WO2024226888A1 - Fluorine-containing compounds for use in high-frequency substrates - Google Patents

Abstract

To provide a fluorine-containing compound that has excellent electrical properties, excellent thermosetting properties, a high glass transition temperature of the cured product, and excellent flame retardancy, enabling fabrication of substrates with excellent electrical properties required for the next-generation high frequencies. 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 bond or a carbon-carbon triple bond; wherein constituent units A to C are made by bonding the constituent unit C at an end.

Description

TITLE OF THE INVENTION FLUORINE-CONTAINING COMPOUND CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of priority of Japanese Patent Application No. 2023-073743 filed April 27, 2023, and Japanese Patent Application No. 2023-221747 filed December 27, 2023, the disclosures of which are incorporated herein by reference in their entirety. FIELD OF THE INVENTION [0002] The present invention relates to a fluorine-containing compound, and more particularly, to a fluorine-containing compound having excellent electrical properties suitable for use in next-generation high-frequency substrates, and having excellent flame retardancy, curability, and solvent solubility. BACKGROUND OF THE INVENTION [0003] In recent years, information and communication apparatuses such as smartphones, tablet terminals, and the like have been developed for next- generation high frequencies that enable high-speed and large-capacity transmission, and in response, substrate materials used are required to have a low dielectric constant and low dielectric tangent to reduce transmission loss. [0004] Conventionally, materials such as epoxy resins, polyphenylene ether resins, and the like have been used as resin materials for high-speed communication and transmission (Patent Document 1). However, it is difficult for epoxy resins and polyphenylene ether resins to handle high-speed and large-capacity transmissions of recent years. Furthermore, the substrate material is also required to have flame retardancy, but the polyphenylene ether resin has inferior flame retardancy, so it is necessary to add a flame retardant. [0005] A halogen-based flame retardant has been conventionally used as a flame retardant to be added to a thermosetting resin, but from the perspective of safety and influence on the environment during disposal and incineration, there is demand for a flame retardant that does not contain a halogen. [0006] In recent years, there have been attempts to add phosphorus- based or inorganic flame retardants, but the addition of a flame retardant may cause a decrease in heat resistance and deterioration in electrical properties. For example, a phosphorus-based flame retardant does not contribute to curing but acts as a plasticizer, so heat resistance is deteriorated due to insufficient curing. Furthermore, it is known that an inorganic flame retardant increases the water absorption of the resin composition and causes deterioration of electrical properties. [0007] In contrast, fluororesins are known as materials having excellent electrical properties. In particular, perfluororesins in which all of the hydrogens in a molecular chain are substituted with fluorine are known to exhibit particularly excellent electrical properties (dielectric constant, dielectric loss, and the like). However, fluororesins (perfluororesins) have issues such as ease of deformation (due to stress), a high coefficient of thermal expansion, and the like, making them difficult to use as substrate materials. [0008] The use of fluorinated poly(arylene ether) and crosslinkable fluorinated poly(arylene ether) has been proposed as a dielectric material for electronic components (Patent Documents 2 and 3). However, the electrical properties of the materials do not satisfy the current high-speed communication and transmission requirements. In order to obtain a cured product with a high gel fraction, the product must be heated at a high temperature of 400°C or higher; therefore, from the perspective of mass production and reduction of manufacturing costs, there is a need to lower the crosslinking treatment temperature. [0009] As a solution to these problems, the present inventors and the like proposed the fluororesin described in Patent Document 4 below. PRIOR ART DOCUMENTS [0010] [Patent Document 1] Japanese Unexamined Patent Application 2017- 128718; [Patent Document 2] US Patent No.5115082 Specification; [Patent Document 3] US Patent No.5179188 Specification; and [Patent Document 4] Japanese Unexamined Patent Application 2022-89150 SUMMARY OF THE INVENTION [0011] The fluororesin described in Patent Document 4 is a resin material having excellent electrical properties (low dielectric constant and low dielectric loss), excellent dimensional stability, high solvent solubility for ease of thin film molding, excellent crosslinking properties which allow a film to be formed by heating at approximately 200°C, and excellent heat resistance, as a substrate material for high-speed communication and transmission. [0012] However, in order to create substrates that can support next- generation high frequencies above 5 GHz, the substrate material must have even more excellent electrical properties, a low coefficient of thermal expansion after thermosetting to enable use over a wide temperature range, a high glass transition temperature to enable use in high-temperature environments and soldering, the ability to mold a pre-preg used to fabricate the substrate securely, and the like. [0013] Therefore, an object of the present invention is to provide a fluorine- containing compound that has excellent electrical properties, as well as excellent thermosetting properties, a high glass transition temperature of the cured product, and excellent flame retardancy, enabling fabrication of substrates with excellent electrical properties required for the next-generation high frequencies. DETAILED DESCRIPTION OF THE INVENTION [0014] 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 bond or a carbon-carbon triple bond; wherein constituent units A to C are made by bonding the constituent unit C at an end. [0015] In the fluorine-containing composition of the present invention, it is preferable that: [1] the cyclic structure contained in constituent unit A is a benzene ring or cyclopentenyl group; [2] constituent units A to C bond in the order C-B-(A-B)_n-C ... (i) or C-A-(B-A)_n-C ... (ii) (where n = 1 to 4); [3] n is 1; [4] constituent unit A has 1 to 3 ring structures including side chains; [5] constituent unit A is any one of the following formulas (A-1) to (A-5). [6] constituent unit B has 1 to 4 ring structures including side chains; [7] constituent unit B is a bisphenol; [8] constituent unit C contains fluorine; [9] constituent unit C contains a benzene ring; [10] constituent unit C is perfluorostyrene; [11] the cured product has a gel fraction of 50% or more; and [12] the cured product has a glass transition temperature of 200°C or higher.

EFFECT OF THE INVENTION [0016] The presence of the above constituent units A to C in the fluorine- containing compound of the present invention provides not only excellent electrical properties, but also excellent flame retardancy, solvent solubility, and thermosetting (crosslinking) properties. [0017] This effect of the fluorine-containing compound of the present invention is evident from the results of the examples described later. In other words, the fluorine-containing compounds of the present invention shown in Examples 1 to 11 have excellent electrical properties even at high frequencies such as 28 GHz, and the gel fraction of the cured product cured under curing conditions of 200°C for 120 minutes is 50% or higher. Moreover, the cured product also has flame retardancy. [0018] In contrast, polyphenylene ether, which is conventionally used as a general-purpose substrate material, not only cannot handle high frequencies such as 28 GHz but is also inferior in flame retardancy (Comparative Example 4). In addition, a fluorine-containing compound having the same composition as in Example 1, except for the use of a constituent unit A with a fluorine atom content of less than 50%, is not sufficiently satisfactory in terms of flame retardancy, and if the constituent unit B has a fluorine atom content of 30% or more, results such as deterioration in solvent solubility are obtained (Comparative Example 1, Comparative Example 3). MODE FOR CARRYING OUT THE INVENTION (Fluorine-containing compound) [0019] 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 bond or 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. In other words, the compound has excellent electrical properties (low dielectric constant and low dielectric loss) and flame retardancy provided by the constituent unit A, excellent solvent solubility and high glass transition temperature provided by the constituent unit B, and excellent reactivity provided by the constituent unit C, which is located at the end of the compound, enabling the compound to have excellent thermosetting properties that enable molding of a cured product with high gel fraction even without using crosslinking agents. [0020] In the fluorine-containing composition of the present invention, it is preferable that constituent units A to C are bonded in the order of C-B-(A-B)_n- C (i) or C-A-(B-A)_n-C (ii), and the value of n is in the range from 1 to 4, with a low molecular weight compound in which the value of n is 1 being particularly preferable. Thereby the proportion of crosslinked points in the compound is increased, and a cured product with a high gel fraction (crosslink density) can be obtained without the use of a crosslinking agent. [0021] In the fluorine-containing compound of the present invention, 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] [0022] The constituent unit A that is included in the fluorine-containing compound of the present invention 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 the hydrogen atoms in the cyclic structure of the constituent unit A substituted with fluorine atoms. [0023] 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. [0024] 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, cyclooctatriene, 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. [0025] 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. [0026] Examples of substitution groups include the following substitution groups. [0027] 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; 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 substituent 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, 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; 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 substituent 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. [0028] A plurality of substitution groups may be present, in which case the substitution groups may be the same or different. [0029] 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').

(where m independently represents an integer from 0 to 6) [0030] In the above structural formula, R independently represents a substitution group as described above. [0031] 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 aforementioned structural formulas (A-1) through (A-5). [0032] 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] [0033] Constituent unit B of the fluorine-containing compound of the present invention 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. [0034] 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. [0035] 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. [0036] Examples of these substitution groups include the substitution groups suggested in the aforementioned constituent unit A. [0037] Such a constituent unit B preferably is a constituent unit derived from bisphenols as shown in the following formula (B).

[0038] In the formula, L represents a structure according to the following Formulas (b-1) or (b-2).

R¹ and R² in the aforementioned formulas (b-1) and (b-2) each 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 R¹ and R² may be combined together to form a ring structure that may include substitution groups. [0039] 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). [0040] Alternatively, R and R together 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. [0041] In Formula (B) above, R³ and R⁴ may 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, trifluoromethyll 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. [0042] Preferred examples of 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, 1,1-bis(4-hydroxy-3- methylphenyl)cyclohexane, 1,7-dihydroxynaphthalene, and the like, and among these, constituent units derived from bisphenol AF, bisphenol Z, and 1,1-bis(4- hydroxy-3-methylphenyl)cyclohexane are particularly suitable. [Constituent Unit C] [0043] The constituent unit C of the fluorine-containing compound of the present invention has a structure derived from a reactive compound having an olefinic carbon-carbon double bond or carbon-carbon triple bond, thereby provide 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. [0044] Furthermore, the constituent unit C preferably has a benzene ring. [0045] A preferable constituent unit C includes one of structures (C-1) to (C-10) below.

[0046] 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. [0047] Constituent unit C particularly preferably has the following structures (C-11) to (C-16). Chem.6 [Other] [0048] The fluorine-containing compound 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. [0049] 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. [0050] Examples of these aliphatic diol compounds containing neither a benzene ring nor a fluorine atom include: ethylene glycol, 1,2-propanediol, 1,3- propanediol, 1,2butanediol, 1,3butanediol, 1,4butanediol, 2,3butanediol, 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-diethyl-1,3-propanediol, 2,4- diethyl-1,5-pentanediol, 1,2-hexaneglycol, 1,2-octylglycol, 2-ethyl-1,3- hexanediol, 2-ethyl-1,6-hexanediol, 2,3-diisobutyl-1,3-propanediol, 2,2-diisoamyl- 1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-1,8-octanediol, and the like. [0051] 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- dimethylethyl)-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] [0052] Preferable fluorine-containing compounds of the present invention include, but are not limited to, compounds having the following structures. (where n is a value from 1 to 4, and "(*)" indicates the bonding position.) Chem.7

Chem.8

Chem.9 [0053] In the present invention, the fluorine-containing compound is preferably soluble in a solvent. The fluorine-containing compound is "soluble in a solvent" means 1 g or more, preferably 10 g or more, of the fluorine- 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. [0054] The fluorine content of the fluorine-containing compound 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. [0055] The fluorine-containing compound of the present invention preferably has a number average molecular weight in a range of 500 to 4000, particularly 1000 to 2000. Having a number average molecular weight in the above range improves the solvent solubility and crosslinking properties, and increases the gel fraction of the cured product as described later. (Synthesis of fluorine-containing compound) [0056] The fluorine-containing compound of the present invention can be manufactured by simultaneously blending compound A, having a 3- to 12- membered cyclic structure in the main backbone and where 50% or more of the hydrogen atoms in the cyclic structure are substituted with fluorine atoms, compound B, having a benzene ring in the main backbone where 30% or less of the atoms in the constituent unit are fluorine atoms, and reactive compound C, having an olefinic carbon-carbon double bond or carbon- carbon triple bond, followed by heating and mixing; or by first blending the aforementioned compound A and compound B, then blending the reactive compound C at a time when the condensation reaction of these compounds has not yet occurred, and then heating and mixing. [0057] Specifically, when synthesizing a fluorine-containing compound with the structure shown in formula (i) above, compound A: compound B is blended in an equivalent ratio of 1:1.2 to 1:3.0, particularly 1:1.3 to 1:2.0, and reactive compound C is blended with compound A in a ratio of 1:0.2 to 1:2.5, particularly 1:0.3 to 1:2.0. [0058] Furthermore, when synthesizing a fluorine-containing compound with the structure shown in formula (ii) above, compound B: compound A is blended in an equivalent ratio of 1:1.2 to 1:3.0, particularly 1:1.3 to 1:2.0, and reactive compound C is blended with compound B in a ratio of 1:0.2 to 1:2.5, particularly 1:0.3 to 1:2.0. [0059] For the reaction of compounds A to C, it is preferable to include a basic substance as a de-HF agent. [0060] Examples of such basic substances include carbonates, bicarbonates, and hydroxides of alkali metals. Specific examples that are preferably used include sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, and potassium hydroxide. [0061] The basic substance is preferably a basic substance having a normality of 2 Normal or higher, and preferably 4 to 6 Normal as a base per 1 mol of compound B. [0062] Compounds A to C can be mixed by adding all of the aforementioned basic substances to the reaction solvent at the same time. However, if Compounds A and B are solids (perfluorobiphenyls, bisphenols, and the like) and Compound C is a liquid (perfluorostyrene and the like), Compound A, Compound B and the basic substances are added to a reaction container after drawing a vacuum and then filling with nitrogen, after which, the reaction solvent is added, and then Compound C is preferably added. In other words, perfluorostyrene, which is preferably used as compound C, is highly volatile. Therefore, such a compound is preferably used by adding after vacuum degassing and nitrogen replacement in the reactor. [0063] The process is preferably performed in an aprotic polar solvent or in a mixed solvent containing an aprotic polar solvent as the reaction solvent. Examples of preferred aprotic polar solvents include N, N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), sulfolane, and the like. The mixed solvent may contain a low polarity solvent, provided that the solubility of the fluorine-containing compound is not reduced and the reaction is not affected. [0064] Examples of low polarity solvents that can be used include toluene, xylene, benzene, tetrahydrofuran, benzotrifluoride((trifluoromethyl)benzene), xylene hexafluoride(1,3-bis(trifluoromethyl)benzene), and the like. The polarity (dielectric constant) of the solvent mixture can be changed by the addition of a low polarity solvent to control the rate of the condensation reaction. [0065] Heating and mixing of compounds A to C cannot be generally specified because they vary depending on the type of compound used, but the reaction must be controlled so that the value of n in the above formulas (i) or (ii) is within the range of 1 to 4. The reaction temperature is preferably 10 to 200 C and the reaction time preferably 1 to 80 hours, more preferably a reaction temperature of 20 to 180°C and a reaction time of 2 to 60 hours, and even more preferably a reaction temperature of 50 to 160°C and a reaction time of 3 to 40 hours, appropriately selected depending on the type of compound to be used. [0066] After the reaction is completed, the resulting reaction mixture is cooled, separated, washed, and dried to obtain the fluorine-containing compound. [0067] Synthesis of the fluorine-containing compound of the present invention is preferably performed by the aforementioned method, from the perspectives of effectively controlling the value of n (in other words, degree of polymerization) in the above formulas (i) or (ii) and reducing the number of reaction steps. However, this does not preclude the use of the known method described in the aforementioned patent document 4 (Japanese Unexamined Patent Application 2022-89150), for example. (Fluorine-containing compositions) [0068] The fluorine-containing compound of the present invention has excellent crosslinking properties itself, and therefore can exhibit excellent curability even without a crosslinking agent. However, by using a crosslinking agent with the fluorine-containing compound, it is possible to provide even superior curability and to impart sufficient hardness to a cured product containing the fluorine-containing composition made using the fluorine- containing compound and a crosslinking agent. [0069] The crosslinking agent used in the fluorine-containing composition includes a compound having two or more olefinic carbon-carbon double bonds in a molecule. Examples of this type of crosslinking agent include a polyfunctional methacrylate compound having two or more methacryl groups in a molecule, a polyfunctional acrylate compound having two or more acrylic groups in a molecule, triallyl isocyanurate (TAIC) and other trialkenyl isocyanurate compounds, divinylbenzene, and the like. Examples of polyfunctional acrylate/methacrylate compounds include: dicyclopentadiene type acrylate compounds such as tricyclodecane dimethanol diacrylate and the like; and dicyclopentadiene type methacrylate compounds such as tricyclodecane dimethanol dimethacrylate and the like. [0070] Fluorine-containing composition may contain a crosslinking agent. Furthermore, in the fluorine-containing composition, the mass ratio of the fluorine-containing compound to the crosslinking agent is preferably within a range of 9.5:0.5 to 5:5, more preferably within a range of 7.5:2.5 to 5.5:4.5. The use of the mass ratio within this range can impart sufficient hardness to the cured product of the fluorine-containing composition. [0071] The fluorine-containing composition of the present embodiment may further contain a solvent, a reaction initiator, and/or a filler. Furthermore, the fluorine-containing composition of the present embodiment may further contain any additives known in the art, such as antifoaming agents, thermal stabilizers, antistatic agents, ultraviolet absorbers, colorants (dyes or pigments), flame retardants, lubricants, dispersants, and the like. [0072] The fluorine-containing composition may be a varnish-like composition containing a solvent, and various solvents can be used. 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 the like; cyclic ketones such as cyclohexanone, cycloheptanone, cyclooctanone, and the like; esters such as ethyl acetate, butyl acetate, γ-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. [0073] As described above, the fluorine containing compound of the present invention has excellent curing properties by itself, so crosslinking and curing by heating is possible even without the presence of a reaction initiator. However, if a reaction initiator is present, more efficient crosslinking and curing can be achieved under more relaxed conditions, so a reaction initiator is preferably used. Examples of the reaction initiators that can be used include benzoyl peroxide, di-t-butyl peroxide, t-butyl hydroperoxide, dicumyl peroxide, cumyl hydroperoxide, α,α'-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. [0074] The fluorine-containing composition of the present embodiment may further include one or a plurality of fillers. 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 solvent-insoluble fluororesins such as polytetrafluoroethylene (PTFE), perfluoroalkoxy alkane (PFA), and copolymer (FEP) of tetrafluoroethylene, hexafluoropropylene, and the like. Inorganic fillers that can be used include: a metal; 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. [0075] The fluorine-containing composition can be formed by mixing the fluorine-containing compound of the present invention, a crosslinking agent, and an optionally selected component. Heating may be carried out during mixing. 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, roll mills, and the like. (Cured product of fluorine-containing compound) [0076] As described above, the fluorine-containing compound of the present invention has excellent curability by itself, and even without a crosslinking agent, the cured product cured at 200°C for 120 minutes has a gel fraction (crosslink density) of 50% or higher, which provides far superior thermosetting properties. [0077] A gel fraction (crosslink density) of 80% or more is more preferred, 90% or more is even more preferred, and 100% is most preferred. A large gel fraction (crosslink density) may have the effect of suppressing a reduction in durability due to the presence of unreacted crosslinking sites and reducing the coefficient of thermal expansion due to an increase in crosslink density. A method of measuring gel fraction is described later. [0078] Furthermore, the glass transition temperature of the cured product is high, at 200°C or higher; therefore, the coefficient of thermal expansion is reduced in a normal use environment, and durability is improved when used as an electronic substrate. In addition, the low coefficient of thermal expansion at high temperatures offers advantages such as use in high- temperature environments, easier soldering, and the like. [0079] Furthermore, the coefficient of thermal expansion in a temperature environment above the glass transition temperature is preferably less than 200 ppm/°C, more preferably less than 180 ppm/°C, and even more preferably less than 150 ppm/°C. Methods for measuring the glass transition temperature and coefficient of thermal expansion are described later. [0080] The cured product of the fluorine containing compound of the present invention has excellent electrical properties, thermosetting properties, and flame retardancy, and thus is suitable for use in pre-pregs, copper clad laminated sheet, and printed circuits. [Pre-preg] [0081] The fluorine-containing compound of the present invention, or the aforementioned fluorine-containing composition containing the fluorine- containing compound blended with a crosslinking agent or the like can be preferably used in prepregs containing a semi-cured product of the fluorine- containing compound or composition and a fibrous base material. [0082] Examples of fibrous base materials that can be used in the pre- preg include glass woven fabrics, aramid woven fabrics, polyester woven fabrics, carbon fiber woven fabrics, glass nonwoven fabrics, aramid nonwoven fabrics, polyester nonwoven fabrics, carbon fiber nonwoven fabrics, pulp paper, linter paper, and the like. A preferable fibrous base material is a glass woven fabric capable of achieving excellent mechanical strength. The fibrous base material desirably has a thickness of 0.01 mm to 0.3 mm. [0083] In particular, the fluorine-containing compound of the present invention has excellent flame retardancy, so the amount of flame retardant conventionally added to the prepreg can be reduced or eliminated. As a result, the effect of flame retardants on electrical properties can be reduced or eliminated. [0084] The prepreg can be formed by impregnating the fluorine-containing compound or the fluorine-containing composition into the fibrous base material and then drying. Herein, the fluorine-containing compound or composition to be impregnated is preferably in a varnish state containing a solvent. The solvent can be any of the aforementioned solvents that can be used for the fluorine-containing composition. As a result of the drying process, the solvent in the varnish is at least partially removed and the fluorine-containing compound or composition becomes semi cured (the so called Bstage ). The impregnating step can be performed by an arbitrary method known in the art, such as dipping, application, or the like. By impregnating the fluorine- containing compound or composition a plurality of times, the amount of fluorine-containing compound in the prepreg can be adjusted. The conditions (temperature and time) of the drying step depends on the type of fluorine- containing compound and the type of optionally selected crosslinking agent, reaction initiator, and/or solvent. For example, the drying step can be performed by heating to a temperature of 80°C to 170°C for 1 to 60 minutes. [Copper clad laminated sheet] [0085] The cured product of the prepreg made of the fluorine-containing compound of the present invention can be preferably used in a copper clad laminated sheet. [0086] The copper clad laminated sheet can be formed by laminating one or a plurality of pre-pregs, laminating a copper foil on one or both surfaces thereof, and heating and pressurizing the obtained laminated product to integrate them. The fluorine-containing compound or composition in the copper clad laminated sheet is preferably in a state in which curing is complete (so-called "C stage"). The conditions of the heating and pressurizing process can be appropriately set based on the thickness of the copper clad laminated sheet to be manufactured, the composition of the fluorine-containing compound or composition in the prepreg, and the like. For example, the copper clad laminated sheet can be manufactured by heating to a temperature of 170°C to 220°C for 60 to 150 minutes and applying a pressure of 1.0 MPa to 10 MPa. [Printed circuit board] [0087] The cured product of the prepreg made of the cured product of the fluorine-containing compound of the present invention can be preferably used in a printed circuit board. [0088] The printed circuit board can be manufactured by etching the copper layer of the aforementioned copper clad laminated sheet to form a conductor pattern. Alternatively, the printed circuit board can be manufactured via a method in which one or a plurality of pre-pregs are laminated, heated, and pressurized to form a laminated body, with the conductive material laminated in a pattern on the surface of the laminated body to form a conductor pattern. EXAMPLES Chem.10 (Example 1) (Synthesis of fluorine-containing compound (n=1) of the above formula (1)) [0089] A glass reaction container was filled with 0.805 g (3.0 mmol) of 1,1- bis(4-hydroxyphenyl)cyclohexane (bisphenol Z), 0.501 g (1.5 mmol) of decafluorobiphenyl and 0.912 g (6.6 mmol) of potassium carbonate. The glass reaction container was decompressed to a vacuum and then substituted with nitrogen. Next, 10 mL of DMAc and 0.582 g (3.0 mmol) of 2,3,4,5,6- pentafluorostyrene were added to the glass reaction container. The reaction mixture was shielded from light, heated to 80°C with stirring, and then stirred for 15 hours. Upon completion of heating, the reaction mixture was cooled to room temperature. The reaction mixture was subsequently poured into 0.5 L of pure water. The reaction mixture was suction filtered and the obtained solid was washed with pure water and methanol. After washing, the solid fraction was dried under reduced pressure to obtain 1.54 g of a fluorine-containing compound. [0090] The resulting fluorine containing compound has a structural formula of the above formula (1), where the ratio of hydrogen atoms in the cyclic structure of constituent unit A substituted with fluorine atoms is 100% and the ratio of fluorine atoms in constituent unit B is 0%. [0091] The average degree of polymerization calculated from a nuclear magnetic resonance spectrum (X-Plus, a nuclear magnetic resonance device manufactured by Oxford Instruments) was 1.0. (Example 2) (Synthesis of fluorine-containing compound (n=2) of the above formula (1)) [0092] The procedure of Example 1 was repeated, except that 0.668 g (2.0 mmol) of decafluorobiphenyl and 0.388 g (2.0 mmol) of 2,3,4,5,6- pentafluorostyrene were used with respect to 0.805 g (3.0 mmol) of bisphenol Z to obtain 1.50 g of a fluorine-containing compound. [0093] The resulting fluorine-containing compound has a structural formula of the above formula (1), where the ratio of hydrogen atoms in the cyclic structure of constituent unit A substituted with fluorine atoms is 100% and the ratio of fluorine atoms in constituent unit B is 0%. [0094] The average degree of polymerization as determined by nuclear magnetic resonance spectroscopy was 1.9. (Example 3) (Synthesis of fluorine-containing compound (n=3) of the above formula (1)) [0095] The procedure of Example 1 was repeated, except that 0.752 g (2.3 mmol) of decafluorobiphenyl and 0.291 g (1.5 mmol) of 2,3,4,5,6- pentafluorostyrene were used with respect to 0.805 g (3.0 mmol) of bisphenol Z to obtain 1.61 g of a fluorine-containing compound. [0096] The resulting fluorine-containing compound has a structural formula of the above formula (1), where the ratio of hydrogen atoms in the cyclic structure of constituent unit A substituted with fluorine atoms is 100% and the ratio of fluorine atoms in constituent unit B is 0%. [0097] The average degree of polymerization as determined by nuclear magnetic resonance spectroscopy was 2.8. (Example 4) (Synthesis of fluorine-containing compound (n=4) of the above formula (1)) [0098] The procedure of Example 1 was repeated, except that 0.802 g (2.4 mmol) of decafluorobiphenyl and 0.233 g (1.2 mmol) of 2,3,4,5,6- pentafluorostyrene were used with respect to 0.805 g (3.0 mmol) of bisphenol Z to obtain 1.58 g of a fluorine-containing compound. [0099] The resulting fluorine-containing compound has a structural formula of the above formula (1), where the ratio of hydrogen atoms in the cyclic structure of constituent unit A substituted with fluorine atoms is 100% and the ratio of fluorine atoms in constituent unit B is 0%. [0100] The average degree of polymerization as determined by nuclear magnetic resonance spectroscopy was 3.5. Chem.11 (Example 5) (Synthesis of fluorine-containing compound (n=1) of formula (2) above) [0101] The procedures of Example 1 were repeated, except that 1.009 g (3.0 mmol) of 2,2-bis(4-hydroxyphenyl)hexafluoropropane (bisphenol AF) was used instead of 0.805 g (3.0 mmol) of bisphenol Z, and 0.408 g (1.5 mmol) of octafluoronaphthalene was used instead of 0.501 g (1.5 mmol) of decafluorobiphenyl, to obtain 1.61 g of the fluorine-containing compound. [0102] The resulting fluorine containing compound has the structural formula of the above formula (2), where the ratio of hydrogen atoms in the cyclic structure of constituent unit A substituted with fluorine atoms is 100% and the ratio of fluorine atoms in constituent unit B is 19%. [0103] The average degree of polymerization as determined by nuclear magnetic resonance spectroscopy was 1.0. Chem.12 (Example 6) (Synthesis of fluorine-containing compound (n=1) of formula (3) above) [0104] The procedure of Example 1 was repeated, except that 0.279 g (1.5 mmol) of hexafluorobenzene was used instead of 0.501 g (1.5 mmol) of decafluorobiphenyl to obtain 1.31 g of the fluorine-containing compound. [0105] The resulting fluorine-containing compound has the structural formula of the above formula (3), where the ratio of hydrogen atoms in the cyclic structure of constituent unit A substituted with fluorine atoms is 100% and the ratio of fluorine atoms in constituent unit B is 0%. [0106] The average degree of polymerization as determined by nuclear magnetic resonance spectroscopy was 1.0.

Chem.13 (Example 7) (Synthesis of fluorine-containing compound (n=1) of formula (4) above) [0107] A glass reaction container was filled with 0.805 g (3.0 mmol) of 1,1- bis (4-hydroxyphenyl) cyclohexane (bisphenol Z). The glass reaction container was decompressed to a vacuum and then substituted with nitrogen. Next, 10 mL of DMAc and 0.759 g (7.5 mmol) of triethylamine were added to the glass reaction container. The reaction mixture was cooled to 0°C while stirring. After cooling, 0.318 g (1.5 mmol) of octafluorocyclopentene was added to the glass reaction container. The mixture was cooled to 0°C and stirred for 2 hours, then cooling was stopped and the mixture was stirred at room temperature for 24 hours. Furthermore, the reaction mixture was heated to 80 °C while stirring for 24 hours. Upon completion of heating, the reaction mixture was cooled to room temperature. The reaction mixture was subsequently poured into 0.5 L of pure water. The reaction mixture was suction filtered and the obtained solid was washed with pure water and methanol. After washing, the solid fraction was dried under reduced pressure to obtain 1.52 g of intermediate product. [0108] A glass reaction container was filled with the resulting intermediate product and 0.912 g (6.6 mmol) of potassium carbonate. The glass reaction container was decompressed to a vacuum and then substituted with nitrogen. Next, 10 mL of DMAc and 0.854 g (4.4 mmol) of 2,3,4,5,6-pentafluorostyrene were added to the glass reaction container. The reaction mixture was shielded from light, heated to 80°C with stirring, and then stirred for 15 hours. Upon completion of heating, the reaction mixture was cooled to room temperature. The reaction mixture was subsequently poured into 0.5 L of pure water. The reaction mixture was suction filtered and the obtained solid was washed with pure water and methanol. After washing, the solid fraction was dried under reduced pressure to obtain 1.72 g of a fluorine-containing compound. [0109] The resulting fluorine-containing compound has the structural formula of the above formula (4), where the ratio of hydrogen atoms in the cyclic structure of constituent unit A substituted with fluorine atoms is 100% and the ratio of fluorine atoms in constituent unit B is 0%. [0110] The average degree of polymerization as determined by nuclear magnetic resonance spectroscopy was 1.0. Chem.14 (Example 8) (Synthesis of fluorine-containing compound (n=1) of formula (5) above) [0111] The procedure of Example 1 was repeated, except that 0.408 g (1.5 mmol) of octafluoronaphthalene was used instead of 0.501 g (1.5 mmol) of decafluorobiphenyl to obtain 1.49 g of the fluorine-containing compound. [0112] The resulting fluorine-containing compound has the structural formula of the above formula (5), where the ratio of hydrogen atoms in the cyclic structure of constituent unit A substituted with fluorine atoms is 100% and the ratio of fluorine atoms in constituent unit B is 0%. [0113] The average degree of polymerization as determined by nuclear magnetic resonance spectroscopy was 1.0. Chem.15 (Example 9) (Synthesis of fluorine-containing compound (n=1) of formula (11) above) [0114] The procedure of Example 1 was repeated except that 0.889 g (3.0 mmol) of 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane was used instead of 0.805 g of 1,1-bis(4-hydroxyphenyl)cyclohexane (bisphenol Z). As a result, 1.68 g of fluorine-containing compound was obtained. [0115] The resulting fluorine-containing compound had the structural formula of the above formula (11), where the ratio of hydrogen atoms substituted with fluorine atoms in the cyclic structure of constituent unit A was 100% and the ratio of fluorine atoms in constituent unit B was 0%. [0116] The average degree of polymerization as determined by nuclear magnetic resonance spectroscopy was 1.0. Chem.16 (Example 10) (Synthesis of fluorine-containing compound (n=1) of formula (12) above) [0117] The procedure of Example 1 was repeated except that 0.481 g (3.0 mmol) 1,7-dihydroxynaphthalene was used instead of 0.805 g of 1,1-bis(4- hydroxyphenyl)cyclohexane (bisphenol Z). As a result, 1.33 g of fluorine containing compound was obtained. [0118] The resulting fluorine-containing compound had the structural formula of the above formula (12), where the ratio of hydrogen atoms substituted with fluorine atoms in the cyclic structure of constituent unit A was 100% and the ratio of fluorine atoms in constituent unit B was 0%. [0119] The average degree of polymerization as determined by nuclear magnetic resonance spectroscopy was 1.0. Chem.17 (Example 11) (Synthesis of fluorine-containing compound (n=4) of formula (13) above) [0120] A glass reactor was charged with 1.073 g (4.0 mmol) of 1,1-bis(4- hydroxyphenyl)cyclohexane (bisphenol Z) and 1.216 g (8.8 mmol) of potassium carbonate. The pressure in the glass reaction container was reduced to a vacuum and then the gas inside the container was substituted with nitrogen. Next, 10 mL of DMAc, 0.558 g (3.0 mmol) of hexafluorobenzene, and 0.305 g (2.0 mmol) of chloromethylstyrene (m-, p- mixture) were added to the glass reactor. The reaction mixture was shielded from light, heated to 80°C with stirring, and then stirred for 15 hours. Upon completion of heating, the reaction mixture was cooled to room temperature. The reaction mixture was subsequently poured into 0.5 L of pure water. The reaction mixture was suction filtered and the obtained solid was washed with pure water and methanol. After washing, the solid fraction was dried under reduced pressure to obtain 1.60 g of a fluorine-containing compound. [0121] The resulting fluorine containing compound has the structural formula of the above formula (13), where the ratio of hydrogen atoms in the cyclic structure of constituent unit A substituted with fluorine atoms was 100% and the ratio of fluorine atoms in constituent unit B was 0%. [0122] The average degree of polymerization as determined by nuclear magnetic resonance spectroscopy was 4.0. Chem.18 (Comparative Example 1) (Synthesis of fluorine-containing compound (n=1) of formula (14) above) [0123] The procedure of Example 1 was repeated except that 0.990 g (3.0 mmol) of octafluoro-4,4'-biphenol was used instead of 0.805 g of 1,1-bis(4- hydroxyphenyl)cyclohexane (bisphenol Z). As a result, 1.05 g of a fluororesin compound was obtained. [0124] The resulting fluorine-containing compound had the structural formula of the above formula (14), where the ratio of hydrogen atoms substituted with fluorine atoms in the cyclic structure of constituent unit A was 100% and the ratio of fluorine atoms in constituent unit B was 36%. [0125] The average degree of polymerization as determined by nuclear magnetic resonance spectroscopy was 1.0. (Comparative Example 2) [0126] The procedure of Example 1 was repeated, except that 0.990 g (3.0 mmol) of octafluoro-4,4'-biphenol was used instead of 0.805 g of 1,1-bis(4- hydroxyphenyl)cyclohexane (bisphenol Z) and 0.279 g (1.5 mmol) of hexafluorobenzene was used instead of 0.501 g of decafluorobiphenyl. [0127] However, the synthetic reaction did not proceed and unreacted raw material was recovered. [0128] Note that if the reaction proceeds, the ratio of hydrogen atoms substituted with fluorine atoms in the cyclic structure of the constituent unit A in the resulting fluorine-containing compound is 100%, and the ratio of fluorine atoms in constituent unit B is assumed to be 36%. Chem.19 (Comparative Example 3) (Synthesis of fluorine-containing compound (n=1) of formula (15) above) [0129] A glass reactor was charged with 0. 636g (3.0 mmol) of 2,2,3,3,4,4-hexafluoro-1,5-pentanediol, and 0.501g (1.5 mmol) of decafluorobiphenyl. The pressure in the glass reaction container was reduced to a vacuum and then the gas inside the container was substituted with nitrogen. Next, 10 mL of DMAc and 0.582 g (3.0 mmol) of 2,3,4,5,6- pentafluorostyrene were added to the glass reaction container. The reaction mixture was cooled to 0°C while stirring, 0.300 g (7.5 mmol) of sodium hydride (oil-based, about 60%) was added, and stirred for 1 hour. Subsequently, the reaction mixture was allowed to return to room temperature and stirred for 15 hours.0.05 L of pure water was added to the reaction mixture to stop the reaction, followed by extraction with ethyl acetate. The extracted organic layer was filtered and concentrated under reduced pressure to obtain 0.928 g of a fluorine-containing compound. [0130] The resulting fluorine-containing compound had the structural formula of the above formula (15), where the ratio of hydrogen atoms substituted with fluorine atoms in the cyclic structure of constituent unit A was 100% and the ratio of fluorine atoms in constituent unit B was 35%. [0131] The average degree of polymerization as determined by nuclear magnetic resonance spectroscopy was 1.0. (Comparative Example 4) Polyphenylene Ether (PPE) Resin [0132] As a control for the performance of the fluorine-containing compounds of the present invention, various measurements were also performed on polyphenylene ether (PPE) resin (NORYL SA9000 available from SABIC), which is commonly used as a substrate material for high-frequency transmission. (Evaluation 1: Solvent solubility and thermosetting evaluation (gel fraction)) [0133] 0.5 g of each of the fluorine-containing compounds obtained in Examples 1 to 11 and the PPE resin were weighed, toluene was added, and the mixture heated to 80°C while mixing. If a solution containing 50 mass% of toluene was obtained, the mixture was deemed to be soluble. [0134] All of the obtained solutions were taken into aluminum cups and heated and dried at 200°C for 2 hours using a thermostatic oven (SPHH-102 available from ESPEC CORP.) to obtain a thermoset product. The thermoset product was removed from the aluminum cup and the weight was measured. A 9 mL sample tube was filled with 5 g of methyl ethyl ketone (MEK) and the cured product, and the cured product was immersed in MEK for 24 hours. Thereafter, the solvent was volatilized, washed with MEK, and the thermoset product was dried. The mass after drying was measured and the mass of the dried cured product after MEK immersion was calculated. [0135] The gel fraction was calculated as mass of dried cured product after MEK immersion / mass of cured product before MEK immersion x 100 (%). The obtained results are shown in Table 1. (Evaluation 2 : Electrical properties) [Preparation of varnish-like composition] [0136] The fluorine-containing compounds obtained in Examples 1 to 11 and the PPE resin were dissolved in toluene in the same manner as described above to obtain a 50 mass% solution. Furthermore, Perbutyl (registered trademark) P (available from NOF Corporation) was added as a reaction initiator to 2 mass% with respect to the fluorine-containing compound or PPE resin to obtain a varnish-like composition. [Preparation of pre-preg] [0137] Each varnish-like composition obtained by the method described above was dripped onto a 7 cm × 7 cm piece of glass cloth piece (L2-1078 available from Asahi Kasei Corporation) and then uniformly impregnated. Thereafter, the impregnated material was then dried at 110°C for 10 minutes to obtain a pre-preg. [Preparation of copper clad laminated sheet] [0138] The pre-preg obtained by the method described above was cut to 5 cm x 5 cm, and together with an electrolytic copper foil (thickness: 18 µm) (HVLP available from Furukawa Electric Co., Ltd.), the temperature was raised to 200°C while reducing the pressure using a vacuum hot press machine (manual hydraulic vacuum heating press IMC-4900 available from Imoto Machinery Co., Ltd.), and the pre-preg and copper foil were further adhered by pressing at 200°C for 120 minutes at 4 MPa. [0139] The copper foil of the copper clad laminated sheet was peeled off with tweezers and cut into 4 cm x 4 cm test pieces, and the dielectric constant and dielectric tangent were measured using a vector network analyzer (KEYSIGHT 5247B) using the split cylinder method under 28 GHz, 25°C conditions. The obtained results are shown in Table 1.

Table 1

[0140] The results of Table 1 show that the fluorine-containing compound of the present invention has excellent solvent solubility and high thermosetting properties (gel fraction); furthermore, the dielectric tangent is greatly reduced in a very large frequency region of 28 GHz compared to PPE resin, which is currently commonly used as a substrate material for high-frequency transmission. The fluorine-containing compounds obtained in Comparative Examples 1 and 3 were insoluble in the solvent, and the other evaluations could not be carried out. (Evaluation 3 : Glass transition temperature) [0141] The copper-clad laminates of Examples 1, 5, 8, and 9, and Comparative Example 4 prepared for the above electrical property evaluation were cut at an angle of 45 degrees to the mesh of the glass cloth, and test pieces of 25 mm (length) x 25 mm (width) were prepared. [0142] Using these test pieces, the following temperature profiles were run using a dynamic viscoelasticity measurement device (DMA ARES-G2, available from TA Instruments) with the frequency set to 1.0 Hz and the strain to 0.1%. (1) Holding the test pieces at 25 C for 60 seconds and then heating them from 25°C to 360°C at a rate of 5°C/min. (2) Maintaining the test pieces at a temperature of 360°C for 60 seconds, and ending the measurement. [0143] The temperature at the peak position of the loss factor (tanδ) versus the temperature in the calculated graph was defined as the glass transition temperature (Tg). The results are shown in Table 2. (Evaluation 4 : Coefficient of thermal expansion (CTE)) [0144] The coefficient of thermal expansion was measured using a test piece fabricated similar to Evaluation 3, using a dynamic viscoelasticity measurement device (DMA ARES-G2 available from TA Instruments). The coefficient of thermal expansion between 240°C and 290°C is shown in Table 2. Table 2

[0145] The results of Table 2 show that the fluorine-containing compounds of the present invention have a high glass transition temperature and have a unique characteristic of being resistant to expansion even in the high temperature region of 240°C to 290°C, which is at or above the glass transition temperature. (Evaluation 5: Flame retardancy) [0146] Test pieces were prepared for Example 5, Example 9 and PPE resin as in Evaluation 2. [0147] A needle flame test was performed on a test piece cut to 2 cm x 2 cm in accordance with IEC 60695-11-5. Table 3

INDUSTRIAL APPLICABILITY [0148] The fluorine-containing compound of the present invention has excellent electrical properties (low dielectric constant and low dielectric tangent), as well as flame retardancy, solvent solubility, and thermosetting (crosslinking) properties. Therefore, it can be used as a substrate material used in electrical apparatuses, electronic apparatuses, and communication apparatuses, and particularly for substrate materials for next-generation high frequencies that enable high-speed and large-capacity transmission.

Claims

Claims 1. A fluorine-containing compound comprising: 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 constituent units A to C are joined together with constituent unit C as the terminus.

2. The fluorine-containing compound according to claim 1, wherein the cyclic structure contained in the constituent unit A is a benzene ring or cyclopentenyl group.

3. The fluorine-containing compound according to claim 1 or 2, wherein the constituent units are bonded in the order C-B-(A-B)_n-C or C-A-(B-A)_n-C (where n is 1 to 4).

4. The fluorine-containing compound according to claim 3, wherein n is 1.

5. The fluorine-containing compound according to claim 1 or claim 2, wherein the constituent unit A has 1 to 3 ring structures including side chains.

6. The fluorine-containing compound according to claim 1 or claim 2, wherein the constituent unit A is any one of the following formulas (A-1) to (A-5). [Chem.1]

7. The fluorine-containing compound according to claim 1 or claim 2, wherein the constituent unit B has 1 to 4 ring structures including side chains.

8. The fluorine-containing compound according to claim 1 or claim 2, wherein the constituent unit B is a bisphenol.

9. The fluorine-containing compound according to claim 1 or claim 2, wherein the constituent unit C contains fluorine.

10. The fluorine-containing compound according to claim 1 or claim 2, wherein the constituent unit C contains a benzene ring.

11. The fluorine-containing compound according to claim 1 or claim 2, wherein the constituent unit C is perfluorostyrene.

12. The fluorine containing compound according to claim 1 or claim 2, wherein a gel fraction of a cured product is 50% or more.

13. The fluorine-containing compound according to claim 1 or claim 2, wherein the cured product has a glass transition temperature of 200°C or higher.