an aqueous polymerization medium in the presence of initiator, said polymerizing providing dispersed solid particulate of fluorinated ionomer; suspending said first polymerization step prior to beginning said second polymerization step so that fluorinated ionomer formed in the second polymerization step does not incorporate significant quantities of residual monomer from the first polymerization step; and polymerizing in said second polymerization step at least one fluorinated monomer having an ionic group in an aqueous polymerization medium in the presence of said solid dispersed particulate of fluorinated ionomer and initiator to form the aqueous dispersion of particles of fluorinated ionomer.