Patent ID: 7514483

Claim:
An aqueous dispersion of polytetrafluoroethylene comprising: from 55 to 70 mass % of polytetrafluoroethylene fine particles having an average particle diameter of from 0.1 to 0.5 μm, from 0.0001 to 0.02 mass %, based on polytetrafluoroethylene, of a fluorine-containing carboxylic acid salt represented by the formula (1), from 1 to 20 mass %, based on polytetrafluoroethylene, of a nonionic surfactant represented by the formula (2) and/or the formula (3), and from 0.01 to 0.3 mass %, based on polytetrafluoroethylene, of a fluorine-containing carboxylic acid salt represented by the formula (4); wherein formulas (1)-(4) are: formula (1): R 1 —COOX, wherein R 1 is a C 7 alkyl group having fluorine atoms instead of from 90 to 100% of the hydrogen atoms (which may contain from 1 to 2 ether oxygen atoms), and X is an ammonium ion; formula (2): R 2 —O-A-H, wherein R 2 is a C 8-18 alkyl group, and A is a polyoxyalkylene chain consisting of from 5 to 20 oxyethylene groups and from 0 to 2 oxypropylene groups; formula (3): R 3 —C 6 H 4 —O—B—H, wherein R 3 is a C 4-12 alkyl group, and B is a polyoxyalkylene chain consisting of from 5 to 20 oxyethylene groups; and formula (4): R 4 —COOY, wherein R 4 is a C 4-6 alkyl group having fluorine atoms replacing from 30 to 100% of the hydrogen atoms and which may contain from 1 to 2 ether oxygen atoms, and Y is a cationic group represented by the formula {HO(CH 2 ) n } z N + H 4-z , wherein n is an integer of from 2 to 4, and z is an integer of from 0 to 4.