A composite containing a fluorine-containing copolymer, an alkali metal salt, and an ionic liquid. The fluorine-containing copolymer essentially contains: a structural unit represented by formula (1): —[CR.sup.1R.sup.2—CR.sup.3R.sup.4]— wherein R.sup.1 to R.sup.4 are each independently H, F, Cl, CF.sub.3, or OR.sup.10, where R.sup.10 is an organic group having 1 to 8 carbon atoms, provided that at least one of R.sup.1 to R.sup.4 is F; and a structural unit represented by formula (2): —[CR.sup.5R.sup.6—CR.sup.7R.sup.8]— wherein R.sup.5 to R.sup.8 are each independently H, F, an alkyl group having 1 to 3 carbon atoms, a functional group containing a heteroatom other than the fluorine atom, or a group containing the functional group. At least one of R.sup.5 to R.sup.8 is a functional group containing a heteroatom other than the fluorine atom or a group containing the functional group, and the composite has a volatile content of 0.1 mass % or less.

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.

A fluororesin material containing a fluororesin. The fluororesin has a carbonyl group, the total number of carbonyl groups is 1 or more and less than 800 per 10.sup.6 main-chain carbon atoms, and the fluororesin contains ethylene unit and tetrafluoroethylene unit. When the fluororesin material is heated at a rate of 10° C./minute, the initial pyrolysis temperature when the mass reduction of the fluororesin material reaches 1% by mass is 390° C. or more.

A fluororesin material containing a fluororesin. The fluororesin has a carbonyl group, the total number of carbonyl groups is 1 or more and less than 800 per 10.sup.6 main-chain carbon atoms, and the fluororesin contains ethylene unit and tetrafluoroethylene unit. When the fluororesin material is heated at a rate of 10° C./minute, the initial pyrolysis temperature when the mass reduction of the fluororesin material reaches 1% by mass is 390° C. or more.

The present invention provides 1,3,3,3-tetrafluoropropene (HFO-1234ze) copolymers comprising 1,3,3,3-tetrafluoropropene and one or more comonomers selected from the group consisting of vinyl fluoride (VF), vinylidene fluoride (VF.sub.2), tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), and perfluoro(alkyl vinyl ether) (PAVE), wherein said alkyl contains 1 to 5 carbon atoms, the copolymers being a fluoroplastic or a fluoroelastomer, depending upon monomer content.

A film containing a resin composition containing an aromatic polyetherketone resin (I) and a fluorine-containing copolymer (II). The fluorine-containing copolymer (II) defines a dispersed phase at an average dispersed particle size of 5 .Math.m or smaller. The aromatic polyetherketone resin (I) has a crystallinity of lower than 6%.

Tetrafluoroethene-based fluoropolymers of low gel content, methods of making the fluoropolymers, methods of extruding the fluoropolymers into articles, and extruded articles comprising the fluoropolymers.

A method for producing a binder composition for a storage battery device, which comprises an emulsion polymerization step of emulsion polymerizing a monomer mixture containing a fluorinated vinyl monomer in the presence of a first anionic emulsifying agent (A), an aqueous medium and a radical polymerization initiator to obtain a latex containing a fluorinated polymer, and a post addition step of adding a second anionic emulsifying agent (B) to the latex. The first anionic emulsifying agent (A) has no phenyl group in its molecule, and the second anionic emulsifying agent (B) has a phenyl group in its molecule.

A method for producing a fluoropolymer by solution polymerization or dispersion polymerization, the method including: in the presence of an initiator, a chain transfer agent, and a solvent, (i) homopolymerizing tetrafluoroethylene; or (ii) randomly copolymerizing tetrafluoroethylene and at least one of a monomer represented by the following formula (1) or a monomer represented by the following formula (2). The chain transfer agent includes at least one selected from dithioester compounds, dithiocarbamate compounds, trithiocarbonate compounds and xanthate compounds. The fluoropolymer contains 50 to 100 mol % of a polymerized unit based on the tetrafluoroethylene. The formula (1): CF.sub.2═CR.sup.1R.sup.2 wherein R.sup.1 and R.sup.2 are as defined herein, the formula (2): CH.sub.2═CR.sup.3R.sup.4 wherein R.sup.3 and R.sup.4 are as defined herein.

A method for producing a fluoropolymer by solution polymerization or dispersion polymerization, the method including: in the presence of an initiator, a chain transfer agent, and a solvent, (i) homopolymerizing tetrafluoroethylene; or (ii) randomly copolymerizing tetrafluoroethylene and at least one of a monomer represented by the following formula (1) or a monomer represented by the following formula (2). The chain transfer agent includes at least one selected from dithioester compounds, dithiocarbamate compounds, trithiocarbonate compounds and xanthate compounds. The fluoropolymer contains 50 to 100 mol % of a polymerized unit based on the tetrafluoroethylene. The formula (1): CF.sub.2═CR.sup.1R.sup.2 wherein R.sup.1 and R.sup.2 are as defined herein, the formula (2): CH.sub.2═CR.sup.3R.sup.4 wherein R.sup.3 and R.sup.4 are as defined herein.