摘要:
The present invention aims to provide a method of producing a PTFE aqueous dispersion which contains PTFE particles having a small particle size and which is excellent in dispersion stability by multistage polymerization without using a long-chain fluorosurfactant. The method includes the steps of: (1) polymerizing a fluoromonomer in an aqueous medium in the presence of a fluorosurfactant and a polymerization initiator to provide an aqueous dispersion containing particles of at least one fluoropolymer selected from the group consisting of PTFE and melt-processible fluororesins excluding polytetrafluoroethylene; and (2) polymerizing TFE alone or TFE and a modifying monomer in an aqueous medium in the presence of the fluoropolymer particles and a polymerization initiator to provide an aqueous dispersion containing PTFE particles. The fluoropolymer particles have an equivalent weight (EW) of 6,000 or more and a volume average particle size of not smaller than 0.1 nm but smaller than 20 nm.
摘要:
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.
摘要:
The present invention provides a polytetrafluoroethylene aqueous dispersion containing high-molecular-weight, significantly small polytetrafluoroethylene particles and having excellent dispersion stability. The present invention relates to an aqueous dispersion containing polytetrafluoroethylene particles containing a tetrafluoroethylene unit alone or a tetrafluoroethylene unit and a modifying monomer unit based on a modifying monomer copolymerizable with the tetrafluoroethylene. The polytetrafluoroethylene particles have a volume average particle size of not smaller than 0.1 nm but smaller than 20 nm, a melt flow rate of not lower than 0 g/10 min but lower than 80 g/10 min determined at 380°C and 5 kg load, a melting point of 324°C to 360°C, and an initial pyrolysis temperature of not lower than 400°C.
摘要:
The present invention aims to provide a method of producing a PTFE aqueous dispersion which contains PTFE particles having a small particle size and which is excellent in dispersion stability by multistage polymerization without using a long-chain fluorosurfactant. The method includes the steps of: (1) polymerizing a fluoromonomer in an aqueous medium in the presence of a fluorosurfactant and a polymerization initiator to provide an aqueous dispersion containing particles of at least one fluoropolymer selected from the group consisting of PTFE and melt-processible fluororesins excluding polytetrafluoroethylene; and (2) polymerizing TFE alone or TFE and a modifying monomer in an aqueous medium in the presence of the fluoropolymer particles and a polymerization initiator to provide an aqueous dispersion containing PTFE particles. The fluoropolymer particles have an equivalent weight (EW) of 6,000 or more and a volume average particle size of not smaller than 0.1 nm but smaller than 20 nm.
摘要:
The present invention aims to provide a polytetrafluoroethylene aqueous dispersion which contains significantly minute polytetrafluoroethylene particles and which is excellent in dispersion stability, and a significantly minute polytetrafluoroethylene fine powder. The polytetrafluoroethylene aqueous dispersion contains polytetrafluoroethylene particles including a tetrafluoroethylene unit alone or a tetrafluoroethylene unit and a modifying monomer unit derived from a modifying monomer copolymerizable with the tetrafluoroethylene unit. The polytetrafluoroethylene particles have a volume average particle size of not smaller than 0.1 nm but smaller than 20 nm.
摘要:
The present invention provides a method for producing a fluoropolymer aqueous dispersion having a significantly small particle size and excellent dispersion stability. The present invention relates to a method for producing an aqueous dispersion containing at least one fluoropolymer selected from the group consisting of polytetrafluoroethylene and melt-fabricable fluororesins excluding polytetrafluoroethylene. The method includes polymerizing a fluoromonomer in an aqueous medium in the presence of a fluorosurfactant and a polymerization initiator. The fluorosurfactant has a concentration in the aqueous medium of not lower than 0.8 times the critical micelle concentration of the fluorosurfactant.