TW202440763A - Resin composition, prepreg, resin-coated film, resin-coated metal foil, metal-clad laminate and wiring board - Google Patents

Abstract

One aspect of the present invention relates to a resin composition comprising a free radical polymerizable compound (A) and an inorganic filler (B); the inorganic filler (B) comprises a boron nitride filler (b1); the boron nitride filler (b1) has a particle size distribution in which the cumulative value of 10% of the particle size (D10) is 0.5-2.0µm, the cumulative value of 50% of the particle size (D50) is 4.0-6.0µm, and the cumulative value of 90% of the particle size (D90) is 6.5-20.0µm.

Description

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

The present invention relates to a resin composition, a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate and a wiring board.

As the amount of information processing in various electronic devices increases, the mounting technology of the semiconductor devices they carry continues to develop, such as the high integration, high density and multi-layer wiring. In addition, the wiring boards used in various electronic devices are required to be capable of supporting high frequencies, such as millimeter wave radar substrates for vehicle-mounted use. In order to increase the transmission speed of signals, the wiring boards used in various electronic devices are required to reduce the loss during signal transmission, and this is particularly required for wiring boards that support high frequencies. In order to meet this demand, the substrate materials used to constitute the wiring boards used in various electronic devices are required to have low dielectric constants and dielectric tangents.

As the substrate material, for example, a PPE-containing resin composition is reported, which includes PPE (polyphenylene ether), a crosslinking curable compound, a phosphophenanthrene derivative, and silicon dioxide (Patent Document 1).

On the other hand, electronic materials used in PA (power amplification) substrates of base stations are required to have high thermal conductivity in addition to low dielectric constant and dielectric tangent. In this regard, the inorganic filler (silicon dioxide) contained in the resin composition of Patent Document 1 may not be able to obtain sufficient thermal conductivity.

In contrast, one of the methods for improving the thermal conductivity of resin compositions to date is to use boron nitride as an inorganic filler having high thermal conductivity (Patent Document 2).

We believe that by using the boron nitride filler and polyphenylene ether compound described in Patent Document 2, the low dielectric properties, thermal conductivity and heat resistance of the cured resin composition can be ensured. However, the resin composition described in Patent Document 2 may not have sufficient adhesion when used to make substrate products.

The present invention is made in view of the above circumstances, and its purpose is to provide a resin composition that can obtain a hardened material with low dielectric properties (low dielectric constant) and high thermal conductivity, and has excellent formability and adhesion when made into a substrate. In addition, the present invention aims to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate and a wiring board obtained using the above-mentioned resin composition. Prior art literature Patent literature

Patent document 1: Japanese Patent Publication No. 2015-67700 Patent document 2: International Publication No. 2021/059911

After various studies, the inventors of this case found that the above purpose can be achieved by the following structure, and further repeated studies led to the present invention.

That is, a resin composition of one embodiment of the present invention comprises a free radical polymerizable compound (A) and an inorganic filler (B), wherein the inorganic filler (B) comprises a boron nitride filler (b1); the particle size distribution of the boron nitride filler (b1) has a cumulative value of 10% particle size (D10) of 0.5-2.0µm, a cumulative value of 50% particle size (D50) of 4.0-6.0µm, and a cumulative value of 90% particle size (D90) of 6.5-20.0µm.

Forms for implementing the invention The following specifically describes the implementation forms of the present invention, but the present invention is not limited thereto.

[Resin composition] The resin composition of the embodiment of the present invention comprises a free radical polymerizable compound (A) and an inorganic filler (B). The inorganic filler (B) comprises a boron nitride filler (b1). Moreover, in the particle size distribution of the boron nitride filler (b1), the particle size (D10) of the cumulative value of 10% is 0.5~2.0µm, the particle size (D50) of the cumulative value of 50% is 4.0~6.0µm, and the particle size (D90) of the cumulative value of 90% is 6.5~20.0µm.

By the above-mentioned constitution, the following resin composition can be obtained: a resin composition that can obtain a cured product with low dielectric properties (especially relative dielectric constant: Dk) and high thermal conductivity, and excellent adhesion and formability when made into a substrate, etc. In addition, by using the above-mentioned resin composition, a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring substrate having the above-mentioned excellent properties can be provided.

The thermal conductivity of the cured product of the resin composition of this embodiment is preferably 1.0 W/mK or more, and the relative dielectric constant is preferably 4.0 or less. In addition, the relative dielectric constant is the relative dielectric constant at a frequency of 10 GHz.

First, the components of the resin composition of this embodiment are described.

(Free radical polymerizable compound (A)) The free radical polymerizable compound (A) of this embodiment is not particularly limited as long as it is a free radical polymerizable compound. More specifically, the free radical polymerizable compound (A) preferably includes at least one selected from the group consisting of a polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule, a hydrocarbon compound having a carbon-carbon unsaturated double bond in the molecule, a maleimide compound, and an allyl compound.

In addition, the radical polymerizable compound (A) preferably includes a radical polymerizable compound (A1) such as a compound having a reactive unsaturated group or a compound having a maleimide group, and in addition to the radical polymerizable compound (A1), it further preferably includes a radical polymerizable compound other than the radical polymerizable compound (A1) (other radical polymerizable compound) (A2). Each of them will be described below.

(Free radical polymerizable compound (A1)) First, the free radical polymerizable compound (A1) is described. The free radical polymerizable compound (A1) used in this embodiment is not particularly limited as long as it is a compound having free radical polymerizability. Examples thereof include compounds having reactive unsaturated groups such as carbon-carbon unsaturated double bonds, compounds having maleimide groups, and the like. By using the free radical polymerizable compound (A1), a resin composition having low dielectric properties in a cured product can be obtained.

The molecular weight of the radical polymerizable compound (A1) is preferably about 100 to 3000 in terms of weight average molecular weight. The weight average molecular weight may be any value measured by a general molecular weight measurement method, and specifically, a value measured by gel permeation chromatography (GPC) may be cited.

More specifically, the radical polymerizable compound (A1) preferably includes at least one selected from the group consisting of a polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule, a hydrocarbon compound having a carbon-carbon unsaturated double bond in the molecule, and a maleimide compound. Each of these will be described in more detail below.

・Polyphenylene ether compounds Polyphenylene ether compounds having carbon-carbon unsaturated double bonds in the molecule include, for example, polyphenylene ether compounds having groups represented by the following formula (1) or formula (2). We believe that by containing the modified polyphenylene ether compound, a resin composition can be obtained that can obtain a cured product having low dielectric properties and high heat resistance.

[Chemical formula 1]

In formula (1), s represents an integer of 0 to 10. Also, Z represents an aryl group. Also, R ₁ to R ₃ are each independent. That is, R ₁ to R ₃ may be the same group or different groups. Also, R ₁ to R ₃ represent a hydrogen atom or an alkyl group.

In formula (1), when s is 0, it means that Z is directly bonded to the terminal of the polyphenylene ether.

The arylene group of the above-mentioned Z is not particularly limited. The arylene group may be, for example, a monocyclic aromatic group such as a phenylene group, or a polycyclic aromatic group such as a naphthyl ring, etc. where the aromatic ring is not monocyclic. In addition, the arylene group also includes derivatives in which the hydrogen atom bonded to the aromatic ring has been substituted by a functional group such as an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group or an alkynylcarbonyl group. In addition, the above-mentioned alkyl group is not particularly limited, for example, it is preferably an alkyl group with 1 to 18 carbon atoms, and more preferably an alkyl group with 1 to 10 carbon atoms. Specifically, it may be, for example, a methyl group, an ethyl group, a propyl group, a hexyl group and a decyl group.

[Chemical formula 2]

In formula (2), _R4 represents a hydrogen atom or an alkyl group. The alkyl group is not particularly limited, and is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specifically, it includes methyl, ethyl, propyl, hexyl, and decyl groups.

Preferred specific examples of the substituent represented by the above formula (1) include substituents containing a vinylbenzyl group, etc. Examples of the above substituent containing a vinylbenzyl group include substituents represented by the following formula (3), etc. Examples of the substituent represented by the above formula (2) include acrylate groups and methacrylate groups, etc.

[Chemical formula 3]

More specifically, the substituents include vinyl benzyl/ethenyl benzyl such as p-vinyl benzyl and m-vinyl benzyl, vinyl phenyl, acrylate and methacrylate.

In the resin composition of this embodiment, the polyphenylene ether compound preferably has a group represented by the above formula (2). This is because it has the following advantages: the reactivity with the crosslinking agent can be improved, and a resin cured product with high heat resistance can be easily obtained.

The polyphenylene ether compound has a polyphenylene ether chain in the molecule, and preferably has a repeating unit represented by the following formula (4) in the molecule.

[Chemical formula 4]

In formula (4), t represents 1 to 50. Moreover, R ₅ to R ₈ are independent of each other. That is, R ₅ to R ₈ may be the same group or different groups. Moreover, R ₅ to R ₈ represent hydrogen atom, alkyl group, alkenyl group, alkynyl group, formyl group, alkylcarbonyl group, alkenylcarbonyl group or alkynylcarbonyl group. Among them, hydrogen atom and alkyl group are preferred.

Specifically, the functional groups listed in R ₅ to R ₈ include the following.

The alkyl group is not particularly limited, and is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specifically, it includes methyl, ethyl, propyl, hexyl, and decyl groups.

The alkenyl group is not particularly limited, and is preferably an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples include vinyl, allyl, and 3-butenyl.

The alkynyl group is not particularly limited, and is preferably an alkynyl group having 2 to 18 carbon atoms, and more preferably an alkynyl group having 2 to 10 carbon atoms. Specifically, examples thereof include ethynyl and prop-2-yn-1-yl (propargyl).

The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, and is preferably an alkylcarbonyl group having 2 to 18 carbon atoms, and more preferably an alkylcarbonyl group having 2 to 10 carbon atoms. Specifically, it includes acetyl, propionyl, butyryl, isobutyryl, trimethylacetyl, hexyl, octyl and cyclohexylcarbonyl groups.

The alkenylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkenyl group, and is preferably an alkenylcarbonyl group having 3 to 18 carbon atoms, and more preferably an alkenylcarbonyl group having 3 to 10 carbon atoms. Specific examples include acryloyl, methacryloyl, and crotonyl groups.

The alkynylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkynyl group, and for example, an alkynylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkynylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specifically, for example, a propynyl group is mentioned.

In the aforementioned polyphenylene ether compound, the average number of the aforementioned substituents (terminal functional groups) at the molecular end of each molecule of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.5 to 3. If the number of terminal functional groups is too small, it tends to be difficult to obtain a product that is sufficient in terms of heat resistance of the cured product. On the other hand, if the number of terminal functional groups is too large, the reactivity will become too high, and there is a risk that undesirable conditions such as reduced storage stability of the resin composition or reduced fluidity of the resin composition may occur. That is, if the aforementioned polyphenylene ether compound is used, there is a risk that due to insufficient fluidity, poor forming such as the generation of voids during multi-layer forming may occur, and it may be difficult to obtain a printed wiring board with high reliability.

In addition, the number of terminal functional groups of the polyphenylene ether compound can be represented by the value of the average value of the aforementioned substituents per molecule of all modified polyphenylene ether compounds present in 1 mol of the polyphenylene ether compound. The number of terminal functional groups can be measured, for example, by measuring the number of residual hydroxyl groups in the obtained modified polyphenylene ether compound and calculating the amount of reduction from the number of hydroxyl groups of the polyphenylene ether before modification. The amount of reduction from the number of hydroxyl groups of the polyphenylene ether before modification is the number of terminal functional groups. In addition, the method for measuring the number of residual hydroxyl groups in the modified polyphenylene ether compound can be obtained by adding a quaternary ammonium salt (tetraethylammonium hydroxide) that can allylate with hydroxyl groups to a solution of the modified polyphenylene ether compound and measuring the UV absorbance of the mixed solution.

The polyphenylene ether compound of the present embodiment may be, for example, a modified polyphenylene ether compound represented by the following formula (5) and a modified polyphenylene ether compound represented by the following formula (6). The polyphenylene ether compound of the present embodiment may be used alone or in combination of two modified polyphenylene ether compounds.

[Chemical formula 5]

[Chemical formula 6]

In formula (5) and formula (6), R ₉ to R ₁₆ and R ₁₇ to R ₂₄ each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a methyl group, an alkylcarbonyl group, an alkenylcarbonyl group or an alkynylcarbonyl group. X ₁ and X ₂ each independently represent a substituent having a carbon-carbon unsaturated double bond. A and B each represent a repeating unit represented by the following formula (7) and the following formula (8), respectively. In formula (6), Y represents a linear, branched or cyclic hydrocarbon having 20 or less carbon atoms.

[Chemical formula 7]

[Chemical formula 8]

In formula (7) and formula (8), m and n each represent 0 to 20. R ₂₅ to R ₂₈ and R ₂₉ to R ₃₂ each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group or an alkynylcarbonyl group.

The modified polyphenylene ether compound represented by the aforementioned formula (5) and the modified polyphenylene ether compound represented by the aforementioned formula (6) are not particularly limited as long as they are compounds satisfying the above-mentioned composition. Specifically, in the aforementioned formula (5) and the aforementioned formula (6), R ₉ to R ₁₆ and R ₁₇ to R ₂₄ are independent of each other as described above. That is, R ₉ to R ₁₆ and R _{17 to R 24 may be the same group or different groups. In addition, R 9 to R 16 and R 17 to R 24 represent a hydrogen atom} , an alkyl group, an alkenyl group, an alkynyl group, a methyl group, an alkylcarbonyl group, an alkenylcarbonyl group or an alkynylcarbonyl group. Among them, hydrogen atoms and alkyl groups are preferred.

In formula (7) and formula (8), m and n are preferably 0 to 20 as described above. Moreover, m and n are preferably a value in which the sum of m and n is 1 to 30. Therefore, it is preferred that m represents 0 to 20, n represents 0 to 20, and the sum of m and n represents 1 to 30. Moreover, R ₂₅ to R ₂₈ and R ₂₉ to R 32 are independent of each other. That is, R ₂₅ to R ₂₈ and R ₂₉ to R ₃₂ may be the same group or different groups. Moreover, R ₂₅ to R ₂₈ and R ₂₉ to R ₃₂ represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a methyl group, an alkylcarbonyl group, an alkenylcarbonyl group or an alkynylcarbonyl group. Among them, hydrogen _atom and alkyl group are preferred.

R ₉ to R ₃₂ are the same as R ₅ to R ₈ in the above formula (4).

In the above formula (6), Y is as described above, and is a linear, branched or cyclic hydrocarbon having a carbon number of not more than 20. Examples of Y include a group represented by the following formula (9).

[Chemical formula 9]

In the above formula (9), R ₃₃ and R ₃₄ each independently represent a hydrogen atom or an alkyl group. Examples of the above alkyl group include methyl group. Examples of the group represented by formula (9) include methylene group, methylmethylene group, and dimethylmethylene group, among which dimethylmethylene group is preferred.

In the aforementioned formula (5) and the aforementioned formula (6), _X1 and _X2 are each independently a substituent having a carbon-carbon unsaturated double bond. The substituents _X1 and _X2 are not particularly limited as long as they are substituents having a carbon-carbon unsaturated double bond. The aforementioned substituents _X1 and _X2 can be, for example, the substituents represented by the aforementioned formula (1) and the substituents represented by the aforementioned formula (2). In addition, in the modified polyphenylene ether compound represented by the aforementioned formula (5) and the modified polyphenylene ether compound represented by the aforementioned formula (6), _X1 and _X2 may be the same substituent or different substituents.

More specific examples of the modified polyphenylene ether compound represented by the above formula (5) include the modified polyphenylene ether compound represented by the following formula (10).

[Chemical formula 10]

More specific examples of the modified polyphenylene ether compound represented by the above formula (6) include the modified polyphenylene ether compound represented by the following formula (11) and the modified polyphenylene ether compound represented by the following formula (12).

[Chemical formula 11]

[Chemical formula 12]

In the above formula (10) and formula (11), m and n are the same as m and n in the above formula (7) and formula (8). In the above formula (10) and formula (11), R ₁ to R ₃ , p and Z are the same as R ₁ to R ₃ , s and Z in the above formula (1), respectively. In the above formula (11) and formula (12), Y is the same as Y in the above formula (9). In the above formula (12), R ₄ is the same as R ₄ in the above formula (2).

We believe that by using the modified polyphenylene ether compound as described above, low dielectric properties such as low dielectric constant and excellent heat resistance can be maintained, and high Tg and adhesion can also be improved.

The modified polyphenylene ether compound may be used alone or in combination of two or more.

The polyphenylene ether compound used in the resin composition of the present embodiment can be synthesized by a known method, or a commercially available product can be used. Examples of commercially available products include "OPE-2st 1200" and "OPE-2st 2200" manufactured by Mitsubishi Gas Chemical Co., Ltd. and "SA9000" manufactured by SABIC Innovative Plastics Co., Ltd.

・Hydrocarbon compounds having carbon-carbon unsaturated double bonds in the molecule The hydrocarbon resins that can be used in this embodiment are not particularly limited as long as they are hydrocarbon resins having unsaturated double bonds, and preferred examples include hydrocarbon resins such as polyfunctional vinyl aromatic polymers, cyclic polyolefin hydrocarbon resins, and vinyl aromatic compound-covalent diene compound copolymers.

The polyfunctional vinyl aromatic polymer is preferably a polymer obtained by polymerization of at least a polyfunctional vinyl aromatic compound and/or its derivatives. There is no particular limitation as long as it is a polymer containing a structure derived from a polyfunctional vinyl aromatic compound and/or its derivatives. It may also be a polymer containing a structure derived from one or more polyfunctional vinyl aromatic compounds and/or their derivatives.

In addition to the structural units of the polyfunctional vinyl aromatic compound and/or its derivatives, one or more structural units derived from reactive monomers may be included. The reactive monomer is not particularly limited and may be, for example, a polyfunctional vinyl aromatic copolymer having structural units derived from monovinyl aromatic compounds such as styrene.

More specifically, it includes polyfunctional vinyl compounds having two or more vinyl groups in the molecule. In addition, the polyfunctional vinyl compounds include divinylbenzene, divinylnaphthalene, divinylbiphenyl and polybutadiene.

・Maleimide compound The maleimide resin that can be used in this embodiment can be used without particular limitation as long as it is a compound having a maleimide group in the molecule. Specifically, the maleimide compound mentioned above can include a monofunctional maleimide compound having one maleimide group in the molecule, a polyfunctional maleimide compound having two or more maleimide groups in the molecule, and a modified maleimide compound. The modified maleimide compound mentioned above can include, for example, a modified maleimide compound in which a part of the molecule has been modified with an amine compound, a modified maleimide compound in which a part of the molecule has been modified with a polysiloxane compound, and a modified maleimide compound in which a part of the molecule has been modified with an amine compound and a polysiloxane compound.

More specifically, examples include maleimide compounds having two or more N-substituted maleimide groups in one molecule, maleimide compounds having an indane structure, maleimide compounds having at least one selected from an alkyl group having 6 or more carbon atoms and an alkylene group having 6 or more carbon atoms, and maleimide compounds having a benzene ring in the molecule.

The maleimide compound used in the present embodiment may be a commercially available product, for example, BMI-4000, BMI-2300, BMI-TMH, BMI-4000, BMI-5100, etc. manufactured by Yamato Kasei Industries, Ltd.; MIR-3000, MIR-5000 manufactured by Nippon Kayaku Co., Ltd.; BMI-689, BMI-1500, BMI-3000J, BMI-5000, etc. manufactured by Designer Molecules Inc.

(Other radical polymerizable compounds (A2)) The resin composition of this embodiment may also contain other radical polymerizable compounds (A2) other than the radical polymerizable compounds (polyphenylene ether compounds, hydrocarbon compounds, maleimide compounds) described above. The radical polymerizable compound (A2) is preferably a radical polymerizable compound that can function as a curing agent that reacts with the radical polymerizable compound (A1) (polyphenylene ether compounds, hydrocarbon compounds, maleimide compounds, etc.) described above.

Examples of the radical polymerizable compound (A2) include allyl compounds, vinyl compounds, methacrylate compounds, acrylate compounds, and acenaphthene compounds.

The allyl compound is a compound having an allyl group in the molecule, and examples thereof include triallyl isocyanurate compounds such as triallyl isocyanurate (TAIC), diallylbisphenol compounds, and diallyl phthalate (DAP).

The aforementioned vinyl compound is a compound having a vinyl group in the molecule. Examples of the aforementioned vinyl compound include a monofunctional vinyl compound (monovinyl compound) having one vinyl group in the molecule, and a polyfunctional vinyl compound having two or more vinyl groups in the molecule. Examples of the aforementioned monofunctional vinyl compound include styrene compounds, etc. Examples of the aforementioned polyfunctional vinyl compound include polyfunctional aromatic vinyl compounds and vinyl hydrocarbon compounds, etc. Examples of the aforementioned polyfunctional aromatic vinyl compound include divinylbenzene, etc. Examples of the aforementioned vinyl hydrocarbon compounds include polybutadiene compounds, etc.

The aforementioned methacrylate compound is a compound having a methacrylic group in the molecule, and examples thereof include a monofunctional methacrylate compound having one methacrylic group in the molecule, and a polyfunctional methacrylate compound having two or more methacrylic groups in the molecule. Examples of the aforementioned monofunctional methacrylate compound include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Examples of the aforementioned polyfunctional methacrylate compound include dimethacrylate compounds such as tricyclodecanedimethanol dimethacrylate (DCP), and the like.

The aforementioned acrylate compound is a compound having an acryl group in the molecule, and examples thereof include a monofunctional acrylate compound having one acryl group in the molecule and a multifunctional acrylate compound having two or more acryl groups in the molecule. Examples of the aforementioned monofunctional acrylate compound include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. Examples of the aforementioned multifunctional acrylate compound include diacrylate compounds such as tricyclodecanedimethanol diacrylate.

The aforementioned acenaphthene compound is a compound having an acenaphthene structure in the molecule. Examples of the aforementioned acenaphthene compound include acenaphthene, alkyl acenaphthenes, halogenated acenaphthenes, and phenyl acenaphthenes. Examples of the aforementioned alkyl acenaphthenes include 1-methyl acenaphthene, 3-methyl acenaphthene, 4-methyl acenaphthene, 5-methyl acenaphthene, 1-ethyl acenaphthene, 3-ethyl acenaphthene, 4-ethyl acenaphthene, and 5-ethyl acenaphthene. Examples of the aforementioned halogenated acenaphthenes include 1-chloro acenaphthene, 3-chloro acenaphthene, 4-chloro acenaphthene, 5-chloro acenaphthene, 1-bromo acenaphthene, 3-bromo acenaphthene, 4-bromo acenaphthene, and 5-bromo acenaphthene. Examples of the aforementioned phenyl acenaphthenes include 1-phenyl acenaphthene, 3-phenyl acenaphthene, 4-phenyl acenaphthene, and 5-phenyl acenaphthene. The acenaphthene compound may be a monofunctional acenaphthene compound having one acenaphthene structure in the molecule as described above, or may be a polyfunctional acenaphthene compound having two or more acenaphthene structures in the molecule.

In this embodiment, as the other radical polymerizable compound (A2), among the above-mentioned radical polymerizable compounds, it is preferable to use allyl compounds, polyfunctional aromatic vinyl compounds, polyfunctional methacrylate compounds, polyfunctional acrylate compounds, polybutadiene compounds, acenaphthene compounds and styrene compounds.

The radical polymerizable compound (A) may be composed of the polyphenylene ether compound (A1), or may be composed of the aforementioned radical polymerizable compound (other radical polymerizable compound) (A2) other than the polyphenylene ether compound (A1). In a preferred embodiment, the radical polymerizable compound (A) preferably includes the radical polymerizable compound (A1) as described above, and more preferably includes the polyphenylene ether compound (A1) and the other radical polymerizable compound (A2). The other radical polymerizable compound (A2) may be used alone or in combination of two or more.

The content of the free radical polymerizable compound (A) in the resin composition of this embodiment is preferably about 50-100 mass %, and more preferably about 60-80 mass %, relative to the resin component (organic resin component in the resin composition) as a whole. We believe that this can more reliably obtain low dielectric properties in the cured product.

When the radical polymerizable compound (A) includes the radical polymerizable compound (A1), the content thereof is preferably 30 to 100 parts by mass, more preferably 50 to 90 parts by mass, relative to 100 parts by mass of the radical polymerizable compound (A). When the content of the radical polymerizable compound (A1) is within the above range, the resin composition can be suitably cured, and in the cured product, excellent low dielectric properties, interlayer adhesion and flame retardancy can be maintained, and the glass transition temperature can be sufficiently increased.

(Other thermosetting resins and hardeners) The resin composition of this embodiment may contain other thermosetting resins in addition to the free radical polymerizable compound (A) as described above.

Examples of thermosetting resins that can be used in this embodiment include epoxy compounds, cyanate compounds, phenol compounds, benzophenone compounds, active ester compounds, etc. Among these, benzophenone compounds, etc. are preferably used from the viewpoint of curability and moldability.

When the resin composition of this embodiment further comprises the aforementioned thermosetting resin in addition to the free radical polymerizable compound (A), the ratio of the free radical polymerizable compound (A) to the thermosetting resin is preferably about 95:5 to 50:50 in terms of mass ratio.

(Inorganic filler) ・Boron nitride filler (b1) The resin composition of this embodiment includes an inorganic filler (B). Furthermore, the inorganic filler (B) includes a boron nitride filler (b1) having a predetermined particle size distribution. Specifically, the particle size distribution of the boron nitride filler (b1) has a cumulative value of 10% particle size (D10) of 0.5 to 2.0 µm, a cumulative value of 50% particle size (D50) of 4.0 to 6.0 µm, and a cumulative value of 90% particle size (D90) of 6.5 to 20.0 µm.

The resin composition of this embodiment uses the boron nitride filler (b1) having the above-mentioned particle size distribution as the boron nitride filler with high thermal conductivity, and thus becomes a resin composition foreign body with good thermal conductivity, and good results can be obtained in terms of moldability and adhesion when the substrate is made. If the particle size distribution of the boron nitride filler (b1) exceeds the above-mentioned range, there is a tendency that the thermal conductivity is reduced or the moldability and adhesion are reduced.

In this specification, the particle size distribution is a value obtained by particle size distribution measurement using a laser diffraction scattering method, and can be measured, for example, by a laser/diffraction particle size distribution measuring apparatus "LA-960V2" (manufactured by Horiba, Ltd.) used in the embodiments described below.

The boron nitride filler (b1) that can be used in this embodiment is not particularly limited as long as it can be used as an inorganic filler contained in the resin composition and satisfies the above-mentioned particle size distribution requirements. Examples of boron nitride include hexagonal normal pressure phase (h-BN) and cubic high pressure phase (c-BN).

The average aspect ratio of the boron nitride filler (b1) is preferably 6 to 20. The average aspect ratio in this specification refers to the value obtained by dividing the maximum length in the main surface of the boron nitride filler particle by the thickness in the direction perpendicular to the main surface. The aforementioned maximum length and the aforementioned thickness can be measured by observing the boron nitride filler (b1) with a scanning electron microscope (SEM), and the average aspect ratio can be calculated from the measured values. By setting the aforementioned average aspect ratio to 6 to 20, a resin composition that becomes a cured product with high thermal conductivity can be obtained.

The content of the boron nitride filler (b1) is preferably 5 to 50 parts by volume relative to 100 parts by volume of the free radical polymerizable compound (A). We believe that by setting the content to the above, the effect exerted by the boron nitride filler (b1) as described above can be more reliably obtained. The above content is preferably in the range of 8 to 30 parts by volume, and more preferably in the range of 10 to 25 parts by volume.

・Silica filler (b2) The resin composition of this embodiment preferably further includes a silica filler (b2) as an inorganic filler in addition to the boron nitride filler (b1). By including the silica filler (b2), there are advantages of reducing costs, ensuring sealing properties, and improving thermal conductivity due to the high filling of the inorganic filler.

The silica filler (b2) used in this embodiment is not particularly limited as long as it can be used as an inorganic filler for the resin composition. The silica filler in this embodiment may be a silica filler that has been surface treated or may be a silica filler that has not been surface treated. The surface treatment may be, for example, treatment with a silane coupling agent.

The aforementioned silane coupling agent may be, for example, a silane coupling agent having at least one functional group selected from the group consisting of a vinyl group, a styryl group, a methacryl group, an acryl group, and an anilino group. That is, the silane coupling agent may be a compound having at least one of a vinyl group, a styryl group, a methacryl group, an acryl group, and an anilino group as a reactive functional group and further having a hydrolyzable group such as a methoxy group or an ethoxy group.

Examples of the silane coupling agent having a vinyl group include vinyl triethoxysilane and vinyl trimethoxysilane. Examples of the silane coupling agent having a styryl group include p-styryl trimethoxysilane and p-styryl triethoxysilane. Examples of the silane coupling agent having a methacryl group include 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyl dimethoxysilane, 3-methacryloxypropyl triethoxysilane, 3-methacryloxypropyl methyl diethoxysilane, and 3-methacryloxypropyl ethyl diethoxysilane. Examples of the silane coupling agent having an acryl group include 3-acryloxypropyltrimethoxysilane and 3-acryloxypropyltriethoxysilane. Examples of the silane coupling agent having an anilino group include N-phenyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltriethoxysilane.

The content of the silica filler (b2) is not particularly limited, but is preferably contained in such a manner that the volume content ratio of the boron nitride filler (b1) to the silica filler (b2) in the inorganic filler (B), that is, the volume content of the boron nitride filler (b1)/the volume content of the silica filler (b2) is 1 to 4. This has the advantage of being able to obtain excellent adhesion and moldability while maintaining thermal conductivity.

Furthermore, the content of the silica filler (b2) is preferably 20 to 60 parts by volume, more preferably 30 to 50 parts by volume, relative to 100 parts by volume of the radical polymerizable compound (A).

The inorganic filler (B) may further include inorganic fillers other than the boron nitride filler (b1) and the silicon dioxide filler (b2). The inorganic fillers other than the aforementioned boron nitride and silicon dioxide are not particularly limited as long as they can be used as inorganic fillers contained in the resin composition. Specifically, metal oxides such as aluminum oxide fillers, titanium oxide fillers, magnesium oxide fillers and mica fillers, metal hydroxides such as aluminum hydroxide fillers and magnesium hydroxide fillers, talc fillers, aluminum borate fillers, barium sulfate fillers, aluminum nitride fillers, silicon nitride fillers, anhydrous magnesium carbonate fillers, magnesium carbonate fillers and calcium carbonate fillers can be cited. Among them, anhydrous magnesium carbonate fillers, aluminum oxide fillers and silicon nitride fillers are preferred.

The inorganic fillers other than the boron nitride filler and the silicon dioxide filler may be inorganic fillers that have been surface treated or inorganic fillers that have not been surface treated. In addition, the surface treatment may be, for example, treatment with a silane coupling agent.

Furthermore, the total content of the inorganic filler (B) in the resin composition of this embodiment is preferably 5 to 70 parts by volume, more preferably 30 to 60 parts by volume, relative to 100 parts by volume of the radical polymerizable compound (A).

(Phosphorus compound (C)) The resin composition of this embodiment preferably further contains a phosphorus compound (C). This can further improve the flame retardancy.

The phosphorus compound (C) of this embodiment is not particularly limited as long as it has flame retardancy, and preferably contains a compatible phosphorus compound (c1) that is compatible with the free radical polymerizable compound (A) and an incompatible phosphorus compound (c2) that is incompatible with the free radical polymerizable compound (A). We believe that this has the advantage of further improving flame retardancy and becoming a resin composition with high heat resistance and adhesion.

The compatible phosphorus compound (c1) is not particularly limited as long as it functions as a flame retardant and is compatible with the radical polymerizable compound (A). Here, compatible means being finely dispersed in the radical polymerizable compound (A) at a molecular level, for example.

Specific examples of the compatible phosphorus compound (c1) include phosphorus-containing compounds that do not form salts, such as phosphate compounds, phosphazene compounds, phosphite compounds, and phosphine compounds.

Examples of the phosphazene compound include cyclic or chain phosphazene compounds. In addition, cyclic phosphazene compounds are also called cyclophosphazenes, which are compounds having a double bond with phosphorus and nitrogen as constituent elements in the molecule and have a cyclic structure. Examples of the phosphate ester compound include triphenyl phosphate, tricresyl phosphate, ditolyl diphenyl phosphate, tolylene diphenyl phosphate, 1,3-phenylenebis(di-2,6-diphosphoditolylene), 9,10-dihydro-9-oxo-10-phosphaphenanthrene-10-oxide (DOPO), aromatic condensed phosphate compounds, and cyclic phosphate compounds. Examples of the phosphite compound include trimethyl phosphite and triethyl phosphite. Examples of the phosphine compound include tris-(4-methoxyphenyl)phosphine and triphenylphosphine. The above-mentioned compatible phosphorus compounds may be used alone or in combination of two or more.

The incompatible phosphorus compound (c2) is not particularly limited as long as it functions as a flame retardant and is incompatible with the radical polymerizable compound (A). Here, incompatible means that it is incompatible with the radical polymerizable compound (A) and the target object (phosphorus compound) is dispersed in the mixture in the form of islands.

Specific examples of the incompatible phosphorus compound (c2) include phosphorus-containing compounds that form salts, such as isophosphite compounds, polyphosphate compounds, and phosphonium salt compounds, and phosphine oxide compounds.

Examples of the isophosphite compound include dialkyl aluminum isophosphite, tris(diethyl) aluminum isophosphite, tris(methyl) ethyl aluminum isophosphite, tris(diphenyl) aluminum isophosphite, bis(diethyl) zinc isophosphite, bis(methyl) ethyl zinc isophosphite, bis(diphenyl) zinc isophosphite, bis(diethyl) titanium isophosphite, bis(methyl) ethyl titanium isophosphite, bis(diphenyl) titanium isophosphite, etc. Examples of the polyphosphate compound include melamine polyphosphate, melam polyphosphate, melem polyphosphate, etc. Examples of the phosphonium salt compound include tetraphenylphosphonium tetraphenylborate and tetraphenylphosphonium bromide, etc. The phosphine oxide compound includes, for example, a phosphine oxide compound having two or more diphenylphosphine oxide groups in the molecule (diphenylphosphine oxide compound), and more specifically, a para-stubyl bis(diphenylphosphine oxide), etc. The aforementioned incompatible phosphorus compounds may be used alone or in combination of two or more.

The content ratio of the compatible phosphorus compound (c1) to the incompatible phosphorus compound (c2) is preferably 1:1 to 1:3, more preferably 1:2 to 2:3, in terms of mass ratio. We believe that as long as the content ratio is the above, the cured product will have a high Tg and become a resin composition with better flame retardancy.

The resin composition of the present embodiment may contain only the phosphorus compound (C) as a flame retardant, or may contain flame retardants other than the phosphorus compound (C). However, from the viewpoint of being halogen-free, it is preferred not to contain a halogen-based flame retardant.

When the resin composition of this embodiment contains the phosphorus compound (C), the content thereof is preferably about 5 to 80 parts by mass, more preferably about 10 to 60 parts by mass, based on 100 parts by mass of the radical polymerizable compound (A).

(Reaction initiator) The resin composition of this embodiment may further include a reaction initiator. Even without a reaction initiator, the free radical polymerization (curing) reaction can still proceed in the aforementioned resin composition. However, depending on the process conditions, it may be difficult to maintain a high temperature until the curing proceeds, so a reaction initiator may also be added.

The reaction initiator is not particularly limited as long as it can promote the curing reaction of the resin composition. Specifically, it can be metal oxides, azo compounds, peroxides, etc., preferably at least one of peroxides and azo compounds.

Specific examples of the metal oxide include carboxylic acid metal salts and the like.

Examples of organic peroxides include α, α'-di(tertiary butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(tertiary butylperoxy)-3-hexyne, benzoyl peroxide, 3,3',5,5'-tetramethyl-1,4-diphenoquinone, chloranil, 2,4,6-tri-tertiary butylphenoxy, tertiary butylperoxyisopropyl monocarbonate, azobisisobutyronitrile, and the like.

Specific examples of the azo compound include 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(N-butyl-2-methylpropionamide), and 2,2'-azobis(2-methylbutyronitrile).

Among them, the ideal reaction initiator is 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(N-butyl-2-methylpropionamide), etc. These reaction initiators have little effect on the dielectric properties. In addition, this is because they have the following advantages: since the reaction initiation temperature is relatively high, the promotion of the curing reaction at the time point when the prepreg is dried and no curing is required can be suppressed, thereby suppressing the reduction of the storage property of the above-mentioned resin composition.

The reaction initiators mentioned above may be used alone or in combination of two or more.

When the resin composition of the present embodiment contains the reaction initiator, its content is not particularly limited. For example, it is preferably 0.1 to 5.0 parts by mass, more preferably 0.5 to 3.0 parts by mass, and even more preferably 0.5 to 2.0 parts by mass, relative to 100 parts by mass of the radical polymerizable compound (A).

(Other elastomers) In addition, in the resin composition of this embodiment, in order to more reliably ensure low dielectric properties or bonding strength, in addition to the above-mentioned free radical polymerizable compound (A), a thermoplastic resin without unsaturated groups may be added.

Examples of the thermoplastic resin include thermoplastic polyphenylene ether resin, polyphenylene sulfide resin, liquid crystal polymer, polyethylene resin, polystyrene resin, polyurethane resin, polypropylene resin, ABS resin, acrylic resin, polyethylene terephthalate resin, polycarbonate resin, polyacetal resin, polyimide resin, polyamide imide resin, polytetrafluoroethylene resin, cycloolefin polymer, cycloolefin copolymer, styrene elastomer, etc. The above resins may be used alone or in combination of two or more.

When the resin composition of this embodiment includes a thermoplastic resin having no unsaturated group, its content is preferably about 0.1 to 30 parts by mass, more preferably about 1 to 15 parts by mass, relative to 100 parts by mass of the total of the free radical polymerizable compound (A) component and the aforementioned thermoplastic resin.

(Other ingredients) The resin composition of this embodiment may also contain ingredients (other ingredients) other than the above ingredients as required within the scope that does not impair the effect of the present invention. The other ingredients contained in the resin composition of this embodiment may further include additives such as silane coupling agents, defoaming agents, antioxidants, thermal stabilizers, antistatic agents, ultraviolet absorbers, dyes or pigments, dispersants and lubricants.

(Manufacturing method) The method for manufacturing the aforementioned resin composition is not particularly limited, and for example, a method of mixing the aforementioned free radical polymerizable compound (A) with other resin components as required and then adding an inorganic filler can be used. Specifically, when obtaining a varnish-like composition containing an organic solvent, the method described in the description of the prepreg described later can be used.

Furthermore, by using the resin composition of the present embodiment, a prepreg, a metal-clad laminate, a wiring board, a metal foil with resin, and a film with resin can be obtained as described below. In the following description, each symbol represents the following meaning: 1: prepreg, 2: resin composition or semi-cured product of resin composition, 3: fiber substrate, 11: metal-clad laminate, 12: insulating layer, 13: metal foil, 14: wiring, 21: wiring board, 31: metal foil with resin, 32, 42: resin layer, 41: film with resin, 43: supporting film.

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

As shown in Fig. 1, the prepreg 1 of this embodiment comprises the resin composition or the semi-cured product 2 of the resin composition and a fiber substrate 3. The prepreg 1 comprises the resin composition or the semi-cured product 2 of the resin composition and the fiber substrate 3 present in the resin composition or the semi-cured product 2 of the resin composition.

In addition, in the present embodiment, the semi-cured material refers to a state in which the resin composition is halfway cured to the extent that it can be further cured. That is, the semi-cured material is a resin composition in a semi-cured state (after B-stage). For example, when the resin composition is heated, the viscosity will slowly decrease at first, then it will start to harden, and then it will start to harden and the viscosity will slowly increase. At this time, the semi-cured state can be exemplified by the state from the beginning of the viscosity increase to the period before complete hardening.

Furthermore, the prepreg obtained using the resin composition of the present embodiment may be a semi-cured product of the resin composition as described above, or may be a product of the uncured resin composition itself. That is, it may be a prepreg having a semi-cured product of the resin composition (the resin composition described above in the B stage) and a fiber substrate, or may be a prepreg having the resin composition described above before curing (the resin composition described above in the A stage) and a fiber substrate. Furthermore, the resin composition or the semi-cured product of the resin composition may be a dried or heat-dried resin composition.

When manufacturing the prepreg, the resin composition 2 is often prepared into a varnish-like state for use in order to impregnate the fiber substrate 3 used to form the prepreg. That is, the resin composition 2 is usually often prepared into a varnish-like resin varnish. The varnish-like resin composition (resin varnish) can be prepared, for example, in the following manner.

First, each component of the resin composition that can be dissolved in an organic solvent is put into an organic solvent to dissolve it. At this time, heating can also be performed as required. Then, components that are insoluble in organic solvents (such as inorganic fillers, etc.) are added as required, and a ball mill, a bead mill, a planetary mixer, a roller mill, etc. are used to disperse until a predetermined dispersion state is reached, thereby preparing a varnish-like resin composition. The organic solvent used here is not particularly limited as long as it can dissolve the aforementioned free radical polymerizable compound and does not hinder the curing reaction. Specifically, toluene or methyl ethyl ketone (MEK) can be cited.

The method for producing the prepreg is not particularly limited as long as the prepreg can be produced. Specifically, when producing the prepreg, the resin composition used in the present embodiment is often prepared into a varnish state as described above and used as a resin varnish.

Specifically, the aforementioned fiber substrates include glass cloth, aramid cloth, polyester cloth, glass non-woven cloth, aramid non-woven cloth, polyester non-woven cloth, pulp paper, and lint paper. In addition, if glass cloth is used, a laminate with excellent mechanical strength can be obtained, and glass cloth that has been flattened is particularly suitable. For the flattening tool body, for example, a method of continuously pressing the glass cloth with a roller under appropriate pressure to compress the yarn into a flat state can be used. In addition, the thickness of the fiber substrate generally used is, for example, not less than 0.01 mm and not more than 0.3 mm.

The method for producing the prepreg is not particularly limited as long as the prepreg can be produced. Specifically, when producing the prepreg, the resin composition of the present embodiment is often prepared into a varnish state as described above and used as a resin varnish.

The method of manufacturing the prepreg 1 includes, for example, a method of impregnating the fiber substrate 3 with the resin composition 2, for example, the resin composition 2 prepared into a varnish state, and then drying. The resin composition 2 can be impregnated into the fiber substrate 3 by impregnation and coating. The impregnation can also be repeated several times as required. In addition, at this time, it is also possible to adjust the final desired composition and impregnation amount by repeatedly impregnating with multiple resin compositions of different compositions or concentrations.

The fiber substrate 3 impregnated with the resin composition (resin varnish) 2 can be heated under desired heating conditions, for example, 80°C to 180°C for 1 minute to 10 minutes. By heating, a prepreg 1 before curing (stage A) or in a semi-cured state (stage B) can be obtained. In addition, by the aforementioned heating, the organic solvent can be volatilized from the aforementioned resin varnish, thereby reducing or removing the organic solvent.

[Metal-clad laminate] Fig. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate 11 in an embodiment of the present invention.

As shown in FIG2 , the metal-clad laminate 11 is composed of an insulating layer 12 and a metal foil 13. The insulating layer 12 includes a cured product of the prepreg 1 shown in FIG1 , and the metal foil 13 is laminated on the insulating layer 12. That is, the metal-clad laminate 11 has an insulating layer 12 including a cured product of a resin composition and a metal foil 13 disposed on the insulating layer 12. The insulating layer 12 may be composed of a cured product of the resin composition or a cured product of the prepreg. The thickness of the metal foil 13 may vary depending on the performance required for 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, for example, preferably 0.2~70μm. In addition, the metal foil 13 can be, for example, copper foil and aluminum foil. When the metal foil is thinner, in order to improve the handling property, it can also be a copper foil with a peeling layer and a carrier.

The method for manufacturing the aforementioned metal-clad laminate 11 is not particularly limited as long as the aforementioned metal-clad laminate 11 can be manufactured. Specifically, a method for manufacturing the metal-clad laminate 11 using the prepreg 1 can be cited. The method can be exemplified by the following method, etc.: take one sheet of prepreg 1 or stack a plurality of sheets of prepreg 1, then stack a metal foil 13 such as copper foil on both sides or on one side thereof, and heat and press the metal foil 13 and the prepreg 1 to form a whole, thereby manufacturing the laminate 11 with metal foils on both sides or on one side. That is, the metal-clad laminate 11 is obtained by laminating the metal foil 13 on the prepreg 1 and then heating and pressurizing it. Furthermore, the heating and pressurizing conditions can be appropriately set according to the thickness of the metal-clad laminate 11 to be manufactured or the type of the composition of the prepreg 1. For example, the temperature can be set to 170-230°C, the pressure can be set to 3-5 MPa, and the time can be set to 60-150 minutes. Furthermore, the metal-clad laminate can also be manufactured without using a prepreg. For example, a method can be cited in which a varnish-like resin composition is applied to a metal foil, a layer containing the resin composition is formed on the metal foil, and then heating and pressurizing are performed.

[Wiring board] Fig. 3 is a schematic cross-sectional view showing an example of a wiring board 21 according to an embodiment of the present invention.

As shown in FIG3 , the wiring board 21 of the present embodiment is composed of an insulating layer 12 and wirings 14. The insulating layer 12 is used by hardening the prepreg 1 shown in FIG1 , and the wirings 14 are laminated on the insulating layer 12 and formed by partially removing the metal foil 13. That is, the wiring board 21 has the insulating layer 12 including a hardened product of a resin composition and the wirings 14 provided on the insulating layer 12. The insulating layer 12 may be composed of a hardened product of the resin composition or a hardened product of the prepreg.

The method for manufacturing the aforementioned wiring board 21 is not particularly limited as long as the aforementioned wiring board 21 can be manufactured. Specifically, a method for manufacturing the wiring board 21 using the aforementioned prepreg 1 can be cited. This method can be, for example, a method for manufacturing the wiring board 21 having wiring as a circuit on the surface of the insulating layer 12 by etching the metal foil 13 on the surface of the metal-clad laminate 11 manufactured in the above manner. That is, the wiring board 21 is obtained by partially removing the metal foil 13 on the surface of the metal-clad laminate 11 to form a circuit. In addition, in addition to the above-mentioned method, the method for forming the circuit can also be cited as forming the circuit using a semi-additive process (SAP: Semi Additive Process) or a modified semi-additive process (MSAP: Modified Semi Additive Process).

[Resin-coated metal foil] Fig. 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil 31 of the present embodiment.

As shown in FIG. 4 , the resin-coated metal foil 31 of the present embodiment includes a resin layer 32 including 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 on the resin layer 32. Furthermore, the resin-coated metal foil 31 may also include another layer between the resin layer 32 and the metal foil 13.

Furthermore, the resin layer 32 may be a semi-cured material including the resin composition as described above, or may be a material including the uncured resin composition. That is, the resin-coated metal foil 31 may be a resin-coated metal foil including a resin layer including a semi-cured material including the resin composition (the resin composition described above in the B stage) and a metal foil, or may be a resin-coated metal foil including a resin layer including the resin composition described above before curing (the resin composition described above in the A stage) and a metal foil. Furthermore, the resin layer may contain the resin composition or the semi-cured material including the resin composition, and may or may not contain the fiber substrate. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried. Furthermore, the fiber substrate may be the same as the fiber substrate of the prepreg.

The metal foil may be any metal foil that can be used for metal-clad laminates without limitation. Examples of the metal foil include copper foil and aluminum foil.

The aforementioned metal foil 31 with resin and the aforementioned film 41 with resin may also be provided with a covering film etc. as required. By providing the covering film, it is possible to prevent foreign matter from being mixed in. The aforementioned covering film is not particularly limited, and examples thereof include polyolefin film, polyester film, polymethylpentene film, and films formed by providing a release agent layer on these films.

The method for manufacturing the aforementioned resin-coated metal foil 31 is not particularly limited as long as the aforementioned resin-coated metal foil 31 can be manufactured. The aforementioned resin-coated metal foil 31 can be manufactured by applying the aforementioned varnish-like resin composition (resin varnish) on the metal foil 13 and heating it. The varnish-like resin composition can be applied to the metal foil 13 by using a rod coater, for example. The applied resin composition can be heated under the conditions of, for example, 40° C. to 180° C. for 1 minute to 10 minutes. The heated resin composition is formed on the metal foil 13 as an uncured resin layer 32. In addition, the organic solvent can be volatilized from the resin varnish by the aforementioned heating, thereby reducing or removing the organic solvent.

[Resin-attached film] Fig. 5 is a schematic cross-sectional view showing an example of a resin-attached film 41 of the present embodiment.

As shown in FIG5 , the resin-attached film 41 of the present embodiment comprises a resin layer 42 including the resin composition or a semi-cured product of the resin composition and a support film 43. The resin-attached film 41 comprises the resin layer 42 and the support film 43 laminated with the resin layer 42. Furthermore, the resin-attached film 41 may also comprise another layer between the resin layer 42 and the support film 43.

Furthermore, the resin layer 42 may be a semi-cured material containing the resin composition as described above, or may be a material containing the uncured resin composition. That is, the resin-attached film 41 may be a resin-attached film having a resin layer containing a semi-cured material of the resin composition (the resin composition described above in the B stage) and a supporting film, or may be a resin-attached film having a resin layer containing the resin composition described above before curing (the resin composition described above in the A stage) and a supporting film. Furthermore, the resin layer may contain the resin composition or the semi-cured material of the resin composition, and may or may not contain the fiber substrate. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried. Furthermore, the fiber substrate may be the same as the fiber substrate of the prepreg.

The supporting film 43 may be any supporting film that can be used for a resin-attached film without limitation. Examples of the supporting film include electrically insulating films such as polyester film, polyethylene terephthalate (PET) film, polyimide film, polyethylene urea film, polyetheretherketone film, polyphenylene sulfide film, polyamide film, polycarbonate film, and polyarylate film.

The aforementioned resin film 41 may also be provided with a covering film etc. as required. By providing the covering film, it is possible to prevent foreign matter from being mixed in. The aforementioned covering film is not particularly limited, and examples thereof include polyolefin film, polyester film, and polymethylpentene film.

The aforementioned support film and cover film may also be subjected to surface treatments such as matte treatment, corona treatment, mold release treatment, and roughening treatment as required.

The method for producing the aforementioned resin-attached film 41 is not particularly limited as long as the aforementioned resin-attached film 41 can be produced. The method for producing the aforementioned resin-attached film 41 may be, for example, a method of producing by applying the aforementioned varnish-like resin composition (resin varnish) on a supporting film 43 and heating it. The varnish-like resin composition may be applied to the supporting film 43, for example, by using a rod coater. The applied resin composition may be heated under conditions of, for example, 40° C. to 180° C. for 1 minute to 10 minutes. The heated resin composition is formed on the supporting film 43 as an uncured resin layer 42. In addition, the organic solvent can be volatilized from the resin varnish by the aforementioned heating, thereby reducing or removing the organic solvent.

The prepreg, resin-coated film, and resin-coated metal foil obtained using the resin composition of this embodiment have excellent low dielectric properties and high thermal conductivity in the cured product, and also have excellent adhesion, so they are very useful in industrial use. In addition, the metal-clad laminate and wiring board having an insulating layer including the cured product of the resin composition of this embodiment also have the advantages of having low dielectric properties and high thermal conductivity, and also excellent adhesion.

As described above, this specification discloses various aspects of technology, and the main technologies are summarized as follows.

The resin composition of the first aspect of the present invention is a resin composition comprising a free radical polymerizable compound (A) and an inorganic filler (B), wherein the inorganic filler (B) comprises a boron nitride filler (b1); the particle size distribution of the boron nitride filler (b1) has a cumulative value of 10% particle size (D10) of 0.5-2.0µm, a cumulative value of 50% particle size (D50) of 4.0-6.0µm, and a cumulative value of 90% particle size (D90) of 6.5-20.0µm.

The resin composition of the second aspect of the present invention is the resin composition of the first aspect, and is a resin composition in which the average aspect ratio (maximum length in the main surface/thickness in a direction perpendicular to the main surface) of the boron nitride filler (b1) is 6-20.

The resin composition of the third aspect of the present invention is the resin composition of the first or second aspect, and is the following resin composition: the free radical polymerizable compound (A) includes at least one selected from the group consisting of a polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule, a hydrocarbon compound having a carbon-carbon unsaturated double bond in the molecule, a maleimide compound and an allyl compound.

The resin composition of the fourth aspect of the present invention is the resin composition of any one of the first to third aspects, and is a resin composition wherein the content of the inorganic filler (B) is 5 to 70 parts by volume relative to 100 parts by volume of the radical polymerizable compound (A).

The resin composition of the fifth aspect of the present invention is the resin composition of any one of the first to fourth aspects, and is the following resin composition: relative to 100 parts by volume (solid content) of the free radical polymerizable compound (A), the content of the boron nitride filler (b1) is 5-50 parts by volume.

The resin composition of the sixth aspect of the present invention is a resin composition in any one of the first to fifth aspects, wherein the inorganic filler (B) includes a silica filler (b2).

The resin composition of the seventh aspect of the present invention is the resin composition of the sixth aspect, and is the following resin composition: in the inorganic filler (B), the volume content ratio of the boron nitride filler (b1) to the silica filler (b) (the volume content of the boron nitride filler (b1)/the volume content of the silica filler (b)) is 1-4.

The resin composition of the eighth aspect of the present invention is the resin composition of any one of the first to seventh aspects, and further comprises a phosphorus compound (C).

The resin composition of the 9th aspect of the present invention is the resin composition of the 8th aspect, and is the following resin composition: the phosphorus compound (C) includes: a miscible phosphorus compound (c1) that is miscible with the free radical polymerizable compound (A); and an incompatible phosphorus compound (c2) that is incompatible with the free radical polymerizable compound (A).

The resin composition of the tenth aspect of the present invention is the resin composition of the ninth aspect, wherein the compatible phosphorus compound (c1) comprises at least one selected from the group consisting of phosphate compounds, phosphazene compounds, phosphite compounds and phosphine compounds.

The resin composition of the 11th aspect of the present invention is the resin composition of the 9th aspect, and is the following resin composition: the incompatible phosphorus compound (c2) includes at least one selected from the group consisting of isophosphite compounds, polyphosphate compounds, phosphonium salt compounds and phosphine oxide compounds.

The resin composition of the twelfth aspect of the present invention is the resin composition of any one of the first to eleventh aspects, and is a resin composition having a thermal conductivity of 1.0 W/mK or more in the cured product and a relative dielectric constant of 4.0 or less in the cured product.

The prepreg of the 13th aspect of the present invention comprises: a resin composition of any one of the 1st to 12th aspects or a semi-cured product of the resin composition; and a fiber substrate.

The resin-attached film of the 14th aspect of the present invention comprises: a resin layer comprising the resin composition of any one of the 1st to 12th aspects or a semi-hardened product of the aforementioned resin composition; and a supporting film.

The resin-coated metal foil of the fifteenth aspect of the present invention comprises: a resin layer comprising the resin composition of any one of the first to twelfth aspects or a semi-cured product of the resin composition; and a metal foil.

The metal-clad laminate of the 16th aspect of the present invention comprises: an insulating layer comprising a cured product of the resin composition of any one of the 1st to 12th aspects or a cured product of the prepreg of the 13th aspect; and a metal foil.

The wiring board of the 17th aspect of the present invention comprises: an insulating layer including a cured product of the resin composition of any one of the 1st to 12th aspects or a cured product of the prepreg of the 13th aspect; and wiring.

The present invention is described in more detail below by way of examples, but the scope of the present invention is not limited thereto.

[Examples] [Examples 1 to 9 and Comparative Examples 1 to 8] The components used in preparing the resin composition in this embodiment are described.

<Free radical polymerizable compound (A)> (Free radical polymerizable compound (A1)) ・PPE1: Polyphenylene ether compound having a methacryloyl group at the end (SA9000 manufactured by SABIC Innovative Plastics, weight average molecular weight Mw2000, number of terminal functional groups 2)

・PPE2: Modified polyphenylene ether obtained by reacting polyphenylene ether with chloromethylstyrene. Specifically, it is a modified polyphenylene ether obtained by reacting in the following manner.

First, 200 g of polyphenylene ether (SA90 manufactured by SABIC Innovative Plastics, with two terminal hydroxyl groups and a weight average molecular weight of Mw1700), 30 g of a mixture of p-chloromethylstyrene and m-chloromethylstyrene in a mass ratio of 50:50 (chloromethylstyrene manufactured by Tokyo Chemical Industry Co., Ltd.: CMS), 1.227 g of tetrabutylammonium bromide as a phase transfer catalyst, and 400 g of toluene were added to a 1-liter three-necked flask equipped with a temperature regulator, a stirring device, a cooling device, and a dropping funnel, and stirred. Then, stirring was continued until polyphenylene ether, chloromethylstyrene, and tetrabutylammonium bromide were dissolved in toluene. At this time, heating was slowly applied until the final liquid temperature reached 75°C. Then, an aqueous sodium hydroxide solution (20 g sodium hydroxide/20 g water) as an alkaline metal hydroxide was dripped into the solution over a period of 20 minutes. Then, it was further stirred at 75°C for 4 hours. Next, the contents of the flask were neutralized with 10% by mass hydrochloric acid, and a large amount of methanol was added. By doing so, a precipitate was produced in the liquid in the flask. That is, the product contained in the reaction solution in the flask was precipitated again. Then, the precipitate was taken out by filtration, washed 3 times with a mixed solution of methanol and water in a mass ratio of 80:20, and then dried at 80°C for 3 hours under reduced pressure.

The obtained solid was analyzed by ¹ H-NMR (400 MHz, CDCl ₃ , TMS). As a result of NMR measurement, a peak derived from vinyl benzyl/ethenyl benzyl was confirmed at 5-7 ppm. Thus, it was confirmed that the obtained solid was a modified polyphenylene ether compound having vinyl benzyl/ethenyl benzyl as the aforementioned substituent at the molecular end. Specifically, it was confirmed that it was a vinylbenzylated polyphenylene ether. The obtained modified polyphenylene ether compound was a modified polyphenylene ether compound represented by the above formula (14), Y was a dimethylmethylene group (represented by formula (12) and R ₃₃ and R ₃₄ in formula (12) were methyl groups), Z was a phenylene group, R ₁ to R ₃ were hydrogen atoms, and n was 1.

Furthermore, the terminal functional groups of the modified polyphenylene ether were measured in the following manner.

First, weigh the modified polyphenylene ether correctly. Let the weight at this time be X (mg). Then, dissolve the weighed modified polyphenylene ether in 25 mL of dichloromethane, and add 100 µL of 10 mass % tetraethylammonium hydroxide (TEAH) ethanol solution (TEAH: ethanol (volume ratio) = 15:85) to the solution, and use a UV spectrophotometer (UV-1600 manufactured by Shimadzu Corporation) to measure the absorbance (Abs) at 318 nm. Then, calculate the number of terminal hydroxyl groups of the modified polyphenylene ether from the measurement results using the following formula.

Residual OH content (µmol/g) = [(25×Abs)/(ε×OPL×X)] ×10 ⁶ Here, ε is the absorption coefficient, which is 4700L/mol・cm. OPL is the optical path length of the test cell, which is 1cm.

Then, from the result that the residual OH amount (terminal hydroxyl group number) of the modified polyphenyl ether calculated is almost zero, it can be seen that the hydroxyl group of the polyphenyl ether before modification has been almost modified. Therefore, it can be seen that the amount of reduction from the terminal hydroxyl group number of the polyphenyl ether before modification is the terminal hydroxyl group number of the polyphenyl ether before modification. In other words, it can be seen that the terminal hydroxyl group number of the polyphenyl ether before modification is the terminal functional group number of the modified polyphenyl ether. In other words, the terminal functional group number is 2.

The molecular weight distribution of the modified polyphenylene ether was measured by GPC. The weight average molecular weight (Mw) was calculated from the obtained molecular weight distribution. As a result, Mw was 1900.

(Free radical polymerizable compound (A2)) ・Allyl compound: Triallyl isocyanurate (TAIC) (TAIC manufactured by Nippon Chemical Industry Co., Ltd.) ・Vinyl compound: Divinylbenzene (DVB manufactured by Nippon Steel & Sumitomo Metal Corporation)

<Inorganic filler (B)> (Boron nitride filler (b1)) Boron nitride filler 1: "SGP" manufactured by Denka Co., Ltd. Boron nitride filler 2: "AP10S" manufactured by MARUKA Co., Ltd. Boron nitride filler 3: "ABN-5" manufactured by Baitu High-Tech Materials Co., Ltd. (Silicon dioxide filler (b2)) Silicon dioxide filler: "FB-7SDC" manufactured by Denka Co., Ltd. (Other inorganic fillers) Alumina filler: "DAW-03DC" manufactured by Denka Co., Ltd.

<Phosphorus compound (C)> ・Compatible phosphorus compound (c1): Aromatic condensed phosphate compound (manufactured by Daihachi Chemical Industry Co., Ltd., PX-200) ・Incompatible phosphorus compound (c2): Diphenylphosphine oxide compound, manufactured by Shinichi Chemical Co., Ltd., "PQ60"

<Reaction initiator> ・Organic peroxide: PBP (1,3-bis(butylperoxyisopropyl)benzene; Perbutyl P manufactured by NOF Corporation)

(Preparation method) First, add the components other than the inorganic filler to toluene in the composition listed in Table 1 in parts by mass (only the inorganic filler is in parts by volume) and mix. Stir the mixture for 60 minutes. Then, add the filler (parts by mass) to the resulting liquid, adjust the amount of toluene added so that the solid component concentration of the dispersed resin composition becomes 65 parts by mass, and stir for 60 minutes to disperse the filler once. Then, disperse the inorganic filler twice using a bead mill to obtain a varnish-like resin composition (varnish).

Next, the following procedure was performed to obtain an evaluation substrate (cured product of the prepreg).

The obtained varnish was impregnated into a fiber substrate (glass cloth: Asahi Kasei Co., Ltd. #1078 type, L glass), and then dried at 120°C for 3 minutes to produce a prepreg. Then, each of the obtained prepregs was stacked, and copper foil (Furukawa Electric Co., Ltd. "FV-WS" copper foil thickness: 35µm) was attached to both sides, heated to 200°C at a heating rate of 4°C/min, and heated and pressed at 200°C, 120 minutes, and a pressure of 3MPa to produce a copper-clad laminate with a thickness of 130µm.

<Test Example 1> In the measurement of thermal conductivity described below, cured prepregs with three different sheet thicknesses were used, and in the evaluation test of dielectric properties (relative dielectric constant), a copper-clad laminate with four prepregs stacked and copper foil removed (cured prepreg) was used.

Regarding formability and adhesion, 4 sheets of the prepregs prepared above were stacked to produce a copper-clad laminate with a thickness of 0.5 mm and a copper foil thickness of 18 µm. A grid pattern with a residual copper rate of 50% was formed on the surface. The laminate was used as a core material and prepregs were placed on both sides for 2-hour forming. Then, the copper foil on the surface was etched. In the formability and adhesion test, the laminate (evaluation substrate 1) obtained by the above method was used.

The evaluation samples prepared in the above manner were evaluated by the following method.

[Particle size distribution of boron nitride filler] The particle size distribution of the boron nitride filler in each embodiment and comparative example is obtained by measuring using the laser diffraction/scattering particle size distribution measuring device LA-960V2 (manufactured by Horiba, Ltd.). The specifications of the device are as follows. Measurement principle: Mie scattering theory Measurement method: flow measurement Range: 0.01µm~5000µm Light source: LD (650nm), about 5mW, LED (405mm), about 3mW Detector: 1 ring-shaped 64-segment silicon photodiode, 5 4ch array detectors, 3 silicon photodetectors Refractive index: 2.250-0.005i

The specifications of the measuring part (circulation system) are as follows. Dispersion: Ultrasonic probe Circulation: Centrifugal pump Agitation: Rotating blade Flow cell material: Synthetic quartz

The particle size distribution measurement conditions are as follows.

Toluene was used as the dispersion solvent, and each test sample was placed into the flow cell through the sample channel, and laser diffraction/scattering type particle size distribution measurement was performed under stirring.

The particle size distribution was analyzed and calculated using the analysis software LA-960 for Windows that comes with the LA-960V2. Then, the peak value in the particle size distribution was calculated using the volume ratio of the measured particle size distribution.

[Average aspect ratio of boron nitride filler] The aspect ratio is defined as the maximum length in the main surface / thickness in the direction perpendicular to the main surface. Using a scanning electron microscope (Flex SEM1000II manufactured by Hitachi High-Technologies), the maximum length in the main surface of the boron nitride filler particles / thickness in the direction perpendicular to the main surface were measured with n=10, and the average aspect ratio was calculated.

[Dielectric properties (relative dielectric constant)] The relative dielectric constant (Dk) of the evaluation substrate (cured prepreg) at 10 GHz was measured using the cavity resonator perturbation method. Specifically, a network analyzer (N5230A manufactured by Keysight Technologies) was used to measure the dielectric tangent of the evaluation substrate at 10 GHz. The pass standard in this embodiment is set to Dk < 4.0.

[Formability] Regarding formability, the evaluation substrate 1 described above was observed with the naked eye, and those with pores observed were evaluated as "unqualified", and those without pores observed were evaluated as "qualified".

[Adhesion] Regarding adhesion, the evaluation substrate 1 described above was used to evaluate the boiling solder heat resistance. First, the evaluation substrate 1 was boiled in hot water for 4 hours, and then immersed in a 288°C solder bath for 20 seconds. The sample after the immersion was visually observed to see if it expanded. Those that expanded were judged as "unqualified", and those that did not expand were judged as "qualified".

[Thermal conductivity] The thermal conductivity of the obtained evaluation substrate (cured product of prepreg) was measured by following the method of ASTM D5470. Specifically, the thermal conductivity of the obtained evaluation substrate (cured product of 4 stacked prepregs) was measured using a thermal characteristics evaluation device (T3Ster DynTIM Tester manufactured by Mentor Graphics). The pass standard of thermal conductivity in this embodiment is set to 1.0W/m・K or more.

The results of the above evaluations are shown in Table 1.

[Table 1]

(Investigation) As can be seen from Table 1, in the embodiments using the resin composition of the present invention, it is confirmed that a cured product having low dielectric properties (relative dielectric constant) (Dk < 4.0) and high thermal conductivity (1.0 W/m・K or more) can be provided, and a resin composition having adhesion under more stringent conditions than before can be provided.

On the other hand, in Comparative Examples 1 to 2, 5 and 7, which used boron nitride fillers whose particle size distributions D10, D50 and D90 were all larger than the provisions of the present invention, the moldability was poor. In addition, in Comparative Examples 3 to 4 and 6, which used boron nitride fillers whose particle size distributions D10, D50 and D90 were all smaller than the provisions of the present invention, adhesion at a level sufficient for substrate manufacturing could not be obtained. Moreover, in Comparative Example 8, which did not contain a boron nitride filler, sufficient thermal conductivity could not be obtained.

This application is based on Japanese Patent Application No. 2023-57185 filed on March 31, 2023, and the contents are incorporated into this application.

In order to explain the present invention, the present invention has been appropriately and fully described in the foregoing description with reference to specific examples or drawings, etc., but it should be understood that the foregoing description can be easily modified and/or improved by a person having ordinary knowledge in the relevant technical field. Therefore, as long as the modified or improved form implemented by a person having ordinary knowledge in the relevant technical field does not deviate from the level of the scope of the claim stated in the patent application, the modified or improved form can be interpreted as being included in the scope of the claim.

Industrial Applicability This invention has broad industrial applicability in the technical fields of electronic materials, electronic devices, optical devices, etc.

1: Prepreg 2: Resin composition or semi-cured resin composition 3: Fiber substrate 11: Metal-clad laminate 12: Insulation layer 13: Metal foil 14: Wiring 21: Wiring board 31: Resin-coated metal foil 32,42: Resin layer 41: Resin-coated film 43: Support film

FIG. 1 is a schematic cross-sectional view showing an example of a prepreg according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of a wiring board according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing an example of a metal foil with a resin according to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing an example of a film with a resin according to an embodiment of the present invention.

1: Prepreg

2: Resin composition or semi-hardened resin composition

3: Fiber substrate

Claims (19)

A resin composition comprises a free radical polymerizable compound (A) and an inorganic filler (B); The inorganic filler (B) comprises a boron nitride filler (b1); The particle size distribution of the boron nitride filler (b1) has a cumulative value of 10% particle size (D10) of 0.5-2.0µm, a cumulative value of 50% particle size (D50) of 4.0-6.0µm, and a cumulative value of 90% particle size (D90) of 6.5-20.0µm. The resin composition of claim 1, wherein the average aspect ratio (maximum length in the main surface/thickness in a direction perpendicular to the main surface) of the boron nitride filler (b1) is 6-20. The resin composition of claim 1, wherein the free radical polymerizable compound (A) comprises at least one selected from the group consisting of a polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule, a hydrocarbon compound having a carbon-carbon unsaturated double bond in the molecule, a maleimide compound and an allyl compound. The resin composition of claim 1, wherein the content of the inorganic filler (B) is 5-70 parts by volume relative to 100 parts by volume of the free radical polymerizable compound (A). The resin composition of claim 1, wherein the content of the boron nitride filler (b1) is 5-50 parts by volume relative to 100 parts by volume of the free radical polymerizable compound (A). The resin composition of claim 1, wherein the inorganic filler (B) comprises a silica filler (b2). The resin composition of claim 6, wherein in the inorganic filler (B), the volume content ratio of the boron nitride filler (b1) to the silicon dioxide filler (b) (the volume content of the boron nitride filler (b1)/the volume content of the silicon dioxide filler (b)) is 1-4. The resin composition of claim 1, comprising a phosphorus compound (C). The resin composition of claim 8, wherein the phosphorus compound (C) comprises: a compatible phosphorus compound (c1) that is compatible with the free radical polymerizable compound (A); and an incompatible phosphorus compound (c2) that is incompatible with the free radical polymerizable compound (A). The resin composition of claim 9, wherein the compatible phosphorus compound (c1) comprises at least one selected from the group consisting of phosphate compounds, phosphazene compounds, phosphite compounds and phosphine compounds. The resin composition of claim 9, wherein the incompatible phosphorus compound (c2) comprises at least one selected from the group consisting of isophosphite compounds, polyphosphate compounds, phosphonium salt compounds and phosphine oxide compounds. The resin composition of claim 1, wherein the thermal conductivity of the cured product is greater than 1.0 W/mK, and the relative dielectric constant of the cured product is less than 4.0. A prepreg comprising: a resin composition as defined in any one of claims 1 to 12 or a semi-cured product of the resin composition; and a fiber substrate. A resin-coated film comprises: a resin layer comprising the resin composition of any one of claims 1 to 12 or a semi-hardened product of the resin composition; and a supporting film. A resin-coated metal foil comprises: a resin layer comprising the resin composition of any one of claims 1 to 12 or a semi-cured product of the resin composition; and a metal foil. A metal-clad laminate comprises: an insulating layer comprising a hardened product of the resin composition of any one of claims 1 to 12; and a metal foil. A wiring board comprising: an insulating layer comprising a cured product of the resin composition of any one of claims 1 to 12; and wiring. A metal-clad laminate comprises: an insulating layer comprising a cured product of the prepreg of claim 13; and a metal foil. A wiring board comprises: an insulating layer comprising a cured product of the prepreg as claimed in claim 13; and wiring.

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