摘要:
A copolymer comprising 0.005 to 1.5 mole % of repeating units derived from an iodine-containing fluorinated vinyl ether, 40 to 90 mole % of repeating units derived from vinylidene fluoride, 3 to 35 mole % of repeating units derived from perfluoro(methyl vinyl ether), optionally up to 25 mole % of repeating units derived from hexafluoropropylene and optionally up to 40 mole % of repeating units derived from tetrafluoroethylene, which is obtained by polymerizing the above monomers in the presence of a diiodide compound, contains iodine atoms introduced in the copolymer from the diiodide compound and the iodine-containing fluorinated vinyl ether in amounts of 0.01 to 1 wt. % and 0.01 to 2 wt. %, respectively, and has a Mooney viscosity of 20 to 150.
摘要:
A process for preparing a fluorine-containing polymer through emulsion polymerization method which enhances productivity while maintaining excellent physical properties of the fluorine-containing polymer and comprises (a) a first polymerization step for emulsion-polymerizing a fluorine-containing monomer or a mixture of a fluorine-containing monomer and a non-fluorine-containing monomer in an aqueous medium in the presence of a radical polymerization initiator and an emulsifying agent, (b) a dilution step for diluting the obtained aqueous emulsion of polymer particles with water to reduce the number of emulsified polymer particles per unit amount of aqueous medium in the emulsion and a concentration of emulsifying agent, and (c) a second polymerization step for emulsion-polymerizing a fluorine-containing monomer and/or a non-fluorine-containing monomer in the obtained diluted emulsified solution.
摘要:
The present invention provides a method of producing a fluoroelastomer excellent in dispersion stability at low cost, at a high rate of polymerization and in high yields. The present invention is a method of producing a fluoroelastomer comprising an emulsion polymerization of a fluorinated monomer in the presence of a water-soluble radical polymerization initiator, wherein the emulsion polymerization is carried out in the presence of a compound (1) containing a functional group reactive in radical polymerization and a hydrophilic group and a fluorinated compound (2) containing a fluorocarbon group comprising 1 to 6 continuously united carbon atom with fluorine atom directly bound to each of them as well as a hydrophilic group.
摘要:
The present invention provides a method of producing a fluoroelastomer excellent in dispersion stability at low cost, at a high rate of polymerization and in high yields.The present invention is a method of producing a fluoroelastomer comprising an emulsion polymerization of a fluorinated monomer in the presence of a water-soluble radical polymerization initiator, wherein the emulsion polymerization is carried out in the presence of a compound (1) containing a functional group reactive in radical polymerization and a hydrophilic group and a fluorinated compound (2) containing a fluorocarbon group comprising 1 to 6 continuously united carbon atom with fluorine atom directly bound to each of them as well as a hydrophilic group.
摘要:
A fluorine-containing elastomeric copolymer comprising 55 to 62 mole % of repeating units derived from tetrafluoroethylene and 38 to 45 mole % of repeating units derived from perfluoro(methyl vinyl ether) which is obtained by radically polymerizing the monomers in the presence of a diiodide compound of the formula: RI.sub.2 in which R is a saturated fluorohydrocarbon or chlorofluorohydrocarbon group having 1 to 16 carbon atoms, or a hydrocarbon group having 1 to 3 carbon atoms and which has a Mooney viscosity (ML.sub.1+10 100.degree. C.) in the range between 20 and 150. This copolymer has an excellent compression set at high temperature, which is an important property for sealing members.
摘要:
A process for preparing a fluorine-containing polymer which includes a first step for preparing a dispersion of fluorine-containing emulsified particles (A) having ionic functional groups where a fluorine-containing monomer mixture (i) is polymerized by using a water soluble radical polymerization initiator (a) without addition of an emulsifying agent, and a second step for preparing a fluorine-containing polymer (b) having a small amount of ionic functional groups where fluorine-containing monomers (ii) are emulsion-polymerized by using a radical polymerization initiator (b) in the presence of the fluorine-containing emulsified particles (A) having ionic functional groups without addition of an emulsifying agent.
摘要:
According to the present invention, it is possible to provide a molding material, for example, a sealing material for semiconductor-related production apparatuses which comprises a fluorine-containing multi-segment polymer being excellent in mechanical properties (particularly at high temperature), abrasion resistance and transparency and ensuring reduced contamination and reduced gas permeation while maintaining inherent characteristics of a fluorine-containing elastomer such as flexibility, elasticity, sealing property, chemical resistance and heat resistance. A molding material comprising a fluorine-containing multi-segment polymer having an elastomeric fluorine-containing polymer chain segment and a non-elastomeric fluorine-containing polymer chain segment, in which the elastomeric fluorine-containing polymer chain segment imparts flexibility to the whole polymer and has perhaloolefin units as a recurring unit in an amount of not less than 95% by mole.
摘要:
The present invention provides a method for producing a fluoroelastomer using an emulsifier which is inexpensive and hardly remains in product polymers. The present invention is related to a method for producing a fluoroelastomer, wherein vinylidene fluoride and at least one fluoroolefin monomer other than vinylidene fluoride are copolymerized in the manner of an emulsion polymerization in the presence of an emulsifier represented by C5F11COOM, wherein M represents H, NH4 or an alkali metal.
摘要:
The fluorine-containing polymer having a small number of ionic functional groups is prepared by a process, in which emulsion polymerization proceeds stably and produced polymer does not adhere to side walls of a polymerization reactor even without using an emulsifying agent, and the process comprises a first step for preparing a dispersion comprising fluorine-containing emulsified particles having ionic functional groups by polymerizing a fluorine-containing monomer mixture comprising a perhalo ethylenic monomer and a nonperhalo ethylenic monomer by using a water soluble radical polymerization initiator without adding an emulsifying agent, and a second step for preparing a fluorine-containing polymer having ionic functional groups in a small amount by emulsion polymerization of fluorine-containing monomers using a radical polymerization initiator in the presence of the fluorine-containing emulsified particles having ionic functional groups without adding an emulsifying agent, wherein the fluorine-containing emulsified particles having ionic functional groups prepared in the first step are used in an amount of from 0.01 to 5.0% by mass based on the fluorine-containing polymer to be obtained in the second step, and an amount of the water soluble radical polymerization initiator used in the first step is from 0.01 to 1,000% by mass based on the fluorine-containing emulsified particles having ionic functional groups prepared in the first step.
摘要:
To provide a method of reducing contents of metal components of a fluorine-containing elastomer through preparation thereof and a molded article obtained from the fluorine-containing elastomer having sufficiently reduced contents of metal components. The method of reducing a metal content of the fluorine-containing elastomer through preparation thereof without using a metal oxide, in which among materials excluding a gaseous monomer which are used for polymerization of a fluorine-containing monomer, coagulation and drying, at least one of them contains substantially no metal component, and the fluorine-containing elastomer which has a metal content of not more than 50 ppm and is obtained by that method.