Provided is a copolymer consisting essentially of ethylene units, tetrafluoroethylene units, and hexafluoropropylene units, wherein a molar ratio (Et units/TFE units) of the ethylene (Et) units to the tetrafluoroethylene (TFE) units is 52.0/48.0 to 56.0/44.0, and a content of the hexafluoropropylene units is 19.0 to 21.0 mol % based on the total monomer units constituting the copolymer.

The invention relates to polyvinylidene fluoride (PVDF) copolymer compositions that have improved crosslinking efficiency and performance. The PVDF copolymer contains a high level (>14 and preferably greater than 16 wt %) of a fluorinated comonomer, and has a high molecular weight as measured by the melt viscosity at 230° C. and 100 sec−1 of 18 to 40 kpoise. The composition can be effectively cross-linked with a low level radiation (high cross-linking efficiency). The cross-linked composition is useful in high-temperature applications, such as automotive wire and cable, and heat shrink tubing.

The invention relates to polyvinylidene fluoride (PVDF) copolymer compositions that have improved crosslinking efficiency and performance. The PVDF copolymer contains a high level (>14 and preferably greater than 16 wt %) of a fluorinated comonomer, and has a high molecular weight as measured by the melt viscosity at 230° C. and 100 sec−1 of 18 to 40 kpoise. The composition can be effectively cross-linked with a low level radiation (high cross-linking efficiency). The cross-linked composition is useful in high-temperature applications, such as automotive wire and cable, and heat shrink tubing.

Provided is a method for producing a fluorine-containing polymer, comprising polymerizing a fluorine-containing monomer in the presence of a fluorine-free compound (1) represented by general formula (1), a polymerization initiator, and an aqueous medium to produce the fluorine-containing polymer:

CX.sup.1X.sup.2═CX.sup.3—R—Z  General formula (1):

wherein X.sup.1, X.sup.2, and X.sup.3 are each independently H or an alkyl group; R is a single bond or an alkylene group; the total number of carbon atoms of X.sup.1, X.sup.2, X.sup.3, and R is 0 to 5; Z is —SO.sub.3M, —OSO.sub.3M, —P(═O)(OM).sub.2, —OP(O)(OM).sub.2, or —B(OM).sub.2; M is H, a metal atom, NR.sup.1.sub.4, optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium; and R.sup.1 is independently H or an organic group, and any two R.sup.1 may be bonded to each other to form a ring.

Provided is a method for producing a fluorine-containing polymer, comprising polymerizing a fluorine-containing monomer in the presence of a fluorine-free compound (1) represented by general formula (1), a polymerization initiator, and an aqueous medium to produce the fluorine-containing polymer:

CX.sup.1X.sup.2═CX.sup.3—R—Z  General formula (1):

wherein X.sup.1, X.sup.2, and X.sup.3 are each independently H or an alkyl group; R is a single bond or an alkylene group; the total number of carbon atoms of X.sup.1, X.sup.2, X.sup.3, and R is 0 to 5; Z is —SO.sub.3M, —OSO.sub.3M, —P(═O)(OM).sub.2, —OP(O)(OM).sub.2, or —B(OM).sub.2; M is H, a metal atom, NR.sup.1.sub.4, optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium; and R.sup.1 is independently H or an organic group, and any two R.sup.1 may be bonded to each other to form a ring.

A method for producing a fluoropolymer which includes polymerizing a fluoromonomer in an aqueous medium in the presence of a surfactant to provide a fluoropolymer, the surfactant being represented by the general formula (1): CR.sup.1R.sup.2R.sup.4—CR.sup.3R.sup.5—X-A, wherein R.sup.1 to R.sup.5 are each H or a monovalent substituent, with the proviso that at least one of R.sup.1 and R.sup.3 represents a group represented by the general formula: —Y—R.sup.6 and at least one of R.sup.2 and R.sup.5 represents a group represented by the general formula: —X-A or a group represented by the general formula: —Y—R.sup.6; and A is the same or different at each occurrence and is —COOM, —SO.sub.3M, or —OSO.sub.3M. Also disclosed is a surfactant for polymerization represented by the general formula (1), a method for producing a fluoropolymer using the surfactant and a composition including a fluoropolymer and the surfactant.

A method for producing a fluoropolymer which includes polymerizing a fluoromonomer in an aqueous medium in the presence of a surfactant to provide a fluoropolymer, the surfactant being represented by the general formula (1): CR.sup.1R.sup.2R.sup.4—CR.sup.3R.sup.5—X-A, wherein R.sup.1 to R.sup.5 are each H or a monovalent substituent, with the proviso that at least one of R.sup.1 and R.sup.3 represents a group represented by the general formula: —Y—R.sup.6 and at least one of R.sup.2 and R.sup.5 represents a group represented by the general formula: —X-A or a group represented by the general formula: —Y—R.sup.6; and A is the same or different at each occurrence and is —COOM, —SO.sub.3M, or —OSO.sub.3M. Also disclosed is a surfactant for polymerization represented by the general formula (1), a method for producing a fluoropolymer using the surfactant and a composition including a fluoropolymer and the surfactant.

Provided are a composite that can be suitably used as an electrolyte for polymer-based solid-state batteries and is excellent in oxidation resistance and flame retardancy, and various electrochemical devices using such a composite. The composite contains a fluorine-containing copolymer that comprises a tetrafluoroethylene (TFE) unit and a vinylidene fluoride (VdF) unit, and an alkali metal salt, wherein the total content of the TFE unit and the VdF unit in the fluorine-containing copolymer is 1 to 99 mol %, and the composite has a volatile content of 0.1 mass % or less with respect to the entire composite.

Provided are a composite that can be suitably used as an electrolyte for polymer-based solid-state batteries and is excellent in oxidation resistance and flame retardancy, and various electrochemical devices using such a composite. The composite contains a fluorine-containing copolymer that comprises a tetrafluoroethylene (TFE) unit and a vinylidene fluoride (VdF) unit, and an alkali metal salt, wherein the total content of the TFE unit and the VdF unit in the fluorine-containing copolymer is 1 to 99 mol %, and the composite has a volatile content of 0.1 mass % or less with respect to the entire composite.

Provided are a composite that can be suitably used as an electrolyte for polymer-based solid-state batteries and is excellent in oxidation resistance and flame retardancy, and various electrochemical devices using such a composite. The composite contains a fluorine-containing copolymer that comprises a tetrafluoroethylene (TFE) unit and a vinylidene fluoride (VdF) unit, and an alkali metal salt, wherein the total content of the TFE unit and the VdF unit in the fluorine-containing copolymer is 1 to 99 mol %, and the composite has a volatile content of 0.1 mass % or less with respect to the entire composite.