Fluorene compound, resin composition, prepreg, resin-coated film, resin-coated metal foil, metal-clad laminate, and wiring board

Abstract

One aspect of the present application relates to a fluorene compound represented by the following formula (1). In formula (1), R1and R2each independently represent an alkyl group having 2 to 5 carbon atoms, R3and R4each independently represent at least one of an alkenyl group and a group represented by the following formula (2). In formula (2), p represents 0 to 10, R5to R7each independently represent a hydrogen atom or an alkyl group, and Ar represents an arylene group.

Description

Technical Field

[0001] This invention relates to fluorene compounds, resin compositions, prepregs, resin-coated films, resin-coated metal foils, metal foil laminates, and wiring boards. Background Technology

[0002] Examples of fluorene compounds that can be added to materials such as resins include those described in Patent Documents 1 and 2.

[0003] In Patent Document 1, a fluorene compound contained in a polymeric composition polymerized and cured for obtaining a high-frequency substrate is described as having at least one polymerizable unsaturated group in each molecule. According to Patent Document 1, a substrate with excellent dielectric properties (especially low dielectric loss factor) in the high-frequency region and excellent heat resistance is disclosed.

[0004] Patent Document 2 discloses a divinylbenzylfluorene compound in which two substituents are added to the carbon atoms of the aromatic ring in the fluorene structure, and a vinylbenzyl group is added to the carbon atoms of the five-membered ring in the fluorene structure. The substituents are selected from one of the following: halogen atoms, alkyl groups having 1 to 5 carbon atoms, alkoxy groups, thioalkoxy groups, aryl groups having 6 to 30 carbon atoms, and heteroaryl groups having 3 to 30 carbon atoms. According to Patent Document 2, a novel divinylbenzylfluorene compound is disclosed that provides improved properties such as transparency and solubility.

[0005] Sometimes, materials such as resins are required to have high flame retardancy. For example, from a safety perspective, materials used in electrical equipment and electronic components are required to have high flame retardancy. More specifically, substrate materials used to form the insulating layer of wiring boards used in electronic devices are required to have high flame retardancy so that electronic components such as semiconductor devices mounted on them can be used reliably even in high-temperature environments. In addition, sometimes materials such as resins are required to have low dielectric properties such as dielectric loss factor. Specifically, in order to improve signal transmission speed and reduce signal loss during transmission, the substrate materials mentioned above are required to have low dielectric properties such as dielectric loss factor. If the substrate material is used for wiring boards that handle high frequencies, then low dielectric properties are even more required. For these reasons, materials added to resins and other similar materials are required to have excellent flame retardancy and low dielectric properties such as dielectric loss factor.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Publication No. 2003-283076

[0009] Patent Document 2: Japanese Patent Publication No. 2022-167558 Summary of the Invention

[0010] This invention was made in view of the aforementioned circumstances, and its object is to provide a fluorene compound with low relative permittivity and dielectric loss factor and excellent flame retardancy. Furthermore, this invention aims to provide a resin composition containing the fluorene compound, a prepreg obtained using the resin composition, a resin-coated film, a resin-coated metal foil, a metal foil-coated laminate, and a wiring board.

[0011] One aspect of the present invention relates to fluorene compounds represented by the following formula (1).

[0012]

[0013] In formula (1), R1 and R2 each independently represent an alkyl group having 2 to 5 carbon atoms, and R3 and R4 each independently represent an alkenyl group and at least one of the groups shown in formula (2) below.

[0014]

[0015] In formula (2), p represents 0 to 10, R5 to R7 each independently represent a hydrogen atom or an alkyl group, and Ar represents an aryl group.

[0016] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description and accompanying drawings. Attached Figure Description

[0017] Figure 1 This is a schematic cross-sectional view illustrating an example of a prepreg according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic cross-sectional view illustrating an example of a metal foil laminate according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic cross-sectional view illustrating an example of a wiring board according to an embodiment of the present invention.

[0020] Figure 4 This is a schematic cross-sectional view illustrating an example of a resin-coated metal foil according to an embodiment of the present invention.

[0021] Figure 5 This is a schematic cross-sectional view illustrating an example of a resin-coated film according to an embodiment of the present invention.

[0022] Figure 6 The HPLC spectrum represents the synthesis of the fluorene compound involved in Example 1.

[0023] Figure 7 This refers to the fluorene compound involved in Example 1. 1 H-NMR spectrum.

[0024] Figure 8 The HPLC spectrum represents the synthesis of the fluorene compound involved in Example 2.

[0025] Figure 9 This refers to the fluorene compound involved in Example 2. 1 H-NMR spectrum. Detailed Implementation

[0026] The inventors have conducted various studies and found that the above-mentioned objectives can be achieved through the following invention.

[0027] The following describes the embodiments of the present invention, but the present invention is not limited to these embodiments.

[0028] [fluorene compounds]

[0029] The fluorene compound involved in the embodiments of the present invention is the fluorene compound shown in the following formula (1).

[0030]

[0031] In formula (1), R1 and R2 each independently represent an alkyl group having 2 to 5 carbon atoms, and R3 and R4 each independently represent an alkenyl group and at least one of the groups shown in formula (2) below.

[0032]

[0033] In formula (2), p represents 0 to 10, R5 to R7 each independently represent a hydrogen atom or an alkyl group, and Ar represents an aryl group.

[0034] The fluorene compound is a fluorene compound with low relative permittivity and dielectric loss factor, and excellent flame retardancy. This is believed to be based on, for example, the following reasons. The fluorene compound has a fluorene structure as shown in formula (1), and the alkyl group is located at the carbon atom of the 5-membered ring (position 9 of the fluorene structure). Therefore, the low dielectric properties of the fluorene structure can be fully utilized, and the relative permittivity and dielectric loss factor can be significantly reduced. Furthermore, as can be seen from formula (1), the fluorene compound has an unsaturated double bond on the carbon atom of the aromatic ring in the fluorene structure. Therefore, flame retardancy can be improved while maintaining excellent low dielectric properties. In contrast, conventional fluorene compounds are not fluorene compounds that have an alkyl group with 2 to 5 carbon atoms at position 9 of the fluorene structure and an unsaturated double bond on the carbon atom of the aromatic ring in the fluorene structure. For example, as described in Patent Document 2, when an unsaturated double bond such as a vinyl benzyl group is present at the carbon atom of the five-membered ring of the fluorene structure (at the 9th position of the fluorene structure), the fluorene structure is considered to have poor flame retardancy because it exists on the side chain. Furthermore, since it does not have an alkyl group with 2 to 5 carbon atoms at the 9th position of the fluorene structure, it is considered that its low dielectric properties cannot be fully utilized. Therefore, the fluorene compound described above has a lower relative permittivity and dielectric loss factor, and superior flame retardancy compared to conventional fluorene compounds.

[0035] In formula (1), R1 and R2 are independent. That is, R1 and R2 can be the same group or different groups. R1 and R2 represent alkyl groups having 2 to 5 carbon atoms. R3 and R4 are independent. That is, R3 and R4 can be the same group or different groups. R3 and R4 represent at least one of alkenyl groups and groups shown in formula (2) below.

[0036] The alkyl group in formula (1) is not particularly limited as long as it has 2 to 5 carbon atoms, and examples include ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, and pentyl. The alkyl group is preferably butyl.

[0037] The alkenyl group in formula (1) is not particularly limited, and examples include alkenyl groups with 2 to 5 carbon atoms. Specifically, examples of alkenyl groups include vinyl, allyl, propenyl and butenyl, among which vinyl is preferred.

[0038] In formula (2), p represents 0 to 10. R5 to R7 are independent. That is, R5 to R7 can be the same group or different groups. R5 to R7 represent hydrogen atoms or alkyl groups. Ar represents aryl groups.

[0039] It should be noted that in the above formula (2), when p is 0, it means that Ar (arylene) is directly bonded to the aromatic ring of the fluorene structure.

[0040] The alkyl group in formula (2) is not particularly limited, but is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specifically, examples include methyl, ethyl, propyl, hexyl, and decyl.

[0041] The arylene group in formula (2) is not particularly limited. Examples of such arylene groups include monocyclic aromatic groups such as phenylene; and polycyclic aromatic groups such as naphthalene rings, which are not monocyclic. In addition, the arylene group may also include derivatives in which the hydrogen atoms bonded to the aromatic ring are replaced by functional groups such as alkenyl, alkynyl, formyl, alkyl carbonyl, alkenyl carbonyl, or alkynyl carbonyl.

[0042] Preferred examples of the group represented by formula (2) include vinylphenyl as shown in formula (5) and vinylbenzyl (ethylene benzyl) as shown in formula (6), wherein vinylphenyl as shown in formula (5) is preferred. In addition, examples of vinylbenzyl include o-vinylbenzyl, p-vinylbenzyl and meta-vinylbenzyl.

[0043]

[0044]

[0045] Specifically, examples of fluorene compounds include those shown in formula (3) and those shown in formula (4). The fluorene compound may be either the fluorene compound shown in formula (3) or the fluorene compound shown in formula (4), or it may be a fluorene compound comprising at least one of the fluorene compounds shown in formula (3) and the fluorene compounds shown in formula (4).

[0046]

[0047]

[0048] The dielectric loss factor of the fluorene compound at a frequency of 1 GHz is preferably 0.00001 to 0.002, more preferably 0.00001 to 0.001, and even more preferably 0.00001 to 0.0005. That is, the fluorene compound is preferably the fluorene compound shown in formula (1) and the dielectric loss factor is within the range of that range. The relative permittivity of the fluorene compound at a frequency of 1 GHz is preferably 2 to 3.5, more preferably 2 to 3. That is, the fluorene compound is preferably the fluorene compound shown in formula (1) and the relative permittivity is within the range of that range. The relative permittivity and dielectric loss factor here are the relative permittivity and dielectric loss factor at a frequency of 1 GHz, and examples include the relative permittivity and dielectric loss factor at a frequency of 1 GHz measured by the resonant cavity perturbation method.

[0049] Preferably, the fluorene compound is such that the thermal decomposition residue after heating the fluorene compound to 600°C is 26% by mass or more (i.e., 26 to 100% by mass) relative to the fluorene compound before heating. The ratio of the thermal decomposition residue after heating the fluorene compound to 600°C to the fluorene compound before heating can be, for example, in thermogravimetric analysis (TGA), and more specifically, thermogravimetric-differential thermal analysis (TG-DTA), such as the ratio of the residue after heating the fluorene compound to 600°C to the fluorene compound before heating. That is, in thermogravimetric analysis, the weight after heating to 600°C is 26% or more (i.e., 26 to 100%) relative to the weight before heating.

[0050] The fluorene compound can be added to materials such as resins. Since the fluorene compound has a low relative permittivity and dielectric loss factor and excellent flame retardancy, adding it to a material can reduce the relative permittivity and dielectric loss factor and improve flame retardancy. Therefore, the material to which the fluorene compound is added is not particularly limited, but materials that require a reduction in relative permittivity and dielectric loss factor and improved flame retardancy are preferred. Examples of materials to which the fluorene compound is added include materials used in electrical equipment and electronic components, and more specifically, substrate materials used to form the insulating layer of wiring boards used in electronic devices. Furthermore, examples of materials to which the fluorene compound is added include resins and resin compositions. These resins and resin compositions are not particularly limited and can be applied to a wide range of applications. The resin contained in the resin and resin composition can be, for example, a thermoplastic resin, a thermosetting resin, or a mixture thereof. Examples of thermosetting resins include epoxy resins, polyphenylene ether resins, cyanate ester resins, phenolic resins, maleimide compounds, modified polyphenylene ether compounds, styrene-based compounds, polybutadiene-based compounds, styrene-butadiene-based compounds, acrylic compounds, methacrylic acid compounds, and polyfunctional vinyl aromatic copolymers. Examples of polyfunctional vinyl aromatic copolymers include copolymers containing repeating units derived from divinyl aromatic compounds and repeating units derived from monovinyl aromatic compounds. Examples of divinyl aromatic compounds include divinylbenzene, and examples of monovinyl aromatic compounds include styrene, ethylvinylbenzene, and methylstyrene. Examples of thermoplastic resins include polyphenylene sulfide resin, liquid crystal polymer, polyethylene resin, polypropylene resin, polystyrene resin, polyurethane resin, acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylic resin, polyethylene terephthalate resin, polycarbonate resin, polyacetal resin, polyimide resin, polyamide-imide resin, cyclic olefin polymer, cyclic olefin copolymer, and styrene-based elastomers. These resins can be used alone or in combination of two or more. Furthermore, the fluorene compound is preferably used in insulating materials for wiring boards. Specifically, the fluorene compound is preferably contained in prepregs, resin layers of resin-coated metal foils, resin layers of resin-coated films, insulating layers of metal foil laminates, and insulating layers of wiring boards. The insulating materials for wiring boards are required to have low relative permittivity and dielectric loss factor, and excellent flame retardancy. As described above, since the fluorene compound is a fluorene compound with low relative permittivity and dielectric loss factor and excellent flame retardancy, by adding the fluorene compound to the material, the relative permittivity and dielectric loss factor can be reduced and the flame retardancy can be improved, thus it is preferably used in insulating materials for wiring boards.The amount of fluorene compound added is preferably 5 to 70 parts by mass relative to 100 parts by mass of the material (the object to which the fluorene compound is added). More preferably, it is 10 to 50 parts by mass. If the amount of fluorene compound added is too small, the effect of adding the fluorene compound, namely, the effect of reducing the relative permittivity and dielectric loss factor and improving flame retardancy, may not be fully realized. Furthermore, if the amount of fluorene compound added is too large, the properties of the material (properties other than low dielectric properties and flame retardancy) may decrease. In addition, the effect of improving flame retardancy may saturate even if a specified amount or more of the fluorene compound is added. Therefore, as long as the amount of fluorene compound added is within the above range, the relative permittivity and dielectric loss factor can be reduced while suppressing the decrease in the properties of the material, and flame retardancy can be improved.

[0051] [Preparation method of fluorene compounds]

[0052] The method for producing the fluorene compound is not particularly limited as long as it can produce the fluorene compound. Specifically, the method for producing the fluorene compound includes a synthesis method using the reaction shown in the following formula (7).

[0053]

[0054] In formula (7), R1 and R2 are the same as R1 and R2 in formula (1), each independently representing an alkyl group having 2 to 5 carbon atoms. R3 and R4 are the same as R3 and R4 in formula (1), each independently representing an alkenyl group and at least one of the groups shown in formula (2). X1 and X2 each independently represent a halogen atom. Y represents -BF3K, borate group [-B(OH)2], or borate ester group.

[0055] The halogen atom is not particularly limited, and examples include fluorine atom, chlorine atom, bromine atom and iodine atom, among which bromine atom is preferred.

[0056] The borate ester group is not particularly limited, and examples include dioxaborolane group, etc.

[0057] As for R3-Y and R4-Y, there is no particular limitation as long as they are compounds formed by the combination of R3 and R4 with Y. Examples include potassium ethylene trifluoroborate (potassium vinyl trifluoroborate) and 4-vinylphenylboronic acid.

[0058] The catalyst is not particularly limited as long as it is capable of promoting the reaction shown in formula (7). Examples of catalysts include palladium (Pd) catalysts, nickel (Ni) catalysts, and ruthenium (Ru) catalysts. The palladium catalyst is not particularly limited as long as it is capable of promoting the reaction shown in formula (7). Examples of palladium catalysts include tetrakis(triphenylphosphine)palladium(O)[Pd(PPh3)4], [1,1'-bis(diphenylphosphine)ferrocene]palladium(II) dichloromethane adduct [PdCl2(dppf)], and palladium(II) acetate [Pd(OAc)2]. Examples of nickel catalysts include [1,1'-bis(diphenylphosphine)ferrocene]nickel(II) dichloride [NiCl2(dppf)], dichlorobis(triphenylphosphine)nickel(II) [NiCl2(PPh3)2], and bis(1,5-cyclooctadiene)nickel(O) [Ni(cod)2]. Tetra(triphenylphosphine)palladium(O) [Pd(PPh3)4] is preferred as the catalyst.

[0059] The base is not particularly limited as long as it is a catalyst capable of promoting the reaction shown in formula (7). Examples of such bases include carbonate bases such as potassium carbonate, fluoride bases such as cesium fluoride, and amine bases such as tetrabutylammonium hydroxide, among which carbonate bases are preferred, and potassium carbonate is more preferred. The base can also be prepared into an aqueous solution for use.

[0060] The reaction shown in formula (7) can be carried out without a solvent, but it can also be carried out in the presence of a solvent. There are no particular limitations on the solvent, as long as it enables the reaction shown in formula (7) to proceed well. Examples of solvents include tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and toluene, with THF being preferred. Furthermore, the solvent may contain water; for example, a mixture of THF and water is preferred. It should be noted that the water may be the water contained in an aqueous solution of the base.

[0061] As for the conditions of the reaction shown in formula (7), there are no particular limitations as long as the reaction shown in formula (7) proceeds well. For example, the reaction temperature is preferably 50 to 90°C, more preferably 60 to 80°C. In addition, the reaction time is preferably 4 to 8 hours, more preferably 4 to 6 hours.

[0062] As a method for manufacturing the fluorene compound, if the fluorene compound is the fluorene compound shown in formula (3), for example, a method of synthesis by the reaction shown in formula (7) below can be cited.

[0063]

[0064] As a method for manufacturing the fluorene compound, if the fluorene compound is the fluorene compound shown in formula (4), for example, a method of synthesis by the reaction shown in formula (9) below can be cited.

[0065]

[0066] [Prepreg, metal foil laminate, wiring board, resin-coated metal foil, and resin-coated film]

[0067] By using a resin composition obtained by adding the fluorene compound involved in this embodiment to the thermosetting resin, prepregs, metal foil laminates, wiring boards, resin-coated metal foils, and resin-coated films can be obtained as described below.

[0068] (Prepreg)

[0069] Figure 1 This is a schematic cross-sectional view illustrating an example of the prepreg 1 according to an embodiment of the present invention.

[0070] like Figure 1 As shown, the prepreg 1 according to this embodiment includes: the resin composition or the semi-cured product of the resin composition 2; and a fibrous substrate 3. The prepreg 1 includes: the resin composition or the semi-cured product of the resin composition 2; and a fibrous substrate 3 present in the resin composition or the semi-cured product of the resin composition 2.

[0071] It should be noted that, in this embodiment, a semi-cured substance is a substance that has cured the resin composition to a state where it can still be further cured. That is, a semi-cured substance is a substance that causes the resin composition to be in a semi-cured state (benzene curing). For example, if the resin composition is heated, the viscosity initially decreases slowly, then begins to cure, and the viscosity slowly increases. In this case, the state from the start of the viscosity increase until complete curing can be listed as a semi-cured substance.

[0072] As a prepreg obtained using the resin composition according to this embodiment, it can be a prepreg containing a semi-cured product of the resin composition, as described above. Alternatively, it can be a prepreg containing an uncured resin composition. That is, it can be a prepreg containing a semi-cured product of the resin composition (the resin composition of stage B) and a fibrous substrate, or it can be a prepreg containing the resin composition before curing (the resin composition of stage A) and a fibrous substrate. Furthermore, the resin composition or the semi-cured product of the resin composition can be a substance obtained by drying or heating the resin composition.

[0073] In manufacturing the prepreg, the resin composition 2 is mostly formulated into a varnish-like form for impregnation into the fibrous substrate 3 used to form the prepreg. That is, the resin composition 2 is typically a resin varnish formulated into a varnish-like form. This varnish-like resin composition (resin varnish) can be formulated, for example, in the following manner.

[0074] First, the components soluble in the organic solvent are added to the organic solvent and dissolved. Heating may be performed at this time if necessary. Then, the components insoluble in the organic solvent are added as needed, and the mixture is dispersed to a specified dispersion state using a ball mill, bead mill, planetary mixer, roller mill, etc., thereby preparing a varnish-like resin composition. The organic solvent used herein is not particularly limited, as long as it can dissolve the resin composition and does not hinder the curing reaction. Specifically, examples include toluene and methyl ethyl ketone (MEK).

[0075] Specifically, examples of the fibrous substrate include glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and cotton linter paper. It should be noted that using glass cloth results in a laminate with excellent mechanical strength, and glass cloth that has undergone a flattening process is particularly preferred. Specifically, the flattening process can be exemplified by continuously applying appropriate pressure to the glass cloth using pressure rollers to compress the yarn into a flat shape. It should be noted that the thickness of the fibrous substrate is typically between 0.01 mm and 0.3 mm. Furthermore, the glass fibers constituting the glass cloth are not particularly limited, and examples include Q glass, NE glass, E glass, S glass, T glass, L glass, and L2 glass. Additionally, the surface of the fibrous substrate can be surface-treated with a silane coupling agent. The silane coupling agent is not particularly limited, and examples include silane coupling agents that have at least one selected from the group consisting of vinyl, acryloyl, methacryl, styrene, amino, and epoxy groups within the molecule.

[0076] The method for manufacturing the prepreg is not particularly limited as long as it can produce the prepreg. Specifically, when manufacturing the prepreg, the resin composition involved in this embodiment described above is mostly formulated into a varnish-like form and used as a resin varnish.

[0077] Specifically, a method for manufacturing prepreg 1 may include: impregnating the resin composition 2 (e.g., a resin composition 2 formulated into a varnish-like state) into a fibrous substrate 3 and then drying it. The impregnation of the resin composition 2 into the fibrous substrate 3 is carried out by impregnation and coating, etc. Impregnation can be repeated multiple times as needed. Furthermore, the final desired composition and impregnation amount can be adjusted by repeatedly impregnating with various resin compositions of different compositions and concentrations.

[0078] The fibrous substrate 3 impregnated with the resin composition (resin varnish) 2 is heated under conditions varying depending on the required heating conditions and the resin composition, for example, at 40°C or higher and 180°C or lower for 1 minute or more and 10 minutes or less. Heating yields a prepreg 1 in a pre-cured (stage A) or semi-cured (stage B) state. It should be noted that the heating causes the organic solvent to evaporate from the resin varnish, thus reducing or eliminating the organic solvent.

[0079] (Metal foil laminate)

[0080] Figure 2 This is a schematic cross-sectional view illustrating an example of a metal foil laminate 11 according to an embodiment of the present invention.

[0081] like Figure 2 As shown, the metal-clad laminate 11 according to this embodiment includes: an insulating layer 12 comprising a cured product of the resin composition; and a metal foil 13 disposed on the insulating layer 12. Examples of metal-clad laminates 11 include those comprising... Figure 1 The insulating layer 12 is a cured prepreg 1; and a metal foil laminate with a metal foil 13 laminated together with the insulating layer 12. Furthermore, the insulating layer 12 can be formed from a cured resin composition or from a cured prepreg. The thickness of the metal foil 13 varies depending on the required performance of the final wiring board and is not particularly limited. The thickness of the metal foil 13 can be appropriately set according to the desired purpose, and is preferably 0.2 to 70 μm. Examples of metal foil 13 include copper foil and aluminum foil; in the case of a thinner metal foil, a carrier-supported copper foil with a release layer and a carrier can be used to improve operability.

[0082] As for the method of manufacturing the metal-clad laminate 11, there is no particular limitation as long as the metal-clad laminate 11 can be manufactured. Specifically, a method of using the prepreg 1 to manufacture the metal-clad laminate 11 can be cited. As a method, a method can be cited that involves taking one piece of the prepreg 1 or overlapping several pieces of the prepreg 1, and then overlapping a metal foil 13 such as copper foil on its upper and lower surfaces or one side surface, and heating and pressing the metal foil 13 and the prepreg 1 to form an integral laminate, thereby producing a laminate 11 with metal foil on both sides or one side surface. That is, the metal-clad laminate 11 is obtained by laminating the metal foil 13 on the prepreg 1 and heating and pressing it. In addition, the heating and pressing conditions can be appropriately set according to the thickness of the metal-clad laminate 11 or the type of resin composition contained in the prepreg 1. Depending on the resin composition, for example, the temperature can be set to 170–230°C, the pressure to 0.5–5 MPa, and the time to 60–150 minutes. Furthermore, the metal foil laminate can also be manufactured without using prepreg. Examples include methods such as coating a varnish-like resin composition onto a metal foil, forming a layer containing the resin composition on the metal foil, and then subjecting it to heating and pressure.

[0083] (Wiring board)

[0084] Figure 3 This is a schematic cross-sectional view illustrating an example of a wiring board 21 according to an embodiment of the present invention.

[0085] like Figure 3 As shown, the wiring board 21 according to this embodiment includes: an insulating layer 12 comprising a cured product of the resin composition; and wiring 14 disposed on the insulating layer 12. Examples of wiring boards 21 include those comprising... Figure 1 The insulating layer 12 used after curing the prepreg 1 shown; and the wiring board 14 formed by laminating the insulating layer 12 together and removing a portion of the metal foil 13, etc. Furthermore, the insulating layer 12 can be formed from a cured product of the resin composition or from a cured product of the prepreg.

[0086] The method for manufacturing the wiring board 21 is not particularly limited as long as it can be manufactured. Specifically, methods such as using the prepreg 1 to manufacture the wiring board 21 can be listed. As a method, for example, etching the metal foil 13 on the surface of the metal foil laminate 11 manufactured as described above to form wiring, thereby manufacturing a wiring board 21 with wiring as a circuit on the surface of the insulating layer 12. That is, the wiring board 21 can be obtained by removing a portion of the metal foil 13 on the surface of the metal foil laminate 11 to form a circuit. In addition, as a method for forming a circuit, besides the methods described above, methods such as forming a circuit by a semi-additive process (SAP) or a modified semi-additive process (MSAP) can be listed.

[0087] (Resin-coated metal foil)

[0088] Figure 4 This is a schematic cross-sectional view showing an example of the resin-coated metal foil 31 involved in this embodiment.

[0089] like Figure 4 As shown, the resin-coated metal foil 31 according to this embodiment includes: a resin layer 32 comprising the resin composition or a semi-cured product of the resin composition; and a metal foil 13. The resin-coated metal foil 31 has the metal foil 13 on the surface of the resin layer 32. That is, the resin-coated metal foil 31 includes: the resin layer 32; and the metal foil 13 laminated together with the resin layer 32. Furthermore, the resin-coated metal foil 31 may also have other layers between the resin layer 32 and the metal foil 13.

[0090] The resin layer 32 may contain a semi-cured form of the resin composition as described above, or it may contain uncured resin composition. That is, the resin-coated metal foil 31 may be a resin layer comprising a semi-cured form of the resin composition (the resin composition of stage B) and a resin-coated metal foil, or it may be a resin layer comprising a resin composition before curing (the resin composition of stage A) and a resin-coated metal foil. Furthermore, the resin layer may or may not contain a fibrous substrate, as long as it contains the resin composition or a semi-cured form of the resin composition. Furthermore, the resin composition or the semi-cured form of the resin composition may be a substance obtained by drying or heating the resin composition. Furthermore, the same material as the fibrous substrate of the prepreg may be used as the fibrous substrate.

[0091] The metal foil can be any type of metal foil, including metal foil laminates and resin-coated metal foils. Examples of such metal foils include copper foil and aluminum foil.

[0092] The resin-coated metal foil 31 may be equipped with a cover film or the like as needed. The cover film helps prevent the introduction of foreign matter. The cover film is not particularly limited, and examples include polyolefin films, polyester films, polymethylpentene films, and films formed by applying a release agent layer to these films.

[0093] The method for manufacturing the resin-coated metal foil 31 is not particularly limited as long as it can produce the resin-coated metal foil 31. Examples of methods for manufacturing the resin-coated metal foil 31 include coating a varnish-like resin composition (resin varnish) onto a metal foil 13 and then heating it. For example, the varnish-like resin composition can be coated onto the metal foil 13 using a doctor blade coater. The coated resin composition varies depending on the resin composition, and for example, it is heated at a temperature of 40°C or higher and 180°C or lower, for a time of 0.1 minutes or higher and 10 minutes or lower. The heated resin composition forms an uncured resin layer 32 on the metal foil 13. It should be noted that by heating, the organic solvent evaporates from the resin varnish, thus reducing or removing the organic solvent.

[0094] (Resin-coated membrane)

[0095] Figure 5 This is a schematic cross-sectional view showing an example of the resin-coated membrane 41 according to this embodiment.

[0096] like Figure 5 As shown, the resin-bearing membrane 41 according to this embodiment includes: a resin layer 42 comprising the resin composition or a semi-cured product of the resin composition; and a support membrane 43. The resin-bearing membrane 41 includes: the resin layer 42; and the support membrane 43 laminated together with the resin layer 42. Furthermore, the resin-bearing membrane 41 may also have other layers between the resin layer 42 and the support membrane 43.

[0097] The resin layer 42 may contain a semi-cured form of the resin composition as described above, or it may contain uncured resin composition. That is, the resin-bearing membrane 41 may be a resin layer comprising: a semi-cured form of the resin composition (the resin composition of stage B); and a resin-bearing membrane supporting the membrane; or it may be a resin layer comprising: a resin composition before curing (the resin composition of stage A); and a resin-bearing membrane supporting the membrane. Furthermore, the resin layer may or may not contain a fibrous substrate, as long as it contains the resin composition or a semi-cured form of the resin composition. Furthermore, the resin composition or the semi-cured form of the resin composition may be a substance obtained by drying or heating the resin composition. Furthermore, the same material as the fibrous substrate of the prepreg may be used as the fibrous substrate.

[0098] As the support film 43, the support film used in resin-impregnated films can be used without limitation. Examples of such support films include electrically insulating films such as polyester films, polyethylene terephthalate (PET) films, polyimide films, polyethylene urea films, polyetheretherketone films, polyphenylene sulfide films, polyamide films, polycarbonate films, and polyarylate films.

[0099] The resin-coated membrane 41 may be equipped with a cover film or the like as needed. The cover film helps prevent the introduction of foreign matter. The cover film is not particularly limited, and examples include polyolefin films, polyester films, and polymethylpentene films.

[0100] The supporting film and the covering film can be films that have undergone surface treatments such as matte treatment, corona treatment, demolding treatment and roughening treatment as needed.

[0101] The method for manufacturing the resin-containing film 41 is not particularly limited as long as it is possible to manufacture the resin-containing film 41. Examples of methods for manufacturing the resin-containing film 41 include, for instance, coating the aforementioned varnish-like resin composition (resin varnish) onto a support film 43 and then heating it. For example, the varnish-like resin composition can be coated onto the support film 43 using a doctor blade coater. The coated resin composition varies depending on the resin composition, and for example, it is heated at a temperature of 40°C or higher and 180°C or lower, for a time of 0.1 minutes or higher and 10 minutes or lower. The heated resin composition forms an uncured resin layer 42 on the support film 43. It should be noted that the heating causes the organic solvent to evaporate from the resin varnish, thus reducing or removing the organic solvent.

[0102] After curing the resin composition containing the fluorene compound according to this embodiment, a cured product with low relative permittivity and dielectric loss factor and excellent flame retardancy can be obtained. Therefore, the prepreg, after curing, becomes a cured product with low relative permittivity and dielectric loss factor and excellent flame retardancy. The resin-coated metal foil and the resin-coated film are resin-coated metal foils and resin-coated films having resin layers that, when cured separately, become insulating layers containing the cured product. The metal-coated foil laminate and the wiring board are metal-coated foil laminates and wiring boards respectively having insulating layers containing the cured product. The prepreg, the resin-coated film, the resin-coated metal foil, and the metal-coated foil laminate can be used to properly manufacture the wiring board, for example, they can also be used to manufacture multilayer wiring boards. For example, if it is the resin-coated film, a multilayer wiring board can be manufactured by peeling off the support film after laminating it on the wiring board, or by peeling off the support film and then laminating it on the wiring board. If the metal foil is resin-impregnated, a multilayer wiring board can be manufactured, for example, by laminating it onto a wiring board. As described above, by using the resin-impregnated film and the resin-impregnated metal foil, a multilayer wiring board having an insulating layer containing the cured material can be manufactured.

[0103] This specification discloses the techniques of various embodiments as described above, and the main technical features are summarized below.

[0104] The fluorene compound involved in the first technical solution of the present invention is the fluorene compound shown in formula (1).

[0105] The fluorene compound involved in the second technical solution of the present invention is in the fluorene compound involved in the first technical solution of the present invention, wherein the fluorene compound represented by formula (1) includes at least one of the fluorene compound represented by formula (3) and the fluorene compound represented by formula (4).

[0106] The fluorene compound involved in the third technical solution of the present invention has a dielectric loss factor of 0.00001 to 0.001 at a frequency of 1 GHz, which is the same as that involved in the first or second technical solution of the present invention.

[0107] In the fourth technical solution of the present invention, the fluorene compound involved in any one of the first to third technical solutions of the present invention has a weight of 26% or more after heating to 600°C in thermogravimetric analysis compared with the weight before heating.

[0108] The fifth technical solution of the present invention relates to a resin composition containing the fluorene compound and thermosetting resin involved in any one of the technical solutions of the first to fourth technical solutions of the present invention.

[0109] The sixth technical solution of the present invention relates to a prepreg comprising: the resin composition or a semi-cured product of the resin composition according to the fifth technical solution of the present invention; and a fibrous substrate.

[0110] The seventh technical solution of the present invention relates to a resin-containing membrane, comprising: a resin layer containing the resin composition or a semi-cured product of the resin composition according to the fifth technical solution of the present invention; and a support membrane.

[0111] The eighth technical solution of the present invention relates to a resin-coated metal foil, comprising: a resin layer containing the resin composition or a semi-cured product of the resin composition according to the fifth technical solution of the present invention; and a metal foil.

[0112] The ninth technical solution of the present invention relates to a metal foil laminate, comprising: an insulating layer comprising a cured resin composition according to the fifth technical solution of the present invention; and a metal foil.

[0113] The tenth technical solution of the present invention relates to a metal foil laminate, comprising: an insulating layer comprising a cured prepreg of the sixth technical solution of the present invention; and a metal foil.

[0114] The eleventh technical solution of the present invention relates to a wiring board, comprising: an insulating layer comprising a cured resin composition according to the fifth technical solution of the present invention; and wiring.

[0115] The 12th technical solution of the present invention relates to a wiring board, which includes: an insulating layer comprising a cured prepreg of the 6th technical solution of the present invention; and wiring.

[0116] According to the present invention, fluorene compounds with low relative permittivity and dielectric loss factor and excellent flame retardancy can be provided. Furthermore, according to the present invention, resin compositions containing the fluorene compounds, prepregs obtained using the resin compositions, resin-coated films, resin-coated metal foils, metal-coated laminates, and wiring boards can be provided.

[0117] The present invention will be further described in detail below through embodiments; however, the scope of the present invention is not limited to these embodiments.

[0118] Example

[0119] [Example 1, Example 2, and Comparative Examples 1-3]

[0120] (Example 1)

[0121] The synthesis of the fluorene compound involved in Example 1 will be described.

[0122] The fluorene compound shown in formula (3) was synthesized as shown in formula (8).

[0123] Specifically, first, a 200 mL three-necked flask equipped with a water bath, a magnetic stirrer, and a cooling tube was prepared. 5.1 g (approximately 12.5 mmol) of compound (2,7-dibromo-9,9-dipropylfluorene, molecular weight: 408), 5.0 g (approximately 37.3 mmol) of compound (potassium ethylenetrifluoroborate, molecular weight: 134), and 80 mL of tetrahydrofuran (THF) were added to the three-necked flask, followed by argon purging. Then, 0.6 g (approximately 0.052 mmol) of tetrakis(triphenylphosphine)palladium(O)[Pd(PPh3)4] (molecular weight: 1156) was added to the argon-purged flask. The liquid in the three-necked flask was then stirred by rotating the stir bar of the magnetic stirrer. A K2CO3 aqueous solution (approximately 4.7 mol / L) was prepared by adding 5.16 g (approximately 37.4 mmol) of potassium carbonate (K2CO3, molecular weight: 138) to 8 mL of distilled water (043-16785 manufactured by Fujifilm and Koujun Chemical Co., Ltd.). This K2CO3 aqueous solution was added to the three-necked flask and stirred at reflux temperature (70°C) for 5 hours. The reaction shown in formula (8) was carried out by this operation. The reaction solution obtained by this stirring was cooled to room temperature, and after removing the aqueous phase from the reaction solution, magnesium sulfate (MgSO4) was added to the three-necked flask to dry the organic phase. Then, THF was removed by distillation. The solid obtained by this operation was dissolved in a mixed solvent of toluene and heptane in a volume ratio of 1:1, and separated twice by silica gel column chromatography (silica gel: Merck 1.09385.5000), using the mixed solvent (toluene and heptane) as the elution solvent. The fraction containing the target substance was dried using a rotary evaporator at 70°C. The resulting solid was then dried at 70°C and 100 Pa for 1 hour. This yielded 2.7 g of a white solid.

[0124] The purity of the obtained solid was determined by high-performance liquid chromatography (HPLC) under the following conditions: column: ZORBAX RX-SiL (normal phase) manufactured by Agilent Technologies, Inc.; eluent: a 1:1 mass ratio of toluene and ethyl acetate; flow rate: 1.0 m / min; observation wavelength: 300 nm. The results (HPLC chromatograms) are shown below. Figure 6 By this Figure 6 It can be seen that the purity is approximately 99.4%. It should be noted that... Figure 6 The HPLC chromatogram of the fluorene compound involved in Example 1 is shown. The vertical axis represents intensity (mAU) and the horizontal axis represents elution time (minutes).

[0125] Furthermore, adopt 1 The obtained solid was analyzed by ¹H-NMR at 400 MHz using CD₂Cl₂ (containing 0.05% by mass trimethylsilane (TMS)). The results obtained from this analysis... 1 H-NMR spectrum (of the obtained solid) 1 The H-NMR spectrum is shown in Figure 7 According to the results obtained 1 The H-NMR spectrum shows that the solid is the fluorene compound represented by formula (3). Specifically, in the obtained 1 In the H-NMR spectrum, peak 71 near chemical shift δ7-8 is the hydrogen peak of the aromatic ring in the fluorene compound represented by formula (3); peak 72 near chemical shift δ5-7 is the hydrogen peak of the vinyl group in the fluorene compound represented by formula (3); peak 73 near chemical shift δ2 and near chemical shift δ0.5-1 is the hydrogen peak of the propyl group in the fluorene compound represented by formula (3), thus confirming that the solid is the fluorene compound represented by formula (3). It should be noted that peak 74 near chemical shift δ1.5 is a water-based peak, and peak 75 near chemical shift δ0 is a TMS-based peak. It should be noted that... Figure 7 The fluorene compound involved in Example 1 is shown. 1 H-NMR spectrum, with the vertical axis representing intensity and the horizontal axis representing chemical shift δ.

[0126] Since the molecular weight of the fluorene compound shown in formula (3) is 302 and the purity is about 99.4%, the yield of the fluorene compound shown in formula (3) in this reaction is about 71%.

[0127] (Example 2)

[0128] The synthesis of the fluorene compound involved in Example 2 will be described.

[0129] The fluorene compound shown in formula (4) was synthesized as shown in formula (9).

[0130] Specifically, first, a 200 mL three-necked flask equipped with a water bath, a magnetic stirrer, and a cooling tube was prepared. 4.6 g (approximately 11.3 mmol) of compound (2,7-dibromo-9,9-dipropylfluorene, molecular weight: 408), compound (4-vinylphenylboronic acid, molecular weight: 148), 5.0 g (approximately 33.8 mmol) of compound (B-2), and 80 mL of tetrahydrofuran (THF) were added to the three-necked flask, followed by argon purging. Then, 0.6 g (approximately 0.052 mmol) of tetrakis(triphenylphosphine)palladium(O)[Pd(PPh3)4] (molecular weight: 1156) was added to the argon-purged flask. The liquid in the three-necked flask was then stirred by rotating the stir bar of the magnetic stirrer. 4.67 g (approximately 33.8 mmol) of potassium carbonate (K₂CO₃, molecular weight: 138) was added to 16 mL of distilled water (043-16785 manufactured by Fujifilm and Koujun Pharmaceutical Co., Ltd.) to prepare an aqueous solution of K₂CO₃ (approximately 2.1 mol / L). This aqueous solution of K₂CO₃ was added to the three-necked flask and stirred at reflux temperature (70°C) for 5 hours. The reaction shown in formula (9) was carried out by this operation. The reaction solution obtained by this stirring was cooled to room temperature, and after removing the aqueous phase from the reaction solution, magnesium sulfate (MgSO₄) was added to the three-necked flask to dry the organic phase. Then, THF was removed by distillation. The solid obtained by this operation was dissolved in toluene at 70°C and separated twice by silica gel column chromatography (silica gel: 1.09385.5000 manufactured by Merck), using toluene as the eluent. The fraction containing the target substance was dried using a rotary evaporator at 70°C. The obtained solid was resuspended and washed once each with 50 mL of ethanol and 50 mL of heptane. Then, the resuspended and washed solid was dissolved in a small amount of toluene at 70°C, and precipitated again by gradually adding heptane. The solid obtained from this second precipitation was dissolved in a small amount of toluene at 70°C, and precipitated again by gradually adding heptane. That is, two precipitation cycles were performed. The solid obtained after two precipitation cycles was dried at 70°C and 100 Pa for 1 hour. This yielded 1.69 g of a white solid.

[0131] The purity of the obtained solid was determined by high-performance liquid chromatography (HPLC) under the following conditions: column: ZORBAX RX-SiL (normal phase) manufactured by Agilent Technologies, Inc.; eluent: a 1:1 mass ratio of toluene and ethyl acetate; flow rate: 1.0 m / min; observation wavelength: 300 nm. The results (HPLC chromatograms) are shown below. Figure 8 By this Figure 8 It can be seen that the purity is approximately 99.6%. It should be noted that... Figure 8 The HPLC chromatogram of the fluorene compound involved in Example 2 is shown. The vertical axis represents intensity (mAU) and the horizontal axis represents elution time (minutes).

[0132] Furthermore, adopt 1 The obtained solid was analyzed by ¹H-NMR at 400 MHz with CD₂Cl₂ (containing 0.05% TMS by mass) as solvent. The results obtained from this analysis... 1 H-NMR spectrum (of the obtained solid) 1 The H-NMR spectrum is shown in Figure 9 According to the results obtained 1 The H-NMR spectrum shows that the solid is the fluorene compound represented by formula (4). Specifically, in the obtained 1 In the H-NMR spectrum, peak 91 near chemical shift δ7-8 represents the hydrogen of the aromatic ring in the fluorene compound represented by formula (4); peak 92 near chemical shift δ5-7 represents the hydrogen of the vinyl group in the fluorene compound represented by formula (4); and peaks 93 near chemical shift δ2 and near chemical shift δ0.5-1 represent the hydrogen of the propyl group in the fluorene compound represented by formula (4). Based on this, the solid is confirmed to be the fluorene compound represented by formula (4). It should be noted that peak 94 near chemical shift δ1.5 is a water-based peak, and peak 95 near chemical shift δ0 is a TMS-based peak. Figure 9 The fluorene compound involved in Example 2 is shown. 1 H-NMR spectrum, with the vertical axis representing intensity and the horizontal axis representing chemical shift δ.

[0133] Since the molecular weight of the fluorene compound shown in formula (4) is 455 and the purity is about 99.6%, the yield of the reaction is about 33%.

[0134] (Comparative Example 1)

[0135] The compound involved in Comparative Example 1 is the compound shown in the following formula (10) (4,4'-divinylbiphenyl (DVBP), DVBP manufactured by JFE Chemical Co., Ltd.).

[0136]

[0137] (Comparative Example 2)

[0138] The compound involved in Comparative Example 2 is the compound (fluorene) shown in the following formula (11).

[0139]

[0140] (Comparative Example 3)

[0141] The compound involved in Comparative Example 3 is the compound shown in Formula (12) below (9,9-di(4-allyloxyphenyl)fluorene).

[0142]

[0143] [evaluate]

[0144] The compounds involved in Examples 1, 2, and Comparative Examples 1-3 were evaluated as follows.

[0145] (Flame resistance)

[0146] The residual mass percentage (the ratio of the weight of the residue at 600°C to the mass before heating) of each compound involved in Examples 1, 2, and Comparative Examples 1-3 was determined using a thermogravimetric-differential thermal analysis (TG-DTA) apparatus (STA300 manufactured by Hitachi Advanced Technology & Science Co., Ltd.). It was found that the higher the residual mass percentage, the higher the flame retardancy; for example, if the residual mass percentage is 26% by mass or higher, sufficient flame retardancy is achieved.

[0147] (Dielectric properties: dielectric loss factor)

[0148] The dielectric loss factor of each compound involved in Examples 1, 2, and Comparative Examples 1-3 at 1 GHz was determined using the resonant cavity perturbation method. Specifically, the dielectric loss factor (Df) of each compound at 1 GHz was determined using a network analyzer (Keysight Technologies N5230A). If the dielectric loss factor Df obtained by measurement was between 0.00001 and 0.001, it was judged as "acceptable".

[0149] These results are shown in Table 1.

[0150]

[0151] As shown in Table 1, the residual mass percentage of the fluorene compound represented by Formula (1) (specifically, the fluorene compound involved in Example 1: the fluorene compound represented by Formula (3), and the fluorene compound involved in Example 2: the fluorene compound represented by Formula (4)) is higher than that of the compound involved in Comparative Example 2 (the compound represented by Formula (11)) and the compound involved in Comparative Example 3 (the compound represented by Formula (12)), specifically, by more than 30% by mass. In addition, the dielectric loss factor of the fluorene compound represented by Formula (1) is lower than that of the compound involved in Comparative Example 1 (the compound represented by Formula (10)) and the compound involved in Comparative Example 3 (the compound represented by Formula (12)), specifically, as low as 0.00001 to 0.001. Therefore, it can be seen that the fluorene compound represented by Formula (1) is a fluorene compound with low relative permittivity and dielectric loss factor and excellent flame retardancy.

[0152] When the fluorene compounds described in Examples 1 and 2 are included in the resin, compared with the case where the fluorene compounds described in Comparative Examples 1 to 3 are included in the resin in the same amount, regardless of the type of resin used to include the fluorene compounds, a resin composition with low relative permittivity and dielectric loss factor and excellent flame retardancy is obtained.

[0153] After curing, the prepreg obtained using the resin composition containing the fluorene compound described in Examples 1 and 2 has a lower relative permittivity and dielectric loss factor and better flame retardancy compared to the cured prepreg obtained using the fluorene compound described in Comparative Examples 1 to 3.

[0154] By curing a resin layer comprising a resin composition containing the fluorene compounds described in Examples 1 and 2, an insulating layer with a lower relative permittivity and dielectric loss factor and superior flame retardancy is obtained compared to an insulating layer obtained by curing a resin layer comprising the fluorene compounds described in Comparative Examples 1 to 3. Therefore, by using a resin composition containing the fluorene compounds described in Examples 1 and 2, it is possible to manufacture resin-coated metal foils and resin-coated films that, after curing, have a resin layer that is an insulating layer with a low relative permittivity and dielectric loss factor and superior flame retardancy. Furthermore, by using a resin composition containing the fluorene compounds described in Examples 1 and 2, metal foil laminates and wiring boards having an insulating layer with a low relative permittivity and dielectric loss factor and superior flame retardancy are obtained.

[0155] This application is based on Japanese Patent Application No. 2024-051827, filed on March 27, 2024, the contents of which are incorporated herein by reference.

[0156] To illustrate the invention, the present invention has been appropriately and sufficiently described above through embodiments. However, it should be recognized that those skilled in the art can readily make changes and / or modifications to the above embodiments. Therefore, any changes or modifications implemented by those skilled in the art that do not depart from the scope of protection of the claims set forth in the claims can be interpreted as being included within the scope of protection of the claims.

[0157] Industrial availability

[0158] According to the present invention, fluorene compounds with low relative permittivity and dielectric loss factor and excellent flame retardancy can be provided. Furthermore, according to the present invention, resin compositions containing the fluorene compounds, prepregs obtained using the resin compositions, resin-coated films, resin-coated metal foils, metal-coated laminates, and wiring boards can be provided.

Claims

1. A fluorene compound, characterized in that... The fluorene compound shown in formula (1) below, In formula (1), R1 and R2 each independently represent an alkyl group having 2 to 5 carbon atoms, and R3 and R4 each independently represent an alkenyl group and at least one of the groups shown in formula (2) below. In formula (2), p represents 0 to 10, R5 to R7 each independently represent a hydrogen atom or an alkyl group, and Ar represents an aryl group.

2. The fluorene compound according to claim 1, characterized in that, The fluorene compound represented by formula (1) comprises at least one of the fluorene compounds represented by formula (3) and formula (4). 。 3. The fluorene compound according to claim 1, characterized in that, The dielectric loss factor at 1 GHz is 0.00001 to 0.

001.

4. The fluorene compound according to claim 1, characterized in that, In thermogravimetric analysis, the weight after heating to 600°C is more than 26% of the weight before heating.

5. A resin composition, characterized in that... contain: The fluorene compound according to any one of claims 1 to 4; and Thermosetting resins.

6. A prepreg, characterized in that... include: The resin composition of claim 5 or a semi-cured product of the resin composition; as well as Fiber-based substrate.

7. A resin-coated membrane, characterized in that... include: A resin layer comprising the resin composition of claim 5 or a semi-cured product of the resin composition; as well as Support membrane.

8. A resin-coated metal foil, characterized in that... include: A resin layer comprising the resin composition of claim 5 or a semi-cured product of the resin composition; as well as Metal foil.

9. A metal foil-coated laminate, characterized in that... include: An insulating layer comprising the cured product of the resin composition of claim 5; as well as Metal foil.

10. A metal foil-coated laminate, characterized in that... include: An insulating layer comprising the cured prepreg of claim 6; as well as Metal foil.

11. A wiring board, characterized in that... include: An insulating layer comprising the cured product of the resin composition of claim 5; as well as wiring.

12. A wiring board, characterized in that... include: An insulating layer comprising the cured prepreg of claim 6; as well as wiring.

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