| abstract |
Mixture of tetrafluoroethylene/hexafluoropropylene (TFE/HFP) copolymers comprising 5 to 20% by weight of hexafluoropropylene, the specific melt viscosity at 380 DEG C. of which is from 1x104 to 60x104 poise, (a) the melt flow ratio being at least 3.5, and (b) the zero strength time (ZST, second) at 380 DEG C. satisfying the following equation: ZST>/=1/3x2+17x+107 wherein x is (specific melt viscosity)x10-4 having an improved extrudability, particularly an improved extrusion speed. These mixtures of copolymers contain a high specific melt viscosity portion and a low specific melt viscosity portion. |