Patent ID: 7008587

Claim:
A method of improving extrusion properties in an extrudate comprising (i) blending a major amount of a first fluoropolymer, wherein the first fluoropolymer comprises a semi-crystalline fluorinated copolymer, and a minor amount of a second fluoropolymer effective to improve extrusion properties in the blend, and (ii) melt processing the blend to form the extrudate, wherein the first fluoropolymer is selected from class: (a) a semi-crystalline perfluorinated copolymer; (b) a fluoropolymer derived from interpolymerized units of at least one essentially perfluorinated monomer, at least one non-fluorinated hydrogen-containing monomer, and, optionally, perfluorobutyl-ethylene and/or no more than about 1% by weight of other partially fluorinated monomers; and (c) a fluoropolymer derived from interpolymerized units of at least one 5% by weight of at least one partially-fluorinated monomer selected from vinylidene fluoride, vinyl fluoride, and/or tri-fluoroethylene, and optionally at least one essentially perfluorinated monomer; and wherein the second fluoropolymer is selected from class (a); (b); (c); (d) an amorphous copolymer of tetrafluoroethylene and hexafluoropropylene; and (e) an amorphous fluorinated copolymer derived from interpolymerized units of a perfluoro (alkoxy vinyl) ether and a comonomer which may be partially or fully fluorinated; wherein when the first fluoropolymer is selected from (a), the second fluoropolymer is a fluoropolymer selected from at least one material of class (b), a semi-crystalline material of class (c), and/or a material from class (e); when the first fluoropolymer is selected from (b), the second fluoropolymer is selected from (a), (c), (d), and/or (e); and when the first fluoropolymer is a copolymer selected from (c), the second fluoropolymer is selected from (a), (b), (d), and/or (e), with the proviso that, when the blend comprises one or more copolymers selected from (c), the blend comprises either at least about 80% by weight of copolymers selected from (c) or no more than about 5% by weight of copolymers selected from (c).