Abstract: To provide a modified polytetrafluoroethylene which is excellent in the moldability by paste extrusion and the mechanical property of the molded article. A modified polytetrafluoroethylene fine powder which is a fine powder of a non-melt-moldable modified polytetrafluoroethylene, characterized in that the modified polytetrafluoroethylene comprises units derived from tetrafluoroethylene, units derived from a perfluoroalkyl vinyl ether represented by CF2?CFO—CnF2n+1 (wherein n is an integer of from 1 to 6), and units derived from a perfluoroalkylethylene represented by CH2?CH—CmF2m+1 (wherein m is an integer of from 3 to 6), and that the content of the units derived from the perfluoroalkyl vinyl ether is from 0.1 to 0.25 mass % and the content of the units derived from a perfluoroalkylethylene is from 0.001 to 0.1 mass %, based on all monomer units in the modified polytetrafluoroethylene.

Abstract: To provide a PTFE aqueous dispersion which is excellent in mechanical stability, while being not susceptible to foaming. A polytetrafluoroethylene aqueous dispersion which is characterized by containing from 15 to 70 mass % of PTFE particles having an average primary particle diameter of from 0.1 to 0.5 ?m; from 0.1 to 20,000 ppm, to the PTFE particles, of a fluorinated emulsifier selected from a C4-7 fluorinated carboxylic acid which may have an etheric oxygen atom, and salts of thereof; from 1 to 20 parts by mass, to 100 parts by mass of the PTFE particles, of a nonionic surfactant represented by R1—O-A-H (wherein R1 is a C8-18 alkyl group, and A is a polyoxyalkylene chain); from 0.004 to 0.040 parts by mass, to 100 parts by mass of the PTFE particles, of a polyether polysiloxane copolymer, wherein the polyether chain consists solely of a polyoxypropylene group; and water.

Abstract: To optimize the primary particle size of a modified PTFE fine powder to shorten the sintering time during the extrusion molding. A modified polytetrafluoroethylene fine powder which is a fine powder of a non-melt-processable modified polytetrafluoroethylene comprising units derived from tetrafluoroethylene, units derived from hexafluoropropylene, units derived from a perfluoro(alkyl vinyl ether) represented by CF2?CFO—CnF2n+1 (n is an integer of from 1 to 6) and units derived from a (perfluoalkyl)ethylene represented by CH2?CH—CmF2m+1 (m is an integer of from 3 to 7).

Abstract: To provide a PTFE aqueous dispersion which is excellent in mechanical stability, while being not susceptible to foaming. A polytetrafluoroethylene aqueous dispersion which is characterized by containing from 15 to 70 mass % of PTFE particles having an average primary particle diameter of from 0.1 to 0.5 ?m; from 0.1 to 20,000 ppm, to the PTFE particles, of a fluorinated emulsifier selected from a C4-7 fluorinated carboxylic acid which may have an etheric oxygen atom, and salts of thereof; from 1 to 20 parts by mass, to 100 parts by mass of the PTFE particles, of a nonionic surfactant represented by R1—O-A-H (wherein R1 is a C8-18 alkyl group, and A is a polyoxyalkylene chain); from 0.004 to 0.040 parts by mass, to 100 parts by mass of the PTFE particles, of a polyether polysiloxane copolymer, wherein the polyether chain consists solely of a polyoxypropylene group; and water.

Abstract: To provide a polytetrafluoroethylene aqueous dispersion which is excellent in mechanical stability, while being not susceptible to foaming. The polytetrafluoroethylene aqueous dispersion comprises: 15 to 70 mass % of polytetrafluoroethylene particles having an average primary particle size of 0.1 to 0.5 ?m; 0.1 to 20,000 ppm, to the mass of the polytetrafluoroethylene particles, of a fluorinated emulsifier selected from C4-7 fluorinated carboxylic acids which may have an ether oxygen atom, and salts thereof; 1 to 20 parts by mass, per 100 parts by mass of the PTFE particles, of a nonionic surfactant represented by R1—O-A-H (wherein R1 is a C8-18 alkyl group, and A is a polyoxyalkylene chain); 0.01 to 3.0 parts by mass, per 100 parts by mass of the polytetrafluoroethylene particles, of a compound represented by the formula (2) (wherein R is a C2-4 alkyl group, n is 1 or 2, and each of m1 and m2 is an average repeating number of oxyethylene groups, with (m1+m2) being 1 to 6); and water.

Abstract: To provide a method for producing a tetrafluoroethylene copolymer-containing aqueous dispersion excellent in stability against a mechanical stress.

Abstract: To provide a modified polytetrafluoroethylene which is excellent in the moldability by paste extrusion and the mechanical property of the molded article. A modified polytetrafluoroethylene fine powder which is a fine powder of a non-melt-moldable modified polytetrafluoroethylene, characterized in that the modified polytetrafluoroethylene comprises units derived from tetrafluoroethylene, units derived from a perfluoroalkyl vinyl ether represented by CF2?CFO—CnF2n+1 (wherein n is an integer of from 1 to 6), and units derived from a perfluoroalkylethylene represented by CH2?CH—CmF2m+1 (wherein m is an integer of from 3 to 6), and that the content of the units derived from the perfluoroalkyl vinyl ether is from 0.1 to 0.25 mass % and the content of the units derived from a perfluoroalkylethylene is from 0.001 to 0.1 mass %, based on all monomer units in the modified polytetrafluoroethylene.

Abstract: To optimize the primary particle size of a modified PTFE fine powder to shorten the sintering time during the extrusion molding. A modified polytetrafluoroethylene fine powder which is a fine powder of a non-melt-processable modified polytetrafluoroethylene comprising units derived from tetrafluoroethylene, units derived from hexafluoropropylene, units derived from a perfluoro(alkyl vinyl ether) represented by CF2?CFO—CnF2n+1 (n is an integer of from 1 to 6) and units derived from a (perfluoalkyl)ethylene represented by CH2?CH—CmF2m+1 (m is an integer of from 3 to 7).