Abstract: A method for producing a fluorinated copolymer solution polymerizing a monomer mixture of a fluoro-olefin (A), a monomer (B) having a crosslinkable group and a monomer (C) having no fluorine atom and no crosslinkable group in the presence of an organic solvent and a compound having two or more piperidyl group represented by the formula (1):

Abstract: Provided is a process for producing a fluorinated copolymer which is capable of providing an ion exchange membrane which can suppress a decrease in current efficiency by impurities in an aqueous alkali chloride solution as a raw material on electrolysis of the alkali chloride aqueous solution. Also provided is a process for producing a fluorinated copolymer that comprises washing a fluorinated copolymer comprising a fluorinated monomer having a carboxylic acid type functional group and a fluorinated olefin, with a washing solvent containing a fluorinated solvent at a temperature of at least 40° C. and at most a boiling point of the washing solvent.

Abstract: A process for producing a fluorinated copolymer includes polymerizing a fluorinated monomer having a carboxylic acid functional group or a sulfonic acid functional group and a fluorinated olefin by a solution polymerization method in a polymerization medium to obtain a mixture containing a fluorinated copolymer, an unreacted monomer and the polymerization medium. The mixture is continuously or intermittently transferred to an evaporation vessel provided with a stirrer and heating the mixture with stirring in the evaporation vessel to evaporate and recover the unreacted monomer and the polymerization medium.

Abstract: To provide a fluorinated copolymer which is capable of providing an ion exchange membrane having little adverse effect due to impurities in an alkali chloride aqueous solution on electrolysis of the alkali chloride aqueous solution. To use a fluorinated copolymer of a fluorinated monomer having a carboxylic acid type functional group with a fluorinated olefin, wherein the proportion of components having a common logarithm (log M) of a molecular weight M being from 2.0 to 3.5 is at most 10 mass % per 100 mass % of components having a common logarithm (log M) of a molecular weight M being at least 2.0, contained in a CClF2CF2CClFH soluble content.

Abstract: To provide a method for producing a fluorinated copolymer solution having good storage stability and having good dryability of a coating film when made into a coating composition. A monomer mixture comprising a fluoro-olefin (A), a monomer (B) having a crosslinkable group and a monomer (C) having no fluorine atom and no crosslinkable group, is polymerized in the presence of an organic solvent and a compound having a piperidyl group represented by the formula (1), wherein the molar ratio of the total molar amount of piperidyl groups contained in the compound having a piperidyl group to the total molar amount of monomers in the monomer mixture, is from 0.00105 to 0.00380: In the formula (1), each of R1, R2, R3 and R4 which are independent of one another, is a hydrogen atom, a methyl group or a hydroxy group, and Y is a hydrogen atom, an oxy radical group, an alkyl group, an alkoxy group, an aryl group or a hydroxy group.

Abstract: To provide a well proppant containing fluororesin-coated particles which has a sufficiently small frictional resistance of the surface, which has sufficient chemical resistance and strength, which can be produced with high productivity, of which proppant particles as a base substrate are hardly corroded, and in which the adhesion between the coating fluororesin and the proppant particles as a base substrate is high, and a method for efficiently recovering hydrocarbons from a hydrocarbon-bearing formation. A well proppant containing fluororesin-coated particles having at least part of the surface of proppant particles coated with a fluororesin (F) having a volume flow rate of from 0.

Abstract: To provide a process by which from a mixture containing a fluorinated copolymer, an unreacted monomer and a polymerization medium, the unreacted monomer and the polymerization medium can efficiently be recovered. A process for producing a fluorinated copolymer, which comprises (I) a step of polymerizing a fluorinated monomer having a carboxylic acid functional group or a sulfonic acid functional group and a fluorinated olefin in a polymerization medium to obtain a mixture containing a fluorinated copolymer, an unreacted monomer and the polymerization medium, and (II) a step of continuously or intermittently transferring the mixture to an evaporation vessel provided with a stirrer and heating it with stirring in the evaporation vessel to evaporate and recover the unreacted monomer and the polymerization medium.

Abstract: To provide a process for producing a fluorinated copolymer which is capable of providing an ion exchange membrane which can suppress a decrease in current efficiency by impurities in an aqueous alkali chloride solution as a raw material on e.g. electrolysis of the alkali chloride aqueous solution. A process for producing a fluorinated copolymer, which comprises a step of washing a fluorinated copolymer of a fluorinated monomer having a carboxylic acid type functional group with a fluorinated olefin, by a washing solvent containing a fluorinated solvent, at a temperature of at least 40° C. and at most a boiling point of the washing solvent.

Abstract: To provide a fluorinated copolymer which is capable of providing an ion exchange membrane having little adverse effect due to impurities in an alkali chloride aqueous solution on electrolysis of the alkali chloride aqueous solution. To use a fluorinated copolymer of a fluorinated monomer having a carboxylic acid type functional group with a fluorinated olefin, wherein the proportion of components having a common logarithm (log M) of a molecular weight M being from 2.0 to 3.5 is at most 10 mass % per 100 mass % of components having a common logarithm (log M) of a molecular weight M being at least 2.0, contained in a CClF2CF2CClFH soluble content.

Abstract: A polymerization medium having small ozone depletion potential and small global warming potential and having a small chain transfer constant is used, to efficiently produce a fluoropolymer having a high molecular weight and having excellent heat resistance, solvent resistance, chemical resistance, etc. A process for producing a fluoropolymer, which comprises polymerizing a fluoromonomer having a carboxylic acid type functional group and a fluoroolefin using a hydrofluorocarbon as a medium, wherein the hydrofluorocarbon as the medium has 4 to 10 carbon atoms and has a ratio (molar basis) of the number of hydrogen atoms/the number of fluorine atoms (H/F ratio) of from 0.05 to 20.

Abstract: A polymerization medium having small ozone depletion potential and small global warming potential and having a small chain transfer constant is used, to efficiently produce a fluoropolymer having a high molecular weight and having excellent heat resistance, solvent resistance, chemical resistance, etc. A process for producing a fluoropolymer, which comprises polymerizing a fluoromonomer having a carboxylic acid type functional group and a fluoroolefin using a hydrofluorocarbon as a medium, wherein the hydrofluorocarbon as the medium has 4 to 10 carbon atoms and has a ratio (molar basis) of the number of hydrogen atoms/the number of fluorine atoms (H/F ratio) of from 0.05 to 20.