Patent ID: 7531611

Claim:
A process for the copolymerization of a fine powder tetrafluoroethylene copolymer, said copolymer containing essentially from 99.70 mol % to 99.99 mol % tetrafluoroethylene monomer units and from 0.01 mol % to 0.30 mol % copolymerized comonomer units having the formula (C n F (2n+1) )CH═CH 2 , wherein 6≦n<10, said process comprising: (a) copolymerizing said monomer and comonomer in a pressurized reactor, (b) initiating said copolymerization by adding potassium permanganate (KMnO 4 ), (c) carrying out the entire reaction in the absence of any ionic strength enhancer, and (d) stopping the addition of (KMnO 4 ) initiator at a point in the reaction no further than 80% of the reaction completion wherein said polymerized comonomer units are present in an amount from 0.01 mol % to 0.30 mol % based upon total copolymer composition, and said copolymer has a raw dispersion primary particle size (RDPS) less than 0.210 microns and has a standard specific gravity (SSG) of less than 2.143.