| 摘要 |
The present invention relates generally to the use of talc as a chemical foaming agent in perfluoropolymers to form foamable and foamed compositions. For example, in one aspect, a foamable composition is disclosed, which comprises (i) one or more base perfluoropolymers comprising at least 50 percent by weight of the composition, and (ii) talc blended with the one or more base perfluoropolymers, where the talc comprises 3 percent to about 15 percent by weight of the composition. Each of the perfluoropolymers is selected from the group consisting of tetrafluoroethylene/perfluoromethylvinyl ether copolymer (MFA), hexafluoropropylene/tetrafluoroethylene copolymer (FEP) and perfluoroalkoxy (PFA) and any blend thereof, where hydrogen-containing fluoropolymers are absent from the composition. The one or more base perfluoropolymers are melt-processable at one or more elevated processing temperatures of at least about 600° F. at which the talc functions as a chemical foaming agent for extrusion or mold processing of the composition into a foamed article having uniform cell structures. |
