The present invention relates to a process for preparing a fluoropolymer in a liquid reaction medium, comprising the following steps: provide a reactor containing a liquid reaction medium comprising water introduce in said reactor ethylene monomers and fluorinated monomers, said fluorinated monomers being selected from tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE) or mixtures thereof, pressurize the reactor, initiate polymerization feeding into said reactor a redox initiator comprising an oxidising agent and a reducing agent, wherein said reducing agent in said redox couple initiator is free from sulphur atoms having an oxidation number of 4 or below, wherein the reaction medium is free of fluorinated surfactants.

The present invention relates to a process for preparing a fluoropolymer in a liquid reaction medium, comprising the following steps: provide a reactor containing a liquid reaction medium comprising water introduce in said reactor ethylene monomers and fluorinated monomers, said fluorinated monomers being selected from tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE) or mixtures thereof, pressurize the reactor, initiate polymerization feeding into said reactor a redox initiator comprising an oxidising agent and a reducing agent, wherein said reducing agent in said redox couple initiator is free from sulphur atoms having an oxidation number of 4 or below, wherein the reaction medium is free of fluorinated surfactants.

The present invention relates to a process for preparing a fluoropolymer in a liquid reaction medium, comprising the following steps: provide a reactor containing a liquid reaction medium comprising water introduce in said reactor ethylene monomers and fluorinated monomers, said fluorinated monomers being selected from tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE) or mixtures thereof, pressurize the reactor, initiate polymerization feeding into said reactor a redox initiator comprising an oxidising agent and a reducing agent, wherein said reducing agent in said redox couple initiator is free from sulphur atoms having an oxidation number of 4 or below, wherein the reaction medium is free of fluorinated surfactants.

To provide a method for producing a fluorinated polymer which does not require an emulsifier as an essential component while an aqueous medium with little environmental burden is used. A method for producing a fluorinated polymer, which comprises polymerizing at least one fluorinated polymer selected from tetrafluoroethylene, chlorotrifluoroethylene and vinylidene fluoride, in an aqueous medium in the presence of a specific polymer having at least one type of units selected from units based on a compound represented by the formula (1) and units based on a compound represented by the formula (2) to produce a fluorinated polymer (provided that when tetrafluoroethylene is polymerized, tetrafluoroethylene is polymerized so that the content of units based on tetrafluoroethylene in the fluorinated polymer becomes less than 99 mass % to all units in the fluorinated polymer):

CXY═CR.sup.1—COO-(L-O).sub.n—R.sup.2  formula (1):

CXY═CR.sup.3—(O).sub.m—CH.sub.2—Z—R.sup.4  formula (2):

To provide a method for producing a fluorinated polymer which does not require an emulsifier as an essential component while an aqueous medium with little environmental burden is used. A method for producing a fluorinated polymer, which comprises polymerizing at least one fluorinated polymer selected from tetrafluoroethylene, chlorotrifluoroethylene and vinylidene fluoride, in an aqueous medium in the presence of a specific polymer having at least one type of units selected from units based on a compound represented by the formula (1) and units based on a compound represented by the formula (2) to produce a fluorinated polymer (provided that when tetrafluoroethylene is polymerized, tetrafluoroethylene is polymerized so that the content of units based on tetrafluoroethylene in the fluorinated polymer becomes less than 99 mass % to all units in the fluorinated polymer):

CXY═CR.sup.1—COO-(L-O).sub.n—R.sup.2  formula (1):

CXY═CR.sup.3—(O).sub.m—CH.sub.2—Z—R.sup.4  formula (2):

A method for producing an iodine-containing compound includes reacting a halogen-containing organic iodine compound and a compound containing a reactive carbon-carbon double bond in the presence of a compound of Formula (21) or Formula (22). Each of R.sup.21, R.sup.23 and R.sup.24 represents a hydrogen atom, an iodine atom, or an organic group having from 1 to 20 carbon atoms; R.sup.22 represents a hydrogen atom, an iodine atom, an organic group having from 1 to 20 carbon atoms, or a boron-containing group; R.sup.25 represents a hydrogen atom, an iodine atom, an organic group having from 1 to 20 carbon atoms, or a silicon-containing group; and each of A.sup.1 and A.sup.2 represents a hydrogen atom, a chlorine atom, a bromine atom, or an iodine atom.

##STR00001##

A method for producing an iodine-containing compound includes reacting a halogen-containing organic iodine compound and a compound containing a reactive carbon-carbon double bond in the presence of a compound of Formula (21) or Formula (22). Each of R.sup.21, R.sup.23 and R.sup.24 represents a hydrogen atom, an iodine atom, or an organic group having from 1 to 20 carbon atoms; R.sup.22 represents a hydrogen atom, an iodine atom, an organic group having from 1 to 20 carbon atoms, or a boron-containing group; R.sup.25 represents a hydrogen atom, an iodine atom, an organic group having from 1 to 20 carbon atoms, or a silicon-containing group; and each of A.sup.1 and A.sup.2 represents a hydrogen atom, a chlorine atom, a bromine atom, or an iodine atom.

##STR00001##

The present invention aims to provide a method of producing a fluoropolymer, especially a fluoropolymer essentially including a tetrafluoroethylene or chlorotrifluoroethylene unit, at a higher polymerization rate with improved efficiency, the method being capable of improving the moldability in extrusion molding and suppressing discoloration. The method of producing a fluoropolymer of the present invention includes producing a fluoropolymer by polymerizing tetrafluoroethylene or chlorotrifluoroethylene in the presence of a peroxydicarbonate. The peroxydicarbonate is represented by the formula:
R—O—C(═O)—O—O—C(═O)—O—R
wherein R's may be the same as or different from each other and individually represent a C4 alkyl group or alkoxy alkyl group.

The present invention aims to provide a method of producing a fluoropolymer, especially a fluoropolymer essentially including a tetrafluoroethylene or chlorotrifluoroethylene unit, at a higher polymerization rate with improved efficiency, the method being capable of improving the moldability in extrusion molding and suppressing discoloration. The method of producing a fluoropolymer of the present invention includes producing a fluoropolymer by polymerizing tetrafluoroethylene or chlorotrifluoroethylene in the presence of a peroxydicarbonate. The peroxydicarbonate is represented by the formula:
R—O—C(═O)—O—O—C(═O)—O—R
wherein R's may be the same as or different from each other and individually represent a C4 alkyl group or alkoxy alkyl group.

The present invention aims to provide a method of producing a fluoropolymer, especially a fluoropolymer essentially including a tetrafluoroethylene or chlorotrifluoroethylene unit, at a higher polymerization rate with improved efficiency, the method being capable of improving the moldability in extrusion molding and suppressing discoloration. The method of producing a fluoropolymer of the present invention includes producing a fluoropolymer by polymerizing tetrafluoroethylene or chlorotrifluoroethylene in the presence of a peroxydicarbonate. The peroxydicarbonate is represented by the formula:
R—O—C(═O)—O—O—C(═O)—O—R
wherein R's may be the same as or different from each other and individually represent a C4 alkyl group or alkoxy alkyl group.