Resin composition, prepreg, resin-bearing film, resin-bearing metal foil, metal-clad laminate sheet, 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), wherein: the thermosetting compound (A) contains at least one radically polymerizable compound (A1) selected from the group consisting of polyphenylene ether compounds having a reactive unsaturated group, hydrocarbon compounds having a reactive unsaturated group, and maleimide compounds 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

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

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

[0002] As the amount of information processed increases in various electronic devices, advances in packaging technologies, such as higher integration of semiconductor devices, higher density wiring, and multi-layering, are being made. Furthermore, wiring boards used in various electronic devices are required to be high-frequency compatible, such as millimeter-wave radar boards for automotive applications. To increase the signal transmission speed, wiring boards used in various electronic devices are required to reduce loss during signal transmission, and this is particularly true for high-frequency compatible wiring boards. To meet this requirement, the substrate material for forming the substrate of the wiring board used in various electronic devices is required to have a low dielectric constant and dielectric loss tangent.

[0003] As such a substrate material, for example, a PPE-containing resin composition containing PPE (polyphenylene ether), a crosslinkable curable compound, and a phosphaphenanthrene derivative has been reported to have excellent low dielectric properties (Patent Document 1).

[0004] On the other hand, electronic materials used in PA (power amplifier) ​​substrates for base stations, etc., are required to have not only low dielectric properties but also high thermal conductivity. One method for improving the thermal conductivity of resin compositions has been reported to date, which uses boron nitride as an inorganic filler (Patent Document 2).

[0005] The boron nitride filler described in Patent Document 2 does indeed improve the thermal conductivity of resin compositions. However, when using resin compositions as molding materials such as substrate materials, even better adhesion is required. In this regard, it has been found that boron nitride does not have sufficient adhesion to resins. Poor adhesion between the inorganic filler and the resin makes the cured resin composition more susceptible to fracture, and when a resin composition containing the inorganic filler is used as a substrate material such as a metal-clad laminate, it also has poor adhesion to metal foil. The technology described in Patent Document 2 uses an aldehyde compound as a surface modifier for the inorganic filler to increase thermal conductivity, but the adhesion problem described above remains unresolved.

[0006] JP 2015-67700 A JP 2020-73422 A

[0007] The present invention has been made in view of the above circumstances, and aims to provide a resin composition that can give a cured product having low dielectric properties, high thermal conductivity, and excellent adhesion. It is also an object of the present invention to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using the resin composition.

[0008] As a result of extensive investigations, the present inventors have found that the above object can be achieved by the following constitution, and have achieved the present invention through further investigations.

[0009] A resin composition according to one aspect of the present invention is a resin composition comprising a thermosetting compound (A) and an inorganic filler (B), wherein the thermosetting compound (A) comprises at least one radically polymerizable compound (A1) selected from the group consisting of polyphenylene ether compounds having a reactive unsaturated group, hydrocarbon compounds having a reactive unsaturated group, and maleimide compounds having two or more maleimide groups; the inorganic filler (B) comprises a boron nitride filler (B1); and polydopamine (C) having a functional group (X) reactive with the radically polymerizable compound (A1) is attached to the surface of the boron nitride filler (B1).

[0010] Fig. 1 is a schematic cross-sectional view showing an example of a prepreg according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate according to an embodiment of the present invention. Fig. 3 is a schematic cross-sectional view showing an example of a wiring board according to an embodiment of the present invention. Fig. 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil according to an embodiment of the present invention. Fig. 5 is a schematic cross-sectional view showing an example of a resin-coated film according to an embodiment of the present invention.

[0011] Hereinafter, embodiments of the present invention will be specifically described, but the present invention is not limited to these.

[0012] [Resin Composition] The resin composition according to an embodiment of the present invention is a resin composition comprising a thermosetting compound (A) and an inorganic filler (B). The thermosetting compound (A) comprises at least one radically 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) also comprises a boron nitride filler (B1), and a polydopamine (C) having a functional group (X) reactive with the radically polymerizable compound (A1) is attached to the surface of the boron nitride filler (B1).

[0013] The above-mentioned configuration provides a resin composition that can give a cured product having low dielectric properties, high thermal conductivity, and excellent adhesion. Furthermore, the present invention also provides 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.

[0014] First, each component of the resin composition of the present embodiment will be described.

[0015] (Thermosetting Compound (A)) The thermosetting resin compound (A) of this embodiment is a thermosetting compound containing a radically polymerizable compound (A1). The radically polymerizable compound (A1) used in this embodiment is a compound having radical polymerizability, and examples thereof include compounds having a reactive unsaturated group and compounds having a maleimide group. More specific examples thereof include polyphenylene ether compounds, cyanate ester compounds, active ester compounds, and compounds having an unsaturated group. Examples of the compound having an unsaturated group include acrylic compounds, methacrylic compounds, vinyl compounds, allyl compounds, propenyl compounds, maleimide compounds, and hydrocarbon compounds having an unsaturated double bond.

[0016] Among these, the thermosetting resin compound (A) of this embodiment contains at least one radically 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. By containing these radically polymerizable compounds (A1), it is possible to obtain a resin composition having excellent low dielectric properties in the cured product. Each of these compounds will be described in more detail below.

[0017] Polyphenylene Ether Compound The polyphenylene ether compound that can be used in this embodiment is not particularly limited as long as it is a polyphenylene ether compound having a reactive unsaturated group in the molecule. In this specification, the term "reactive unsaturated group" refers to, for example, a group having an unsaturated double bond or the like. Specific examples of polyphenylene ether compounds having a reactive unsaturated group include polyphenylene ether compounds having a group represented by the following formula (3) or formula (4). It is believed that the inclusion of such a modified polyphenylene ether compound results in a resin composition that can give a cured product with low dielectric properties and high heat resistance.

[0018]

[0019] In formula (3), s represents an integer of 0 to 10. Z represents an arylene group.１ ~R ３ are independent of each other. That is, R １ ~R ３ may be the same group or different groups. １ ~R ３ represents a hydrogen atom or an alkyl group.

[0020] In addition, in formula (3), when s is 0, this indicates that Z is directly bonded to the end of the polyphenylene ether.

[0021] The arylene group represented by Z is not particularly limited. Examples of the arylene group include monocyclic aromatic groups such as a phenylene group, and polycyclic aromatic groups in which the aromatic ring is not monocyclic but is a polycyclic aromatic ring such as a naphthalene ring. The arylene group also includes derivatives 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. The alkyl group is not particularly limited, and is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0022]

[0023] In formula (4), R ４ represents a hydrogen atom or an alkyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0024] Preferred specific examples of the substituent represented by formula (3) include, for example, a substituent containing a vinylbenzyl group. Examples of the substituent containing a vinylbenzyl group include, for example, a substituent represented by formula (5) below. Furthermore, examples of the substituent represented by formula (4) include an acrylate group and a methacrylate group.

[0025]

[0026] More specific examples of the substituent include vinylbenzyl groups (ethenylbenzyl groups) such as p-ethenylbenzyl and m-ethenylbenzyl groups, vinylphenyl groups, acrylate groups, and methacrylate groups.

[0027] The polyphenylene ether compound has a polyphenylene ether chain in the molecule, and preferably has, for example, a repeating unit represented by the following formula (6) in the molecule.

[0028]

[0029] In formula (6), t represents 1 to 50. ５ ~R ８ are independent of each other. That is, R ５ ~R ８ may be the same group or different groups. ５ ~R ８ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0030] R ５ ~R ８ Specific examples of the functional groups mentioned in the above include the following:

[0031] The alkyl group is not particularly limited, but is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0032] The alkenyl group is not particularly limited, but is preferably an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples include a vinyl group, an allyl group, and a 3-butenyl group.

[0033] The alkynyl group is not particularly limited, but is preferably an alkynyl group having 2 to 18 carbon atoms, and more preferably an alkynyl group having 2 to 10 carbon atoms. Specific examples include an ethynyl group and a prop-2-yn-1-yl group (propargyl group).

[0034] The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, but for example, an alkylcarbonyl group having 2 to 18 carbon atoms is preferred, and an alkylcarbonyl group having 2 to 10 carbon atoms is more preferred. Specific examples include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pivaloyl group, a hexanoyl group, an octanoyl group, and a cyclohexylcarbonyl group.

[0035] The alkenylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkenyl group, but for example, an alkenylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkenylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include an acryloyl group, a methacryloyl group, and a crotonoyl group.

[0036] The alkynylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkynyl group, but for example, an alkynylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkynylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include a propioloyl group.

[0037] The weight-average molecular weight (Mw) of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 500 to 5,000, more preferably 800 to 4,000, and even more preferably 1,000 to 3,000. The weight-average molecular weight may be measured by a general molecular weight measurement method, specifically, a value measured using gel permeation chromatography (GPC), etc. Furthermore, when the polyphenylene ether compound has a repeating unit represented by the formula (6) in the molecule, t is preferably a value such that the weight-average molecular weight of the polyphenylene ether compound falls within this range. Specifically, t is preferably 1 to 50.

[0038] When the weight-average molecular weight of the polyphenylene ether compound is within this range, the compound has the excellent low dielectric properties of polyphenylene ether, and the cured product not only has excellent heat resistance but also has excellent moldability. This is believed to be due to the following reasons. When the weight-average molecular weight of a typical polyphenylene ether is within this range, the compound has a relatively low molecular weight, which tends to reduce the heat resistance of the cured product. In this regard, the polyphenylene ether compound according to this embodiment has one or more unsaturated double bonds at its terminals, which is believed to result in a cured product with sufficiently high heat resistance. Furthermore, when the weight-average molecular weight of the polyphenylene ether compound is within this range, the compound has a relatively low molecular weight, which is believed to result in excellent moldability. Therefore, it is believed that such a polyphenylene ether compound not only has excellent heat resistance but also has excellent moldability.

[0039] In the polyphenylene ether compound, the average number of the substituents (number of terminal functional groups) at the molecular terminals per molecule of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.5 to 3. If the number of terminal functional groups is too small, it tends to be difficult to obtain sufficient heat resistance of the cured product. On the other hand, if the number of terminal functional groups is too large, the reactivity becomes too high, which may cause problems such as reduced storage stability of the resin composition or reduced fluidity of the resin composition.

[0040] The number of terminal functional groups of a polyphenylene ether compound may be, for example, a numerical value representing the average number of the substituents per molecule of all modified polyphenylene ether compounds present in 1 mole of the polyphenylene ether compound. The number of terminal functional groups can be measured, for example, by measuring the number of hydroxyl groups remaining in the obtained modified polyphenylene ether compound and calculating the difference from the number of hydroxyl groups in the polyphenylene ether before modification. This difference from the number of hydroxyl groups in the polyphenylene ether before modification is the number of terminal functional groups. The number of hydroxyl groups remaining in the modified polyphenylene ether compound can be measured by adding a quaternary ammonium salt (tetraethylammonium hydroxide) that associates with hydroxyl groups to a solution of the modified polyphenylene ether compound and measuring the UV absorbance of the resulting mixed solution.

[0041] Examples of the polyphenylene ether compound of the present embodiment include a modified polyphenylene ether compound represented by the following formula (7) and a modified polyphenylene ether compound represented by the following formula (8). Furthermore, as the polyphenylene ether compound of the present embodiment, these modified polyphenylene ether compounds may be used alone, or these two types of modified polyphenylene ether compounds may be used in combination.

[0042]

[0043]

[0044] In formula (7) and formula (8), R ９ ~R １６ and R １７ ~R ２４ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. １ and X ２ each independently represents a substituent having a carbon-carbon unsaturated double bond. A and B represent repeating units represented by the following formula (9) and formula (10), respectively. In addition, in formula (8), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms.

[0045]

[0046]

[0047] In formula (9) and formula (10), m and n each represent an integer of 0 to 20. ２５ ~R ２８ and R ２９ ~R ３２ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0048] 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 satisfy the above-mentioned constitution. Specifically, in the formulas (7) and (8), R ９ ~R １６ and R １７ ~R ２４ As described above, each of R is independent. ９ ~R １６ and R １７ ~R ２４ may be the same group or different groups. ９ ~R １６ and R １７ ~R ２４represents 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 which a hydrogen atom and an alkyl group are preferred.

[0049] In formula (9) and formula (10), m and n each preferably represent a value of 0 to 20, as described above. Furthermore, it is preferable that m and n represent a numerical value such that the sum of m and n is 1 to 30. Therefore, it is more preferable that m represents a value of 0 to 20, n represents a value of 0 to 20, and the sum of m and n represents a value of 1 to 30. Furthermore, R ２５ ~R ２８ and R ２９ ~R ３２ are independent of each other. That is, R ２５ ~R ２８ and R ２９ ~R ３２ may be the same group or different groups. ２５ ~R ２８ and R ２９ ~R ３２ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0050] R ９ ~R ３２ is R in the above formula (6). ５ ~R ８ is the same as

[0051] In the formula (8), Y is, as described above, a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms. Examples of Y include a group represented by the following formula (11).

[0052]

[0053] In the formula (11), R ３３ and R ３４are each independently a hydrogen atom or an alkyl group. Examples of the alkyl group include a methyl group. Examples of the group represented by formula (11) include a methylene group, a methylmethylene group, and a dimethylmethylene group, and among these, a dimethylmethylene group is preferred.

[0054] In the formula (7) and the formula (8), X １ and X ２ are each independently a substituent having a carbon-carbon unsaturated double bond. １ and X ２ There are no particular limitations on the substituent X as long as it is a substituent having a carbon-carbon unsaturated double bond. １ and X ２ Examples of the substituents include the substituents represented by the formula (3) and the substituents represented by the formula (4). In the modified polyphenylene ether compound represented by the formula (7) and the modified polyphenylene ether compound represented by the formula (8), X １ and X ２ may be the same substituent or different substituents.

[0055] More specific examples of the modified polyphenylene ether compound represented by the formula (7) include modified polyphenylene ether compounds represented by the following formula (12).

[0056]

[0057] More specific examples of the modified polyphenylene ether compound represented by formula (8) include a modified polyphenylene ether compound represented by formula (13) below and a modified polyphenylene ether compound represented by formula (14) below.

[0058]

[0059]

[0060] In the above formulas (12) to (14), m and n are the same as m and n in the above formulas (9) and (10).１ ~R ３ , p and Z are R in the above formula (3), １ ~R ３ , s, and Z. In the formulas (13) and (14), Y is the same as Y in the formula (8). In the formula (14), R ４ is R in the above formula (4). ４ is the same as

[0061] It is believed that by using the modified polyphenylene ether compound as described above, it is possible to improve the high Tg and adhesion while maintaining low dielectric properties such as low dielectric loss tangent and excellent heat resistance.

[0062] The modified polyphenylene ether compounds may be used singly or in combination of two or more.

[0063] The polyphenylene ether compound used in the resin composition of this embodiment can be synthesized by a known method, or a commercially available product can be used. Examples of commercially available products include "OPE-2st 1200" and "OPE-2st 2200" manufactured by Mitsubishi Gas Chemical Company, Inc., and "SA9000" manufactured by SABIC Innovative Plastics.

[0064] Hydrocarbon-Based Compound Having a Reactive Unsaturated Group The hydrocarbon-based compound that can be used in this embodiment is not particularly limited as long as it is a hydrocarbon-based compound having a reactive unsaturated group in the molecule. Preferred examples of the hydrocarbon-based compound include hydrocarbon resins such as polyfunctional vinyl aromatic polymers, cyclic polyolefin resins, and vinyl aromatic compound-conjugated diene compound copolymers.

[0065] The polyfunctional vinyl aromatic polymer is preferably a polymer containing at least a polyfunctional vinyl aromatic compound and / or a derivative thereof polymerized therein, and is not particularly limited as long as it is a polymer containing a structure derived from a polyfunctional vinyl aromatic compound and / or a derivative thereof, and may be a polymer containing one or more polyfunctional vinyl aromatic compounds and / or a structure derived from a derivative thereof.

[0066] In addition to the structural units of the polyfunctional vinyl aromatic compound and / or its derivatives, the copolymer may further contain one or more structural units derived from a reactive monomer. The reactive monomer is not particularly limited, but may be, for example, a polyfunctional vinyl aromatic copolymer having structural units derived from a monovinyl aromatic compound such as styrene.

[0067] More specifically, examples of the polyfunctional vinyl compound include a polyfunctional vinyl compound having two or more vinyl groups in the molecule, such as divinylbenzene, divinylnaphthalene, divinylbiphenyl, and polybutadiene.

[0068] Maleimide Compounds The maleimide compounds that can be used in this embodiment are not particularly limited as long as they have two or more maleimide groups in the molecule. Specific examples of the maleimide compounds include polyfunctional maleimide compounds having two or more maleimide groups in the molecule, and modified maleimide compounds thereof. Examples of the modified maleimide compounds include modified maleimide compounds in which a portion of the molecule is modified with an amine compound, modified maleimide compounds in which a portion of the molecule is modified with a silicone compound, and modified maleimide compounds in which a portion of the molecule is modified with both an amine compound and a silicone compound.

[0069] More specific examples include maleimide compounds having two or more N-substituted maleimide groups in one molecule, maleimide compounds having an indane structure, maleimide compounds having at least one group selected from an alkyl group having 6 or more carbon atoms and an alkylene group having 6 or more carbon atoms, and maleimide compounds having a benzene ring in the molecule.

[0070] The maleimide compound used in this embodiment may be a commercially available product, and examples thereof include MIR-3000 and MIR-5000 manufactured by Nippon Kayaku Co., Ltd.; BMI-4000, BMI-2300, BMI-TMH, BMI-4000, and BMI-5100 manufactured by Daiwa Kasei Kogyo Co., Ltd.; and BMI-689, BMI-1500, BMI-3000J, and BMI-5000 manufactured by Designer Molecules Inc.

[0071] Other Thermosetting Compounds (Curing Agents) The resin composition of the present embodiment may further contain a thermosetting compound other than the radically polymerizable compound (A1) as described above. In this case, the thermosetting compound is preferably a thermosetting compound that acts as a curing agent capable of reacting with the radically polymerizable compound as described above.

[0072] Specifically, among thermosetting compounds, for example, phenolic resins, benzoxazine compounds, styrene compounds, styrene derivatives, compounds having an acryloyl group in the molecule, compounds having a methacryloyl group in the molecule, compounds having a vinyl group in the molecule, compounds having an allyl group in the molecule, compounds having an acenaphthylene structure in the molecule, isocyanurate compounds having an isocyanurate group in the molecule, monomaleimide compounds, etc. are preferably exemplified as the curing agent. These can be used alone, or the above-mentioned radical polymerizable compound (A1) and two or more curing agents can be used in combination.

[0073] As the benzoxazine compound, for example, a benzoxazine compound represented by the following general formula (15) can be used.

[0074]

[0075] 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 l represents an integer of 0 to 4.

[0076] Commercially available products include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Corporation; "P-d", "F-a", and "ALP-d" manufactured by Shikoku Chemicals Corporation; and "HFB2006M" manufactured by Showa Polymer Co., Ltd.

[0077] The styrene compound is not particularly limited as long as it has a styrene skeleton in the molecule, but preferred examples include resin compounds whose terminals are modified with a styrene skeleton.

[0078] Examples of the styrene derivatives include bromostyrene and dibromostyrene.

[0079] The compound having an acryloyl group in the molecule is an acrylate compound. Examples of the acrylate compound include a monofunctional acrylate compound having one acryloyl group in the molecule and a polyfunctional acrylate compound having two or more acryloyl groups in the molecule. Examples of the monofunctional acrylate compound include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. Examples of the polyfunctional acrylate compound include tricyclodecane dimethanol diacrylate.

[0080] The compound having a methacryloyl group in the molecule is a methacrylate compound. Examples of the methacrylate compound include a monofunctional methacrylate compound having one methacryloyl group in the molecule and a polyfunctional methacrylate compound having two or more methacryloyl groups in the molecule. Examples of the monofunctional methacrylate compound include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Examples of the polyfunctional methacrylate compound include tricyclodecane dimethanol dimethacrylate.

[0081] The compound having a vinyl group in the molecule is a vinyl compound. Examples of the vinyl compound include a monofunctional vinyl compound (monovinyl compound) having one vinyl group in the molecule.

[0082] The compound having an allyl group in the molecule is an allyl compound. Examples of the allyl compound include a monofunctional allyl compound having one allyl group in the molecule and a polyfunctional allyl compound having two or more allyl groups in the molecule. Examples of the polyfunctional allyl compound include diallyl phthalate (DAP).

[0083] The compound having an acenaphthylene structure in the molecule is an acenaphthylene compound. Examples of the acenaphthylene compound include acenaphthylene, alkylacenaphthylenes, halogenated acenaphthylenes, and phenylacenaphthylenes. Examples of the alkylacenaphthylenes include 1-methylacenaphthylene, 3-methylacenaphthylene, 4-methylacenaphthylene, 5-methylacenaphthylene, 1-ethylacenaphthylene, 3-ethylacenaphthylene, 4-ethylacenaphthylene, and 5-ethylacenaphthylene. Examples of the halogenated acenaphthylenes include 1-chloroacenaphthylene, 3-chloroacenaphthylene, 4-chloroacenaphthylene, 5-chloroacenaphthylene, 1-bromoacenaphthylene, 3-bromoacenaphthylene, 4-bromoacenaphthylene, and 5-bromoacenaphthylene. Examples of the phenylacenaphthylenes include 1-phenylacenaphthylene, 3-phenylacenaphthylene, 4-phenylacenaphthylene, and 5-phenylacenaphthylene. The acenaphthylene compound may be a monofunctional acenaphthylene compound having one acenaphthylene structure in the molecule, as described above, or a polyfunctional acenaphthylene compound having two or more acenaphthylene structures in the molecule.

[0084] The compound having an isocyanurate group in the molecule is an isocyanurate compound. Examples of the isocyanurate compound include compounds further having an alkenyl group in the molecule (alkenyl isocyanurate compounds), such as triallyl isocyanurate (TAIC).

[0085] Among the above, for example, benzoxazine compounds, isocyanurate compounds having an isocyanurate group in the molecule, N-phenylmaleimide, and resin compounds whose terminals are modified with a styrene skeleton are preferably used.

[0086] The thermosetting compounds used as the curing agent as described above may be used either alone or in combination of two or more.

[0087] In the resin composition of this embodiment, the content of the thermosetting compound (A) is preferably 15 to 60 parts by mass, and more preferably 20 to 55 parts by mass, per 100 parts by mass of the total of the thermosetting compound (A) and the inorganic filler (B). When the content of the thermosetting compound (A) is within the above range, it is believed that a resin composition that can give a cured product with low dielectric properties and high heat resistance can be more reliably obtained.

[0088] When the resin composition of this embodiment contains a thermosetting compound (which acts as a curing agent) in addition to the radically polymerizable compound (A1), the content ratio of the radically polymerizable compound (A1):other thermosetting compound is preferably about 95:5 to 50:50 by mass. If the content ratio is within this range, the resin composition will have superior heat resistance in the cured product. This is thought to be because the curing reaction between the resin component of this embodiment and the curing agent proceeds smoothly.

[0089] (Inorganic Filler (B)) Boron Nitride Filler (B1) The resin composition according to this embodiment further contains an inorganic filler (B) containing a boron nitride filler (B1). The boron nitride filler is not particularly limited as long as it can be used as the inorganic filler contained in the resin composition. In this embodiment, hexagonal boron nitride (h-BN) having a graphite-type layer structure, diamond-type cubic boron nitride (c-BN), amorphous boron nitride (a-BN), and the like can be used as the boron nitride filler (B1). h-BN is particularly useful because it can be synthesized relatively easily and has excellent thermal conductivity, electrical insulation, chemical stability, and heat resistance. In addition, boron nitride particles can be used as the boron nitride filler (B1). The boron nitride particles are usually white. The shape of the boron nitride particles is not particularly limited. The shape of the boron nitride particles may be, for example, scale-like, spherical, oval-spherical, rod-like, or the like.

[0090] The average particle size of the boron nitride particles is not particularly limited. The average particle size of the boron nitride particles may 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 this embodiment, the average particle size of the boron nitride particles refers to the median diameter. The median diameter refers to the particle size (d50) when the cumulative volume in the volume-based particle size distribution is equal to 50%. The volume-based particle size distribution is measured, for example, using a laser diffraction measurement device.

[0091] In this embodiment, polydopamine (C) having a functional group (X) reactive with the radically polymerizable compound (A1) is attached to the surface of the boron nitride filler (B1). The polydopamine (C) may cover at least a portion of the surface of the boron nitride filler (B1). In this case, the polydopamine (C) may cover the entire surface of the boron nitride filler (B1), or may cover only a portion of the surface of the boron nitride filler (B1).

[0092] Polydopamine Polydopamine is a polymer of dopamine and may have, for example, a repeating unit represented by the following formula (16): In the following formula (16), the indoline skeleton portion may be an indole skeleton.

[0093]

[0094] In the above composition formula (16), n is an integer of 1 or more, particularly 2 or more.

[0095] As shown in the above formula (16), polydopamine may have an indoline skeleton and / or an indole skeleton. However, polydopamine may include those that are not completely cyclized. That is, polydopamine may contain a mixture of primary and secondary amines. Furthermore, in formula (16), the 5,6-dihydroxyindoline structure may contain any of the quinone structures shown in the following structural formulas:

[0096]

[0097] The polydopamine (C) of this embodiment is obtained by introducing a functional group (X) into such polydopamine. That is, the polydopamine (C) of this embodiment has a functional group (X) that reacts with the radical polymerizable compound (A1). By attaching the polydopamine (C) having the functional group (X) that reacts with the radical polymerizable compound (A1) to the boron nitride filler (B1), the adhesion between the radical polymerizable compound (A1) and the boron nitride filler (B1) is improved. As a result, peeling between the inorganic filler (B) and the thermosetting resin (A) can be suppressed, and the adhesion between the resin composition and a metal foil or the like is improved. Furthermore, the functional group (X) derived from dopamine in the polydopamine (C) may be partially modified.

[0098] The polydopamine (C) may be in the form of a thin film on the surface of the boron nitride filler (B1). The thickness of the polydopamine (C) thin film is, for example, 0.1 nm to 300 nm, more preferably 0.1 nm to 100 nm. The polydopamine (C) thin film may cover at least a portion of the surface of the boron nitride filler (B1), or may cover the entire surface of the boron nitride filler (B1).

[0099] The functional group (X) is not particularly limited as long as it reacts with the radical polymerizable compound (A1) and the thermosetting compound (which acts as a curing agent).

[0100] For example, the functional group (X) of the polydopamine (C) preferably includes at least one selected from the group consisting of an epoxy group, a phenylamino group, a vinyl group, an acrylic group, a methacrylic group, an allyl group, a styrene structure, and a maleimide group.

[0101] In this specification, the term "styrene structure" refers to a structure represented by the following formula (S).

[0102]

[0103] - Manufacturing method for boron nitride filler (B1) having attached thereto polydopamine (C) having a functional group (X) reactive with radically polymerizable compound (A1) The boron nitride filler (B1) of this embodiment can be obtained by, for example, attaching polydopamine to the surface of a boron nitride filler and then introducing a functional group (X) into the attached polydopamine, thereby obtaining a boron nitride filler (B1) having attached thereto a polydopamine (C) having a functional group (X). Note that, before introducing the functional group (X) into the polydopamine, the boron nitride filler having attached thereto a polydopamine may be heat-treated.

[0104] There are no particular limitations on the method for attaching polydopamine to the surface of the boron nitride filler. Polydopamine can be attached to the surface of the boron nitride filler by contacting the boron nitride filler with a dopamine solution and oxidatively polymerizing the dopamine.

[0105] The dopamine solution can be obtained, for example, by adding dopamine hydrochloride to a Tris-HCl solution whose pH has been adjusted to 8.5 and stirring the mixture. The concentration of the dopamine solution is not particularly limited and may be, for example, in the range of 0.01 mg / mL to 30 mg / mL. The pH of the dopamine solution is in the range of 6 to 11, and may be in the range of 8 to 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 during oxidative polymerization is, for example, 10°C to 100°C. The polymerization time is, for example, 1 hour to 48 hours.

[0106] Furthermore, when at least a portion of the surface of the boron nitride filler is coated to form a polydopamine layer (a thin polydopamine film), the maximum thickness of the polydopamine layer is preferably, for example, 0.1 nm or more and 100 nm or less. This has the advantage of improving adhesion to the thermosetting resin while maintaining the low dielectric tangent of boron nitride. The thickness of the polydopamine layer can be controlled by the polymerization time.

[0107] After the polydopamine is attached to the surface, the boron nitride filler may be heat-treated. This allows for the production of a polydopamine film with even higher purity. The heat-treatment method is not particularly limited. The heat-treatment can be carried out using a known heat-treatment device such as a sintering device, an electric furnace, or a hot plate. In particular, it is desirable to carry out the heat-treatment using a sintering device or an electric furnace, as this allows for easy temperature control.

[0108] The heat treatment can be carried out by heating the ambient temperature of the boron nitride filler to a range of 100° C. to 400° C. The heating time is, for example, 1 hour to 48 hours.

[0109] Then, a functional group (X) is introduced into the polydopamine attached to the surface of the boron nitride filler, thereby forming a polydopamine layer from the polydopamine (C). The introduction of the functional group (X) is not particularly limited, but can be performed by, for example, acylation treatment or treatment with a silane coupling agent.

[0110] In the acylation treatment of polydopamine (C), the polydopamine is reacted with an acylating agent in the presence of a catalyst to acylate at least a portion of the hydroxyl groups of the polydopamine, thereby introducing the functional group (X).

[0111] The acylating agent is not particularly limited as long as it is capable of reacting with polar functional groups, such as hydroxyl groups, contained in polydopamine to acylate them. The acylating agent may be an acid anhydride. Examples of known acylating agents include carboxylic acid anhydrides. More specifically, examples include methacrylic acid anhydride, acetic anhydride, benzoic acid anhydride, and propanoic acid anhydride. The acid anhydride may include at least one selected from the group consisting of methacrylic acid anhydride, acrylic acid anhydride, acetic anhydride, and benzoic acid anhydride. When the acylating agent has a terminal double bond, this double bond reacts with the reactive residue of the resin of the insulating layer to form a bond, thereby improving the adhesion between the thermosetting compound (A) and the inorganic filler (B). From this perspective, methacrylic acid anhydride or acetic anhydride is particularly preferred as the acylating agent.

[0112] In addition to the above-mentioned acylation treatment, a functional group (X) can be introduced into the polydopamine (C) by treating it with a silane coupling agent having various functional groups.

[0113] Examples of silane coupling agents include methacryl silane coupling agents, vinyl silane coupling agents, styryl silane coupling agents, acrylic silane coupling agents, phenylamino silane coupling agents, epoxy silane coupling agents, maleimide silane coupling agents, etc. The method of treatment with a silane coupling agent is not particularly limited, but for example, polydopamine (C) in which at least a portion of the hydroxyl groups contained in the polydopamine have been substituted with the functional group (X) can be obtained by mixing the polydopamine-attached boron nitride filler in an aqueous solution containing a silane coupling agent having a functional group (X) and then drying the mixture.

[0114] When the above-mentioned acylation treatment or the treatment of introducing the functional group (X) using the above-mentioned silane coupling agent is performed, the polydopamine (C) of the present embodiment may further have at least one structure selected from the structures represented by the following formula (1) and the following formula (2):

[0115]

[0116]

[0117] It is believed that such a structure has the advantage of strengthening the bond between the cured thermosetting resin (A) and the boron nitride filler to which the polydopamine film (C) is attached.

[0118] Other Inorganic Fillers The resin composition of the present embodiment may contain only the boron nitride filler (B1) as the inorganic filler (B), or may contain an inorganic filler other than the boron nitride filler (B1).

[0119] The inorganic filler other than the boron nitride filler (B1) is not particularly limited as long as it can be used as an inorganic filler contained in a resin composition. For example, boron nitride fillers other than the boron nitride filler (B1), silica fillers, alumina fillers, titanium oxide fillers, metal oxide fillers such as magnesium oxide and mica, aluminum hydroxide fillers, metal hydroxide fillers such as magnesium hydroxide, talc fillers, aluminum borate fillers, barium sulfate fillers, aluminum nitride fillers, silicon nitride fillers, magnesium carbonate fillers such as anhydrous magnesium carbonate, and calcium carbonate fillers. Among these, preferred inorganic fillers other than the boron nitride filler (B1) include silica fillers, anhydrous magnesium carbonate fillers, alumina fillers, silicon nitride fillers, and boron nitride fillers with no dopamine attached to the surface. The silica filler is not particularly limited, and examples thereof include crushed silica fillers and silica particle fillers, with silica particle fillers being preferred. The magnesium carbonate filler is not particularly limited, but anhydrous magnesium carbonate (synthetic magnesite) filler is preferred.

[0120] The inorganic filler other than the boron nitride filler (B1) may be a surface-treated or untreated inorganic filler, and examples of the surface treatment include treatment with a silane coupling agent.

[0121] The content of the inorganic filler (B) is preferably 40 to 85 parts by weight, based on 100 parts by weight of the total of the thermosetting compound (A) and the inorganic filler (B). It is more preferably 40 to 80 parts by weight. Furthermore, the content of the boron nitride filler (B1) in the inorganic filler (B) is preferably 10 to 90% by mass, more preferably 10 to 70% by mass, based on the total amount of the inorganic filler (B). Having the content of the boron nitride filler (B1) within the above range is believed to have the advantage of ensuring high thermal conductivity and adhesion.

[0122] (Silane Coupling Agent) The resin composition of the present embodiment may further contain a silane coupling agent. This is thought to more reliably substitute the hydroxyl groups in the polydopamine (C) with the functional groups (X), thereby further improving the adhesion between the resin component and boron nitride.

[0123] Examples of the silane coupling agent include silane coupling agents 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 a phenylamino group. That is, the silane coupling agent includes compounds having at least one reactive functional group selected from a vinyl group, a styryl group, a methacryloyl group, an acryloyl group, and a phenylamino group, and further having a hydrolyzable group such as a methoxy group or an ethoxy group.

[0124] Examples of the silane coupling agent include those having a vinyl group, such as vinyltriethoxysilane and vinyltrimethoxysilane. Examples of the silane coupling agent include those having a styryl group, such as p-styryltrimethoxysilane and p-styryltriethoxysilane, which have a styrene structure represented by the above formula (S). Examples of the silane coupling agent include those having a methacryloyl group, such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropylethyldiethoxysilane. Examples of the silane coupling agent include those having an acryloyl group, such as 3-acryloxypropyltrimethoxysilane and 3-acryloxypropyltriethoxysilane. Examples of the silane coupling agent include those having a phenylamino group, such as N-phenyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltriethoxysilane.

[0125] When 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 per 100 parts by mass of the thermosetting compound (A).

[0126] (Reaction initiator) The resin composition of the present embodiment may further contain a reaction initiator. The radical polymerization (curing) reaction of the resin composition can proceed even without a reaction initiator. However, depending on the process conditions, it may be difficult to raise the temperature high enough for curing to proceed, so a reaction initiator may be added.

[0127] The reaction initiator is not particularly limited as long as it can accelerate the curing reaction of the resin composition. Specific examples include metal oxides, azo compounds, and peroxides, and preferably includes at least one of peroxides and azo compounds.

[0128] Specific examples of metal oxides include metal carboxylates.

[0129] Examples of organic peroxides include 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-diphenoquinone, chloranil, 2,4,6-tri-t-butylphenoxyl, t-butylperoxyisopropyl monocarbonate, and azobisisobutyronitrile.

[0130] Specific examples of the azo compound include 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(N-butyl-2-methylpropionamide), and 2,2'-azobis(2-methylbutyronitrile).

[0131] The above-mentioned reaction initiators may be used alone or in combination of two or more kinds.

[0132] When the resin composition of the present embodiment contains the reaction initiator, the content thereof is not particularly limited, but is, for example, preferably 0.1 to 5.0 parts by mass, more preferably 0.5 to 3.0 parts by mass, and even more preferably 0.5 to 2.0 parts by mass relative to 100 parts by mass of the thermosetting compound (A).

[0133] (Other Components) The resin composition according to the present embodiment may contain components other than the above-described components (other components) as needed, as long as the effects of the present invention are not impaired. Examples of other components contained in the resin composition according to the present embodiment may further include additives such as flame retardants, antifoaming agents, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, dyes, pigments, dispersants, and lubricants.

[0134] (Production Method) The method for producing the resin composition of the present embodiment is not particularly limited, and examples thereof include a method in which the thermosetting compound (A) is mixed with other organic components as necessary, and then the inorganic filler (B) is added. Specifically, in the case of obtaining a varnish-like composition containing an organic solvent, the method described in the description of the prepreg below can be used.

[0135] Furthermore, by using the resin composition according to this embodiment, a prepreg, a metal-clad laminate, a wiring board, a resin-coated metal foil, and a resin-coated film can be obtained as follows.

[0136] The cured product of the resin composition preferably has a thermal conductivity of 1.0 W / m K or more and a dielectric loss tangent at a frequency of 10 GHz of 0.003 or less. By using the resin composition of this embodiment, the cured product can have both high thermal conductivity and low dielectric properties, and excellent adhesion can also be obtained. The upper limit of the thermal conductivity is not particularly limited, but is preferably 50 W / m K or less from the viewpoint of the fillability of the inorganic filler in the resin composition.

[0137] 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention. In the following description, the respective symbols represent the following: 1 prepreg, 2 resin composition or semi-cured resin composition, 3 fibrous base material, 11 metal-clad laminate, 12 insulating layer, 13 metal foil, 14 wiring, 21 wiring board, 31 resin-coated metal foil, 32, 42 resin layer, 41 resin-coated film, 43 support film.

[0138] 1, the prepreg 1 according to this embodiment comprises the resin composition or a semi-cured product of the resin composition 2, and a fibrous base material 3. This prepreg 1 comprises the resin composition or a semi-cured product of the resin composition 2, and the fibrous base material 3 present in the resin composition or the semi-cured product of the resin composition 2.

[0139] In this embodiment, the semi-cured product refers to a resin composition that has been partially cured to the extent that it can be further cured. That is, the semi-cured product refers to a resin composition that has been semi-cured (B-staged). For example, when a resin composition is heated, the viscosity initially gradually decreases, then curing begins, and then curing begins again, and the viscosity gradually increases. In such a case, the semi-cured state may refer to a state between when the viscosity begins to increase and when the composition is completely cured.

[0140] Furthermore, the prepreg obtained using the resin composition according to this embodiment may comprise a semi-cured product of the resin composition as described above, or may comprise the uncured resin composition itself. That is, it may be a prepreg comprising a semi-cured product of the resin composition (the resin composition in B stage) and a fibrous base material, or a prepreg comprising the resin composition before curing (the resin composition in A stage) and a fibrous base material. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried.

[0141] When producing a prepreg, the resin composition 2 is often prepared in a varnish form and used to impregnate the fibrous base material 3, which is the base material for forming the prepreg. That is, the resin composition 2 is usually often a resin varnish prepared in a varnish form. Such a varnish-like resin composition (resin varnish) is prepared, for example, as follows.

[0142] First, each component of the resin composition that is soluble in an organic solvent is added to the organic solvent and dissolved. Heating may be performed as necessary. Subsequently, components that are insoluble in the organic solvent (e.g., inorganic fillers, etc.) are added as needed, and the mixture is dispersed using a ball mill, bead mill, planetary mixer, roll mill, or the like until a predetermined dispersion state is achieved, thereby preparing a varnish-like resin composition. The organic solvent used here is not particularly limited as long as it dissolves the modified polyphenylene ether compound, the curing agent, etc., and does not inhibit the curing reaction. Specific examples include toluene and methyl ethyl ketone (MEK), etc.

[0143] The method for producing the prepreg is not particularly limited as long as it can produce the prepreg. Specifically, when producing the prepreg, the resin composition used in the present embodiment is often prepared in the form of a varnish as described above and used as a resin varnish.

[0144] Specific examples of the fibrous substrate include glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. The use of glass cloth provides a laminate with excellent mechanical strength, and flattened glass cloth is particularly preferred. A specific example of the flattening process is a method in which glass cloth is continuously pressed with a press roll at an appropriate pressure to compress the yarns flat. The thickness of commonly used fibrous substrates is, for example, 0.01 mm or more and 0.3 mm or less.

[0145] The method for producing the prepreg is not particularly limited as long as it can produce the prepreg. Specifically, when producing the prepreg, the resin composition according to the present embodiment is often prepared in the form of a varnish as described above and used as a resin varnish.

[0146] The prepreg 1 can be produced, for example, by impregnating a fibrous substrate 3 with a resin composition 2, for example, a resin composition 2 prepared in a varnish form, followed by drying. The resin composition 2 is impregnated into the fibrous substrate 3 by immersion, coating, or the like. Impregnation can be repeated multiple times as necessary. In this case, by repeating the impregnation using multiple resin compositions with different compositions and concentrations, it is possible to adjust the final composition and impregnation amount to the desired one.

[0147] The fibrous substrate 3 impregnated with the resin composition (resin varnish) 2 is heated under desired conditions, for example, at 80°C to 180°C for 1 minute to 10 minutes. This heating produces a prepreg 1 in an uncured (A-stage) or semi-cured (B-stage) state. The heating also volatilizes the organic solvent from the resin varnish, reducing or eliminating the organic solvent.

[0148] The resin composition according to this embodiment or a prepreg comprising a semi-cured product of this resin composition is a prepreg from which a cured product having low dielectric properties, high thermal conductivity, and excellent adhesion can be suitably obtained.

[0149] [Metal-clad laminate] FIG. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate 11 according to an embodiment of the present invention.

[0150] As shown in FIG. 2, the metal-clad laminate 11 is composed of an insulating layer 12 containing a cured product of the prepreg 1 shown in FIG. 1 and a metal foil 13 laminated together with the insulating layer 12. That is, the metal-clad laminate 11 has an insulating layer 12 containing a cured product of a resin composition and a metal foil 13 provided on the insulating layer 12. The insulating layer 12 may be composed of either a cured product of the resin composition or a cured product of the prepreg. The thickness of the metal foil 13 varies depending on the performance required of the final wiring board and is not particularly limited. The thickness of the metal foil 13 can be appropriately set depending on the desired purpose, and is preferably, for example, 0.2 to 70 μm. Examples of the metal foil 13 include copper foil and aluminum foil. When the metal foil is thin, it may be a carrier-attached copper foil equipped with a release layer and a carrier to improve handling.

[0151] The method for producing the metal-clad laminate 11 is not particularly limited as long as it can produce the metal-clad laminate 11. Specifically, a method for producing the metal-clad laminate 11 using a prepreg 1 can be used. Examples of such a method include stacking one or more prepregs 1, placing a metal foil 13 such as copper foil on both sides or one side of the prepreg 1, and then heat-pressing and molding the metal foil 13 and the prepreg 1 to form an integrated laminate. In other words, the metal-clad laminate 11 can be obtained by laminating the metal foil 13 on the prepreg 1 and then heat-pressing and molding the laminate. The heat-pressing conditions can be appropriately set depending on the thickness of the metal-clad laminate 11 to be produced, the type of composition of the prepreg 1, and other factors. For example, the temperature can be 170 to 230°C, the pressure can be 3 to 4 MPa, and the time can be 60 to 150 minutes. The metal-clad laminate can also be produced without using a prepreg. For example, a method may be used in which a varnish-like resin composition is applied onto a metal foil to form a layer containing the resin composition on the metal foil, and then the layer is heated and pressed.

[0152] The metal-clad laminate having an insulating layer containing a cured product of the resin composition according to this embodiment is a metal-clad laminate having an insulating layer with low dielectric properties, high thermal conductivity, and excellent adhesion to the metal foil.

[0153] [Wiring Board] FIG. 3 is a schematic cross-sectional view showing an example of a wiring board 21 according to an embodiment of the present invention.

[0154] 3, wiring board 21 according to this embodiment is composed of insulating layer 12, which is formed by curing prepreg 1 shown in FIG. 1, and wiring 14, which is laminated together with insulating layer 12 and formed by partially removing metal foil 13. That is, wiring board 21 has insulating layer 12 containing a cured product of a resin composition, and wiring 14 provided on insulating layer 12. Furthermore, insulating layer 12 may be made of a cured product of the resin composition, or may be made of a cured product of the prepreg.

[0155] The method for manufacturing the wiring board 21 is not particularly limited as long as the wiring board 21 can be manufactured. Specific examples include a method of manufacturing the wiring board 21 using the prepreg 1. Examples of this method include a method of manufacturing the wiring board 21 in which wiring is provided as a circuit on the surface of the insulating layer 12 by etching the metal foil 13 on the surface of the metal-clad laminate 11 manufactured as described above. That is, the wiring board 21 is obtained by forming a circuit by partially removing the metal foil 13 on the surface of the metal-clad laminate 11. In addition to the above methods, examples of the method for forming a circuit include circuit formation by a semi-additive process (SAP) or a modified semi-additive process (MSAP). The wiring board 21 has an insulating layer 12 that has low dielectric properties, high heat resistance, and can favorably maintain its low dielectric properties even after a water absorption treatment.

[0156] Such a wiring board is a wiring board that has an insulating layer that has low dielectric properties, high thermal conductivity, and excellent adhesion to the metal foil.

[0157] [Resin-Coated Metal Foil] FIG. 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil 31 according to this embodiment.

[0158] As shown in Fig. 4, the resin-coated metal foil 31 according to this embodiment comprises a resin layer 32 containing the resin composition or a semi-cured product of the resin composition, and a metal foil 13. The resin-coated metal foil 31 has the metal foil 13 on the surface of the resin layer 32. That is, the resin-coated metal foil 31 comprises the resin layer 32 and the metal foil 13 laminated together with the resin layer 32. The resin-coated metal foil 31 may also comprise another layer between the resin layer 32 and the metal foil 13.

[0159] The resin layer 32 may contain a semi-cured product of the resin composition as described above, or may contain the uncured resin composition. That is, the resin-coated metal foil 31 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition in B-stage) and a metal foil, or a resin layer containing the resin composition before curing (the resin composition in A-stage) and a metal foil. The resin layer may contain the resin composition or a semi-cured product of the resin composition, and may or may not contain a fibrous substrate. The resin composition or the semi-cured product of the resin composition may be obtained by drying or heat-drying the resin composition. The fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0160] The metal foil may be any metal foil used in metal-clad laminates, including, for example, copper foil and aluminum foil.

[0161] The resin-coated metal foil 31 and the resin-coated film 41 may be provided with a cover film or the like, as necessary. By providing a cover film, it is possible to prevent the inclusion of foreign matter, etc. The cover film is not particularly limited, but examples thereof include polyolefin film, polyester film, polymethylpentene film, and films formed by providing a release agent layer on these films.

[0162] The method for producing the resin-coated metal foil 31 is not particularly limited as long as it can produce the resin-coated metal foil 31. Examples of methods for producing the resin-coated metal foil 31 include a method of applying the varnish-like resin composition (resin varnish) to the metal foil 13 and heating it. The varnish-like resin composition is applied to the metal foil 13 using, for example, 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 shorter. The heated resin composition is formed on the metal foil 13 as an uncured resin layer 32. Note that the heating volatilizes the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0163] The resin-coated metal foil having a resin layer containing the resin composition according to this embodiment or a semi-cured product of this resin composition is a resin-coated metal foil that can suitably produce a cured product that has low dielectric properties, high thermal conductivity, and excellent adhesion to the metal foil.

[0164] [Resin-Coated Film] FIG. 5 is a schematic cross-sectional view showing an example of a resin-coated film 41 according to this embodiment.

[0165] 5 , the resin-coated film 41 according to this embodiment includes a resin layer 42 containing the resin composition or a semi-cured product of the resin composition, and a support film 43. The resin-coated film 41 includes the resin layer 42 and the support film 43 laminated together with the resin layer 42. The resin-coated film 41 may also include another layer between the resin layer 42 and the support film 43.

[0166] The resin layer 42 may contain a semi-cured product of the resin composition as described above, or may contain the uncured resin composition. That is, the resin-coated film 41 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition in B-stage) and a support film, or a resin-coated film comprising a resin layer containing the resin composition before curing (the resin composition in A-stage) and a support film. The resin layer may contain the resin composition or a semi-cured product of the resin composition, and may or may not contain a fibrous substrate. The resin composition or the semi-cured product of the resin composition may be obtained by drying or heat-drying the resin composition. The fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0167] Furthermore, any support film used for a resin-coated film can be used without limitation as the support film 43. Examples of the support film include electrically insulating films such as polyester film, polyethylene terephthalate (PET) film, polyimide film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, polyamide film, polycarbonate film, and polyarylate film.

[0168] The resin-coated film 41 may be provided with a cover film or the like as necessary. By providing a cover film, it is possible to prevent the inclusion of foreign matter, etc. The cover film is not particularly limited, but examples thereof include a polyolefin film, a polyester film, and a polymethylpentene film.

[0169] The support film and cover film may be subjected to surface treatment such as matte treatment, corona treatment, release treatment, and roughening treatment, if necessary.

[0170] The method for producing the resin-coated film 41 is not particularly limited as long as it can produce the resin-coated film 41. Examples of methods for producing the resin-coated film 41 include a method in which the varnish-like resin composition (resin varnish) is applied to a support film 43 and heated. The varnish-like resin composition is applied to the support film 43 using, for example, 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 shorter. The heated resin composition is formed on the support film 43 as an uncured resin layer 42. The heating can volatilize the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0171] A resin-coated film having a resin layer containing the resin composition of this embodiment or a semi-cured product of this resin composition is a resin-coated film that can suitably produce a cured product with low dielectric properties, high thermal conductivity, and excellent adhesion.

[0172] This specification discloses various aspects of the technology as described above, but the main technologies among them are summarized below.

[0173] A resin composition according to a first aspect of the present invention is a resin composition comprising a thermosetting compound (A) and an inorganic filler (B), wherein the thermosetting compound (A) comprises at least one radically polymerizable compound (A1) selected from the group consisting of polyphenylene ether compounds having a reactive unsaturated group, hydrocarbon compounds having a reactive unsaturated group, and maleimide compounds having two or more maleimide groups, and the inorganic filler (B) comprises a boron nitride filler (B1), and polydopamine (C) having a functional group (X) reactive with the radically polymerizable compound (A1) is attached to the surface of the boron nitride filler (B1).

[0174] The resin composition according to the second aspect is the resin composition according to the first aspect, wherein the functional group (X) includes at least one selected from the group consisting of an epoxy group, a phenylamino group, a vinyl group, an acrylic group, a methacrylic group, an allyl group, a styrene structure, and a maleimide group.

[0175] The resin composition according to the third aspect is the resin composition according to the second aspect, wherein the polydopamine (C) further has at least one structure selected from the structures represented by the above formula (1) and the above formula (2).

[0176] A resin composition according to a fourth aspect is the resin composition of any one of the first to third aspects, wherein the polydopamine (C) forms a polydopamine layer on the surface of the boron nitride filler (B1), and the maximum thickness of the dopamine layer is 0.1 nm or more and 100 nm or less.

[0177] A resin composition according to a fifth aspect is the resin composition of any one of the first to fourth aspects, wherein the thermal conductivity of a cured product of the resin composition is 1 W / mK or more and 50 W / mK or less.

[0178] A resin composition according to a sixth aspect is the resin composition of any one of the first to fifth aspects, wherein the content of the inorganic filler (B) is 40 to 85 parts by weight per 100 parts by weight of the total of the thermosetting compound (A) and the inorganic filler (B).

[0179] A resin composition according to a seventh aspect is the resin composition of any one of the first to sixth aspects, wherein the content of the boron nitride filler (B1) is 10 to 90 mass% relative to the inorganic filler (B).

[0180] The resin composition according to an eighth aspect is the resin composition according to any one of the first to seventh aspects, further comprising a silane coupling agent.

[0181] A prepreg according to a ninth aspect of the present invention is characterized by comprising the resin composition of any one of the first to eighth aspects or a semi-cured product of the resin composition, and a fibrous base material.

[0182] A resin-coated film according to a tenth aspect of the present invention is characterized by comprising a resin layer containing the resin composition of any one of the first to eighth aspects or a semi-cured product of the resin composition, and a support film.

[0183] The resin-coated metal foil according to an eleventh aspect of the present invention is characterized by comprising a resin layer containing the resin composition of any one of the first to eighth aspects or a semi-cured product of the resin composition, and a metal foil.

[0184] A metal-clad laminate according to a twelfth aspect of the present invention comprises an insulating layer containing a cured product of the resin composition according to any one of the first to eighth aspects or a cured product of the prepreg according to the ninth aspect, and a metal foil.

[0185] A wiring board according to a thirteenth aspect of the present invention is characterized by comprising an insulating layer containing a cured product of the resin composition of any one of the first to eighth aspects or a cured product of the prepreg of the ninth aspect, and wiring.

[0186] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0187] In this example, each component used in preparing the resin composition will be described.

[0188] (Radical polymerizable compound (A1)) Modified polyphenylene ether compound (modified PPE): polyphenylene ether compound having a methacryloyl group at its terminal ("SA9000" manufactured by SABIC Innovative Plastics, weight average molecular weight Mw 2000, number of terminal functional groups 2) Hydrocarbon compound: polybutadiene ("Ricon (registered trademark)" manufactured by Cray Valley Chemical Industries, Ltd.) Maleimide compound: bismaleimide ("MIR-5000" manufactured by Nippon Kayaku Co., Ltd.)

[0189] (Other thermosetting compounds) Curing agent 1: triallyl isocyanurate (TAIC manufactured by Nippon Kasei Chemical Co., Ltd.) Curing agent 2: benzoxazine compound ("P-d" manufactured by Shikoku Chemical Industry Co., Ltd.) Other thermosetting compounds: unmodified polyphenylene ether compound ("SA90" manufactured by SABIC Innovative Plastics)

[0190] (Reaction initiator) Peroxide initiator: PBP (1,3-bis(butylperoxyisopropyl)benzene; Perbutyl P manufactured by NOF Corporation)

[0191] (Inorganic fillers) Untreated boron nitride filler (BN): h-BN ("SGP" manufactured by Denka Co., Ltd. (average particle size: 18 μm)) Silica filler: "FB-7SDC" manufactured by Denka Co., Ltd. Alumina filler: "DAW-03AC" manufactured by Denka Co., Ltd.

[0192] Surface-treated boron nitride filler 1: polydopamine-treated boron nitride filler (no functional groups) As boron nitride (BN), h-BN (manufactured by Denka Company, "SGP") was used. Dopamine hydrochloride was added to a Tris-HCl solution whose pH had been adjusted to 8.5, and the mixture was stirred to obtain a dopamine solution (concentration: 23 mg / mL). 4.5 g of the boron nitride was added to the obtained dopamine solution. The solution temperature was set to 80°C, and the mixture was stirred with a magnetic stirrer for 1 hour. A solid was then obtained by filtration. The obtained solid was washed with water and then dried. This gave boron nitride particles having polydopamine attached thereto. Next, the obtained particles were heat-treated in an electric furnace at 200°C for 24 hours to obtain a polydopamine-treated boron nitride filler (surface-treated boron nitride filler 1, no functional groups). The polydopamine layer had a thickness of 2 nm.

[0193] The thickness of the polydopamine layer was measured by X-ray photoelectron spectroscopy (XPS). Specifically, XPS was used to detect the amounts of B, C, N, and O in the boron nitride layer in the depth direction from the surface. The regions where the amounts of C and O derived from the polydopamine film were increased relative to untreated boron nitride were identified, and these regions were defined as the polydopamine layer.

[0194] (Boron nitride filler (B1)) Surface-treated boron nitride filler 2: Polydopamine (C)-treated boron nitride filler (functional group (X): methacryl group) 50 mL of a methacrylsilane coupling agent ("KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.) was added to 1 L of toluene. 300 g of the surface-treated boron nitride filler 1 was then added. The liquid temperature was adjusted to 100°C in a heated oil bath, and the mixture was stirred at 500 rpm for 3 hours. The resulting solid was then cooled in toluene, filtered, washed with toluene, and dried to obtain surface-treated boron nitride filler 2 (containing methacryl groups).

[0195] Surface-treated boron nitride filler 3: Polydopamine (C)-treated boron nitride filler (functional group (X): vinyl group) Surface-treated boron nitride filler 3 (containing a vinyl group) was obtained in the same manner as for surface-treated boron nitride filler 2, except that 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.).

[0196] Surface-treated boron nitride filler 4: Polydopamine (C)-treated boron nitride filler (functional group (X): styrene structure) Surface-treated boron nitride filler 4 (containing a styrene structure) was obtained in the same manner as for surface-treated boron nitride filler 2, except that the methacryl 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.).

[0197] Surface-treated boron nitride filler 5: polydopamine (C)-treated boron nitride filler (functional group (X): acrylic group) Surface-treated boron nitride filler 5 (containing an acrylic group) was obtained in the same manner as for surface-treated boron nitride filler 2, except that the methacryl silane coupling agent ("KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.) was changed to an acrylic silane coupling agent ("KBM-5103" manufactured by Shin-Etsu Chemical Co., Ltd.).

[0198] Surface-treated boron nitride filler 6: polydopamine (C)-treated boron nitride filler (functional group (X): methacryl group) Surface-treated boron nitride filler 6 (containing methacryl groups, dopamine layer thickness 20 nm) was obtained in the same manner as for surface-treated boron nitride filler 2, except that the stirring time with a magnetic stirrer after adding boron nitride to the dopamine solution was changed from 1 hour to 4 hours.

[0199] Surface-treated boron nitride filler 7: polydopamine (C)-treated boron nitride filler (functional group (X): methacryl group) Surface-treated boron nitride filler 7 (containing methacryl groups, dopamine layer thickness 100 nm) was obtained in the same manner as for surface-treated boron nitride filler 2, except that the stirring time with a magnetic stirrer after adding boron nitride to the dopamine solution was changed from 1 hour to 12 hours.

[0200] Surface-treated boron nitride filler 8: polydopamine (C)-treated boron nitride filler (acylated) 2.0 g of 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 to obtain a mixed solution. The temperature of the mixed solution was set to 25°C and stirred for 24 hours using a magnetic stirrer. The mixed solution was then filtered to obtain a solid. The obtained solid was washed with toluene and then dried. This resulted in surface-treated boron nitride filler 8 (acylated, containing methacrylic groups, dopamine layer thickness 2 nm) (a boron nitride filler to which polydopamine having the structure represented by formula (1) was attached).

[0201] (Silane coupling agent) Methacrylic silane coupling agent ("KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.)

[0202] [Examples 1 to 20 and Comparative Examples 1 to 4] (Preparation Method) First, each organic resin component other than the inorganic filler was added to toluene as a solvent and mixed to a solids concentration of approximately 40 to 80% by mass in the compositions (parts by mass) shown in Tables 1 and 2. The mixture was stirred for 60 minutes. Thereafter, each inorganic filler and coupling agent were added to the resulting liquid in the proportions (parts by mass) shown in Tables 1 and 2, and the inorganic filler was dispersed using a bead mill. This resulted in a varnish-like resin composition (varnish).

[0203] Next, an evaluation substrate (cured prepreg) was obtained as follows.

[0204] A fibrous substrate (glass cloth: #1078 type, L glass, manufactured by Asahi Kasei Corporation) was impregnated with the resulting varnish and then heated and dried for 3 minutes at 110°C to produce prepregs. One, two, or four of the resulting prepregs were then stacked, and copper foil (FV-WS copper foil, manufactured by Furukawa Electric Co., Ltd., thickness: 18 μm) was attached to both sides of each stack. The stack was heated to 200°C at a heating rate of 4°C / min, and heated and pressed at 200°C for 120 minutes at a pressure of 3 MPa to produce copper-clad laminates of three different thicknesses.

[0205] The copper-clad laminates prepared as described above were used as evaluation substrates and evaluated by the following methods. In the measurement of thermal conductivity described below, a cured product of one prepreg, a copper-clad laminate of two prepregs from which the copper foil had been removed, and a copper-clad laminate of four prepregs from which the copper foil had been removed (cured prepreg products) were used. In the evaluation test of dielectric properties (dielectric constant), a copper-clad laminate of four prepregs from which the copper foil had been removed (cured prepreg products) was used.

[0206] [Thermal Conductivity] The thermal conductivity of the obtained evaluation substrates (cured prepreg products) was measured by a method conforming to ASTM D5470. Specifically, using a thermal property evaluation device (T3Ster DynTIM Tester manufactured by Mentor Graphics), the thermal resistance and thickness of the obtained evaluation substrates (cured products of one prepreg, cured products of two prepregs, and cured products of four prepregs) were measured, the measured values ​​were plotted on 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.

[0207] [Dielectric Properties (Dielectric Constant)] The dielectric loss tangent (Df) of the evaluation substrate (cured prepreg) at 10 GHz was measured by a cavity resonator perturbation method. Specifically, the dielectric loss tangent of the evaluation substrate at 10 GHz was measured using a network analyzer (N5230A manufactured by Keysight Technologies, Inc.). The pass criterion in this example was Df≦0.003.

[0208] [Copper Foil Peel Strength] First, for the peel strength (copper foil peel) test, a copper clad laminate (CCL) was produced using the prepregs of each Example and Comparative Example. Specifically, four prepregs were stacked, and 18 μm thick copper foil (FV-WS manufactured by Furukawa Electric Co., Ltd.) was attached to both surfaces of the stack. Heat and pressure were applied for 120 minutes under vacuum conditions at a temperature of 200°C and a pressure of 3 MPa to obtain a 510 μm thick copper clad laminate (CCL) (evaluation substrate) with copper foil attached to both surfaces.

[0209] The resulting CCL was used to measure the peel strength of the copper foil from the insulating layer in accordance with JIS C 6481. A pattern 10 mm wide and 100 mm long was formed, and the copper foil was peeled off at a rate of 50 mm / min using a tensile tester, and the peel strength was measured. The measurement unit was kN / m. The pass criterion in this example was 0.40 kN / m or more.

[0210] The results of the above evaluations are shown in Tables 1 and 2.

[0211]

[0212]

[0213] (Discussion) As can be seen from Tables 1 and 2, it was confirmed that in all of the examples using the resin composition of the present invention, cured products having low dielectric properties, high thermal conductivity, and excellent adhesion were obtained.

[0214] On the other hand, as shown in Table 2, the sample of Comparative Example 1, which did not contain the radical polymerizable compound (A1), failed to achieve sufficient dielectric properties and adhesion. Furthermore, the samples of Comparative Examples 2 and 3, which used a boron nitride filler that was not surface-treated via a polydopamine film as the inorganic filler, resulted in poor adhesion. Comparison of Comparative Examples 2 and 3 confirmed that increasing the content of boron nitride filler improved thermal conductivity, but also resulted in poorer adhesion. Furthermore, Comparative Example 4, which used a boron nitride filler that was surface-treated with polydopamine but did not have a functional group (X), also failed to achieve sufficient adhesion.

[0215] This application is based on Japanese Patent Application No. 2023-140937, filed on August 31, 2023, the contents of which are incorporated herein by reference.

[0216] In order to express the present invention, the present invention has been properly and sufficiently described above through embodiments with reference to specific examples, drawings, etc., but it should be recognized that those skilled in the art can easily make changes and / or improvements to the above-described embodiments. Therefore, unless changes or improvements made by those skilled in the art deviate from the scope of the claims set forth in the claims, such changes or improvements are construed as being encompassed within the scope of the claims.

[0217] The present invention has wide industrial applicability in the technical fields of electronic materials, electronic devices, optical devices, and the like.

Claims

1. A resin composition comprising a thermosetting compound (A) and an inorganic filler (B), wherein the thermosetting compound (A) comprises at least one radically polymerizable compound (A1) selected from the group consisting of polyphenylene ether compounds having a reactive unsaturated group, hydrocarbon compounds having a reactive unsaturated group, and maleimide compounds having two or more maleimide groups, and the inorganic filler (B) comprises a boron nitride filler (B1), and a polydopamine (C) having a functional group (X) that reacts with the radically polymerizable compound (A1) is attached to the surface of the boron nitride filler (B1).

2. The resin composition according to claim 1, wherein the functional group (X) comprises at least one selected from the group consisting of an epoxy group, a phenylamino group, a vinyl group, an acrylic group, a methacrylic group, an allyl group, a styrene structure, and a maleimide group.

3. The resin composition according to claim 2, wherein the polydopamine (C) further has at least one structure selected from the structures represented by the following formula (1) and the following formula (2).

4. The resin composition according to claim 1, wherein the polydopamine (C) forms a polydopamine layer on the surface of the boron nitride filler (B1), and the maximum thickness of the dopamine layer is 0.1 nm or more and 100 nm or less.

5. The resin composition according to claim 1, wherein the cured product of the 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, wherein the content of the inorganic filler (B) is 40 to 85 parts by weight per 100 parts by weight of the total of the thermosetting compound (A) and the inorganic filler (B).

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

8. The resin composition according to claim 1, further comprising a silane coupling agent.

9. A prepreg comprising the resin composition according to any one of claims 1 to 8 or a semi-cured product of said resin composition and a fibrous base material.

10. A resin-coated film comprising a resin layer containing the resin composition according to any one of claims 1 to 8 or a semi-cured product of said resin composition, and a support film.

11. A resin-coated metal foil comprising a resin layer containing the resin composition according to any one of claims 1 to 8 or a semi-cured product of said resin composition, and a metal foil.

12. A metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 8 and a metal foil.

13. A wiring board comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 8 and wiring.

14. A metal-clad laminate comprising an insulating layer containing the cured product of the prepreg according to claim 9 and a metal foil.

15. A wiring board comprising an insulating layer containing the cured product of the prepreg according to claim 9 and wiring.

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