Method for producing an aqueous dispersion of fluorine-containing elastomer

A two-stage polymerization process in the absence of reactive fluorine-containing surfactants and with iodine or bromine chain transfer agents reduces polymer adhesion to the container and enhances crosslinking in the production of fluorine-containing elastomer dispersions.

JP2026057552AActive Publication Date: 2026-04-02DAIKIN INDUSTRIES LTD
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Patent Information

Authority / Receiving Office
JP · JP
Patent Type
Applications
Current Assignee / Owner
Filing Date
2025-09-22
Publication Date
2026-04-02

AI Technical Summary

Technical Problem

Existing methods for producing an aqueous dispersion of fluorine-containing elastomers result in excessive adhesion of the polymer to the container used in the polymerization reaction.

Method used

A method involving two stages of polymerization in the absence of fluorine-containing surfactants with functional groups that can react by radical polymerization, using an aqueous medium and a polymerization initiator, followed by dilution of the first aqueous dispersion to prepare a second dispersion, which is then used for the second polymerization in the presence of a chain transfer agent with iodine or bromine atoms.

Benefits of technology

This method effectively suppresses the adhesion of the resulting polymer to the container while improving the crosslinking properties of the fluorine-containing elastomer.

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Abstract

To provide a method for producing an aqueous dispersion of a fluorine-containing elastomer that can suppress the adhesion of the resulting polymer to the container used in the polymerization reaction. [Solution] A method for producing an aqueous dispersion of fluorine-containing elastomer, (1) In a container, in the absence of a fluorine-containing surfactant that substantially does not have functional groups that can react by radical polymerization, and in the presence of an aqueous medium and a polymerization initiator, a first polymerization of a fluorine-containing monomer is carried out to prepare a first aqueous dispersion containing a fluorine-containing polymer. (2) Remove the first aqueous dispersion from the container, dilute the removed first aqueous dispersion 3 to 40 times to prepare the second aqueous dispersion, or The first aqueous dispersion is diluted 3 to 40 times in the container to prepare the second aqueous dispersion, which is then removed from the container. (3) A method for producing a third aqueous dispersion containing a fluorine-containing elastomer is provided, by performing a second polymerization of a fluorine-containing monomer in the same container in which the first polymerization was performed or in a different container from the container in which the first polymerization was performed, in the absence of a fluorine-containing surfactant that substantially does not have a functional group that can react by radical polymerization, and in the presence of a chain transfer agent having an iodine atom or a bromine atom, and at least one selected from the group consisting of monomers that give a crosslinkable group containing an iodine atom, a bromine atom or a cyano group, and a second aqueous dispersion.
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Citation Information

Patent Citations

  • Manufacturing method of fluorine-containing elastomer polymer

    JP2005320501A

  • Method of producing fluorine-containing elastomer, and composition

    JP2021046531A

  • Method of Preparing Fluoroelastomer Capable of Being Vulcanized by Using Peroxide

    US20150344604A1

  • Method for producing vulcanizable fluorine-containing elastomer

    WO2004065436A1

  • Method for manufacturing perfluoroelastomer aqueous dispersion, composition, crosslinkable composition, and crosslinked product

    WO2022107890A1