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

Abstract

To provide a resin composition from which a cured product having low dielectric characteristics and high thermostability and hardly influenced by change in external environment and the like can be obtained and which has moldability applicable to a laminate wiring board.SOLUTION: A resin composition includes: a modified polyphenylene ether compound terminal-modified with a substituent having a carbon-carbon unsaturated double bond; and a free radical compound. The free radical compound is such a compound as to contain one or more of 5 membered-ring or 6 membered-ring containing nitrogen, represented by, for example, formula (7) shown below.SELECTED DRAWING: None

Description

[Technical Field]

[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. [Background technology]

[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 curable composition containing a radically polymerizable compound having an unsaturated bond in the molecule, an inorganic filler containing a predetermined amount of metal oxide, and a predetermined amount of a dispersant having an acidic group and a basic group has been reported (Patent Document 1).

[0004] Patent Document 1 discloses that it is possible to obtain a curable composition that can be used to suitably produce a cured product that has excellent dielectric properties and heat resistance and a small coefficient of thermal expansion. It is believed that a wiring board obtained using a resin composition with low dielectric properties such as a dielectric constant and a dielectric loss tangent, as described in Patent Document 1, can reduce loss during signal transmission.

[0005] On the other hand, wiring boards are required to have dielectric properties that do not deteriorate even when used for a long period of time. To prevent the dielectric properties of wiring boards from deteriorating over the long term, it is necessary that the electrical properties (dielectric loss tangent in the examples) of the cured material that constitutes the wiring board do not change.

[0006] A common method for observing long-term changes in electrical properties is to conduct a treatment test under a thermal environment, and it is required that the electrical properties of the cured product change little even under a thermal environment.

[0007] Furthermore, the substrate of the wiring board is required to maintain its low dielectric properties even if it absorbs water, so that the wiring board can be used in a high humidity environment.

[0008] In other words, in order to enable wiring boards to be used in high temperature or high humidity environments, the substrate material that constitutes the substrate of the wiring board is required to have dielectric properties that are not affected by high temperatures or water absorption.

[0009] Furthermore, when applied to wiring boards, particularly multilayer laminated wiring boards, it is necessary to fill the circuit pattern (between the wiring) with a base material (insulating layer molding material), and therefore sufficient resin flowability is required. In this regard, the above-mentioned prior art does not describe a technique for filling the molding material into the fine circuit pattern (between the wiring). [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-56367 Summary of the Invention

[0011] 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 heat resistance, and resistance to the effects of changes in the external environment, and that has moldability that enables application to laminated wiring boards. Another aim of the present invention is 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.

[0012] 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.

[0013] That is, a resin composition according to one embodiment of the present invention contains a modified polyphenylene ether compound terminally modified with a substituent having a carbon-carbon unsaturated double bond, and a free radical compound, wherein the free radical compound has in its molecule at least one free radical group selected from the group of structures represented by formulas (1), (2), (3), and (4) described below, and contains at least one compound selected from the compounds represented by formulas (7) to (9) described below. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a prepreg according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate according to an embodiment of the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional view showing an example of a wiring board according to an embodiment of the present invention. [Figure 4] 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. [Figure 5] FIG. 5 is a schematic cross-sectional view showing an example of a resin-coated film according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be specifically described, but the present invention is not limited to these.

[0016] [Resin composition] A resin composition according to an embodiment of the present invention comprises a modified polyphenylene ether compound terminally modified with a substituent having a carbon-carbon unsaturated double bond, and a free radical compound, wherein the free radical compound has in its molecule at least one free radical group selected from the group of structures represented by the following formulas (1), (2), (3), and (4):

[0017] [ka]

[0018] [ka]

[0019] [ka]

[0020] [ka]

[0021] By adding a free radical compound having the above-described structure to a resin composition containing the modified polyphenylene ether compound, a cured product can be obtained that has low dielectric properties and high heat resistance and can favorably maintain its low dielectric properties even after heat treatment or water absorption treatment, and a resin composition with excellent moldability can be obtained.

[0022] That is, according to the present invention, it is possible to obtain a cured product having low dielectric properties and high heat resistance, which can favorably maintain low dielectric properties even after heat treatment or water absorption treatment, and it is possible to provide a resin composition having excellent moldability that allows for filling of circuit patterns.Furthermore, according to the present invention, by using the resin composition, it is possible to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board having excellent performance.

[0023] This is thought to be because the addition of a free radical compound can improve moldability while maintaining the properties of the cured product, such as a high Tg, to some extent.

[0024] First, each component of the resin composition of the present embodiment will be described.

[0025] (Modified polyphenylene ether compound) The modified polyphenylene ether compound of the present embodiment is not particularly limited as long as it is a modified polyphenylene ether compound whose terminals are modified with a substituent having a carbon-carbon unsaturated double bond. 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.

[0026] The substituent having a carbon-carbon unsaturated double bond is not particularly limited, and examples thereof include a substituent represented by the following formula (5) and a substituent represented by the following formula (6).

[0027] [ka]

[0028] In formula (5), p represents an integer of 0 to 10. Z represents an arylene group. R1 to R3 are each independent. That is, R1 to R3 may be the same group or different groups. R1 to R3 represent a hydrogen atom or an alkyl group.

[0029] In addition, in the formula (5), when p is 0, it means that Z is directly bonded to the end of the polyphenylene ether.

[0030] The arylene group of 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 polycyclic, 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.

[0031] [ka]

[0032] In formula (6), R4 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.

[0033] Preferred specific examples of the substituent represented by the formula (5) include, for example, a substituent containing a vinylbenzyl group. Examples of the substituent containing a vinylbenzyl group include, for example, a substituent represented by the following formula (10). Furthermore, examples of the substituent represented by the formula (6) include an acrylate group and a methacrylate group.

[0034] [ka]

[0035] 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.

[0036] The modified polyphenylene ether compound has a polyphenylene ether chain in the molecule, and preferably has, for example, a repeating unit represented by the following formula (11) in the molecule.

[0037] [ka]

[0038] In formula (11), t represents 1 to 50. R5 to R8 are each independent. That is, R5 to R8 may be the same group or different groups. R5 to R8 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.

[0039] Specific examples of the functional groups listed for R5 to R8 include the following.

[0040] 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.

[0041] 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.

[0042] 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).

[0043] 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.

[0044] 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.

[0045] 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.

[0046] The weight-average molecular weight (Mw) of the modified 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 modified polyphenylene ether compound has a repeating unit represented by the formula (11) in the molecule, t is preferably a numerical value such that the weight-average molecular weight of the modified polyphenylene ether compound falls within this range. Specifically, t is preferably 1 to 50.

[0047] When the weight-average molecular weight of the modified 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 normal 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 contrast, the modified polyphenylene ether compound according to this embodiment has at least one unsaturated double bond at its terminal, which is believed to result in a cured product with sufficiently high heat resistance. Furthermore, when the weight-average molecular weight of the modified 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 modified polyphenylene ether compound not only has excellent heat resistance but also has excellent moldability.

[0048] The average number of the substituents (number of terminal functional groups) at the molecular terminals per molecule of the modified polyphenylene ether compound is not particularly limited. Specifically, it is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.5 to 3. If the number of terminal functional groups is too small, it tends to be difficult to obtain a cured product with sufficient heat resistance. 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 shelf life and reduced fluidity of the resin composition. That is, when such a modified polyphenylene ether compound is used, insufficient fluidity may cause molding defects such as the generation of voids during multilayer molding, which may lead to moldability problems such as difficulty in obtaining a highly reliable printed wiring board.

[0049] The number of terminal functional groups in a modified polyphenylene ether compound may be, for example, a numerical value representing the average number of the above-mentioned substituents per molecule of all modified polyphenylene ether compounds present in 1 mole of the modified 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.

[0050] The intrinsic viscosity of the modified polyphenylene ether compound is not particularly limited. Specifically, it may be 0.03 to 0.12 dL / g, preferably 0.04 to 0.11 dL / g, and more preferably 0.06 to 0.095 dL / g. If the intrinsic viscosity is too low, the molecular weight tends to be low, and it tends to be difficult to achieve low dielectric properties such as a low dielectric constant and a low dielectric loss tangent. On the other hand, if the intrinsic viscosity is too high, the viscosity tends to be high, sufficient fluidity cannot be obtained, and the moldability of the cured product tends to be reduced. Therefore, if the intrinsic viscosity of the modified polyphenylene ether compound is within the above range, excellent heat resistance and moldability of the cured product can be achieved.

[0051] The intrinsic viscosity here is the intrinsic viscosity measured in methylene chloride at 25°C, and more specifically, for example, is the value measured using a viscometer for a 0.18 g / 45 ml methylene chloride solution (liquid temperature: 25°C). Examples of such a viscometer include the AVS500 Visco System manufactured by Schott.

[0052] Examples of the modified polyphenylene ether compound include a modified polyphenylene ether compound represented by the following formula (12) and a modified polyphenylene ether compound represented by the following formula (13). As the modified polyphenylene ether compound, these modified polyphenylene ether compounds may be used alone, or these two types of modified polyphenylene ether compounds may be used in combination.

[0053] [ka]

[0054] [ka]

[0055] In formula (12) and formula (13), R9 to 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. X1 and X2 each independently represent a substituent having a carbon-carbon unsaturated double bond. A and B represent repeating units represented by the following formula (14) and formula (15), respectively. In addition, in formula (13), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms.

[0056] [ka]

[0057] [ka]

[0058] In the formulas (14) and (15), m and n each represent an integer of 0 to 20. 25 ~R 28 and R 29 ~R32 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.

[0059] The modified polyphenylene ether compound represented by the formula (12) and the modified polyphenylene ether compound represented by the formula (13) are not particularly limited as long as they satisfy the above-mentioned constitution. Specifically, in the formulas (12) and (13), R9 to R 16 and R 17 ~R 24 As mentioned above, R9 to R 16 and R 17 ~R 24 may be the same group or different groups. 16 and R 17 ~R 24 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.

[0060] In the formulas (14) and (15), 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 numerical value of 0 to 20, n represents a numerical value of 0 to 20, and the sum of m and n represents a numerical 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 32represents 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.

[0061] R9~R 32 are the same as R5 to R8 in the above formula (11).

[0062] In the formula (13), 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 (16).

[0063] [ka]

[0064] In the formula (16), R 33 and R 34 are 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 (16) include a methylene group, a methylmethylene group, and a dimethylmethylene group, and among these, a dimethylmethylene group is preferred.

[0065] In the formula (12) and the formula (13), X1 and X2 are each independently a substituent having a carbon-carbon unsaturated double bond. The substituents X1 and X2 are not particularly limited as long as they are substituents having a carbon-carbon unsaturated double bond. Examples of the substituents X1 and X2 include the substituents represented by the formula (5) and the substituents represented by the formula (6). In the modified polyphenylene ether compound represented by the formula (12) and the modified polyphenylene ether compound represented by the formula (13), X1 and X2 may be the same or different substituents.

[0066] More specific examples of the modified polyphenylene ether compound represented by the formula (12) include modified polyphenylene ether compounds represented by the following formula (17).

[0067] [ka]

[0068] More specific examples of the modified polyphenylene ether compound represented by the formula (13) include a modified polyphenylene ether compound represented by the following formula (18) and a modified polyphenylene ether compound represented by the following formula (19).

[0069] [ka]

[0070] [ka]

[0071] In the above formulas (17) to (19), m and n have the same meaning as m and n in the above formulas (14) and (15), and are independently 0 to 20. In addition, in the above formulas (17) and (18), R1 to R3, p, and Z are the same as R1 to R3, p, and Z in the above formula (5). In addition, in the above formulas (18) and (19), Y is the same as Y in the above formula (13). In addition, in the above formula (19), R4 is the same as R4 in the above formula (6).

[0072] The method for synthesizing the modified polyphenylene ether compound used in the present embodiment is not particularly limited as long as it can synthesize a modified polyphenylene ether compound whose terminals are modified with a substituent having a carbon-carbon unsaturated double bond. Specific examples include a method of reacting polyphenylene ether with a compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded.

[0073] Examples of compounds in which a substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom include compounds in which a substituent represented by the formulas (5), (6), and (10) is bonded to a halogen atom. Specific examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom, with a chlorine atom being preferred. More specific examples of compounds in which a substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom include p-chloromethylstyrene and m-chloromethylstyrene.

[0074] The polyphenylene ether used as the raw material is not particularly limited as long as it can ultimately synthesize a predetermined modified polyphenylene ether compound. Specific examples include polyphenylene ethers composed of 2,6-dimethylphenol and at least one of a bifunctional phenol and a trifunctional phenol, and those containing polyphenylene ether as the main component, such as poly(2,6-dimethyl-1,4-phenylene oxide). Furthermore, a bifunctional phenol is a phenolic compound having two phenolic hydroxyl groups per molecule, such as tetramethylbisphenol A. Furthermore, a trifunctional phenol is a phenolic compound having three phenolic hydroxyl groups per molecule.

[0075] The modified polyphenylene ether compound can be synthesized by the method described above. Specifically, the polyphenylene ether described above and a compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded are dissolved in a solvent and stirred. By doing so, the polyphenylene ether reacts with the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, thereby obtaining the modified polyphenylene ether compound used in this embodiment.

[0076] The reaction is preferably carried out in the presence of an alkali metal hydroxide. It is believed that this allows the reaction to proceed smoothly. This is believed to be because the alkali metal hydroxide functions as a dehydrohalogenating agent, specifically, a dehydrochlorinating agent. That is, it is believed that the alkali metal hydroxide eliminates hydrogen halide from the phenol group of the polyphenylene ether and a compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and as a result, the substituent having a carbon-carbon unsaturated double bond is bonded to the oxygen atom of the phenol group in place of the hydrogen atom of the phenol group of the polyphenylene ether.

[0077] The alkali metal hydroxide is not particularly limited as long as it can act as a dehalogenating agent, and examples thereof include sodium hydroxide, etc. The alkali metal hydroxide is usually used in the form of an aqueous solution, specifically, an aqueous sodium hydroxide solution.

[0078] Reaction conditions such as reaction time and reaction temperature vary depending on the compound in which a substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom, and are not particularly limited as long as the conditions are such that the above-mentioned reaction proceeds favorably. Specifically, the reaction temperature is preferably room temperature to 100°C, more preferably 30 to 100°C. The reaction time is preferably 0.5 to 20 hours, more preferably 0.5 to 10 hours.

[0079] The solvent used in the reaction is not particularly limited as long as it can dissolve the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and does not inhibit the reaction between the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded. Specific examples include toluene.

[0080] The above reaction is preferably carried out in the presence of not only an alkali metal hydroxide but also a phase transfer catalyst. That is, the above reaction is preferably carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst. Doing so is believed to allow the reaction to proceed more smoothly. This is believed to be due to the following: A phase transfer catalyst has the function of incorporating an alkali metal hydroxide, is soluble in both a polar solvent phase such as water and a nonpolar solvent phase such as an organic solvent, and is capable of transferring between these phases. Specifically, when an aqueous solution of sodium hydroxide is used as the alkali metal hydroxide and an organic solvent such as toluene, which is incompatible with water, is used as the solvent, even if the aqueous solution of sodium hydroxide is added dropwise to the solvent being used for the reaction, the solvent and the aqueous solution of sodium hydroxide separate, and it is believed that the sodium hydroxide is unlikely to migrate to the solvent. In this case, it is believed that the aqueous solution of sodium hydroxide added as the alkali metal hydroxide is unlikely to contribute to promoting the reaction. On the other hand, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst, the alkali metal hydroxide is transferred to the solvent while being incorporated into the phase transfer catalyst, and the aqueous sodium hydroxide solution is thought to contribute more to promoting the reaction. Therefore, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst, the reaction is thought to proceed more smoothly.

[0081] The phase transfer catalyst is not particularly limited, but examples thereof include quaternary ammonium salts such as tetra-n-butylammonium bromide.

[0082] The resin composition used in the present embodiment preferably contains the modified polyphenylene ether compound obtained as described above as the modified polyphenylene ether compound.

[0083] (free radical compounds) The free radical compound used in this embodiment is not particularly limited as long as it is a free radical compound having at least one of the structures represented by the above formulas (1) to (4). By including such a free radical compound, the resin composition of this embodiment is believed to be able to exhibit excellent moldability (moldability that allows circuit patterns to be filled) while retaining properties such as low dielectric properties and heat resistance. Furthermore, it is believed that a cured product can be obtained that can favorably maintain low dielectric properties even after heat treatment or water absorption treatment.

[0084] Preferably, the free radical compound of this embodiment includes at least one compound selected from the compounds represented by the following formulas (7) to (9).

[0085] [ka]

[0086] [ka]

[0087] [ka]

[0088] In the formula (7) and the formula (8), X A and X B each independently represents a hydrogen atom, an amino group, a cyano group, a hydroxy group, an isothiocyanate group, a methoxy group, a carboxy group, a carbonyl group, an amido group, a benzoyloxy group, or an ether bond.

[0089] More specific examples of these include 4-acetamido, 4-glycidyloxy, 4-benzoyloxy, 4-(2-iodoacetamido), 4-[2-[2-(4-iodophenoxy)ethoxy]carbonyl]benzoyloxy, 4-methacryloyloxy, 4-oxo, and 4-propargyloxy.

[0090] In addition, in the formula (9), X C represents an alkylene group, an aromatic structure, a carbonyl group, an amide group, or an ether bond.

[0091] The alkylene group may have a linear, side-chain, and / or cyclic structure, and the length of the linear and side chains is not particularly limited. If the number of carbon atoms is too large, the solubility of the resin component in a solvent may decrease, so for example, the number of carbon atoms is preferably 16 or less, and particularly preferably about 8 or less.

[0092] When the alkylene group has a cyclic structure, examples thereof include a seven-membered ring, a six-membered ring, and a five-membered ring.

[0093] Examples of the aromatic structure include a phenyl group, a pyrrole group, and a thiazole group.

[0094] More specific free radical compounds preferably used in this embodiment include 4-amino-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-amino-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-carboxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-cyano-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-glycidyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxylbenzoate free radical, and 4-isothiocyanato-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-(2-iodoacetamido)-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-[2-[2-(4-iodophenoxy)ethoxy]carbonyl]benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-oxo-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-oxo-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 2,2,6,6-tetramethyl-4-(2-propynyloxy)piperidine 1-oxyl Free radical, 2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4,5-dihydro-4,4,5,5-tetramethyl-2-phenyl-1H-imidazol-1-yloxy-1-oxide, bis(2,2,6,6-tetramethyl-4-piperidyl-1-oxyl) sebacate, 3-carboxy-2,2,5,5-tetramethylpyrrolidine 1-oxyl Free radical, 4-(2-chloroacetamido)-2,2,6,Examples include 6-tetramethylpiperidine 1-oxyl free radical, 2-(4-nitrophenyl)-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl free radical, 2-(14-carboxytetradecyl)-2-ethyl-4,4-dimethyl-3-oxazolidinyloxy free radical, and 1,1-diphenyl-2-picrylhydrazyl free radical.

[0095] Various free radical compounds have been mentioned above, and these may be used alone or in combination of two or more.

[0096] The free radical compound of this embodiment as described above may be commercially available and is available from, for example, Tokyo Chemical Industry Co., Ltd.

[0097] (hardening agent) The resin composition of the present embodiment preferably further contains a curing agent.

[0098] The curing agent is not particularly limited as long as it can react with the modified polyphenylene ether compound to cure a resin composition containing the modified polyphenylene ether compound. Examples of the curing agent include curing agents having at least one functional group in the molecule that contributes to the reaction with the modified polyphenylene ether compound. Examples of the curing agent include styrene, 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 a maleimide group in the molecule, compounds having an acenaphthylene structure in the molecule, and isocyanurate compounds having an isocyanurate group in the molecule.

[0099] Examples of the styrene derivatives include bromostyrene and dibromostyrene.

[0100] 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.

[0101] The compound having a methacryloyl group in the molecule is a methacrylate compound. Examples of the methacrylate compound include monofunctional methacrylate compounds having one methacryloyl group in the molecule and polyfunctional methacrylate compounds 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.

[0102] 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, and a polyfunctional vinyl compound having two or more vinyl groups in the molecule. Examples of the polyfunctional vinyl compound include divinylbenzene and polybutadiene.

[0103] 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).

[0104] The compound having a maleimide group in the molecule is a maleimide compound. Examples of the maleimide compound include a monofunctional maleimide compound having one maleimide group in the molecule, a polyfunctional maleimide compound having two or more maleimide groups in the molecule, and a modified maleimide compound. Examples of the modified maleimide compound include a modified maleimide compound in which a portion of the molecule is modified with an amine compound, a modified maleimide compound in which a portion of the molecule is modified with a silicone compound, and a modified maleimide compound in which a portion of the molecule is modified with an amine compound and a silicone compound.

[0105] 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.

[0106] 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).

[0107] Among the above, preferred curing agents include, for example, polyfunctional acrylate compounds having two or more acryloyl groups in the molecule, polyfunctional methacrylate compounds having two or more methacryloyl groups in the molecule, polyfunctional vinyl compounds having two or more vinyl groups in the molecule, styrene derivatives, allyl compounds having an allyl group in the molecule, maleimide compounds having a maleimide group in the molecule, acenaphthylene compounds having an acenaphthylene structure in the molecule, and isocyanurate compounds having an isocyanurate group in the molecule.

[0108] The curing agent may be used alone or in combination of two or more kinds.

[0109] The curing agent preferably has a weight-average molecular weight of 100 to 5000, more preferably 100 to 4000, and even more preferably 100 to 3000. If the curing agent's weight-average molecular weight is too low, the curing agent may be more likely to volatilize from the resin composition's blended components. If the curing agent's weight-average molecular weight is too high, the resin composition's varnish viscosity and melt viscosity during heat molding may be too high. Therefore, when the curing agent's weight-average molecular weight is within this range, a resin composition with excellent heat resistance can be obtained. This is thought to be because the resin composition containing the modified polyphenylene ether compound can be favorably cured by reaction with the modified polyphenylene ether compound. The weight-average molecular weight may be measured using a common molecular weight measurement method, specifically, a value measured using gel permeation chromatography (GPC), etc.

[0110] The average number of functional groups per molecule of the curing agent that contribute to the reaction with the modified polyphenylene ether compound (the number of functional groups) varies depending on the weight-average molecular weight of the curing agent, but is preferably 1 to 20, and more preferably 2 to 18. If the number of 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 functional groups is too large, the reactivity becomes too high, which may cause problems such as reduced storage stability and reduced fluidity of the resin composition.

[0111] (Reaction initiator) The resin composition according to this embodiment may further contain a reaction initiator (initiator). The curing reaction can proceed even when the resin composition is composed of the modified polyphenylene ether compound and the curing agent. The curing reaction can also proceed when the resin composition contains only the modified polyphenylene ether compound. 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.

[0112] The reaction initiator is not particularly limited as long as it can accelerate the curing reaction of the modified polyphenylene ether compound (and the curing agent, if any). Specific examples include metal oxides, azo compounds, and organic peroxides.

[0113] Specific examples of metal oxides include metal carboxylates.

[0114] 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.

[0115] 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).

[0116] Among these, preferred initiators are 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(N-butyl-2-methylpropionamide), etc. These initiators have little effect on dielectric properties. In addition, because the reaction initiation temperature is relatively high, promotion of the curing reaction can be suppressed when curing is not required, such as during prepreg drying, which has the advantage of suppressing deterioration in the shelf life of the resin composition.

[0117] The above-mentioned reaction initiators may be used alone or in combination of two or more kinds.

[0118] (Inorganic filler) The resin composition according to this embodiment may further contain a filler such as an inorganic filler. Examples of fillers include those added to suppress thermal expansion and enhance flame retardancy of the cured resin composition, and are not particularly limited. Furthermore, the inclusion of a filler can further enhance heat resistance and flame retardancy. Specific examples of fillers include silica such as spherical silica, metal oxides such as alumina, titanium oxide, and mica, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, talc, aluminum borate, barium sulfate, and calcium carbonate. Among these, silica, mica, and talc are preferred, with spherical silica being more preferred. One type of filler may be used alone, or two or more types may be used in combination. The filler may be used as is, or may be surface-treated with the silane coupling agent.

[0119] It is also preferable to use silica as the inorganic filler, in which the ratio of the number of Si atoms contained in silanol groups to the total number of Si atoms is 3% or less. By incorporating silica with a low silanol group content as an inorganic filler into the resin composition of this embodiment, it is believed that a cured resin composition can be obtained that can more appropriately maintain low dielectric properties even after heat treatment. The silica has a ratio of the number of Si atoms contained in silanol groups to the total number of Si atoms of 3% or less, preferably 2.5% or less, and more preferably 2% or less. While a lower ratio is preferable, in practice, the limit is approximately 0.1%. For this reason, the ratio is preferably 0.1 to 3%.

[0120] The ratio of the number of Si atoms contained in silanol groups to the total number of Si atoms in silica can be measured without any particular limitation, as long as it is possible to measure the ratio of the number of Si atoms contained in silanol groups (Si-OH) contained in silica to the total number of Si atoms contained in silica. For example, this can be measured by obtaining a silica spectrum by solid-state 29Si-NMR measurement.

[0121] (Each content) The content of the free radical compound is preferably 0.01 to 0.4 parts by mass, more preferably 0.05 to 0.3 parts by mass, and even more preferably 0.1 to 0.2 parts by mass, relative to 100 parts by mass of the total of the modified polyphenylene ether compound and the curing agent in the resin composition. When the content of the free radical compound is within the above range, it is believed that a cured product having low dielectric properties and high heat resistance and being able to more favorably maintain its low dielectric properties even after heat treatment and / or water absorption treatment can be obtained, and a resin composition having excellent moldability can be more reliably obtained.

[0122] The content of the modified polyphenylene ether compound is preferably 10 to 95 parts by mass, more preferably 15 to 90 parts by mass, and even more preferably 20 to 90 parts by mass, relative to 100 parts by mass of the resin component (organic component) in the resin composition. That is, the content of the modified polyphenylene ether compound is preferably 10 to 95% by mass relative to the components other than the inorganic filler in the resin composition.

[0123] As described above, the resin composition may contain the curing agent. When the resin composition contains the curing agent, the content of the curing agent is, for example, preferably 5 to 50 parts by mass, more preferably 10 to 50 parts by mass, per 100 parts by mass of the resin component (organic component) in the resin composition. The content of the curing agent is also preferably 5 to 50 parts by mass, more preferably 10 to 50 parts by mass, per 100 parts by mass of the combined total of the modified polyphenylene ether compound and the curing agent.

[0124] When the contents of the modified polyphenylene ether compound and the curing agent are each within the above ranges, the cured product of the resin composition has excellent heat resistance, which is believed to be due to the favorable progress of the curing reaction between the polymer and the curing agent.

[0125] When the resin composition of this embodiment contains the reaction initiator, its content is not particularly limited. For example, it is preferably 0.5 to 8.0 parts by mass, more preferably 0.5 to 5.0 parts by mass, and even more preferably 0.5 to 2.0 parts by mass, per 100 parts by mass of the total mass of the polymer, the curing agent, and the modified polyphenylene ether compound. If the content of the reaction initiator is too low, the curing reaction between the modified polyphenylene ether compound and the curing agent tends not to start properly. If the content of the initiator is too high, the dielectric loss tangent of the cured product of the obtained prepreg tends to increase, making it difficult to exhibit excellent low dielectric properties. Therefore, if the content of the reaction initiator is within the above range, a cured prepreg with excellent low dielectric properties can be obtained.

[0126] When the resin composition of this embodiment contains the reaction initiator, the ratio of the free radical compound to the reaction initiator in the resin composition (free radical compound: reaction initiator) is preferably about 0.005:1.0 to 0.2:1.0, more preferably about 0.01:1.0 to 0.2:1.0, and even more preferably about 0.1:1.0 to 0.2:1.0. This is believed to more reliably achieve the effects of the present invention.

[0127] Furthermore, when the resin composition of the present embodiment contains an inorganic filler, the content thereof (filler content) is preferably 30 to 270 mass %, and more preferably 50 to 250 mass %, relative to the resin composition.

[0128] (Other ingredients) The resin composition according to the present embodiment may contain other components (other components) in addition to the components described above, as necessary, 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 include additives such as a reaction accelerator, a catalyst, a dispersant, a leveling agent, a silane coupling agent, a flame retardant, an antifoaming agent, an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a dye or pigment, and a lubricant. Furthermore, in addition to the modified polyphenylene ether compound, the curing agent, and the polymer, the resin composition may also contain a thermosetting resin such as polyphenylene ether or an epoxy resin.

[0129] As described above, the resin composition according to this embodiment may contain a flame retardant. The inclusion of a flame retardant can enhance the flame retardancy of the cured resin composition. The flame retardant is not particularly limited. Specifically, in fields where halogen-based flame retardants such as bromine-based flame retardants are used, for example, ethylene dipentabromobenzene, ethylene bistetrabromoimide, decabromodiphenyl oxide, and tetradecabromodiphenoxybenzene, which have melting points of 300°C or higher, are preferred. The use of halogen-based flame retardants is believed to suppress halogen elimination at high temperatures and prevent a decrease in heat resistance. Furthermore, in fields where halogen-free materials are required, phosphorus-containing flame retardants may be used. Specific examples include phosphate ester-based flame retardants, phosphazene-based flame retardants, bisdiphenylphosphine oxide-based flame retardants, and phosphinate-based flame retardants. Specific examples of phosphate ester-based flame retardants include condensed phosphate esters of dixylenyl phosphate. Specific examples of phosphazene-based flame retardants include phenoxyphosphazene. A specific example of a bisdiphenylphosphine oxide flame retardant is xylylenebisdiphenylphosphine oxide. A specific example of a phosphinate flame retardant is a metal phosphinate of an aluminum dialkylphosphinate. As the flame retardant, each of the exemplified flame retardants may be used alone or in combination of two or more.

[0130] (Manufacturing method) The method for producing the resin composition is not particularly limited, and examples thereof include a method of mixing the modified polyphenylene ether compound and the free radical compound with other components as necessary. 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.

[0131] The resin composition of this embodiment preferably has a minimum melt viscosity (T2) and a melt viscosity (T1) at a temperature 10°C above the minimum melt viscosity such that T1 / T2 is greater than 1.0 and not greater than 10.0. This is believed to have the advantage of further reducing the viscosity and making the resin composition more easily spreadable. In particular, T1 / T2 is more preferably greater than 1.0 and not greater than 5.0, and even more preferably greater than 1.0 and not greater than 1.7.

[0132] Furthermore, it is preferable that T2 is 12,000 (poise) or less and T1 is 15,000 (poise) or less. This is because it is thought that the resin composition is thereby easily filled into the pattern and moldability is improved. Furthermore, it is particularly preferable that T2 is 4,000 (poise) or less and T1 is 5,000 (poise) or less, and in particular that T2 is 1,300 (poise) or less and T1 is 1,520 (poise) or less.

[0133] Furthermore, the resin composition of this embodiment preferably has a dielectric loss tangent (10 GHz) of 0.0028 or less, and more preferably 0.0026 or less, in a cured product thereof.

[0134] Furthermore, when a cured product of the resin composition of this embodiment is subjected to moisture absorption treatment (treatment for 120 hours in an environment of a temperature of 85°C and a humidity of 85%) according to JIS C 6481 (1996) and the difference in dielectric tangent between the cured product before and after the treatment is measured, the (dielectric tangent after the moisture absorption treatment) - (dielectric tangent before the moisture absorption treatment) is preferably 0.0006 or less, and more preferably 0.0004 or less.

[0135] Furthermore, when a cured product of the resin composition of this embodiment is held (heat-treated) at 130°C for 120 hours and the difference between the dielectric loss tangent of the heat-treated cured product (dielectric loss tangent after heat treatment) and the dielectric loss tangent of the cured product before heat treatment is measured, it is preferable that (dielectric loss tangent after heat treatment) - (dielectric loss tangent before heat treatment) is 0.0012 or less, and more preferably 0.0010 or less.

[0136] Furthermore, by using the resin composition according to this embodiment, it is possible to obtain a prepreg, a metal-clad laminate, a wiring board, a resin-coated metal foil, and a resin-coated film as follows: In the following description, the respective reference numerals represent: 1 prepreg, 2 resin composition or semi-cured resin composition, 3 fibrous substrate, 11 metal-clad laminate, 12 insulating layer, 13 metal foil, 14 wiring, 21 wiring board, 31 resin-coated metal foil, 32 and 42 resin layer, 41 resin-coated film, and 43 support film.

[0137] [Prepreg] FIG. 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention.

[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 and the viscosity gradually increases. In such a case, the semi-cured state can be exemplified by the 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 if necessary. Subsequently, components that are insoluble in the organic solvent (e.g., inorganic fillers) 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, and the like and does not inhibit the curing reaction. Specific examples include toluene and methyl ethyl ketone (MEK).

[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 the form of a varnish, 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. The 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 that can be suitably used to obtain a cured product that has low dielectric properties and high heat resistance, and that can favorably maintain its low dielectric properties even after heat treatment or water absorption treatment. Furthermore, it has good moldability and, when used in wiring boards, etc., also has excellent filling properties into circuit patterns.

[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 made of 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-supported copper foil having a release layer and a carrier to improve handleability.

[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 a method in which one or more prepregs 1 are stacked, and then a metal foil 13 such as copper foil is stacked on both or one of the upper and lower surfaces of the prepreg 1, and the metal foil 13 and the prepreg 1 are heated and pressurized to form an integrated laminate, thereby producing a double-sided or single-sided metal foil-clad laminate 11. That is, the metal-clad laminate 11 is obtained by stacking the metal foil 13 on the prepreg 1 and then heating and pressurizing the resulting laminate. The heating and pressurizing 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 210°C, the pressure can be 3.5 to 4 MPa, and the time can be 60 to 150 minutes. The metal-clad laminate may 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 the present embodiment is a metal-clad laminate having an insulating layer that has low dielectric properties, high heat resistance, and can favorably maintain its low dielectric properties even after heat treatment or water absorption treatment. Furthermore, it has good formability and, when used in a wiring board or the like, has excellent filling ability into a circuit pattern.

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

[0154] As shown in Fig. 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 it can produce the wiring board 21. Specifically, a method for manufacturing the wiring board 21 using the prepreg 1 can be used. Examples of such a method include a method for manufacturing the wiring board 21 by etching the metal foil 13 on the surface of the metal-clad laminate 11 manufactured as described above to form wiring, thereby manufacturing the wiring board 21 having wiring provided as a circuit on the surface of the insulating layer 12. That is, the wiring board 21 can be 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, other methods 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 and 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 having an insulating layer with low dielectric properties and high heat resistance, and capable of favorably maintaining its low dielectric properties even after heat treatment or water absorption treatment. Furthermore, the resin composition of this embodiment has good moldability and exhibits good filling properties even in circuit patterns on wiring boards. Therefore, it has the advantage of being usable in wiring boards in which the distance between conductor circuits (wiring) is narrow. The resin composition of this embodiment is not particularly limited, but can also be suitably used in wiring boards in which a conductor circuit pattern is provided in which the distance between conductor circuits is at least partially, for example, 50 μm or less.

[0157] In particular, the wiring board of this embodiment may be a multilayer wiring board having two or more circuit layers, and the resin composition of this embodiment can be suitably used as an interlayer insulating material for the multilayer wiring board. Although not particularly limited, the wiring board may be, for example, a multilayer wiring board having two or more circuit layers and a wiring pattern in which the distance between the wirings is 50 μm or less in at least a portion thereof. Furthermore, for example, a wiring pattern in which the distance between the wirings is 30 μm or less in at least a portion thereof may be provided.

[0158] Furthermore, the resin composition of this embodiment is preferably used as an insulating material for the insulating layer of a highly multilayer wiring board having five or more circuit layers, or even ten or more circuit layers, although this is not particularly limited. In the manufacture of a highly multilayer wiring board having five or more circuit layers, or even ten or more circuit layers, the interlayer insulating material of this embodiment can be used to stably embed each inner layer circuit in the multilayering process of forming each interlayer insulating layer, ensuring excellent moldability. By ensuring excellent moldability, separation at the adhesive surface between the inner layer circuit of the multilayer wiring board and the interlayer insulating layer can be prevented when a highly multilayer wiring board having five or more circuit layers, or even ten or more circuit layers, is subjected to high-temperature treatment after absorbing moisture, for example.

[0159] [Metal foil with resin] FIG. 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil 31 according to this embodiment.

[0160] 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.

[0161] 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, but 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.

[0162] The metal foil may be any metal foil used in metal-clad laminates, including, for example, copper foil and aluminum foil.

[0163] 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.

[0164] 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) onto the metal foil 13 and heating it. The varnish-like resin composition is applied onto the metal foil 13, for example, 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 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.

[0165] 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 be used to obtain a cured product that has low dielectric properties and high heat resistance and can maintain its low dielectric properties even after heat treatment or water absorption treatment. Furthermore, it has good formability and, when used in wiring boards, etc., has excellent filling properties into circuit patterns. For example, by laminating it on a wiring board, a multilayer wiring board can be produced.

[0166] [Resin-coated film] FIG. 5 is a schematic cross-sectional view showing an example of a resin-coated film 41 according to the present embodiment.

[0167] 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.

[0168] 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 include a resin layer containing a semi-cured product of the resin composition (the resin composition in B stage) and a support film, or may be a resin-coated film including 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.

[0169] 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.

[0170] The resin-coated film 41 may be provided with a cover film or the like as needed. 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.

[0171] 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.

[0172] 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 a temperature of 80°C to 180°C for 1 minute to 10 minutes. The heated resin composition is formed on the support film 43 as an uncured resin layer 42. The heating volatilizes the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0173] A resin-coated film 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 film that can be used to obtain a cured product that has low dielectric properties and high heat resistance and can favorably maintain its low dielectric properties even after heat treatment or water absorption treatment. Furthermore, it has good formability and, when used in wiring boards, etc., has excellent filling properties into circuit patterns. For example, a multilayer wiring board can be produced by laminating the resin composition on a wiring board and then peeling off the support film, or by laminating the resin composition on a wiring board after peeling off the support film.

[0174] 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. [Example]

[0175] [Examples 1 to 15 and Comparative Examples 1 to 5] In this example, each component used in preparing the resin composition will be described.

[0176] (PPE component) Modified PPE1: Modified polyphenylene ether in which the terminal hydroxyl group of polyphenylene ether is modified with a methacrylic group (represented by the above formula (19), in which Y in formula (19) is a dimethylmethylene group (represented by formula (16), in which R33 and R 34 modified polyphenylene ether compound (wherein each methyl group is a group), SA9000 manufactured by SABIC Innovative Plastics, weight average molecular weight Mw 2000, number of terminal functional groups 2)

[0177] Modified PPE2: Modified PPE2 is obtained by reacting polyphenylene ether with chloromethylstyrene. Specifically, it is a modified PPE obtained by the following reaction:

[0178] First, 200 g of polyphenylene ether (SA90 manufactured by SABIC Innovative Plastics, 2 terminal hydroxyl groups, weight-average molecular weight Mw 1700), 30 g of a 50:50 mass ratio mixture of p-chloromethylstyrene and m-chloromethylstyrene (chloromethylstyrene: CMS manufactured by Tokyo Chemical Industry Co., Ltd.), 1.227 g of tetra-n-butylammonium bromide as a phase transfer catalyst, and 400 g of toluene were charged into a 1-liter three-neck flask equipped with a temperature controller, stirrer, cooling equipment, and dropping funnel, and the mixture was stirred. The mixture was then stirred until the polyphenylene ether, chloromethylstyrene, and tetra-n-butylammonium bromide were dissolved in the toluene. The mixture was gradually heated until the liquid temperature reached 75°C. An aqueous sodium hydroxide solution (20 g sodium hydroxide / 20 g water) was added dropwise to the solution as an alkali metal hydroxide over 20 minutes. The mixture was then stirred at 75°C for an additional 4 hours. Next, the contents of the flask were neutralized with 10% by mass of hydrochloric acid, and then a large amount of methanol was added. This caused a precipitate to form in the liquid in the flask. In other words, the product contained in the reaction solution in the flask was reprecipitated. This precipitate was then filtered, washed three times with a mixture of methanol and water in an 80:20 mass ratio, and then dried under reduced pressure at 80°C for 3 hours.

[0179] The obtained solid is 1The solid was analyzed by H-NMR (400 MHz, CDCl3, TMS). As a result of NMR measurement, a peak derived from a vinylbenzyl group (ethenylbenzyl group) was confirmed at 5 to 7 ppm. This confirmed that the obtained solid was a modified polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) as the substituent at the molecular end in the molecule. Specifically, it was confirmed that it was an ethenylbenzylated polyphenylene ether. The obtained modified polyphenylene ether compound is represented by the above formula (18), in which Y is a dimethylmethylene group (represented by formula (16), and R in formula (16) 33 and R 34 is a methyl group), Z is a phenylene group, R1 to R3 are hydrogen atoms, n is 1, and p is 1.

[0180] The number of terminal functional groups of the modified polyphenylene ether was measured as follows.

[0181] First, the modified polyphenylene ether was accurately weighed. The weight at that time was designated X (mg). Then, this weighed modified polyphenylene ether was dissolved in 25 mL of methylene chloride, and 100 μL of a 10 mass% ethanol solution of tetraethylammonium hydroxide (TEAH) (TEAH:ethanol (volume ratio) = 15:85) was added to the solution, and the absorbance (Abs) at 318 nm was measured using a UV spectrophotometer (UV-1600, manufactured by Shimadzu Corporation). Then, from the measurement results, the number of terminal hydroxyl groups of the modified polyphenylene ether was calculated using the following formula.

[0182] Residual OH amount (μmol / g) = [(25×Abs) / (ε×OPL×X)]×10 6 where ε is the extinction coefficient, 4700 L / mol cm, and OPL is the cell path length, 1 cm.

[0183] The calculated residual OH amount (number of terminal hydroxyl groups) of the modified polyphenylene ether was almost zero, which indicated that the hydroxyl groups of the polyphenylene ether before modification were almost entirely modified. This indicated that the decrease in the number of terminal hydroxyl groups from the polyphenylene ether before modification was the number of terminal hydroxyl groups of the polyphenylene ether before modification. In other words, it was found that the number of terminal hydroxyl groups of the polyphenylene ether before modification was the number of terminal functional groups of the modified polyphenylene ether. In other words, the number of terminal functional groups was two.

[0184] The intrinsic viscosity (IV) of the modified polyphenylene ether was measured in methylene chloride at 25°C. Specifically, the intrinsic viscosity (IV) of the modified polyphenylene ether was measured using a viscometer (AVS500 Visco System manufactured by Schott) for a 0.18 g / 45 ml methylene chloride solution (liquid temperature 25°C) of the modified polyphenylene ether. As a result, the intrinsic viscosity (IV) of the modified polyphenylene ether was 0.086 dL / g.

[0185] The molecular weight distribution of the modified polyphenylene ether was measured using GPC. The weight average molecular weight (Mw) was calculated from the obtained molecular weight distribution. As a result, Mw was 2,300.

[0186] (hardening agent) Acenaphthylene: Acenaphthylene manufactured by JFE Chemical Corporation Maleimide compound: N-phenylmonomaleimide manufactured by Nippon Shokubai Co., Ltd. Isocyanurate compound: triallyl isocyanurate (TAIC) manufactured by Mitsubishi Chemical Corporation

[0187] (Reaction initiator) Azo initiator: Fujifilm Wako Pure Chemical Industries, Ltd. "VR-110" Peroxide initiator: PBP (1,3-bis(butylperoxyisopropyl)benzene; Perbutyl P manufactured by NOF Corporation)

[0188] (free radical compounds) Free radical compound 1: A free radical compound represented by the following formula ("H0865" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0189] [ka]

[0190] Free radical compound 2: A free radical compound represented by the following formula ("T3751" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0191] [ka]

[0192] Free radical compound 3: A free radical compound represented by the following formula ("H0878" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0193] [ka]

[0194] Free radical compound 4: A free radical compound represented by the following formula ("B5642" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0195] [ka]

[0196] Free radical compound 5: A free radical compound represented by the following formula ("C1406" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0197] [ka]

[0198] Free radical compound 6: A free radical compound represented by the following formula ("D4313" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0199] [ka]

[0200] Free radical compound 7: A free radical compound represented by the following formula ("G0020" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0201] [ka]

[0202] (catechol compounds) 4-tert-Butylcatechol: 4-tert-Butylcatechol manufactured by Tokyo Chemical Industry Co., Ltd.

[0203] (Inorganic filler) Silica filler 1: Admatechs' "SC-2300SVJ" (silica with 4.0% silanol group content) Silica filler 2: "5SV-C5" manufactured by Admatechs (silica with 1.0% silanol group content)

[0204] (Preparation method) First, the above components except for the inorganic filler were added to toluene and mixed in the composition (parts by mass) shown in Table 1 so that the solids concentration was 55% by mass. The mixture was stirred for 60 minutes. Thereafter, the inorganic filler was added to the resulting liquid, and the filler was dispersed using a bead mill. This resulted in a varnish-like resin composition (varnish).

[0205] [Melt viscosity] 0.5 g of the powdery, semi-cured resin composition obtained from the prepreg was pressed under a pressure of 2.8 MPa into a pellet with a diameter of 1.0 cm and a height of 0.5 cm to prepare a measurement sample. The melting behavior of the measurement sample was measured using a Rheosol G3000NT dynamic viscoelasticity measuring device. The measurement conditions included increasing the sample temperature at a rate of 4 degrees per minute, and measuring the viscosity of the sample during this period. The temperature at which the measured viscosity decreased the most during the temperature increase process from the semi-cured state (B stage) to the cured state (C stage) was defined as the minimum melt viscosity (T2).

[0206] [T1 / T2] The melt viscosity when the temperature was raised by 10°C from the minimum melt viscosity (T2) was defined as T1, and T1 / T2 was calculated. T1 / T2 is an index for measuring the curing speed from the state where T2 was reached once during the temperature rise (the state where the viscosity is at its lowest), and a smaller T1 / T2 value indicates a slower curing speed, which is considered to be one of the characteristics of a resin composition with high moldability.

[0207] Next, an evaluation substrate (cured prepreg) was obtained as follows.

[0208] The resulting varnish was impregnated into a fibrous substrate (glass cloth: Asahi Kasei Corporation's 1078L, #1078 type, L glass) and then heated and dried at 120°C for 3 minutes to produce a prepreg. The resin content of the components that make up the resin through the curing reaction was adjusted to 67% by mass. Two of the resulting prepregs were then stacked and heated and pressurized at 200°C for 2 hours at a pressure of 3 MPa to produce an evaluation substrate (cured prepreg).

[0209] Next, an evaluation substrate (metal-clad laminate) was obtained as follows.

[0210] A fibrous substrate (glass cloth: Asahi Kasei Corporation's GC1078L, #1078 type, L glass) was impregnated with the varnish and then heated and dried for 2 minutes at 110°C to produce a prepreg. The content of the components that make up the resin by the curing reaction (resin content) relative to the prepreg was adjusted to 67% by mass.

[0211] Two sheets of each prepreg were stacked on top of each other, and copper foil (FV-WS, 18 μm thick, manufactured by Furukawa Electric Co., Ltd.) was placed on both sides to form a pressure body. The body was heated and pressed at a temperature of 200°C and a pressure of 3 MPa for 2 hours to produce a copper foil-clad laminate, an evaluation substrate (metal-clad laminate) with copper foil bonded to both sides.

[0212] The evaluation substrates (cured prepreg and metal-clad laminate) prepared as described above were evaluated by the following methods.

[0213] [Moldability] A 200mm x 200mm cured product with a grid-like copper pattern, 80% copper residual, and 35μm line thickness, was prepared. A 200mm x 200mm prepreg was layered on top of this. A 250mm x 250mm copper foil with a thickness of 35μm was layered on top of this. These were sandwiched between metal plates approximately 3mm thick and heated and pressurized using a laminate molding press under the following conditions. The heating conditions were a rate of 4°C per minute from 30°C to 200°C. The pressure applied to the prepreg was set to 1MPa at the start of heating, and then, when the temperature reached 110°C, the pressure applied to the prepreg was increased to 3MPa, allowing the prepreg to cure.

[0214] As a result, if no gaps were generated between the grid pattern and the cured product and the product was filled, it was evaluated as "Good", and if gaps were generated, it was evaluated as "Poor." The presence or absence of gaps was determined by removing the copper foil from the cured product produced using a laminate molding press and shining light through it from the other side, and checking whether whitish gaps could be confirmed.

[0215] [Dielectric loss tangent before moisture absorption treatment] The dielectric loss tangent of the evaluation board (cured prepreg) at 10 GHz was measured using the cavity resonator perturbation method. Specifically, a network analyzer (Keysight Technologies N5230A) was used to measure the dielectric loss tangent of the evaluation board at 10 GHz.

[0216] [Dielectric loss tangent after moisture absorption treatment] The evaluation board used in measuring the dielectric loss tangent before the moisture absorption treatment was subjected to a moisture absorption treatment in accordance with JIS C 6481 (1996), and the dielectric loss tangent of this moisture-treated evaluation board (dielectric loss tangent after moisture absorption) was measured in the same manner as in measuring the dielectric loss tangent before the moisture absorption treatment. Note that the moisture absorption treatment involved treating the evaluation board in an environment of a temperature of 85°C and a humidity of 85% for 120 hours, after which the moisture on the evaluation board was thoroughly wiped off with a dry, clean cloth, and the measurement was then performed.

[0217] [Change in dielectric tangent (after moisture absorption treatment - before moisture absorption treatment)] The difference between the dielectric loss tangent before the moisture absorption treatment and the dielectric loss tangent after the moisture absorption treatment (dielectric loss tangent after the moisture absorption treatment - dielectric loss tangent before the moisture absorption treatment) was calculated.

[0218] [Dielectric loss tangent before heat treatment] The dielectric loss tangent of the evaluation board at 10 GHz was measured using the cavity resonator perturbation method. Specifically, a network analyzer (Keysight Technologies N5230A) was used to measure the dielectric loss tangent of the evaluation board at 10 GHz.

[0219] [Dielectric loss tangent after heat treatment] The evaluation substrate used in the measurement of the dielectric loss tangent before the heat treatment was held (heat treated) at 130°C for 120 hours, and the dielectric loss tangent of this heat-treated evaluation substrate (dielectric loss tangent after the heat treatment) was measured in the same manner as in the measurement of the dielectric loss tangent before the heat treatment.

[0220] [Change in dielectric tangent (after heat treatment - before heat treatment)] The difference between the dielectric loss tangent before and after the heat treatment (=dielectric loss tangent after the heat treatment−dielectric loss tangent before the heat treatment) was calculated.

[0221] [Glass transition temperature (DMA) (Tg)] The Tg of the cured product was measured using a viscoelasticity spectrometer "DMS6100" manufactured by Seiko Instruments Inc. Dynamic viscoelasticity measurement (DMA) was performed using a bending module at a frequency of 10 Hz, and the temperature at which tan δ reached a maximum when the temperature was raised from room temperature to 320°C at a heating rate of 5°C / min was defined as Tg.

[0222] The results of the above evaluations are shown in Table 1.

[0223] [Table 1]

[0224] (Consideration) As can be seen from Table 1, in all of the examples in which the resin composition of the present invention was used, it was possible to obtain a cured product that had low dielectric properties, high heat resistance, and was less susceptible to the effects of changes in the external environment, and it was confirmed that a resin composition with moldability that could be used in laminated wiring boards could be provided.

[0225] On the other hand, in Comparative Examples 1 to 3, which did not contain a free radical compound, the low dielectric properties could not be maintained due to the influence of changes in the external environment. Furthermore, in Comparative Example 1, which did not contain a free radical compound or a reaction initiator, hardening began quickly after the minimum melting, resulting in poor moldability. In Comparative Examples 2 and 3, as in Comparative Example 1, hardening also progressed quickly after the minimum melting due to the effect of the addition of the reaction initiator, resulting in poor moldability.

[0226] This application is based on Japanese Patent Application No. 2019-177946, filed on September 27, 2019, the contents of which are incorporated herein by reference.

[0227] 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. [Industrial Applicability]

[0228] The present invention has wide industrial applicability in the technical fields related to electronic materials and various devices using the same.

Claims

1. A resin composition used to form an insulating layer of a metal-clad laminate or a wiring board, comprising: The composition contains a modified polyphenylene ether compound terminally modified with a substituent having a carbon-carbon unsaturated double bond, and a free radical compound, The free radical compound has at least one free radical group selected from the group of structures represented by the following formulas (1), (2), (3), and (4) in the molecule, and also contains at least one compound selected from the compounds represented by the following formulas (7) to (9). 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 【Transformation 7】 【Transformation 8】 【Chemistry 9】 (In formula (7), X Ａ represents an amino group, a cyano group, a hydroxy group, an isothiocyanate group, a methoxy group, a carboxy group, an amide group, or a benzoyloxy group. In formula (8), X Ｂ represents a hydrogen atom, an amino group, a cyano group, a hydroxy group, an isothiocyanate group, a methoxy group, a carboxy group, an amido group, or a benzoyloxy group. In formula (9), X Ｃ represents an alkylene group, an aromatic structure, a carbonyl group, or an ether bond.

2. The resin composition according to claim 1, wherein in the modified polyphenylene ether compound (A), the substituent includes at least one selected from groups represented by the following formula (5) or formula (6): 【Transformation 5】 (In formula (5), p represents an integer of 0 to 10. Z represents an arylene group. R １ ~R ３ each independently represents a hydrogen atom or an alkyl group. 【Transformation 6】 (In formula (6), R ４ represents a hydrogen atom or an alkyl group.

3. The resin composition according to claim 1 or 2, further comprising a curing agent.

4. The resin composition according to claim 3, wherein the content of the free radical compound is 0.01 to 0.4 parts by mass per 100 parts by mass of the total of the modified polyphenylene ether compound and the curing agent.

5. 5. The resin composition according to claim 3, wherein the curing agent comprises at least one selected from the group consisting of a polyfunctional acrylate compound having two or more acryloyl groups in the molecule, a polyfunctional methacrylate compound having two or more methacryloyl groups in the molecule, a polyfunctional vinyl compound having two or more vinyl groups in the molecule, bromostyrene, dibromostyrene, an allyl compound having an allyl group in the molecule, a maleimide compound having a maleimide group in the molecule, an acenaphthylene compound having an acenaphthylene structure in the molecule, and an isocyanurate compound having an isocyanurate group in the molecule.

6. The resin composition according to claim 1 or 2, further comprising a reaction initiator.

7. The resin composition according to claim 3 or 4, further comprising a reaction initiator.

8. The resin composition according to claim 6 or 7, wherein the reaction initiator comprises at least one selected from the group consisting of a metal peroxide, an azo compound, and an organic peroxide.

9. 7. The resin composition according to claim 6, wherein the content of the reaction initiator is 0.5 to 8.0 parts by mass per 100 parts by mass of the total of the modified polyphenylene ether compounds.

10. 8. The resin composition according to claim 7, wherein the content of the reaction initiator is 0.5 to 8.0 parts by mass per 100 parts by mass of the total of the modified polyphenylene ether compound and the curing agent.

11. The resin composition according to any one of claims 6 to 10, wherein the ratio (mass ratio) of the free radical compound to the reaction initiator is 0.005:1.0 to 0.2:1.

0.

12. The resin composition according to any one of claims 1 to 11, further comprising an inorganic filler.

13. A prepreg comprising the resin composition according to any one of claims 1 to 11 or a semi-cured product of the resin composition and a fibrous base material.

14. A resin-coated film comprising a resin layer containing the resin composition according to any one of claims 1 to 11 or a semi-cured product of the resin composition, and a support film.

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

16. A metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 11 or a cured product of the prepreg according to claim 13, and a metal foil.

17. A wiring board comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 11 or a cured product of the prepreg according to claim 13, and wiring.

18. The wiring board according to claim 17 , wherein the wiring board has a plurality of insulating layers, and the wiring is disposed between the insulating layers.

19. The resin composition according to any one of claims 1 to 11, wherein the minimum melt viscosity (T2) and the melt viscosity (T1) at a temperature 10°C higher than the minimum melt viscosity temperature are such that T1 / T2 is greater than 1.0 and 10.0 or less.

20. The resin composition according to claim 19, wherein T2 is 12,000 (poise) or less and T1 is 15,000 (poise) or less.

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