Method for stabilizing fluorine-containing polymer
AssigneeDaikin Industries, Ltd.
InventorsYoshiyuki Hiraga, Tomohisa Noda, Hiroyuki Imanishi, Satoshi Komatsu
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Abstract
A melt-processable fluorine-containing polymer is melt kneaded with a kneader which has a residence time of at least 10 minutes, a usable volume ratio (usable space in a container/space in a container) of larger than 0.3, and a power factor K of less than 8000, the power factor K being represented by the formula: K=Pv/μ/n2 in which Pv is a power requirement per unit volume (W/m3), μ is a melt viscosity (Pa.s), and n is a rotation speed (rps), to effectively remove terminal groups and bonds in the backbones, which are unstable during melt kneading, from the melt-processable fluorine-containing polymer, and obtain a colorless fluorine-containing polymer.
Claims5
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/μ/n2
- wherein Pv is a power requirement per unit volume (W/m3), μ 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
- a pure fluorine gas or a diluted fluorine gas is supplied into the kneader to remove any unstable end groups.
Dependencies are inferred from the claim text.