Patent ID: 6794487
Filing Date: 2004-09-21
Classification: B29B,B29K,C08F,Y02P

Abstract:
A method for improving the thermal stability of a fluorine-containing polymer comprising melt kneading a melt-processable fluorine-containing polymer with a kneader which has a residence time of at least 10 minutes, a usable volume ratio based on usable space in a container/space in a container, said usable volume ratio being larger than 0.3, and a power factor K of less than 8000, the power factor K being represented by the formula:K=Pv/&mgr;/n2 wherein Pv is a power requirement per unit volume (W/m3), &mgr; is a melt viscosity (Pa.s), and n is a rotation speed (rps) wherein said fluorine-containing polymer is a copolymer comprising at least two monomers selected from the group consisting of tetrafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ethers, ethylene, vinylidene fluoride and chlorotrifluoroethylene; vinylidene fluoride homopolymer; or chlorotrifluoroethylene homopolymer wherein water or steam is supplied in sufficient amount to remove any unstable end groups.