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 thermosetting compound (A) and an inorganic filler (B), the thermosetting compound (A) contains at least one radical polymerizable compound (A1) selected from the group consisting of a polyphenylene ether compound having a reactive unsaturated group, a hydrocarbon compound having a reactive unsaturated group, and a maleimide compound having two or more maleimide groups. The inorganic filler (B) contains a boron nitride filler (B1), and a polydopamine (C) having a functional group (X) that reacts with the radically polymerizable compound (A1) adheres to the surface of the boron nitride filler (B1).

Description

TECHNICAL FIELD

[0001] The present application relates to a resin composition, a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board. BACKGROUND

[0002] For various electronic devices, as the amount of information processing increases, mounting technologies such as high integration of semiconductor devices, high density of wiring, and multilayerization of the semiconductor devices mounted thereon are increasingly developed. In addition, as wiring boards used in various electronic devices, wiring boards that cope with high frequencies such as millimeter wave radar boards for in-vehicle use are sought. For wiring boards used in various electronic devices, in order to increase the transmission speed of signals, it is required to reduce the loss at the time of signal transmission; for wiring boards that cope with high frequencies, it is particularly required to satisfy the above requirement. In order to satisfy this requirement, for a base material that constitutes a base material of a wiring board used in various electronic devices, it is required to have a low dielectric constant and a low dielectric loss factor.

[0003] As such a base material, for example, it is proposed that a PPE-containing resin composition containing PPE (polyphenylene ether), a crosslinking-type curable compound, and a phosphaphenanthrene derivative has excellent low dielectric properties (Patent Document 1).

[0004] On the other hand, for electronic materials used in PA (power amplifier) boards and the like of base stations, in addition to the requirement of low dielectric properties, it is also required to have a high thermal conductivity. So far, as one of the methods for improving the thermal conductivity of a resin composition, a technique of using boron nitride as an inorganic filler is proposed (Patent Document 2).

[0005] The boron nitride filler described in the above Patent Document 2 indeed improves the thermal conductivity of the resin composition. However, when the resin composition is used as a molding material for a substrate material and the like, further excellent adhesion is required. In this regard, it is known that the adhesion of boron nitride to a resin is not sufficient. If the adhesion of an inorganic filler to a resin is poor, the cured product of the resin composition and the like is easily broken, and in the case where the resin composition containing the inorganic filler is used as a substrate material for a metal-clad laminate and the like, the adhesion to a metal foil also becomes poor. In the technique described in Patent Document 2, an aldehyde compound is used as a surface modifier of the inorganic filler in order to improve the thermal conductivity, but the above adhesion problem is not solved.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT DOCUMENTS

[0008] Patent Document 1: Japanese Patent Publication No. 2015-67700

[0009] Patent Literature 2: Japanese Patent Publication No. 2020-73422 SUMMARY

[0010] The present application has been made in view of the circumstances, and aims to provide a resin composition capable of obtaining a cured product which is low in dielectric properties, high in thermal conductivity, and excellent in adhesion. Further, 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.

[0011] 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.

[0012] One technical solution of the present application relates to a resin composition containing a thermosetting compound (A) and an inorganic filler (B), wherein the thermosetting compound (A) contains at least one radical-polymerizable compound (A1) selected from the group consisting of a polyphenylene ether compound having a reactive unsaturated group, a hydrocarbon compound having a reactive unsaturated group, and a maleimide compound having two or more maleimide groups, the inorganic filler (B) contains a boron nitride filler (B1), and a polydopamine (C) having a functional group (X) that reacts with the radical-polymerizable compound (A1) is attached to the surface of the boron nitride filler (B1). BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a schematic cross-sectional view showing an example of a prepreg related to an embodiment of the present application.

[0014] Figure 2 is a schematic cross-sectional view showing an example of a metal-clad laminate related to an embodiment of the present application.

[0015] Figure 3 is a schematic cross-sectional view showing an example of a wiring board related to an embodiment of the present application.

[0016] 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.

[0017] 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

[0018] Hereinafter, an embodiment related to the present application will be specifically described, but the present application is not limited by these descriptions.

[0019] [Resin composition]

[0020] The resin composition according to the present embodiment is a resin composition containing a thermosetting compound (A) and an inorganic filler (B). The thermosetting compound (A) contains at least one radical polymerizable compound (Al) selected from the group consisting of a polyphenylene ether compound having a reactive unsaturated group, a hydrocarbon compound having a reactive unsaturated group, and a maleimide compound having two or more maleimide groups. Further, the inorganic filler (B) contains a boron nitride filler (Bl), and a polydopamine (C) having a functional group (X) that reacts with the radical polymerizable compound (Al) is attached to the surface of the boron nitride filler (Bl).

[0021] According to the above configuration, it is possible to provide a resin composition that can obtain a cured product having low dielectric properties, high thermal conductivity, and excellent adhesion. Further, it is possible to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that are obtained using the resin composition and have excellent properties.

[0022] First, each component of the resin composition according to the present embodiment will be described.

[0023] (Thermosetting compound (A))

[0024] The thermosetting compound (A) according to the present embodiment is a thermosetting compound containing a radical polymerizable compound (Al). The radical polymerizable compound (Al) used in the present embodiment is a compound having radical polymerizability, and examples thereof include a compound having a reactive unsaturated group, a compound having a maleimide group, and the like. More specifically, examples thereof include a polyphenylene ether compound, a cyanate ester compound, an active ester compound, a compound having an unsaturated group, and the like. As the compound having an unsaturated group, examples thereof include an acrylic compound, a methacrylic compound, a vinyl compound, an allyl compound, a propenyl compound, a maleimide compound, a hydrocarbon compound having an unsaturated double bond, and the like.

[0025] Among them, the thermosetting compound (A) according to the present embodiment contains at least one radical polymerizable compound (Al) selected from the group consisting of a polyphenylene ether compound having a reactive unsaturated group, a hydrocarbon compound having a reactive unsaturated group, and a maleimide compound having two or more maleimide groups. By containing these radical polymerizable compounds (Al), it is possible to obtain a resin composition in which the cured product has more excellent low dielectric properties. Hereinafter, each compound will be described in more detail.

[0026] • Polyphenylene ether compound

[0027] The polyphenylene ether compound that can be used in the present embodiment is not particularly limited as long as it is a polyphenylene ether compound having a reactive unsaturated group in the molecule. In the present specification, the "reactive unsaturated group" refers to, for example, a group having an unsaturated double bond or the like. As a specific polyphenylene ether compound having a reactive unsaturated group, for example, a polyphenylene ether compound having a group represented by the following formula (3) or formula (4) or the like can be given. 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.

[0028]

[0029] In formula (3), s represents an integer of 0 to 10. In addition, Z represents an arylene group. Furthermore, R1 to R3 are each independent. That is, R1 to R3 can each be the same group, or can each be a different group. In addition, R1 to R3 represent a hydrogen atom or an alkyl group.

[0030] Note that in formula (3), in the case where s is 0, it is meant that Z is directly bonded to the terminal of the polyphenylene ether.

[0031] The arylene group of the above Z is not particularly limited. As the arylene group, for example, a monocyclic aromatic group such as a phenylene group; a polycyclic aromatic group in which the aromatic group is not a monocyclic ring but a polycyclic ring such as a naphthalene ring; or the like can be given. In addition, 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. In addition, 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, a decyl group, or the like can be given.

[0032]

[0033] In formula (4), R4 represents 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 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, a decyl group, or the like can be given.

[0034] As a preferred specific example of the substituent represented by formula (3), for example, a substituent including a vinylbenzyl group or the like can be given. As the substituent including the vinylbenzyl group, for example, a substituent represented by the following formula (5) or the like can be given. In addition, as the substituent represented by formula (4), for example, an acrylate group, a methacrylate group, or the like can be given.

[0035]

[0036] As the substituent, more specifically, there can be mentioned, for example, vinylbenzyl group (vinylbenzyl group) such as p-vinylbenzyl group and m-vinylbenzyl group, vinylphenyl group, acrylate group, and methacrylate group.

[0037] The polyphenylene ether compound has a polyphenylene ether chain in the molecule, and for example, preferably has a repeating unit represented by the following formula (6) in the molecule.

[0038]

[0039] In formula (6), 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.

[0040] Among R5to R8, as each of the functional groups listed, there can be specifically mentioned, for example, the following groups.

[0041] 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, there can be mentioned, for example, methyl group, ethyl group, propyl group, hexyl group, decyl group, and the like.

[0042] 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, there can be mentioned, for example, vinyl group, allyl group, 3-butenyl group, and the like.

[0043] 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, there can be mentioned, for example, ethynyl group, prop-2-yn-1-yl group (propargyl group), and the like.

[0044] 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, there can be mentioned, for example, acetyl group, propionyl group, butyryl group, isobutyryl group, neopentanoyl group, hexanoyl group, octanoyl group, cyclohexylcarbonyl group, and the like.

[0045] 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, there can be mentioned, for example, acryloyl group, methacryloyl group, crotonoyl group, and the like.

[0046] 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, there can be mentioned, for example, propynoyl group, and the like.

[0047] The weight average molecular weight (Mw) of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 500 to 5000, more preferably 800 to 4000, and further preferably 1000 to 3000. Note that here, the weight average molecular weight is a value obtained by measuring using a usual molecular weight measuring method, and specifically, a value measured using gel permeation chromatography (GPC) or the like can be cited. In addition, in the case where the polyphenylene ether compound has the repeating unit represented by the formula (6) in the molecule, t is preferably a number such that the weight average molecular weight of the polyphenylene ether compound is within the above range. Specifically, t is preferably 1 to 50.

[0048] If the weight average molecular weight of the polyphenylene ether compound is within the above range, the polyphenylene ether compound not only has the excellent low dielectric properties possessed by polyphenylene ether, but also has more excellent heat resistance of the cured product, and also has excellent moldability. This is considered to be based on the following reasons. In a usual polyphenylene ether, if the weight average molecular weight thereof is within the above range, the molecular weight is low, and thus there is a tendency that the heat resistance of the cured product decreases. In this regard, it is considered that since the polyphenylene ether compound involved in the present embodiment has one or more unsaturated double bonds at the terminal, the heat resistance of the cured product can be made sufficiently high. In addition, it is considered that if the weight average molecular weight of the polyphenylene ether compound is within the above range, the moldability is also excellent because the molecular weight is relatively low. Thus, it is considered that the polyphenylene ether compound can obtain the effect that not only the heat resistance of the cured product is more excellent, but also the moldability is excellent.

[0049] The average number of the substituents (the number of terminal functional groups) possessed by each molecule of the polyphenylene ether compound at the terminal of the molecule 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 it is difficult to obtain a cured product having sufficient heat resistance. 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 properties of the resin composition, or a decrease in flowability of the resin composition, or the like can occur.

[0050] Note that the number of terminal functional groups of the polyphenylene ether compound can be exemplified by a value indicating an average of the number of the substituents per one molecule of all modified polyphenylene ether compounds present in 1 mole of the polyphenylene ether compound, and the like. The number of terminal functional groups can be determined, for example, by determining the number of hydroxyl groups remaining in the obtained modified polyphenylene ether compound and calculating the amount of reduction from the number of hydroxyl groups of the polyphenylene ether before modification. The amount of reduction from the number of hydroxyl groups of the polyphenylene ether before modification is the number of terminal functional groups. Further, the method for determining 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 determined.

[0051] As the polyphenylene ether compound of the present embodiment, a modified polyphenylene ether compound represented by the following formula (7), a modified polyphenylene ether compound represented by the following formula (8), and the like can be exemplified. Further, as the polyphenylene ether compound of the present embodiment, these modified polyphenylene ether compounds can be used alone, or two kinds of the modified polyphenylene ether compounds can be used in combination.

[0052]

[0053]

[0054] In formula (7) and formula (8), R9to 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. X1and X2each independently represent a substituent having a carbon-carbon unsaturated double bond. A and B each represent a repeating unit represented by the following formula (9) and the following formula (10), respectively. Further, in formula (8), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms.

[0055]

[0056]

[0057] In formula (9) and formula (10), m and n each represent 0 to 20. R 25 to R 28 and R 29 to R 32 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0058] The modified polyphenylene ether compound represented by the formula (7) and the modified polyphenylene ether compound represented by the formula (8) are not particularly limited as long as they are compounds satisfying the above constitution. Specifically, in the formula (7) and the formula (8), R9to R 16 and R 17 to R 24 are each independently the same or different. That is, R9to R 16 and R 17 to R 24 may be the same or different. In addition, R9to R 16 and R 17 to 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.

[0059] In the formula (9) and the formula (10), m and n each preferably represent a number of 0 to 20 as described above. In addition, for m and n, the total of m and n is preferably represented by a number of 1 to 30. Therefore, it is more preferred that m represents a number of 0 to 20, n represents a number of 0 to 20, and the total of m and n represents a number of 1 to 30. In addition, R 25 to R 28 and R 29 to R 32 are each independently the same or different. That is, R 25 to R 28 and R 29 to R 32 may be the same or different. In addition, R 25 to R 28 and R 29 to R 32 represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. Of these, a hydrogen atom and an alkyl group are preferred.

[0060] R9to R 32 are the same as R5to R8in the above formula (6).

[0061] In the formula (8), 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 formula (11) shown below, or the like can be exemplified.

[0062]

[0063] In the formula (11), R 33 and R 34each independently represents a hydrogen atom or an alkyl group. As the alkyl group, for example, a methyl group can be mentioned. Further, as the group represented by formula (11), for example, methylene, methylmethylene and dimethylmethylene can be mentioned, of which dimethylmethylene is preferred.

[0064] In the formula (7) and the formula (8), X1and X2each independently represent a substituent having a carbon-carbon unsaturated double bond. As the substituents X1and X2, there is no particular limitation as long as they are substituents having a carbon-carbon unsaturated double bond. As the substituents X1and X2, for example, the substituents represented by the above formula (3) and the substituents represented by the above formula (4) can be mentioned. Note that in the modified polyphenylene ether compound represented by the formula (7) and the modified polyphenylene ether compound represented by the formula (8), X1and X2may be the same substituent or different substituents.

[0065] As a more specific example of the modified polyphenylene ether compound represented by the formula (7), for example, a modified polyphenylene ether compound represented by the following formula (12) can be mentioned.

[0066]

[0067] As a more specific example of the modified polyphenylene ether compound represented by the formula (8), for example, a modified polyphenylene ether compound represented by the following formula (13) and a modified polyphenylene ether compound represented by the following formula (14) can be mentioned.

[0068]

[0069]

[0070] In the above formula (12) to formula (14), m and n are the same as m and n in the above formula (9) and the above formula (10). Further, in the above formula (12) and the above formula (13), R1to R3, p and Z are the same as R1to R3, s and Z in the above formula (3), respectively. Further, in the above formula (13) and the above formula (14), Y is the same as Y in the above formula (8). Further, in the above formula (14), R4is the same as R4in the above formula (4).

[0071] 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 loss factor and excellent heat resistance and the like, and also to improve Tg and adhesion.

[0072] Note that the modified polyphenylene ether compound can be used alone or in combination of two or more.

[0073] 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.

[0074] • Hydrocarbon compound having a reactive unsaturated group

[0075] As the hydrocarbon compound that can be used in the present embodiment, there is no particular limitation as long as it is a hydrocarbon compound having a reactive unsaturated group in the molecule, and preferred examples include, for example, a multifunctional vinyl aromatic polymer, a cyclic polyolefin resin, and a hydrocarbon resin of a vinyl aromatic compound-conjugated diene copolymer.

[0076] The multifunctional vinyl aromatic polymer preferably contains a polymer obtained by polymerizing at least a multifunctional 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 multifunctional 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 multifunctional vinyl aromatic compound and / or a derivative thereof.

[0077] Further, in addition to the multifunctional vinyl aromatic compound and / or a derivative thereof structural unit, more than one kind of structural unit derived from a reactive monomer can also be contained. The reactive monomer is not particularly limited, and for example, it can be a multifunctional vinyl aromatic copolymer having a structural unit derived from a monovinyl aromatic compound such as styrene.

[0078] More specifically, for example, a multifunctional vinyl compound having two or more vinyl groups in the molecule can be exemplified. Also, as the multifunctional vinyl compound, for example, divinylbenzene, divinyl naphthalene, divinyl biphenyl, polybutadiene, and the like can be exemplified.

[0079] • Maleimide compound

[0080] As the maleimide compound that can be used in the present embodiment, there is no particular limitation as long as it is a compound having two or more maleimide groups in the molecule. More specifically, as the maleimide compound, a multifunctional maleimide compound having two or more maleimide groups in the molecule, a modified maleimide compound thereof, and the like can be exemplified. 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, and 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 exemplified.

[0081] More specifically, examples of the maleimide compound that can be cited include 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 6 or more carbon atoms and an alkylene group having 6 or more carbon atoms, and a maleimide compound having a benzene ring in the molecule, and the like.

[0082] The maleimide compound used in the present embodiment can be a commercially available product, and examples of the maleimide compound that can be used include MIR-3000, MIR-5000 manufactured by Japan Eubacco Co., Ltd.; BMI-4000, BMI-2300, BMI-TMH, BMI-4000, BMI-5100 manufactured by Dainippon Ink and Chemicals, Inc.; BMI-689, BMI-1500, BMI-3000J, BMI-5000 manufactured by Designer Molecules Inc.

[0083] • Other thermosetting compound (curing agent)

[0084] The resin composition of the present embodiment can also contain a thermosetting compound other than the radical-polymerizable compound (Al) described above. In this case, the thermosetting compound is preferably a thermosetting compound that functions as a curing agent capable of reacting with the radical-polymerizable compound described above.

[0085] Specifically, as the curing agent, examples of the thermosetting compound include a phenol resin, a benzoxazine compound, a styrene compound, a styrene derivative, a compound having an acryloyl group in the molecule, a compound having a methacryloyl group in the molecule, a compound having a vinyl group in the molecule, a compound having an allyl group in the molecule, a compound having an acenaphthylene structure in the molecule, an isocyanurate compound having an isocyanurate group in the molecule, a monomaleimide compound, and the like. These can be used alone, or the radical-polymerizable compound (Al) described above and two or more curing agents can be used in combination.

[0086] As the benzoxazine compound, a benzoxazine compound represented by the following general formula (15) can be used, for example.

[0087]

[0088] In formula (15), R a represents a k-valent group, R b each independently represents a halogen atom, an alkyl group, or an aryl group. k represents an integer of 2 to 4, and 1 represents an integer of 0 to 4.

[0089] As commercially available products, "JBZ-OP100D", "ODA-BOZ" manufactured by JFE Chemical Corporation; "P-d", "F-a", "ALP-d" manufactured by Shikoku Chemicals Corporation; and "HFB2006M" manufactured by Showa Highpolymer Co., Ltd. and the like can be exemplified.

[0090] As the styrene compound, there is no particular limitation as long as it is a compound having a styrene skeleton in the molecule, and a preferable example is a resin compound having a styrene skeleton at the terminal or the like.

[0091] As the styrene derivative, for example, bromostyrene, dibromostyrene and the like can be exemplified.

[0092] The compound having an acryloyl group in the molecule is an acrylate compound. As the acrylate compound, a monofunctional acrylate compound having one acryloyl group in the molecule, and a multifunctional acrylate compound having two or more acryloyl groups in the molecule can be exemplified. As the monofunctional acrylate compound, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate and the like can be exemplified. As the multifunctional acrylate compound, for example, tricyclodecanedimethanol diacrylate and the like can be exemplified.

[0093] The compound having a methacryloyl group in the molecule is a methacrylate compound. As the methacrylate compound, a monofunctional methacrylate compound having one methacryloyl group in the molecule, and a multifunctional methacrylate compound having two or more methacryloyl groups in the molecule can be exemplified. As the monofunctional methacrylate compound, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate and the like can be exemplified. As the multifunctional methacrylate compound, for example, tricyclodecanedimethanol dimethacrylate and the like can be exemplified.

[0094] The compound having a vinyl group in the molecule is a vinyl compound. As the vinyl compound, a monofunctional vinyl compound (monovinyl compound) having one vinyl group in the molecule and the like can be exemplified.

[0095] The compound having an allyl group in the molecule is an allyl compound. As the allyl compound, a monofunctional allyl compound having one allyl group in the molecule, and a multifunctional allyl compound having two or more allyl groups in the molecule can be exemplified. As the multifunctional allyl compound, for example, diallyl phthalate (DAP) and the like can be exemplified.

[0096] The compound having aacenaphthylene structure in the molecule is an aacenaphthylene compound. As the aacenaphthylene compound, there can be mentioned, for example, aacenaphthylene, alkyl aacenaphthylene compounds, halogenated aacenaphthylene compounds, and phenyl aacenaphthylene compounds. As the alkyl aacenaphthylene compounds, there can be mentioned, for example, 1-methyl aacenaphthylene, 3-methyl aacenaphthylene, 4-methyl aacenaphthylene, 5-methyl aacenaphthylene, 1-ethyl aacenaphthylene, 3-ethyl aacenaphthylene, 4-ethyl aacenaphthylene, 5-ethyl aacenaphthylene, and the like. As the halogenated aacenaphthylene compounds, there can be mentioned, for example, 1-chloro aacenaphthylene, 3-chloro aacenaphthylene, 4-chloro aacenaphthylene, 5-chloro aacenaphthylene, 1-bromo aacenaphthylene, 3-bromo aacenaphthylene, 4-bromo aacenaphthylene, 5-bromo aacenaphthylene, and the like. As the phenyl aacenaphthylene compounds, there can be mentioned, for example, 1-phenyl aacenaphthylene, 3-phenyl aacenaphthylene, 4-phenyl aacenaphthylene, 5-phenyl aacenaphthylene, and the like. As the aacenaphthylene compound, there can be either a monofunctional aacenaphthylene compound having one aacenaphthylene structure in the molecule as mentioned above or a multifunctional aacenaphthylene compound having two or more aacenaphthylene structures in the molecule.

[0097] The compound having an isocyanurate group in the molecule is an isocyanurate compound. As the isocyanurate compound, there can be mentioned, for example, a compound having an alkenyl group in the molecule (an alkenyl isocyanurate compound) and the like, and there can be mentioned, for example, a trienyl isocyanurate compound such as triallyl isocyanurate (TAIC) and the like.

[0098] In the above, it is preferable to use, for example, a benzoxazine compound, an isocyanurate compound having an isocyanurate group in the molecule, an N-phenyl maleimide, a resin compound in which a terminal is modified with a styrene skeleton, and the like.

[0099] The thermosetting compound used as the curing agent as mentioned above can be used alone or in combination of two or more.

[0100] In the resin composition of the present embodiment, the content of the thermosetting compound (A) is preferably 15 to 60 parts by mass, more preferably 20 to 55 parts by mass, with respect to 100 parts by mass of the total of the thermosetting compound (A) and the inorganic filler (B). It is considered that if the content of the thermosetting compound (A) is within the above range, a resin composition capable of obtaining a cured product having low dielectric properties and high heat resistance can be more reliably obtained.

[0101] In the case where the resin composition of the present embodiment contains, in addition to the radical-polymerizable compound (Al), a thermosetting compound (a compound functioning as a curing agent), the content ratio thereof is preferably, in terms of mass ratio, the radical-polymerizable compound (Al): other thermosetting compound, about 95:5 to 50:50. If the content ratio is within this range, a resin composition whose cured product is more excellent in heat resistance is obtained. The reason for this is considered to be that the curing reaction of the resin component of the present embodiment and the curing agent proceeds favorably.

[0102] (Inorganic filler (B))

[0103] • Boron nitride filler (B1)

[0104] The resin composition according to the present embodiment further contains an inorganic filler (B) containing a boron nitride filler (B1). The boron nitride filler (B1) is not particularly limited as long as it can be used as the inorganic filler contained in the resin composition. In the present embodiment, as the boron nitride filler (B1), hexagonal boron nitride (h-BN) having a layered structure of a graphite type, cubic boron nitride (c-BN) having a diamond type, and amorphous boron nitride (a-BN), and the like can be used. Since h-BN is relatively easy to synthesize, and has characteristics that the thermal conductivity, the electrical insulation, the chemical stability, and the heat resistance are excellent, it is particularly useful. In addition, as the boron nitride filler (B1), a boron nitride particle can be used. The boron nitride particle is generally white. The shape of the boron nitride particle is not particularly limited. The shape of the boron nitride particle can be, for example, a scale shape, a spherical shape, an oval spherical shape, a rod shape, or the like.

[0105] The average particle diameter of the boron nitride particle is not particularly limited. The average particle diameter of the boron nitride particle can be, for example, 0.05 μm or more and 100 μm or less, or 0.1 μm or more and 50 μm or less. In the present embodiment, the average particle diameter of the boron nitride particle refers to the median diameter. The median diameter refers to the particle diameter (d50) at which the cumulative volume in the particle size distribution on a volume basis is equal to 50%. The particle size distribution on a volume basis is measured, for example, by a laser diffraction type measuring device.

[0106] On the surface of the boron nitride filler (B1) according to the present embodiment, a polydopamine (C) having a functional group (X) that reacts with the radical polymerizable compound (A1) is attached. The polydopamine (C) can also cover at least a part of the surface of the boron nitride filler (B1). In this case, the polydopamine (C) can cover the entire surface of the boron nitride filler (B1), or can cover only a part of the surface of the boron nitride filler (B1).

[0107] • Polydopamine

[0108] The polydopamine is a polymer of dopamine, and can have a repeating unit represented by the following formula (16), for example. However, in the following formula (16), the indoline skeleton portion can also be an indole skeleton.

[0109]

[0110] In the above structural formula (16), n is an integer of 1 or more, and particularly an integer of 2 or more.

[0111] As shown in the above formula (16), the polydopamine can have an indoline skeleton and / or an indole skeleton. However, the polydopamine can also have a structure that is not completely cyclized. That is, a primary amine and a secondary amine can be mixed in the polydopamine. Furthermore, in formula (16), the 5,6-dihydroxyindoline moiety can also have any one of the quinone structures shown in the following structural formulas.

[0112]

[0113] The polydopamine to which a functional group (X) is introduced is a polydopamine (C) of the present embodiment. That is, the polydopamine (C) of the present embodiment has a functional group (X) that reacts with the radical polymerizable compound (A1). By causing the polydopamine (C) having a functional group (X) that reacts with the radical polymerizable compound (A1) to adhere to the boron nitride filler (B1), the adhesion of the radical polymerizable compound (A1) to the boron nitride filler (B1) can be improved. As a result, peeling between the inorganic filler (B) and the thermosetting resin (A) can be suppressed, and the adhesion of the resin composition to a metal foil or the like can be improved. Furthermore, a part of the functional group (X) derived from dopamine in the polydopamine (C) can also be changed.

[0114] The polydopamine (C) can also have a thin film shape on the surface of the boron nitride filler (B1). The thin film thickness of the polydopamine (C) is, for example, 0.1 nm to 300 nm, and more preferably 0.1 nm to 100 nm. The thin film of the polydopamine (C) can cover at least a part of the surface of the boron nitride filler (B1), or can cover the entire surface of the boron nitride filler (B1).

[0115] The functional group (X) is not particularly limited as long as it is a functional group that reacts with the radical polymerizable compound (A1) and the thermosetting compound (thermosetting compound that functions as a curing agent).

[0116] For example, the functional group (X) possessed by the polydopamine (C) preferably includes at least one selected from the group consisting of an epoxy group, an anilino group, a vinyl group, an acrylic acid group, a methacrylic acid group, an allyl group, a styrene structure, and a maleimide group.

[0117] Note that, in the present specification, the "styrene structure" refers to the structure shown in the following formula (S).

[0118]

[0119] • A method for manufacturing a boron nitride filler (B1) to which a polydopamine (C) having a functional group (X) that reacts with a radical polymerizable compound (A1) is attached

[0120] The boron nitride filler (B1) of the present embodiment is obtained, for example, by attaching polydopamine to the surface of the boron nitride filler, and then introducing a functional group (X) into the attached polydopamine, to obtain a boron nitride filler (B1) having polydopamine (C) having a functional group (X) attached to the surface. Note that, before the functional group (X) is introduced into the polydopamine, the boron nitride filler having the polydopamine attached to the surface can be subjected to a heat treatment.

[0121] The method of attaching polydopamine to the surface of the boron nitride filler is not particularly limited, and polydopamine can be attached to the surface of the boron nitride filler by oxidatively polymerizing dopamine by bringing a dopamine solution into contact with the boron nitride filler.

[0122] The dopamine solution is obtained, for example, by adding dopamine hydrochloride to a Tris-HCl solution adjusted to pH 8.5 and stirring. The concentration of the dopamine solution is not particularly limited, and is in the range of 0.01 mg / mL to 30 mg / mL, for example. The pH of the dopamine solution is in the range of pH 6 to pH 11, and can also be in the range of pH 8 to pH 10. The pH of the dopamine solution can be adjusted by mixing with a Tris-HCl solution or the like. The temperature of the dopamine solution at the time of oxidative polymerization is, for example, 10°C to 100°C. The polymerization time is, for example, 1 hour to 48 hours.

[0123] Further, in the case where a polydopamine layer (thin film of polydopamine) is formed so as to cover at least a part of the surface of the boron nitride filler, the maximum value of the thickness of the polydopamine layer is preferably, for example, 0.1 nm or more and 100 nm or less. By virtue of this, it is possible to improve the adhesion to the thermosetting resin while maintaining the low dielectric loss tangent possessed by boron nitride. The thickness of the polydopamine layer can be controlled by the polymerization time.

[0124] The heat treatment of the boron nitride filler can be performed after the polydopamine is attached to the surface. By virtue of this, a polydopamine film having a higher purity can be obtained. The method of the heat treatment is not particularly limited. The heat treatment can be performed using a publicly known heat treatment device such as a sintering device, an electric furnace, or a hot plate. In particular, since temperature adjustment is easy, it is preferable to perform the heat treatment using a sintering device or an electric furnace.

[0125] The heat treatment can be performed by heating the temperature of the surroundings of the boron nitride filler to a range of 100°C or more and 400°C or less. The heating time is, for example, 1 hour or more and 48 hours or less.

[0126] Then, a functional group (X) is introduced into the polydopamine attached to the surface of the boron nitride filler. By virtue of this, a polydopamine layer is formed from the polydopamine (C). The introduction of the functional group (X) is not particularly limited, and can be performed, for example, by an acylation treatment or a treatment using a silane coupling agent.

[0127] The acylation treatment of the polydopamine (C) can be performed by reacting the polydopamine and an acylating agent in the presence of a catalyst to acylate at least a part of the hydroxyl groups possessed by the polydopamine, thereby introducing the functional group (X).

[0128] The acylating agent is not particularly limited as long as it can react with the polar functional groups such as the hydroxyl groups contained in the polydopamine to acylate them. The acylating agent can also be an acid anhydride. As a publicly known acylating agent, for example, a carboxylic acid anhydride can be mentioned. More specifically, methacrylic anhydride, acetic anhydride, benzoic anhydride, propionic anhydride, and the like can be mentioned. The acid anhydride can also contain at least one selected from the group consisting of methacrylic anhydride, acrylic anhydride, acetic anhydride, and benzoic anhydride. In the case where the acylating agent has a double bond at the terminal thereof, the double bond reacts with the reactive residue of the resin of the insulating layer to form a bond, thereby improving the adhesion of the thermosetting compound (A) to the inorganic filler (B). From this viewpoint, the acylating agent is particularly preferably methacrylic anhydride or acetic anhydride.

[0129] Further, in addition to the acylation treatment as described above, the functional group (X) can also be introduced into the polydopamine (C) by performing a treatment using a silane coupling agent having various functional groups.

[0130] As the silane coupling agent, for example, a methacryl silane coupling agent, a vinyl silane coupling agent, a styryl silane coupling agent, an acryl silane coupling agent, a phenylamino silane coupling agent, an epoxy silane coupling agent, a maleimide silane coupling agent, and the like can be mentioned. The treatment method using the silane coupling agent is not particularly limited, and for example, by mixing the boron nitride filler to which the polydopamine is attached in an aqueous solution containing a silane coupling agent having the functional group (X), followed by drying, a polydopamine (C) in which at least a part of the hydroxyl groups contained in the polydopamine is substituted with the functional group (X) as described above can be obtained.

[0131] In the case where the above-described acylation treatment or the treatment for introducing the functional group (X) using the above-described silane coupling agent is performed, the polydopamine (C) of the present embodiment can also have at least one structure selected from the structures represented by the following Formula (1) and the following Formula (2).

[0132]

[0133]

[0134] It is considered that by having such a structure, the advantage of having a stronger bond between the thermosetting resin cured product (A) and the boron nitride filler to which the polydopamine film (C) is attached is provided.

[0135] • Other inorganic fillers

[0136] The resin composition of the present embodiment can contain only the boron nitride filler (B1) as the inorganic filler (B), or can contain an inorganic filler other than the boron nitride filler (B1).

[0137] As the inorganic filler other than the boron nitride filler (B1), there is no particular limitation as long as it can be used as an inorganic filler contained in the resin composition. Examples thereof include a boron nitride filler other than the boron nitride filler (B1), a silica filler, a metal oxide filler (alumina filler, titania filler, magnesium oxide, mica, and the like), a metal hydroxide filler (aluminum hydroxide filler, magnesium hydroxide, and the like), a talc filler, an aluminum borate filler, a barium sulfate filler, an aluminum nitride filler, a silicon nitride filler, a magnesium carbonate filler (anhydrous magnesium carbonate, and the like), a calcium carbonate filler, and the like. Among them, as the inorganic filler other than the boron nitride filler (B1), a silica filler, an anhydrous magnesium carbonate filler, an alumina filler, a silicon nitride filler, and a boron nitride filler having no dopamine attached to the surface are preferable. The silica filler is not particularly limited, and examples thereof include a pulverized silica filler, a silica particle filler, and the like, with a silica particle filler being preferable. Further, the magnesium carbonate filler is not particularly limited, and an anhydrous magnesium carbonate (synthetic magnesite) filler is preferable.

[0138] The inorganic filler other than the boron nitride filler (B1) can be an inorganic filler subjected to surface treatment, or an inorganic filler not subjected to surface treatment. Further, as the surface treatment, a treatment with a silane coupling agent, and the like can be exemplified.

[0139] The content of the inorganic filler (B) is preferably 40 to 85 parts by mass, and more preferably 40 to 80 parts by mass, relative to 100 parts by mass of the total of the thermosetting compound (A) and the inorganic filler (B). Further, the content of the boron nitride filler (B1) in the inorganic filler (B) is preferably 10 to 90% by mass, and more preferably 10 to 70% by mass, relative to the total amount of the inorganic filler (B). It is considered that, by having the content of the boron nitride filler (B1) within the range, it is possible to ensure high thermal conductivity and adhesion.

[0140] (Silane Coupling Agent)

[0141] The resin composition of the present embodiment can also contain a silane coupling agent. It is considered that, by this, it is possible to more reliably replace the hydroxyl groups in the polydopamine (C) with the functional group (X), and thus, it is possible to further improve the adhesion of the resin component to boron nitride.

[0142] 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 methacryloyl group, an acryloyl group, and an anilino group, and 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 methacryloyl group, an acryloyl group, and an anilino group as a reactive functional group and having a hydrolyzable group such as a methoxy group or an ethoxy group, and the like can be exemplified.

[0143] As the silane coupling agent, as a silane coupling agent having a vinyl group, for example, vinyltriethoxysilane, vinyltrimethoxysilane, and the like can be exemplified. As the silane coupling agent, as a silane coupling agent having a styryl group, for example, p-styryltrimethoxysilane and p-styryltriethoxysilane having a styrene structure represented by the above formula (S), and the like can be exemplified. As the silane coupling agent, as a silane coupling agent having a methacryloyl group, for example, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, and 3-methacryloyloxypropylethyldiethoxysilane, and the like can be exemplified. As the silane coupling agent, as a silane coupling agent having an acryloyl group, for example, 3-acryloyloxypropyltrimethoxysilane and 3-acryloyloxypropyltriethoxysilane, and the like can be exemplified. As the silane coupling agent, as a silane coupling agent having an anilino group, for example, N-phenyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltriethoxysilane, and the like can be exemplified.

[0144] In the case where the resin composition of the present embodiment contains a silane coupling agent, the content thereof is preferably about 0.1 to 10 parts by mass with respect to 100 parts by mass of the thermosetting compound (A).

[0145] (Reaction Initiator)

[0146] 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 at which curing proceeds, and thus a reaction initiator can also be added.

[0147] The reaction initiator is not particularly limited as long as it can promote the curing reaction of the resin composition. Specifically, for example, a metal oxide, an azo compound, a peroxide, and the like can be exemplified, and more preferably at least one of a peroxide and an azo compound is contained.

[0148] As the metal oxide, specifically, a carboxylic acid metal salt, and the like can be exemplified.

[0149] As the organic peroxide, α, α'-di (t-butylperoxy) diisopropylbenzene, 2, 5-dimethyl-2, 5-di (t-butylperoxy) -3-hexyne, benzoyl peroxide, 3, 3', 5, 5'-tetramethyl-1, 4-benzenediol benzohydroquinone, chloranil, 2, 4, 6-tri-t-butylphenoxy, t-butylperoxy isopropyl monocarbonate, azobisisobutyronitrile, and the like can be exemplified.

[0150] 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.

[0151] The reaction initiator as described above can be used alone, or two or more can be used in combination.

[0152] In the case where the resin composition of the present embodiment contains the reaction initiator as described above, the content thereof is not particularly limited, and, for example, 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 thermosetting compound (A) is preferable.

[0153] (Other components)

[0154] The resin composition to which the present embodiment relates can further contain a component other than the above-described components (other components) as needed within a range not impairing the effects of the present application. As the other components contained in the resin composition to which the present embodiment relates, additives such as a flame retardant, 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 manufacturing)

[0156] As the method for manufacturing the resin composition of the present embodiment, there is no particular limitation, and, for example, a method in which the thermosetting compound (A) and other organic components added as needed are mixed, and then an inorganic filler (B) 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 description of the prepreg to be described later, and the like can be exemplified.

[0157] Further, by using the resin composition to which the present embodiment relates, a prepreg, a metal-clad laminate, a wiring board, a metal foil with resin, and a film with resin can be obtained as described below.

[0158] Preferably, the cured product of the resin composition has a thermal conductivity of 1.0 W / m-K or more and a dielectric loss factor of 0.003 or less at a frequency of 10 GHz. As described above, by using the resin composition of the present embodiment, both high thermal conductivity and low dielectric properties of the cured product thereof can be achieved, and excellent adhesion can also be obtained. The upper limit of the thermal conductivity is not particularly limited, and from the viewpoint of the filling property of the inorganic filler into the resin composition, it is preferably 50 W / m-K or less.

[0159] [Prepreg]

[0160] Figure 1 is a schematic cross-sectional view showing an example of a prepreg 1 to which the present embodiment is applied. In the following description, each symbol represents the following content: 1 prepreg, 2 resin composition or semi-cured product of the resin composition, 3 fibrous base material, 11 metal-clad foil 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.

[0161] As shown in Figure 1 , the prepreg 1 to which the present embodiment is applied has: the resin composition or semi-cured product of the resin composition 2; and the fibrous base material 3. The prepreg 1 has: the resin composition or semi-cured product of the resin composition 2; and the fibrous base material 3 present in the resin composition or semi-cured product of the resin composition 2.

[0162] Note that, in the present embodiment, the semi-cured product is a substance in a state in which the resin composition is cured to an intermediate stage to a degree that further curing is possible. That is, the semi-cured product is a substance in a state (B-stage) in which the resin composition is semi-cured. For example, if the resin composition is heated, the viscosity initially gradually decreases, and then starts to cure, and the viscosity gradually increases. In this case, as the semi-cured state, a state during a period from the start of the increase in viscosity to before the completion of the curing can be cited.

[0163] Further, as the prepreg obtained by using the resin composition to which the present embodiment is applied, as described above, it can be a prepreg having a semi-cured product of the resin composition, and further, it can be a prepreg having the resin composition that is not cured. That is, it can be a prepreg having a semi-cured product (B-stage resin composition) of the resin composition and a fibrous base material, and it can be a prepreg having the resin composition before curing (A-stage resin composition) and a fibrous base material. Further, as the resin composition or semi-cured product of the resin composition, it can be a substance obtained by drying or heat-drying the resin composition.

[0164] In the production of the prepreg, the resin composition 2 is used mostly as a varnish in order to be impregnated into the fibrous base material 3 which is a base material for forming the prepreg. That is, the resin composition 2 is usually 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.

[0165] 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 dispersed to a specified dispersion state using a ball mill, a bead mill, a planetary mixer, a roll mill, etc., 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 modified polyphenylene ether compound and the curing agent, etc. and does not hinder the curing reaction. Specifically, for example, toluene, methyl ethyl ketone (MEK), etc. can be mentioned.

[0166] 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 used mostly as a resin varnish as described above.

[0167] 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 roll 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.

[0168] 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 used mostly as a resin varnish as described above.

[0169] 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, etc. The impregnation can be performed repeatedly as necessary. Also at this time, the final desired composition and impregnation amount can be adjusted by repeatedly impregnating a plurality of resin compositions which differ in composition or concentration.

[0170] The fibrous base material 3 impregnated with the resin composition (resin varnish) 2 is heated under a desired heating condition (for example, 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.

[0171] The prepreg having the resin composition or the semi-cured product of the resin composition according to the present embodiment is a prepreg from which a cured product having low dielectric properties, high thermal conductivity, and excellent adhesion can be suitably obtained.

[0172] [Metal-clad laminate]

[0173] Figure 2 is a schematic cross-sectional view showing an example of a metal-clad laminate 11 according to the present embodiment.

[0174] As shown in Figure 2 , the metal-clad 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 metal-clad laminate 11 includes: the insulating layer 12 including a cured product of the 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 varies depending on the performance and the like required for the wiring board finally obtained, and is not particularly limited. The thickness of the metal foil 13 can be appropriately set depending on the intended purpose, and is preferably, for example, 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, a carrier-equipped copper foil having a release layer and a carrier can be used in order to improve handleability.

[0175] 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 piece of the prepreg 1 or overlapping a plurality of pieces of the prepreg 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 laminate or a one-surface metal-clad laminate 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, or the like. For example, the temperature can be set to 170 to 230°C, the pressure can be set to 3 to 4 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 can be exemplified.

[0176] The metal-clad laminate having the insulating layer containing the cured product of the resin composition according to the embodiment is a metal-clad laminate having an insulating layer which is low in dielectric properties, high in thermal conductivity, and excellent in adhesion to a metal foil.

[0177] [Wire board]

[0178] Figure 3 is a schematic cross-sectional view showing an example of the wire board 21 according to the embodiment.

[0179] As shown in Figure 3 , the wire board 21 according to the embodiment has: an insulating layer 12 formed by curing the prepreg 1 shown in Figure 1 ; and a wire 14 formed by laminating the insulating layer 12 and removing a part of the metal foil 13. That is, the wire board 21 has: the insulating layer 12 containing the cured product of the resin composition; and the wire 14 provided on the insulating layer 12. Further, the insulating layer 12 can be formed of the cured product of the resin composition or the cured product of the prepreg.

[0180] 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 manufacturing the wiring board 21 using the prepreg 1, and the like can be exemplified. 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 manufactured as described above, thereby manufacturing 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 exemplified. 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 obtain. 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: Semi Additive Process) or a modified semi-additive process (MSAP: Modified Semi Additive Process), and the like can be exemplified. The wiring board 21 has the insulating layer 12 which has low dielectric properties and high heat resistance, and which can maintain the low dielectric properties well even after water absorption treatment.

[0181] The wiring board is a wiring board having an insulating layer which has low dielectric properties, high thermal conductivity, and excellent adhesion to a metal foil.

[0182] [Resin-coated metal foil]

[0183] Figure 4 is a schematic cross-sectional view showing an example of the resin-coated metal foil 31 to which the present embodiment is directed.

[0184] As shown in Figure 4 , the resin-coated metal foil 31 to which the present embodiment is directed has: a resin layer 32 containing the resin composition or the semi-cured product of the resin composition; and a metal foil 13. The resin-coated metal foil 31 has the metal foil 13 on the surface of the resin layer 32. That is, the resin-coated metal foil 31 has: the resin layer 32; and the metal foil 13 laminated together with the resin layer 32. Further, the resin-coated metal foil 31 can have other layers between the resin layer 32 and the metal foil 13.

[0185] Further, as the resin layer 32, 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 metal foil 31 can be a resin-coated metal foil provided with a resin layer including a prepreg of the resin composition (the resin composition in the B-stage) and a metal foil, or can be a resin-coated metal foil provided with a resin layer including the resin composition before curing (the resin composition in the A-stage) and a metal foil. 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.

[0186] 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 listed.

[0187] The resin-coated metal foil 31 and the resin-coated film 41 can be provided with a cover film as necessary. By being provided with a cover film, the mixing-in 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 listed.

[0188] 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 a varnish-like resin composition (resin varnish) to the metal foil 13 and performing heating can be listed. 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 resin composition after heating is formed as the 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.

[0189] The resin-coated metal foil provided with a resin layer including the resin composition or the prepreg of the resin composition according to the present embodiment is a resin-coated metal foil in which a cured product having low dielectric properties, high thermal conductivity, and excellent adhesion to a metal foil can be suitably obtained.

[0190] [Resin-coated film]

[0191] Figure 5is a schematic cross-sectional view showing an example of the resin-attached film 41 to which the present embodiment is applied.

[0192] As shown in Figure 5 the resin-attached film 41 to which the present embodiment is applied includes: a resin layer 42 including the resin composition or the semi-cured product of the resin composition; and a support film 43. The resin-attached film 41 includes the resin layer 42 and the support film 43 laminated together with the resin layer 42. Further, the resin-attached film 41 can include other layers between the resin layer 42 and the support film 43.

[0193] Further, as the resin layer 42, a semi-cured product of the resin composition as described above can be included, and further, the uncured resin composition can be included. That is, the resin-attached film 41 can be a resin-attached film including a resin layer including a semi-cured product (a second-order resin composition) of the resin composition and a support film, and can be a resin-attached film including a resin layer including the resin composition before curing (a first-order resin composition) and a support film. Further, as the resin layer, as long as the resin composition or the semi-cured product of the resin composition is included, 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 a prepreg can be used.

[0194] Further, as the support film 43, a support film used in a resin-attached 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.

[0195] The resin-attached film 41 can include a cover film or the like as needed. By including a cover film, the mixing 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.

[0196] 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 needed can be used.

[0197] The method of producing the resin-coated film 41 is not particularly limited as long as the resin-coated film 41 can be produced. The method of producing the resin-coated film 41 can include, for example, a method of applying the above-mentioned varnish-like resin composition (resin varnish) to the support film 43 and performing heating. The varnish-like resin composition is applied to the support film 43, for example, by using a bar coater. The applied resin composition is heated, for example, at 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 the organic solvent is volatilized from the resin varnish by the heating, and the organic solvent can be reduced or removed.

[0198] The resin-coated film having a resin layer containing the resin composition or the semi-cured product of the resin composition according to the present embodiment is a resin-coated film in which a cured product having low dielectric properties, high thermal conductivity, and excellent adhesion can be suitably obtained.

[0199] The present specification discloses the technology of the various embodiments as described above, and the main technology thereof is summarized as follows.

[0200] The resin composition according to the first aspect of the present invention is a resin composition containing a thermosetting compound (A) and an inorganic filler (B), wherein the thermosetting compound (A) contains at least one radical-polymerizable compound (A1) selected from the group consisting of a polyphenylene ether compound having a reactive unsaturated group, a hydrocarbon compound having a reactive unsaturated group, and a maleimide compound having two or more maleimide groups, the inorganic filler (B) contains a boron nitride filler (B1), and a polydopamine (C) having a functional group (X) that reacts with the radical-polymerizable compound (A1) is attached to the surface of the boron nitride filler (B1).

[0201] The resin composition according to the second aspect of the present invention is the resin composition according to the first aspect of the present invention, wherein the functional group (X) contains at least one selected from the group consisting of an epoxy group, an anilino group, a vinyl group, an acrylic acid group, a methacrylic acid group, an allyl group, a styrene structure, and a maleimide group.

[0202] The resin composition according to the third aspect of the present invention is the resin composition according to the second aspect of the present invention, wherein the polydopamine (C) further has at least one structure selected from the structures represented by the above-mentioned formula (1) and the above-mentioned formula (2).

[0203] The resin composition according to the fourth aspect of the present application is the resin composition according to any one of the first to third aspects of the present application, wherein the polydopamine (C) forms a polydopamine layer on the surface of the boron nitride filler (B1), and the maximum value of the thickness of the polydopamine layer is 0.1 nm or more and 100 nm or less.

[0204] The resin composition according to the fifth aspect of the present application is the resin composition according to any one of the first to fourth aspects of the present application, wherein the cured product of the resin composition has a thermal conductivity of 1 W / mK or more and 50 W / mK or less.

[0205] The resin composition according to the sixth aspect of the present application is the resin composition according to any one of the first to fifth aspects of the present application, wherein the content of the inorganic filler (B) is 40 to 85 parts by mass with respect to 100 parts by mass of the total of the thermosetting compound (A) and the inorganic filler (B).

[0206] 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 of the present application, wherein the content of the boron nitride filler (B1) is 10 to 90 mass% with respect to the inorganic filler (B).

[0207] The resin composition according to the eighth aspect of the present application is the resin composition according to any one of the first to seventh aspects of the present application, further comprising a silane coupling agent.

[0208] The prepreg according to the ninth aspect of the present application comprises: the resin composition according to the first to eighth aspects of the present application or a semi-cured product of the resin composition; and a fibrous base material.

[0209] The resin-coated film according to the tenth aspect of the present application comprises: a resin layer containing the resin composition according to the first to eighth aspects of the present application or a semi-cured product of the resin composition; and a support film.

[0210] The resin-coated metal foil according to the eleventh aspect of the present application comprises: a resin layer containing the resin composition according to the first to eighth aspects of the present application or a semi-cured product of the resin composition; and a metal foil.

[0211] The metal-clad laminate according to the twelfth aspect of the present application comprises: an insulating layer containing a cured product of the resin composition according to the first to eighth aspects of the present application or a cured product of the prepreg according to the ninth aspect of the present application; and a metal foil.

[0212] The wiring board according to the thirteenth aspect of the present application comprises: an insulating layer containing a cured product of the resin composition according to the first to eighth aspects of the present application or a cured product of the prepreg according to the ninth aspect of the present application; and a wiring.

[0213] The present application will be further described below by way of examples, but the scope of the present application is not limited by these examples.

[0214] Examples

[0215] The components used in the preparation of the resin composition in the present example are described.

[0216] (Radical polymerizable compound (A1))

[0217] • Modified polyphenylene ether compound (modified PPE): 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)

[0218] • Hydrocarbon compound: polybutadiene ("Ricon (registered trademark)" manufactured by Cray Valley)

[0219] • Maleimide compound: bismaleimide ("MIR-5000" manufactured by Nippon Shokubai Co., Ltd.)

[0220] (Other thermosetting compound)

[0221] • Curing agent 1: triallyl isocyanurate (TAIC manufactured by Nippon Shokubai Co., Ltd.)

[0222] • Curing agent 2: benzoxazine compound ("P-d" manufactured by Shikoku Chemicals Corporation)

[0223] • Other thermosetting compound: unmodified polyphenylene ether compound ("SA90" manufactured by SABIC Innovative Plastics)

[0224] (Reaction initiator)

[0225] Peroxide initiator: PBP (1,3-bis(butylperoxyisopropyl)benzene; PERBUTYL P manufactured by NOF Corporation)

[0226] (Inorganic filler)

[0227] • Untreated boron nitride filler (BN): h-BN ("SGP" manufactured by Kureha Corporation, average particle diameter: 18 μm)

[0228] • Silica filler: "FB-7SDC" manufactured by Kureha Corporation

[0229] • Alumina filler: "DAW-03AC" manufactured by Kureha Corporation

[0230] • Surface-treated boron nitride filler 1: polydopamine-treated boron nitride filler (without functional group)

[0231] Boron nitride (BN) used h-BN ("SGP" manufactured by Shionogi Corp.). A dopamine solution (concentration: 23 mg / mL) was obtained by adding dopamine hydrochloride to a Tris-HCl solution adjusted to pH 8.5 and stirring. To the obtained dopamine solution was added 4.5 g of the boron nitride. The solution temperature was set to 80°C, and stirring was performed using a magnetic stirrer for 1 hour. Then, a solid was obtained by filtration. The obtained solid was washed with water and dried. Thus, boron nitride particles to which polydopamine was attached were obtained. Next, the obtained particles were subjected to heat treatment using an electric furnace under conditions of 200°C for 24 hours, and a polydopamine-treated boron nitride filler (surface-treated boron nitride filler 1, no functional group) was obtained. The thickness of the polydopamine layer was 2 nm.

[0232] The thickness of the polydopamine layer was measured by X-ray photoelectron spectroscopy (XPS). Specifically, the amounts of B, C, N, and O of the boron nitride were detected from the surface in the depth direction using XPS, and a region in which the amounts of C and O originating from the polydopamine film were confirmed to be increased compared to the untreated boron nitride was defined as the polydopamine layer, and thus the thickness measurement was performed.

[0233] (Boron nitride filler (B1))

[0234] • Surface-treated boron nitride filler 2: polydopamine (C)-treated boron nitride filler (functional group (X): methacrylic group)

[0235] To 1 L of toluene was added 50 mL of methacryl silane coupling agent ("KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.). To the toluene was added 300 g of the surface-treated boron nitride filler 1. The liquid temperature was adjusted to 100°C in a warmed oil bath, and stirring was performed at 500 rpm for 3 hours. Next, the obtained solid was cooled in toluene, and filtration was performed, and then washing was performed using toluene, and drying was performed, and thus the surface-treated boron nitride filler 2 (containing a methacrylic group) was obtained.

[0236] • Surface-treated boron nitride filler 3: polydopamine (C)-treated boron nitride filler (functional group (X): vinyl group)

[0237] The methacryl silane coupling agent ("KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.) was changed to a vinyl silane coupling agent ("KBM-1003" manufactured by Shin-Etsu Chemical Co., Ltd.), and otherwise, the surface-treated boron nitride filler 3 (containing a vinyl group) was obtained by the same method as the surface-treated boron nitride filler 2.

[0238] • Surface-treated boron nitride filler 4: Polydopamine (C)-treated boron nitride filler (functional group (X): styrene structure)

[0239] The methylacryloyl silane coupling agent ("KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.) was changed to a styryl silane coupling agent ("KBM-1403" manufactured by Shin-Etsu Chemical Co., Ltd.), and otherwise, surface-treated boron nitride filler 4 (containing a styrene structure) was obtained by the same method as surface-treated boron nitride filler 2.

[0240] • Surface-treated boron nitride filler 5: Polydopamine (C)-treated boron nitride filler (functional group (X): acrylic group)

[0241] The methylacryloyl silane coupling agent ("KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.) was changed to an acryloyl silane coupling agent ("KBM-5103" manufactured by Shin-Etsu Chemical Co., Ltd.), and otherwise, surface-treated boron nitride filler 5 (containing an acrylic group) was obtained by the same method as surface-treated boron nitride filler 2.

[0242] • Surface-treated boron nitride filler 6: Polydopamine (C)-treated boron nitride filler (functional group (X): methacrylic group)

[0243] The time for stirring with a magnetic stirrer after adding boron nitride to the dopamine solution was changed from 1 hour to 4 hours, and otherwise, surface-treated boron nitride filler 6 (containing a methacrylic group, thickness of dopamine layer 20 nm) was obtained by the same method as surface-treated boron nitride filler 2.

[0244] • Surface-treated boron nitride filler 7: Polydopamine (C)-treated boron nitride filler (functional group (X): methacrylic group)

[0245] The time for stirring with a magnetic stirrer after adding boron nitride to the dopamine solution was changed from 1 hour to 12 hours, and otherwise, surface-treated boron nitride filler 7 (containing a methacrylic group, thickness of dopamine layer 100 nm) was obtained by the same method as surface-treated boron nitride filler 2.

[0246] • Surface-treated boron nitride filler 8: Polydopamine (C)-treated boron nitride filler (acylation)

[0247] Example 1 2.0 g of the surface-treated boron nitride filler 1 was added to 20 ml of deionized water, and 0.1 g of DMAP was added as a catalyst and dissolved. Next, 2 ml of methacrylic anhydride was added as an acylating agent, and a mixed solution was obtained. The temperature of the mixed solution was set to 25°C, and stirring was performed using a magnetic stirrer for 24 hours. Then, a solid was obtained by filtering the mixed solution. The obtained solid was washed with toluene and dried. Thus, the surface-treated boron nitride filler 8 (acylated, containing a methacrylic acid group, thickness of the polydopamine layer: 2 nm) (boron nitride filler having a polydopamine having a structure represented by Formula (1) attached thereto) was obtained.

[0248] (Silane coupling agent)

[0249] • Methacryl silane coupling agent ("KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.)

[0250] [Examples 1 to 20 and Comparative Examples 1 to 4]

[0251] (Preparation method)

[0252] First, each of the organic resin components except for the inorganic filler was added to toluene as a solvent and mixed so that the solid content concentration became about 40 to 80 mass% at the composition (mass parts) described in Tables 1 and 2. The mixture was stirred for 60 minutes. Then, each of the inorganic fillers and the coupling agent was added to the obtained liquid at the ratio (mass parts) described in Tables 1 and 2, and the inorganic filler was dispersed with a bead mill. By this operation, a varnish-like resin composition (varnish) was obtained.

[0253] Next, the evaluation substrate (cured product of the prepreg) was obtained as follows.

[0254] The obtained varnish was impregnated into a fibrous base material (glass cloth: #1078 type, L glass, manufactured by Asahi Kasei Corp.), and heated and dried at 110°C for 3 minutes, whereby a prepreg was produced. Then, each of the obtained prepregs was taken one sheet, two sheets were overlapped, or four sheets were overlapped, and the copper foil ("FV-WS" manufactured by Furukawa Electric Co., Ltd., copper foil thickness: 18 μm) was attached to both side surfaces of the obtained board, and heated to a temperature of 200°C at a temperature increase rate of 4°C / minute, and heated and pressurized at 200°C, 120 minutes, and a pressure of 3 MPa, whereby copper-clad laminated boards of three kinds of board thicknesses were produced.

[0255] The copper-clad laminate prepared as described above was used as an evaluation substrate, and evaluation was performed by the method shown below. Note that, in the measurement of thermal conductivity described later, a board from which the copper foil was removed was used from the cured product of one prepreg and the copper-clad laminate in which two prepregs were overlaid, and a board from which the copper foil was removed was used from the copper-clad laminate in which four prepregs were overlaid (cured product of prepreg), and in the evaluation test of dielectric properties (relative dielectric constant), a board from which the copper foil was removed was used from the copper-clad laminate in which four prepregs were overlaid (cured product of prepreg).

[0256] [Thermal conductivity]

[0257] The thermal conductivity of the obtained evaluation substrate (cured product of prepreg) was measured by the method according to ASTM D5470. Specifically, the thermal resistance and thickness of the obtained evaluation substrate (cured product of one prepreg, cured product of two prepregs overlaid, cured product of four prepregs overlaid) were measured using a thermal property evaluation device (T3Ster DynTIM Tester manufactured by Mentor Graphics), and the measured values were plotted in a graph, approximated by a straight line, and the thermal conductivity was calculated from the increase in thermal resistance and thickness. The pass standard for thermal conductivity in this example was 1.0 W / m-K or more.

[0258] [Dielectric properties (relative dielectric constant)]

[0259] The dielectric loss factor (Df) 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 standard in this example was Df < 0.003.

[0260] [Copper foil peel strength]

[0261] First, in order to perform the peel strength (copper foil peel) test, a copper-clad laminate (CCL) was produced using the prepreg of each example and comparative example. Specifically, four prepregs were overlaid, and a copper foil ("FV-WS" manufactured by Furukawa Electric Co., Ltd.) having a thickness of 18 μm was attached to both side surfaces, and the copper-clad laminate (CCL) (evaluation substrate) in which the copper foil having a thickness of 510 μm was adhered to both side surfaces was obtained by heating and pressing under vacuum conditions at a temperature of 200°C and a pressure of 3 MPa for 120 minutes.

[0262] Then, using the obtained CCL, the peel strength at the time of peeling the copper foil from the insulating layer was measured in accordance with JIS C 6481. A pattern having a width of 10 mm and a length of 100 mm was formed, and peeling was performed at a speed of 50 mm / minute using a tensile testing machine, and the peel strength at that time was measured. The unit of measurement was kN / m. The pass standard in this example was 0.40 kN / m or more.

[0263] The results of the above evaluations are shown in Table 1 and Table 2.

[0264]

[0265]

[0266] (Investigation)

[0267] As is clear from Table 1 and Table 2, it was confirmed that the examples in which the resin composition of the present application was used all resulted in cured products that had low dielectric properties, high thermal conductivity, and excellent adhesion.

[0268] On the other hand, as shown in Table 2, in the sample of Comparative Example 1 that did not contain the radically polymerizable compound (A1), sufficient dielectric properties and adhesion were not obtained. Furthermore, in the samples of Comparative Examples 2 and 3 in which a boron nitride filler that had not been surface-treated with a polydopamine film was used as the inorganic filler, results of poor adhesion were obtained. From the comparison of Comparative Examples 2 and 3, it was also confirmed that if the content of the boron nitride filler was increased, the thermal conductivity improved, but the adhesion was poorer. Furthermore, in Comparative Example 4 in which a boron nitride filler that had been surface-treated with polydopamine but did not have functional groups (X) was used, sufficient adhesion was not obtained.

[0269] This application is based on Japanese Patent Application No. 2023-140937 filed on August 31, 2023, the contents of which are incorporated herein.

[0270] In order to describe the present application, the present application has been adequately and sufficiently described above by embodiments with reference to specific examples and drawings, but it should be recognized that the above-described embodiments can be easily changed and / or improved by those skilled in the art. Therefore, the changed or improved embodiments implemented by those skilled in the art can be interpreted as being included in the scope of protection of the claims as long as they are within the scope of protection of the claims recited in the claims.

[0271] Industrial applicability

[0272] 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 in that... contain: Thermosetting compound (A) and inorganic filler (B), wherein, The thermosetting compound (A) comprises at least one radical polymerizable compound (A1) selected from the group consisting of polyphenylene ether compounds having reactive unsaturated groups, hydrocarbon compounds having reactive unsaturated groups, and maleimide compounds having two or more maleimide groups. The inorganic filler (B) includes boron nitride filler (B1). Polydopamine (C) is attached to the surface of the boron nitride filler (B1), which has a functional group (X) that reacts with the free radical polymerizable compound (A1).

2. The resin composition according to claim 1, characterized in that, The functional group (X) comprises at least one selected from the group consisting of epoxy, phenylamino, vinyl, acrylic, methacrylate, allyl, styrene, and maleimide.

3. The resin composition according to claim 2, characterized in that, The polydopamine (C) also has at least one structure selected from the structures shown in formula (1) and formula (2) below. 。 4. The resin composition according to claim 1, characterized in that, The polydopamine (C) forms a polydopamine layer on the surface of the boron nitride filler (B1). The maximum thickness of the dopamine layer is greater than 0.1 nm and less than 100 nm.

5. The resin composition according to claim 1, characterized in that, The cured resin composition has a thermal conductivity of 1 W / mK or more and 50 W / mK or less.

6. The resin composition according to claim 1, characterized in that, The content of inorganic filler (B) is 40 to 85 parts by weight relative to a total of 100 parts by weight of the thermosetting compound (A) and the inorganic filler (B).

7. The resin composition according to claim 1, characterized in that, The content of the boron nitride filler (B1) is 10 to 90% by mass relative to the inorganic filler (B).

8. The resin composition according to claim 1, characterized in that... It also contains: Silane coupling agent.

9. A prepreg, characterized in that... include: The resin composition or the semi-cured product of the resin composition according to any one of claims 1 to 8; as well as Fiber-based substrate.

10. A resin-coated membrane, characterized in that... include: A resin layer comprising the resin composition of any one of claims 1 to 8 or a semi-cured product of the resin composition; as well as Support membrane.

11. A resin-coated metal foil, characterized in that... include: A resin layer comprising the resin composition of any one of claims 1 to 8 or a semi-cured product of the resin composition; as well as Metal foil.

12. A metal foil-coated laminate, characterized in that... include: An insulating layer comprising a cured product of the resin composition according to any one of claims 1 to 8; as well as Metal foil.

13. A wiring board, characterized in that... include: An insulating layer comprising a cured product of the resin composition according to any one of claims 1 to 8; as well as wiring.

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

15. A wiring board, characterized in that... include: An insulating layer comprising the cured prepreg of claim 9; as well as wiring.

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