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

Abstract

One aspect of the present invention relates to a resin composition containing: a resin component containing a radically polymerizable compound (A); and a boron nitride filler (B), the boron nitride filler (B) containing 10-50 mass% of an aggregated boron nitride filler (b1) relative to the total amount of the boron nitride filler (B), the thermal conductivity of the cured product being 1.0 W / mK or more, and the relative permittivity of the cured product being 4.0 or less.

Description

Technical Field

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

[0002] For various electronic devices, with the increasing volume of information processing, mounting technologies such as high integration of semiconductor devices, high-density wiring, and multi-layering are becoming increasingly advanced. Furthermore, wiring boards used in various electronic devices are seeking solutions for high-frequency applications, such as millimeter-wave radar substrates used in automotive applications. For wiring boards used in various electronic devices, reducing signal transmission losses is required to improve signal transmission speed; this requirement is particularly important for wiring boards used in high-frequency applications. To meet this requirement, the substrate material used to construct the wiring boards used in various electronic devices is required to have a low dielectric constant and low dielectric loss factor.

[0003] As such a substrate material, for example, a PPE-containing resin composition containing PPE (polyphenylene oxide), a cross-linking curable compound, a phosphaphenanthrene derivative, and silica has been proposed (Patent Document 1).

[0004] On the other hand, for electronic materials such as PA (power amplifier) ​​substrates used in base stations, in addition to requiring low dielectric constant and dielectric loss factor, high thermal conductivity is also required. In this regard, the inorganic filler (silicon dioxide) contained in the resin composition of Patent Document 1 sometimes fails to achieve sufficient thermal conductivity.

[0005] In response to this, one method proposed to date for improving the thermal conductivity of resin compositions is the use of boron nitride as an inorganic filler with high thermal conductivity (Patent Document 2).

[0006] However, while the boron nitride filler described in Patent Document 2 does improve the thermal conductivity of the resin composition, the flake-shaped boron nitride described therein has the disadvantage of being difficult to highly fill. This is because increasing the amount of flake-shaped boron nitride to simultaneously achieve a thin substrate and high thermal conductivity results in poor formability.

[0007] From the perspective of interfacial resistance between resin and filler, generally, the larger the particle size of a heat-dissipating filler, the higher its thermal conductivity. However, since flake boron nitride is oriented and accumulates in the XY direction, its thermal conductivity is not significantly increased. From the orientation point of view, smaller flake boron nitride particle size is more advantageous; however, this increases the specific surface area, which in turn leads to a significant increase in varnish viscosity, thus worsening the processability of the substrate during molding.

[0008] The present application has been made in view of the circumstances, and aims to provide a resin composition capable of obtaining a cured product having low dielectric properties (low dielectric constant) and high thermal conductivity, and excellent moldability. Furthermore, the present application 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 resin composition.

[0009] Prior Art Documents

[0010] Patent Documents

[0011] Patent Document 1: Japanese Patent Publication No. 2015-67700

[0012] Patent Document 2: Japanese Patent Publication No. 2013-159698 SUMMARY

[0013] The present inventors have conducted various studies, and as a result, have found that the above object can be achieved by the following configuration, and have further repeated studies, thereby completing the present application.

[0014] That is, one aspect of the present application relates to a resin composition containing: a resin component containing a radical polymerizable compound (A); and a boron nitride filler (B), wherein the boron nitride filler (B) contains, in an amount of 10 to 50% by mass relative to the total amount of the boron nitride filler (B), an aggregated boron nitride filler (bl), the thermal conductivity of a cured product is 1.0 W / mK or more, and the relative dielectric constant of the cured product is 4.0 or less. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a schematic cross-sectional view showing an example of a prepreg related to an embodiment of the present application.

[0016] Figure 2 is a schematic cross-sectional view showing an example of a metal-clad laminate related to an embodiment of the present application.

[0017] Figure 3 is a schematic cross-sectional view showing an example of a wiring board related to an embodiment of the present application.

[0018] Figure 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil related to an embodiment of the present application.

[0019] Figure 5 is a schematic cross-sectional view showing an example of a resin-coated film related to an embodiment of the present application. DETAILED DESCRIPTION

[0020] Hereinafter, the embodiments to which the present application relates will be specifically described, but the present application is not limited by these descriptions.

[0021] [Resin composition]

[0022] The embodiment of the present application relates to a resin composition containing: a resin component containing a radical polymerizable compound (A); and a boron nitride filler (B), wherein the boron nitride filler (B) contains 10 to 50 mass% of agglomerated boron nitride filler (bl) with respect to the total amount of the boron nitride filler (B), the thermal conductivity of a cured product is 1.0 W / mK or more, and the relative dielectric constant of the cured product is 4.0 or less. Note that the relative dielectric constant is the relative dielectric constant at a frequency of 10 GHz.

[0023] According to the above configuration, a resin composition capable of obtaining a cured product having low dielectric properties (particularly, relative dielectric constant: Dk) and high thermal conductivity, and excellent moldability can be obtained. It is considered that this is because the agglomerated boron nitride, which is obtained by agglomerating primary particles of boron nitride, is contained as the boron nitride filler having high thermal conductivity, and thus a resin composition having excellent moldability and handleability can be obtained even if the inorganic filler is highly filled.

[0024] That is, the resin composition of the present embodiment can balance the high thermal conductivity and the low dielectric properties of the cured product thereof, and also has excellent moldability, and thus is very useful from an industrial viewpoint. Furthermore, by using the resin composition, a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board having the above-described properties can be provided.

[0025] First, each component of the resin composition of the present embodiment will be described. The resin composition of the present embodiment contains a resin component containing a radical polymerizable compound (A). Note that the resin component herein refers to the organic resin component in the resin composition.

[0026] (Radical polymerizable compound (A))

[0027] The radical polymerizable compound (A) of the present embodiment is not particularly limited as long as it is a compound having radical polymerizability. As a more specific radical polymerizable compound (A), it is preferable to contain, for example, 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.

[0028] Further, as the radical polymerizable compound (A), it is preferable to include, for example, a compound having a reactive unsaturated group, a compound having a maleimide group, and the like, radical polymerizable compound (A1), and it is further preferable to include not only the radical polymerizable compound (A1), but also a radical polymerizable compound (other radical polymerizable compound) (A2) other than the radical polymerizable compound (A1). Hereinafter, each will be described.

[0029] (Radical polymerizable compound (A1))

[0030] First, the radical polymerizable compound (A1) will be described.

[0031] The radical polymerizable compound (A1) used in the present embodiment is not particularly limited as long as it is a compound having radical polymerizability. For example, a compound having a reactive unsaturated group such as a carbon-carbon unsaturated double bond, a compound having a maleimide group, and the like can be exemplified. By using this radical polymerizable compound (A1), a resin composition capable of obtaining a cured product having low dielectric properties can be obtained.

[0032] The molecular weight of the radical polymerizable compound (A1) is preferably around 100 to 3000 in terms of weight average molecular weight. Note that the weight average molecular weight is a value obtained by measuring with a usual molecular weight measuring method, and specifically, a value measured using gel permeation chromatography (GPC) or the like can be exemplified.

[0033] As a more specific radical polymerizable compound (A1), it is preferable to include, for example, 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. Hereinafter, a more detailed description thereof will be given.

[0034] • Polyphenylene ether compound

[0035] As the polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule, for example, a polyphenylene ether compound having a group represented by the following formula (1) or formula (2), and the like can be exemplified. It is considered that by containing such a modified polyphenylene ether compound, a resin composition capable of obtaining a cured product having low dielectric properties and high heat resistance is obtained.

[0036]

[0037] In formula (1), s represents an integer of 0 to 10. Further, Z represents an arylene group. Further, R1 to R3 are each independent. That is, R1 to R3 can each be the same group, or can each be a different group. Further, R1 to R3 represent a hydrogen atom or an alkyl group.

[0038] Note that, in formula (1), in the case where s is 0, it means that Z is directly bonded to the terminal of the polyphenylene ether.

[0039] The arylene group of Z is not particularly limited. As the arylene group, a monocyclic aromatic group such as phenylene; a polycyclic aromatic group in which the aromatic group is not monocyclic but polycyclic such as naphthalene; and the like can be exemplified. Further, the arylene group also includes a derivative in which a hydrogen atom bonded to the aromatic ring is substituted with a functional group such as an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. Further, the alkyl group is not particularly limited, and for example, an alkyl group having a carbon number of 1 to 18 is preferable, and an alkyl group having a carbon number of 1 to 10 is more preferable. Specifically, a methyl group, an ethyl group, a propyl group, a hexyl group, a decyl group, and the like can be exemplified.

[0040]

[0041] In formula (2), R4represents a hydrogen atom or an alkyl group. The alkyl group is not particularly limited, and for example, an alkyl group having a carbon number of 1 to 18 is preferable, and an alkyl group having a carbon number of 1 to 10 is more preferable. Specifically, a methyl group, an ethyl group, a propyl group, a hexyl group, a decyl group, and the like can be exemplified.

[0042] As a preferable specific example of the substituent represented by formula (1), a substituent including a vinylbenzyl group can be exemplified. As the substituent including a vinylbenzyl group, a substituent represented by formula (3) described below can be exemplified. Further, as the substituent represented by formula (2), an acrylate group, a methacrylate group, and the like can be exemplified.

[0043]

[0044] More specifically, as the substituent, a vinylbenzyl group (vinylbenzyl group) such as a p-vinylbenzyl group and a m-vinylbenzyl group, a vinylphenyl group, an acrylate group, a methacrylate group, and the like can be exemplified.

[0045] In the resin composition of the present embodiment, it is more preferable that the polyphenylene ether compound has a group represented by formula (2). This is because, by this, the reactivity with the crosslinking agent is improved, and a resin cured product having high heat resistance is easily obtained.

[0046] The polyphenylene ether compound has a polyphenylene ether chain in the molecule, and for example, it is preferable to have a repeating unit represented by formula (4) described below in the molecule.

[0047]

[0048] In formula (4), t represents 1 to 50. Further, R5to R8are each independent. That is, R5to R8may be the same group, or can be different groups. Further, R5to R8represent 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. Among them, a hydrogen atom and an alkyl group are preferred.

[0049] Among R5to R8, as each of the listed functional groups, specifically, the following groups can be listed.

[0050] The alkyl group is not particularly limited, and for example, an alkyl group having a carbon number of 1 to 18 is preferred, and an alkyl group having a carbon number of 1 to 10 is more preferred. Specifically, for example, a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group, and the like can be listed.

[0051] The alkenyl group is not particularly limited, and for example, an alkenyl group having a carbon number of 2 to 18 is preferred, and an alkenyl group having a carbon number of 2 to 10 is more preferred. Specifically, for example, a vinyl group, an allyl group, and a 3-butenyl group, and the like can be listed.

[0052] The alkynyl group is not particularly limited, and for example, an alkynyl group having a carbon number of 2 to 18 is preferred, and an alkynyl group having a carbon number of 2 to 10 is more preferred. Specifically, for example, an ethynyl group and a prop-2-yn-1-yl group (propargyl group), and the like can be listed.

[0053] The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, and for example, an alkylcarbonyl group having a carbon number of 2 to 18 is preferred, and an alkylcarbonyl group having a carbon number of 2 to 10 is more preferred. Specifically, for example, an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a neopentanoyl group, a hexanoyl group, an octanoyl group, and a cyclohexylcarbonyl group, and the like can be listed.

[0054] The alkenylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkenyl group, and for example, an alkenylcarbonyl group having a carbon number of 3 to 18 is preferred, and an alkenylcarbonyl group having a carbon number of 3 to 10 is more preferred. Specifically, for example, an acryloyl group, a methacryloyl group, and a crotonoyl group, and the like can be listed.

[0055] 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 a carbon number of 3 to 18 is preferred, and an alkynylcarbonyl group having a carbon number of 3 to 10 is more preferred. Specifically, for example, a propynoyl group, and the like can be listed.

[0056] The average number of the substituents (the number of terminal functional groups) possessed by each molecule of the polyphenylene ether compound at the molecular terminal is not particularly limited. Specifically, it is preferably 1 to 5, more preferably 1 to 3, and further preferably 1.5 to 3. If the number of terminal functional groups is too small, there is a tendency that a cured product having sufficient heat resistance cannot be obtained. In addition, if the number of terminal functional groups is too large, the reactivity becomes too high, and there is a risk that an adverse condition such as a decrease in storage property of the resin composition or a decrease in flowability of the resin composition can occur. That is, if the polyphenylene ether compound is used, a problem in moldability such as formation of a void or the like, which is a molding defect, can occur due to insufficient flowability or the like, and it is difficult to obtain a printed wiring board having high reliability.

[0057] Note that the number of terminal functional groups of the polyphenylene ether compound can be exemplified by a value indicating the average of the substituents present in each molecule of all the modified polyphenylene ether compounds in 1 mole of the polyphenylene ether compound, and the like. The number of terminal functional groups can be measured, for example, by measuring the number of hydroxyl groups remaining in the obtained modified polyphenylene ether compound and calculating the amount of decrease in the number of hydroxyl groups as compared with the polyphenylene ether before modification. The amount of decrease in the number of hydroxyl groups as compared with the polyphenylene ether before modification is the number of terminal functional groups. Furthermore, the method for measuring the number of hydroxyl groups remaining in the modified polyphenylene ether compound can be such that a quaternary ammonium salt (tetraethylammonium hydroxide) that associates with a hydroxyl group is added to a solution of the modified polyphenylene ether compound, and the UV absorbance of the mixed solution is measured.

[0058] As the polyphenylene ether compound of the present embodiment, a modified polyphenylene ether compound represented by the following formula (5) and a modified polyphenylene ether compound represented by the following formula (6) can be exemplified. In addition, as the polyphenylene ether compound of the present embodiment, these modified polyphenylene ether compounds can be used alone, or the two types of modified polyphenylene ether compounds can be used in combination.

[0059]

[0060] In formula (5) and formula (6), R9 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 formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. X1 and X2 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). In addition, in formula (6), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms.

[0061]

[0062] In formula (7) and formula (8), m and n each represent 0 to 20. R25 ~R 28 and R 29 ~R 32 each independently represents 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.

[0063] The modified polyphenylene ether compound represented by the formula (5) and the modified polyphenylene ether compound represented by the formula (6) are not particularly limited as long as they are compounds satisfying the above constitution. Specifically, in the formula (5) and the formula (6), R9to R 16 and R 17 ~R 24 each independently. That is, R9to R 16 and R 17 ~R 24 may be the same group or different groups, respectively. Furthermore, R9to R 16 and R 17 ~R 24 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. Of these, a hydrogen atom and an alkyl group are preferred.

[0064] In the formula (7) and the formula (8), m and n each preferably represent 0 to 20 as described above. Furthermore, for m and n, the total value of m and n preferably represents a numerical value of 1 to 30. Therefore, it is more preferred that m represents 0 to 20, n represents 0 to 20, and the total of m and n represents 1 to 30. Furthermore, R 25 ~R 28 and R 29 ~R 32 each independently. That is, R 25 ~R 28 and R 29 ~R 32 may be the same group or different groups, respectively. Furthermore, R 25 ~R 28 and R 29 ~R 32 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. Of these, a hydrogen atom and an alkyl group are preferred.

[0065] R9to R 32 are the same as R5to R8in the above formula (4).

[0066] In the formula (6), Y is a linear, branched, or cyclic hydrocarbon having a carbon number of 20 or less as described above. As Y, a group represented by the following formula (9) or the like can be exemplified.

[0067]

[0068] In the formula (9), R 33 and R 34 each independently represents a hydrogen atom or an alkyl group. As the alkyl group, for example, a methyl group or the like can be mentioned. Further, as the group represented by the formula (9), for example, a methylene group, a methylmethylene group, and a dimethylmethylene group, among which a dimethylmethylene group is preferred, can be mentioned.

[0069] In the formula (5) and the formula (6), X1and X2each independently represent a substituent having a carbon-carbon unsaturated double bond. As the substituent X1and X2, there is no particular limitation as long as it is a substituent having a carbon-carbon unsaturated double bond. As the substituent X1and X2, for example, the substituent represented by the above formula (1) and the substituent represented by the above formula (2), among others, can be mentioned. Note that in the modified polyphenylene ether compound represented by the formula (5) and the modified polyphenylene ether compound represented by the formula (6), X1and X2may be the same substituent or different substituents.

[0070] As a more specific example of the modified polyphenylene ether compound represented by the formula (5), for example, a modified polyphenylene ether compound represented by the following formula (10), among others, can be mentioned.

[0071]

[0072] As a more specific example of the modified polyphenylene ether compound represented by the formula (6), for example, a modified polyphenylene ether compound represented by the following formula (11) and a modified polyphenylene ether compound represented by the following formula (12), among others, can be mentioned.

[0073]

[0074] In the above formula (10) to formula (11), m and n are the same as m and n in the above formula (7) and the above formula (8). Further, in the above formula (10) and the above formula (11), R1to R3, p, and Z are the same as R1to R3, s, and Z in the above formula (1), respectively. Further, in the above formula (11) and the above formula (12), Y is the same as Y in the above formula (9). Further, in the above formula (12), R4is the same as R4in the above formula (2).

[0075] It is considered that by using the modified polyphenylene ether compound as described above, it is possible to maintain low dielectric properties such as low dielectric constant and excellent heat resistance, and also to improve Tg and adhesion.

[0076] Note that the modified polyphenylene ether compound can be used alone or in combination of two or more.

[0077] The polyphenylene ether compound used in the resin composition of the present embodiment can be synthesized by a publicly known method or a commercially available product can be used. As commercially available products, for example, "OPE-2st1200", "OPE-2st 2200" manufactured by Mitsubishi Gas Chemical Company, Inc., "SA9000" manufactured by SABIC Innovative Plastics, and the like can be exemplified.

[0078] • a hydrocarbon compound having a carbon-carbon unsaturated double bond in the molecule

[0079] As the hydrocarbon resin that can be used in the present embodiment, there is no particular limitation as long as it is a hydrocarbon resin having an unsaturated double bond, and examples of preferred ones include a multi-functional vinyl aromatic polymer, a cyclic polyolefin resin, and a hydrocarbon resin of a vinyl aromatic compound-conjugated diene compound copolymer.

[0080] The multi-functional vinyl aromatic polymer preferably contains a polymer obtained by polymerizing at least a multi-functional vinyl aromatic compound and / or a derivative thereof, and there is no particular limitation as long as it is a polymer containing a structure derived from a multi-functional vinyl aromatic compound and / or a derivative thereof, and it can also be a polymer containing a structure derived from more than one kind of multi-functional vinyl aromatic compound and / or a derivative thereof.

[0081] Further, in addition to the multi-functional vinyl aromatic compound and / or a derivative thereof structural unit, one or more structural units derived from a reactive monomer can be contained. The reactive monomer is not particularly limited, and for example, it can be a multi-functional vinyl aromatic copolymer having a structural unit derived from a mono-vinyl aromatic compound such as styrene.

[0082] More specifically, for example, a multi-functional vinyl compound having two or more vinyl groups in the molecule can be exemplified. Also, as the multi-functional vinyl compound, for example, divinylbenzene, divinyl naphthalene, divinyl biphenyl, polybutadiene, and the like can be exemplified.

[0083] Maleimide compound

[0084] As the maleimide resin which can be used in the present embodiment, a compound having a maleimide group in the molecule can be used without particular limitation. Specifically, as the maleimide compound, a monofunctional maleimide compound having one maleimide group in the molecule, a polyfunctional maleimide compound having two or more maleimide groups in the molecule, a modified maleimide compound, and the like can be listed. As the modified maleimide compound, for example, a modified maleimide compound in which a part of the molecule is modified with an amine compound, a modified maleimide compound in which a part of the molecule is modified with an organic silicon compound, a modified maleimide compound in which a part of the molecule is modified with an amine compound and an organic silicon compound, and the like can be listed.

[0085] More specifically, for example, a maleimide compound having two or more N-substituted maleimide groups in one molecule, a maleimide compound having an indane structure, a maleimide compound having at least one selected from an alkyl group having a carbon number of 6 or more and an alkylene group having a carbon number of 6 or more, and a maleimide compound having a benzene ring in the molecule, and the like can be listed.

[0086] The maleimide compound used in the present embodiment can be a commercially available product, and for example, BMI-4000, BMI-2300, BMI-TMH, BMI-4000, BMI-5100, and the like manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., MIR-3000, MIR-5000 manufactured by Japan Epoxy Resin Co., Ltd., BMI-689, BMI-1500, BMI-3000J, BMI-5000 manufactured by Designer Molecules Inc., and the like can be used.

[0087] (Other Radical Polymerizable Compound (A2))

[0088] The resin component in the resin composition of the present embodiment can further include an other radical polymerizable compound (A2) other than the radical polymerizable compound (polyphenylene ether compound, hydrocarbon compound, maleimide compound) described above. The radical polymerizable compound (A2) is preferably a radical polymerizable compound which functions as a curing agent capable of reacting with the radical polymerizable compound (A1) (polyphenylene ether compound, hydrocarbon compound, maleimide compound, and the like) described above.

[0089] As the radical polymerizable compound (A2), an allyl compound, a vinyl compound, a methacrylate compound, an acrylate compound, and an acenaphthylene compound, and the like can be listed.

[0090] The allyl compound is a compound having an allyl group in a molecule. As the allyl compound, a triallyl isocyanurate compound such as triallyl isocyanurate (TAIC), a diallyl bisphenol compound, and a diallyl phthalate (DAP) can be exemplified.

[0091] The vinyl compound is a compound having a vinyl group in a molecule. As the vinyl compound, a monofunctional vinyl compound (monovinyl compound) having one vinyl group in a molecule, and a polyfunctional vinyl compound having two or more vinyl groups in a molecule can be exemplified. As the monofunctional vinyl compound, a styrene compound can be exemplified. As the polyfunctional vinyl compound, a polyfunctional aromatic vinyl compound, and a vinyl hydrocarbon compound can be exemplified. Further, as the polyfunctional aromatic vinyl compound, divinylbenzene can be exemplified. Further, as the vinyl hydrocarbon compound, a polybutadiene compound can be exemplified.

[0092] The methacrylate compound is a compound having a methacryl group in a molecule. As the methacrylate compound, a monofunctional methacrylate compound having one methacryl group in a molecule, and a polyfunctional methacrylate compound having two or more methacryl groups in a molecule can be exemplified. As the monofunctional methacrylate compound, a methacrylate compound such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate can be exemplified. As the polyfunctional methacrylate compound, a dimethacrylate compound such as tricyclodecane dimethanol dimethacrylate (DCP) can be exemplified.

[0093] The acrylate compound is a compound having an acryl group in a molecule. As the acrylate compound, a monofunctional acrylate compound having one acryl group in a molecule, and a polyfunctional acrylate compound having two or more acryl groups in a molecule can be exemplified. As the monofunctional acrylate compound, a methacrylate compound such as methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate can be exemplified. As the polyfunctional acrylate compound, a diacrylate compound such as tricyclodecane dimethanol diacrylate can be exemplified.

[0094] The acenaphthylene compound is a compound having an acenaphthylene structure in the molecule. As the acenaphthylene compound, for example, acenaphthylene, alkyl acenaphthylenes, halogenated acenaphthylenes, and phenyl acenaphthylenes, etc. can be exemplified. As the alkyl acenaphthylenes, for example, 1-methyl acenaphthylene, 3-methyl acenaphthylene, 4-methyl acenaphthylene, 5-methyl acenaphthylene, 1-ethyl acenaphthylene, 3-ethyl acenaphthylene, 4-ethyl acenaphthylene, 5-ethyl acenaphthylene, etc. can be exemplified. As the halogenated acenaphthylenes, for example, 1-chloro acenaphthylene, 3-chloro acenaphthylene, 4-chloro acenaphthylene, 5-chloro acenaphthylene, 1-bromo acenaphthylene, 3-bromo acenaphthylene, 4-bromo acenaphthylene, 5-bromo acenaphthylene, etc. can be exemplified. As the phenyl acenaphthylenes, for example, 1-phenyl acenaphthylene, 3-phenyl acenaphthylene, 4-phenyl acenaphthylene, 5-phenyl acenaphthylene, etc. can be exemplified. As the acenaphthylene compound, it can be a monofunctional acenaphthylene compound having one acenaphthylene structure in the molecule as described above, or it can be a multifunctional acenaphthylene compound having two or more acenaphthylene structures in the molecule.

[0095] In the present embodiment, as the other radical polymerizable compound (A2), among the radical polymerizable compounds described above, an allyl compound, a multifunctional aromatic vinyl compound, a multifunctional methacrylate compound, a multifunctional acrylate compound, a polybutadiene compound, an acenaphthylene compound, a styrene compound, and the like are preferably used.

[0096] The radical polymerizable compound (A) can be formed from the polyphenylene ether compound (Al), or from the radical polymerizable compound (other radical polymerizable compound) (A2) other than the polyphenylene ether compound (Al). In a preferred embodiment, the radical polymerizable compound (A) preferably contains the radical polymerizable compound (Al) as described above, and more preferably contains the polyphenylene ether compound (Al) and the other radical polymerizable compound (A2). In addition, the other radical polymerizable compound (A2) can be used alone, or two or more kinds thereof can be used in combination.

[0097] The content of the radical polymerizable compound (A) in the resin composition of the present embodiment is preferably about 50 to 100% by mass, and further preferably about 60 to 80% by mass, relative to the total amount of the resin component (organic resin component in the resin composition) in the resin composition. It is considered that by this, a cured product having low dielectric properties can be more reliably obtained.

[0098] Further, in the case where the radical polymerizable compound (A) contains the radical polymerizable compound (Al) and the radical polymerizable compound (A2), the ratio of their contents (Al):(A2) is about 95:5 to 50:50 in terms of mass ratio.

[0099] (Other thermosetting resins and curing agents)

[0100] The resin component of the resin composition of the present embodiment can further contain other thermosetting resins in addition to the radical polymerizable compound (A) described above.

[0101] As the thermosetting resin used in the present embodiment, for example, an epoxy compound, a polyphenylene ether compound, a cyanate ester compound, a phenol compound, a benzoxazine compound, an active ester compound, or the like can be exemplified. Among them, from the viewpoint of curability and moldability, it is preferable to use a benzoxazine compound or the like.

[0102] The benzoxazine compound can be used as a commercially available product, and for example, P-d, F-a, ALP-d, or the like manufactured by Shikoku Chemicals Corporation can be exemplified.

[0103] In the case where the resin composition of the present embodiment contains not only the radical polymerizable compound (A) but also the thermosetting resin, the content ratio of them, that is, the ratio of the radical polymerizable compound (A) : the thermosetting resin is about 95 : 5 to 50 : 50 in terms of mass ratio.

[0104] (Inorganic Filler)

[0105] The resin composition related to the present embodiment contains a boron nitride filler (B) as an inorganic filler. Furthermore, the boron nitride filler (B) contains 10 to 50% by mass of agglomerated boron nitride filler (bl) relative to the total amount of the boron nitride filler (B). The agglomerated boron nitride filler (bl) can impart higher thermal conductivity to the resin composition than the flaky boron used in the past, and thus the addition amount of the boron nitride filler (B) can be reduced. Therefore, a resin composition that ensures moldability and has higher thermal conductivity can be obtained. The preferable content of the agglomerated boron nitride filler (bl) relative to the total amount of the boron nitride filler (B) is 10 to 50% by mass, and further preferably 10 to 25% by mass.

[0106] • Agglomerated boron nitride filler (bl)

[0107] The agglomerated boron nitride filler (bl) in the present embodiment is a boron nitride agglomerated particle obtained by agglomerating boron nitride particles as primary particles. The boron nitride of the primary particles is not particularly limited, and for example, hexagonal system normal pressure phase (h-BN) and cubic system high pressure phase (c-BN) used as general inorganic fillers, or the like can be exemplified. The method of obtaining the agglomerated particle is not particularly limited, and for example, the primary particles of boron nitride can be granulated into a spherical shape by using a component as an organic binder, and then calcined at high temperature, pulverized, fractionated, thereby becoming the agglomerated boron nitride filler (bl).

[0108] Note that in the present specification, agglomeration of the boron filler does not refer to a state in which particles are agglomerated together based on inter-particle interactions, but refers to a state in which boron nitride particles as primary particles are agglomerated to form secondary particles by using an organic binder. That is, the agglomerated boron nitride filler (b1) contains boron nitride particles as primary particles, which are agglomerated to form secondary particles by using an organic binder. The method for obtaining the agglomerated boron nitride filler (b1) such as this is not particularly limited, and for example, the boron nitride primary particles can be granulated into a spherical shape by using a component as an organic binder, and then calcination, pulverization, and classification can be performed at a high temperature to obtain the agglomerated boron nitride filler.

[0109] Preferably, the particle size distribution of the agglomerated boron nitride filler (b1) has a cumulative value 50% particle size (D50) of 3.0 to 25.0 μm, and a cumulative value 90% particle size (D90) of 50.0 μm or less. It is believed that the above effects based on the agglomerated boron nitride filler (b1) can be more reliably obtained. It is believed that if the particle sizes (D50, D90) are within the above ranges, the viscosity of the varnish and the resin composition is inhibited from rising, and the moldability is more favorable. A more preferable range of the particle size (D50) is 4 to 20 μm, and a more preferable range of the particle size (D90) is 10 to 35 μm.

[0110] In the present specification, the particle size distribution is a value measured by particle size distribution measurement using a laser diffraction and scattering method, and can be measured using, for example, a laser diffraction / scattering type particle size distribution measuring device "LA-960V2" (manufactured by HORIBA, Ltd.) or the like used in the Examples described later.

[0111] Further, the specific surface area of the agglomerated boron nitride filler (b1) is preferably 0.5 to 15 m 2 / g or so. It is believed that, in this case, the adhesion properties such as the peel strength are more favorable, the viscosity of the varnish and the resin composition is inhibited from rising, and thus the moldability is also favorable. A more preferable range of the specific surface area is 0.5 to 10 m 2 / g or so.

[0112] • Flaky boron nitride filler (b2)

[0113] The boron nitride filler (B) of the present embodiment contains 50 to 90 mass% of boron nitride other than the agglomerated boron nitride filler (bl) with respect to the total amount of the boron nitride filler (B). As the boron nitride other than the agglomerated boron nitride filler (bl), there is no particular limitation, and it is preferable to contain a non-agglomerated flaky boron nitride filler (b2). Thereby, there are advantages that the viscosity of the varnish and the resin composition is reduced and the flowability is improved. In the present specification, the state that the filler is not agglomerated means a state that does not contain an organic binder and does not form secondary particles. That is, the non-agglomerated flaky boron nitride filler (b2) means flaky boron nitride that does not contain an organic binder and does not form secondary particles.

[0114] Preferably, the particle size (D50) at the cumulative value of 50% in the particle size distribution of the flaky boron nitride filler (b2) is 3.0 to 25.0 μm, and the particle size (D90) at the cumulative value of 90% in the particle size distribution is 70.0 μm or less. It is considered that thereby the above-described effects based on the flaky boron nitride filler (b2) can be more reliably obtained. A more preferable range of the particle size (D50) is 4 to 20 μm, and a more preferable range of the particle size (D90) is 5 to 45 μm.

[0115] Further, the specific surface area of the flaky boron nitride filler (b2) is preferably 0.5 to 15 m 2 / g or so, and more preferably 0.5 to 10 m 2 / g or so.

[0116] The content of the flaky boron nitride filler (b2) with respect to the total amount of the boron nitride filler (B) is preferably 50 to 90 mass%, and more preferably 80 to 90 mass%. That is, the boron nitride filler (B) of the present embodiment can contain the agglomerated boron nitride filler (bl) and the flaky boron nitride filler (b2), and can contain boron nitride other than these.

[0117] In the resin composition of the present embodiment, the content of the entire boron nitride filler (B) with respect to 100 mass parts of the resin component is preferably 80 to 250 mass parts. It is considered that thereby high thermal conductivity can be more reliably obtained. A more preferable range of the content is 80 to 150 mass parts.

[0118] • Silica filler (C)

[0119] The resin composition of the present embodiment preferably further contains a silica filler (C) as an inorganic filler other than the boron nitride filler (B). By containing the silica filler (C), there are advantages that the filling amount of the inorganic filler can be increased and the coefficient of thermal expansion (CTE) can be reduced.

[0120] The silica filler (C) used in the present embodiment is not particularly limited as long as it can be used as an inorganic filler. The silica of the present embodiment can be a silica subjected to surface treatment or a silica not subjected to surface treatment. Further, as the surface treatment, for example, treatment with a silane coupling agent or the like can be exemplified.

[0121] As the silane coupling agent, 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, or the like can be exemplified. That is, as the silane coupling agent, 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 having a hydrolyzable group such as a methoxy group or an ethoxy group, or the like can be exemplified.

[0122] As the silane coupling agent having a vinyl group, for example, vinyltriethoxysilane, vinyltrimethoxysilane, or the like can be exemplified. As the silane coupling agent having a styryl group, for example, p-styryltrimethoxysilane, p-styryltriethoxysilane, or the like can be exemplified. As the silane coupling agent having a methacryl group, for example, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylethyldiethoxysilane, or the like can be exemplified. As the silane coupling agent having an acryl group, for example, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, or the like can be exemplified. As the silane coupling agent having an anilino group, for example, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, or the like can be exemplified.

[0123] It is preferable that the particle size (D50) at the cumulative value of 50% in the particle size distribution of the silica filler (C) be 0.5 to 10.0 μm and the particle size (D90) at the cumulative value of 90% in the particle size distribution be 50.0 μm or less. It is considered that the above effects based on the silica filler (C) can be more reliably obtained thereby. A more preferable range of the particle size (D50) is 1 to 6 μm, and a more preferable range of the particle size (D90) is 5 to 45 μm.

[0124] Further, the specific surface area of the silica filler (C) is preferably around 0.5 to 15 m 2 / g, and more preferably around 0.5 to 10 m 2 / g.

[0125] The content of the silica filler (C) is preferably 50 to 150 parts by mass, more preferably 75 to 125 parts by mass, relative to 100 parts by mass of the resin component.

[0126] The resin composition of the present embodiment can also contain an inorganic filler other than the boron nitride filler (B) and the silica filler (C). As the inorganic filler other than the boron nitride filler and the silica filler, there is no particular limitation as long as it can be used as an inorganic filler contained in the resin composition. Specifically, for example, metal oxide fillers (alumina fillers, titania fillers, magnesium oxide fillers, and mica fillers, etc.), metal hydroxide fillers (aluminum hydroxide fillers and magnesium hydroxide fillers, etc.), talc fillers, aluminum borate fillers, barium sulfate fillers, aluminum nitride fillers, silicon nitride fillers, magnesium carbonate fillers (anhydrous magnesium carbonate fillers, etc.), and calcium carbonate fillers, etc. can be listed. Among them, anhydrous magnesium carbonate fillers, alumina fillers, and silicon nitride fillers, etc. are preferable.

[0127] The inorganic filler other than the boron nitride filler and the silica filler can be an inorganic filler subjected to surface treatment, or an inorganic filler not subjected to surface treatment. Further, as the surface treatment, for example, treatment with a silane coupling agent, etc. can be listed.

[0128] Further, the total content of the inorganic fillers in the resin composition of the present embodiment is preferably 50 to 400 parts by mass, more preferably 800 to 250 parts by mass, relative to 100 parts by mass of the solid component of the resin composition of the present embodiment. Here, the solid component of the resin composition refers to the solid component of the resin remaining after removing volatile components such as solvents from the resin composition.

[0129] (Fire Retardant (D))

[0130] The resin composition of the present embodiment preferably further contains a fire retardant (D). Thereby, the flame retardancy can also be improved.

[0131] As the fire retardant (D), there is no particular limitation, and for example, halogen-containing fire retardants such as polybrominated biphenyl, polybrominated diphenyl ether, hexabromocyclododecane, tetrabromobisphenol A, 2,4,6-tribromophenol, etc.; phosphorus (P) fire retardants such as phosphate ester compounds, phosphazene compounds, phosphate ester amide compounds, HCA derivatives, red phosphorus, dialkyl phosphinic acid salts, etc. can be listed.

[0132] The flame retardant (D) used in the present embodiment can be a compatible flame retardant compatible with the radical polymerizable compound (A), or can be an incompatible flame retardant incompatible with the radical polymerizable compound (A). Here, compatibility means a state of being finely dispersed at a molecular level in the radical polymerizable compound (A), for example. Further, incompatibility means a state of being dispersed in the form of islands in the mixture, with the object (phosphorus compound) being incompatible in the radical polymerizable compound (A).

[0133] In the case where the resin composition of the present embodiment contains the flame retardant (D), the content of the flame retardant (D) is preferably about 5 to 100 parts by mass, and more preferably about 5 to 50 parts by mass, with respect to 100 parts by mass of the radical polymerizable compound (A).

[0134] (Reaction initiator)

[0135] The resin composition of the present embodiment can also contain a reaction initiator. The resin composition can undergo a radical polymerization (curing) reaction even if it does not contain a reaction initiator. However, depending on the process conditions, it can sometimes be difficult to raise the temperature up to the point where curing proceeds, and thus a reaction initiator can also be added.

[0136] The reaction initiator is not particularly limited as long as it can promote the curing reaction of the resin composition. Specifically, examples include metal oxides, azo compounds, peroxides, and the like, and more preferably at least one of a peroxide and an azo compound.

[0137] As the metal oxide, specifically, a carboxylic acid metal salt or the like can be exemplified.

[0138] As the organic peroxide, α,α’-di(tert-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)-3-hexyne, benzoyl peroxide, 3,3’,5,5’-tetramethyl-1,4-benzenediol benzenequinone, chloranil, 2,4,6-tri-tert-butylphenoxy, tert-butylperoxy isopropyl monocarbonate, azobisisobutyronitrile, and the like can be exemplified.

[0139] As the azo compound, specifically, 2,2’-azobis(2,4,4-trimethylpentane), 2,2’-azobis(N-butyl-2-methylpropionamide), 2,2’-azobis(2-methylbutyronitrile), and the like can be exemplified.

[0140] Among them, preferred reaction initiators are 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(N-butyl-2-methylpropionamide), and the like. These reaction initiators have little influence on dielectric properties. Furthermore, since the reaction initiation temperature is relatively high, it is possible to suppress the promotion of the curing reaction at the time of drying of the prepreg and the like, when curing is not required, and it is possible to suppress the decrease in the storage properties of the resin composition.

[0141] The reaction initiator described above can be used alone or in combination of two or more.

[0142] In the case where the resin composition of the present embodiment contains the reaction initiator, the content thereof is not particularly limited, and, for example, it is preferably 0.1 to 5.0 parts by mass, more preferably 0.5 to 3.0 parts by mass, and further preferably 0.5 to 2.0 parts by mass, relative to 100 parts by mass of the radically polymerizable compound (A).

[0143] (Other elastomers)

[0144] In addition, in order to more reliably ensure low dielectric properties and adhesion strength and the like, in the resin composition of the present embodiment, as a resin component, in addition to the radically polymerizable compound (A) described above, a thermoplastic resin that does not have an unsaturated group can also be added.

[0145] As the thermoplastic resin, for example, a thermoplastic polyphenylene ether resin, a polyphenylene sulfide resin, a liquid crystal polymer, a polyethylene resin, a polystyrene resin, a polyurethane resin, a polypropylene resin, an ABS resin, an acrylic resin, a polyethylene terephthalate resin, a polycarbonate resin, a polyacetal resin, a polyimide resin, a polyamide-imide resin, a polytetrafluoroethylene resin, a cyclic olefin polymer, a cyclic olefin copolymer, a styrene-based elastomer, and the like can be exemplified. The above-described resins can be used alone or in combination of two or more.

[0146] Among them, the styrene-based elastomer is a polymer obtained by polymerizing a monomer containing a styrene-based monomer, and can be a styrene-based copolymer. Furthermore, as the styrene-based copolymer, for example, a copolymer obtained by copolymerizing one or more of the above-described styrene-based monomers and one or more of other monomers copolymerizable with the styrene-based monomers, and the like can be exemplified. The styrene-based copolymer can be a random copolymer or a block copolymer as long as it has a structure derived from the styrene-based monomer in the molecule. As the block copolymer, a binary copolymer derived from a structure (repeating unit) of the styrene-based monomer and a structure (repeating unit) of the other copolymerizable monomer, and a ternary copolymer derived from a structure (repeating unit) of the styrene-based monomer, a structure (repeating unit) of the other copolymerizable monomer, and a structure (repeating unit) of the styrene-based monomer, and the like can be exemplified.

[0147] The styrenic elastomer can also be a hydrogenated styrenic copolymer obtained by hydrogenating the styrenic copolymer.

[0148] The styrenic elastomer can be used alone with one styrenic polymer or in combination with two or more styrenic polymers.

[0149] The styrenic elastomer can also be an anhydride-modified styrenic elastomer obtained by modifying a part of the molecule with an anhydride.

[0150] The weight average molecular weight of the styrenic elastomer is preferably 3,500 to 300,000, and more preferably 3,500 to 200,000. If the molecular weight is too low, there is a tendency for the glass transition temperature of the cured product of the resin composition to decrease or for the heat resistance to decrease. In addition, if the molecular weight is too high, there is a tendency for the viscosity when the resin composition is made into a varnish or for the viscosity of the resin composition when heat formed to become too high. Note that the weight average molecular weight is a value obtained by measuring with a usual molecular weight measuring method, and specifically, a value measured using gel permeation chromatography (GPC) or the like can be cited.

[0151] As the styrenic elastomer, commercially available products can be used, and for example, SEPTON (registered trademark) and HYBRAR (registered trademark) manufactured by Kuraray Co., Ltd., MILASTOMER (registered trademark) manufactured by Mitsui Chemicals, Inc., Tuftec (registered trademark) and Tufprene (registered trademark) manufactured by Asahi Kasei Corporation, DYNARON (registered trademark) manufactured by JSR Corporation, and SIBSTAR (registered trademark) manufactured by Tokiwa Chemical Industry Co., Ltd. can be used.

[0152] In the case where the resin composition of the present embodiment contains a thermoplastic resin having no unsaturated group, the content thereof is preferably about 0.1 to 30 parts by mass and more preferably about 1 to 15 parts by mass, relative to 100 parts by mass of the total of the radically polymerizable compound (A) and the thermoplastic resin.

[0153] (Other components)

[0154] The resin composition according to the present embodiment can further contain, as needed, components other than the above-described components (other components) without impairing the effects of the present application. As the other components contained in the resin composition according to the present embodiment, additives such as a silane coupling agent, an antifoaming agent, an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a dye or a pigment, a dispersant, and a lubricant can be further contained.

[0155] (Method for producing)

[0156] As a method of producing the resin composition, there is no particular limitation, and for example, a method in which a resin component containing a radical polymerizable compound (A) is mixed, and then an inorganic filler is added, and the like can be exemplified. Specifically, in the case where a varnish-like composition containing an organic solvent is obtained, a method described in the following description of a prepreg, and the like can be exemplified.

[0157] Further, by using the resin composition according to the present embodiment, a prepreg, a metal-clad laminate, a wiring board, a resin-coated metal foil, and a resin-coated film can be obtained as described below. In the following description, each symbol represents the following: 1 prepreg, 2 resin composition or semi-cured product of the resin composition, 3 fibrous base material, 11 metal-clad laminate, 12 insulating 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.

[0158] [Prepreg]

[0159] Figure 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to the present embodiment.

[0160] As shown in Figure 1 , the prepreg 1 according to the present embodiment includes: the resin composition or the semi-cured product of the resin composition 2; and the fibrous base material 3. The prepreg 1 includes: the resin composition or the semi-cured product of the resin composition 2; and the fibrous base material 3 present in the resin composition or the semi-cured product of the resin composition 2.

[0161] Note that, in the present embodiment, a semi-cured product is a substance in a state in which a resin composition is cured to an intermediate stage to a degree that further curing is possible. That is, a semi-cured product is a substance in a state in which a resin composition is semi-cured (B-stage). For example, if a resin composition is heated, the viscosity initially gradually decreases, and then starts to cure, and the viscosity gradually increases. In this case, as a semi-cured state, a state during a period from the start of the increase in viscosity to before the completion of curing, and the like can be exemplified.

[0162] Further, as a prepreg obtained using the resin composition according to the present embodiment, as described above, it can be a prepreg including a semi-cured product of the resin composition, and further, it can be a prepreg including an uncured resin composition. That is, it can be a prepreg including a semi-cured product of the resin composition (B-stage resin composition) and a fibrous base material, and it can be a prepreg including a resin composition before curing (A-stage resin composition) and a fibrous base material. Further, as the resin composition or the semi-cured product of the resin composition, it can be a substance obtained by drying or heat-drying the resin composition.

[0163] In the production of the prepreg, the resin composition 2 is mostly used as a varnish in order to impregnate into the fibrous base material 3 which is a base material for forming the prepreg. That is, the resin composition 2 is mostly a resin varnish which is prepared as a varnish. The resin composition (resin varnish) as a varnish can be prepared, for example, in the following manner.

[0164] First, each component in the composition of the resin composition which is soluble in an organic solvent is put into the organic solvent and dissolved. At this time, heating can be performed as necessary. Then, a component (for example, inorganic filler, etc.) which is not soluble in the organic solvent is added as necessary, and is dispersed to a specified dispersion state using a disperser or the like, whereby a resin composition as a varnish can be prepared. As the organic solvent used here, there is no particular limitation as long as it is an organic solvent which can dissolve the radical polymerizable compound or the like and does not hinder the curing reaction. Specifically, for example, toluene, methyl ethyl ketone (MEK), etc. can be mentioned.

[0165] The method for producing the prepreg is not particularly limited as long as the prepreg can be produced. Specifically, in the production of the prepreg, the resin composition used in the present embodiment described above is mostly used as a resin varnish as a varnish as described above.

[0166] As the fibrous base material, specifically, for example, glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and cotton flannel paper can be mentioned. Note that if glass cloth is used, a laminate having excellent mechanical strength can be obtained, and a glass cloth which has been subjected to a flat processing is particularly preferred. As the flat processing, specifically, for example, a method in which a glass cloth is continuously pressed with a press roller at an appropriate pressure to compress the yarn into a flat shape can be mentioned. Note that the thickness of the fibrous base material which is generally used is, for example, 0.01 mm or more and 0.3 mm or less.

[0167] The method for producing the prepreg is not particularly limited as long as the prepreg can be produced. Specifically, in the production of the prepreg, the resin composition involved in the present embodiment described above is mostly used as a resin varnish as a varnish as described above.

[0168] As the method for producing the prepreg 1, for example, a method in which the resin composition 2 (for example, the resin composition 2 which has been prepared as a varnish) is impregnated into the fibrous base material 3 and then dried can be mentioned. The impregnation of the resin composition 2 into the fibrous base material 3 is performed by dipping, coating, or the like. The impregnation can be performed repeatedly as many times as necessary. Also at this time, the impregnation can be performed repeatedly using a plurality of resin compositions having different compositions or concentrations to adjust the final desired composition and the impregnation amount.

[0169] The fibrous base material 3 impregnated with the resin composition (resin varnish) 2 is heated under a desired heating condition (for example, heating at 80°C or higher and 180°C or lower for 1 minute or longer and 10 minutes or shorter). By the heating, a prepreg 1 in a pre-cured (A-stage) or semi-cured state (B-stage) can be obtained. Note that by the heating, the organic solvent can be volatilized from the resin varnish, and the organic solvent can be reduced or removed.

[0170] [Metallized foil laminate]

[0171] Figure 2 is a schematic cross-sectional view showing an example of a metallized foil laminate 11 to which an embodiment of the present application is applied.

[0172] As shown in Figure 2 , the metallized foil laminate 11 includes: an insulating layer 12 including a cured product of the prepreg 1 shown in Figure 1 ; and a metal foil 13 laminated together with the insulating layer 12. That is, the metallized foil laminate 11 includes: the insulating layer 12 including a cured product of a resin composition; and the metal foil 13 provided on the insulating layer 12. Further, the insulating layer 12 can be formed of a cured product of the resin composition, or can be formed of a cured product of the prepreg. Further, the thickness of the metal foil 13 is not particularly limited depending on the performance and the like required for a wiring board to be finally obtained. The thickness of the metal foil 13 can be appropriately set depending on the intended purpose, and for example, is preferably 0.2 to 70 μm. Further, as the metal foil 13, for example, a copper foil, an aluminum foil, and the like can be exemplified, and in the case where the metal foil is thin, in order to improve handleability, it can be a carrier-equipped copper foil provided with a release layer and a carrier.

[0173] As a 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 manufacturing the metal-clad laminate 11 using the prepreg 1 can be exemplified. As the method, a method of taking one prepreg 1 or overlapping a plurality of prepregs 1, further overlapping a metal foil 13 such as a copper foil on both surfaces or one surface thereof, and integrally laminating the metal foil 13 and the prepreg 1 by heat and pressure molding, thereby manufacturing a laminate 11 of a both-surface metal-clad or one-surface metal-clad, and the like can be exemplified. That is, the metal-clad laminate 11 is obtained by laminating the metal foil 13 on the prepreg 1 and performing heat and pressure molding. Further, the heat and pressure molding conditions can be appropriately set according to the thickness of the metal-clad laminate 11 to be manufactured or the kind of the composition of the prepreg 1, and the like. For example, the temperature can be set to 170 to 230°C, the pressure can be set to 3 to 5 MPa, and the time can be set to 60 to 150 minutes. Further, the metal-clad laminate can also be manufactured without using the prepreg. For example, a method of applying a varnish-like resin composition to a metal foil, forming a layer containing the resin composition on the metal foil, and then performing heat and pressure molding, and the like can be exemplified.

[0174] [Wire board]

[0175] Figure 3 is a schematic cross-sectional view showing an example of a wire board 21 to which the embodiment of the present application is applied.

[0176] As Figure 3 shown, the wire board 21 to which the embodiment of the present application is applied is provided with: an insulating layer 12 which is used by curing the prepreg 1 shown in Figure 1 ; and a wire 14 which is formed by laminating the insulating layer 12 together and removing a part of the metal foil 13. That is, the wire board 21 is provided with: the insulating layer 12 which contains a cured product of a resin composition; and the wire 14 which is provided on the insulating layer 12. Further, the insulating layer 12 can be formed of a cured product of the resin composition, or can be formed of a cured product of the prepreg.

[0177] The method of manufacturing the wiring board 21 is not particularly limited as long as the wiring board 21 can be manufactured. Specifically, a method of using the prepreg 1 to produce the wiring board 21, and the like can be cited. As the method, a method of forming a wiring by etching processing or the like of the metal foil 13 on the surface of the metal-clad laminate sheet 11 produced as described above, thereby producing the wiring board 21 in which the wiring is provided on the surface of the insulating layer 12 as an electric circuit, and the like can be cited. That is, for the wiring board 21, a portion of the metal foil 13 on the surface of the metal-clad laminate sheet 11 can be removed, thereby forming the electric circuit to be obtained. Further, as the method of forming the electric circuit, in addition to the above-described method, a method of forming the electric circuit by a semi-additive process (SAP) or a modified semi-additive process (MSAP), and the like can be cited.

[0178] [metal foil with resin]

[0179] Figure 4 is a schematic cross-sectional view showing an example of the metal foil with resin 31 to which the present embodiment is directed.

[0180] As shown in Figure 4 , the metal foil with resin 31 to which the present embodiment is directed includes a resin layer 32 including the resin composition or a semi-cured product of the resin composition, and a metal foil 13. The metal foil with resin 31 has the metal foil 13 on the surface of the resin layer 32. That is, the metal foil with resin 31 includes the resin layer 32, and the metal foil 13 laminated with the resin layer 32. Further, the metal foil with resin 31 can include other layers between the resin layer 32 and the metal foil 13.

[0181] Further, as the resin layer 32, a semi-cured product of the resin composition as described above can be included, and a non-cured resin composition can also be included. That is, the metal foil with resin 31 can be a metal foil with resin including a resin layer including a semi-cured product of the resin composition (a B-stage resin composition), and a metal foil, and can also be a metal foil with resin including a resin layer including a non-cured resin composition (an A-stage resin composition), and a metal foil. Further, as the resin layer, as long as the resin layer includes the resin composition or a semi-cured product of the resin composition, a fibrous base material can be included or not included. Further, as the resin composition or the semi-cured product of the resin composition, a substance obtained by drying or heat-drying the resin composition can be used. Further, as the fibrous base material, the same material as the fibrous base material of the prepreg can be used.

[0182] Further, as the metal foil, a metal foil used in a metal-clad laminate can be used without any limitation. As the metal foil, for example, a copper foil, an aluminum foil, and the like can be exemplified.

[0183] The resin-coated metal foil 31 and the resin-coated film 41 can be provided with a cover film as needed. By providing a cover film, the mixing of foreign matter and the like can be prevented. As the cover film, there is no particular limitation, and for example, a polyolefin film, a polyester film, a polymethylpentene film, and a film formed by providing a release agent layer on these films can be exemplified.

[0184] The method of manufacturing the resin-coated metal foil 31 is not particularly limited as long as the resin-coated metal foil 31 can be manufactured. As the method of manufacturing the resin-coated metal foil 31, for example, a method of applying the above-mentioned varnish-like resin composition (resin varnish) to the metal foil 13 and performing heating can be exemplified. For example, the varnish-like resin composition is applied to the metal foil 13 by using a bar coater. The applied resin composition is heated, for example, under conditions of 80°C or higher and 180°C or lower, for 1 minute or longer and 10 minutes or shorter. The heated resin composition is formed as an uncured resin layer 32 on the metal foil 13. Note that, by the heating, the organic solvent is volatilized from the resin varnish, and the organic solvent can be reduced or removed.

[0185] [Resin-coated film]

[0186] Figure 5 is a schematic cross-sectional view showing an example of the resin-coated film 41 to which the present embodiment is applied.

[0187] As shown in Figure 5 , the resin-coated film 41 to which the present embodiment is applied is provided with: a resin layer 42 including the resin composition or a semi-cured product of the resin composition; and a support film 43. The resin-coated film 41 is provided with: the resin layer 42; and the support film 43 laminated together with the resin layer 42. Further, the resin-coated film 41 can further be provided with other layers between the resin layer 42 and the support film 43.

[0188] Further, as the resin layer 42, a prepreg of the resin composition as described above can be included, and further, the uncured resin composition can be included. That is, the resin-coated film 41 can be a resin-coated film provided with a resin layer including a prepreg of the resin composition (the resin composition in the B-stage) and a support film, or can be a resin-coated film provided with a resin layer including the resin composition before curing (the resin composition in the A-stage) and a support film. Further, as the resin layer, it is only necessary to include the resin composition or the prepreg of the resin composition, and a fibrous base material can be included or not included. Further, as the resin composition or the prepreg of the resin composition, it can be a substance obtained by drying or heat-drying the resin composition. Further, as the fibrous base material, the same material as the fibrous base material of the prepreg can be used.

[0189] Further, as the support film 43, a support film used in a resin-coated film can be used without limitation. As the support film, an electrically insulating film such as a polyester film, a polyethylene terephthalate (PET) film, a polyimide film, a polyoxadiazole film, a polyether ether ketone film, a polyphenylene sulfide film, a polyamide film, a polycarbonate film, a polyarylate film, and the like can be exemplified.

[0190] The resin-coated film 41 can be provided with a cover film or the like as necessary. By being provided with a cover film, the mixing-in of foreign matter or the like can be prevented. As the cover film, there is no particular limitation, and a polyolefin film, a polyester film, a polymethylpentene film, and the like can be exemplified.

[0191] As the support film and the cover film, a film subjected to surface treatment such as mat treatment, corona treatment, mold release treatment, and roughening treatment as necessary can be used.

[0192] The method of manufacturing the resin-coated film 41 is not particularly limited as long as the resin-coated film 41 can be manufactured. The method of manufacturing the resin-coated film 41 can include, for example, a method of applying a varnish-like resin composition (resin varnish) described above to a support film 43 and performing heating. For example, the varnish-like resin composition is applied to the support film 43 by using a bar coater. The applied resin composition is heated, for example, under conditions of 80°C or higher and 180°C or lower for 1 minute or longer and 10 minutes or less. The heated resin composition is formed as the uncured resin layer 42 on the support film 43. Note that, by the heating, the organic solvent is volatilized from the resin varnish, and the organic solvent can be reduced or removed.

[0193] The prepreg, resin-coated film, and resin-coated metal foil obtained using the resin composition of the present embodiment are very useful in industrial applications because the cured product thereof has excellent low dielectric properties and high thermal conductivity and also has excellent moldability. Furthermore, the metal-clad laminate and wiring board having an insulating layer containing the cured product of the resin composition of the present embodiment have the advantages of having low dielectric properties and high thermal conductivity and also having excellent processability.

[0194] The present specification discloses the technology of the various embodiments as described above, and the main technology thereof is summarized as follows.

[0195] The resin composition of the first aspect of the present invention contains: a resin component containing a radical polymerizable compound (A); and a boron nitride filler (B), wherein the boron nitride filler (B) contains 10 to 50 mass% of agglomerated boron nitride filler (b1) with respect to the total amount of the boron nitride filler (B), the thermal conductivity of the cured product is 1.0 W / mK or more, and the relative dielectric constant of the cured product is 4.0 or less.

[0196] The resin composition of the second aspect of the present invention is: in the resin composition of the first aspect, the content of the boron nitride filler (B) is 80 to 250 parts by mass with respect to 100 parts by mass of the resin component.

[0197] The resin composition of the third aspect of the present invention is: in the resin composition of the first or second aspect, in the particle size distribution of the agglomerated boron nitride filler (b1), the particle size at the cumulative value of 50% (D50) is 3.0 to 25.0 μm, and the particle size at the cumulative value of 90% (D90) is 50.0 μm or less.

[0198] The resin composition of the fourth aspect of the present invention is: in the resin composition of any one of the first to third aspects, the boron nitride filler (B) contains unagglomerated flaky boron nitride filler (b2).

[0199] The resin composition of the fifth aspect of the present invention is: in the resin composition of the fourth aspect, the content of the flaky boron nitride filler (b2) is 50 to 90 mass% with respect to the total amount of the boron nitride filler (B).

[0200] The resin composition of the sixth aspect of the present invention is: in the resin composition of the fourth or fifth aspect, in the particle size distribution of the flaky boron nitride filler (b2), the particle size at the cumulative value of 50% (D50) is 3.0 to 25.0 μm, and the particle size at the cumulative value of 90% (D90) is 70.0 μm or less.

[0201] The resin composition according to the seventh aspect of the present application is the resin composition according to any one of the first to sixth aspects, further containing a silica filler (C) in an amount of 50 to 150 parts by mass with respect to 100 parts by mass of the resin component.

[0202] The resin composition according to the eighth aspect of the present application is the resin composition according to the seventh aspect, wherein the particle size distribution of the silica filler (C) has a cumulative value of 50% of the particle diameter, that is, D50, of 0.5 to 10.0 μm and a cumulative value of 90% of the particle diameter, that is, D90, of 50.0 μm or less.

[0203] The resin composition according to the ninth aspect of the present application is the resin composition according to any one of the first to eighth aspects, wherein the radically polymerizable compound (A) contains 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.

[0204] The resin composition according to the tenth aspect of the present application is the resin composition according to any one of the first to ninth aspects, further containing a flame retardant (D).

[0205] The prepreg according to the eleventh aspect of the present application includes the resin composition according to any one of the first to tenth aspects or a semi-cured product of the resin composition, and a fibrous base material.

[0206] The resin-coated film according to the twelfth aspect of the present application includes a resin layer containing the resin composition according to any one of the first to tenth aspects or a semi-cured product of the resin composition, and a support film.

[0207] The resin-coated metal foil according to the thirteenth aspect of the present application includes a resin layer containing the resin composition according to any one of the first to tenth aspects or a semi-cured product of the resin composition, and a metal foil.

[0208] The metal-clad laminate according to the fourteenth aspect of the present application includes an insulating layer containing a cured product of the resin composition according to any one of the first to tenth aspects or a cured product of the prepreg according to the eleventh aspect, and a metal foil.

[0209] The wiring board according to the fifteenth aspect of the present application includes an insulating layer containing a cured product of the resin composition according to any one of the first to tenth aspects or a cured product of the prepreg according to the eleventh aspect, and a wiring.

[0210] The present application will be further concretely described below by way of examples, but the scope of the present application is not limited by these examples.

[0211] Examples

[0212] [Examples 1 to 16 and Comparative Examples 1 to 8]

[0213] Each component used in the production of the resin composition in the present examples is described.

[0214] [Radical polymerizable compound (A)]

[0215] (Radical polymerizable compound (Al))

[0216] • PPE1: polyphenylene ether compound having a methacryl group at the terminal (SA9000 manufactured by SABIC Innovative Plastics, weight average molecular weight Mw 2000, number of terminal functional groups 2)

[0217] • PPE2: polyphenylene ether compound having a vinylbenzyl (vinylbenzyl) group at the terminal (OPE-2st 1200 manufactured by Mitsubishi Gas Chemical Company, Inc., Mn 1200)

[0218] • Bis-maleimide: bis-maleimide resin (MIR-3000-70MT manufactured by Nippon Shokubai Co., Ltd., molecular weight 1000)

[0219] (Radical polymerizable compound (A2))

[0220] • TAIC: triallyl isocyanurate (TAIC manufactured by Nippon Shokubai Co., Ltd.)

[0221] <Other thermosetting resins>

[0222] • Benzoxazine compound: P-d manufactured by Shikoku Chemicals Corporation

[0223] <Inorganic fillers>

[0224] (Boron nitride filler (B))

[0225] • Flaky boron nitride 1: "SGP" manufactured by Denki Kagaku Co., Ltd.

[0226] • Flaky boron nitride 2: "HGP" manufactured by Denki Kagaku Co., Ltd.

[0227] • Flaky boron nitride 3: "XGP" manufactured by Denki Kagaku Co., Ltd.

[0228] • Agglomerated boron nitride 1: "HP-40J2" manufactured by JFE MINERAL Co., Ltd.

[0229] • Agglomerated boron nitride 2: JFE Mining Corporation "HP-40J11"

[0230] • Agglomerated boron nitride 3: JFE Mining Corporation "HP-40MF100"

[0231] (Silica filler (C))

[0232] • Silica: "FB-7SDC" manufactured by Kanto Chemical Co., Inc.

[0233] (Other inorganic fillers)

[0234] • Alumina (alumina): "DAW-03DC" manufactured by Kanto Chemical Co., Inc.

[0235] (Flame retardant (D))

[0236] • Flame retardant 1: phosphorus-based flame retardant (aromatic condensed phosphate ester compound, manufactured by Otsu Chemical Industry Co., Ltd., PX-200)

[0237] • Flame retardant 2: phosphorus-based flame retardant (phosphinic acid metal salt-based flame retardant, manufactured by Clariant Japan K.K., Exolit OP-935)

[0238] • Flame retardant 3: bromine-based flame retardant (manufactured by Albemarle Jaμan Corporation, SAYTEX 8010)

[0239] <Reaction initiator>

[0240] • Organic peroxide: PBP (1,3-bis(butylperoxyisopropyl)benzene; PERBUTYL P manufactured by NOF Corporation)

[0241] • Azodicarbonamide: oil-soluble azo polymerization initiator (VR-110 manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0242] <Others>

[0243] (Elastomer)

[0244] • Styrene-based polymer 1: styrene-isobutylene-styrene triblock copolymer (manufactured by Tokuyama Corporation, SIBSTAR 103T, weight average molecular weight 90000)

[0245] • Styrene-based polymer 2: hydrogenated methylstyrene (ethylene-methylethylene) methylstyrene copolymer (manufactured by Kuraray Co., Ltd., Septon V9827, weight average molecular weight 92000)

[0246] (Preparation method)

[0247] First, each component except for the inorganic filler was added to an organic solvent in the composition (mass parts, solid content) described in Tables 1 and 2 and mixed. The mixture was stirred for 60 minutes. Then, the filler was added (mass parts) to the obtained liquid, the amount of the organic solvent was adjusted in such a manner that the solid content concentration of the resin composition after dispersion became 65 mass parts, and the filler was dispersed by stirring for 60 minutes, thereby obtaining a varnish-like resin composition (varnish). Note that, as the organic solvent, methyl ethyl ketone (MEK) was used for Examples 9 to 10, and toluene was used other than that.

[0248] Next, the evaluation substrate (cured product of prepreg) was obtained as follows.

[0249] After the obtained varnish was impregnated into a fibrous base material (glass cloth: #1078 type manufactured by Asahi Kasei Corporation, L glass), it was heated and dried at 120°C for 3 minutes, whereby a prepreg was produced. Then, the obtained prepreg was overlapped by 4 pieces and copper foil ("FV-WS" manufactured by Furukawa Electric Co., Ltd., copper foil thickness: 35 μm) was attached to both surfaces thereof, heating was performed at a temperature increasing rate of 4°C / minute to a temperature of 200°C, and heating and pressurization was performed at a temperature of 200°C and a pressure of 3 MPa for 120 minutes, whereby a copper-clad laminate having a board thickness of about 500 μm was produced.

[0250] <Test Example 1>

[0251] In the measurement of thermal conductivity described later, the cured products of three kinds of prepregs having different board thicknesses were used, and in the evaluation test of dielectric properties (relative dielectric constant) and formability, the boards (cured products of prepregs) were used in which the copper foil was removed from the copper-clad laminates in which four pieces of prepreg were overlapped.

[0252] Each evaluation sample produced as described above was evaluated by the following method.

[0253] [Dielectric properties (relative dielectric constant)]

[0254] The relative dielectric constant (Dk) of the evaluation substrate (cured product of prepreg) at 10 GHz was measured by the resonant cavity perturbation method. Specifically, the dielectric loss factor of the evaluation substrate at 10 GHz was measured using a network analyzer (N5230A manufactured by Keysight Technologies). The pass criteria in this example was Dk < 4.0.

[0255] [Formability]

[0256] The appearance and cross-section of the evaluation substrate prepared as described above were observed, and the presence or absence of voids or scratches was confirmed under a scanning electron microscope (S-3000N manufactured by Hitachi High-Technologies Corporation). The absence of voids and scratches was evaluated as "good" (O), and the presence of voids or scratches was evaluated as "not good" (X).

[0257] Further, the viscosity of the obtained varnish was adjusted so that the board thickness became about 400 μm, and a copper-clad laminate was prepared in the same manner as described above, and the same evaluation as described above was performed. The absence of voids and scratches was evaluated as "very good", and the presence of voids or scratches was evaluated as "good".

[0258] The absence of voids and scratches in both conditions (board thickness 500 μm and board thickness 400 μm) was evaluated as "very good", the presence of voids or scratches in the former condition (board thickness 500 μm) was evaluated as "good", and the presence of voids or scratches in both conditions was evaluated as "not good".

[0259] [Thermal conductivity]

[0260] The thermal conductivity of the obtained evaluation substrate (cured product of prepreg) was measured by a method according to ASTM D5470. Specifically, the thermal conductivity of the obtained evaluation substrate was measured using a thermal property evaluation device (T3Ster DynTIM Tester manufactured by Mentor Graphics, Inc.). The pass criteria for the thermal conductivity in the present embodiment was 1.0 W / m-K or more.

[0261] [Particle size distribution of inorganic filler]

[0262] The particle size distribution of the inorganic filler in each of the examples and comparative examples was obtained by measurement using a laser diffraction / scattering type particle size distribution measuring device LA-960V2 (manufactured by Horiba, Ltd.). The specifications of the device were as follows.

[0263] Measurement principle: Mie scattering theory

[0264] Measurement method: flow measurement

[0265] Measurement range: 0.01 μm to 5000 μm

[0266] Light source: LD (650 nm), about 5 mW, LED (405 mm), about 3 mW

[0267] Detector: annular 64-split silicon photodiode x 1, 4-channel array detector x 5, silicon photodetector x 3 Refractive index: 2.250-0.005i

[0268] The specifications of the measuring section (circulatory system) are as follows.

[0269] Dispersion: ultrasonic probe

[0270] Circulation: centrifugal pump

[0271] Agitation: rotating blade

[0272] Flow cell material: synthetic quartz

[0273] The particle size distribution measurement conditions are as follows.

[0274] Each measurement sample was put into a flow cell via a sample cell using toluene as a dispersion solvent, and laser diffraction / scattering type particle size distribution measurement was performed under agitation.

[0275] Regarding the particle size distribution analysis, analysis and calculation were performed using the analysis software "LA-960 Windows version" attached to LA-960 V2. Also, the respective D50 and D90 were calculated.

[0276] [Specific surface area of inorganic filler]

[0277] The specific surface area of each inorganic filler was measured by the BET method using a fully automatic gas adsorption measuring device "autosorb-iQ" (manufactured by Anton Paar Japan).

[0278] The results of the above evaluations are shown in Tables 1 and 2.

[0279]

[0280]

[0281] (Investigation)

[0282] As shown in Table 1, it was confirmed that the examples using the resin composition of the present application can all provide a resin composition capable of obtaining a cured product having low dielectric properties (relative dielectric constant) and high thermal conductivity, and also having moldability. By comparing Examples 3 and 6 with the other examples, it was also confirmed that particularly in the case where agglomerated boron nitride filler (b1) or flaky boron nitride filler (b2) having a specified particle size distribution is used, very excellent moldability can be obtained.

[0283] On the other hand, as shown in Table 2, in Comparative Example 1 regarding a resin composition not containing agglomerated boron nitride filler (b1), sufficient thermal conductivity could not be obtained. Furthermore, in Comparative Examples 2 and 3 where boron nitride was not used as an inorganic filler, the thermal conductivity was poor. In Comparative Example 3, although the thermal conductivity was improved due to the increase in the content of the inorganic filler, low dielectric properties could not be obtained.

[0284] In Comparative Example 4 and Comparative Example 6 in which the content of the agglomerated boron nitride filler (b1) was too low, sufficient thermal conductivity was not obtained, and in Comparative Example 5 in which the content of the agglomerated boron nitride filler (b1) was too high, it was not possible to form an evaluation test sample.

[0285] Further, in Comparative Examples 7 to 8 in which two different flaky boron nitrides were used in combination instead of the agglomerated boron nitride filler (b1), sufficient thermal conductivity was not obtained.

[0286] This application is based on Japanese Patent Application No. 2023-057186 filed on March 31, 2023, the content of which is incorporated herein.

[0287] In order to describe the present application, the present application has been adequately and sufficiently described above by way of embodiments with reference to specific examples and drawings, but it should be recognized that the above-described embodiments can be easily changed and / or modified by those skilled in the art. Therefore, the modified embodiments or the modified embodiments implemented by those skilled in the art can be interpreted as being included in the protection scope of the claims as long as they are within the level of the protection scope of the claims recited in the claims.

[0288] Industrial applicability

[0289] The present application has wide industrial applicability in technical fields related to electronic materials, electronic devices, optical devices, and the like.

Claims

1. A resin composition, characterized by contains: a resin component containing a radical polymerizable compound (A); and a boron nitride filler (B), wherein the boron nitride filler (B) contains agglomerated boron nitride filler (b1) in an amount of 10 to 50% by mass relative to the total amount of the boron nitride filler (B), the thermal conductivity of the cured product is 1.0 W / mK or more and the relative dielectric constant of the cured product is 4.0 or less.

2. The resin composition according to claim 1, wherein the content of the boron nitride filler (B) is 80 to 250 parts by mass relative to 100 parts by mass of the resin component.

3. The resin composition according to claim 1, wherein in the particle size distribution of the agglomerated boron nitride filler (b1), the particle size of 50% by cumulative amount, i.e., D50, is 3.0 to 25.0 μm and the particle size of 90% by cumulative amount, i.e., D90, is 50.0 μm or less. the resin composition.

4. The resin composition according to claim 1, wherein the boron nitride filler (B) contains unagglomerated flaky boron nitride filler (b2).

5. The resin composition according to claim 4, wherein the content of the flaky boron nitride filler (b2) is 50 to 90% by mass relative to the total amount of the boron nitride filler (B).

6. The resin composition according to claim 4, wherein in the particle size distribution of the flaky boron nitride filler (b2), the particle size of 50% by cumulative amount, i.e., D50, is 3.0 to 25.0 μm and the particle size of 90% by cumulative amount, i.e., D90, is 70.0 μm or less.

7. The resin composition according to claim 1, characterized by further contains: a silica filler (C) in an amount of 50 to 150 parts by mass relative to 100 parts by mass of the resin component.

8. The resin composition according to claim 7, wherein in the particle size distribution of the silica filler (C), the particle size of 50% by cumulative amount, i.e., D50, is 0.5 to 10.0 μm and the particle size of 90% by cumulative amount, i.e., D90, is 50.0 μm or less.

9. The resin composition according to claim 1, wherein the radical polymerizable compound (A) contains 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.

10. The resin composition according to claim 1, characterized by further contains: a flame retardant (D).

11. A prepreg, characterized by includes: the resin composition according to any one of claims 1 to 10 or a prepreg of the resin composition; and a fibrous base material.

12. A resin-encased film, characterized by includes: a resin layer containing the resin composition according to any one of claims 1 to 10 or a prepreg of the resin composition; and a support film.

13. A metal foil with resin characterized by includes: a resin layer containing the resin composition according to any one of claims 1 to 10 or a prepreg of the resin composition; and a metal foil.

14. A metal-clad laminate characterized by includes: an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 10; and a metal foil.

15. A wiring board characterized by includes: an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 10; and a wiring.

16. A metal-clad laminate characterized by includes: an insulating layer containing a cured product of the prepreg according to claim 11; and Metal foil.

17. A wiring board characterized by Comprising: an insulation layer comprising a cured article of the prepreg of claim 11; and Wiring.

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