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

Abstract

One aspect of the present invention is a resin composition including: a linear copolymer (A) that includes a repeating unit (a1) derived from a monovinyl aromatic compound and having a prescribed structure, a repeating unit (a2) derived from a divinyl aromatic compound, and a repeating unit (a3) derived from an aromatic ring-condensed cyclic olefin compound and having a prescribed structure; and a copolymer (B) that includes a repeating unit (b1) derived from a monovinyl aromatic compound and a repeating unit (b2) derived from a divinyl aromatic compound, and does not include a repeating unit derived from an aromatic ring-condensed cyclic olefin compound and having a prescribed structure.

Description

Resin compositions, prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates, and wiring boards 【0001】 The present invention relates to resin compositions, prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates, and wiring boards. 【0002】 In response to the increasing amount of information processing and the acceleration of information communication, integration technologies for various electronic devices are advancing, including the high integration of semiconductor devices, high density of wiring, and multilayering. Furthermore, the wiring boards used in various electronic devices are required to be high-frequency compatible, such as server boards for communication infrastructure equipment such as network equipment, servers, and AI (artificial intelligence) processors, and millimeter-wave radar boards for automotive applications. The substrate material that constitutes the insulating layer of the wiring boards used in various electronic devices is required to have low dielectric properties such as relative permittivity and dielectric loss tangent in order to increase the signal transmission speed and reduce signal loss during signal transmission. 【0003】 Examples of substrate materials for forming the insulating layer of such a wiring board include the compositions described in Patent Documents 1 and 2. 【0004】 Patent Document 1 describes a thermosetting composition comprising a linear copolymer having repeating units corresponding to monovinyl aromatic compounds, repeating units corresponding to divinyl aromatic compounds, and repeating units corresponding to aromatic ring-condensed cyclic olefin compounds. According to Patent Document 1, it is possible to achieve both dielectric properties and a glass transition temperature, and the melt viscosity is low. 【0005】 Patent Document 2 describes a curable resin composition containing a modified polyphenylene ether in which the hydroxyl groups at the ends of the main chain are modified with a (meth)acrylic acid-based compound, and a polyfunctional vinyl aromatic copolymer containing repeating units derived from a divinyl aromatic compound and repeating units derived from a monovinyl aromatic compound. Patent Document 2 discloses that it is possible to obtain a cured product or molded article with improved heat resistance, compatibility, dielectric properties, moist heat reliability, and resistance to thermal oxidative degradation. 【0006】For the substrate material constituting the insulating layer of the wiring board, it is also required that a cured product can be obtained which has low dielectric properties even after heating and in which variations due to temperature changes in dielectric properties and mass are suppressed. 【0007】 Japanese Patent No. 7440684 Japanese Unexamined Patent Application Publication No. 2018 - 168347 【0008】 The present invention has been made in view of such circumstances, and an object thereof is to provide a resin composition from which a cured product can be obtained which has low dielectric properties even after heating and in which variations due to temperature changes in dielectric properties and mass are suppressed. Another object of the present invention is to provide a prepreg, a resin film, a metal foil with resin, a metal-clad laminate, and a wiring board obtained using the above resin composition. 【0009】 One aspect of the present invention is a linear copolymer (A) containing a repeating unit (a1) represented by the following formula (1), a repeating unit (a2) derived from a divinyl aromatic compound, and a repeating unit (a3) represented by the following formula (2), and a copolymer (B) containing a repeating unit (b1) derived from a monovinyl aromatic compound and a repeating unit (b2) derived from a divinyl aromatic compound and not containing the repeating unit represented by the following formula (2). 【0010】 【0011】 In formula (1), R １ represents a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. 【0012】 【0013】 In formula (2), R ２ and R ３ each independently represent an alkyl group having 1 to 20 carbon atoms, a halogen atom, an aryl group having 6 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms, and m and n each independently represent 0 to 3. 【0014】 The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings. 【0015】Figure 1 is a schematic cross-sectional view showing an example of a prepreg according to an embodiment of the present invention. Figure 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 is a schematic cross-sectional view showing an example of a wiring board according to an embodiment of the present invention. Figure 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 is a schematic cross-sectional view showing an example of a resin-coated film according to an embodiment of the present invention. 【0016】 Wiring boards used in various electronic devices are required to be less susceptible to changes in the external environment. For example, the insulating layer of a wiring board tends to exhibit dielectric properties that change with temperature, such as an increase in dielectric loss tangent when heated. Therefore, the insulating layer of a wiring board is required to have low dielectric properties, such as dielectric loss tangent, even after heating, and to have dielectric properties that do not easily change with temperature, so that the wiring board can be used even in relatively high-temperature environments. Accordingly, the substrate material constituting the insulating layer of a wiring board is required to be a cured product that maintains a low dielectric loss tangent even when heated, that is, a cured product that has low dielectric properties, such as dielectric loss tangent, even after heating, and in which changes in dielectric properties due to temperature changes are suppressed. Furthermore, the insulating layer of a wiring board is required not to develop defects such as blistering due to heating during reflow soldering or other processes during mounting. Therefore, it is required that the mass does not easily decrease due to heating. Accordingly, the insulating layer of a wiring board is required to have mass that does not easily change with temperature, so that the wiring board can be used even in relatively high-temperature environments. In other words, the insulating layer of the wiring board requires a high temperature to reach a predetermined mass reduction rate, and a low mass reduction rate at that predetermined temperature. Therefore, the substrate material constituting the insulating layer of the wiring board is required to produce a cured product in which mass fluctuations due to temperature changes, such as mass reduction due to thermal decomposition, are suppressed. 【0017】With conventional compositions, it has been difficult to obtain a cured product that maintains a low dielectric loss tangent even when heated, while also suppressing mass loss due to thermal decomposition. Specifically, according to the inventors' research, it was difficult to sufficiently suppress the thermal decomposition of the cured product with the thermosetting composition described in Patent Document 1. Furthermore, with the curable resin composition described in Patent Document 2, it was difficult to sufficiently suppress the decrease in dielectric loss tangent when the cured product was heated. 【0018】 As a result of various studies, the inventors have found that the above objective of providing a resin composition that yields a cured product with low dielectric properties even after heating, and in which fluctuations in dielectric properties and mass due to temperature changes are suppressed, can be achieved by the present invention as described below. 【0019】 The embodiments of the present invention will be described below, but the present invention is not limited thereto. 【0020】 [Resin Composition] The resin composition according to the embodiment of the present invention is a resin composition containing a linear copolymer (A) comprising a repeating unit (a1) represented by the following formula (1), a repeating unit (a2) derived from a divinyl aromatic compound, and a repeating unit (a3) ​​represented by the following formula (2), and a copolymer (B) comprising a repeating unit (b1) derived from a monovinyl aromatic compound and a repeating unit (b2) derived from a divinyl aromatic compound, but without the repeating unit represented by the following formula (2). By curing the resin composition, a cured product is obtained in which dielectric properties are low even after heating, and fluctuations in dielectric properties and mass due to temperature changes are suppressed. 【0021】 【0022】 In formula (1), R １ This represents a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. 【0023】 【0024】 In formula (2), R ２ and R ３Each of these independently represents an alkyl group having 1 to 20 carbon atoms, a halogen atom, an aryl group having 6 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms, and m and n independently represent 0 to 3. 【0025】 (Copolymer (A)) The copolymer (A) is not particularly limited as long as it is a linear copolymer containing the repeating unit (a1), the repeating unit (a2), and the repeating unit (a3). 【0026】 - Repeating unit (a1) The repeating unit (a1) is a constituent unit of the copolymer (A) and is not particularly limited as long as it is a repeating unit represented by formula (1). Examples of the repeating unit (a1) include a repeating unit represented by formula (1) having a structure formed by addition polymerization of a monovinyl aromatic compound as a monomer. The repeating unit (a1) is not limited to one formed by polymerization using a monovinyl aromatic compound, as long as it is a repeating unit represented by formula (1), but may also be a repeating unit represented by formula (1) formed by further reaction after polymerization. 【0027】 Examples of the repeating unit (a1) include the repeating unit represented by formula (1) having a structure in which the vinyl groups of a monovinyl aromatic compound are single-bonded by addition polymerization. 【0028】 The aforementioned R １ As described above, is a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms, and preferably a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms. The aromatic hydrocarbon group is not particularly limited as long as it is a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms, and preferably, for example, is a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms consisting only of carbon atoms and hydrogen atoms. １Examples thereof include monovalent aromatic hydrocarbon groups having 6 to 30 carbon atoms (preferably 6 to 20 carbon atoms) selected from the group consisting of a phenyl group which may have a substituent, a biphenylyl group which may have a substituent, a naphthyl group which may have a substituent, and a terphenylyl group which may have a substituent. Examples of the substituent include an alkyl group such as a methyl group and an ethyl group. Here, R １ When having a substituent such as an alkyl group, the number of carbon atoms of R １ is the total number of carbon atoms including the carbon atoms contained in the substituent. 【0029】 The monovinyl aromatic compound used when forming the repeating unit (a1) is not particularly limited as long as it has one vinyl group and can form the repeating unit represented by the formula (1) by polymerization. Examples of the monovinyl aromatic compound include vinyl aromatic compounds such as styrene, vinyl naphthalene, and vinyl biphenyl, alkyl styrenes (for example, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, and p-ethylstyrene, etc.), dialkyl styrenes (for example, 3,5-dimethylstyrene, 2,5-dimethylstyrene, and 2,5-diethylstyrene, etc.), alkyl vinyl biphenyls (for example, ethyl vinyl biphenyl, etc.), and alkyl vinyl naphthalenes (for example, ethyl vinyl naphthalene, etc.), and other nuclear alkyl-substituted vinyl aromatic compounds. These monovinyl aromatic compounds may be used alone or in combination of two or more. 【0030】The monovinyl aromatic compound preferably includes at least one selected from the group consisting of styrene, vinylnaphthalene, vinylbiphenyl, alkylstyrene, dialkylstyrene, alkylvinylbiphenyl, and alkylvinylnaphthalene. That is, the repeating unit (a1) preferably includes a repeating unit (a1-1) derived from at least one selected from the group consisting of styrene, vinylnaphthalene, vinylbiphenyl, alkylstyrene, dialkylstyrene, alkylvinylbiphenyl, and alkylvinylnaphthalene. The content of the repeating unit (a1-1) is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and may be 100 mol% relative to the repeating unit (a1) (when the repeating unit (a1) is 100 mol%). That is, the repeating unit (a1) may consist of the repeating unit (a1-1). 【0031】 The monovinyl aromatic compound preferably contains styrene. That is, the repeating unit (a1) preferably contains repeating units derived from styrene (styrene units). The content of the styrene units is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and may be 100 mol%, relative to the repeating unit (a1) (when the repeating unit (a1) is 100 mol%). That is, the repeating unit (a1) may consist of the styrene units. 【0032】- Repeating unit (a2) The repeating unit (a2) is a constituent unit of the copolymer (A) and is not particularly limited as long as it is a repeating unit derived from a divinyl aromatic compound. An example of the repeating unit (a2) is a repeating unit having a structure with one vinyl group, formed by addition polymerization of a divinyl aromatic compound as a monomer. The repeating unit (a2) is not limited to one formed by polymerization using a divinyl aromatic compound, as long as it has the above structure, and may also be a repeating unit in which the above structure is formed by further reaction after polymerization. 【0033】 The repeating unit (a2) mentioned above is a repeating unit represented by the following formula (3), which has a structure in which one vinyl group of a divinyl aromatic compound is bonded by addition polymerization. 【0034】 【0035】 In formula (3), R ４ R represents a divalent aromatic hydrocarbon group. The aromatic hydrocarbon group is preferably a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms, and more preferably a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms. ４ Examples include divalent aromatic hydrocarbon groups having 6 to 30 carbon atoms (preferably 6 to 20 carbon atoms) selected from the group consisting of optionally substituted phenylene groups, optionally substituted biphenyldiyl groups, optionally substituted naphthylene groups, and optionally substituted terphenyldiyl groups. Here, R ４ The number of carbon atoms in R includes the number of carbon atoms in the substituent, if it has substituents such as alkyl groups. ４ This is the total number of carbon atoms. 【0036】The divinyl aromatic compound used to form the repeating unit (a2) is not particularly limited as long as it is an aromatic compound having two vinyl groups. Examples of the divinyl aromatic compound include divinylbenzene (including each positional isomer or mixtures thereof), divinylnaphthalene (including each positional isomer or mixtures thereof), and divinylbiphenyl (including each positional isomer or mixtures thereof). The divinyl aromatic compound may be used individually or in combination of two or more. 【0037】 The divinyl aromatic compound preferably includes at least one selected from the group consisting of divinylbenzene, divinylnaphthalene, and divinylbiphenyl. That is, the repeating unit (a2) preferably includes a repeating unit (a2-1) derived from at least one selected from the group consisting of divinylbenzene, divinylnaphthalene, and divinylbiphenyl. The content of the repeating unit (a2-1) is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and may be 100 mol%, relative to the repeating unit (a2) (when the repeating unit (a2) is 100 mol%). That is, the repeating unit (a2) may consist of the repeating unit (a2-1). 【0038】 The divinyl aromatic compound preferably includes divinylbenzene (m-isomer, p-isomer, or a mixture of their positional isomers). That is, the repeating unit (a2) preferably contains repeating units derived from divinylbenzene (divinylbenzene units). The content of the divinylbenzene units is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and may be 100 mol%, relative to the repeating unit (a2) (when the repeating unit (a2) is 100 mol%). That is, the repeating unit (a2) may consist of the divinylbenzene units. 【0039】- Repeating unit (a3) ​​The repeating unit (a3) ​​is a constituent unit of the copolymer (A) and is not particularly limited as long as it is a repeating unit represented by formula (2). Examples of the repeating unit (a3) ​​include the repeating unit represented by formula (2) having a structure formed by addition polymerization of an aromatic ring-condensed cyclic olefin compound as a monomer. The repeating unit (a3) ​​is not limited to one formed by polymerization using an aromatic ring-condensed cyclic olefin compound, as long as it is a repeating unit represented by formula (2), but may also be a repeating unit represented by formula (2) formed by further reaction after polymerization. 【0040】 The aforementioned R ２ and R ３ Each of these is independently an alkyl group having 1 to 20 carbon atoms, a halogen atom, an aryl group having 6 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. The values ​​of m and n are independently 0 to 3. When m is 2 or more, one repeating unit contains the R ２ There are two or more of these, and they may be the same or different. Also, if n is 2 or more, one repeating unit contains the R ３ There are two or more of these, and they may be the same or different. 【0041】 The aromatic ring-condensed cyclic olefin compound used to form the repeating unit (a3) ​​is an acenaphthylene compound represented by the following formula (4). 【0042】 【0043】 In equation (4), R ２ , R ３ , m, and n are R in equation (2). ２ , R ３ It is the same as m and n. 【0044】Examples of the acenaphthylene compound include at least one selected from the group consisting of acenaphthylene, acenaphthylene having an alkyl group with 1 to 20 carbon atoms (alkylacenaphthylene), halogenated acenaphthylene, acenaphthylene having an aryl group with 6 to 20 carbon atoms (arylacenaphthylene), and acenaphthylene having an alkoxy group with 1 to 20 carbon atoms (alkoxyacenaphthylene). 【0045】 The aromatic ring-condensed cyclic olefin compound is the acenaphthylene compound, and preferably contains acenaphthylene. That is, the repeating unit (a3) ​​preferably contains repeating units (acenaphthylene units) derived from acenaphthylene. The content of the acenaphthylene units is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and may be 100 mol%, relative to the repeating unit (a3) ​​(when the repeating unit (a3) ​​is 100 mol%). That is, the repeating unit (a3) ​​may consist of the acenaphthylene units. 【0046】 The copolymer (A) is a linear copolymer comprising the repeating unit (a1), the repeating unit (a2), and the repeating unit (a3). The linear structure of copolymer (A) causes entanglement of molecular chains, improving its moldability. Here, linear means that the repeating units constituting the copolymer are linked to each other in a one-dimensional chain and do not have a cross-linking structure. 【0047】 In the copolymer (A), the repeating units (a1), (a2), and (a3) ​​may be arranged regularly, like in a block copolymer, or randomly, like in a random copolymer. Preferably, the copolymer (A) is a random copolymer in which the repeating units (a1), (a2), and (a3) ​​are randomly arranged. 【0048】The copolymer (A) only needs to have the repeating unit (a1), the repeating unit (a2), and the repeating unit (a3), and may also have other repeating units. Examples of the other repeating units include repeating units derived from monovinyl aromatic compounds other than the repeating unit (a1), repeating units derived from aromatic ring-condensed cyclic olefin compounds other than the repeating unit (a3), repeating units derived from trivinyl aromatic compounds, repeating units derived from trivinyl aliphatic compounds, repeating units derived from divinyl aliphatic compounds, and repeating units derived from monovinyl aliphatic compounds. 【0049】 The aromatic ring-condensed cyclic olefin compound used to form a repeating unit derived from an aromatic ring-condensed cyclic olefin compound other than the repeating unit (a3) ​​is a cyclic olefin compound in which an aromatic ring is condensed, other than the acenaphthylene compound represented by the following formula (4). More specifically, the aromatic ring-condensed cyclic olefin compound is a compound other than the acenaphthylene compound represented by the following formula (4) that has a condensed ring of an aliphatic ring having a carbon-carbon double bond and an aromatic ring. The condensation may be ortho-condensation or ortho-peri-condensation. Examples of the aromatic ring-condensed cyclic olefin compound include indene compounds, phenalene compounds, acephenanthrylene compounds, aceanthrylene compounds, benzofuran compounds, and benzothiophene compounds. Among these, it is preferable that the aromatic ring-condensed cyclic olefin compound has three or fewer rings. Specific examples of aromatic ring-condensed cyclic olefin compounds with two rings include indene compounds, benzofuran compounds, and benzothiophene compounds. Furthermore, among the aromatic ring-condensed cyclic olefin compounds, those having three rings include, specifically, phenalene compounds. The aromatic ring-condensed cyclic olefin compounds may be used individually or in combination of two or more types. 【0050】Examples of the indene compound include at least one selected from the group consisting of indene, alkylindene, halogenated indene, arylindene, and alkoxyindene. Similarly, the phenalene compound, acephenanthrylene compound, aceanthrylene compound, benzofuran compound, and benzothiophene compound also include phenalene, acephenanthrylene, aceanthrylene, benzofuran, and benzothiophene, as well as compounds having substituents similar to those of the indene compound. 【0051】 In the copolymer (A), the content of the repeating units (a1) is not particularly limited, but for example, it is preferably 15 to 90 mol%, more preferably 30 to 80 mol%, even more preferably 40 to 75 mol%, and particularly preferably 50 to 70 mol%, relative to the total repeating units constituting the copolymer (A) (when the total repeating units constituting the copolymer (A) are 100 mol%). When the content of the repeating units (a1) in the copolymer (A) is 15 mol% or more, it exhibits an excellent effect in reducing melt viscosity. 【0052】 In the copolymer (A), the content of the repeating units (a2) is not particularly limited, but for example, it is preferably 3 to 30 mol%, more preferably 5 to 30 mol%, even more preferably 5 to 25 mol%, even more preferably 8 to 22 mol%, and particularly preferably 10 to 20 mol% relative to the total repeating units constituting the copolymer (A) (when the total repeating units constituting the copolymer (A) are 100 mol%). When the content of the repeating units (a2) in the copolymer (A) is 3 mol% or more, the thermosetting properties can be enhanced to obtain a good cured product, and the glass transition temperature can be increased. 【0053】In the copolymer (A), the content of the repeating units (a3) ​​is not particularly limited, but for example, it is preferably 5 to 80 mol%, more preferably 7 to 50 mol%, and even more preferably 8 to 35 mol%, relative to the total repeating units constituting the copolymer (A) (when the total repeating units constituting the copolymer (A) are 100 mol%). When the content of the repeating units (a3) ​​in the copolymer (A) is 80 mol% or less, it exhibits an excellent effect in improving the glass transition temperature. 【0054】 The total content of the repeating units (a1), (a2), and (a3) ​​is preferably 80 mol% or more, more preferably 90 mol% or more, and may be 100 mol%, relative to the total repeating units constituting the copolymer (A) (when the total repeating units constituting the copolymer (A) are 100 mol%). That is, the copolymer (A) may consist of the repeating units (a1), (a2), and (a3). 【0055】The copolymer (A) is preferably a copolymer having repeating units represented by formula (1) (preferably styrene units), repeating units represented by formula (3) (preferably divinylbenzene units), and repeating units represented by formula (2) (preferably acenaphthylene units). In such a copolymer, the content of repeating units represented by formula (1) (preferably styrene units) is preferably 15 to 90 mol%, more preferably 30 to 80 mol%, even more preferably 40 to 75 mol%, and particularly preferably 50 to 70 mol%, relative to the total repeating units constituting the copolymer (A) (when the total repeating units constituting the copolymer (A) are 100 mol%). Furthermore, the content of repeating units represented by formula (3) (preferably divinylbenzene units) is preferably 3 to 30 mol%, more preferably 5 to 30 mol%, even more preferably 5 to 25 mol%, even more preferably 8 to 22 mol%, and particularly preferably 10 to 20 mol%, relative to the total repeating units constituting the copolymer (A) (when the total repeating units constituting the copolymer (A) are 100 mol%). The content of repeating units represented by formula (2) (preferably acenaphthylene units) is preferably 5 to 80 mol%, more preferably 7 to 50 mol%, and even more preferably 8 to 35 mol%, relative to the total repeating units constituting the copolymer (A) (when the total repeating units constituting the copolymer (A) are 100 mol%). The copolymer (A) may have repeating units other than these repeating units in addition to these repeating units. 【0056】The copolymer (A) may have structures derived from the polymerization initiator at its ends. The content of each repeating unit does not include the structure derived from the polymerization initiator in all repeating units constituting the copolymer (A). That is, the content of each repeating unit is the content of all repeating units constituting the copolymer (A) other than the structure derived from the polymerization initiator (the content when all repeating units constituting the copolymer (A) other than the structure derived from the polymerization initiator are set to 100 mol%). 【0057】 As described above, the copolymer (A) may have a structure derived from a polymerization initiator at its end (the end of a linear copolymer). Specifically, the copolymer (A) may have a structure derived from a polymerization initiator represented by the following formula (5), or a structure derived from a polymerization initiator represented by the following formula (6). The polymerization initiator represented by the following formula (5) is an azo-based initiator that does not have a cyano group (nitrile group), unlike the general-purpose azo-based initiator azobisisobutyronitrile (AIBN). The polymerization initiator represented by the following formula (6) is an organic peroxide such as a dialkyl peroxide. Of these, by using the polymerization initiator represented by the following formula (5) as the polymerization initiator, better dielectric properties can be imparted. ５ -N = N - R ６ (5) Caution ７ -O-O-R ８ (6) 【0058】 In equations (5) and (6), R ５ , R ６ , R ７ , and R ８ Each of these independently represents a monovalent saturated hydrocarbon group or a monovalent aromatic hydrocarbon group and does not contain heteroatoms. The number of carbon atoms in the saturated hydrocarbon group is not particularly limited, but is preferably 1 to 23, and more preferably 4 to 13. The number of carbon atoms in the aromatic hydrocarbon group is not particularly limited, but is preferably 6 to 23, and more preferably 6 to 13. 【0059】The saturated hydrocarbon group may be a branched saturated aliphatic hydrocarbon group (alkyl group), a linear saturated aliphatic hydrocarbon group (alkyl group), or a saturated alicyclic hydrocarbon group. Examples of saturated aliphatic hydrocarbon groups include alkyl groups such as tert-butyl, tert-pentyl, tert-hexyl, and 1,1,3,3-tetramethylbutyl. Examples of saturated alicyclic hydrocarbon groups include cyclohexyl. Examples of aromatic hydrocarbon groups include aryl and aralkyl groups. Examples of aryl groups include phenyl, tolyl, and naphthyl. Examples of aralkyl groups include cumyl, benzyl, and phenethyl. 【0060】 R ５ , R ６ , R ７ , and R ８ Each of these may be an independent group represented by the following formula (7). 【0061】 【0062】 In formula (7), R ９ , R １０ , and R １１ Each of these independently represents a monovalent saturated hydrocarbon group or a monovalent aromatic hydrocarbon group. Among these, R ９ R represents a monovalent saturated hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms. １０ and R １１ It is preferable that it shows a methyl group, R ９ R represents a monovalent saturated hydrocarbon group having 1 to 10 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms. １０ and R １１It is more preferable that the group exhibits a methyl group. The saturated hydrocarbon group may be branched or linear. Examples of the saturated hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a heptyl group, an isopropyl group, a tert-butyl group, and a 2,2-dimethylpropyl group. The saturated hydrocarbon group may also be a saturated alicyclic hydrocarbon group such as a cyclohexyl group. Examples of the aromatic hydrocarbon group include a phenyl group, a tolyl group, a naphthyl group, and the like. 【0063】 When copolymer (A) is synthesized by radical polymerization using the polymerization initiator, copolymer (A) is obtained having structures derived from the polymerization initiator at both ends. Specifically, when the polymerization initiator represented by formula (5) is used as the polymerization initiator, R ５ A copolymer (A) having R at both ends ６ A copolymer (A) having - and R at one end ５ - has R at the other end. ６ Either copolymer (A) having - can be obtained. Also, when the polymerization initiator represented by formula (6) is used as the polymerization initiator, R is present at both ends. ７ A copolymer having -O-, with R at both ends ８ A copolymer (A) having -O-, and R at one end. ７ It has -O- and the other end has R ８ Either copolymer (A) having -O- is obtained. 【0064】 The weight-average molecular weight Mw of the copolymer (A) is not particularly limited and may be, for example, 1,000 to 100,000, 2,000 to 50,000, or 3,000 to 20,000. A weight-average molecular weight Mw of 1,000 or more can reduce the concentration of structures (end groups) derived from the polymerization initiator, thereby improving dielectric properties. Furthermore, a weight-average molecular weight Mw of 100,000 or less can reduce the melt viscosity. Here, the weight-average molecular weight Mw is the weight-average molecular weight on a polystyrene basis measured by gel permeation chromatography (GPC). 【0065】The method for producing the copolymer (A) is not particularly limited as long as it can produce the copolymer (A). Examples of methods for producing the copolymer (A) include copolymerizing a vinylbenzylphosphonium salt, the monovinyl aromatic compound (a monovinyl aromatic compound from which repeating units represented by formula (1) are obtained by polymerization), and the acenaphthylene compound using the polymerization initiator (for example, the polymerization initiator represented by formula (5) and the polymerization initiator represented by formula (6), etc.), and then reacting the resulting copolymer with formaldehyde. 【0066】 As the vinylbenzylphosphonium salt, it is preferable to use, for example, vinylbenzylphosphonium halide. Examples of phosphonium groups in the vinylbenzylphosphonium salt include quaternary phosphonium groups such as trialkylphosphonium, triarylphosphonium, and trialkylphosphonium. In addition, halogens that form a salt with the phosphonium group include not only chlorine but also bromine, for example. 【0067】The method for copolymerizing the vinylbenzylphosphonium salt with the monovinyl aromatic compound and the acenaphthylene compound is not particularly limited, and known vinyl polymerization methods can be used. By using at least one of the polymerization initiators represented by formula (5) and formula (6) as the polymerization initiator, a copolymer is obtained having repeating units derived from the vinylbenzylphosphonium salt, repeating units represented by formula (1), and repeating units represented by formula (2). In this copolymerization, a chain transfer agent may be added to adjust the molecular weight of the copolymer. Since the vinylbenzylphosphonium salt is monovinyl, this copolymerization method yields a linear copolymer that does not have branches. The method for reacting the obtained copolymer with formaldehyde is not particularly limited, and for example, a known Wittig reaction can be used. Specifically, the method may include treating the copolymer with a base and reacting it with formaldehyde. In this method, the phosphonium group is removed from the repeating units derived from the vinylbenzylphosphonium salt in the copolymer, and a vinyl group is introduced into the repeating units after the phosphonium group has been removed. As described above, the copolymerization method yields a linear copolymer without branching. By introducing vinyl groups into this linear copolymer, a linear copolymer (A) is obtained. That is, the copolymer obtained by the copolymerization method is a linear copolymer, and by introducing vinyl groups into the repeating units derived from the vinylbenzylphosphonium salt in this copolymer, it is possible to obtain copolymer (A) (a linear copolymer without branching) while having repeating units corresponding to a divinyl aromatic compound. 【0068】(Copolymer (B)) The copolymer (B) is not particularly limited as long as it is a copolymer (polyfunctional vinyl aromatic copolymer) that includes repeating units (b1) derived from a monovinyl aromatic compound and repeating units (b2) derived from a divinyl aromatic compound, and does not include repeating units represented by formula (2). Specifically, the copolymer (B) is a polyfunctional vinyl aromatic copolymer containing the repeating units (b1) and the repeating units (b2), wherein, with respect to the total of the repeating units (b1) and the repeating units (b2) (when the total of the repeating units (b1) and the repeating units (b2) is 100 mol%), the repeating units (b1) are included in 5 mol% or more and less than 98 mol%, and the repeating units (b2) are included in 2 mol% or more and less than 95 mol%, and as part of (b2), the following formula (8) Examples include soluble polyfunctional vinyl aromatic copolymers that contain repeating units (b2-1) having unsaturated groups represented by the formula (9), the mole fraction of the repeating unit (b2-1) in relation to the sum of the repeating units (b1) and (b2) satisfy the following formula (9), the number average molecular weight is 300 to 100,000, the molecular weight distribution expressed as the ratio of weight average molecular weight to number average molecular weight is 100.0 or less, and the copolymer is soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform. 【0069】 【0070】 In formula (8), R ２１ This represents an aromatic hydrocarbon group having 6 to 30 carbon atoms. 【0071】 0.02 ≤ (b2-1) / [(b1) + (b2)] ≤ 0.8 (9) The soluble polyfunctional vinyl aromatic copolymer contains the repeating unit (b1) and the repeating unit (b2) as described above, and further contains the repeating unit (b2-1) represented by formula (8) as part of the repeating unit (b2). In formula (8), R ２１ This represents an aromatic hydrocarbon group with 6 to 30 carbon atoms. 【0072】The soluble polyfunctional vinyl aromatic copolymer preferably contains 5 mol% or more and less than 98 mol% of the repeating unit (b1) and the repeating unit (b2) relative to the total of the repeating units (b1) and the repeating unit (b2) (when the total of the repeating units (b1) and the repeating unit (b2) is 100 mol%), and 2 mol% or more and less than 95 mol% of the repeating unit (b2). Furthermore, the soluble polyfunctional vinyl aromatic copolymer preferably contains 2 to 80 mol% of the repeating unit (b2-1) relative to the total of the repeating units (b1) and the repeating unit (b2) (when the total of the repeating units (b1) and the repeating unit (b2) is 100 mol%). 【0073】 The soluble polyfunctional vinyl aromatic copolymer preferably has a number average molecular weight Mn of 300 to 100,000, a molecular weight distribution expressed as the ratio of weight average molecular weight Mw to number average molecular weight Mn (Mw / Mn) of 100.0 or less, and is soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform. 【0074】 The soluble polyfunctional vinyl aromatic copolymer is not limited to, but examples include copolymers containing repeating units derived from the repeating unit (b1) represented by the following formula (10) and the repeating unit (b2) represented by the following formulas (11) and (12). These repeating units may be arranged regularly or randomly. 【0075】 【0076】 【0077】 【0078】 In the above formula (10), R ２２ R represents an aromatic hydrocarbon group having 6 to 30 carbon atoms derived from the monovinyl aromatic compound, and in formulas (11) and (12), ２１represents an aromatic hydrocarbon group having 6 to 30 carbon atoms derived from the divinyl aromatic compound, and in formulas (10) to (12), h to k each independently represent an integer from 0 to 200, provided that their sum is between 2 and 20,000. 【0079】 Suitable soluble polyfunctional vinyl aromatic copolymers include, for example, in formulas (10) to (12), R ２１ and R ２２ However, examples include copolymers consisting of repeating units which are aromatic hydrocarbon groups selected from the group consisting of optionally substituted phenyl groups, optionally substituted biphenyl groups, optionally substituted naphthalene groups, and optionally substituted terphenyl groups. 【0080】 The soluble polyfunctional vinyl aromatic copolymer is solvent-soluble. The repeating units are derived from monomers and include units that are present in the main chain of the copolymer and appear repeatedly, as well as units or terminal groups present in the terminals or side chains. The repeating units are also called structural units. In this specification, terminal groups include not only those derived from the monomers described above, but also terminal groups derived from the chain transfer agents described later. 【0081】The repeating unit (b2) is preferably contained in an amount of 2 mol% or more and less than 95 mol% relative to the total of the repeating units (b1) and (b2) (when the total of the repeating units (b1) and (b2) is 100 mol%). That is, the content of the repeating unit (b2) is preferably 2 mol% or more and less than 95 mol% relative to the total of the repeating units (b1) and (b2) (when the total of the repeating units (b1) and (b2) is 100 mol%). The repeating unit (b2) can have multiple structures, such as one vinyl group reacting or two vinyl groups reacting. Of these, the repeating unit in which only one vinyl group reacts, i.e., the repeating unit (b2-1) represented by formula (8), is preferably contained in an amount of 2 to 80 mol%, more preferably 5 to 70 mol%, even more preferably 10 to 60%, and particularly preferably 15 to 50% relative to the total. Including the repeating unit (b2-1) in an amount of 2 to 80 mol% relative to the total tends to result in a low dielectric loss tangent, high toughness, excellent heat resistance, and excellent compatibility with other resins. Furthermore, when used in a resin composition, it tends to exhibit excellent resistance to humid heat, resistance to heat-induced oxidative degradation, and moldability. When the repeating unit (b2-1) is less than 2 mol% relative to the total, heat resistance tends to decrease. Also, when the repeating unit (b2-1) is more than 80 mol% relative to the total, the interlayer peel strength when used in a laminate tends to decrease. 【0082】The soluble polyfunctional vinyl aromatic copolymer preferably contains the repeating unit (b1) in an amount of 5 mol% or more and less than 98 mol%, more preferably 10 mol% or more and less than 90 mol%, and even more preferably 15 mol% or more and less than 85 mol%, relative to the total. That is, the content of the repeating unit (b1) is preferably 5 mol% or more and less than 98 mol%, more preferably 10 mol% or more and less than 90 mol%, and even more preferably 15 mol% or more and less than 85 mol%, relative to the total of the repeating units (b1) and the repeating unit (b2) (when the total of the repeating units (b1) and the repeating unit (b2) is 100 mol%). If the amount of the repeating unit (b1) is less than 5 mol%, the moldability tends to be insufficient. Also, if the amount of the repeating unit (b1) exceeds 98 mol%, the heat resistance of the cured product tends to be insufficient. 【0083】 The vinyl groups present in the repeating unit (b2-1) act as crosslinking components and contribute to the heat resistance of the soluble polyfunctional vinyl aromatic copolymer. On the other hand, the repeating unit (b1) derived from the monovinyl aromatic compound is generally thought to undergo polymerization via a 1,2 addition reaction of vinyl groups and therefore does not contain vinyl groups. In other words, the repeating unit (b1) derived from the monovinyl aromatic compound does not act as a crosslinking component but contributes to the development of moldability. 【0084】Styrene is a preferred example of the monovinyl aromatic compound. In addition, monovinyl aromatic compounds other than styrene can be used as the monovinyl aromatic compound. In this case, the content of repeating units (b1-1) derived from styrene is preferably 99 to 20 mol%, and more preferably 98 to 30 mol%, relative to the total of repeating units (b1-1) derived from styrene and repeating units (b1-2) derived from monovinyl aromatic compounds other than styrene (when the total of repeating units (b1-1) and repeating units (b1-2) is 100 mol%). A content of repeating units (b1-1) within the above range is preferred because it tends to combine heat resistance to oxidative degradation and moldability. If the content of repeating units (b1-1) is greater than 99 mol% of the total, the heat resistance tends to decrease. Also, if the content of repeating units (b1-1) is greater than 80 mol% of the total [when the content of repeating units (b1-1) is less than 20 mol% of the total], the moldability tends to decrease. 【0085】 The number-average molecular weight Mn of the soluble polyfunctional vinyl aromatic copolymer (number-average molecular weight Mn in terms of standard polystyrene measured using GPC) is preferably 300 to 100,000, more preferably 400 to 50,000, and even more preferably 500 to 10,000. If the number-average molecular weight Mn of the soluble polyfunctional vinyl aromatic copolymer is less than 300, the amount of monofunctional copolymer components contained in the soluble polyfunctional vinyl aromatic copolymer increases, which tends to reduce the heat resistance of the cured product. Furthermore, if the number-average molecular weight Mn of the soluble polyfunctional vinyl aromatic copolymer exceeds 100,000, gel formation becomes easier, and the viscosity increases, which tends to reduce moldability. 【0086】The molecular weight distribution (Mw / Mn) of the soluble polyfunctional vinyl aromatic copolymer, expressed as the ratio of the weight-average molecular weight Mw (weight-average molecular weight Mw on a standard polystyrene basis measured using GPC) to the number-average molecular weight Mn, is 100.0 or less, preferably 50.0 or less, more preferably 1.5 to 30.0, and even more preferably 2.0 to 20.0. When Mw / Mn exceeds 100.0, the processing characteristics of the soluble polyfunctional vinyl aromatic copolymer tend to deteriorate, and gel formation tends to occur. 【0087】 The soluble polyfunctional vinyl aromatic copolymer is soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform as a solvent, and is preferably soluble in any of the above solvents. In order to be a solvent-soluble and polyfunctional copolymer, it is necessary that some of the vinyl groups of divinylbenzene remain uncrosslinked and have an appropriate degree of crosslinking. Here, "solubility in a solvent" means that 5 g or more of the soluble polyfunctional vinyl aromatic copolymer dissolves in 100 g of the solvent, preferably 30 g or more, and more preferably 50 g or more. 【0088】 The divinyl aromatic compound plays a role in forming a branched structure and making it polyfunctional, and also acts as a crosslinking component to exhibit heat resistance when the resulting soluble polyfunctional vinyl aromatic copolymer is thermoset. That is, the copolymer (B) has a branched structure because it has repeating units (b2) derived from the divinyl aromatic compound. Here, a branched structure is a structure having repeating units that become side chains branched from repeating units that become the main chain constituting the copolymer, and is distinguished from the linear structure. 【0089】The divinyl aromatic compound is not particularly limited as long as it is an aromatic compound having two vinyl groups, but for example, divinylbenzene (including each positional isomer or mixtures thereof), divinylnaphthalene (including each positional isomer or mixtures thereof), and divinylbiphenyl (including each positional isomer or mixtures thereof) are preferably used. These can be used individually or in combination of two or more. From the viewpoint of moldability, the divinyl aromatic compound is more preferably divinylbenzene (m-isomer, p-isomer, or mixture of positional isomers thereof). 【0090】 Examples of the monovinyl aromatic compounds include styrene and monovinyl aromatic compounds other than styrene. Styrene is essential as the monovinyl aromatic compound, and it is desirable to use other monovinyl aromatic compounds in combination. 【0091】 Styrene, as a monomer component, plays a role in imparting low dielectric properties and heat-resistant oxidative degradation to the soluble polyfunctional vinyl aromatic copolymer, and as a chain transfer agent, it plays a role in controlling the molecular weight of the soluble polyfunctional vinyl aromatic copolymer. 【0092】 The monovinyl aromatic compounds other than styrene improve the solvent solubility and processability of the soluble polyfunctional vinyl aromatic copolymer. 【0093】The monovinyl aromatic compounds other than styrene are not particularly limited as long as they are aromatic compounds other than styrene that have one vinyl group, but examples include vinyl aromatic compounds such as vinylnaphthalene and vinylbiphenyl; and nuclear alkyl-substituted vinyl aromatic compounds such as o-methylstyrene, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, o-ethylvinylbenzene, m-ethylvinylbenzene, and p-ethylvinylbenzene. The monovinyl aromatic compounds other than styrene are preferably ethylvinylbenzene (including each positional isomer or mixtures thereof), ethylvinylbiphenyl (including each positional isomer or mixtures thereof), or ethylvinylnaphthalene (including each positional isomer or mixtures thereof) because they prevent gelation of the soluble polyfunctional vinyl aromatic copolymer, have a high effect in improving solvent solubility and processability, are low in cost, and are readily available. From the viewpoint of dielectric properties and cost, the monovinyl aromatic compounds other than styrene are preferably ethylvinylbenzene (m-isomer, p-isomer, or mixtures of their positional isomers). 【0094】 Within the limits without impairing the effects of the present invention, in addition to the divinyl aromatic compound and the monovinyl aromatic compound, one or more other monomer components such as trivinyl aromatic compounds, trivinyl aliphatic compounds, divinyl aliphatic compounds, and monovinyl aliphatic compounds may be used, and repeating units (b3) derived therefrom may be introduced into the soluble polyfunctional vinyl aromatic copolymer. On the other hand, the copolymer (B) may contain repeating units (b3) derived from other monomer components, but it does not contain the repeating unit represented by formula (2). That is, the repeating unit (b3) does not contain the repeating unit represented by formula (2). 【0095】Examples of the other monomer components include 1,3,5-trivinylbenzene, 1,3,5-trivinylnaphthalene, 1,2,4-trivinylcyclohexane, ethylene glycol diacrylate, butadiene, 1,4-butanediol divinyl ether, cyclohexanedimethanol divinyl ether, diethylene glycol divinyl ether, and triallyl isocyanurate. These may be used individually or in combination of two or more. 【0096】 Preferably, the mole fraction of the other monomer components is less than 30 mol% of the total amount of all monomer components. In other words, it is preferable that the mole fraction of the repeating units (b3) derived from the other monomer components is less than 30 mol% of the total amount of repeating units [the repeating units (b1), the repeating units (b2), and the repeating units (b3)] derived from all monomer components constituting the soluble polyfunctional vinyl aromatic copolymer. 【0097】The soluble polyfunctional vinyl aromatic copolymer is obtained by polymerizing a monomer containing the divinyl aromatic compound and the monovinyl aromatic compound in the presence of a Lewis acid catalyst. The Lewis acid catalyst is not particularly limited as long as it is a compound consisting of a metal ion (acid) and a ligand (base) that can accept an electron pair, and from the viewpoint of the heat decomposition resistance of the resulting copolymer (B), for example, a metal fluoride or a complex thereof is preferred. Examples of the Lewis acid catalyst include divalent to hexavalent metal fluorides or complexes thereof such as B, Al, Ga, In, Si, Ge, Sn, Pb, Sb, Bi, Ti, W, Zn, Fe, and V. Among these, a boron trifluoride ether complex is preferred from the viewpoint of controlling the molecular weight and molecular weight distribution of the resulting copolymer (B) and polymerization activity. Here, examples of the ether in the ether complex include diethyl ether and dimethyl ether. These catalysts may be used individually or in combination of two or more types. Furthermore, known chain transfer agents (CTRs) can be added during polymerization to control the molecular weight. Since the chain transfer agent chemically modifies the ends of the copolymer (B), it also acts as a compound that introduces end groups that enable the conferring of functions such as toughness, low dielectric properties, and adhesion. Examples of compounds that function as such chain transfer agents include alcohol compounds, mercaptan compounds, carboxylic acid compounds, carboxylic acid anhydride compounds, ether compounds, thioether compounds, ester compounds, and thioester compounds. 【0098】 (Content) The content of copolymer (A) is preferably 10 to 90 parts by mass, and more preferably 20 to 80 parts by mass, based on 100 parts by mass of the total of copolymer (A) and copolymer (B). That is, the content ratio of copolymer (A) to copolymer (B) is preferably 10:90 to 90:10 by mass, and more preferably 20:80 to 80:20. 【0099】 The content of the copolymer (A) is preferably 4 to 96 parts by mass, and more preferably 10 to 50 parts by mass, per 100 parts by mass of the resin composition. 【0100】 The content of the copolymer (B) is preferably 4 to 96 parts by mass, and more preferably 10 to 50 parts by mass, per 100 parts by mass of the resin composition. 【0101】 The total content of copolymer (A) and copolymer (B) is preferably 20 parts by mass or more, more preferably 40 parts by mass or more, and may be 100 parts by mass, per 100 parts by mass of the resin composition. 【0102】 If the amount of copolymer (A) is too small, the effects that are achieved by including copolymer (A) tend to be less pronounced. Conversely, if the amount of copolymer (A) is too large, the amount of copolymer (B) decreases, and the effects that are achieved by including copolymer (B) tend to be less pronounced. Therefore, if the amount of copolymer (A) is too small or too large, it tends to be difficult to obtain a cured product with low dielectric properties even after heating, and with suppressed fluctuations in dielectric properties and mass due to temperature changes. If the content of copolymer (A) and copolymer (B) is within the above range, a cured product with low dielectric properties even after heating, and with suppressed fluctuations in dielectric properties and mass due to temperature changes can be suitably obtained. 【0103】 (Other Components) The resin composition may optionally contain components other than copolymer (A) and copolymer (B), as long as they do not impair the effects of the present invention. Other components contained in the resin composition according to this embodiment may further include, for example, a curing agent, an inorganic filler, a reaction initiator, a reaction accelerator, a catalyst, a polymerization retarder, a polymerization inhibitor, a dispersant, a leveling agent, a coupling agent, an antifoaming agent, an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a dye or pigment, and an additive such as a lubricant. 【0104】As described above, the resin composition according to this embodiment may contain a curing agent. Examples of the curing agent include a curing agent that reacts with at least one of copolymer (A) and copolymer (B) to contribute to the curing of the resin composition. Specific examples of the curing agent include allyl compounds, methacrylate compounds, acrylate compounds, acenaphthylene compounds, vinyl compounds, maleimide compounds, polyphenylene ether compounds, cyanate ester compounds, activated ester compounds, and benzoxazine compounds. 【0105】 The allyl compounds are compounds having an allyl group in their molecule, and examples include triallyl isocyanurate compounds such as triallyl isocyanurate (TAIC), diallyl bisphenol compounds, and diallyl phthalate (DAP). 【0106】 The methacrylate compound is a compound having a methacryloyl group in its molecule, and examples include monofunctional methacrylate compounds having one methacryloyl group in their molecule, and polyfunctional methacrylate compounds having two or more methacryloyl groups in their molecule. Examples of the monofunctional methacrylate compound include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Examples of the polyfunctional methacrylate compound include dimethacrylate compounds such as tricyclodecanedimethanol dimethacrylate (DCP). 【0107】 The acrylate compound is a compound having an acryloyl group in its molecule, and examples include monofunctional acrylate compounds having one acryloyl group in their molecule, and polyfunctional acrylate compounds having two or more acryloyl groups in their molecule. Examples of the monofunctional acrylate compound include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. Examples of the polyfunctional acrylate compound include diacrylate compounds such as tricyclodecanedimethanol diacrylate. 【0108】The aforementioned acenaphthylene compound is a compound having an acenaphthylene structure in its molecule. Examples of the aforementioned acenaphthylene compound include acenaphthylene, alkylacenaphthylenes, halogenated acenaphthylenes, and phenylacenaphthylenes. Examples of the aforementioned 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. 【0109】 The vinyl compound is a compound having a vinyl group in its molecule. Examples of the vinyl compound include monofunctional vinyl compounds (monovinyl compounds) having one vinyl group in their molecule, and polyfunctional vinyl compounds having two or more vinyl groups in their molecule. Examples of the polyfunctional vinyl compound include polyfunctional aromatic vinyl compounds and vinyl hydrocarbon compounds. Examples of the vinyl hydrocarbon compounds include divinylbenzene and polybutadiene compounds. 【0110】The maleimide compound is a compound having a maleimide group in its molecule. Examples of the maleimide compound include a monofunctional maleimide compound having one maleimide group in its molecule, a polyfunctional maleimide compound having two or more maleimide groups in its molecule, and a modified maleimide compound. Examples of the modified maleimide compound include a modified maleimide compound in which part of the molecule is modified with an amine compound, a modified maleimide compound in which part of the molecule is modified with a silicone compound, and a modified maleimide compound in which part of the molecule is modified with both an amine compound and a silicone compound. 【0111】 The polyphenylene ether compound is a compound having a polyphenylene ether chain in its molecule. Examples of the polyphenylene ether compound include a polyphenylene ether compound having an unsaturated double bond in its molecule. More specifically, examples of the polyphenylene ether compound include a polyphenylene ether compound having a vinyl benzyl group (ethenyl benzyl group) in its molecule (vinyl benzyl-modified polyphenylene ether), a polyphenylene ether compound having an acryloyl group in its molecule (acrylic-modified polyphenylene ether), and a polyphenylene ether compound having a methacryloyl group in its molecule (methacrylic-modified polyphenylene ether). 【0112】 The cyanate ester compound is a compound having a cyanate group in its molecule, and examples include 2,2-bis(4-cyanatephenyl)propane, bis(3,5-dimethyl-4-cyanatephenyl)methane, and 2,2-bis(4-cyanatephenyl)ethane. 【0113】The aforementioned active ester compounds are compounds having highly reactive ester groups in their molecules, and examples include benzenecarboxylic acid active esters, benzenedicarboxylic acid active esters, benzenetricarboxylic acid active esters, benzenetetracarboxylic acid active esters, naphthalenecarboxylic acid active esters, naphthalenedicarboxylic acid active esters, naphthalentricarboxylic acid active esters, naphthalenetetracarboxylic acid active esters, fluorenecarboxylic acid active esters, fluorentricarboxylic acid active esters, and fluorenetetracarboxylic acid active esters. 【0114】 The aforementioned benzoxazine compound is a compound having a benzoxazine ring within its molecule, and examples include benzoxazine resins. 【0115】 The curing agent may be used alone or in combination of two or more types. 【0116】As described above, the resin composition according to this embodiment may contain an inorganic filler. The inorganic filler is not particularly limited as long as it is an inorganic filler that can be used as an inorganic filler contained in the resin composition. Examples of the inorganic filler include metal oxide fillers, metal hydroxide fillers, molybdate fillers, nitride fillers, titanate fillers, magnesium carbonate fillers such as anhydrous magnesium carbonate fillers, calcium carbonate fillers, quartz glass fillers, talc fillers, aluminum borate fillers, and barium sulfate fillers. Examples of the metal oxide fillers include silica fillers, alumina fillers, titanium oxide fillers, magnesium oxide fillers, and mica fillers. Examples of the silica fillers include crushed silica, spherical silica such as molten spherical silica, and silica particles. Examples of the metal hydroxide fillers include magnesium hydroxide fillers and aluminum hydroxide fillers. Examples of the molybdate fillers include zinc molybdate fillers, calcium molybdate fillers, and magnesium molybdate fillers. Examples of the nitride fillers include aluminum nitride fillers and boron nitride fillers. Examples of the titanate fillers include barium titanate fillers, strontium titanate fillers, calcium titanate fillers, and aluminum titanate fillers. Among these, silica fillers, metal hydroxide fillers such as magnesium hydroxide fillers and aluminum hydroxide fillers, aluminum oxide fillers, boron nitride fillers, strontium titanate fillers, calcium titanate fillers, and zinc molybdate fillers are preferred, with silica fillers being more preferred. The silica fillers are not particularly limited, but for example, they may be solid silica particles or hollow silica particles. Furthermore, the inorganic fillers may be used alone or in combination of two or more types.When using two or more of the aforementioned inorganic fillers in combination, silica filler may be used in combination with one or more other inorganic fillers, and it is preferable to use silica filler in combination with zinc molybdate filler. Furthermore, the inorganic filler may be, for example, talc filler supporting molybthenate in the molybdate filler. 【0117】 The inorganic filler may be a surface-treated inorganic filler or an untreated inorganic filler. Examples of surface treatments include treatment with a silane coupling agent. 【0118】 The silane coupling agent is not particularly limited, and examples include silane coupling agents having at least one functional group selected from the group consisting of vinyl group, styryl group, methacryloyl group, acryloyl group, phenylamino group, isocyanurate group, ureido group, mercapto group, isocyanate group, epoxy group, and acid anhydride group. That is, this silane coupling agent has at least one of vinyl group, styryl group, methacryloyl group, acryloyl group, phenylamino group, isocyanurate group, ureido group, mercapto group, isocyanate group, epoxy group, and acid anhydride group as a reactive functional group, and further includes compounds having hydrolyzable groups such as methoxy group and ethoxy group. 【0119】Examples of silane coupling agents that have a vinyl group include vinyltriethoxysilane and vinyltrimethoxysilane. Examples of silane coupling agents that have a styryl group include p-styryltrimethoxysilane and p-styryltriethoxysilane. Examples of silane coupling agents that have a methacryloyl group include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropylethyldiethoxysilane. Examples of silane coupling agents that have an acryloyl group include 3-acryloxypropyltrimethoxysilane and 3-acryloxypropyltriethoxysilane. Examples of silane coupling agents having a phenylamino group include N-phenyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltriethoxysilane. 【0120】 The average particle diameter of the inorganic filler is not particularly limited, but is preferably 0.05 to 10 μm, and more preferably 0.1 to 8 μm. Here, the average particle diameter refers to the volume-average particle diameter. The volume-average particle diameter can be measured, for example, by laser diffraction. 【0121】As described above, the resin composition according to this embodiment may contain a reaction initiator. Even if the resin composition does not contain a reaction initiator, the curing reaction can proceed. However, depending on the process conditions, it may be difficult to raise the temperature until curing proceeds, so a reaction initiator may be added. The reaction initiator is not particularly limited as long as it can promote the curing reaction of the resin composition, and examples include peroxides and organic azo compounds. Examples of peroxides include dicumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexine, and benzoyl peroxide. Examples of organic azo compounds include azobisisobutyronitrile. In addition, metal carboxylate salts can be used in combination as needed. By doing so, the curing reaction can be further promoted. Among these, α,α'-bis(t-butylperoxy-m-isopropyl)benzene is preferably used. α,α'-bis(t-butylperoxy-m-isopropyl)benzene has a relatively high reaction initiation temperature, which can suppress the acceleration of the curing reaction at times when curing is not required, such as during prepreg drying, thereby suppressing the deterioration of the shelf life of the resin composition. Furthermore, because α,α'-bis(t-butylperoxy-m-isopropyl)benzene has low volatility, it does not volatilize during prepreg drying or storage, resulting in good stability. The reaction initiator may be used alone or in combination of two or more types. 【0122】 As described above, the resin composition according to this embodiment may contain a coupling agent. The coupling agent may be contained in the resin composition, or it may be contained in the inorganic filler as a coupling agent pre-surface-treated. In the case of a prepreg, the prepreg may contain a coupling agent pre-surface-treated on the fibrous substrate. Examples of the coupling agent include those similar to the coupling agent used when surface-treating the inorganic filler as described above. 【0123】As described above, the resin composition according to this embodiment may contain a flame retardant. By including a flame retardant, the flame retardancy of the cured resin composition can be enhanced. The flame retardant is not particularly limited. Specifically, in fields where halogen-based flame retardants such as brominated flame retardants are used, for example, ethylenedipentabromobenzene, ethylenebistetrabromoimide, decabromodiphenyl oxide, tetradecabromodiphenoxybenzene, and bromostyrene compounds that react with the polymerizable compound are preferred, each having a melting point of 300°C or higher. It is believed that by using a halogen-based flame retardant, the desorption of halogens at high temperatures can be suppressed, thereby suppressing a decrease in heat resistance. In addition, in fields where halogen-free is required, a phosphorus-containing flame retardant (phosphorus-based flame retardant) may be used. The phosphorus-based flame retardant is not particularly limited, but 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. Specific examples of bis-diphenylphosphine oxide-based flame retardants include xylylene bis-diphenylphosphine oxide. Specific examples of phosphinate-based flame retardants include, for example, phosphinate metal salts of aluminum dialkylphosphinate. The flame retardants described above may be used individually or in combination of two or more. 【0124】 As described above, the resin composition according to this embodiment may contain a thermoplastic resin. Examples of the thermoplastic resin include styrene copolymers. 【0125】The styrene polymer is not particularly limited as long as it is a styrene polymer that can be used as a resin in a resin composition used to form an insulating layer in metal-clad laminates and wiring boards, etc. The resin composition used to form an insulating layer in metal-clad laminates and wiring boards, etc. may be a resin composition used to form a resin layer in resin-coated films and resin-coated metal foils, etc., or a resin composition contained in a prepreg. 【0126】 Examples of the styrene-based polymer include styrene-based polymers that are solid at 25°C. It is believed that including a styrene-based polymer that is solid at 25°C can provide even lower dielectric properties (low dielectric loss tangent) and a lower coefficient of thermal expansion in the cured product. The styrene-based polymer may also be a polymer obtained by polymerizing monomers containing styrene-based monomers, or a styrene-based copolymer. Examples of the styrene-based copolymer include a copolymer obtained by copolymerizing one or more of the styrene-based monomers with one or more other monomers copolymerizable with the styrene-based monomers. The styrene-based copolymer may be a random copolymer or a block copolymer, as long as it has a structure derived from the styrene-based monomers in its molecule. Examples of the block copolymer include a binary copolymer of a structure (repeating unit) derived from the styrene monomer and another copolymerizable monomer (repeating unit), a ternary copolymer of a structure (repeating unit) derived from the styrene monomer and another copolymerizable monomer (repeating unit) and a structure (repeating unit) derived from the styrene monomer, and a ternary copolymer of a random copolymer block (repeating unit) containing a structure (repeating unit) derived from the styrene monomer and the other copolymerizable monomer and the styrene monomer, and a structure (repeating unit) derived from the styrene monomer. The styrene polymer may also be a hydrogenated styrene copolymer obtained by hydrogenating the styrene copolymer. Furthermore, the styrene polymer may be the styrene copolymer, the styrene copolymer in which at least a portion is hydrogenated, or a part of the hydrogenated styrene copolymer modified with maleic anhydride. 【0127】 The styrene monomer is not particularly limited, but examples include styrene, styrene derivatives, styrene in which some of the hydrogen atoms of the benzene ring are substituted with alkyl groups, styrene in which some of the hydrogen atoms of the vinyl group are substituted with alkyl groups, vinyltoluene, α-methylstyrene, butylstyrene, dimethylstyrene, and isopropenyltoluene. The styrene monomer may be used individually or in combination of two or more. 【0128】 The styrene-based polymer preferably has ethylene structural units and butylene structural units in its molecule. 【0129】 The ethylene structural unit is not particularly limited, but examples include structural units (repeating units) derived from other copolymerizable monomers that have an ethylene structure. The ethylene structural unit is a structure derived from a 1,4-bond of a conjugated diene monomer (conjugated dienes), and the atom or group bonded to the carbon of the -C-C-bond in the main chain is a hydrogen atom or a methyl group. Specific examples of the conjugated diene monomer include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-cyclohexadiene. Therefore, the ethylene structural units specifically include structural units having an ethylene structure among the structural units derived from the conjugated dienes, and more specifically, structural units having an ethylene structure (1,4-addition structural units) among the structural units (repeating units) derived from 1,3-butadiene. 【0130】The butylene structural unit is not particularly limited, but examples include structural units (repeating units) derived from other copolymerizable monomers that have a butylene structure. The butylene structural unit is at least one of a structure derived from a 1,2-bond of a conjugated diene monomer (conjugated dienes) and a structure derived from a 3,4-bond of a conjugated diene monomer (conjugated dienes), and at least one of the atoms or groups bonded to the carbon of the -C-C-bond of the main chain is a side chain having two or more carbon atoms. Therefore, the butylene structural unit specifically includes structural units derived from the conjugated dienes that have a butylene structure, and more specifically, structural units (repeating units) derived from 1,3-butadiene that have a butylene structure (at least one of a 1,2-addition structural unit and a 3,4-addition structural unit). The butylene structural unit may be, for example, a hydrogenated structural unit. In the aforementioned styrene-based polymer, it is believed that a lower coefficient of thermal expansion is possible as the proportion of butylene structural units increases. 【0131】 The styrene-based polymer may contain structural units (repeating units) derived from other copolymerizable monomers other than the ethylene structural unit and the butylene structural unit. Such other copolymerizable monomers are not particularly limited, but examples include olefins such as α-pinene, β-pinene, and dipentene, and non-conjugated dienes such as 1,4-hexadiene and 3-methyl-1,4-hexadiene. These other copolymerizable monomers may be used individually or in combination of two or more. 【0132】More specifically, the styrene-based polymers include methylstyrene (ethylene / butylene) methylstyrene block copolymer, methylstyrene (ethylene-ethylene / propylene) methylstyrene block copolymer, styrene isoprene block copolymer, styrene isoprene styrene block copolymer, styrene (ethylene / butylene) styrene block copolymer, styrene (ethylene-ethylene / propylene) styrene block copolymer, methylstyrene (styrene / butadiene random copolymer block) methylstyrene copolymer, styrene (styrene / butadiene random copolymer block) styrene copolymer, styrene butadiene styrene block copolymer, and other styrene butadiene block copolymers, as well as styrene (butadiene / butylene) styrene copolymers. Furthermore, the styrene-based polymer may be a styrene-based polymer in which at least a portion of the styrene-based copolymer has been hydrogenated. In addition, the styrene-based polymer may be a styrene-based polymer in which at least a portion of the styrene-based polymer has been acid-modified, or a styrene-based polymer in which at least a portion of the styrene-based polymer has been acid-modified with maleic anhydride. 【0133】 The styrene-based polymer preferably has a weight-average molecular weight of 10,000 to 300,000, and more preferably 10,000 to 200,000. The weight-average molecular weight can be measured by any general molecular weight measurement method, specifically, values ​​measured using gel permeation chromatography (GPC). 【0134】 The styrene-based polymer may be one of the exemplified styrene-based polymers used alone, or two or more may be used in combination. 【0135】When the resin composition according to this embodiment contains the styrene polymer, its content is preferably 5 to 50 parts by mass, and more preferably 5 to 45 parts by mass, based on 100 parts by mass of the resin components in the resin composition. Furthermore, when the resin composition according to this embodiment contains only the copolymer (A), the copolymer (B), and the styrene polymer as its resin components, its content is preferably 5 to 50 parts by mass, and more preferably 5 to 45 parts by mass, based on 100 parts by mass of the total of these components. 【0136】 The resin composition according to this embodiment yields a cured product with low dielectric properties even after heating, and in which fluctuations in dielectric properties and mass due to temperature changes are suppressed. Specifically, the cured product obtained by curing the resin composition can sufficiently suppress the increase in dielectric properties such as dielectric loss tangent due to deterioration by oxidation, for example, even when heated. Furthermore, even when heated, the cured product can sufficiently suppress the decrease in mass due to thermal decomposition, etc. 【0137】 (Applications) The resin composition is used in the manufacture of prepregs, as described later. The resin composition is also used in the formation of resin layers in resin-coated metal foils and resin-coated films, and insulating layers in metal-clad laminates and wiring boards. 【0138】 (Manufacturing Method) The method for manufacturing the resin composition is not particularly limited, and examples include mixing copolymer (A), copolymer (B), and, if necessary, other components in predetermined amounts. In addition, when obtaining a varnish-like composition containing an organic solvent, the method described later may be used. 【0139】 [Prepreg, metal-clad laminate, wiring board, resin-coated metal foil, and resin-coated film] By using the resin composition according to this embodiment, prepreg, metal-clad laminate, wiring board, resin-coated metal foil, and resin-coated film can be obtained as follows. 【0140】 (Prepreg) Figure 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention. 【0141】As shown in Figure 1, the prepreg 1 according to this embodiment comprises the resin composition or a semi-cured product 2 of the resin composition and a fibrous base material 3. This prepreg 1 comprises the resin composition or a semi-cured product 2 of the resin composition and a fibrous base material 3 present in the resin composition or the semi-cured product 2 of the resin composition. 【0142】 In this embodiment, a semi-cured product refers to a resin composition that has been partially cured to the extent that it can be further cured. In other words, a semi-cured product is a resin composition that has been partially cured (stage B). For example, when a resin composition is heated, its viscosity gradually decreases at first, and then curing begins, causing the viscosity to gradually increase. In such a case, a semi-cured state would be the state between the time the viscosity begins to increase and before it is completely cured. 【0143】 The prepreg obtained using the resin composition according to this embodiment may include a semi-cured product of the resin composition as described above, or it may include 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 stage B) and a fibrous substrate, or it may be a prepreg comprising the uncured resin composition (the resin composition in stage A) and a fibrous substrate. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried. 【0144】 When manufacturing the prepreg, the resin composition 2 is often prepared in a varnish-like form for impregnation into the fibrous substrate 3, which is the base material for forming the prepreg. That is, the resin composition 2 is usually a resin varnish prepared in a varnish-like form. Such a varnish-like resin composition (resin varnish) is prepared, for example, as follows. 【0145】First, each component that can be dissolved in an organic solvent is added to the organic solvent and dissolved. Heating may be used as needed during this process. Then, components that cannot be dissolved in the organic solvent are added as needed, and the mixture is dispersed using a ball mill, bead mill, planetary mixer, roll mill, etc., until a predetermined dispersion state is reached, thereby preparing a varnish-like resin composition. The organic solvent used here is not particularly limited as long as it dissolves copolymer (A) and copolymer (B), etc., and does not inhibit the curing reaction. Specifically, examples include toluene and methyl ethyl ketone (MEK). 【0146】 Specific examples of the fibrous substrate include glass cloth, aramid cloth, polyester cloth, liquid crystal polymer (LCP) cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. When glass cloth is used, a laminate with excellent mechanical strength can be obtained, and flattened glass cloth is particularly preferred. Specific examples of the flattening process include a method in which the glass cloth is continuously pressed with a press roll at an appropriate pressure to flatten the yarn. The thickness of the fibrous substrate is generally 0.01 mm to 0.3 mm. The glass fibers constituting the glass cloth are not particularly limited, but examples include Q glass, NE glass, NER glass, NEZ glass, E glass, S glass, T glass, L glass, and L2 glass. The surface of the fibrous substrate may also be surface-treated with a silane coupling agent. The silane coupling agent is not particularly limited, but examples include a silane coupling agent having at least one group selected from the group consisting of vinyl, acryloyl, methacryloyl, styryl, amino, and epoxy groups in its molecule. 【0147】 The method for manufacturing the prepreg is not particularly limited as long as it allows for the production of the prepreg. Specifically, when manufacturing the prepreg, the resin composition according to this embodiment is often prepared in a varnish-like state and used as a resin varnish, as described above. 【0148】 A specific method for manufacturing the prepreg 1 is to impregnate a fibrous substrate 3 with the resin composition 2, for example, a resin composition 2 prepared in the form of a varnish, and then dry it. The resin composition 2 is impregnated into the fibrous substrate 3 by immersion, coating, etc. It is also possible to repeat the impregnation process multiple times as needed. Furthermore, by repeating the impregnation process using multiple resin compositions with different compositions and concentrations, it is possible to adjust the final composition and amount of impregnation to the desired level. 【0149】 The fibrous substrate 3 impregnated with the resin composition (resin varnish) 2 is heated under desired heating conditions, for example, at 40°C to 180°C for 1 minute to 10 minutes. Heating yields a prepreg 1 in either a pre-cured state (Stage A) or a semi-cured state (Stage B). Heating can also cause organic solvents to volatilize from the resin varnish, reducing or removing them. 【0150】 (Metal-clad laminate) Figure 2 is a schematic cross-sectional view showing an example of a metal-clad laminate 11 according to an embodiment of the present invention. 【0151】 As shown in Figure 2, the metal-clad laminate 11 according to this embodiment has an insulating layer 12 containing a cured product of the resin composition and a metal foil 13 provided on the insulating layer 12. Examples of the metal-clad laminate 11 include a metal-clad laminate composed of an insulating layer 12 containing a cured product of the prepreg 1 shown in Figure 1 and a metal foil 13 laminated together with 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 is not particularly limited and varies depending on the performance required of the final printed circuit board. The thickness of the metal foil 13 can be set appropriately according to 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, and if the metal foil is thin, it may be a carrier-equipped copper foil with a release layer and carrier to improve handling. 【0152】The method for manufacturing the metal-clad laminate 11 is not particularly limited as long as it can be manufactured. Specifically, one method is to manufacture the metal-clad laminate 11 using the prepreg 1. This method involves stacking one or more prepreg 1 sheets, further stacking metal foil 13 such as copper foil on both the top and bottom surfaces or one or both surfaces, and then heat-pressure-molding the metal foil 13 and the prepreg 1 to laminate and integrate them, thereby producing a laminate 11 with metal foil on both sides or one side. In other words, the metal-clad laminate 11 is obtained by laminating the metal foil 13 onto the prepreg 1 and then heat-pressure-molding it. The heating and pressing conditions can be appropriately set depending on the thickness of the metal-clad laminate 11 and the type of resin composition contained in the prepreg 1. For example, the temperature can be 170 to 230°C, the pressure 0.5 to 5 MPa, and the time 60 to 150 minutes. The metal-clad laminate may also be manufactured without using prepreg. For example, one method involves applying a varnish-like resin composition onto a metal foil to form a layer containing the resin composition on the metal foil, and then heating and pressurizing it. 【0153】 (Wiring board) Figure 3 is a schematic cross-sectional view showing an example of a wiring board 21 according to an embodiment of the present invention. 【0154】 As shown in Figure 3, the wiring board 21 according to this embodiment has an insulating layer 12 containing a cured product of the resin composition and wiring 14 provided on the insulating layer 12. Examples of the wiring board 21 include a wiring board composed of an insulating layer 12 made by curing the prepreg 1 shown in Figure 1, and wiring 14 laminated together with the insulating layer 12 and formed by partially removing the metal foil 13. Furthermore, the insulating layer 12 may be made of a cured product of the resin composition, or it 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 be manufactured. Specifically, a method for manufacturing the wiring board 21 using the prepreg 1 can be mentioned. For example, this method involves etching the metal foil 13 on the surface of the metal-clad laminate 11 manufactured as described above to form wiring, thereby manufacturing a wiring board 21 in which wiring is provided as a circuit on the surface of the insulating layer 12. That is, the wiring board 21 is obtained by partially removing the metal foil 13 on the surface of the metal-clad laminate 11 to form a circuit. In addition to the above method, other methods for forming circuits include, for example, circuit formation by the semi-additive process (SAP) or the modified semi-additive process (MSAP). 【0156】 (Metal foil with resin) Figure 4 is a schematic cross-sectional view showing an example of a metal foil with resin 31 according to this embodiment. 【0157】 As shown in Figure 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. This resin-coated metal foil 31 has the metal foil 13 on the surface of the resin layer 32. That is, this resin-coated metal foil 31 comprises the resin layer 32 and the metal foil 13 laminated together with the resin layer 32. In addition, the resin-coated metal foil 31 may have other layers between the resin layer 32 and the metal foil 13. 【0158】The resin layer 32 may contain a semi-cured product of the resin composition as described above, or it 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 stage B) and a metal foil, or it may comprise a resin layer containing the uncured resin composition (the resin composition in stage A) and a metal foil. Furthermore, 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. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried. Furthermore, the fibrous substrate may be the same as the fibrous substrate of a prepreg. 【0159】 The aforementioned metal foil can be any metal foil used in metal-clad laminates or resin-coated metal foils without limitation. Examples of such metal foils include copper foil and aluminum foil. 【0160】 The resin-coated metal foil 31 may be provided with a cover film or the like, if necessary. Providing a cover film can prevent the incorporation of foreign matter. The cover film is not particularly limited, but examples include polyolefin film, polyester film, polymethylpentene film, and films formed by providing a release agent layer on these films. 【0161】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 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, by using a bar coater. The applied resin composition is heated, for example, at a temperature of 40°C to 180°C for 0.1 minutes to 10 minutes. The heated resin composition is formed on the metal foil 13 as an uncured resin layer 32. The heating can cause the organic solvent to volatilize from the resin varnish, thereby reducing or removing the organic solvent. 【0162】 (Resin-coated film) Figure 5 is a schematic cross-sectional view showing an example of a resin-coated film 41 according to this embodiment. 【0163】 As shown in Figure 5, the resin-coated film 41 according to this embodiment comprises a resin layer 42 containing the resin composition or a semi-cured product of the resin composition, and a support film 43. This resin-coated film 41 comprises the resin layer 42 and a support film 43 laminated together with the resin layer 42. The resin-coated film 41 may also have other layers between the resin layer 42 and the support film 43. 【0164】The resin layer 42 may contain a semi-cured product of the resin composition as described above, or it may contain the uncured resin composition. That is, the resin-coated film 41 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition of stage B) and a support film, or it may comprise a resin layer containing the uncured resin composition (the resin composition of stage A) and a support film. Furthermore, 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. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried. Furthermore, the fibrous substrate may be the same as the fibrous substrate of the prepreg. 【0165】 The support film 43 can be any support film used for resin-coated films without limitation. Examples of such support films include polyester film, polyethylene terephthalate (PET) film, polyimide film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, polyamide film, polycarbonate film, and electrically insulating films such as polyarylate film. 【0166】 The resin-coated film 41 may be provided with a cover film or the like, if necessary. Providing a cover film can prevent the incorporation of foreign matter. The cover film is not particularly limited, but examples include polyolefin film, polyester film, and polymethylpentene film. 【0167】 The support film and the cover film may be subjected to surface treatments such as matte treatment, corona treatment, release treatment, and roughening treatment, as needed. 【0168】The method for manufacturing the resin-coated film 41 is not particularly limited as long as it can be manufactured. Examples of methods for manufacturing the resin-coated film 41 include applying the varnish-like resin composition (resin varnish) onto a support film 43 and heating it. The varnish-like resin composition is applied onto the support film 43, for example, by using a bar coater. The applied resin composition is heated, for example, at a temperature of 40°C to 180°C for 0.1 minutes to 10 minutes. The heated resin composition is formed on the support film 43 as an uncured resin layer 42. The heating can cause organic solvents to volatilize from the resin varnish, thereby reducing or removing the organic solvents. 【0169】 The resin composition according to this embodiment, when cured, becomes a cured product with low dielectric properties even after heating, and in which fluctuations in dielectric properties and mass due to temperature changes are suppressed. For this reason, when the prepreg is cured, it becomes a cured product with low dielectric properties even after heating, and in which fluctuations in dielectric properties and mass due to temperature changes are suppressed. The resin-coated metal foil and the resin-coated film are, respectively, resin-coated metal foil and the resin-coated film, which comprise a resin layer that, when cured, becomes an insulating layer containing the cured product. The metal-clad laminate and the wiring board are, respectively, metal-clad laminate and wiring board, which comprise an insulating layer containing the cured product. The prepreg, the resin-coated film, the resin-coated metal foil, and the metal-clad laminate can be suitably used in the manufacture of the wiring board, and can also be used, for example, in the manufacture of a multilayer wiring board. For example, in the case of the resin-coated film, a multilayer wiring board can be manufactured by laminating it on the wiring board and then peeling off the support film, or by laminating it on the wiring board after peeling off the support film. If the resin-coated metal foil is used, for example, a multilayer wiring board can be manufactured by laminating it on a wiring board. In this way, by using the resin-coated film and the resin-coated metal foil, a multilayer wiring board having an insulating layer containing the cured material can be manufactured. 【0170】As described above, this specification discloses various aspects of technology, the main technologies being summarized below. 【0171】 A resin composition according to a first aspect of the present invention is a resin composition containing a linear copolymer (A) comprising a repeating unit (a1) represented by formula (1), a repeating unit (a2) derived from a divinyl aromatic compound, and a repeating unit (a3) ​​represented by formula (2), and a copolymer (B) comprising a repeating unit (b1) derived from a monovinyl aromatic compound and a repeating unit (b2) derived from a divinyl aromatic compound, but without the repeating unit represented by formula (2). 【0172】 A resin composition according to a second aspect of the present invention is a resin composition according to a first aspect of the present invention in which the copolymer (B) has a branched structure. 【0173】 A third aspect of the present invention is a resin composition in which, in the first or second aspect of the present invention, the content ratio of copolymer (A) to copolymer (B) is 10:90 to 90:10 by mass. 【0174】 A fourth aspect of the present invention is a resin composition according to any one of the first to third aspects of the present invention, wherein the content of the repeating unit (a1) is 15 to 90 mol% with respect to the total repeating units constituting the copolymer (A). 【0175】 A fifth aspect of the present invention is a resin composition according to any one of the first to fourth aspects of the present invention, wherein the content of the repeating unit (a2) is 3 to 30 mol% relative to the total repeating units constituting the copolymer (A). 【0176】 A resin composition according to the sixth aspect of the present invention is a resin composition according to any one of the first to fifth aspects of the present invention, wherein the content of the repeating unit (a3) ​​is 5 to 80 mol% with respect to the total repeating units constituting the copolymer (A). 【0177】A resin composition according to the seventh aspect of the present invention is a resin composition according to any one of the first to sixth aspects of the present invention, wherein the content of the repeating unit (b1) is 5 mol% or more and less than 98 mol% of the total of the repeating unit (b1) and the repeating unit (b2). 【0178】 The eighth aspect of the present invention is a resin composition according to any one of the first to seven aspects of the present invention, wherein the content of the repeating unit (b2) is 2 mol% or more and less than 95 mol% of the total of the repeating unit (b1) and the repeating unit (b2). 【0179】 A prepreg according to the ninth aspect of the present invention is a prepreg comprising a resin composition according to any one of the first to eight aspects of the present invention or a semi-cured product of the resin composition and a fibrous substrate. 【0180】 A resin-coated film according to the tenth aspect of the present invention is a resin-coated film comprising a resin layer containing a resin composition according to any one of the first to eight aspects of the present invention or a semi-cured product of the resin composition, and a support film. 【0181】 A resin-coated metal foil according to the eleventh aspect of the present invention is a resin-coated metal foil comprising a resin layer containing a resin composition according to any one of the first to eight aspects of the present invention or a semi-cured product of the resin composition, and a metal foil. 【0182】 A metal-clad laminate according to the twelfth aspect of the present invention is a metal-clad laminate comprising an insulating layer containing a cured product of a resin composition according to any one of the first to eight aspects of the present invention, and a metal foil. 【0183】 A metal-clad laminate according to a thirteenth aspect of the present invention is a metal-clad laminate comprising an insulating layer containing a cured prepreg according to a ninth aspect of the present invention and a metal foil. 【0184】 A wiring board according to a fourteenth aspect of the present invention is a wiring board comprising an insulating layer containing a cured resin composition according to any one of the first to eight aspects of the present invention, and wiring. 【0185】A wiring board according to the 15th aspect of the present invention is a wiring board comprising an insulating layer containing a cured prepreg according to the 9th aspect of the present invention and wiring. 【0186】 According to the present invention, it is possible to provide a resin composition that yields a cured product with low dielectric properties even after heating, and in which fluctuations in dielectric properties and mass due to temperature changes are suppressed. Furthermore, according to the present invention, it is possible to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using the resin composition. 【0187】 The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited thereto. 【0188】 [Examples 1, 2, 1, and 2] In these examples, each component used in preparing the resin composition will be described. 【0189】 (Copolymer (A)) As the copolymer (A), a linear copolymer obtained by the following reaction was used. 【0190】 1.5 moles (228.9 g) of vinyl benzyl chloride (CMS-14, manufactured by AGC Seimi Chemical Co., Ltd.), 1.8 moles (472.1 g) of triphenylphosphine, and 622.4 g of dimethylformamide were placed in a 2.0 L reactor and reacted under nitrogen conditions at 70°C for 3 hours, resulting in the precipitation of a white solid. The precipitated solid was thoroughly washed with acetone and then dried under reduced pressure at 92°C. This yielded 490 g of solid (vinyl benzyltriphenylphosphonium chloride). 【0191】 18.5 g of styrene, 10.1 g of the aforementioned solid (vinylbenzyltriphenylphosphonium chloride), 6.3 g of acenaphthylene, 7.3 g of 2,4-diphenyl-4-methyl-1-pentene, 2.65 g of 2,2'-azobis(2,4,4-trimethylpentane), and 81.5 g of dimethylformamide were placed in a 500 mL reactor and reacted at 120°C under nitrogen conditions for 1.5 hours. 【0192】126.3 g of the obtained reaction solution, 126.3 g of toluene, 23.7 g of 37% by mass formalin, and 29.3 g of 28% by mass aqueous potassium hydroxide solution were placed in a 500 mL reactor and reacted at room temperature for 4 hours. The obtained reaction solution was diluted with toluene, and the organic layer was washed with distilled water and isopropyl alcohol. The washed organic layer was dehydrated and concentrated, and then 13.9 g of anhydrous magnesium chloride was added and the mixture was stirred at 65°C for 2 hours. Solid matter was removed by filtration, and the filtrate diluted with toluene was reprecipitation in methanol. The solid was then removed by filtration, and the removed solid was dried under reduced pressure at 60°C. The dried solid was weighed to confirm that 16.5 g of solid was obtained. 【0193】 The obtained solid (copolymer (A)) was dissolved in tetrahydrofuran, and the weight-average molecular weight Mw in polystyrene equivalent was measured by gel permeation chromatography (GPC) (Prominence, Shimadzu Corporation) using four columns (Shodex GPC columns KF-601, KF-602, KF-603, and KF-604, manufactured by Showa Denko K.K.) linked together, with polystyrene gel as the packing material. The column oven temperature was 40°C, the THF flow rate was 0.6 mL / min, the sample concentration was 0.1% by mass, and the sample injection volume was 10 μL. A differential refractive index detector (Shodex RI-504, manufactured by Showa Denko K.K.) was used. As a result of this measurement, the weight-average molecular weight Mw of the obtained solid (copolymer (A)) was 2600. 【0194】 The obtained solid (copolymer (A)) is dissolved in deuterated chloroform and subjected to nuclear magnetic resonance (NEM) using a nuclear magnetic resonance spectrometer (manufactured by JEOL Ltd.). １¹H-NMR measurements were performed to determine the molar ratio of repeating units in the obtained solid. Specifically, the molar ratios of repeating units derived from styrene (repeating unit (a1) represented by formula (1) above), repeating units derived from divinylbenzene (repeating unit (a2) derived from divinyl aromatic compounds), and repeating units derived from acenaphthylene (repeating unit (a3) ​​represented by formula (2) above) were determined. From the determined molar ratios, the content of repeating units derived from styrene (styrene ratio), the content of repeating units corresponding to divinylbenzene (divinylbenzene ratio), and the content of repeating units corresponding to acenaphthylene (acenaphthylene ratio) were calculated for all repeating units constituting the copolymer (A). As a result, the styrene ratio was 64.7 mol%, the divinylbenzene ratio was 15.0 mol%, and the acenaphthylene ratio was 20.3 mol%. 【0195】 (Copolymer (B)) As the copolymer (B), a polyfunctional vinyl aromatic copolymer obtained by the following reaction was used. 【0196】 3.0 moles (390.6 g) of divinylbenzene, 1.8 moles (229.4 g) of ethylvinylbenzene, 10.2 moles (1066.3 g) of styrene, and 15.0 moles (1532.0 g) of n-propyl acetate were placed in a 5.0 L reactor. 600 mmol of a diethyl ether complex of boron trifluoride was added at 70°C, and the reaction was allowed to proceed for 4 hours. Afterward, to stop the reaction, an aqueous sodium bicarbonate solution was added to the resulting reaction solution, followed by washing the oil layer three times with pure water. The solid was then recovered by defloration under reduced pressure at 60°C. The obtained solid was weighed to confirm that 896.7 g of solid was obtained. 【0197】 The molecular weight and molecular weight distribution of the obtained solid (polymer) were measured using a GPC (HLC-8120GPC manufactured by Tosoh Corporation), with tetrahydrofuran as the solvent, a flow rate of 1.0 ml / min, a column temperature of 38°C, and a calibration curve using monodisperse polystyrene. As a result, the number-average molecular weight Mn of the obtained solid was 2980, the weight-average molecular weight Mw was 41300, and the Mw / Mn ratio was 13.9. 【0198】The structure of the obtained solid (copolymer) was determined using a JNM-LA600 nuclear magnetic resonance spectrometer manufactured by JEOL Ltd. １３ C-NMR and １ The analysis was performed by 1H-NMR. Chloroform-d was used as the solvent. １ Using this method, the resonance line of tetramethylsilane was used as an internal standard. Furthermore, １３ C-NMR and １ In addition to the H-NMR measurement results, the amount of a specific structural unit introduced was calculated from the data on the total amount of each repeating unit (structural unit) introduced into the solid (polymer) obtained from GC analysis. The amount of pendant vinyl group units contained in the solid (polymer) was then calculated from the amount of this specific structural unit introduced at the end and the number-average molecular weight obtained from the GPC measurement. 【0199】 The obtained solid is as described above. １３ C-NMR and １ By performing 1H-NMR analysis, resonance lines originating from each monomer were observed. Furthermore, based on the measurement results of each NMR analysis and GC analysis, it was determined that this solid was copolymer (B) (polyfunctional vinyl aromatic copolymer). The repeating units of this polyfunctional vinyl aromatic copolymer were calculated as follows based on the measurement results of each NMR analysis and GC analysis. 【0200】 The repeating units derived from divinylbenzene (repeating units derived from divinyl aromatic compounds (b2)) accounted for 30.4 mol% (33.1 mass%). Of these, the repeating units having residual vinyl groups derived from divinylbenzene (repeating units having unsaturated groups represented by formula (8) above (b2-1)) accounted for 23.9 mol% (25.9 mass%). The repeating units derived from styrene (b1-1) accounted for 57.4 mol% (52.7 mass%). The repeating units derived from ethylvinylbenzene (repeating units derived from monovinyl aromatic compounds other than styrene (b1-2)) accounted for 12.2 mol% (14.2 mass%). Therefore, the repeating units derived from monovinyl aromatic compounds (b1) accounted for 69.6 mol% (66.9 mass%). The repeating unit represented by formula (2) above (a3) ​​accounted for 0 mol% (0 mass%). 【0201】 [Preparation Method] First, the composition (parts by mass) shown in Table 1 was added to toluene so that the solid content concentration was 50% by mass, and the mixture was mixed. The mixture was stirred for 60 minutes. By doing so, a varnish-like resin composition (varnish) was obtained. 【0202】 Next, the prepreg was obtained as follows. 【0203】 The obtained varnish was impregnated into a fibrous substrate (glass cloth: #1078 type, L2 glass, manufactured by Asahi Kasei Corporation), and then heated and dried at 120°C for 5 minutes to produce a prepreg. At that time, the content of the components constituting the resin in the prepreg (resin content) was adjusted to approximately 63% by mass. Furthermore, the thickness after curing was adjusted to 90 μm. 【0204】 An evaluation substrate (metal-clad laminate) was obtained in the following manner. 【0205】 Two of the obtained prepregs were stacked together, and 18 μm thick copper foil (CF-T4X-SV-18 manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd.) was placed on both sides. This was used as the pressure-bearing body, and it was heated to a temperature of 220°C at a heating rate of 3°C / min. By heating and pressurizing it at 220°C for 120 minutes under a pressure of 1 MPa, an evaluation substrate (metal-clad laminate) with a resin layer thickness of approximately 180 μm was obtained, with copper foil bonded to both sides. 【0206】 The evaluation substrate prepared as described above was evaluated using the method shown below. 【0207】 [Dielectric Properties (Dielectric Loss Tangent Df Before Heat Treatment and Dielectric Loss Tangent Df After Heat Treatment)] (Dielectric Loss Tangent Df Before Heat Treatment) The copper foil was etched off from the evaluation substrate. The substrate obtained in this way was used as a test piece, and the dielectric loss tangent at 10 GHz was measured using the resonator method. Specifically, a split cylinder resonator (CR710 manufactured by EM Lab Co., Ltd.) was used to measure the dielectric loss tangent (Df) of the test piece at 10 GHz. This was defined as the dielectric loss tangent Df before heat treatment. If the measured dielectric loss tangent Df before heat treatment was 0.0012 or less, it was judged to be "pass". 【0208】(Dielectric Loss Tangent Df after Heat Treatment) Next, the substrate obtained by etching off the copper foil from the evaluation substrate was heat-treated at 130°C for 120 hours. This heat-treated substrate was used as a test piece, and the dielectric loss tangent at 10 GHz was measured using the same resonator method as above. This was defined as the dielectric loss tangent Df after heat treatment. If the measured dielectric loss tangent Df after heat treatment was 0.0015 or less, it was judged to be "pass". 【0209】 [Percentage Change of Df Due to Heat Treatment] From the dielectric loss tangent Df before heat treatment (referred to as "before heat treatment" in the following formula) and the dielectric loss tangent Df after heat treatment (referred to as "after heat treatment" in the following formula), obtained as described above, the percentage change of Df due to heat treatment (referred to as "percentage change" in the following formula) was calculated using the following formula: Percentage change (%) = (After heat treatment - Before heat treatment) / Before heat treatment × 100 【0210】 The smaller the rate of change, the more the fluctuations in dielectric properties such as dielectric loss tangent due to temperature changes are suppressed. If this rate of change is 40% or less, it is judged to be "acceptable". 【0211】 [Glass Transition Temperature (Tg)] An unclad plate, obtained by etching off the copper foil from the evaluation substrate (metal-clad laminate), was used as a test specimen. The Tg of the cured resin composition was measured using a viscoelastic spectrometer "DMA7100" manufactured by Hitachi High-Tech Science Co., Ltd. Dynamic viscoelasticity measurement (DMA) was performed using a tensile module, and the temperature was increased at a heating rate of 5°C / min. The glass transition temperature was measured at this temperature increase. If the measured glass transition temperature was 180°C or higher, it was judged to be "pass". 【0212】[TG-DTA] An unclad plate, obtained by etching away the copper foil from the evaluation substrate (metal-clad laminate), was used as a test specimen, and the mass change was measured using a thermogravimetric-differential thermal analysis (TG-DTA) apparatus (TG-DTA8122 manufactured by Rigaku Corporation). Specifically, the temperature at which the residual mass ratio (mass reduction rate of 3%) reached 97% (mass reduction rate of 3%) relative to the initial mass of the sample piece (3% mass reduction temperature), the temperature at which the residual mass ratio (mass reduction rate of 5%) reached 95% (mass reduction rate of 5%) relative to the initial mass of the sample piece (5% mass reduction temperature), and the reduction rate from the initial mass of the sample piece when heated at 260°C (mass reduction rate at 260°C) were measured. If the measured 3% mass reduction temperature was 330°C or higher, it was judged as "pass". Also, if the measured 5% mass reduction temperature was 350°C or higher, it was judged as "pass". Furthermore, if the measured mass reduction rate at 260°C was 0.5% or less, it was judged as "pass". 【0213】 These results are shown in Table 1. 【0214】 【0215】 Table 1 shows that when copolymer (A) and copolymer (B) are included (Examples 1 and 2), the decrease in mass is suppressed even when heated, compared to when copolymer (A) is included but copolymer (B) is not (Comparative Example 1). This indicates that by including copolymer (B) in addition to copolymer (A), thermal decomposition and other processes are suppressed, and fluctuations in mass due to temperature changes are suppressed. Furthermore, Examples 1 and 2 also had higher glass transition temperatures than Comparative Examples 1 and 2. In addition, Examples 1 and 2 maintained a low dielectric loss tangent even after heating, compared to when copolymer (B) is included but copolymer (A) is not (Comparative Example 2). This indicates that by including copolymer (A) in addition to copolymer (B), not only is the initial dielectric loss tangent low, but oxidative degradation and other processes are suppressed even when heated, and the low dielectric loss tangent is maintained. In other words, dielectric properties such as dielectric loss tangent remain low even after heating, and fluctuations in dielectric properties due to temperature changes are suppressed. 【0216】 This application is based on Japanese Patent Application No. 2024-215841, filed on December 10, 2024, the contents of which are included in this application. 【0217】 Although the present invention has been adequately and sufficiently described above through embodiments, those skilled in the art should recognize that it is easy to modify and / or improve upon the above embodiments. Therefore, unless such modifications or improvements implemented by those skilled in the art fall outside the scope of the claims, such modifications or improvements shall be considered to be included within the scope of the claims. 【0218】 The present invention provides a resin composition that yields a cured product with low dielectric properties even after heating, and in which fluctuations in dielectric properties and mass due to temperature changes are suppressed. Furthermore, the present invention provides 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.

Claims

1. A resin composition comprising a linear copolymer (A) containing a repeating unit (a1) represented by the following formula (1), a repeating unit (a2) derived from a divinyl aromatic compound, and a repeating unit (a3) ​​represented by the following formula (2), and a copolymer (B) containing a repeating unit (b1) derived from a monovinyl aromatic compound and a repeating unit (b2) derived from a divinyl aromatic compound, but not containing a repeating unit represented by the following formula (2). [In formula (1), R １ This represents a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. [In formula (2), R ２ and R ３ Each of these independently represents an alkyl group having 1 to 20 carbon atoms, a halogen atom, an aryl group having 6 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms, and m and n independently represent 0 to 3.

2. The resin composition according to claim 1, wherein the copolymer (B) has a branched structure.

3. The resin composition according to claim 1, wherein the content ratio of copolymer (A) to copolymer (B) is 10:90 to 90:10 by mass.

4. The resin composition according to claim 1, wherein the content of the repeating unit (a1) is 15 to 90 mol% with respect to the total repeating units constituting the copolymer (A).

5. The resin composition according to claim 1, wherein the content of the repeating unit (a2) is 3 to 30 mol% relative to the total repeating units constituting the copolymer (A).

6. The resin composition according to claim 1, wherein the content of the repeating unit (a3) ​​is 5 to 80 mol% with respect to the total repeating units constituting the copolymer (A).

7. The resin composition according to claim 1, wherein the content of the repeating unit (b1) is 5 mol% or more and less than 98 mol% of the total of the repeating unit (b1) and the repeating unit (b2).

8. The resin composition according to claim 1, wherein the content of the repeating unit (b2) is 2 mol% or more and less than 95 mol% of the total of the repeating unit (b1) and the repeating unit (b2).

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

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

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

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

13. A metal-clad laminate comprising an insulating layer containing a cured prepreg according to claim 9, and a metal foil.

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

15. A wiring board comprising an insulating layer containing a cured prepreg according to claim 9, and wiring.

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