Production method for fluoropolymer aqueous dispersion
First Claim
1. A method of producing an aqueous dispersion containing at least one fluoropolymer selected from the group consisting of polytetrafluoroethylene and tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymers, the method comprisingpolymerizing a fluoromonomer in an aqueous medium in the presence of a fluorosurfactant having a Log POW value of not higher than 3.4 and a polymerization initiator and at least one of a modifying monomer and a chain-transfer agent,the amount of the fluorosurfactant corresponding to 18000 to 500000 ppm of the aqueous medium,wherein the modifying monomer is at least one selected from the group consisting of hexafluoropropylene, chlorotrifluoroethylene, vinylidene fluoride, perfluoropropyl vinyl ether, perfluorobutylethylene, ethylene, perfluoromethyl vinyl ether, perfluorohexylethylene and a fluorinated vinyl ether represented by the formula CF2═
- CFORf9CN wherein Rf9 represents a C2-C7 alkylene group in which an oxygen atom may optionally be inserted between two carbon atoms,the chain-transfer agent is at least one selected from the group consisting of methane, ethane, propane, butane, chloromethane, dichloromethane, difluoroethane, methanol, ethanol and hydrogen,the amount of the modifying monomer is 0.02-1.49 mol % based on the sum of the amounts of the monomers supplied, andthe amount of the chain-transfer agent is 159-3000 ppm based on the sum of the amounts of the monomers supplied.
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Abstract
The present invention aims to provide a method of producing a fluoropolymer aqueous dispersion having a significantly small particle size and excellent dispersion stability without using a long-chain fluorosurfactant. The present invention relates to a method of producing an aqueous dispersion containing at least one fluoropolymer selected from the group consisting of polytetrafluoroethylene and melt-processible fluororesins excluding polytetrafluoroethylene. The method includes polymerizing a fluoromonomer in an aqueous medium in the presence of a fluorosurfactant having a Log POW value of not higher than 3.4 and a polymerization initiator. The amount of the fluorosurfactant corresponds to 4600 to 500000 ppm of the aqueous medium.
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6 Claims
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1. A method of producing an aqueous dispersion containing at least one fluoropolymer selected from the group consisting of polytetrafluoroethylene and tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymers, the method comprising
polymerizing a fluoromonomer in an aqueous medium in the presence of a fluorosurfactant having a Log POW value of not higher than 3.4 and a polymerization initiator and at least one of a modifying monomer and a chain-transfer agent, the amount of the fluorosurfactant corresponding to 18000 to 500000 ppm of the aqueous medium, wherein the modifying monomer is at least one selected from the group consisting of hexafluoropropylene, chlorotrifluoroethylene, vinylidene fluoride, perfluoropropyl vinyl ether, perfluorobutylethylene, ethylene, perfluoromethyl vinyl ether, perfluorohexylethylene and a fluorinated vinyl ether represented by the formula CF2═ - CFORf9CN wherein Rf9 represents a C2-C7 alkylene group in which an oxygen atom may optionally be inserted between two carbon atoms,
the chain-transfer agent is at least one selected from the group consisting of methane, ethane, propane, butane, chloromethane, dichloromethane, difluoroethane, methanol, ethanol and hydrogen, the amount of the modifying monomer is 0.02-1.49 mol % based on the sum of the amounts of the monomers supplied, and the amount of the chain-transfer agent is 159-3000 ppm based on the sum of the amounts of the monomers supplied. - View Dependent Claims (2, 3, 4, 5, 6)
- CFORf9CN wherein Rf9 represents a C2-C7 alkylene group in which an oxygen atom may optionally be inserted between two carbon atoms,
Specification