Patent ID: 8278366

Claim:
A method for manufacturing a foamed article comprising: extruding a foamable composition, which comprises one or more base perfluoropolymers and talc blended with said one or more base perfluoropolymers, said talc comprising 3 percent to about 15 percent by weight of said composition, at a temperature of at least about 600° F. at which the talc functions as a chemical foaming agent so as to form a foamed article, wherein said one or more perfluoropolymers comprises at least about 50 percent by weight of said composition, wherein each of said perfluoropolymers is selected from the group consisting of tetrafluoroethylene/perfluoroethylvinyl ether copolymer (MFA), hexafluoropropylene/tetrafluoroethylene copolymer (FEP), perfluoroalkoxy (PFA) and any blend thereof, wherein, hydrogen-containing fluoropolymers are absent from the composition and said talc is the only chemical foaming agent in said foamable composition, and wherein said extruding step is performed without gas injection.