Provided is a fluoropolymer composition production method for producing a fluoropolymer composition containing a fluoropolymer, the method which includes polymerizing a fluoromonomer in a reactor in the presence of a fluorine-containing surfactant, a polymerization initiator, and an aqueous medium to prepare an aqueous dispersion containing a fluoropolymer; after the aqueous dispersion is prepared, removing from the reactor the fluoromonomer remaining in the reactor, or recovering the aqueous dispersion in the reactor and accommodating the aqueous dispersion in a container different from the reactor; adding a radical generator to the aqueous dispersion; and subjecting to a heat treatment the aqueous dispersion comprising the radical generator to give a fluoropolymer composition.

A method for producing a fluoropolymer aqueous dispersion, including a step A of performing ultrafiltration, microfiltration, or dialysis membrane treatment, or a combination thereof on a pretreatment aqueous dispersion containing a fluoropolymer obtained by polymerization in the presence of a polymer (I) including a polymerized unit (I) derived from a monomer represented by the following general formula (I), with the proviso that the fluoropolymer is other than the polymer (I):

CX.sup.1X.sup.3═CX.sup.2R(—CZ.sup.1Z.sup.2-A.sup.0).sub.m  (I)

wherein X.sup.1 and X.sup.3 are each independently F, Cl, H, or CF.sub.3; X.sup.2 is H, F, an alkyl group, or a fluorine-containing alkyl group; A.sup.0 is an anionic group; R is a linking group; Z.sup.1 and Z.sup.2 are each independently H, F, an alkyl group, or a fluorine-containing alkyl group; and m is an integer of 1 or more.

A method for producing a fluoropolymer aqueous dispersion, including a step A of performing ultrafiltration, microfiltration, or dialysis membrane treatment, or a combination thereof on a pretreatment aqueous dispersion containing a fluoropolymer obtained by polymerization in the presence of a polymer (I) including a polymerized unit (I) derived from a monomer represented by the following general formula (I), with the proviso that the fluoropolymer is other than the polymer (I):

CX.sup.1X.sup.3═CX.sup.2R(—CZ.sup.1Z.sup.2-A.sup.0).sub.m  (I)

wherein X.sup.1 and X.sup.3 are each independently F, Cl, H, or CF.sub.3; X.sup.2 is H, F, an alkyl group, or a fluorine-containing alkyl group; A.sup.0 is an anionic group; R is a linking group; Z.sup.1 and Z.sup.2 are each independently H, F, an alkyl group, or a fluorine-containing alkyl group; and m is an integer of 1 or more.

A method for producing a fluoropolymer aqueous dispersion, including a step A of performing ultrafiltration, microfiltration, or dialysis membrane treatment, or a combination thereof on a pretreatment aqueous dispersion containing a fluoropolymer obtained by polymerization in the presence of a polymer (I) including a polymerized unit (I) derived from a monomer represented by the following general formula (I), with the proviso that the fluoropolymer is other than the polymer (I):

CX.sup.1X.sup.3═CX.sup.2R(—CZ.sup.1Z.sup.2-A.sup.0).sub.m  (I)

wherein X.sup.1 and X.sup.3 are each independently F, Cl, H, or CF.sub.3; X.sup.2 is H, F, an alkyl group, or a fluorine-containing alkyl group; A.sup.0 is an anionic group; R is a linking group; Z.sup.1 and Z.sup.2 are each independently H, F, an alkyl group, or a fluorine-containing alkyl group; and m is an integer of 1 or more.

A method for producing a fluoropolymer aqueous dispersion, including a step A of subjecting a pre-treatment aqueous dispersion containing a fluoropolymer obtained by polymerization in the presence of a hydrocarbon surfactant to ultrafiltration, microfiltration, or dialysis membrane treatment, or a combination thereof The ultrafiltration is performed using an ultrafiltration membrane having a molecular weight cutoff of 0.3×10.sup.4 Da or more.

A method for producing a fluoropolymer aqueous dispersion, including a step A of subjecting a pre-treatment aqueous dispersion containing a fluoropolymer obtained by polymerization in the presence of a hydrocarbon surfactant to ultrafiltration, microfiltration, or dialysis membrane treatment, or a combination thereof The ultrafiltration is performed using an ultrafiltration membrane having a molecular weight cutoff of 0.3×10.sup.4 Da or more.

The invention relates to a process to produce a stable fluoropolymer latex using non-fluorinated surfactant with greater thermal stability. The polymerization is run at pressures greater than typically used. The resulting polymer exhibit improved melt color stability as compared to those produced under similar conditions at lower pressures.

The invention relates to a process to produce a stable fluoropolymer latex using non-fluorinated surfactant with greater thermal stability. The polymerization is run at pressures greater than typically used. The resulting polymer exhibit improved melt color stability as compared to those produced under similar conditions at lower pressures.

A method for producing a polymer solution including a methacrylate copolymer having a weight average molecular weight of not less than 100,000, a weight average molecular weight/number average molecular weight of 1.01 to 1.8 and a glass transition temperature of not more than 40° C. and including methyl methacrylate units and alkyl (meth)acrylate units containing a C10-36 alkyl group, and a first solvent having a boiling point of not less than 200° C., through steps including a step (I) of preparing the methacrylate copolymer by polymerizing monomers in a second solvent having a boiling point of below 200° C., and a step (II) of mixing the solution from the step (I) which includes the methacrylate copolymer and the second solvent, with the first solvent, and removing the second solvent to raise the content of the first solvent to not less than 10 mass % of the polymer solution.

A method for producing a polymer latex, including an emulsification step of emulsifying a polymer solution obtained by dissolution of synthetic polyisoprene and/or a styrene-isoprene-styrene block copolymer having a molecular weight distribution of 1.0 to 2.6 in an organic solvent, in water in the presence of a surfactant, to thereby obtain an emulsified liquid, wherein as the synthetic polyisoprene and/or styrene-isoprene-styrene block copolymer, used are/is synthetic polyisoprene and/or a styrene-isoprene-styrene block copolymer which, when dissolved in an organic solvent to thereby be formed into a polymer solution having a viscosity at a temperature of 60 C. of 20,000 cps, have/has a solid content concentration in the range of 10 to 60% by weight.