Fluorine-containing composition, varnish and insulated wire containing this fluorine-containing composition

Abstract

To provide a fluorine-containing composition having both high flexibility and a low dielectric constant. A fluorine-containing composition comprising: a fluorine-containing compound; and a bifunctional crosslinking agent, wherein the fluorine-containing compound includes: constituent unit A containing a 3- to 12-membered cyclic structure in a main skeleton and having a structure in which 50% or more of hydrogen atoms in the cyclic structure are substituted with fluorine atoms; constituent unit B containing a benzene ring in a main skeleton and having a structure in which fluorine atoms account for 30% or less of the number of atoms in the constituent unit; and constituent unit C having an olefinic carbon-carbon double bond or a carbon-carbon triple bond; wherein the fluorine-containing compound contains constituent units A through C produced by bonding constituent unit C at a terminal, and amount of the bifunctional crosslinking agent is greater than 30% by mass to less than 70% by mass, based on the total of the fluorine-containing compound and the bifunctional crosslinking agent being 100% by mass.

Description

TITLE OF THE INVENTION FLUORINE-CONTAINING COMPOSITION, VARNISH AND INSULATED WIRE CONTAINING THIS FLUORINE-CONTAINING COMPOSITIONCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of Japanese Patent Application No. 2023-124367 filed July 31 , 2023, and Japanese Patent Application No. 2024-064618 filed April 12, 2024, the disclosures of which are incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present invention relates to a fluorine-containing composition. More specifically, the present invention relates to a fluorine- containing composition useful for an insulating film and a flexible copper- clad laminate, a varnish containing this fluorine-containing composition, and an insulated wire including the insulating film.CONVENTIONAL TECHNOLOGY

[0003] Insulated wires with a resin insulation coating on the outer surface of the linear metal conductor are used in coils for electrical and electronic equipment such as high-speed switching elements, inverter motors, and transformers. Insulating films are produced by extrusion coating with thermoplastic resin, baking after coating with thermosetting resin varnish, or a combination of these methods.This manner of insulating film must have a high degree of insulation, high adhesion to metal conductors, and flexibility to withstand processing such as bending and stretching.

[0004] As an example of a material for forming insulating films by extrusion coating, Patent Document 1 discloses a composition containing polyarylene sulfide resin and a fluororesin, and Patent Document 2 discloses a composition containing a resin having a specific dielectric constant and a fluororesin.

[0005] Polyimide, polyamideimide, polyesterimide, and the like are known as materials that form insulating films composed of resin varnish,and fluorinated polyimide is disclosed as an example containing fluorine atoms (Patent Document 3).

[0006] Other applications requiring flexibility and insulation include flexible copper-clad laminates. Flexible copper-clad laminates consist of copper foil bonded to one or both sides of a flexible insulating film via an adhesive layer. Polyimide resin is often used as the base material for the insulating film.

[0007] On the other hand, the applicant has proposed a fluororesin with a specific structure as a material exhibiting low dielectric constant and low dielectric loss (Patent Documents 4 and 5). Although these exhibit superior physical properties, the flexibility of cured products thereof has not been tested.PRIOR ART DOCUMENTSPatent Documents

[0008] Patent Document 1 : Japanese Unexamined Patent Application 2023-64193

[0009] Patent Document 2: International Patent Publication No.2014 / 112405

[0010] Patent Document 3: International Patent Publication No.2015 / 002278

[0011] Patent Document 4: Japanese Unexamined Patent Application2022-89150

[0012] Patent Document 5: Japanese Unexamined Patent Application2023-65203SUMMARY OF THE INVENTIONPROBLEM TO BE SOLVED BY THE INVENTION

[0013] The demand for high flexibility and low dielectric constant in insulating films and copper clad laminates is increasing year by year, and further improvement is required.

[0014] The present invention solves the issue of providing a fluorine- containing composition that has both high flexibility and a low dielectric constant.MEANS FOR SOLVING THE PROBLEM

[0015] The inventors achieved the present invention after diligent study of the issue described above and finding that a cured material with both a low dielectric constant and superior flexibility can be obtained by adding a specific amount of a specific crosslinking agent to a specific fluorine- containing compound.

[0016] The present invention provides a fluorine-containing composition comprising: a fluorine-containing compound; and a bifunctional crosslinking agent, wherein the fluorine-containing compound includes: constituent unit A containing a 3- to 12-membered cyclic structure in a main skeleton and having a structure in which 50% or more of hydrogen atoms in the cyclic structure are substituted with fluorine atoms; constituent unit B containing a benzene ring in a main skeleton and having a structure in which fluorine atoms account for 30% or less of the number of atoms in the constituent unit; and constituent unit C having an olefinic carbon-carbon double bond or a carbon-carbon triple bond; wherein the fluorine-containing compound contains constituent units A through C produced by bonding in the order of C-B-(A-B)n-C or C-A-(B-A)n- C (where n is a value greater than 1 and less than 30), and amount of the bifunctional crosslinking agent is greater than 30% by mass to less than 70% by mass, based on the total of the fluorine-containing compound and the bifunctional crosslinking agent being 100% by mass.

[0017] In the fluorine-containing composition of the present invention:[1] the fluorine-containing compound preferably has the structure of formula (I);Chem. Fig. 1in the formula, L represents a structure of the following Formula (II) or (III).Chem. Fig. 2R1and R2each independently represent a group selected from a group consisting of hydrogen atoms, C1 to C10 alkyl groups, C1 to C10 haloalkyl groups, and C6 to C10 aryl groups, or R1and R2may be combined together to form a ring structure that may include substitution groups,R3and R4each independently represent a group selected from a group consisting of a hydrogen atom, a fluorine atom, C1 to C10 saturated or unsaturated hydrocarbon groups in which some or all hydrogens may be substituted by a halogen, and C6 to C10 aryl groups in which some or all hydrogens may be substituted by a halogen, n is in a range of greater than 1 and less than 30, andX represents a group containing an olefinic carbon-carbon double bond or a carbon-carbon triple bond.

[0018] Furthermore, in the fluorine-containing composition of the present invention:[2] X includes at least 1 fluorine atom, L is selected from a group consisting of cyclopentylidene groups that may have a substitution group, cyclohexylidene groups that may have a substitution group, and cyclododecylidene groups that may have a substitution group; and[3] the fluorine-containing compound has the following structure;Chem. Fig. 3in the formula, n is greater than 1 and less than 30.[4] The bifunctional crosslinking agent preferably does not contain a fluorine atom.

[0019] The present invention also provides a varnish containing the fluorine-containing composition and a solvent.

[0020] The present invention also provides an insulated electrical wire, including: a conductor; and an insulating film, wherein the insulating film is composed of the fluorine-containing composition.EFFECT OF THE INVENTION

[0021] The present invention can provide a cured product with superior flexibility and a low dielectric constant. In addition, the present invention can provide a varnish for easy coating with the cured product described above. Furthermore, the present invention can provide an insulated electrical wire with an insulation film having superior flexibility and a low dielectric constant.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a schematic diagram depicting a flexibility evaluation performed using a steel rod on the embodiment.

[0023] FIG. 2 is a schematic diagram depicting a flexibility evaluation performed on the embodiment with the steel rod removed.MODE FOR CARRYING OUT THE INVENTIONFluorine-containing compositions

[0024] The fluorine-containing composition of the present invention being a composition including a fluorine-containing compound and a bifunctional crosslinking agent is a first important feature, and the content of the bifunctional crosslinking agent exceeding 30% by mass and being less than 70% by mass with regard to the total of the fluorine-containing compound and the bifunctional crosslinking agent being 100% by mass is a second important feature.

[0025] In other words, as is clear from the results of the embodiment described below, while superior flexibility is exhibited by the composition of the present invention, if the bifunctional crosslinking agent is replaced by a trifunctional or tetrafunctional crosslinking agent, or if a bifunctional crosslinking agent is used outside the content range described above, a cured product with superior flexibility cannot be obtained.

[0026] The amount of the bifunctional crosslinking agent is more preferably 35% by mass or more to 65% by mass or less, and even more preferably 40% by mass or more to 60% by mass or less.Fluorine-containing compound

[0027] The fluorine-containing compound of the present invention provides a fluorine-containing compound, containing: constituent unit A containing a 3 - to 12-membered cyclic structure in a main backbone and having a structure in which 50% or more of hydrogen atoms in the cyclic structure are substituted with fluorine atoms; constituent unit B containing a benzene ring in a main backbone and having a structure in which fluorine atoms account for 30% or less of the number of atoms in the constituent unit; and constituent unit C having an olefinic carbon-carbon double bondor a carbon-carbon triple bond; wherein the function of each of the constituent units A to C can be provided by the fluorine-containing compound.

[0028] In other words, the compound has excellent electrical properties (low dielectric constant) and flame retardancy provided by constituent unit A, excellent solvent solubility and high glass transition temperature provided by constituent unit B, and excellent reactivity provided by constituent unit C, which is located at the end of the compound, thus enabling the compound to have excellent thermosetting properties.

[0029] Furthermore, in the fluorine-containing compound that constitutes the fluorine-containing composition of the present invention, constituent units A to C are preferably bonded in the order of C-B-(A-B)n- C- • -(i) or C-A-(B-A)n-O • -(ii). Thus, a cured product with a high gel fraction (crosslinking density) can be obtained.

[0030] In the formulas (i) and (ii) described above, the value of n is preferably larger than 1 and less than 30, more preferably 2 or more and 20 or less, and even more preferably 5 or more and 10 or less.

[0031] In the fluorine-containing compound described above, n represents the average degree of polymerization. The average degree of polymerization can be predicted from the stoichiometric ratio of the monomers and can also be measured by a conventionally known method such as nuclear magnetic resonance spectroscopy and the like. In the present invention, "n is 1" means that the average degree of polymerization of the compound is 0.5 to 1 .4. In the present invention, n is sometimes expressed as an integer, but n can similarly be a distribution.Constituent Unit A

[0032] The constituent unit A that is included in the fluorine-containing compound has a structure containing a 3- to 12-membered cyclic structure in a main backbone, where 50% or more of the hydrogen atoms in the cyclic structure are substituted with fluorine atoms. The excellent electrical properties and flame retardancy of fluorine can be provided to the fluorine- containing compound by having 50% or more, suitably 100%, of thehydrogen atoms in the cyclic structure of the constituent unit A substituted with fluorine atoms.

[0033] The 3- to 12-membered cyclic structure in the constituent unit A can have three or more ring structures in the main backbone, but one or two may be provided in the main backbone, and having one to three ring structures including the side chains is preferable. The elements constituting the cyclic structure are not particularly limited, and include carbon, nitrogen, oxygen, sulfur, and silicon atoms, and the like.

[0034] Specific examples of the constituent unit A include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cyclopropene, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclononene, cyclodecene, cyclobutadiene, cyclopentadiene, cyclohexadiene, cycloheptadiene, cyclooctadiene, cyclononadiene, cyclodecadiene, cycloheptatriene, cyclooctatri ene, cyclododecatriene, benzene, biphenyl, terphenyl, pentalene, indene, naphthalene, azulene, heptalene, indane, acenaphthylene, fluorene, spirofluorene, benzofluorene, dibenzofluorene, phenalene, phenanthrene, anthracene, fluoranthene, triphenylene, pyrene, chrysene, naphthacene, picene, perylene, pentaphene, hexacene, pentacene, rubicene, coronene, ovalene, pyrrole, thiophene, furan, imidazole, pyrazole, thiazole, isothiazole, oxazole, isoxazole, pyridine, pyrazine, pyrimidine, pyridazine, isoindoline, indoline, indazoline, purine, quinoline, isoquinoline, benzoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, galvazole, phenanthridine, acridine, phenanthroline, phenazine, benzimidazole, benzofuran, benzothiophene, isobenzothiazole, benzoxazole, isobenzoxazole, triazole, tetrazole, oxadiazole, triazine, dibenzofuran, dibenzothiophene, benzocarbazole, dibenzocarbazole, thiadiazole, imidazopyridine, and the like, which may each have a substitution group.

[0035] When a plurality of 3- to 12-membered cyclic structures are included in the constituent unit A, the ring structures can be the same or different structures.

[0036] Examples of substitution groups include the following substitution groups.

[0037] Fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, hydroxyl groups, cyano groups, nitro groups, amino groups, amidino groups, hydrazine groups, hydrazone groups, carboxylic acid groups or salts thereof, sulfonic acid groups or salts thereof, phosphoric acid groups or salts thereof, C1 to C60 alkyl groups, C2 to C60 alkenyl groups, C2 to C60 alkynyl groups, and C1 to C60 alkoxy groups;

[0038] C1 to C60 alkyl groups, C2 to C60 alkenyl groups, C2 to C60 alkynyl groups and C1 - C60 alkoxy groups substituted with at least one substitution group selected from a group consisting of fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, hydroxyl groups, cyano groups, nitro groups, amino groups, amidino groups, hydrazine groups, hydrazone groups, carboxylic acid groups or salts thereof, sulfonic acid groups or salts thereof, phosphoric acid groups or salts thereof, cyclopentyl groups, cyclohexyl groups, cycloheptyl groups, cyclopentenyl groups, cyclohexenyl groups, phenyl groups, biphenyl groups, terphenyl groups, pentalenyl groups, indenyl groups, naphthyl groups, azulenyl groups, heptalenyl groups, indanyl groups, acenaphthyl groups, fluorenyl groups, spiro-fluorenyl groups, benzofluorenyl groups, dibenzofluorenyl groups, phenalenyl groups, phenanthrenyl groups, anthracenyl groups, fluoranthenyl groups, triphenylenyl groups, pyrenyl groups, chrysenyl groups, naphthacenyl groups, picenyl groups, perylenyl groups, pentaphenyl groups, hexacenyl groups, pentacenyl groups, rubicenyl groups, coronenyl groups, obarenyl groups, pyrrolyl groups, thiophenyl groups, furanyl groups, imidazolyl groups, pyrazolyl groups, thiazolyl groups, isothiazolyl groups, oxazolyl groups, isoxazolyl groups, pyridinyl groups, pyrazinyl groups, pyrimidinyl groups, pyridazinyl groups, isoindolyl groups, indolyl groups, indazolyl groups, purinyl groups,

[0039] quinolinyl groups, isoquinolinyl groups, benzoquinolinyl groups, phthalazinyl groups, naphthyridinyl groups, quinoxalinyl groups,quinazolinyl groups, cinnolinyl groups, carbazolyl groups, phenanthridinyl groups, acridinyl groups, phenanthrolinyl groups, phenazinyl groups, benzimidazolyl groups, benzofuranyl groups, benzothiophenyl groups, isobenzothiazolyl groups, benzoxazolyl groups, isobenzoxazolyl groups, triazolyl groups, tetrazolyl groups, oxadiazolyl groups, triazinyl groups, dibenzofuranyl groups, dibenzothiophenyl groups, benzocarbazolyl groups, dibenzocarbazolyl groups, thiadiazolyl groups, imidazopyridinyl groups, and imidazopyrimidinyl groups;

[0040] cyclopentyl groups, cyclohexyl groups, cycloheptyl groups, cyclopentenyl groups, cyclohexenyl groups, phenyl groups, biphenyl groups, terphenyl groups, pentalenyl groups, indenyl groups, naphthyl groups, azulenyl groups, heptalenyl groups, indanyl groups, acenaphthyl groups, fluorenyl groups, spiro-fluorenyl groups, benzofluorenyl groups, dibenzofluorenyl groups, phenalenyl groups, phenanthrenyl groups, anthracenyl groups, fluoranthenyl groups, triphenylenyl groups, pyrenyl groups, chrysenyl groups, naphthacenyl groups, picenyl groups, perylenyl groups, pentaphenyl groups, hexacenyl groups, pentacenyl groups, rubicenyl groups, coronenyl groups, obarenyl groups, pyrrolyl groups, thiophenyl groups, furanyl groups, imidazolyl groups, pyrazolyl groups, thiazolyl groups, isothiazolyl groups, oxazolyl groups, isoxazolyl groups, pyridinyl groups, pyrazinyl groups, pyrimidinyl groups, pyridazinyl groups, isoindolyl groups, indolyl groups, indazolyl groups, purinyl groups, quinolinyl groups, isoquinolinyl groups, benzoquinolinyl groups, phthalazinyl groups, naphthyridinyl groups, quinoxalinyl groups, quinazolinyl groups, cinnolinyl groups, carbazolyl groups, phenanthridinyl groups, acridinyl groups, phenanthrolinyl groups, phenazinyl groups, benzimidazolyl groups, benzofuranyl groups, benzothiophenyl groups, isobenzothiazolyl groups, benzoxazolyl groups, isobenzoxazolyl groups, triazolyl groups, tetrazolyl groups, oxadiazolyl groups, triazinyl groups, dibenzofuranyl groups, dibenzothiophenyl groups, benzocarbazolyl groups, dibenzocarbazolyl groups, thiadiazolyl groups, imidazopyridinyl groups, and imidazopyrimidinyl groups;cyclopentyl groups, cyclohexyl groups, cycloheptyl groups, cyclopentenyl groups, cyclohexenyl groups, phenyl groups, biphenyl groups, terphenyl groups, pentalenyl groups, indenyl groups, naphthyl groups, azulenyl groups, heptalenyl groups, indanyl groups, acenaphthyl groups, fluorenyl groups, spiro-fluorenyl groups, benzofluorenyl groups, dibenzofluorenyl groups, phenalenyl groups, phenanthrenyl groups, anthracenyl groups, fluoranthenyl groups, triphenylenyl groups, pyrenyl groups, chrysenyl groups, naphthacenyl groups, picenyl groups, perylenyl groups, pentaphenyl groups, hexacenyl groups, pentacenyl groups, rubicenyl groups, coronenyl groups, obarenyl groups, pyrrolyl groups, thiophenyl groups, furanyl groups, imidazolyl groups, pyrazolyl groups, thiazolyl groups, isothiazolyl groups, oxazolyl groups, isoxazolyl groups, pyridinyl groups, pyrazinyl groups, pyrimidinyl groups, pyridazinyl groups, isoindolyl groups, indolyl groups, indazolyl groups, purinyl groups, quinolinyl groups, isoquinolinyl groups, benzoquinolinyl groups, phthalazinyl groups, naphthyridinyl groups, quinoxalinyl groups, quinazolinyl groups, cinnolinyl groups, carbazolyl groups, phenanthridinyl groups, acridinyl groups, phenanthrolinyl groups, phenazinyl groups, benzimidazolyl groups, benzofuranyl groups, benzothiophenyl groups, isobenzothiazolyl groups, benzoxazolyl groups, isobenzoxazolyl groups, triazolyl groups, tetrazolyl groups, oxadiazolyl groups, triazinyl groups, dibenzofuranyl groups, dibenzothiophenyl groups, benzocarbazolyl groups, dibenzocarbazolyl groups, thiadiazolyl groups, imidazopyridinyl groups, and imidazopyrimidinyl groups, any of which may be substituted with at least one substitution group selected from a group consisting of fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, hydroxyl groups, cyano groups, nitro groups, amino groups, amidino groups, hydrazine groups, hydrazone groups, carboxylic acid groups or salts thereof, sulfonic acid groups or salts thereof, phosphoric acid groups or salts thereof, C1 to C60 alkyl groups, C2 to C60 alkenyl groups, C2 to C60 alkynyl groups, C1 to C60 alkoxy groups, cyclopentyl groups, cyclohexyl groups, cycloheptyl groups, cyclopentenyl groups, cyclohexenyl groups, phenyl groups, biphenyl groups, terphenyl groups, pentalenyl groups, indenyl groups, naphthyl groups, azulenyl groups, heptalenyl groups, indanyl groups,acenaphthyl groups, fluorenyl groups, spiro-fluorenyl groups, benzofluorenyl groups, dibenzofluorenyl groups, phenalenyl groups, phenanthrenyl groups, anthracenyl groups, fluoranthenyl groups, triphenylenyl groups, pyrenyl groups, chrysenyl groups, naphthacenyl groups, picenyl groups, perylenyl groups, pentaphenyl groups, hexacenyl groups, pentacenyl groups, rubicenyl groups, coronenyl groups, obarenyl groups, pyrrolyl groups, thiophenyl groups, furanyl groups, imidazolyl groups, pyrazolyl groups, thiazolyl groups, isothiazolyl groups, oxazolyl groups, isoxazolyl groups, pyridinyl groups, pyrazinyl groups, pyrimidinyl groups, pyridazinyl groups, isoindolyl groups, indolyl groups, indazolyl groups, purinyl groups, quinolinyl groups, isoquinolinyl groups, benzoquinolinyl groups, phthalazinyl groups, naphthyridinyl groups, quinoxalinyl groups, quinazolinyl groups, cinnolinyl groups, carbazolyl groups, phenanthridinyl groups, acridinyl groups, phenanthrolinyl groups, phenazinyl groups, benzimidazolyl groups, benzofuranyl groups, benzothiophenyl groups, isobenzothiazolyl groups, benzoxazolyl groups, isobenzoxazolyl groups, triazolyl groups, tetrazolyl groups, oxadiazolyl groups, triazinyl groups, dibenzofuranyl groups, dibenzothiophenyl groups, benzocarbazolyl groups, dibenzocarbazolyl groups, thiadiazolyl groups, imidazopyridinyl groups, and imidazopyrimidinyl groups; and the like.

[0041] A plurality of substitution groups may be present, in which case the substitution groups may be the same or different

[0042] Constituent unit A preferably contains a benzene ring or cyclopentenyl group. More preferably examples include benzene, which may have a substitution group; cyclopentenyl groups, which may have a substitution group; compounds with a benzene ring bonded to another aromatic ring, such as biphenyl, terphenyl, and the like, which may have a substitution group; and compounds with a benzene ring condensed with another aromatic ring, such as naphthalene and the like, which may have a substitution group. Particularly preferred are compounds represented by the following structural formulas (A-1') to (A-5').Chem. Fig. 4(where m independently represents an integer from 0 to 6.)

[0043] In the above structural formula, R independently represents a substitution group as described above.As mentioned above, a structure in which 100% of the hydrogen atoms in the cyclic structure of the main backbone are substituted with fluorine atoms is more suitable as constituent unit A. In other words, the most suitable structures are compounds expressed by the following structural formulas (A-1) through (A-5).Chem. Fig. 5

[0044] Example of compounds capable of forming constituent unit A include constituent units derived from monomers having a benzene ring, such as hexafluorobenzene, perfluorobiphenyl, perfluoronaphthalene, 4,4- difluorobenzophenone, 1 ,1 '-(1 ,1 ,2,2,3,3,4,4,5,5,6,6-dodecafluoro-1 ,6- hexanediyl)bis4-fluorobenzene, and the like, or constituent units derived from monomers having a cyclopentenyl group such as octafluorocyclopentene, and the like. As expressed in formulas (A-1 ) to (A- 5), more preferable examples are those derived from hexafluorobenzene, perfluorobiphenyl, perfluoronaphthalene, and octafluorocyclopentene.Constituent Unit B

[0045] Constituent unit B of the fluorine-containing compound described above contains a benzene ring in a main backbone, and has a structure in which fluorine atoms account for 30% or less of the number of atoms in the constituent unit. The constituent unit B preferably does not have a fluorine atom, and if a fluorine atom is included, it is important that the number of fluorine atoms in constituent unit B be 30% or less than the number of atoms in constituent unit B. This ensures excellent solvent solubility in fluorine- containing compounds and reliable synthesis of fluorine-containing compounds.

[0046] The benzene ring in the constituent unit B can have four or more ring structures in the main backbone, but two or three in the main backbone is preferable, and having one to four ring structures including the side chains is preferable.

[0047] Examples of the constituent unit B include benzene, biphenyl, terphenyl, indene, naphthalene, indane, acenaphthylene, fluorene, spirofluorene, benzofluorene, dibenzofluorene, phenalene, phenanthrene, anthracene, fluoranthene, triphenylene, pyrene, chrysene, naphthacene, picene, perylene, pentaphene, hexacene, pentacene, rubicene, coronene, ovalene, isoindoline, indoline, indazoline, quinoline, isoquinoline, benzoquinoline, phthalazine, quinoxaline, quinazoline, cinnoline, galvazole, phenanthridine, acridine, phenanthroline, phenazine, benzimidazole,benzofuran, benzothiophene, isobenzothiazole, benzoxazole, isobenzoxazole, dibenzofuran, dibenzothiophene, benzocarbazole, dibenzocarbazole, and the like, which may have a substitution group.

[0048] Examples of these substitution groups include the substitution groups suggested in the aforementioned constituent unit A.

[0049] Such a constituent unit B preferably is a constituent unit derived from bisphenols as shown in the following formula (B).Chem. Fig. 6

[0050] In the formula, L represents a structure according to the following Formulas (b-1) or (b-2).Chem. Fig. 7

[0051] R1and R2in the aforementioned formulas (b-1) and (b-2) independently represent a group selected from a group consisting of hydrogen atoms, C1 to C10 alkyl groups, C1 to C10 haloalkyl groups, andC6 to C10 aryl groups, or R1and R2may be combined together to form a ring structure that may include substitution groups.

[0052] Examples of C1 to C10 alkyl groups include methyl groups, ethyl groups, propyl groups, 2-methylpropyl groups (isobutyl groups), butyl groups, pentyl groups, and the like. Examples of C1 to C10 haloalkyl groups include trifluoromethyl groups, pentafluoroethyl groups, perfluoropropyl groups, and the like. Examples of C6 to C10 aryl groups include phenyl groups and naphthyl groups (including 1 -isomers and 2-isomers).

[0053] Alternatively, R1and R2together may be a group forming a ring structure which may have a substitution group. Examples of groups forming the ring structure include tetramethylene groups (forming a cyclopentane ring), pentamethylene groups (forming a cyclohexane ring), undecamethylene groups (forming a cyclododecane ring), 2-methyl- pentamethylene groups (forming a methylcyclohexane ring), 2,2,4- trimethyl-pentamethylene group (forming a trimethylcyclohexane ring), biphenyl -2,2'-diyl groups (forming a fluorene ring), and the like.

[0054] In Formula (B) above, R3and R4may each independently represent a hydrogen atom, a fluorine atom, a C1 to C10 saturated or unsaturated hydrocarbon group in which some or all hydrogens may be substituted by a halogen or a C6 to C10 aryl group in which some or all hydrogens may be substituted by a halogen. Examples of C1 to C10 saturated or unsaturated hydrocarbon groups in which some or all hydrogens may be substituted with a halogen include methyl groups, ethyl groups, propyl groups, 2-methylpropyl groups (isobutyl groups), butyl groups, pentyl groups, trifluoromethyl groups, pentafluoroethyl groups, perfluoropropyl groups, vinyl groups, allyl groups, 1-methylvinyl groups, 2- butenyl groups, 3-butenyl groups, and the like. Examples of C6 to C10 aryl groups in which some or all hydrogens may be substituted with a halogen include phenyl groups, naphthyl groups (including 1 -isomers and 2- isomers), perfluorophenyl groups, and the like.

[0055] Preferred examples of the constituent unit B include bisphenol AF (2,2-bis(4-hydroxyphenyl) hexafluoropropane), bisphenol F (bis(4-hydroxyphenyl) methane), bisphenol Z (1 ,1 -bis(hydroxyphenyl) cyclohexane), bisphenol A (2,2'-bis(4-hydroxyphenyl) propane), bisphenol C (2,2-bis(3-methyl-4-hydroxyphenyl) propane), 4-hydroxyphenylbutane, and 4,4'-(1 ,3-dimethylbutylidene) diphenol, bisphenol P (1 ,4-bis(2-(4- hydroxyphenyl)-2-propyl) benzene), 2,2-bis(3,5-dimethyl-4-hydroxyphenyl) propane, and the like, and among these, constituent units derived from bisphenol AF and bisphenol Z are preferable.Constituent Unit C

[0056] Constituent unit C of the fluorine-containing compound described above has a structure derived from a reactive compound having an olefinic carbon-carbon double bond or carbon-carbon triple bond, thereby providing excellent thermosetting (crosslinking) properties that enable molding of cured products with a high gel fraction even without using a crosslinking agent. Furthermore, constituent unit C preferably contains at least one fluorine atom, and specifically, the number of fluorine atoms is preferably 50% or less of the number of atoms in the constituent unit. Thereby, in conjunction with the fluorine atom in the constituent unit A, excellent electrical properties and flame retardancy can be provided.

[0057] Furthermore, the constituent unit C preferably has a benzene ring.

[0058] A preferable constituent unit C includes one of structures (C-1 ) to (C-10) below.Chem. Fig. 8

[0059] In the formula, p is an integer from 0 to 4. In some aspects, p is 4. In another aspect, p is 0. R represents a group selected from a group consisting of C1 to C10 alkyl groups and C6 to C10 aryl groups. R' represents a hydrogen atom or a C1 to C10 alkyl group.

[0060] Constituent unit C particularly preferably has the following structures (C-11) to (C-15).Chem. Fig. 9Other

[0061] The fluorine-containing compound that constitutes the fluorine- containing composition of the present invention is not excluded from containing small amounts of other constituent units other than constituent units A to C to the extent that the aforementioned various functions provided by constituent units A to C are not impaired.

[0062] For example, for improvement of electrical properties, a constituent unit derived from an aliphatic diol compound that does not contain a benzene ring and a fluorine atom, or an alicyclic diol compound that does not contain a benzene ring and fluorine atom can be included in an amount of 20 mol% or less of all constituent units included in the fluorine- containing compound.

[0063] Examples of these aliphatic diol compounds containing neither a benzene ring nor a fluorine atom include: ethylene glycol, 1 ,2-propanediol, 1 ,3-propanediol, 1 ,2-butanediol, 1 ,3-butanediol, 1 ,4-butanediol, 2,3- butanediol, 1 ,5-pentanediol, 1 ,5-hexanediol, 2,5-hexanediol, 1 ,6- hexanediol, 1 ,7-heptanediol, 1 ,8-octanediol, 1 ,9-nonanediol, 1 ,10- decanediol, 1 ,12-dodecanediol, 2-methyl-1 ,3-propanediol, 2-butyl-2-ethyl- 1 ,3-propanediol, neopentyl glycol, 3-methyl-1 ,5-pentanediol, 2-n-butyl-2-ethyl-1 ,3-propanediol, 2 ,2-diethy 1-1 ,3-propanediol, 2 ,4-d iethyl-1 ,5- pentanediol, 1 ,2-hexaneglycol, 1 ,2-octylglycol, 2-ethyl-1 ,3-hexanediol, 2- ethyl-1 ,6-hexanediol, 2, 3-di isobutyl-1 ,3-propanediol, 2,2-diisoamyl-1 ,3- propanediol, 2-methyl-2-propyl-1 ,3-propanediol, 2-methyl-1 ,8-octanediol, and the like.

[0064] Examples of alicyclic diol compounds containing neither a benzene ring nor a fluorine atom include: cyclohexanediols such as 1 ,2- cyclohexanediol, 1 ,3-cyclohexanediol, 1 ,4-cyclohexanediol and 2-methyl- 1 ,4-cyclohexanediol and the like; cyclohexanedimethanols such as 1 ,2- cyclohexanedimethanol, 1 ,3-cyclohexanedimethanol and 1 ,4- cyclohexanedimethanol, and the like; norbornanedimethanols such as 2,3- norbornanedimethanol and 2,5-norbornanedimethanol; tricyclodecanedimethanol; pentacyclopentadecanedimethanol; 1 ,3- adamantanediol; 2,2-adamantanediol; decalindimethanol; 2, 2,4,4- tetramethyl-1 ,3-cyclobutanediol; isosorbide; 3,9-bis(2-hydroxyethyl)- 2,4,8,10-tetraoxaspiro(5.5) undecane; 3,9-bis(2-hydroxy-1 ,1- d i m ethy I ethy l)-2 , 4, 8, 10-tetraoxaspiro(5.5) undecane; 3,9-bis(2-hydroxy-1 .1 -diethylethyl)-2,4,8, 10 -tetraoxaspiro(5.5) undecane; 3,9-bis(2-hydroxy-1 .1-dipropylethyl)-2,4,8,10-tetraoxaspiro(5.5) undecane, and the like.Preferred Embodiments

[0065] Examples of fluorine-containing compounds suitable for use in the present invention include, but are not limited to, compounds having the following structure (in the formulas, "(*)" indicates the bonding position).

[0066] In the formulas (1) to (10) described below, the value of n is preferably larger than 1 and less than 30, more preferably 2 or more and 20 or less, and even more preferably 5 or more and 10 or less as has been described above.Chem. Fig. 10Chem. Fig. 11

[0067] In the present invention, the fluorine-containing compound is preferably soluble in a solvent. The fluorine-containing compound being "soluble in a solvent" means 1 g or more, preferably 10 g or more, of thefluorine-containing compound is dissolved per 100 g of a solution obtained from a given solvent. The fluorine-containing compound of the present embodiment is preferably soluble in hydrocarbons described later. Furthermore, from the perspective of cost, the fluorine-containing compound of the present embodiment is particularly preferably soluble in toluene.

[0068] The fluorine content of the fluorine-containing compound in the fluorine-containing composition of the present invention is preferably 20 to 40 mass% of the total mass of the fluorine-containing compound, although there is no limitation to this range as long as the fluorine atom content ratio specified in each of the aforementioned constituent units A to C is satisfied. Thereby excellent electrical properties as well as excellent solvent solubility and flame retardancy can be provided.Bifunctional Crosslinking Agent

[0069] The bifunctional crosslinking agent constituting the fluorine- containing composition of the present invention includes a compound having two olefinic carbon-carbon double bonds in a molecule. Examples of this type of crosslinking agent include: methacrylate compounds, acrylate compounds, allyl compounds, vinyl compounds, and the like. Methacrylate or acrylate compounds are preferable due to their high cross-linking reactivity, and acrylate compounds are particularly preferred.

[0070] Examples of these crosslinking agents include: cyclohexane dimethanol divinyl ether (CHDVE), diethylene glycol divinyl ether (DEGDVE), tri(ethylene glycol) divinyl ether (TEGDVE), butanediol divinyl ether (BDVE) and the like. These can also be commercially available products, such as Karenz (registered trademark) MOI-EG (2-(2- methacryloyloxyethyloxy)ethyl isocyanate) manufactured by RESONAC CORPORATION, Ebecryl (registered trademark) 8402 (bifunctional aliphatic urethane acrylate) manufactured by Daicel-Allnex Ltd. Ebecryl (registered trademark) 150 (EO modified bisphenol A diacrylate), and the like.

[0071] The bifunctional crosslinking agent used in the present invention should not contain fluorine atoms. The absence of fluorine atoms increases adhesion between the composition and conductors or other resin layers.

[0072] In addition, when the bifunctional crosslinking agent has a cyclic structure in the main frame thereof, the resulting cured product tends to be more flexible. Therefore, when higher flexibility is required, a bifunctional crosslinking agent having a cyclic structure in the main backbone thereof is preferable.Other additives

[0073] Furthermore, the fluorine-containing composition of the present invention may further contain any additives known in the art as optional components, such as reaction initiators, fillers, antifoaming agents, thermal stabilizers, antistatic agents, ultraviolet absorbers, colorants (dyes or pigments), flame retardants, lubricants, dispersants, and the like.Preparation of the Composition

[0074] The fluorine-containing composition of the present invention can be prepared by mixing the fluorine-containing compound, a crosslinking agent, and other optionally selected components described above. Heating may be carried out during mixing. In addition, mixing can also be carried out using an arbitrary mixing device known in the art, such as various stirrers, ball mills, bead mills, planetary mixers, roller mills, and the like.Varnish

[0075] Another embodiment of the invention is a varnish containing the fluorine-containing composition of the invention described above and a solvent.

[0076] Any type of solvent can be used as the solvent; however, from the perspective of solvent solubility, an aprotic solvent is preferably used in the present invention. The aprotic solvent may include: hydrocarbons such as benzene, toluene, xylene, heptane, cyclohexane, methylcyclohexane, mineral spirit, and the like; ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), diisobutyl ketone (DIBK), and thelike; cyclic ketones such as cyclohexanone, cycloheptanone, cyclooctanone, and the like; esters such as ethyl acetate, butyl acetate, y- butyrolactone, and the like; cyclic ethers such as tetrahydrofuran (THF), 1 ,3- dioxolane, and the like; amides such as N,N-dimethylformamide (DMF), diethylformamide (DEF), N,N-dimethylacetamide (DMAc), N- methylpyrrolidone (NMP), N-cyclohexyl pyrrolidone, and the like; sulfones such as sulfolane, dimethylsulfone, and the like; and sulfoxides such as dimethylsulfoxide (DMSO). Preferable solvents for the present invention are hydrocarbons, and particularly preferably aromatic hydrocarbons.

[0077] The concentration of the varnish should be such that the fluorine- containing compound and bifunctional crosslinking agent are uniformly dispersed. Although there is no particular restriction, the concentration of the varnish should be 40 to 70% by mass, preferably 45 to 65% by mass, and more preferably 50 to 60% by mass as the solid content concentration.

[0078] The use of a reaction initiator is suitable for achieving more efficient cross-linking and curing under more relaxed conditions. Examples of the reaction initiators that can be used include benzoyl peroxide, di-t-butyl peroxide, t-butyl hydroperoxide, dicumyl peroxide, cumyl hydroperoxide, a,a'-di (t-butylperoxy)-diisopropylbenzene (Perbutyl P (registered trademark) available from NOF Corporation), bis(1-methyl-1 -phenylethyl) peroxide (Percumyl D (registered trademark) available from NOF Corporation), 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne (Perbutyl C (registered trademark) available from NOF Corporation), 3, 3', 5,5'- tetramethyl-1 ,4-diphenaquinone, chloranyl, 2,4,6-tri-t-butylphenoxyl, t-butyl peroxyisopropyl monocarbonate, azobisisobutyronitrile, and the like.

[0079] In the present invention, the filler may be an organic filler or an inorganic filler. Examples of organic fillers that can be used include: engineering plastics such as polyphenylene sulfide, polyether ether ketone (PEEK), polyamide, polyimide, polyamide-imide, and the like; and solventinsoluble fluororesins such as polytetrafluoroethylene (PTFE), perfluoroalkoxy alkane (PFA), and copolymers (FEP) of tetrafluoroethylene, hexafluoropropylene, and the like. Examples of inorganic fillers that can be used include: metals; aluminum oxide, zinc oxide, tin oxide, titanium oxide,and other metal oxides; metal hydroxides; titanic acid metal salts; zinc borate; zinc stannate; boehmite; silica; glass; silicon oxide; silicon carbide; boron nitride; calcium fluoride; carbon black; mica; talc; barium sulfate; molybdenum disulfide; and the like. Solvent-insoluble fluororesin is preferable in terms of improving the electrical properties (dielectric constant, dielectric loss, and the like) of the cured product of the fluorine-containing composition. Furthermore, silica is preferable in that the coefficient of thermal expansion can be reduced without impairing the electrical properties (dielectric constant, dielectric loss, and the like) of the cured product of the fluorine-containing composition.Insulated Electrical Wire

[0080] Another embodiment of the present invention is an insulated electrical wire composed of a conductor and an insulating film that is an insulated electrical wire where the insulating film is composed of the fluorine-containing composition of the present invention described above.

[0081] For the insulated electrical wire, the insulating film is formed on the outer circumference of the conductor and the conductor and insulating film may be in contact or another resin layer may be interposed between the conductor and the insulating film.

[0082] The conductor used in the present invention can be one conventionally used for insulated electrical wire, and examples include copper, copper alloy, copper clad aluminum, aluminum, silver, gold, galvanized iron, and other metal conductors.

[0083] The cross-sectional shape perpendicular to the longitudinal direction of the conductor used in the present invention is not particularly limited, and examples include a conductor with a circular or rectangular (rectangular shape) cross-sectional shape. Rectangular conductors are particularly suitable because of their high occupancy ratio during winding. The insulating film of the present invention has excellent flexibility and so can be suitably used in applications where a large number of insulated wires are incorporated in a narrow space, in other words, in applications where much bending is performed.

[0084] The size of the conductor is not particularly limited, but in the case of a rectangular conductor with a rectangular cross-sectional shape, a width (long side) of 1.0 to 10.0 mm is preferable, 1.0 to 5.0 mm is more preferable, and 1.4 to 4.0 mm is even more preferable, and a thickness (short side) of 0.4 to 3.0 mm is preferable, and 0.5 to 2.5 mm is more preferable. The ratio of width (long side) to thickness (short side) (thickness:width) is preferably 1 :1 to 1 :20, and more preferably 1 : 1 to 1 :4. On the other hand, for conductors with a circular cross-sectional shape, a diameter of 0.3 to 3.0 mm is preferable, and 0.4 to 2.7 mm is more preferable.

[0085] The insulating film for the insulated electrical wire of the present invention is formed by applying the varnish of the present invention directly to a conductor or having another layer interposed therebetween and then baking the varnish. Conventional methods for applying varnish can be used, such as dipping a conductor or a conductor with another layer formed in advance into the varnish, or using a varnish application die.

[0086] The baking method is not restricted. For example, a baking furnace can be used to heat the product to 100 to 600°C for 10 seconds to 12 hours.

[0087] The thickness of the insulating film is, for example, 1 to 300 pm, preferably 10 to 150 pm.

[0088] The application and / or baking may be repeated until the desired insulating film is obtained.

[0089] The other layer described above is a layer different from the insulating film. Examples include layers made of aromatic polyetherketone resin, fluororesin, polyamide-imide, polyetherimide, polyethersulfone, and polyphenylene sulfide.EXAMPLES

[0090] The present invention will be described below in further detail based on examples and comparative examples. However, the present invention is not limited to these examples.

[0091] Crosslinking agents used in the examples and comparative examples are as follows.■ Cyclohexanedimethanol divinyl ether (CHDVE): manufactured by NIPPON CARBIDE INDUSTRY CO., INC., divinyl compound (bifunctional cross-linking agent)■ Tri(ethylene glycol)divinylether (TEGDVE): manufactured by NIPPON CARBIDE INDUSTRY CO., INC., divinyl compound (bifunctional cross-linking agent)■ 1 ,4-butanediol divinyl ether (BDVE): manufactured by NIPPON CARBIDE INDUSTRY CO., INC., divinyl compound (bifunctional crosslinking agent)■2-(2-methacryloyloxyethyloxy)ethyl isocyanate: Karenz (registered trademark) MOI-EG manufactured by Resonac Co., bifunctional crosslinking agent with methacrylate and isocyanate groups■ Bifunctional urethane acrylate: Ebecryl (registered trademark) 8402 manufactured by Daicel-Allnex Corporation, aliphatic urethane acrylate compound (bifunctional cross-linking agent)■ EO modified bisphenol A diacrylate: Ebecryl (registered trademark) 150 manufactured by Daicel-Allnex Corporation, diacrylate compound (bifunctional cross-linking agent)■Triallyl isocyanurate: TAIC (registered trademark) manufactured by Shinryo Corporation, triallyl compound (trifunctional cross-linking agent)■Trifunctional urethane acrylate: KRM 8667 manufactured by Daicel- Ornex Corporation, aliphatic urethane acrylate compound (trifunctional cross-linking agent)■ 1 ,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl)-1 , 3, 5-triazinane-2, 4,6- trione: Karenz MT (registered trademark) NR1 manufactured by Resonac Corporation, trithiol compound (trifunctional cross-linking agent)■ Pentaerythritol tetrakis(3-mercaptobutyrate): Karenz MT (registered trademark) PE1 manufactured by Resonac Corporation, tetrathiol compound (tetrafunctional cross-linking agent)Example 1

[0092] 0.400 g of a fluorine-containing compound expressed by the following formula was mixed with 0.600 g of methyl ethyl ketone (MEK) and stirred at 60°C for20 minutes to dissolve. Aftercooling to room temperature, 0.267 g of cyclohexanedimethanol divinyl ether (CHDVE), a bifunctional cross-linking agent, and 0.013 g of bis(1 -methyl-1 -phenylethyl) peroxide, a reaction initiator (Percumyl (registered trademark) D manufactured by NOF Corporation), were added and stirred at room temperature for 10 minutes to obtain a composition. The content ratio of the bifunctional crosslinking agent is 40% by mass, based on a total of the fluorine-containing compound and bifunctional crosslinking agent of 100% by mass.Chem. Fig. 12(n = 7)

[0093] The above composition was applied to a 100 mm x 100 mm x 0.1 mm thick aluminum metal plate using an applicator (wet film coater "Jieoto" (registered trademark) No. 5) with a gap size of 400 pm. The test pieces were placed in a thermostatic oven (STPH-202M manufactured by ESPEC Corporation) set to 210°C for 10 minutes for pre-drying, and then placed in a thermostatic oven set at 500°C for 2 minutes for baking. The coating thickness after baking was 70 pm.Examples 2 to 9, comparative examples 1 to 12

[0094] Similar to Example 1 , compositions were prepared with the crosslinking agents and crosslinking agent content ratios shown in Table 1 below to obtain test pieces.Comparative Example 13

[0095] Test pieces were obtained in the same manner as in Example 2, except that a fluorine-containing compound expressed by the following formula was used.Chem. Fig. 13(n = 1)Comparative Example 14

[0096] Test pieces were obtained in the same manner as in Example 2, except that a fluorine-containing compound expressed by the following formula was used.Chem. Fig. 14(n = 36)Reference Example

[0097] A commercially available polyimide resin precursor varnish was applied to an aluminum metal plate in place of the fluorine-containing compound in Example 1. A metal plate coated with polyimide resin (test piece) was obtained by placing the test piece in a thermostatic chamber set to 150°C for 10 minutes for pre-drying and then in a thermostatic chamber set to 500°C for 2 minutes for baking and inducing the imidization reaction.Flexibility evaluation

[0098] The test pieces obtained in the Examples, Comparative Examples, and Reference Examples were placed on a 4 mm diameter steel rod with the coated surface facing outward and bent 180 degrees (U-shape) (see FIG. 1). Cracking in the coating on the edges of the bent section was evaluated, and rated as "O" if no cracks were observed, and "X" if cracks were observed. The test pieces rated as "O" were further bent with the steel bars removed until the metal sheets were in close contact with each other, and the test pieces were rated "©" if no cracks were observed on the edges of the bent section (see FIG. 2). The results are shown in Table 1 .Table 1Table 1 (continued)

[0099] The results in Table 1 indicate that Examples 1 -9 using a bifunctional crosslinking agent exhibited superior flexibility, while Comparative Examples 6-11 using a trifunctional crosslinking agent and Comparative Example 12 using a tetrafunctional crosslinking agent exhibited no flexibility. Also, in contrast to Examples 1 and 2, no flexibility was observed in Comparative Examples 2 and 3, which used the same bifunctional crosslinking agent but with a smaller ratio of crosslinking agent added, or in Comparative Example 4, which had a larger ratio of crosslinking agent added. Furthermore, no flexibility was observed in Comparative Examples 13 and 14, where only the degree of polymerization of the fluorine-containing compound differs from that of Example 2.Dielectric Constant Evaluation

[0100] Compositions from Examples 2, and 7 to 9 and the reference example were dropped into a boat-shaped aluminum foil pan 3 mm wide, 40 mm long and 7 mm high. A hot plate was used to heat to 150°C for 40 minutes to remove the MEK. The hot plate was used to further heat at a heating rate of 10°C / min up to 250°C. The temperature was then maintainedat 250°C for 80 minutes to obtain a cured product. After cooling to room temperature, the cured product was peeled off from the aluminum pan. The cured product was sanded with sandpaper to a length of 30 mm ± 0.1 mm to obtain a rod shaped sample.

[0101] The dielectric constant of the obtained test pieces was measured in accordance with ASTMD2520 using a 1 GHz cavity resonator (DPS18 manufactured by KEYCOM Corp.). The dielectric constant was measured in an environment with a temperature of 23°C ± 1 °C and a humidity of 50%RH ± 5%RH. The obtained results are shown in Table 2.Table 2

[0102] From the results in Table 2, it is clear that the compositions in the examples all exhibit dielectric constants that are even better than those of the conventionally used polyimide resin (reference example).INDUSTRIAL APPLICABILITY

[0103] The present invention can provide a cured product with both superior flexibility and low dielectric constant. The cured product is useful as an insulating film for an insulated electrical wire and can be widely used in fields where both flexibility and insulation properties are required, such as flexible board materials.DESCRIPTION OF CODES1 . Test sample2. Steel rod

Claims

Claims1. A fluorine-containing composition comprising: a fluorine-containing compound; and a bifunctional crosslinking agent, wherein the fluorine-containing compound contains: constituent unit A containing a 3- to 12-membered cyclic structure in a main backbone and having a structure in which 50% or more of the hydrogen atoms in the cyclic structure have been substituted with fluorine atoms; constituent unit B containing a benzene ring in a main backbone, and having a structure in which the number of fluorine atoms is 30% or less of the number of atoms in the constituent unit; and constituent unit C containing an olefinic carbon-carbon double bond or a carbon-carbon triple bond, wherein the aforementioned constituent units A through C are bonded in the order C-B-(A-B)n-C or C-A-(B-A)n-C(wherein n is greater than 1 and less than 30); and the ratio of the bifunctional crosslinking agent is greater than 30 mass% to less than 70 mass%, based on the total of the fluorine-containing compound and the bifunctional crosslinking agent being 100 mass%.

2. The fluorine-containing composition according to claim 1 , wherein the fluorine-containing compound has the structure of formula (I);Chem. Fig. 1In the formula, L represents a structure of the following Formula (II) or (III).Chem. Fig. 2R1and R2each independently represent a group selected from a group consisting of a hydrogen atom, C1 to C10 alkyl groups, C1 to C10 haloalkyl groups, and C6 to C10 aryl groups, or R1and R2may be combined together to form a ring structure that may include substitution groups;R3and R4each independently represent a group selected from a group consisting of a hydrogen atom, a fluorine atom, C1 to C10 saturated or unsaturated hydrocarbon groups in which some or all hydrogens may be substituted by a halogen, and C6 to C10 aryl groups in which some or all hydrogens may be substituted by a halogen atom; n is in a range of greater than 1 and less than 30; andX represents a group containing an olefinic carbon-carbon double bond or a carbon-carbon triple bond.

3. The fluorine-containing composition according to claim 2, wherein X includes at least one fluorine atom; andL represents a group selected from the group consisting of cyclopentylidene groups that may have a substitution group, cyclohexylidene groups that may have a substitution group, and cyclododecylidene groups that may have a substitution group.

4. The fluorine-containing composition according to claim 3, having the following structure;Chem. Fig. 3in the formula, n is greater than 1 and less than 30.

5. The fluorine-containing composition according to any one of claims 1 to 4, wherein the bifunctional crosslinking agent does not contain fluorine atoms.

6. A varnish, comprising: a solvent and the fluorine-containing composition according to any one of claims 1 to 4.

7. The varnish according to claim 6, wherein the bifunctional crosslinking agent does not contain fluorine atoms.

8. An insulated electrical wire, comprising: a conductor; and an insulating film, wherein the insulating film is composed of the fluorine-containing composition according to any one of claims 1 to 4.

9. The insulated wire according to claim 8, wherein the bifunctional crosslinking agent does not contain fluorine atoms.

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