| US 7,531,611 B2 | ||
| Copolymers of tetrafluoroethylene | ||
| Edward A. Sabol, Newark, Del. (US); and Richard L. Baillie, Newark, Del. (US) | ||
| Assigned to Gore Enterprise Holdings, Inc., Newark, Del. (US) | ||
| Filed on Jul. 05, 2005, as Appl. No. 11/174,882. | ||
| Prior Publication US 2007/0010642 A1, Jan. 11, 2007 | ||
| Int. Cl. C08F 214/26 (2006.01) | ||
| U.S. Cl. 526—250 [526/242; 526/247; 526/253; 428/502] | 13 Claims |
| 1. 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
(CnF(2n+1))CH═CH2,
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 (KMnO4),
(c) carrying out the entire reaction in the absence of any ionic strength enhancer, and
(d) stopping the addition of (KMnO4) 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.
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