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

Abstract

To provide a resin composition, which exhibits moldability to be applicable to a laminated wiring board and can provide a cured product having low dielectric properties, high heat resistance, and resistance to external environment changes and other influences.SOLUTION: An aspect of the present application relates to a resin composition, which contains a polymer having structural units derived from divinylbenzene, structural units derived from ethylvinylbenzene, and structural units derived from styrene in a molecule and a free radical compound, and in which the free radical compound has at least one free radical group selected from the group consisting of compounds having specific structures in the molecule.SELECTED DRAWING: None

Description

[Technical Field]

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

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

[0003] As such a substrate material, for example, a curable composition containing a soluble polyfunctional vinyl aromatic copolymer and a radical polymerization initiator has been reported (Patent Document 1).

[0004] Patent Document 1 discloses that it is possible to obtain a material that has low dielectric properties and can be applied to cutting-edge electrical and electronic fields that require high-performance electrical, thermal, and mechanical properties. It is believed that a wiring board obtained using a curable composition with low dielectric properties such as a dielectric constant and a dielectric loss tangent, as described in Patent Document 1, can reduce loss during signal transmission.

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

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

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

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

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

[0010] [Patent Document 1] International Publication No. 2017 / 115813 Summary of the Invention

[0011] The present invention has been made in view of the above circumstances, and aims to provide a resin composition that can give a cured product having low dielectric properties, high heat resistance, and resistance to the effects of changes in the external environment, and that has moldability that enables application to laminated wiring boards. Another aim of the present invention is to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that are obtainable using the resin composition.

[0012] As a result of extensive investigations, the present inventors have found that the above object can be achieved by the following constitution, and have achieved the present invention through further investigations.

[0013] That is, a resin composition according to one embodiment of the present invention comprises a polymer having a structural unit represented by formula (1) in the molecule, which will be described later, and a free radical compound, and the free radical compound has at least one free radical group in the molecule selected from the group of structures represented by formulas (2), (3), (4), and (5), which will be described later. [Brief explanation of the drawings]

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

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

[0016] [Resin composition] A resin composition according to one embodiment of the present invention comprises a polymer having a structural unit represented by the following formula (1) in the molecule, and a free radical compound, wherein the free radical compound has at least one free radical group selected from the group consisting of structures represented by the following formulas (2), (3), (4), and (5) in the molecule.

[0017] [ka]

[0018] [ka]

[0019] [ka]

[0020] [ka]

[0021] [ka]

[0022] In the above formula (1), Z represents an arylene group, R1 to R3 each independently represent a hydrogen atom or an alkyl group, and R4 to R6 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

[0023] According to the above-mentioned constitution, it is possible to obtain a cured product having low dielectric properties and high heat resistance, which can favorably maintain low dielectric properties even after heat treatment or water absorption treatment, and it is also possible to provide a resin composition having excellent moldability that allows for filling of circuit patterns.Furthermore, according to the present invention, by using the resin composition, it is possible to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board having excellent performance.

[0024] By adding a free radical compound having the structure described above to a resin composition containing the polymer, a cured product can be obtained that has low dielectric properties and high heat resistance and can favorably maintain its low dielectric properties even after heat treatment or water absorption treatment, and a resin composition with excellent moldability can be obtained.

[0025] This is thought to be because the addition of a free radical compound can improve moldability while maintaining the properties of the cured product, such as Tg, to a certain extent.

[0026] First, each component of the resin composition of the present embodiment will be described.

[0027] (polymer) The polymer is not particularly limited as long as it has a structural unit represented by formula (1) in the molecule. Furthermore, as long as the polymer has a structural unit represented by formula (1) in the molecule, it may have a structural unit other than the structural unit represented by formula (1). Furthermore, the polymer may contain a repeating unit in which the structural unit represented by formula (1) is repeatedly bonded, or may be a polymer in which a repeating unit in which the structural unit represented by formula (1) is repeatedly bonded and a repeating unit in which a structural unit other than the structural unit represented by formula (1) is repeatedly bonded are randomly bonded. That is, when the polymer has a structural unit other than the structural unit represented by formula (1), it may be a block copolymer or a random copolymer.

[0028] The arylene group represented by Z in formula (1) is not particularly limited. Examples of the arylene group include monocyclic aromatic groups such as phenylene groups, and polycyclic aromatic groups in which the aromatic ring is not monocyclic but polycyclic aromatic such as naphthalene rings. The arylene group also includes derivatives in which the hydrogen atom bonded to the aromatic ring is substituted with a functional group such as an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0029] The alkyl group represented by R1 to R3 in the formula (1) is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0030] The alkyl group having 1 to 6 carbon atoms represented by R4 to R6 in the formula (1) is not particularly limited, and specific examples include a methyl group, an ethyl group, a propyl group, and a hexyl group.

[0031] The polymer preferably contains an aromatic polymer having, as the structural unit represented by formula (1), a structural unit derived from a bifunctional aromatic compound in which two carbon-carbon unsaturated double bonds are bonded to an aromatic ring. The structural unit derived from the bifunctional aromatic compound is a structural unit obtained by polymerizing the bifunctional aromatic compound. In this specification, the aromatic polymer is also referred to as a divinyl aromatic polymer.

[0032] The bifunctional aromatic compound is not particularly limited as long as it is a bifunctional aromatic compound having two carbon-carbon unsaturated double bonds bonded to an aromatic ring. Examples of the bifunctional aromatic compound include m-divinylbenzene, p-divinylbenzene, 1,2-diisopropenylbenzene, 1,3-diisopropenylbenzene, 1,4-diisopropenylbenzene, 1,3-divinylnaphthalene, 1,8-divinylnaphthalene, 1,4-divinylnaphthalene, 1,5-divinylnaphthalene, 2,3-divinylnaphthalene, 2,7-divinylnaphthalene, and 2,6-divinylnaphthalene. Examples of the bifunctional aromatic compound include 4,4'-divinylbiphenyl, 4,3'-divinylbiphenyl, 4,2'-divinylbiphenyl, 3,2'-divinylbiphenyl, 3,3'-divinylbiphenyl, 2,2'-divinylbiphenyl, 2,4-divinylbiphenyl, 1,2-divinyl-3,4-dimethylbenzene, 1,3-divinyl-4,5,8-tributylnaphthalene, and 2,2'-divinyl-4-ethyl-4'-propylbiphenyl. These may be used alone or in combination of two or more. Among these, the bifunctional aromatic compound is preferably a divinylbenzene such as m-divinylbenzene or p-divinylbenzene, and more preferably p-divinylbenzene.

[0033] The aromatic polymer may have not only the structural unit derived from the bifunctional aromatic compound but also other structural units. Examples of such other structural units include a structural unit derived from a monofunctional aromatic compound having one carbon-carbon unsaturated double bond bonded to an aromatic ring, a structural unit derived from a trifunctional aromatic compound having three carbon-carbon unsaturated double bonds bonded to an aromatic ring, a structural unit derived from indenes, and a structural unit derived from acenaphthylenes. The structural unit derived from the monofunctional aromatic compound is a structural unit obtained by polymerizing the monofunctional aromatic compound. The structural unit derived from the trifunctional aromatic compound is a structural unit obtained by polymerizing the trifunctional aromatic compound. The structural unit derived from indenes is a structural unit obtained by polymerizing indenes. The structural unit derived from acenaphthylenes is a structural unit obtained by polymerizing acenaphthylenes.

[0034] The monofunctional aromatic compound may have one carbon-carbon unsaturated double bond bonded to an aromatic ring, and the aromatic ring may have a group other than the carbon-carbon unsaturated double bond bonded to it. Examples of the monofunctional aromatic compound include a monofunctional aromatic compound having one carbon-carbon unsaturated double bond bonded to an aromatic ring and no group other than the carbon-carbon unsaturated double bond bonded to it, and a monofunctional aromatic compound having one carbon-carbon unsaturated double bond bonded to an aromatic ring and further having an alkyl group such as an ethyl group bonded to the aromatic ring.

[0035] Examples of monofunctional aromatic compounds having one carbon-carbon unsaturated double bond bonded to an aromatic ring and no groups other than this carbon-carbon unsaturated double bond include styrene, 2-vinylbiphenyl, 3-vinylbiphenyl, 4-vinylbiphenyl, 1-vinylnaphthalene, 2-vinylnaphthalene, and α-alkyl-substituted styrenes. Examples of α-alkyl-substituted styrenes include α-methylstyrene, α-ethylstyrene, α-propylstyrene, α-n-butylstyrene, α-isobutylstyrene, α-t-butylstyrene, α-n-pentylstyrene, α-2-methylbutylstyrene, α-3-methylbutyl-2-styrene, α-t-butylstyrene, α-t-butylstyrene, α-n-pentylstyrene, α-2-methylbutylstyrene, α-3-methylbutylstyrene, α-t-pentylstyrene, and α-n-hexylstyrene. Examples of such styrene include ethylene, α-2-methylpentylstyrene, α-3-methylpentylstyrene, α-1-methylpentylstyrene, α-2,2-dimethylbutylstyrene, α-2,3-dimethylbutylstyrene, α-2,4-dimethylbutylstyrene, α-3,3-dimethylbutylstyrene, α-3,4-dimethylbutylstyrene, α-4,4-dimethylbutylstyrene, α-2-ethylbutylstyrene, α-1-ethylbutylstyrene, α-cyclohexylstyrene, and α-cyclohexylstyrene. These may be used alone or in combination of two or more.

[0036] Examples of monofunctional aromatic compounds in which one carbon-carbon unsaturated double bond is bonded to an aromatic ring and an alkyl group is further bonded to the aromatic ring include nuclear alkyl-substituted aromatic compounds and alkoxy-substituted styrenes.

[0037] Examples of the nuclear alkyl-substituted aromatic compounds include ethyl vinyl aromatic compounds in which the alkyl group bonded to the aromatic ring is an ethyl group, nuclear alkyl-substituted styrenes in which an alkyl group is bonded to styrene as the aromatic ring, and nuclear alkyl-substituted aromatic compounds other than the ethyl vinyl aromatic compounds and the nuclear alkyl-substituted styrenes (other nuclear alkyl-substituted aromatic compounds).

[0038] Examples of the ethyl vinyl aromatic compounds include o-ethyl vinylbenzene, m-ethyl vinylbenzene, p-ethyl vinylbenzene, 2-vinyl-2'-ethyl biphenyl, 2-vinyl-3'-ethyl biphenyl, 2-vinyl-4'-ethyl biphenyl, 3-vinyl-2'-ethyl biphenyl, 3-vinyl-3'-ethyl biphenyl, 3-vinyl-4'-ethyl biphenyl, 4-vinyl-2'-ethyl biphenyl, 4-vinyl-3'-ethyl biphenyl, 4-vinyl-4'-ethyl biphenyl, 1-vinyl-2-ethyl Examples thereof include naphthalene, 1-vinyl-3-ethylnaphthalene, 1-vinyl-4-ethylnaphthalene, 1-vinyl-5-ethylnaphthalene, 1-vinyl-6-ethylnaphthalene, 1-vinyl-7-ethylnaphthalene, 1-vinyl-8-ethylnaphthalene, 2-vinyl-1-ethylnaphthalene, 2-vinyl-3-ethylnaphthalene, 2-vinyl-4-ethylnaphthalene, 2-vinyl-5-ethylnaphthalene, 2-vinyl-6-ethylnaphthalene, 2-vinyl-7-ethylnaphthalene, and 2-vinyl-8-ethylnaphthalene.

[0039] Examples of the nuclear alkyl-substituted styrenes include m-methylstyrene, p-methylstyrene, m-propylstyrene, p-propylstyrene, mn-butylstyrene, pn-butylstyrene, mt-butylstyrene, pt-butylstyrene, mn-hexylstyrene, pn-hexylstyrene, m-cyclohexylstyrene, and p-cyclohexylstyrene.

[0040] Examples of the other nuclear alkyl-substituted aromatic compounds include 2-vinyl-2'-propylbiphenyl, 2-vinyl-3'-propylbiphenyl, 2-vinyl-4'-propylbiphenyl, 3-vinyl-2'-propylbiphenyl, 3-vinyl-3'-propylbiphenyl, 3-vinyl-4'-propylbiphenyl, 4-vinyl-2'-propylbiphenyl, 4-vinyl-3'-propylbiphenyl, 4-vinyl-4'-propylbiphenyl, 1-vinyl-2-propylnaphthalene, 1-vinyl-3-propylnaphthalene, and 1-vinyl-3-propylnaphthalene. Examples of suitable propyl naphthalene include 1-vinyl-4-propyl naphthalene, 1-vinyl-5-propyl naphthalene, 1-vinyl-6-propyl naphthalene, 1-vinyl-7-propyl naphthalene, 1-vinyl-8-propyl naphthalene, 2-vinyl-1-propyl naphthalene, 2-vinyl-3-propyl naphthalene, 2-vinyl-4-propyl naphthalene, 2-vinyl-5-propyl naphthalene, 2-vinyl-6-propyl naphthalene, 2-vinyl-7-propyl naphthalene, and 2-vinyl-8-propyl naphthalene.

[0041] Examples of the alkoxy-substituted styrenes include o-ethoxystyrene, m-ethoxystyrene, p-ethoxystyrene, o-propoxystyrene, m-propoxystyrene, p-propoxystyrene, on-butoxystyrene, mn-butoxystyrene, pn-butoxystyrene, o-isobutoxystyrene, m-isobutoxystyrene, p-isobutoxystyrene, ot-butoxystyrene, mt-butoxystyrene, pt-butoxystyrene, on-pentoxystyrene, mn-pentoxystyrene, pn-pentoxystyrene, and α-methyl-o-butoxystyrene. , α-methyl-m-butoxystyrene, α-methyl-p-butoxystyrene, ot-pentoxystyrene, mt-pentoxystyrene, pt-pentoxystyrene, on-hexoxystyrene, mn-hexoxystyrene, pn-hexoxystyrene, α-methyl-o-pentoxystyrene, α-methyl-m-pentoxystyrene, α-methyl-p-pentoxystyrene, o-cyclohexoxystyrene, m-cyclohexoxystyrene, p-cyclohexoxystyrene, o-phenoxystyrene, m-phenoxystyrene, and p-phenoxystyrene.

[0042] The monofunctional aromatic compound may be any of the exemplified compounds, or may be a combination of two or more of them. Among the exemplified compounds, styrene and p-ethylvinylbenzene are preferred as the monofunctional aromatic compound.

[0043] Examples of trifunctional aromatic compounds having three carbon-carbon unsaturated double bonds bonded to an aromatic ring include 1,2,4-trivinylbenzene, 1,3,5-trivinylbenzene, 1,2,4-triisopropenylbenzene, 1,3,5-triisopropenylbenzene, 1,3,5-trivinylnaphthalene, and 3,5,4'-trivinylbiphenyl. The trifunctional aromatic compounds may be used alone or in combination of two or more of the above-mentioned compounds.

[0044] Examples of the indenes include indene, alkyl-substituted indenes, and alkoxyindenes. Examples of the alkyl-substituted indenes include methylindene, ethylindene, propylindene, butylindene, t-butylindene, sec-butylindene, n-pentylindene, 2-methyl-butylindene, 3-methyl-butylindene, n-hexylindene, 2-methyl-pentylindene, 3-methyl-pentylindene, and 4-methyl-pentylindene. Examples of the alkoxyindenes include methoxyindene, ethoxyindene, butoxyindene, butoxyindene, t-butoxyindene, sec-butoxyindene, n-pentoxyindene, 2-methyl-butoxyindene, 3-methyl-butoxyindene, n-hexoxyindene, 2-methyl-pentoxyindene, 3-methyl-pentoxyindene, 4-methyl-pentoxyindene, etc. As the indenes, the exemplified compounds may be used alone or in combination of two or more.

[0045] Examples of the acenaphthylenes include acenaphthylene, alkylacenaphthylenes, halogenated acenaphthylenes, and phenylacenaphthylenes. Examples of the alkylacenaphthylenes include 1-methylacenaphthylene, 3-methylacenaphthylene, 4-methylacenaphthylene, 5-methylacenaphthylene, 1-ethylacenaphthylene, 3-ethylacenaphthylene, 4-ethylacenaphthylene, and 5-ethylacenaphthylene. Examples of the halogenated acenaphthylenes include 1-chloroacenaphthylene, 3-chloroacenaphthylene, 4-chloroacenaphthylene, 5-chloroacenaphthylene, 1-bromoacenaphthylene, 3-bromoacenaphthylene, 4-bromoacenaphthylene, and 5-bromoacenaphthylene. Examples of the phenylacenaphthylenes include 1-phenylacenaphthylene, 3-phenylacenaphthylene, 4-phenylacenaphthylene, 5-phenylacenaphthylene, etc. As the acenaphthylenes, the exemplified compounds may be used alone or in combination of two or more.

[0046] When the aromatic polymer has not only the structural unit derived from the bifunctional aromatic compound but also other structural units, it is a copolymer of the structural unit derived from the bifunctional aromatic compound and other structural units such as the structural unit derived from the monofunctional aromatic compound, etc. This copolymer may be a block copolymer or a random copolymer.

[0047] As described above, the polymer is not particularly limited as long as it has a structural unit represented by formula (1) in the molecule. The structural unit represented by formula (1) preferably includes a structural unit represented by formula (9) below. That is, the polymer is preferably a polymer having a structural unit represented by formula (2) below in the molecule.

[0048] [ka]

[0049] In formula (9), R4 to R6 are the same as R4 to R6 in formula (1). Specifically, R4 to R6 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. R7 represents an arylene group having 6 to 12 carbon atoms.

[0050] The arylene group having 6 to 12 carbon atoms in the formula (9) is not particularly limited. Examples of the arylene group include monocyclic aromatic groups such as a phenylene group, and bicyclic aromatic groups in which the aromatic ring is not monocyclic but bicyclic aromatic rings such as a naphthalene ring. The arylene group also includes derivatives in which a hydrogen atom bonded to the aromatic ring is substituted with a functional group such as an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0051] The structural unit represented by the formula (9) preferably contains a structural unit represented by the following formula (10). That is, in the structural unit represented by the formula (9), R7 is preferably a phenylene group. Furthermore, among the phenylene groups, a p-phenylene group is more preferred.

[0052] [ka]

[0053] In formula (10), R4 to R6 are the same as R4 to R6 in formula (1). Specifically, R4 to R6 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

[0054] The polymer preferably includes a polymer further having a structural unit represented by the following formula (11) in the molecule. That is, the polymer preferably includes, as the structural unit represented by the following formula (11), a structural unit derived from a monofunctional aromatic compound in which one carbon-carbon unsaturated double bond is bonded to an aromatic ring. Therefore, the polymer is preferably a polymer having, in the molecule, a structural unit represented by the formula (1) and a structural unit represented by the following formula (11). That is, as long as the polymer has, in the molecule, a structural unit represented by the formula (1) and a structural unit represented by the following formula (11), it may have structural units other than the structural unit represented by the formula (1) and the structural unit represented by the following formula (11) (structural units other than (1) and (11)). The polymer may contain structural units other than those of (1) and (11), or may be a polymer, a block copolymer, or a random copolymer in which a repeating unit in which the structural unit represented by formula (1) is repeatedly bonded, a repeating unit represented by formula (11) below, and a repeating unit in which the structural unit other than those of (1) and (11) is repeatedly bonded are randomly bonded.

[0055] [ka]

[0056] In formula (11), R8~R 10 are independent of each other. That is, R8 to R 10 may be the same group or different groups. 10 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. 11 represents an aryl group.

[0057] In the formula (11), R to R 10 The alkyl group having 1 to 6 carbon atoms represented by R4 to R6 in the formula (1) is not particularly limited, and may be the same as the alkyl group having 1 to 6 carbon atoms represented by R4 to R6 in the formula (11). 10 Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, and a hexyl group.

[0058] In the formula (11), R 11 The aryl group represented by the formula (11) is not particularly limited, and may be an unsubstituted aryl group, or an aryl group in which a hydrogen atom bonded to an aromatic ring is substituted with an alkyl group or the like. The unsubstituted aryl group may be a group in which one hydrogen atom has been removed from an aromatic hydrocarbon having one aromatic ring, or a group in which one hydrogen atom has been removed from an aromatic hydrocarbon having two or more independent aromatic rings (e.g., biphenyl). Examples of the aryl group in the formula (11) include unsubstituted aryl groups having 6 to 12 carbon atoms, and arylene groups having 6 to 18 carbon atoms in which a hydrogen atom of an aryl group having 6 to 12 carbon atoms has been substituted with an alkyl group having 1 to 6 carbon atoms. Examples of the unsubstituted aryl group having 6 to 12 carbon atoms include a phenyl group, a naphthyl group, and a biphenylyl group. The aryl group in the formula (11), i.e., R 11 More specifically, the aryl groups include those listed in Tables 1 and 2 below.

[0059] [Table 1]

[0060] [Table 2]

[0061] The weight-average molecular weight of the polymer is preferably 1500 to 40000, more preferably 1500 to 35000. If the weight-average molecular weight is too low, heat resistance and the like tend to decrease. On the other hand, if the weight-average molecular weight is too high, moldability and the like tend to decrease. Therefore, when the weight-average molecular weight of the resin composition is within the above range, the resin composition will have excellent heat resistance and moldability. Here, the weight-average molecular weight may be measured by a general molecular weight measurement method, and specific examples include values ​​measured using gel permeation chromatography (GPC).

[0062] In the polymer, when the total of the structural units in the polymer is taken as 100 mol%, the molar content of the structural unit represented by formula (1) is preferably a molar content within the above weight average molecular weight range, specifically, preferably 2 to 95 mol%, more preferably 8 to 81 mol%. The molar contents of the structural units represented by formula (9) and the structural units represented by formula (10) are the same as the molar contents of the structural units represented by formula (1), specifically, preferably 2 to 95 mol%, more preferably 8 to 81 mol%. When the polymer has a structural unit represented by formula (1) and a structural unit represented by the following formula (11) in its molecule, the molar content of the structural unit represented by formula (1) is preferably 2 to 95 mol%, more preferably 8 to 81 mol%, and the molar content of the structural unit represented by formula (11) is preferably 5 to 98 mol%, more preferably 19 to 92 mol%.

[0063] In the polymer, the average number of structural units represented by formula (1) is preferably a number within the range of the weight average molecular weight, specifically, preferably 1 to 160, and more preferably 3 to 140. The average number of structural units represented by formula (9) and the average number of structural units represented by formula (10) are the same as the average number of structural units represented by formula (1), specifically, preferably 1 to 160, and more preferably 3 to 140. In addition, when the polymer has structural units represented by formula (1) and structural units represented by the following formula (11) in the molecule, the average number of structural units represented by formula (1) is preferably 1 to 160, and more preferably 3 to 140, and the average number of structural units represented by formula (11) is preferably 2 to 350, and more preferably 4 to 300.

[0064] Specific examples of the polymer include a polymer containing a structural unit represented by the following formula (12) in the molecule and further containing at least one of a structural unit represented by the following formula (13) and a structural unit represented by the following formula (14): This polymer may be a block copolymer or a random copolymer.

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] In a polymer containing a structural unit represented by formula (13) in the molecule and further containing at least one of a structural unit represented by formula (12) and a structural unit represented by formula (14), the molar contents of the structural unit represented by formula (12), the structural unit represented by formula (13), and the structural unit represented by formula (14) are preferably 0 to 92 mol%, 8 to 54 mol%, and 0 to 89 mol%, respectively. The average number of structural units represented by formula (12) is preferably 0 to 350, the average number of structural units represented by formula (13) is preferably 1 to 160, and the average number of structural units represented by formula (14) is preferably 0 to 270.

[0069] The equivalent weight of the vinyl group contained in the structural unit of the polymer represented by formula (1) where R1 to R3 are hydrogen atoms is preferably 250 to 1200, more preferably 300 to 1100. If the equivalent weight is too low, the vinyl group content will be too high, resulting in excessive reactivity, which may result in problems such as reduced shelf life and reduced fluidity of the resin composition. If a resin composition with too low an equivalent weight is used, poor fluidity may result in molding defects such as the generation of voids during multilayer molding, leading to moldability issues such as difficulty in obtaining reliable wiring boards. If the equivalent weight is too high, the vinyl group content will be too low, which tends to result in insufficient heat resistance of the cured product. Therefore, when the equivalent weight is within the above range, excellent heat resistance and moldability are achieved. The equivalent weight of the vinyl group contained in the structural unit represented by formula (1) where R1 to R3 are hydrogen atoms is the so-called vinyl equivalent.

[0070] (free radical compounds) The free radical compound used in this embodiment is not particularly limited as long as it is a free radical compound having at least one of the structures represented by the above formulas (2) to (5). By including such a free radical compound, the resin composition of this embodiment is believed to be able to exhibit excellent moldability (moldability that allows circuit patterns to be filled) while retaining properties such as low dielectric properties and heat resistance. Furthermore, it is believed that a cured product can be obtained that can favorably maintain low dielectric properties even after heat treatment or water absorption treatment.

[0071] Preferably, the free radical compound of this embodiment includes at least one compound selected from the compounds represented by the following formulas (6) to (8).

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] In the formula (6) and the formula (7), X A and X B each independently represents a hydrogen atom, an amino group, a cyano group, a hydroxy group, an isothiocyanate group, a methoxy group, a carboxy group, a carbonyl group, an amido group, a benzoyloxy group, or an ether bond.

[0076] More specific examples of these include 4-acetamido, 4-glycidyloxy, 4-benzoyloxy, 4-(2-iodoacetamido), 4-[2-[2-(4-iodophenoxy)ethoxy]carbonyl]benzoyloxy, 4-methacryloyloxy, 4-oxo, and 4-propargyloxy.

[0077] In addition, in the formula (8), X C represents an alkylene group, an aromatic structure, a carbonyl group, an amide group, or an ether bond.

[0078] The alkylene group may have a linear, side-chain, and / or cyclic structure, and the length of the linear and side chains is not particularly limited. If the number of carbon atoms is too large, the solubility of the resin component in a solvent may decrease, so for example, the number of carbon atoms is preferably 16 or less, and particularly preferably about 8 or less.

[0079] When the alkylene group has a cyclic structure, examples thereof include a seven-membered ring, a six-membered ring, and a five-membered ring.

[0080] Examples of the aromatic structure include a phenyl group, a pyrrole group, and a thiazole group.

[0081] More specific free radical compounds preferably used in this embodiment include 4-amino-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-amino-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-carboxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-cyano-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-glycidyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxylbenzoate free radical, and 4-isothiocyanato-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-(2-iodoacetamido)-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-[2-[2-(4-iodophenoxy)ethoxy]carbonyl]benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-oxo-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-oxo-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 2,2,6,6-tetramethyl-4-(2-propynyloxy)piperidine 1-oxyl Free radical, 2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4,5-dihydro-4,4,5,5-tetramethyl-2-phenyl-1H-imidazol-1-yloxy-1-oxide, bis(2,2,6,6-tetramethyl-4-piperidyl-1-oxyl) sebacate, 3-carboxy-2,2,5,5-tetramethylpyrrolidine 1-oxyl Free radical, 4-(2-chloroacetamido)-2,2,6,Examples include 6-tetramethylpiperidine 1-oxyl free radical, 2-(4-nitrophenyl)-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl free radical, 2-(14-carboxytetradecyl)-2-ethyl-4,4-dimethyl-3-oxazolidinyloxy free radical, and 1,1-diphenyl-2-picrylhydrazyl free radical.

[0082] Various free radical compounds have been mentioned above, and these may be used alone or in combination of two or more.

[0083] The free radical compound of this embodiment as described above may be commercially available and is available from, for example, Tokyo Chemical Industry Co., Ltd.

[0084] (hardening agent) The curing agent is not particularly limited as long as it can react with the polymer to cure the resin composition containing the polymer. Examples of the curing agent include curing agents having at least one functional group in the molecule that contributes to the reaction with the polymer. Examples of the curing agent include styrene, styrene derivatives, compounds having an acryloyl group in the molecule, compounds having a methacryloyl group in the molecule, compounds having a vinyl group in the molecule, compounds having an allyl group in the molecule, compounds having a maleimide group in the molecule, and compounds having an acenaphthylene structure in the molecule.

[0085] Examples of the styrene derivatives include bromostyrene and dibromostyrene.

[0086] The compound having an acryloyl group in the molecule is an acrylate compound. Examples of the acrylate compound include a monofunctional acrylate compound having one acryloyl group in the molecule and a polyfunctional acrylate compound having two or more acryloyl groups in the molecule. Examples of the monofunctional acrylate compound include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. Examples of the polyfunctional acrylate compound include tricyclodecane dimethanol diacrylate.

[0087] The compound having a methacryloyl group in the molecule is a methacrylate compound. Examples of the methacrylate compound include monofunctional methacrylate compounds having one methacryloyl group in the molecule and polyfunctional methacrylate compounds having two or more methacryloyl groups in the molecule. Examples of the monofunctional methacrylate compound include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Examples of the polyfunctional methacrylate compound include tricyclodecane dimethanol dimethacrylate.

[0088] The compound having a vinyl group in the molecule is a vinyl compound. Examples of the vinyl compound include a monofunctional vinyl compound (monovinyl compound) having one vinyl group in the molecule, and a polyfunctional vinyl compound having two or more vinyl groups in the molecule. Examples of the polyfunctional vinyl compound include divinylbenzene and polybutadiene.

[0089] The compound having an allyl group in the molecule is an allyl compound. Examples of the allyl compound include a monofunctional allyl compound having one allyl group in the molecule and a polyfunctional allyl compound having two or more allyl groups in the molecule. Examples of the polyfunctional allyl compound include diallyl phthalate (DAP).

[0090] The compound having a maleimide group in the molecule is a maleimide compound. Examples of the maleimide compound include a monofunctional maleimide compound having one maleimide group in the molecule, a polyfunctional maleimide compound having two or more maleimide groups in the molecule, and a modified maleimide compound. Examples of the modified maleimide compound include a modified maleimide compound in which a portion of the molecule is modified with an amine compound, a modified maleimide compound in which a portion of the molecule is modified with a silicone compound, and a modified maleimide compound in which a portion of the molecule is modified with an amine compound and a silicone compound.

[0091] The compound having an acenaphthylene structure in the molecule is an acenaphthylene compound. Examples of the acenaphthylene compound include acenaphthylene, alkylacenaphthylenes, halogenated acenaphthylenes, and phenylacenaphthylenes. Examples of the alkylacenaphthylenes include 1-methylacenaphthylene, 3-methylacenaphthylene, 4-methylacenaphthylene, 5-methylacenaphthylene, 1-ethylacenaphthylene, 3-ethylacenaphthylene, 4-ethylacenaphthylene, and 5-ethylacenaphthylene. Examples of the halogenated acenaphthylenes include 1-chloroacenaphthylene, 3-chloroacenaphthylene, 4-chloroacenaphthylene, 5-chloroacenaphthylene, 1-bromoacenaphthylene, 3-bromoacenaphthylene, 4-bromoacenaphthylene, and 5-bromoacenaphthylene. Examples of the phenylacenaphthylenes include 1-phenylacenaphthylene, 3-phenylacenaphthylene, 4-phenylacenaphthylene, and 5-phenylacenaphthylene. The acenaphthylene compound may be a monofunctional acenaphthylene compound having one acenaphthylene structure in the molecule, as described above, or a polyfunctional acenaphthylene compound having two or more acenaphthylene structures in the molecule.

[0092] Among the above, preferred curing agents include, for example, polyfunctional acrylate compounds having two or more acryloyl groups in the molecule, polyfunctional methacrylate compounds having two or more methacryloyl groups in the molecule, polyfunctional vinyl compounds having two or more vinyl groups in the molecule, styrene derivatives, allyl compounds having an allyl group in the molecule, maleimide compounds having a maleimide group in the molecule, and acenaphthylene compounds having an acenaphthylene structure in the molecule.

[0093] The curing agent may be used alone or in combination of two or more kinds.

[0094] The curing agent preferably has a weight-average molecular weight of 100 to 5000, more preferably 100 to 4000, and even more preferably 100 to 3000. If the curing agent has a weight-average molecular weight that is too low, the curing agent may be more likely to volatilize from the resin composition's blended components. If the curing agent has a weight-average molecular weight that is too high, the viscosity of the resin composition varnish or the melt viscosity during heat molding may be too high. Therefore, when the weight-average molecular weight of the curing agent is within this range, a resin composition with excellent heat resistance can be obtained. This is thought to be because the resin composition containing the polymer can be favorably cured by reaction with the polymer. The weight-average molecular weight may be measured using a common molecular weight measurement method, specifically, a value measured using gel permeation chromatography (GPC), etc.

[0095] The average number of functional groups per molecule of the curing agent that contribute to the reaction with the polymer (number of functional groups) varies depending on the weight-average molecular weight of the curing agent, but is preferably 1 to 20, and more preferably 2 to 18. If the number of functional groups is too small, it tends to be difficult to obtain sufficient heat resistance of the cured product. On the other hand, if the number of functional groups is too large, the reactivity becomes too high, which may cause problems such as reduced storage stability and reduced fluidity of the resin composition.

[0096] (Reaction initiator) The resin composition according to this embodiment may further contain a reaction initiator (initiator). The curing reaction can proceed even when the resin composition is composed of the modified polyphenylene ether compound and the curing agent. The curing reaction can also proceed when the resin composition contains only the modified polyphenylene ether compound. However, depending on the process conditions, it may be difficult to raise the temperature high enough for curing to proceed, so a reaction initiator may be added.

[0097] The reaction initiator is not particularly limited as long as it can accelerate the curing reaction of the modified polyphenylene ether compound (and the curing agent, if any). Specific examples include metal oxides, azo compounds, and organic peroxides.

[0098] Specific examples of metal oxides include metal carboxylates.

[0099] Examples of organic peroxides include α,α'-di(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, benzoyl peroxide, 3,3',5,5'-tetramethyl-1,4-diphenoquinone, chloranil, 2,4,6-tri-t-butylphenoxyl, t-butylperoxyisopropyl monocarbonate, and azobisisobutyronitrile.

[0100] Specific examples of the azo compound include 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(N-butyl-2-methylpropionamide), and 2,2'-azobis(2-methylbutyronitrile).

[0101] Among these, preferred reaction initiators are 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(N-butyl-2-methylpropionamide), etc. These reaction initiators have little effect on dielectric properties. In addition, because the reaction initiation temperature is relatively high, promotion of the curing reaction can be suppressed when curing is not required, such as during prepreg drying, which has the advantage of suppressing deterioration in the shelf life of the resin composition.

[0102] The above-mentioned reaction initiators may be used alone or in combination of two or more kinds.

[0103] (Inorganic filler) The resin composition according to this embodiment may further contain a filler such as an inorganic filler. Examples of fillers include those added to suppress thermal expansion and enhance flame retardancy of the cured resin composition, and are not particularly limited. Furthermore, the inclusion of a filler can further enhance heat resistance and flame retardancy. Specific examples of fillers include silica such as spherical silica, metal oxides such as alumina, titanium oxide, and mica, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, talc, aluminum borate, barium sulfate, and calcium carbonate. Among these, silica, mica, and talc are preferred, with spherical silica being more preferred. One type of filler may be used alone, or two or more types may be used in combination. The filler may be used as is, or may be surface-treated with the silane coupling agent.

[0104] It is also preferable to use silica as the inorganic filler, in which the ratio of the number of Si atoms contained in silanol groups to the total number of Si atoms is 3% or less. By incorporating silica with a low silanol group content as an inorganic filler into the resin composition of this embodiment, it is believed that a cured resin composition can be obtained that can more appropriately maintain low dielectric properties even after heat treatment. The silica has a ratio of the number of Si atoms contained in silanol groups to the total number of Si atoms of 3% or less, preferably 2.5% or less, and more preferably 2% or less. While a lower ratio is preferable, in practice, the limit is approximately 0.1%. For this reason, the ratio is preferably 0.1 to 3%.

[0105] The measurement of the ratio of the number of Si atoms contained in silanol groups to the total number of Si atoms in silica is not particularly limited as long as it is possible to measure the ratio of the number of Si atoms contained in silanol groups (Si-OH) contained in silica to the total number of Si atoms contained in silica. 29 This can be measured by obtaining a silica spectrum using Si-NMR measurement.

[0106] (Modified polyphenylene ether compound) The resin composition preferably further contains a modified polyphenylene ether compound terminally modified with a substituent having a carbon-carbon unsaturated double bond. The modified polyphenylene ether compound is not particularly limited as long as it is a modified polyphenylene ether compound terminally modified with a substituent having a carbon-carbon unsaturated double bond.

[0107] The substituent having a carbon-carbon unsaturated double bond is not particularly limited, and examples thereof include a substituent represented by the following formula (15) and a substituent represented by the following formula (16).

[0108] [ka]

[0109] In formula (15), p represents an integer of 0 to 10. A represents an arylene group. 12 ~R 14 are independent of each other. That is, R 12 ~R 14 may be the same group or different groups. 12 ~R 14 represents a hydrogen atom or an alkyl group.

[0110] In addition, in the formula (15), when p is 0, Z A is directly bonded to the end of the polyphenylene ether.

[0111] The arylene group is not particularly limited. Examples of the arylene group include monocyclic aromatic groups such as a phenylene group, and polycyclic aromatic groups in which the aromatic ring is not monocyclic but is polycyclic, such as a naphthalene ring. The arylene group also includes derivatives in which a hydrogen atom bonded to the aromatic ring is substituted with a functional group such as an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. The alkyl group is not particularly limited, and is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0112] [ka]

[0113] In formula (16), R 15 represents a hydrogen atom or an alkyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0114] Preferred specific examples of the substituent represented by the formula (15) include, for example, a substituent containing a vinylbenzyl group. Examples of the substituent containing a vinylbenzyl group include, for example, a substituent represented by the following formula (17). Furthermore, examples of the substituent represented by the formula (16) include, for example, an acrylate group and a methacrylate group.

[0115] [ka]

[0116] More specific examples of the substituent include vinylbenzyl groups (ethenylbenzyl groups) such as p-ethenylbenzyl and m-ethenylbenzyl groups, vinylphenyl groups, acrylate groups, and methacrylate groups.

[0117] The modified polyphenylene ether compound has a polyphenylene ether chain in the molecule, and preferably has, for example, a repeating unit represented by the following formula (18) in the molecule.

[0118] [ka]

[0119] In formula (18), t represents 1 to 50. 16 ~R 19 are independent of each other. That is, R 16 ~R 19 may be the same group or different groups. 16 ~R 19 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0120] R 16 ~R 19Specific examples of the functional groups mentioned in the above include the following:

[0121] The alkyl group is not particularly limited, but is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0122] The alkenyl group is not particularly limited, but is preferably an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples include a vinyl group, an allyl group, and a 3-butenyl group.

[0123] The alkynyl group is not particularly limited, but is preferably an alkynyl group having 2 to 18 carbon atoms, and more preferably an alkynyl group having 2 to 10 carbon atoms. Specific examples include an ethynyl group and a prop-2-yn-1-yl group (propargyl group).

[0124] The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, but for example, an alkylcarbonyl group having 2 to 18 carbon atoms is preferred, and an alkylcarbonyl group having 2 to 10 carbon atoms is more preferred. Specific examples include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pivaloyl group, a hexanoyl group, an octanoyl group, and a cyclohexylcarbonyl group.

[0125] The alkenylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkenyl group, but for example, an alkenylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkenylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include an acryloyl group, a methacryloyl group, and a crotonoyl group.

[0126] The alkynylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkynyl group, but for example, an alkynylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkynylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include a propioloyl group.

[0127] The weight-average molecular weight (Mw) of the modified polyphenylene ether compound is not particularly limited. Specifically, it is preferably 500 to 5,000, more preferably 800 to 4,000, and even more preferably 1,000 to 3,000. The weight-average molecular weight may be measured by a general molecular weight measurement method, specifically, a value measured using gel permeation chromatography (GPC), etc. Furthermore, when the modified polyphenylene ether compound has a repeating unit represented by the formula (18) in the molecule, t is preferably a numerical value such that the weight-average molecular weight of the modified polyphenylene ether compound falls within this range. Specifically, t is preferably 1 to 50.

[0128] When the weight-average molecular weight of the modified polyphenylene ether compound is within this range, the compound has the excellent low dielectric properties of polyphenylene ether, and the cured product not only has excellent heat resistance but also has excellent moldability. This is believed to be due to the following reasons. When the weight-average molecular weight of a normal polyphenylene ether is within this range, the compound has a relatively low molecular weight, which tends to reduce the heat resistance of the cured product. In contrast, the modified polyphenylene ether compound according to this embodiment has at least one unsaturated double bond at its terminal, which is believed to result in a cured product with sufficiently high heat resistance. Furthermore, when the weight-average molecular weight of the modified polyphenylene ether compound is within this range, the compound has a relatively low molecular weight, which is believed to result in excellent moldability. Therefore, it is believed that such a modified polyphenylene ether compound not only has excellent heat resistance but also has excellent moldability.

[0129] The average number of the substituents (number of terminal functional groups) at the molecular terminals per molecule of the modified polyphenylene ether compound is not particularly limited. Specifically, it is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.5 to 3. If the number of terminal functional groups is too small, it tends to be difficult to obtain a cured product with sufficient heat resistance. On the other hand, if the number of terminal functional groups is too large, the reactivity becomes too high, which may cause problems such as reduced shelf life and reduced fluidity of the resin composition. That is, when such a modified polyphenylene ether compound is used, insufficient fluidity may cause molding defects such as the generation of voids during multilayer molding, which may lead to moldability problems such as difficulty in obtaining a highly reliable printed wiring board.

[0130] The number of terminal functional groups in a modified polyphenylene ether compound may be, for example, a numerical value representing the average number of the above-mentioned substituents per molecule of all modified polyphenylene ether compounds present in 1 mole of the modified polyphenylene ether compound. The number of terminal functional groups can be measured, for example, by measuring the number of hydroxyl groups remaining in the obtained modified polyphenylene ether compound and calculating the difference from the number of hydroxyl groups in the polyphenylene ether before modification. This difference from the number of hydroxyl groups in the polyphenylene ether before modification is the number of terminal functional groups. The number of hydroxyl groups remaining in the modified polyphenylene ether compound can be measured by adding a quaternary ammonium salt (tetraethylammonium hydroxide) that associates with hydroxyl groups to a solution of the modified polyphenylene ether compound and measuring the UV absorbance of the resulting mixed solution.

[0131] The intrinsic viscosity of the modified polyphenylene ether compound is not particularly limited. Specifically, it may be 0.03 to 0.12 dL / g, preferably 0.04 to 0.11 dL / g, and more preferably 0.06 to 0.095 dL / g. If the intrinsic viscosity is too low, the molecular weight tends to be low, and it tends to be difficult to achieve low dielectric properties such as a low dielectric constant and a low dielectric loss tangent. On the other hand, if the intrinsic viscosity is too high, the viscosity tends to be high, sufficient fluidity cannot be obtained, and the moldability of the cured product tends to be reduced. Therefore, if the intrinsic viscosity of the modified polyphenylene ether compound is within the above range, excellent heat resistance and moldability of the cured product can be achieved.

[0132] The intrinsic viscosity here is the intrinsic viscosity measured in methylene chloride at 25°C, and more specifically, it is the value measured, for example, with a viscometer using a 0.18 g / 45 ml methylene chloride solution (liquid temperature: 25°C). Examples of such viscometers include the AVS500 Visco System manufactured by Schott.

[0133] Examples of the modified polyphenylene ether compound include a modified polyphenylene ether compound represented by the following formula (19) and a modified polyphenylene ether compound represented by the following formula (20). As the modified polyphenylene ether compound, these modified polyphenylene ether compounds may be used alone, or these two types of modified polyphenylene ether compounds may be used in combination.

[0134] [ka]

[0135] [ka]

[0136] In formula (19) and formula (20), R 20 ~R 27 and R 28 ~R 35each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. X1 and X2 each independently represent a substituent having a carbon-carbon unsaturated double bond. A and B represent repeating units represented by the following formula (21) and formula (22), respectively. In addition, in formula (20), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms.

[0137] [ka]

[0138] [ka]

[0139] In the formulas (21) and (22), m and n each represent an integer of 0 to 20. 36 ~R 39 and R 40 ~R 43 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0140] The modified polyphenylene ether compound represented by the formula (19) and the modified polyphenylene ether compound represented by the formula (20) are not particularly limited as long as they satisfy the above-mentioned constitution. Specifically, in the formulas (19) and (20), R 20 ~R 27 and R 28 ~R 35 are independent of each other, as mentioned above. That is, R 20 ~R 27 and R 28 ~R 35 may be the same group or different groups. 20 ~R 27 and R 28 ~R 35represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0141] In the formulas (21) and (22), m and n each preferably represent a value of 0 to 20, as described above. Furthermore, it is preferable that m and n represent a numerical value such that the sum of m and n is 1 to 30. Therefore, it is more preferable that m represents a numerical value of 0 to 20, n represents a numerical value of 0 to 20, and the sum of m and n represents a numerical value of 1 to 30. Furthermore, R 36 ~R 39 and R 40 ~R 43 are independent of each other. That is, R 36 ~R 39 and R 40 ~R 43 may be the same group or different groups. 36 ~R 39 and R 40 ~R 43 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0142] R 20 ~R 43 is R in the above formula (18). 16 ~R 19 is the same as

[0143] In the formula (20), Y is, as described above, a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms. Examples of Y include a group represented by the following formula (23).

[0144] [ka]

[0145] In the formula (23), R 44and R 45 are each independently a hydrogen atom or an alkyl group. Examples of the alkyl group include a methyl group. Examples of the group represented by formula (23) include a methylene group, a methylmethylene group, and a dimethylmethylene group, and among these, a dimethylmethylene group is preferred.

[0146] In the formula (19) and the formula (20), X1 and X2 are each independently a substituent having a carbon-carbon unsaturated double bond. The substituents X1 and X2 are not particularly limited as long as they are substituents having a carbon-carbon unsaturated double bond. Examples of the substituents X1 and X2 include the substituents represented by the formula (16) and the substituents represented by the formula (17). In the modified polyphenylene ether compound represented by the formula (19) and the modified polyphenylene ether compound represented by the formula (20), X1 and X2 may be the same or different substituents.

[0147] More specific examples of the modified polyphenylene ether compound represented by the formula (19) include modified polyphenylene ether compounds represented by the following formula (24).

[0148] [ka]

[0149] More specific examples of the modified polyphenylene ether compound represented by the formula (20) include a modified polyphenylene ether compound represented by the following formula (25) and a modified polyphenylene ether compound represented by the following formula (26).

[0150] [ka]

[0151] [ka]

[0152] In the above formulas (24) to (26), m and n have the same meaning as m and n in the above formulas (21) and (22), and are independently 0 to 20. In addition, in the above formulas (24) and (25), R 12 ~R 14 , p and Z A is R in the above formula (15). 12 ~R 14 , p and Z A In the above formulas (25) and (26), Y is the same as Y in the above formula (20). In the above formula (26), R 15 is R in the above formula (16). 15 is the same as

[0153] The method for synthesizing the modified polyphenylene ether compound used in the present embodiment is not particularly limited as long as it can synthesize a modified polyphenylene ether compound whose terminals are modified with a substituent having a carbon-carbon unsaturated double bond. Specific examples include a method of reacting polyphenylene ether with a compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded.

[0154] Examples of compounds in which a substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom include compounds in which a substituent represented by the formulas (15) to (17) is bonded to a halogen atom. Specific examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom, with a chlorine atom being preferred. More specific examples of compounds in which a substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom include p-chloromethylstyrene and m-chloromethylstyrene.

[0155] The polyphenylene ether used as the raw material is not particularly limited as long as it can ultimately synthesize a predetermined modified polyphenylene ether compound. Specific examples include polyphenylene ethers composed of 2,6-dimethylphenol and at least one of a bifunctional phenol and a trifunctional phenol, and those containing polyphenylene ether as the main component, such as poly(2,6-dimethyl-1,4-phenylene oxide). Furthermore, a bifunctional phenol is a phenolic compound having two phenolic hydroxyl groups per molecule, such as tetramethylbisphenol A. Furthermore, a trifunctional phenol is a phenolic compound having three phenolic hydroxyl groups per molecule.

[0156] The modified polyphenylene ether compound can be synthesized by the method described above. Specifically, the polyphenylene ether described above and a compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded are dissolved in a solvent and stirred. By doing so, the polyphenylene ether reacts with the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, thereby obtaining the modified polyphenylene ether compound used in this embodiment.

[0157] The reaction is preferably carried out in the presence of an alkali metal hydroxide. It is believed that this allows the reaction to proceed smoothly. This is believed to be because the alkali metal hydroxide functions as a dehydrohalogenating agent, specifically, a dehydrochlorinating agent. That is, it is believed that the alkali metal hydroxide eliminates hydrogen halide from the phenol group of the polyphenylene ether and a compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and as a result, the substituent having a carbon-carbon unsaturated double bond is bonded to the oxygen atom of the phenol group in place of the hydrogen atom of the phenol group of the polyphenylene ether.

[0158] The alkali metal hydroxide is not particularly limited as long as it can act as a dehalogenating agent, and examples thereof include sodium hydroxide, etc. The alkali metal hydroxide is usually used in the form of an aqueous solution, specifically, an aqueous sodium hydroxide solution.

[0159] Reaction conditions such as reaction time and reaction temperature vary depending on the compound in which a substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom, and are not particularly limited as long as the conditions are such that the above-mentioned reaction proceeds favorably. Specifically, the reaction temperature is preferably room temperature to 100°C, more preferably 30 to 100°C. The reaction time is preferably 0.5 to 20 hours, more preferably 0.5 to 10 hours.

[0160] The solvent used in the reaction is not particularly limited as long as it can dissolve the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and does not inhibit the reaction between the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded. Specific examples include toluene.

[0161] The above reaction is preferably carried out in the presence of not only an alkali metal hydroxide but also a phase transfer catalyst. That is, the above reaction is preferably carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst. Doing so is believed to allow the reaction to proceed more smoothly. This is believed to be due to the following: A phase transfer catalyst has the function of incorporating an alkali metal hydroxide, is soluble in both a polar solvent phase such as water and a nonpolar solvent phase such as an organic solvent, and is capable of transferring between these phases. Specifically, when an aqueous solution of sodium hydroxide is used as the alkali metal hydroxide and an organic solvent such as toluene, which is incompatible with water, is used as the solvent, even if the aqueous solution of sodium hydroxide is added dropwise to the solvent being used for the reaction, the solvent and the aqueous solution of sodium hydroxide separate, and it is believed that the sodium hydroxide is unlikely to migrate to the solvent. In this case, it is believed that the aqueous solution of sodium hydroxide added as the alkali metal hydroxide is unlikely to contribute to promoting the reaction. On the other hand, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst, the alkali metal hydroxide is transferred to the solvent while being incorporated into the phase transfer catalyst, and the aqueous sodium hydroxide solution is thought to contribute more to promoting the reaction. Therefore, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst, the reaction is thought to proceed more smoothly.

[0162] The phase transfer catalyst is not particularly limited, but examples thereof include quaternary ammonium salts such as tetra-n-butylammonium bromide.

[0163] When the resin composition used in the present embodiment contains the modified polyphenylene ether compound, it preferably contains the modified polyphenylene ether compound obtained as described above.

[0164] (Each content) The content of the free radical compound is preferably 0.01 to 0.4 parts by mass, more preferably 0.05 to 0.3 parts by mass, and even more preferably 0.1 to 0.2 parts by mass, relative to 100 parts by mass of the total of the polymer and the curing agent in the resin composition. When the content of the free radical compound is within the above range, it is believed that a cured product having low dielectric properties and high heat resistance and capable of more favorably maintaining low dielectric properties even after heat treatment and / or water absorption treatment can be obtained, and a resin composition having excellent moldability can be more reliably obtained.

[0165] The content of the polymer is preferably 10 to 95 parts by mass, more preferably 15 to 90 parts by mass, and even more preferably 20 to 90 parts by mass, relative to 100 parts by mass of the resin component (organic component) in the resin composition. That is, the content of the modified polyphenylene ether compound is preferably 10 to 95% by mass relative to the components other than the inorganic filler in the resin composition.

[0166] As described above, the resin composition may contain the curing agent. When the resin composition contains the curing agent, the content of the curing agent is, for example, preferably 5 to 50 parts by mass, more preferably 10 to 50 parts by mass, per 100 parts by mass of the resin component (organic component) in the resin composition. Furthermore, the content of the curing agent is preferably 5 to 50 parts by mass, more preferably 10 to 50 parts by mass, per 100 parts by mass of the total of the polymer and the curing agent.

[0167] When the contents of the polymer and the curing agent are within the above ranges, the resin composition has excellent heat resistance in the cured product, which is thought to be because the curing reaction between the polymer and the curing agent proceeds smoothly.

[0168] When the resin composition further contains the modified polyphenylene ether compound, the polymer, the modified polyphenylene ether compound, and the curing agent are preferably contained in the following amounts.

[0169] The total content of the polymer and the modified polyphenylene ether compound is preferably 10 to 95 parts by mass, more preferably 15 to 90 parts by mass, and even more preferably 20 to 90 parts by mass, relative to 100 parts by mass of the resin component (organic component) in the resin composition. That is, the total content of the polymer and the modified polyphenylene ether compound is preferably 10 to 95% by mass, relative to the resin component (organic component) in the resin composition.

[0170] When the contents of the polymer and the modified polyphenylene ether compound are within the above ranges, a resin composition having excellent dielectric properties and moldability can be obtained.

[0171] When the resin composition of this embodiment contains the reaction initiator, its content is not particularly limited, but is preferably 0.5 to 8.0 parts by mass, more preferably 0.5 to 5.0 parts by mass, and even more preferably 0.5 to 2.0 parts by mass, per 100 parts by mass of the total mass of the polymer and the curing agent (and the modified polyphenylene ether compound). If the content of the reaction initiator is too low, the curing reaction between the polymer and the curing agent tends not to start properly. If the content of the initiator is too high, the dielectric loss tangent of the obtained cured prepreg tends to increase, making it difficult to exhibit excellent low dielectric properties. Therefore, if the content of the reaction initiator is within the above range, a cured prepreg with excellent low dielectric properties can be obtained.

[0172] When the resin composition of this embodiment contains the reaction initiator, the ratio (mass ratio) of the free radical compound to the reaction initiator in the resin composition (free radical compound: reaction initiator) is preferably about 0.005:1 to 0.2:1.0, more preferably about 0.01:1.0 to 0.2:1.0, and even more preferably about 0.1:1.0 to 0.2:1.0. It is believed that this allows the effects of the present invention to be obtained more reliably.

[0173] Furthermore, when the resin composition of the present embodiment contains an inorganic filler, the content thereof (filler content) is preferably 30 to 270 mass %, and more preferably 50 to 250 mass %, relative to the resin composition.

[0174] (Other ingredients) The resin composition according to the present embodiment may contain other components (other components) in addition to the components described above, as necessary, as long as the effects of the present invention are not impaired. Examples of other components contained in the resin composition according to the present embodiment include additives such as a reaction accelerator, a catalyst, a dispersant, a leveling agent, a silane coupling agent, a flame retardant, an antifoaming agent, an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a dye or pigment, and a lubricant. Furthermore, in addition to the modified polyphenylene ether compound, the curing agent, and the polymer, the resin composition may also contain a thermosetting resin such as polyphenylene ether or an epoxy resin.

[0175] As described above, the resin composition according to this embodiment may contain a flame retardant. The inclusion of a flame retardant can enhance the flame retardancy of the cured resin composition. The flame retardant is not particularly limited. Specifically, in fields where halogen-based flame retardants such as bromine-based flame retardants are used, for example, ethylene dipentabromobenzene, ethylene bistetrabromoimide, decabromodiphenyl oxide, and tetradecabromodiphenoxybenzene, which have melting points of 300°C or higher, are preferred. The use of halogen-based flame retardants is believed to suppress halogen elimination at high temperatures and prevent a decrease in heat resistance. Furthermore, in fields where halogen-free materials are required, phosphorus-containing flame retardants may be used. Specific examples include phosphate ester-based flame retardants, phosphazene-based flame retardants, bisdiphenylphosphine oxide-based flame retardants, and phosphinate-based flame retardants. Specific examples of phosphate ester-based flame retardants include condensed phosphate esters of dixylenyl phosphate. Specific examples of phosphazene-based flame retardants include phenoxyphosphazene. A specific example of a bisdiphenylphosphine oxide flame retardant is xylylenebisdiphenylphosphine oxide. A specific example of a phosphinate flame retardant is a metal phosphinate of an aluminum dialkylphosphinate. As the flame retardant, each of the exemplified flame retardants may be used alone or in combination of two or more.

[0176] (Manufacturing method) The method for producing the resin composition is not particularly limited, and examples thereof include a method of mixing the polymer and the free radical compound with other components as necessary, etc. Specifically, in the case of obtaining a varnish-like composition containing an organic solvent, the method described in the description of the prepreg below can be used.

[0177] In the resin composition of this embodiment, the minimum melt viscosity (T2) and the melt viscosity (T1) at a temperature 10°C above the minimum melt viscosity temperature are preferably such that T1 / T2 is 5.0 or less. This is believed to have the advantage of further improving moldability. More preferably, the ratio is greater than 1.0 and 2.0 or less.

[0178] Furthermore, it is preferable that T2 is 14,000 (poise) or less and T1 is 15,000 (poise) or less. This is because it is thought that the resin composition can be easily filled into the pattern and moldability can be improved. Furthermore, it is particularly preferable that T2 is 8,000 (poise) or less and T1 is 10,000 (poise) or less.

[0179] Furthermore, the resin composition of this embodiment preferably has a dielectric loss tangent (10 GHz) of 0.0024 or less, and more preferably 0.0020 or less, in a cured product thereof.

[0180] Furthermore, when a cured product of the resin composition of this embodiment is subjected to moisture absorption treatment (treatment for 120 hours in an environment of a temperature of 85°C and a humidity of 85%) according to JIS C 6481 (1996) and the difference in dielectric tangent between the cured product before and after the treatment is measured, it is preferable that the (dielectric tangent after moisture absorption treatment) - (dielectric tangent before moisture absorption treatment) is 0.0010 or less, more preferably 0.0009 or less, and even more preferably 0.0006 or less.

[0181] Furthermore, when a cured product of the resin composition of this embodiment is held (heat-treated) at 130°C for 120 hours and the difference between the dielectric loss tangent of the heat-treated cured product (dielectric loss tangent after heat treatment) and the dielectric loss tangent of the cured product before heat treatment is measured, it is preferable that (dielectric loss tangent after heat treatment) - (dielectric loss tangent before heat treatment) is 0.0012 or less, and more preferably 0.0010 or less.

[0182] Furthermore, by using the resin composition according to this embodiment, it is possible to obtain a prepreg, a metal-clad laminate, a wiring board, a resin-coated metal foil, and a resin-coated film as follows: In the following description, the respective reference numerals represent: 1 prepreg, 2 resin composition or semi-cured resin composition, 3 fibrous substrate, 11 metal-clad laminate, 12 insulating layer, 13 metal foil, 14 wiring, 21 wiring board, 31 resin-coated metal foil, 32 and 42 resin layer, 41 resin-coated film, and 43 support film.

[0183] [Prepreg] FIG. 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention.

[0184] 1, the prepreg 1 according to this embodiment comprises the resin composition or a semi-cured product of the resin composition 2, and a fibrous base material 3. This prepreg 1 comprises the resin composition or a semi-cured product of the resin composition 2, and the fibrous base material 3 present in the resin composition or the semi-cured product of the resin composition 2.

[0185] In this embodiment, the semi-cured product refers to a resin composition that has been partially cured to the extent that it can be further cured. That is, the semi-cured product refers to a resin composition that has been semi-cured (B-staged). For example, when a resin composition is heated, the viscosity initially gradually decreases, then curing begins, and then curing begins and the viscosity gradually increases. In such a case, the semi-cured state can be exemplified by the state between when the viscosity begins to increase and when the composition is completely cured.

[0186] Furthermore, the prepreg obtained using the resin composition according to this embodiment may comprise a semi-cured product of the resin composition as described above, or may comprise the uncured resin composition itself. That is, it may be a prepreg comprising a semi-cured product of the resin composition (the resin composition in B stage) and a fibrous base material, or a prepreg comprising the resin composition before curing (the resin composition in A stage) and a fibrous base material. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried.

[0187] When producing a prepreg, the resin composition 2 is often prepared in a varnish form and used to impregnate the fibrous base material 3, which is the base material for forming the prepreg. That is, the resin composition 2 is usually often a resin varnish prepared in a varnish form. Such a varnish-like resin composition (resin varnish) is prepared, for example, as follows.

[0188] First, each component of the resin composition that is soluble in an organic solvent is added to the organic solvent and dissolved. Heating may be performed if necessary. Subsequently, components that are insoluble in the organic solvent (e.g., inorganic fillers) are added as needed, and the mixture is dispersed using a ball mill, bead mill, planetary mixer, roll mill, or the like until a predetermined dispersion state is achieved, thereby preparing a varnish-like resin composition. The organic solvent used here is not particularly limited, as long as it dissolves the modified polyphenylene ether compound, the curing agent, and the like and does not inhibit the curing reaction. Specific examples include toluene and methyl ethyl ketone (MEK).

[0189] The method for producing the prepreg is not particularly limited as long as it can produce the prepreg. Specifically, when producing the prepreg, the resin composition used in the present embodiment is often prepared in the form of a varnish as described above and used as a resin varnish.

[0190] Specific examples of the fibrous substrate include glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. The use of glass cloth provides a laminate with excellent mechanical strength, and flattened glass cloth is particularly preferred. A specific example of the flattening process is a method in which glass cloth is continuously pressed with a press roll at an appropriate pressure to compress the yarns flat. The thickness of commonly used fibrous substrates is, for example, 0.01 mm or more and 0.3 mm or less.

[0191] The method for producing the prepreg is not particularly limited as long as it can produce the prepreg. Specifically, when producing the prepreg, the resin composition according to the present embodiment is often prepared in the form of a varnish as described above and used as a resin varnish.

[0192] The prepreg 1 can be produced, for example, by impregnating a fibrous substrate 3 with a resin composition 2, for example, a resin composition 2 prepared in the form of a varnish, followed by drying. The resin composition 2 is impregnated into the fibrous substrate 3 by immersion, coating, or the like. Impregnation can be repeated multiple times as necessary. In this case, by repeating the impregnation using multiple resin compositions with different compositions and concentrations, it is possible to adjust the final composition and impregnation amount to the desired one.

[0193] The fibrous substrate 3 impregnated with the resin composition (resin varnish) 2 is heated under desired conditions, for example, at 80°C to 180°C for 1 minute to 10 minutes. The heating produces a prepreg 1 in an uncured (A-stage) or semi-cured (B-stage) state. The heating also volatilizes the organic solvent from the resin varnish, reducing or eliminating the organic solvent.

[0194] The resin composition according to this embodiment or a prepreg comprising a semi-cured product of this resin composition is a prepreg that can be suitably used to obtain a cured product that has low dielectric properties and high heat resistance, and that can favorably maintain its low dielectric properties even after heat treatment or water absorption treatment. Furthermore, it has good moldability and, when used in wiring boards, etc., also has excellent filling properties into circuit patterns.

[0195] [Metal-clad laminate] FIG. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate 11 according to an embodiment of the present invention.

[0196] As shown in FIG. 2, the metal-clad laminate 11 is composed of an insulating layer 12 containing a cured product of the prepreg 1 shown in FIG. 1 and a metal foil 13 laminated together with the insulating layer 12. That is, the metal-clad laminate 11 has an insulating layer 12 containing a cured product of a resin composition and a metal foil 13 provided on the insulating layer 12. The insulating layer 12 may be made of a cured product of the resin composition or a cured product of the prepreg. The thickness of the metal foil 13 varies depending on the performance required of the final wiring board and is not particularly limited. The thickness of the metal foil 13 can be appropriately set depending on the desired purpose and is preferably, for example, 0.2 to 70 μm. Examples of the metal foil 13 include copper foil and aluminum foil. When the metal foil is thin, it may be a carrier-supported copper foil having a release layer and a carrier to improve handleability.

[0197] The method for producing the metal-clad laminate 11 is not particularly limited as long as it can produce the metal-clad laminate 11. Specifically, a method for producing the metal-clad laminate 11 using a prepreg 1 can be used. Examples of such a method include a method in which one or more prepregs 1 are stacked, and then a metal foil 13 such as copper foil is stacked on both or one of the upper and lower surfaces of the prepreg 1, and the metal foil 13 and the prepreg 1 are heated and pressurized to form an integrated laminate, thereby producing a double-sided or single-sided metal foil-clad laminate 11. That is, the metal-clad laminate 11 is obtained by stacking the metal foil 13 on the prepreg 1 and then heating and pressurizing the resulting laminate. The heating and pressurizing conditions can be appropriately set depending on the thickness of the metal-clad laminate 11 to be produced, the type of composition of the prepreg 1, and other factors. For example, the temperature can be 170 to 210°C, the pressure can be 3.5 to 4 MPa, and the time can be 60 to 150 minutes. The metal-clad laminate may also be produced without using a prepreg. For example, a method may be used in which a varnish-like resin composition is applied onto a metal foil to form a layer containing the resin composition on the metal foil, and then the layer is heated and pressed.

[0198] The metal-clad laminate having an insulating layer containing a cured product of the resin composition according to the present embodiment is a metal-clad laminate having an insulating layer that has low dielectric properties, high heat resistance, and can favorably maintain its low dielectric properties even after heat treatment or water absorption treatment. Furthermore, it has good formability and, when used in a wiring board or the like, has excellent filling ability into a circuit pattern.

[0199] [Wiring board] FIG. 3 is a schematic cross-sectional view showing an example of wiring board 21 according to an embodiment of the present invention.

[0200] As shown in Fig. 3, wiring board 21 according to this embodiment is composed of insulating layer 12, which is formed by curing prepreg 1 shown in Fig. 1, and wiring 14, which is laminated together with insulating layer 12 and formed by partially removing metal foil 13. That is, wiring board 21 has insulating layer 12 containing a cured product of a resin composition, and wiring 14 provided on insulating layer 12. Furthermore, insulating layer 12 may be made of a cured product of the resin composition, or may be made of a cured product of the prepreg.

[0201] The method for manufacturing the wiring board 21 is not particularly limited as long as it can produce the wiring board 21. Specifically, a method for manufacturing the wiring board 21 using the prepreg 1 can be used. Examples of such a method include a method for manufacturing the wiring board 21 by etching the metal foil 13 on the surface of the metal-clad laminate 11 manufactured as described above to form wiring, thereby manufacturing the wiring board 21 having wiring provided as a circuit on the surface of the insulating layer 12. That is, the wiring board 21 can be obtained by forming a circuit by partially removing the metal foil 13 on the surface of the metal-clad laminate 11. In addition to the above methods, other methods for forming a circuit include circuit formation by a semi-additive process (SAP) or a modified semi-additive process (MSAP). The wiring board 21 has an insulating layer 12 that has low dielectric properties and high heat resistance and can favorably maintain its low dielectric properties even after a water absorption treatment.

[0202] Such a wiring board is a wiring board having an insulating layer with low dielectric properties and high heat resistance, and capable of favorably maintaining its low dielectric properties even after heat treatment or water absorption treatment. Furthermore, the resin composition of this embodiment has good moldability and exhibits good filling properties even in circuit patterns on wiring boards. Therefore, it has the advantage of being usable in wiring boards in which the distance between conductor circuits (wiring) is narrow. The resin composition of this embodiment is not particularly limited, but can also be suitably used in wiring boards in which a conductor circuit pattern is provided in which the distance between conductor circuits is at least partially, for example, 50 μm or less.

[0203] In particular, the wiring board of this embodiment may be a multilayer wiring board having two or more circuit layers, and the resin composition of this embodiment can be suitably used as an interlayer insulating material for the multilayer wiring board. Although not particularly limited, the wiring board may be, for example, a multilayer wiring board having two or more circuit layers and a wiring pattern in which the distance between the wirings is 50 μm or less in at least a portion thereof. Furthermore, for example, a wiring pattern in which the distance between the wirings is 30 μm or less in at least a portion thereof may be provided.

[0204] Furthermore, the resin composition of this embodiment is preferably used as an insulating material for the insulating layer of a highly multilayer wiring board having five or more circuit layers, or even ten or more circuit layers, although this is not particularly limited. In the manufacture of a highly multilayer wiring board having five or more circuit layers, or even ten or more circuit layers, the interlayer insulating material of this embodiment can be used to stably embed each inner layer circuit in the multilayering process of forming each interlayer insulating layer, ensuring excellent moldability. By ensuring excellent moldability, separation at the adhesive surface between the inner layer circuit of the multilayer wiring board and the interlayer insulating layer can be prevented when a highly multilayer wiring board having five or more circuit layers, or even ten or more circuit layers, is subjected to high-temperature treatment after absorbing moisture, for example.

[0205] [Metal foil with resin] FIG. 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil 31 according to this embodiment.

[0206] 4, the resin-coated metal foil 31 according to this embodiment comprises a resin layer 32 containing the resin composition or a semi-cured product of the resin composition, and a metal foil 13. The resin-coated metal foil 31 has the metal foil 13 on the surface of the resin layer 32. That is, the resin-coated metal foil 31 comprises the resin layer 32 and the metal foil 13 laminated together with the resin layer 32. The resin-coated metal foil 31 may also comprise another layer between the resin layer 32 and the metal foil 13.

[0207] The resin layer 32 may contain a semi-cured product of the resin composition as described above, or may contain the uncured resin composition. That is, the resin-coated metal foil 31 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition in B stage) and a metal foil, or a resin layer containing the resin composition before curing (the resin composition in A stage) and a metal foil. The resin layer may contain the resin composition or a semi-cured product of the resin composition, but may or may not contain a fibrous substrate. The resin composition or the semi-cured product of the resin composition may be obtained by drying or heat-drying the resin composition. The fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0208] The metal foil may be any metal foil used in metal-clad laminates, including, for example, copper foil and aluminum foil.

[0209] The resin-coated metal foil 31 and the resin-coated film 41 may be provided with a cover film or the like, as necessary. By providing a cover film, it is possible to prevent the inclusion of foreign matter, etc. The cover film is not particularly limited, but examples thereof include polyolefin film, polyester film, polymethylpentene film, and films formed by providing a release agent layer on these films.

[0210] The method for producing the resin-coated metal foil 31 is not particularly limited as long as it can produce the resin-coated metal foil 31. Examples of methods for producing the resin-coated metal foil 31 include a method of applying the varnish-like resin composition (resin varnish) onto the metal foil 13 and heating it. The varnish-like resin composition is applied onto the metal foil 13, for example, using a bar coater. The applied resin composition is heated, for example, at 80°C or higher and 180°C or lower, for 1 minute or longer and 10 minutes or shorter. The heated resin composition is formed on the metal foil 13 as an uncured resin layer 32. Note that the heating volatilizes the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0211] The resin-coated metal foil having a resin layer containing the resin composition according to this embodiment or a semi-cured product of this resin composition is a resin-coated metal foil that can be used to obtain a cured product that has low dielectric properties and high heat resistance and can maintain its low dielectric properties even after heat treatment or water absorption treatment. Furthermore, it has good formability and, when used in wiring boards, etc., has excellent filling properties into circuit patterns. For example, by laminating it on a wiring board, a multilayer wiring board can be produced.

[0212] [Resin-coated film] FIG. 5 is a schematic cross-sectional view showing an example of a resin-coated film 41 according to the present embodiment.

[0213] 5, the resin-coated film 41 according to this embodiment includes a resin layer 42 containing the resin composition or a semi-cured product of the resin composition, and a support film 43. The resin-coated film 41 includes the resin layer 42 and the support film 43 laminated together with the resin layer 42. The resin-coated film 41 may also include another layer between the resin layer 42 and the support film 43.

[0214] The resin layer 42 may contain a semi-cured product of the resin composition as described above, or may contain the uncured resin composition. That is, the resin-coated film 41 may include a resin layer containing a semi-cured product of the resin composition (the resin composition in B stage) and a support film, or may be a resin-coated film including a resin layer containing the resin composition before curing (the resin composition in A stage) and a support film. The resin layer may contain the resin composition or a semi-cured product of the resin composition, and may or may not contain a fibrous substrate. The resin composition or the semi-cured product of the resin composition may be obtained by drying or heat-drying the resin composition. The fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0215] Furthermore, any support film used for a resin-coated film can be used without limitation as the support film 43. Examples of the support film include electrically insulating films such as polyester film, polyethylene terephthalate (PET) film, polyimide film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, polyamide film, polycarbonate film, and polyarylate film.

[0216] The resin-coated film 41 may be provided with a cover film or the like as needed. By providing a cover film, it is possible to prevent the inclusion of foreign matter, etc. The cover film is not particularly limited, but examples thereof include a polyolefin film, a polyester film, and a polymethylpentene film.

[0217] The support film and cover film may be subjected to surface treatment such as matte treatment, corona treatment, release treatment, and roughening treatment, if necessary.

[0218] The method for producing the resin-coated film 41 is not particularly limited as long as it can produce the resin-coated film 41. Examples of methods for producing the resin-coated film 41 include a method in which the varnish-like resin composition (resin varnish) is applied to a support film 43 and heated. The varnish-like resin composition is applied to the support film 43 using, for example, a bar coater. The applied resin composition is heated, for example, at a temperature of 80°C to 180°C for 1 minute to 10 minutes. The heated resin composition is formed on the support film 43 as an uncured resin layer 42. The heating volatilizes the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0219] A resin-coated film having a resin layer containing the resin composition according to this embodiment or a semi-cured product of this resin composition is a resin-coated film that can be used to obtain a cured product that has low dielectric properties and high heat resistance and can favorably maintain its low dielectric properties even after heat treatment or water absorption treatment. Furthermore, it has good formability and, when used in wiring boards, etc., has excellent filling properties into circuit patterns. For example, a multilayer wiring board can be produced by laminating the resin composition on a wiring board and then peeling off the support film, or by laminating the resin composition on a wiring board after peeling off the support film.

[0220] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples. [Example]

[0221] [Examples 1 to 15 and Comparative Examples 1 to 5] In this example, each component used in preparing the resin composition will be described.

[0222] (resin component) Polymer 1: 2.9 moles (377 g) of divinylbenzene, 1.7 moles (224.4 g) of ethylvinylbenzene, 10.4 moles (1081.6 g) of styrene, and 15 moles (1532 g) of n-propyl acetate were placed in a 5.0 L reactor, and 600 mmol of boron trifluoride diethyl ether complex was added at 70°C. The reaction was carried out for 4 hours. The polymerization solution was stopped with an aqueous sodium bicarbonate solution, and the oil layer was washed three times with pure water. The volatiles were removed under reduced pressure at 60°C, and Polymer 1 was recovered.

[0223] Polymer 1, which has a structural unit represented by the formula (1) in its molecule, is an aromatic polymer having structural units derived from a bifunctional aromatic compound in which two carbon-carbon unsaturated double bonds are bonded to an aromatic ring, and is a compound having structural units represented by the formulas (12) to (14). The weight-average molecular weight Mw is 26,300. The equivalent weight (vinyl equivalent) of the vinyl group contained in the structural unit represented by the formula (1) in which R1 to R3 are hydrogen atoms is 510.

[0224] Polymer 2: 3.6 mol (468 g) of divinylbenzene, 2.2 mol (290.4 g) of ethylvinylbenzene, 9.2 mol (956.8 g) of styrene, and 15 mol (1532 g) of n-propyl acetate were placed in a 5.0 L reactor, and 600 mmol of boron trifluoride diethyl ether complex was added at 70°C. The reaction was carried out for 4 hours. The polymerization solution was stopped with an aqueous solution of sodium bicarbonate, and the oil layer was washed three times with pure water. The volatile components were removed under reduced pressure at 60°C, and copolymer 2 was recovered.

[0225] Polymer 2, which has a structural unit represented by formula (1) in its molecule, is an aromatic polymer having structural units derived from a bifunctional aromatic compound in which two carbon-carbon unsaturated double bonds are bonded to an aromatic ring, and is a compound having structural units represented by formulas (12) to (14). The weight-average molecular weight Mw is 31,100. The equivalent weight (vinyl equivalent) of the vinyl group contained in the structural unit represented by formula (1) in which R1 to R3 are hydrogen atoms is 380.

[0226] Polymer 3: 3.9 moles (507 g) of divinylbenzene, 2.3 moles (303.6 g) of ethylvinylbenzene, 8.8 moles (915.2 g) of styrene, and 15 moles (1532 g) of n-propyl acetate were placed in a 5.0 L reactor, and 600 mmol of boron trifluoride diethyl ether complex was added at 70°C. The reaction was carried out for 4 hours. The polymerization solution was stopped with an aqueous sodium bicarbonate solution, and the oil layer was washed three times with pure water. The volatiles were removed under reduced pressure at 60°C, and copolymer 3 was recovered.

[0227] Polymer 3 is a polymer having a structural unit represented by the formula (1) in the molecule: an aromatic polymer having a structural unit derived from a bifunctional aromatic compound in which two carbon-carbon unsaturated double bonds are bonded to an aromatic ring, and is a compound having structural units represented by the formulas (12) to (14). The weight-average molecular weight Mw is 39,500. In addition, the equivalent weight (vinyl equivalent) of the vinyl group contained in the structural unit represented by the formula (1) in which R1 to R3 are hydrogen atoms is 320.

[0228] The vinyl equivalent weight (vinyl equivalent weight) of the vinyl group contained in the structural unit of polymers 1 to 3 represented by the formula (1) where R1 to R3 are hydrogen atoms was calculated by measuring the iodine value by the Wiess method. Specifically, the compound to be measured was first dissolved in chloroform to a concentration of 0.3 g / 30 mL. An excess amount of iodine chloride was added to the double bonds present in this solution. This caused the double bonds to react with iodine chloride. After this reaction had progressed sufficiently, a 20% by mass aqueous solution of potassium iodide was added to the solution after the reaction, and the iodine remaining in the solution after the reaction was reduced to 13 - This I3 - The aqueous phase into which the extract was extracted was titrated with an aqueous sodium thiosulfate solution (0.1 mol / L sodium thiosulfate standard solution) to calculate the iodine value. The iodine value was calculated using the following formula.

[0229] Iodine value = [(BA) × F × 1.269] / mass of compound (g) In the above formula, B represents the titer (cc) of 0.1 mol / L sodium thiosulfate standard solution required for the blank test, A represents the titer (cc) of 0.1 mol / L sodium thiosulfate standard solution required for neutralization, and F represents the titer of sodium thiosulfate.

[0230] Modified PPE: Modified PPE obtained by reacting polyphenylene ether with chloromethylstyrene. Specifically, it is a modified PPE obtained by the following reaction:

[0231] First, 200 g of polyphenylene ether (SA90 manufactured by SABIC Innovative Plastics, 2 terminal hydroxyl groups, weight-average molecular weight Mw 1700), 30 g of a 50:50 mass ratio mixture of p-chloromethylstyrene and m-chloromethylstyrene (chloromethylstyrene: CMS manufactured by Tokyo Chemical Industry Co., Ltd.), 1.227 g of tetra-n-butylammonium bromide as a phase transfer catalyst, and 400 g of toluene were charged into a 1-liter three-neck flask equipped with a temperature controller, stirrer, cooling equipment, and dropping funnel, and the mixture was stirred. The mixture was then stirred until the polyphenylene ether, chloromethylstyrene, and tetra-n-butylammonium bromide were dissolved in the toluene. The mixture was gradually heated until the liquid temperature reached 75°C. An aqueous sodium hydroxide solution (20 g sodium hydroxide / 20 g water) was added dropwise to the solution as an alkali metal hydroxide over 20 minutes. The mixture was then stirred at 75°C for an additional 4 hours. Next, the contents of the flask were neutralized with 10% by mass of hydrochloric acid, and then a large amount of methanol was added. This caused a precipitate to form in the liquid in the flask. In other words, the product contained in the reaction solution in the flask was reprecipitated. This precipitate was then filtered, washed three times with a mixture of methanol and water in an 80:20 mass ratio, and then dried under reduced pressure at 80°C for 3 hours.

[0232] The obtained solid is 1The solid was analyzed by H-NMR (400 MHz, CDCl3, TMS). As a result of NMR measurement, a peak derived from a vinylbenzyl group (ethenylbenzyl group) was confirmed at 5 to 7 ppm. This confirmed that the obtained solid was a modified polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) as the substituent at the molecular end in the molecule. Specifically, it was confirmed that it was an ethenylbenzylated polyphenylene ether. The obtained modified polyphenylene ether compound is represented by the above formula (18), in which Y is a dimethylmethylene group (represented by formula (16), and R in formula (16) 33 and R 34 is a methyl group), Z is a phenylene group, R1 to R3 are hydrogen atoms, n is 1, and p is 1.

[0233] The number of terminal functional groups of the modified polyphenylene ether was measured as follows.

[0234] First, the modified polyphenylene ether was accurately weighed. The weight at that time was designated X (mg). Then, this weighed modified polyphenylene ether was dissolved in 25 mL of methylene chloride, and 100 μL of a 10 mass% ethanol solution of tetraethylammonium hydroxide (TEAH) (TEAH:ethanol (volume ratio) = 15:85) was added to the solution, and the absorbance (Abs) at 318 nm was measured using a UV spectrophotometer (UV-1600, manufactured by Shimadzu Corporation). Then, from the measurement results, the number of terminal hydroxyl groups of the modified polyphenylene ether was calculated using the following formula.

[0235] Residual OH amount (μmol / g) = [(25×Abs) / (ε×OPL×X)]×10 6 where ε is the extinction coefficient, 4700 L / mol cm, and OPL is the cell path length, 1 cm.

[0236] The calculated residual OH amount (number of terminal hydroxyl groups) of the modified polyphenylene ether was almost zero, which indicated that the hydroxyl groups of the polyphenylene ether before modification were almost entirely modified. This indicated that the decrease in the number of terminal hydroxyl groups from the polyphenylene ether before modification was the number of terminal hydroxyl groups of the polyphenylene ether before modification. In other words, it was found that the number of terminal hydroxyl groups of the polyphenylene ether before modification was the number of terminal functional groups of the modified polyphenylene ether. In other words, the number of terminal functional groups was two.

[0237] The intrinsic viscosity (IV) of the modified polyphenylene ether was measured in methylene chloride at 25°C. Specifically, the intrinsic viscosity (IV) of the modified polyphenylene ether was measured using a viscometer (AVS500 Visco System manufactured by Schott) for a 0.18 g / 45 ml methylene chloride solution (liquid temperature 25°C) of the modified polyphenylene ether. As a result, the intrinsic viscosity (IV) of the modified polyphenylene ether was 0.086 dL / g.

[0238] The molecular weight distribution of the modified polyphenylene ether was measured using GPC. The weight average molecular weight (Mw) was calculated from the molecular weight distribution obtained. As a result, Mw was 2,300.

[0239] (hardening agent) Acenaphthylene: Acenaphthylene manufactured by JFE Chemical Corporation Maleimide compound: N-phenylmonomaleimide manufactured by Nippon Shokubai Co., Ltd.

[0240] (Reaction initiator) Azo initiator: Fujifilm Wako Pure Chemical Industries, Ltd.'s "VR-110" Peroxide initiator: PBP (1,3-bis(butylperoxyisopropyl)benzene; Perbutyl P manufactured by NOF Corporation)

[0241] (free radical compounds) Free radical compound 1: A free radical compound represented by the following formula ("H0865" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0242] [ka]

[0243] Free radical compound 2: A free radical compound represented by the following formula ("T3751" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0244] [ka]

[0245] Free radical compound 3: A free radical compound represented by the following formula ("H0878" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0246] [ka]

[0247] Free radical compound 4: A free radical compound represented by the following formula ("B5642" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0248] [ka]

[0249] Free radical compound 5: A free radical compound represented by the following formula ("C1406" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0250] [ka]

[0251] Free radical compound 6: A free radical compound represented by the following formula ("D4313" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0252] [ka]

[0253] Free radical compound 7: A free radical compound represented by the following formula ("G0020" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0254] [ka]

[0255] (catechol compounds) 4-tert-Butylcatechol: 4-tert-Butylcatechol manufactured by Tokyo Chemical Industry Co., Ltd.

[0256] (Inorganic filler) Silica filler 1: Admatechs' "SC-2300SVJ" (silica with 4.0% silanol group content) Silica filler 2: "5SV-C" manufactured by Admatechs (silica with 1.0% silanol group content)

[0257] (Preparation method) First, the above components except for the inorganic filler were added to toluene and mixed in the composition (parts by mass) shown in Table 3 so that the solids concentration was 55% by mass. The mixture was stirred for 60 minutes. Thereafter, the inorganic filler was added to the resulting liquid, and the filler was dispersed using a bead mill. This resulted in a varnish-like resin composition (varnish).

[0258] [Melt viscosity] 0.5 g of the powdery, semi-cured resin composition obtained from the prepreg was pressed under a pressure of 2.8 MPa into a pellet with a diameter of 1.0 cm and a height of 0.5 cm to prepare a measurement sample. The melting behavior of the measurement sample was measured using a Rheosol G3000NT dynamic viscoelasticity measuring device. The measurement conditions involved raising the sample temperature at a rate of 4 degrees per minute, and measuring the viscosity (poise) of the sample during this period. The temperature at which the measured viscosity decreased the most during the temperature rise process from the semi-cured state (B stage) to the cured state (C stage) was determined as the minimum melt viscosity (T2).

[0259] [T1 / T2] The melt viscosity when the temperature was raised by 10°C from the minimum melt viscosity (T2) was defined as T1, and T1 / T2 was calculated. T1 / T2 is an index for measuring the curing speed from the state where T2 was reached once during the temperature rise (the state where the viscosity is at its lowest), and a smaller T1 / T2 value indicates a slower curing speed, which is considered to be one of the characteristics of a resin composition with high moldability.

[0260] Next, an evaluation substrate (cured prepreg) was obtained as follows.

[0261] The resulting varnish was impregnated into a fibrous substrate (glass cloth: Asahi Kasei Corporation's 1078L, #1078 type, L glass) and then heated and dried at 120°C for 3 minutes to produce a prepreg. The resin content of the components that make up the resin through the curing reaction was adjusted to 67% by mass. Two of the resulting prepregs were then stacked and heated and pressurized at 200°C for 2 hours at a pressure of 3 MPa to produce an evaluation substrate (cured prepreg).

[0262] Next, an evaluation substrate (metal-clad laminate) was obtained as follows.

[0263] A fibrous substrate (glass cloth: Asahi Kasei Corporation's GC1078L, #1078 type, L glass) was impregnated with the varnish and then heated and dried for 3 minutes at 120°C to produce a prepreg. The content of the components that make up the resin by the curing reaction (resin content) relative to the prepreg was adjusted to 67% by mass.

[0264] Two sheets of each prepreg were stacked on top of each other, and copper foil (FV-WS, 18 μm thick, manufactured by Furukawa Electric Co., Ltd.) was placed on both sides to form a pressure body. The body was heated and pressed at a temperature of 200°C and a pressure of 3 MPa for 2 hours to produce a copper foil-clad laminate, an evaluation substrate (metal-clad laminate) with copper foil bonded to both sides.

[0265] The evaluation substrates (cured prepreg and metal-clad laminate) prepared as described above were evaluated by the following methods.

[0266] [Moldability] A 200mm x 200mm cured product with a grid-like copper pattern, 80% copper residual, and 35μm line thickness, was prepared. A 200mm x 200mm prepreg was layered on top of this. A 250mm x 250mm copper foil with a thickness of 35μm was layered on top of this. These were sandwiched between metal plates approximately 3mm thick and heated and pressurized using a laminate molding press under the following conditions. The heating conditions were a rate of 4°C per minute from 30°C to 200°C. The pressure applied to the prepreg was set to 1MPa at the start of heating, and then, when the temperature reached 110°C, the pressure applied to the prepreg was increased to 3MPa, allowing the prepreg to cure.

[0267] As a result, if no gaps were generated between the grid pattern and the cured product and the product was filled, it was evaluated as "Good", and if gaps were generated, it was evaluated as "Poor." The presence or absence of gaps was determined by removing the copper foil from the cured product produced using a laminate molding press and shining light through it from the other side, and checking whether whitish gaps could be confirmed.

[0268] [Dielectric loss tangent before moisture absorption treatment] The dielectric loss tangent of the evaluation board (cured prepreg) at 10 GHz was measured using the cavity resonator perturbation method. Specifically, a network analyzer (Keysight Technologies N5230A) was used to measure the dielectric loss tangent of the evaluation board at 10 GHz.

[0269] [Dielectric loss tangent after moisture absorption treatment] The evaluation board used in measuring the dielectric loss tangent before the moisture absorption treatment was subjected to a moisture absorption treatment in accordance with JIS C 6481 (1996), and the dielectric loss tangent of this moisture-treated evaluation board (dielectric loss tangent after moisture absorption) was measured in the same manner as in measuring the dielectric loss tangent before the moisture absorption treatment. Note that the moisture absorption treatment involved treating the evaluation board in an environment of a temperature of 85°C and a humidity of 85% for 120 hours, after which the moisture on the evaluation board was thoroughly wiped off with a dry, clean cloth, and the measurement was then performed.

[0270] [Change in dielectric tangent (after moisture absorption treatment - before moisture absorption treatment)] The difference between the dielectric loss tangent before the moisture absorption treatment and the dielectric loss tangent after the moisture absorption treatment (dielectric loss tangent after the moisture absorption treatment - dielectric loss tangent before the moisture absorption treatment) was calculated.

[0271] [Dielectric loss tangent before heat treatment] The dielectric loss tangent of the evaluation board at 10 GHz was measured using the cavity resonator perturbation method. Specifically, a network analyzer (Keysight Technologies N5230A) was used to measure the dielectric loss tangent of the evaluation board at 10 GHz.

[0272] [Dielectric loss tangent after heat treatment] The evaluation substrate used in the measurement of the dielectric loss tangent before the heat treatment was held (heat treated) at 130°C for 120 hours, and the dielectric loss tangent of this heat-treated evaluation substrate (dielectric loss tangent after the heat treatment) was measured in the same manner as in the measurement of the dielectric loss tangent before the heat treatment.

[0273] [Change in dielectric tangent (after heat treatment - before heat treatment)] The difference between the dielectric loss tangent before and after the heat treatment (=dielectric loss tangent after the heat treatment−dielectric loss tangent before the heat treatment) was calculated.

[0274] [Glass transition temperature (DMA) (Tg)] The Tg of the cured product was measured using a viscoelasticity spectrometer "DMS6100" manufactured by Seiko Instruments Inc. Dynamic viscoelasticity measurement (DMA) was performed using a bending module at a frequency of 10 Hz, and the temperature at which tan δ reached a maximum when the temperature was raised from room temperature to 320°C at a heating rate of 5°C / min was defined as Tg.

[0275] The results of the above evaluations are shown in Table 3.

[0276] [Table 3]

[0277] (Consideration) As can be seen from Table 3, in all of the examples using the resin composition of the present invention, it was possible to obtain a cured product that had low dielectric properties, high heat resistance, and was less susceptible to the effects of changes in the external environment, and it was confirmed that a resin composition with moldability that could be applied to laminated wiring boards could be provided.

[0278] On the other hand, in Comparative Examples 1 to 3, which did not contain a free radical compound, the low dielectric properties could not be maintained due to the influence of changes in the external environment. Furthermore, in Comparative Example 1, which did not contain a free radical compound or a reaction initiator, hardening began quickly after the minimum melting, resulting in poor moldability. In Comparative Examples 2 and 3, as in Comparative Example 1, hardening also progressed quickly after the minimum melting due to the effect of the addition of the reaction initiator, resulting in poor moldability.

[0279] This application is based on Japanese Patent Application No. 2019-177945, filed on September 27, 2019, the contents of which are incorporated herein by reference.

[0280] In order to express the present invention, the present invention has been properly and sufficiently described above through embodiments with reference to specific examples, drawings, etc., but it should be recognized that those skilled in the art can easily make changes and / or improvements to the above-described embodiments. Therefore, unless changes or improvements made by those skilled in the art deviate from the scope of the claims set forth in the claims, such changes or improvements are construed as being encompassed within the scope of the claims. [Industrial Applicability]

[0281] The present invention has wide industrial applicability in the technical fields related to electronic materials and various devices using the same.

Claims

1. a polymer having a structural unit represented by the following formula (13) in the molecule; a free radical compound; and a curing agent, The free radical compound has at least one free radical group selected from the group of structures represented by the following formulas (2), (3), (4), and (5) in the molecule, and includes at least one compound selected from the compounds represented by the following formulas (6) to (8): the polymer contains a structural unit derived from divinylbenzene, a structural unit derived from ethylvinylbenzene, and a structural unit derived from styrene, and the equivalent weight of the vinyl group contained in the structural unit of the polymer is 320 to 510, and the Mw is 26,300 to 39,500; the curing agent contains at least one selected from the group consisting of a polyfunctional acrylate compound having two or more acryloyl groups in the molecule, a polyfunctional methacrylate compound having two or more methacryloyl groups in the molecule, a polyfunctional vinyl compound having two or more vinyl groups in the molecule, bromostyrene, dibromostyrene, an allyl compound having an allyl group in the molecule, a maleimide compound having a maleimide group in the molecule, and an acenaphthylene compound having an acenaphthylene structure in the molecule; the content of the free radical compound is 0.01 to 0.2 parts by mass based on the content of the polymer and the curing agent; the content of the polymer is 20 to 90 parts by mass per 100 parts by mass of the resin component (organic component) in the resin composition, the content of the curing agent is 10 to 50 parts by mass per 100 parts by mass of the total of the polymer and the curing agent; The minimum melt viscosity (T2) and the melt viscosity (T1) at a temperature 10°C above the minimum melt viscosity temperature are such that T1 / T2 is greater than 1.0 and not greater than 5.0, and T2 is not greater than 14,000 (poise); and A resin composition characterized in that the cured product has a dielectric loss tangent (10 GHz) of 0.0024 or less. 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 【Transformation 5】 【Transformation 6】 【Transformation 7】 【Transformation 8】 (In formula (6), X Ａ represents an amino group, a cyano group, a hydroxy group, an isothiocyanate group, a methoxy group, a carboxy group, an amido group, or a benzoyloxy group. In formula (7), X Ｂ represents a hydrogen atom, an amino group, a cyano group, a hydroxy group, an isothiocyanate group, a methoxy group, a carboxy group, an amido group, or a benzoyloxy group. In formula (8), X Ｃ represents an alkylene group, an aromatic structure, a carbonyl group, or an ether bond. 【Chemistry 10】

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

3. The resin composition according to claim 2 , wherein the reaction initiator comprises at least one selected from the group consisting of a metal peroxide, an azo compound, and an organic peroxide.

4. 4. The resin composition according to claim 2, wherein the content of the reaction initiator is 0.5 to 8.0 parts by mass per 100 parts by mass of the total of the polymer and the curing agent.

5. 5. The resin composition according to claim 2, wherein the ratio (mass ratio) of the free radical compound to the reaction initiator is 0.005:1 to 0.2:1.

0.

6. The resin composition according to any one of claims 1 to 5, further comprising an inorganic filler.

7. 7. The resin composition according to claim 1, further comprising a modified polyphenylene ether compound whose terminal is modified with a substituent having a carbon-carbon unsaturated double bond.

8. A prepreg comprising the resin composition according to any one of claims 1 to 7 or a semi-cured product of the resin composition and a fibrous base material.

9. A resin-coated film comprising a resin layer containing the resin composition according to any one of claims 1 to 7 or a semi-cured product of the resin composition, and a support film.

10. A resin-coated metal foil comprising a resin layer containing the resin composition according to any one of claims 1 to 7 or a semi-cured product of said resin composition, and a metal foil.

11. A metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 7 or a cured product of the prepreg according to claim 8, and a metal foil.

12. A wiring board comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 7 or a cured product of the prepreg according to claim 8, and wiring.

13. The wiring board according to claim 12 , wherein the wiring board has a plurality of insulating layers, and the wiring is disposed between the insulating layers.

14. The resin composition according to any one of claims 1 to 7, wherein T1 is 15000 (poise) or less.

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