Method for producing melt-processable fluororesin
View Patent ↗To provide a method for producing a melt-processable fluororesin, which is capable of increasing the molecular weight of the fluororesin and preventing coloration of the fluororesin, by using a specific fluorinated emulsifier other than ammonium perfluorooctanoate. A method for producing a melt-processable fluororesin which is characterized in that a fluorinated monomer is emulsion-polymerized in an aqueous medium containing a fluorinated emulsifier of a formula (I) XCF 2 CF 2 (O) m CF 2 CF 2 OCF 2 COOA wherein X is a hydrogen atom or a fluorine atom, A is a hydrogen atom, an alkali metal or NH 4 , and m is an integer of 0 or 1.
1. A method for producing a melt-processable fluororesin, wherein said method comprises emulsion-polymerization of a fluorinated monomer in an aqueous medium comprising a fluorinated emulsifier according to the formula
CF 3 CF 2 OCF 2 CF 2 OCF 2 COONH 4 .
2. The method for producing a melt-processable fluororesin according to claim 1 , wherein the fluorinated monomer is at least one fluorinated monomer selected from the group consisting of tetrafluoroethylene, vinylidene fluoride, hexafluoropropylene, a perfluoro(alkyl vinyl ether) of CF 2 =CFOR f wherein R f is a C 1-16 perfluoroalykyl group which may comprise an etheric oxygen atom, chlorotrifluoroethylene, a polyfluoroalkyl ethylene, perfluoro(2,2-dimethyl-1,3-dioxole), a perfluoro(4-alkyl-1,3-dioxole) and CF 2 =CFO(CF 2 ) n CF=CF 2 wherein n is 1 or 2.
3. The method for producing a melt-processable fluororesin according to claim 1 , wherein the melt-processable fluororesin is a copolymer of ethylene and at least one fluorinated monomer selected from the group consisting of tetrafluoroethylene, vinylidene fluoride, hexafluoropropylene and chlorotrifluoroethylene.
4. The method for producing a melt-processable fluororesin according to claim 1 , wherein the melt-processable fluororesin is a copolymer selected from the group consisting of a tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer, a tetrafluoroethylene/hexafluoropropylene copolymer, a tetrafluoroethylene/ethylene copolymer, a tetrafluoroethylene/hexafluoropropylene/vinylidene fluoride copolymer, a tetrafluoroethylene/hexafluoropropylene/ethylene copolymer, a tetrafluoroethylene/hexafluoropropylene/perfluoro(alkyl vinyl ether) copolymer, a polyvinylidene fluoride and a chlorotrifluoroethylene/ethylene copolymer.
5. The method for producing the melt-processable fluororesin according to claim 1 , wherein the content of the fluorinated emulsifier is 0.01-10 wt. %, based on the total weight of the aqueous medium.