A method for preparing a fluoropolymer aqueous dispersion, including: step (A) of preparing a fluoropolymer aqueous dispersion comprising a fluoropolymer having at least one selected from the group consisting of SO.sub.2Y and COOR (wherein Y is a halogen, and R is a C1 to C4 alkyl) by emulsion polymerization; step (B) of heating the fluoropolymer aqueous dispersion to 50 C. or higher; and step (C) of contacting the fluoropolymer aqueous dispersion with an ion exchange resin for cation exchange after step (B), thereby providing a purified fluoropolymer aqueous dispersion, the fluoropolymer aqueous dispersion being adjusted to pH 7 or lower from the end of the polymerization in step (A) to the end of step (C).

A method for producing an electrolyte emulsion, the method including: Step (1) in which an ethylenic fluoromonomer and a fluorovinyl compound having an SO.sub.2Z.sup.1 group, wherein Z.sup.1 is a halogen element, are copolymerized at a polymerization temperature of 0 C. or higher and 40 C. or lower to provide a precursor emulsion containing a fluoropolymer electrolyte precursor; and Step (2) in which a basic reactive liquid is added to the precursor emulsion and the fluoropolymer electrolyte precursor is chemically treated, whereby an electrolyte emulsion with a fluoropolymer electrolyte dispersed therein is provided, wherein the electrolyte emulsion has an equivalent weight (EW) of 250 or more and 700 or less.

A method for producing an electrolyte emulsion, the method including: Step (1) in which an ethylenic fluoromonomer and a fluorovinyl compound having an SO.sub.2Z.sup.1 group, wherein Z.sup.1 is a halogen element, are copolymerized at a polymerization temperature of 0 C. or higher and 40 C. or lower to provide a precursor emulsion containing a fluoropolymer electrolyte precursor; and Step (2) in which a basic reactive liquid is added to the precursor emulsion and the fluoropolymer electrolyte precursor is chemically treated, whereby an electrolyte emulsion with a fluoropolymer electrolyte dispersed therein is provided, wherein the electrolyte emulsion has an equivalent weight (EW) of 250 or more and 700 or less.

A method for producing an electrolyte emulsion, the method including: Step (1) in which an ethylenic fluoromonomer and a fluorovinyl compound having an SO.sub.2Z.sup.1 group, wherein Z.sup.1 is a halogen element, are copolymerized at a polymerization temperature of 0 C. or higher and 40 C. or lower to provide a precursor emulsion containing a fluoropolymer electrolyte precursor; and Step (2) in which a basic reactive liquid is added to the precursor emulsion and the fluoropolymer electrolyte precursor is chemically treated, whereby an electrolyte emulsion with a fluoropolymer electrolyte dispersed therein is provided, wherein the electrolyte emulsion has an equivalent weight (EW) of 250 or more and 700 or less.

A process for improving a latex comprising the steps of (a) providing a latex comprising a polymer binder, wherein said polymer binder is formed by polymerization of a monomer mixture comprising one or more ethylenically unsaturated carboxylic acid functional monomer, and (b) passing said latex comprising said polymer binder over a cation exchange resin.

A process for improving a latex comprising the steps of (a) providing a latex comprising a polymer binder, wherein said polymer binder is formed by polymerization of a monomer mixture comprising one or more ethylenically unsaturated carboxylic acid functional monomer, and (b) passing said latex comprising said polymer binder over a cation exchange resin.

A process for improving a latex comprising the steps of (a) providing a latex comprising a polymer binder, wherein said polymer binder is formed by polymerization of a monomer mixture comprising one or more ethylenically unsaturated carboxylic acid functional monomer, and (b) passing said latex comprising said polymer binder over a cation exchange resin.

The present invention relates to a method of manufacturing an ionomer resin, comprising the steps of: (i) adding a poor solvent to a crude ionomer resin solution comprising a (meth)acrylic acid unit (A), a neutralized (meth)acrylic acid unit (B) and an ethylene unit (C) to allow a granular resin with a peak top particle size of from 50 to 700 m to be precipitated; and (ii) washing the precipitated granular resin with a washing solution; wherein the total amount of the unit (A) and the unit (B) is from 6 to 10 mol % based on the entire monomeric units constituting the crude ionomer resin.

The present invention relates to a method of manufacturing an ionomer resin, comprising the steps of: (i) adding a poor solvent to a crude ionomer resin solution comprising a (meth)acrylic acid unit (A), a neutralized (meth)acrylic acid unit (B) and an ethylene unit (C) to allow a granular resin with a peak top particle size of from 50 to 700 m to be precipitated; and (ii) washing the precipitated granular resin with a washing solution; wherein the total amount of the unit (A) and the unit (B) is from 6 to 10 mol % based on the entire monomeric units constituting the crude ionomer resin.

A process for reducing thermally induced discoloration of fluoropolymer resin produced by polymerizing fluoromonomer in an aqueous dispersion medium to form aqueous fluoropolymer dispersion and isolating the fluoropolymer from the aqueous medium to obtain fluoropolymer resin. The process comprises contacting the aqueous fluoropolymer dispersion with sorbent.