Fluororesin composition and electric wire
A fluororesin composition including a tetrafluoroethylene/hexafluoropropylene-based copolymer and 0.01 to 3 parts by mass per 100 parts the copolymer of a polytetrafluoroethylene having a standard specific gravity of 2.15 to 2.30, and being obtained by mixing an aqueous dispersion of the tetrafluoroethylene/hexafluoropropylene-based copolymer with an aqueous dispersion of the polytetrafluoroethylene, causing coagulation, drying the polymer mixture and melt-extruding the same.
1. A fluororesin composition comprising a tetrafluoroethylene/hexafluoropropylene-based copolymer and 0.01 to 3 parts by mass per 100 parts said copolymer of a polytetrafluoroethylene having a standard specific gravity of 2.15 to 2.30, and
being obtained by mixing an aqueous dispersion of said tetrafluoroethylene/hexafluoropropylene-based copolymer with an aqueous dispersion of said polytetrafluoroethylene, causing coagulation, drying the polymer mixture and melt-extruding the same,
which shows a die swell ratio of 5 to 35% and a melt tension of 0.08 to 0.16 N.
2. The fluororesin composition according to claim 1 ,
wherein the polytetrafluoroethylene having a standard specific gravity of 2.15 to 2.30 has an average primary particle diameter of 50 to 800 nm.
3. The fluororesin composition according to claim 1 ,
which shows a complex viscosity of 2.5×10 3 to 4.0×10 3 Pa·s and a storage elastic modulus of 0.25 to 3.5 Pa in melt viscoelasticity measurements at 310° C. and at an angular frequency of 0.01 rad/second.
4. The fluororesin composition according to claim 1 , which has a sodium element content of 5 to 100 ppm.
5. An electric wire comprising a core conductor and a covering formed around said core conductor using a fluororesin composition,
said fluororesin composition being the fluororesin composition according to claim 1 .
6. The electric wire according to claim 5 ,
wherein the covering is formed by extrusion covering molding at a running speed of 1000 to 3000 feet/minute and has a process capability index [Cp] in wire diameter fluctuation measurements of not lower than 1.0.
7. The electric wire according to claim 5 ,
wherein the covering is formed by extrusion covering molding at a running speed of 1000 to 3000 feet/minute, and has a process capability index [Cp] in capacitance measurements of not lower than 1.0.
8. The electric wire according to claim 5 ,
wherein the covering is one formed by 20 hours of continuous extrusion covering molding at a running speed of 1000 to 3000 feet/minute,
wherein said covering has or is free of lumps 10 to 50 mils in height, the total number of said lumps being not larger than 100.
9. A foamed electric wire comprising a core conductor and a covering formed around said core conductor using a fluororesin composition,
said fluororesin composition being the fluororesin composition according to claim 1 .