Perfluoroelastomer composition having improved processability

Claim 1

A process for preparation of an uncured perfluoroelastomer composition comprising the steps of A) preparing a perfluoroelastomer having a plurality of carbonyl-containing functional groups selected from the group consisting of carboxyl endgroups, carboxylate endgroups, carboxamide endgroups, and mixtures thereof by copolymerizing a monomer mixture comprising a) a perfluoroolefin monomer, b) a perfluorovinyl ether monomer selected from the group consisting of perfluoro(alkyl vinyl) ethers, perfluoro(alkoxy vinyl) ethers, and mixtures thereof, and c) a cure site monomer at a pressure of from 4-10 MPa, in the presence of a persulfate free radical initiator in a polymerization mixture wherein i) the feed ratio of monomer to initiator is controlled so that the ratio of the radical flux to the polymerization rate, R i /R p , is from about 10 to 50 millimoles per kilogram, and ii) less than 5 mole percent of a sulfite or bisulfite reducing agent, based on the total moles of persulfate initiator and reducing agent, is present in the polymerization mixture; B) isolating said perfluoroelastomer having a plurality of carbonyl-containing functional groups; and C) heating said isolated perfluoroelastomer having a plurality of carbonyl-containing functional groups at a temperature of at least 230° C. for a time sufficient to at least partially decarboxylate the perfluoroelastomer.