Resin modifier and resin composition

Abstract

Provided are: a resin modifier which, by being blended with a base material, can improve adhesion of a base material or a cured product of a base material to a copper foil without causing a significant deterioration in the dielectric properties of the base material or the cured product of a base material; a resin composition containing said resin modifier and a base material resin; a cured product of said resin composition; a sheet comprising the resin composition; and a prepreg containing the cured product.　The resin modifier contains a modified resin (A) and core-shell type polymer particles (B). A modified styrene-based elastomer (A1) or a modified polyolefin-based resin (A2) is used as the modified resin. The modified resin (A) and the core-shell type polymer particles (B) are modified by a monomer having a specific polar group and an ethylenically unsaturated bond. The modified resin (A) and the core-shell type polymer particles (B) contain a common polar group.

Description

Resin modifier and resin composition

[0001] The present invention relates to a resin modifier that can be suitably blended with various resins, a resin composition containing the resin modifier and a base resin, a cured product of the resin composition, a sheet made of the resin composition, and a prepreg containing the cured product.

[0002] In recent years, there has been a demand for communication devices such as smartphones and electronic devices such as next-generation televisions to transmit and receive large amounts of data at high speeds. Accordingly, the frequencies of electrical signals are becoming increasingly higher. Specifically, in the field of wireless communications, the use of high-frequency bands of 10 GHz or higher is being considered for the introduction of fifth-generation mobile communication systems.

[0003] However, as the frequency of signals used increases, the quality of the output signal decreases, which can lead to misrecognition of information, i.e., transmission loss increases. To reduce this transmission loss, low-dielectric materials with low dielectric constants and dielectric loss tangents, which are factors related to the dielectric loss caused by insulating resins that constitute electronic components such as circuit boards, are needed. Given these circumstances, in order to obtain low-dielectric materials that can be used in high-frequency bands, it has been proposed to use styrene-based thermoplastic elastomers as resin modifiers to improve their dielectric properties. Specifically, a resin composition has been proposed that contains, as a base resin, a modified polyphenylene ether whose terminals are modified with specific radically polymerizable functional groups, and that contains a specific styrene-based thermoplastic elastomer to improve its dielectric properties (see Patent Document 1).

[0004] JP 2023-001134 A

[0005] A preferred application of the material having excellent low dielectric properties is a wiring board. The wiring board is usually a copper-clad laminate (CCL). However, a wiring board including a film or sheet made of a resin composition as described in Patent Document 1, or a wiring board impregnated with a resin composition as described in Patent Document 1, does not necessarily have good adhesion to copper foil.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a resin modifier that can be blended with a substrate to improve the adhesion of the substrate or the cured product of the substrate to copper foil without significantly deteriorating the dielectric properties of the substrate or the cured product of the substrate; a resin composition containing the resin modifier and a substrate resin; a cured product of the resin composition; a sheet made of the resin composition; and a prepreg containing the cured product.

[0007] The present inventors have conducted extensive research to solve the above problems and have completed the present invention.

[0008] That is, the present invention provides the following (1) to (15): (1) A resin modifier comprising a modified resin (A) and core-shell polymer particles (B), wherein the modified resin (A) comprises a modified styrene-based elastomer (A1) or a modified polyolefin-based resin (A2), wherein the modified resin (A) and the core-shell polymer particles (B) are modified with a monomer having an ethylenically unsaturated bond and one or more polar groups selected from the group consisting of an epoxy group, an amino group, an acid anhydride group, a hydroxy group, and a carboxy group, and wherein the type of the most abundant group among the one or more polar groups in the modified resin (A) is the same as the type of the most abundant group among the one or more polar groups in the core-shell polymer particles (B). (2) The resin modifier according to (1), wherein the most abundant group among the one or more polar groups in the modified resin (A) and the most abundant group among the one or more polar groups in the core-shell polymer particles (B) are epoxy groups. (3) The resin modifier according to (1) or (2), wherein the polar group content in the modified resin (A) is 0.1% by mass or more and 8% by mass or less, relative to the mass of the modified resin (A). (4) The resin modifier according to any one of (1) to (3), wherein the polar group content in the core-shell polymer particles (B) is 0.5% by mass or more and 10% by mass or less, relative to the mass of the core-shell polymer particles (B). (5) The resin modifier according to any one of (1) to (4), wherein the modified resin (A) comprises a modified styrene-based elastomer (A1), and comprises 25 parts by mass or more and 98 parts by mass or less of the modified resin (A) and 2 parts by mass or more and 75 parts by mass or less of the core-shell polymer particles (B) relative to 100 parts by mass of the resin modifier. (6) The resin modifier according to any one of (1) to (4), wherein the modified resin (A) comprises the modified polyolefin resin (A2), the ratio of the mass of the modified resin (A) to the total mass of the modified resin (A) and the mass of the core-shell polymer particles (B) is 25% by mass or more and 90% by mass or less, and the ratio of the mass of the core-shell polymer particles (B) to the total mass of the modified resin (A) and the mass of the core-shell polymer particles (B) is 10% by mass or more and 75% by mass or less.(7) The resin modifier according to any one of (1) to (4) and (6), wherein the modified resin (A) comprises a modified polyolefin resin (A2) and further comprises a styrene-based elastomer (C). (8) The resin modifier according to claim 7, wherein the ratio of the mass of the styrene-based elastomer (C) to the total mass of the modified resin (A) and the core-shell polymer particles (B) is 20% by mass or more and 70% by mass or less. (9) The resin modifier according to (7) or (8), wherein the styrene-based elastomer (C) comprises at least one selected from the group consisting of styrene / isoprene / styrene elastomer, styrene / isobutylene / styrene elastomer, styrene / ethylenebutylene / styrene elastomer, hydrogenated styrene / isoprene / styrene elastomer, and hydrogenated styrene / (butadiene / isoprene) / styrene elastomer. (10) A resin composition comprising one or more substrates selected from resins and curable compounds, and the resin modifier according to any one of (1) to (9), wherein, when the modified resin (A) contains a modified styrene-based elastomer (A1), the sum of the mass of the modified resin (A) and the mass of the core-shell polymer particles (B) is 0.1 parts by mass or more and 80 parts by mass or less, relative to 100 parts by mass of the substrate, and when the modified resin (A) contains a modified polyolefin-based resin (A2), the sum of the mass of the modified resin (A) and the mass of the core-shell polymer particles (B) is 5 parts by mass or more and 80 parts by mass or less, relative to 100 parts by mass of the substrate. (11) The resin composition according to (10), wherein the substrate is polyphenylene ether. (12) The resin composition according to (10) or (11), further comprising a radical polymerization initiator, and the substrate comprises a radically polymerizable compound as a curable compound, the content of the radically polymerizable compound being 20% ​​by mass or more and 100% by mass or less relative to the mass of the substrate. (13) A cured product of the resin composition according to (8). (14) A sheet comprising the resin composition according to (6) or (7). (15) A prepreg comprising a fiber sheet and the cured product according to (13) composited with the fiber sheet.

[0009] According to the present invention, it is possible to provide a resin modifier that can be blended with a substrate to improve the adhesion of the substrate or the cured product of the substrate to copper foil without significantly deteriorating the dielectric properties of the substrate or the cured product of the substrate; a resin composition containing the resin modifier and the substrate; a cured product of the resin composition; a sheet made of the resin composition; and a prepreg containing the cured product.

[0010] <<Resin Modifier>> The resin modifier includes a modified resin (A) and core-shell polymer particles (B). The modified resin (A) includes a modified styrene-based elastomer (A1) or a modified polyolefin-based resin (A2). The modified resin (A) and the core-shell polymer particles (B) are modified with a monomer having an ethylenically unsaturated bond and one or more polar groups selected from the group consisting of an epoxy group, an amino group, an acid anhydride group, a hydroxy group, and a carboxy group. The type of the most abundant group among the one or more polar groups contained in the modified resin (A) is the same as the type of the most abundant group among the one or more polar groups contained in the core-shell polymer particles (B).

[0011] The resin modifier is blended into a substrate, and when blended into the substrate, the adhesiveness of the substrate or the cured product of the substrate to copper foil can be improved without significantly deteriorating the dielectric properties of the substrate or the cured product of the substrate.

[0012] Hereinafter, the resin modifier will be described for the case where the modified resin (A) contains a modified styrene-based elastomer (A1) and the case where the modified resin (A) contains a modified polyolefin-based resin (A2). Hereinafter, the resin modifier containing the modified styrene-based elastomer (A1) will also be referred to as the "first modifier." Hereinafter, the resin modifier containing the modified polyolefin-based resin (A2) will also be referred to as the "second modifier."

[0013] <First Modifier> The first modifier preferably contains 25 to 98 parts by mass of modified resin (A) and 2 to 75 parts by mass of core-shell polymer particles (B) relative to 100 parts by mass of the first modifier. The lower limit of the content of modified resin (A) in the first modifier may be 30 parts by mass or more, 40 parts by mass or more, or 50 parts by mass or more relative to 100 parts by mass of the first modifier. The upper limit of the content of modified resin (A) in the first modifier may be 80 parts by mass or less, 70 parts by mass or less, or 60 parts by mass or less relative to 100 parts by mass of the first modifier. The lower limit of the content of the core-shell polymer particles (B) in the first modifier may be 5 parts by mass or more, 10 parts by mass or more, 20 parts by mass or more, 30 parts by mass or more, or 40 parts by mass or more, relative to 100 parts by mass of the first modifier. The upper limit of the content of the core-shell polymer particles (B) in the first modifier may be 70 parts by mass or less, 60 parts by mass or less, or 50 parts by mass or less, relative to 100 parts by mass of the first modifier.

[0014] Essential and optional components contained in the first modifier will be described below.

[0015] [Modified Resin (A)] The modified resin (A) is a resin modified with a monomer having an ethylenically unsaturated bond and one or more polar groups selected from the group consisting of an epoxy group, an amino group, an acid anhydride group, a hydroxy group, and a carboxy group. The structural unit derived from the monomer having a polar group and an ethylenically unsaturated bond is typically bonded to the resin as a side chain by graft polymerization. The structural unit derived from the monomer having a polar group and an ethylenically unsaturated bond may be bonded to the main chain of the resin by copolymerizing the monomer having a polar group and an ethylenically unsaturated bond with the main monomer constituting the resin.

[0016] The content of polar groups in the modified resin (A) is not particularly limited as long as the desired effect is not impaired. The content of polar groups in the modified resin (A) is preferably 0.1% by mass or more and 8% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, and even more preferably 0.1% by mass or more and 3% by mass or less, relative to the mass of the modified resin (A). The content of polar groups in the modified resin (A) can be measured by various methods depending on the type of polar group. When the polar group is an epoxy group, for example, the content of epoxy groups in the modified resin (A) can be measured using a potentiometric titrator in accordance with JIS K7236.

[0017] In addition, the type of the most abundant group among the one or more polar groups of the modified resin (A) is the same as the type of the most abundant group among the one or more polar groups of the core-shell polymer particles (B) described later.The ratio of the mass of the most abundant polar group to the total mass of the polar groups of the modified resin (A) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass.The ratio of the mass of the most abundant polar group to the total mass of the polar groups of the core-shell polymer particles (B) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass.

[0018] The modified resin (A) contains a modified styrene-based elastomer (A1). The modified resin (A) may contain a modified resin other than the modified styrene-based elastomer (A1) to the extent that the desired effect is not impaired. Examples of modified resins other than the modified styrene-based elastomer (A1) include the modified polyolefin-based resin (A2), modified (meth)acrylic resin, modified polystyrene resin, modified polyphenylene ether resin, modified silicone resin, modified polyester resin, and modified fluororesin, which will be described later. Among these, the modified polyolefin-based resin (A2) is preferred. These modified resins other than the modified styrene-based elastomer (A1) can be obtained by using the aforementioned specific monomer having a polar group and an ethylenically unsaturated bond when producing the modified resin, or by reacting the aforementioned specific monomer having a polar group and an ethylenically unsaturated bond with the main chain of the resin to introduce a branch having a polar group and an ethylenically unsaturated bond into the main chain.

[0019] The content of the modified styrene-based elastomer (A1) in the modified resin (A) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 95% by mass or more, and particularly preferably 100% by mass, based on the mass of the modified resin (A).

[0020] (Modified Styrenic Elastomer (A1)) The styrene elastomer is a block copolymer containing a polystyrene block derived from a styrene monomer consisting of styrene and a styrene derivative. The modified styrene elastomer (A1) is a modified resin obtained by modifying the above styrene elastomer with a monomer having an ethylenically unsaturated bond and one or more polar groups selected from the group consisting of an epoxy group, an amino group, an acid anhydride group, a hydroxy group, and a carboxy group.

[0021] The styrene monomer used as a raw material for the styrene elastomer is not particularly limited. Suitable examples of the styrene monomer include styrene, 4-methylstyrene, α-methylstyrene, 2,6-dimethylstyrene, 2,4-dimethylstyrene, α-methyl-4-methylstyrene, 2,4,6-trimethylstyrene, α-methyl-2,4-dimethylstyrene, 4-chlorostyrene, α-chloro-4-chlorostyrene, 2,4,6-trichlorostyrene, α-chloro-2,4-dichlorostyrene, 4-tert-butylstyrene, 4-methoxystyrene, 4-chloromethylstyrene, and styrene derivatives substituted with a silyl group. Of the above styrene monomers, styrene, α-methylstyrene, and 4-methylstyrene are preferred, and styrene and α-methylstyrene are more preferred from the standpoint of cost.

[0022] The blocks other than the polystyrene block in the styrene elastomer may be any of various known blocks conventionally used in styrene elastomers. Preferred styrene elastomers include styrene / isoprene / styrene elastomer, styrene / isobutylene / styrene elastomer, styrene / ethylenebutylene / styrene elastomer, hydrogenated styrene / isoprene / styrene elastomer, and hydrogenated styrene / (butadiene / isoprene) / styrene elastomer. The polystyrene block in the styrene elastomer may be a block made of polystyrene, a block made of a homopolymer of a styrene derivative, or a block made of a copolymer of two or more styrene monomers. The polystyrene block in the styrene elastomer is preferably a block made of polystyrene.

[0023] Among the polar groups possessed by the monomers used for modification, epoxy groups are preferred because they have an excellent effect of improving the adhesion between the substrate containing the first modifier or the cured product of the substrate and the copper foil. The monomer having a polar group and an ethylenically unsaturated bond may have two or more polar groups. As the monomer having a polar group and an ethylenically unsaturated bond, a compound having one or two polar groups is preferred, and a compound having one polar group is more preferred.

[0024] Examples of the monomer having a polar group and an ethylenically unsaturated bond include unsaturated group-containing epoxy compounds such as glycidyl (meth)acrylate, monoglycidyl maleate, diglycidyl maleate, monoglycidyl itaconate, monoglycidyl allyl succinate, 4-carboxystyrene, styrene glycidyl ester, allyl glycidyl ether, methacrylic glycidyl ether, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene, and vinylcyclohexene monoxide; Examples of the unsaturated amine include unsaturated amines such as maleic anhydride, vinylsuccinic acid, and allylsuccinic acid; unsaturated group-containing acid anhydrides such as maleic anhydride, vinylsuccinic acid, and allylsuccinic acid; hydroxyl group-containing unsaturated compounds such as 2-hydroxyethyl (meth)acrylate, allyl alcohol, methallyl alcohol, 1-butenyl alcohol, and 4-hydroxystyrene; and unsaturated carboxylic acids such as (meth)acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, and crotonic acid. When producing the modified styrene elastomer (A1), two or more types of monomers having a polar group and an ethylenically unsaturated bond may be used in combination.

[0025] The modification with a monomer having a polar group and an ethylenically unsaturated bond may be graft modification, or may be modification in which a monomer having a polar group and an ethylenically unsaturated bond is incorporated into a block constituting the styrene-based elastomer by copolymerization.

[0026] When the modified styrene-based elastomer (A1) is graft-modified, the modified styrene-based elastomer (A1) is obtained by graft-modifying the styrene-based elastomer with a monomer having a polar group and an ethylenically unsaturated bond in the presence of a radical polymerization initiator.

[0027] The graft-modified styrene-based elastomer (A1) is preferably graft-modified with a monomer having a polar group and an ethylenically unsaturated bond and an aromatic vinyl monomer not having a polar group, and more preferably graft-modified with glycidyl (meth)acrylate and styrene.

[0028] Examples of radical polymerization initiators that can be used when graft-modifying a styrene-based elastomer include methyl ethyl ketone peroxide, methyl acetoacetate peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,2-bis(tert-butylperoxy)butane, permethane hydroperoxide, cumene hydroperoxide, dicumyl peroxide, α,α'-bis(tert-butylperoxy-m-isopropyl)benzene, di-tert-butyl peroxide, benzoyl peroxide, di(3-methyl-3-methoxybutyl)peroxydicarbonate, di-2-methoxybutyl peroxydicarbonate, tert-butylperoxyoctate, tert-butylperoxyisobutyrate, and di-tert-butylperoxyisophthalate. The above radical polymerization initiators can be used alone or in combination of two or more.

[0029] The amount of the radical polymerization initiator used is not particularly limited as long as the graft modification reaction proceeds smoothly, and is preferably 0.01 parts by mass or more and 10 parts by mass or less, and more preferably 0.2 parts by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the styrene-based elastomer.

[0030] The amount of the monomer having a polar group and an ethylenically unsaturated bond used for graft modification of the styrene-based elastomer to be added is preferably 0.1 parts by mass or more and 12 parts by mass or less, more preferably 0.5 parts by mass or more and 10 parts by mass or less, and particularly preferably 1 part by mass or more and 8 parts by mass or less, relative to 100 parts by mass of the styrene-based elastomer.

[0031] By using the modified styrene-based elastomer (A1) modified with a monomer having a polar group and an ethylenically unsaturated bond in amounts within the above ranges, an excellent effect of improving the adhesion of a substrate containing the first modifier or a cured product of the substrate to a copper foil can be achieved.

[0032] As described above, the graft-modified modified styrene-based elastomer (A1) is preferably graft-modified with a monomer having a polar group and an ethylenically unsaturated bond, and an aromatic vinyl monomer having no polar group.

[0033] By using a monomer having a polar group and an ethylenically unsaturated bond in combination with an aromatic vinyl monomer having no polar group, the grafting reaction is stabilized, making it easier to graft a desired amount of the vinyl monomer having a polar group.

[0034] Specific examples of aromatic vinyl monomers having no polar group include styrene, 4-methylstyrene, α-methylstyrene, 4-chlorostyrene, α-chlorostyrene, dichlorostyrene, 4-bromostyrene, dibromostyrene, 4-fluorostyrene, difluorostyrene, 4-nitrostyrene, and dinitrostyrene.

[0035] Among these aromatic vinyl monomers, styrene, α-methylstyrene, 4-methylstyrene, 1,2-divinylbenzene, 1,3-divinylbenzene, 1,4-divinylbenzene, or a mixture of divinylbenzene isomers is preferred from the viewpoint of low cost, and styrene is particularly preferred.

[0036] The aromatic vinyl monomers can be used alone or in combination of two or more.

[0037] The amount of the aromatic vinyl monomer having no polar group used for graft modification of the styrene-based elastomer is preferably 0.1 parts by mass or more and 12 parts by mass or less, more preferably 0.5 parts by mass or more and 10 parts by mass or less, and particularly preferably 1 part by mass or more and 8 parts by mass or less, relative to 100 parts by mass of the styrene-based elastomer.

[0038] When the modified styrene elastomer (A1) contains a structural unit derived from a monomer having a polar group and an ethylenically unsaturated bond in the main chain, the modified styrene elastomer (A1) can be obtained by copolymerizing a monomer that gives a block constituting the styrene elastomer with a monomer having a polar group and an ethylenically unsaturated bond according to a well-known method. In this case, the preferred styrene elastomer is the same as that used in producing the modified styrene elastomer (A1) by graft modification.

[0039] [Core-shell polymer particles (B)] The core-shell polymer particles (B) have a core-shell structure and are polymer particles modified with a monomer having an ethylenically unsaturated bond and one or more polar groups selected from the group consisting of an epoxy group, an amino group, an acid anhydride group, a hydroxy group, and a carboxy group. The monomer having a polar group and an ethylenically unsaturated bond is as described above for the modified resin (A). The core and the shell may each be composed of two or more layers. In the core-shell polymer particles (B), the outermost layer of the shell layer is usually modified with the above-mentioned monomer having a polar group and an ethylenically unsaturated bond.

[0040] The content of polar groups in the core-shell polymer particles (B) is not particularly limited as long as the desired effect is not impaired. The content of polar groups in the core-shell polymer particles (B) is preferably 0.5% by mass or more and 10% by mass or less, more preferably 0.7% by mass or more and 8% by mass or less, and even more preferably 1% by mass or more and 6% by mass or less, relative to the mass of the core-shell polymer particles (B). The content of polar groups in the core-shell polymer particles (B) can be measured by various methods depending on the type of polar group. When the polar group is an epoxy group, for example, the content of epoxy groups in the core-shell polymer particles (B) can be measured using a potentiometric titrator in accordance with JIS K7236.

[0041] The core-shell polymer particles (B) preferably have a core made of a crosslinked polymer.

[0042] The ratio of the mass of the core to the mass of the shell in the core-shell polymer particles, in terms of core / shell, is preferably from 50 / 50 to 99 / 1, more preferably from 60 / 40 to 95 / 5, and even more preferably from 70 / 30 to 90 / 10.

[0043] The core is preferably made of a crosslinked polymer. The crosslinked polymer is substantially insoluble in a solvent. The gel content of the core is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0044] The core is preferably a rubbery elastomer that is a polymer of monomers consisting of 50% by mass to 100% by mass of one or more monomers selected from the group consisting of diene monomers and (meth)acrylic acid ester monomers and 0% by mass to 50% by mass of other copolymerizable vinyl monomers, and the other copolymerizable vinyl monomers are preferably one or more selected from the group consisting of aromatic vinyl compounds, vinyl cyanide compounds, unsaturated carboxylic acid derivatives, (meth)acrylamide derivatives, and maleimide derivatives.

[0045] The core is more preferably made of a rubbery elastomer which is a polymer of monomers consisting of 60% by mass or more and 100% by mass or less of one or more monomers selected from the group consisting of diene-based monomers and (meth)acrylic acid ester-based monomers and 0% by mass or more and 40% by mass or less of other copolymerizable vinyl monomers, and even more preferably made of a rubbery elastomer which is a polymer of monomers consisting of 70% by mass or more and 100% by mass or less of one or more monomers selected from the group consisting of diene-based monomers and (meth)acrylic acid ester-based monomers and 0% by mass or more and 30% by mass or less of other copolymerizable vinyl monomers.

[0046] Hereinafter, "a monomer selected from the group consisting of a diene monomer and a (meth)acrylic acid ester monomer" will be referred to as "monomer A." The other copolymerizable vinyl monomer is a vinyl monomer copolymerizable with monomer A. Furthermore, "(meth)acrylic" means both acrylic and methacrylic.

[0047] Examples of diene monomers include butadiene, isoprene, and chloroprene, with butadiene being preferred. Examples of (meth)acrylic acid ester monomers include butyl acrylate, 2-ethylhexyl acrylate, and lauryl methacrylate, with butyl acrylate and 2-ethylhexyl acrylate being preferred. These monomers may be used alone or in combination of two or more.

[0048] The amount of the monomer A used is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on the mass of the core.

[0049] The core may be a homopolymer obtained by polymerizing one type of monomer A, or may be a copolymer of two or more types of monomer A. The core may also be a copolymer of one or more types of monomer A and one or more vinyl monomers copolymerizable with the monomer A.

[0050] Examples of vinyl monomers copolymerizable with monomer A include one or more monomers selected from the group consisting of aromatic vinyl compounds, vinyl cyanide compounds, unsaturated carboxylic acid derivatives, (meth)acrylamide derivatives, and maleimide derivatives. Examples of aromatic vinyl compounds include styrene, α-methylstyrene, and vinylnaphthalene. Examples of vinyl cyanide compounds include (meth)acrylonitrile and substituted acrylonitrile. Examples of unsaturated carboxylic acid derivatives include (meth)acrylic acid, itaconic acid, crotonic acid, and maleic anhydride. Examples of (meth)acrylamide derivatives include (meth)acrylamide and N-substituted (meth)acrylamide. Examples of maleimide derivatives include maleimide and N-substituted maleimide. These monomers may be used alone or in combination of two or more.

[0051] The amount of these copolymerizable vinyl monomers used is preferably 50% by weight or less, more preferably 40% by weight or less, based on the mass of the core.

[0052] When preparing the polymer constituting the core, a crosslinkable monomer may be used for the purpose of suppressing swelling of the core due to a solvent. Examples of the crosslinkable monomer include divinylbenzene, butanediol di(meth)acrylate, triallyl (iso)cyanurate, allyl (meth)acrylate, diallyl itaconate, and diallyl phthalate. The amount of the crosslinkable monomer used is preferably 0.2% by mass or more and 7% by mass or less, more preferably 0.5% by mass or more and 5% by mass or less, and even more preferably 1% by mass or more and 3% by mass or less, based on the mass of the core-shell polymer particles (B).

[0053] In addition, coating the core with a crosslinkable monomer and forming an intermediate layer between the core and the shell is effective in suppressing fusion between the core-shell polymer particles (B). The crosslinkable monomer used to form the intermediate layer is not particularly limited, but a trialkenyl isocyanurate compound such as triallyl isocyanurate (TAIC) is preferred.

[0054] In addition, a chain transfer agent may be used in the polymerization of the core to adjust the molecular weight and / or degree of crosslinking of the polymer constituting the core layer. Usable chain transfer agents include, for example, alkyl mercaptans having 5 to 20 carbon atoms. The amount of chain transfer agent used is preferably 5% by mass or less, more preferably 3% by mass or less, based on the mass of the core.

[0055] The core may contain a crosslinked aromatic vinyl. Examples of the crosslinked aromatic vinyl include copolymers of aromatic vinyl compounds and the above-mentioned crosslinkable monomers. Examples of the aromatic vinyl compounds include styrene, 2-vinylnaphthalene, α-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,5-dimethylstyrene, 2,4,6-trimethylstyrene, 4-methoxystyrene, 4-ethoxystyrene, and 2-chlorostyrene.

[0056] The core may contain a polysiloxane rubber-based elastomer. The polysiloxane rubber-based elastomer is preferably a polysiloxane rubber composed of di-substituted silyloxy units, such as dimethylsilyloxy, methylphenylsilyloxy, or diphenylsilyloxy. The polysiloxane rubber-based elastomer is preferably crosslinked, as needed, by using a polyfunctional alkoxysilane having three or more functional groups or a silane compound having an unsaturated group.

[0057] The shell is a layer formed by graft polymerizing a graft copolymerizable monomer (shell-forming monomer) onto the core.

[0058] The "shell" is a layer at least part of which is present on the outermost side of the core-shell polymer particle (B). The entire shell does not necessarily have to be present on the outermost side of the core-shell polymer particle (B). A part of the shell may extend into the core.

[0059] The type of polymer constituting the shell is not particularly limited, and the polymer constituting the shell is preferably a polymer of one or more monomers selected from a (meth)acrylic acid ester monomer, an aromatic vinyl monomer, a vinyl cyanide monomer, an unsaturated carboxylic acid derivative, a (meth)acrylamide derivative, and a maleimide derivative.

[0060] Examples of (meth)acrylic acid ester monomers include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Examples of aromatic vinyl monomers include styrene, α-methylstyrene, 4-bromostyrene, 2-chlorostyrene, and 4-chlorostyrene. Examples of vinyl cyanide monomers include (meth)acrylonitrile and substituted (meth)acrylonitrile. Examples of unsaturated carboxylic acid derivatives include (meth)acrylic acid, itaconic acid, crotonic acid, and maleic anhydride. Examples of (meth)acrylamide derivatives include (meth)acrylamide and N-substituted (meth)acrylamide. Examples of maleimide derivatives include maleimide and N-substituted maleimide.

[0061] The styrene units preferably account for 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more of the mass of the core-shell polymer particles (B).

[0062] The core-shell polymer particles (B) are modified with a monomer having one or more polar groups selected from the group consisting of an epoxy group, an amino group, an acid anhydride group, a hydroxy group, and a carboxy group, and an ethylenically unsaturated bond. Therefore, in the core-shell polymer particles (B), it is preferred that the resin constituting the shell contains a structural unit derived from the monomer having the polar group and the ethylenically unsaturated bond, or that the resin constituting the shell is graft-polymerized with the monomer having the polar group and the ethylenically unsaturated bond.

[0063] When modifying the core-shell polymer particles, a monomer having a polar group and an ethylenically unsaturated bond is used so that the ratio of the mass of the polar group to the mass of the core-shell polymer particles (B) falls within the above-mentioned preferred range.

[0064] The shell may have a single layer structure or a multi-layer structure, and when the shell has a multi-layer structure, the polymer composition of each layer may be different.

[0065] The volume average particle diameter of the core-shell polymer particles (B) is preferably 10 nm to 400 nm, more preferably 30 nm to 350 nm, even more preferably 50 nm to 300 nm, still more preferably 80 nm to 250 nm, and particularly preferably 100 nm to 200 nm. The volume average particle diameter of the core-shell polymer particles (B) can be measured using, for example, a laser diffraction / scattering particle size distribution analyzer such as Microtrac (Microtrac UPA, manufactured by Nikkiso Co., Ltd.).

[0066] The volume average particle diameter of the core-shell polymer particles (B) is preferably 10 nm or more and 400 nm or less, more preferably 30 nm or more and 350 nm or less, even more preferably 50 nm or more and 300 nm or more, even more preferably 80 nm or more and 250 nm or less, and particularly preferably 100 nm or more and 200 nm or less. The volume average particle diameter of the core-shell polymer particles (B) can be measured using, for example, a laser diffraction / scattering particle size distribution analyzer such as Microtrac (Microtrac UPA, manufactured by Nikkiso Co., Ltd.). When measuring the particle diameter using a laser diffraction / scattering particle size distribution analyzer, the core-shell polymer particles (B) are usually dispersed in the measurement sample as primary particles. Therefore, the volume average particle diameter measured using a laser diffraction / scattering particle size distribution analyzer can be used as the average primary particle diameter.

[0067] The method for producing the core-shell polymer particles (B) is not particularly limited. The core-shell polymer particles (B) can be produced by a well-known method. Examples of well-known methods include emulsion polymerization, suspension polymerization, and microsuspension polymerization. Among these methods, a production method using multistage emulsion polymerization is particularly suitable.

[0068] [Other Components] The first modifier may contain other components in addition to the modified resin (A) and the core-shell polymer particles (B) depending on the application of the resin composition obtained by blending the first modifier with a resin.

[0069] Examples of other components include various additives such as compatibilizers, fillers, antioxidants, heat stabilizers, light stabilizers, flame retardants, lubricants, antistatic agents, colorants, rust inhibitors, crosslinking agents, foaming agents, fluorescent agents, surface smoothing agents, surface gloss improvers, and mold release improvers.

[0070] The first modifier may also contain an organic solvent if necessary. Preferred examples of the organic solvent include ketones such as methyl ethyl ketone and methyl isobutyl ketone; aliphatic hydrocarbons such as pentane, cyclopentane, hexane, cyclohexane, octane, decane, and dodecane; aromatic hydrocarbons such as benzene, toluene, and xylene; ethers such as diethyl ether, diisopropyl ether, and tetrahydrofuran; and halogenated hydrocarbons such as methylene chloride, methyl chloroform, carbon tetrachloride, dichlorodifluoromethane, and perchloroethylene. Two or more of these organic solvents may be used in combination.

[0071] When the first modifier contains an organic solvent, the solid content concentration of the first modifier is not particularly limited, and is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

[0072] The first modifier can be obtained by uniformly mixing the modified resin (A) and the core-shell polymer particles (B) described above together with other additives as necessary. Preferably, the first modifier is prepared by mixing a solution of the modified resin (A) in an organic solvent with a dispersion of the core-shell polymer particles (B) dispersed in an organic solvent.

[0073] <Second modifier> The second modifier preferably contains 25% by mass or more and 90% by mass or less of the modified resin (A) relative to the total mass of the modified resin (A) and the core-shell polymer particles (B). The second modifier preferably contains 10% by mass or more and 75% by mass or less of the core-shell polymer particles (B) relative to the total mass of the modified resin (A) and the core-shell polymer particles (B). In the second modifier, the lower limit of the mass ratio of the modified resin (A) relative to the total mass of the modified resin (A) and the core-shell polymer particles (B) may be 30% by mass or more, 40% by mass or more, or 50% by mass or more. In the second modifier, the upper limit of the mass ratio of the modified resin (A) relative to the total mass of the modified resin (A) and the core-shell polymer particles (B) may be 80% by mass or less, 70% by mass or less, or 60% by mass or less. The lower limit of the content of the core-shell polymer particles (B) in the second modifier may be 20 parts by mass or more, 30 parts by mass or more, or 40 parts by mass or more, relative to 100 parts by mass of the second modifier. The upper limit of the content of the core-shell polymer particles (B) in the second modifier may be 70 parts by mass or less, 60 parts by mass or less, or 50 parts by mass or less, relative to 100 parts by mass of the second modifier.

[0074] Essential and optional components contained in the second modifier will be described below.

[0075] [Modified Resin (A)] The modified resin (A) is the same as the modified resin (A) in the first modifier, except that the modified resin (A) essentially contains the modified polyolefin resin (A2).

[0076] The modified resin (A) includes a modified polyolefin resin (A2). The modified resin (A) may contain a modified resin other than the modified polyolefin resin (A1) as long as the desired effect is not impaired. Examples of modified resins other than the modified polyolefin resin (A2) include the aforementioned modified styrene elastomer (A1), modified (meth)acrylic resin, modified polystyrene resin, modified polyphenylene ether resin, modified silicone resin, modified polyester resin, and modified fluororesin. Among these, the modified styrene elastomer (A1) is preferred. These modified resins other than the modified polyolefin resin (A2) can be obtained by using a monomer having the aforementioned specific polar group and an ethylenically unsaturated bond when producing the modified resin, or by reacting the aforementioned monomer having the aforementioned specific polar group and an ethylenically unsaturated bond with the main chain of the resin to introduce a branch having a polar group into the main chain.

[0077] The content of the modified polyolefin resin (A2) in the modified resin (A) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 100% by mass, based on the mass of the modified resin (A).

[0078] (Modified Polyolefin Resin (A2)) The modified polyolefin resin (A2) is a polyolefin resin modified with a monomer having one or more polar groups selected from the group consisting of an epoxy group, an amino group, an acid anhydride group, a hydroxy group, and a carboxy group, and an ethylenically unsaturated bond. Among the polar groups possessed by these monomers, an epoxy group is preferred because it has an excellent effect of improving the adhesion of a resin composition containing the resin modifier to copper foil. The monomer having a polar group and an ethylenically unsaturated bond may have two or more polar groups. As the monomer having a polar group and an ethylenically unsaturated bond, a compound having one or two polar groups is preferred, and a compound having one polar group is more preferred.

[0079] The monomer having a polar group and an ethylenically unsaturated bond may be the same as that described above for the modified styrene elastomer (A1). When producing the modified polyolefin resin (A2), two or more types of monomers having a polar group and an ethylenically unsaturated bond may be used in combination.

[0080] When the modified polyolefin resin (A2) is graft-modified, the modified polyolefin resin (A2) is obtained by graft-modifying the polyolefin resin with a monomer having a polar group and an ethylenically unsaturated bond in the presence of a radical polymerization initiator.

[0081] The graft-modified polyolefin resin (A2) is preferably graft-modified with a monomer having a polar group and an ethylenically unsaturated bond and an aromatic vinyl monomer having no polar group. By using a monomer having a polar group and an ethylenically unsaturated bond in combination with an aromatic vinyl monomer having no polar group, the graft reaction is stabilized, making it easy to graft a desired amount of the monomer having a polar group and an ethylenically unsaturated bond. Among these, graft-modification with glycidyl (meth)acrylate and styrene is more preferred.

[0082] Examples of polyolefin resins include linear polyolefins such as polyethylene, polypropylene, poly-1-butene, polyisobutylene, polymethylpentene, propylene-ethylene copolymer, ethylene-propylene-diene copolymer, ethylene / butene-1 copolymer, and ethylene / octene copolymer; and cyclic polyolefins such as copolymers of cyclopentadiene with ethylene and / or propylene.

[0083] Among these polyolefin resins, polymethylpentene, polyethylene, polypropylene, and propylene-ethylene copolymers are preferred because they are easily modified, and polymethylpentene is preferred from the standpoints of heat resistance and low dielectric properties.

[0084] Examples of the radical polymerization initiator that can be used when graft-modifying the polyolefin resin include the above-mentioned radical polymerization initiators that can be used when producing the graft-modified styrene elastomer (A1).

[0085] The amount of the radical polymerization initiator used is not particularly limited as long as the graft modification reaction proceeds smoothly, and is preferably 0.01 parts by mass or more and 10 parts by mass or less, and more preferably 0.2 parts by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the polyolefin resin.

[0086] The amount of the monomer having a polar group and an ethylenically unsaturated bond used for graft modification of the polyolefin resin to be added is preferably 0.1 parts by mass or more and 12 parts by mass or less, more preferably 0.5 parts by mass or more and 10 parts by mass or less, and particularly preferably 1 part by mass or more and 8 parts by mass or less, per 100 parts by mass of the polyolefin resin.

[0087] By using the modified polyolefin resin (A2) modified with a monomer having a polar group and an ethylenically unsaturated bond in amounts within this range, the resin composition containing the resin modifier has an excellent effect of improving adhesion to copper foil.

[0088] The type and amount of the aromatic vinyl monomer having no polar group are the same as those described for the modified styrene elastomer (A1).

[0089] When the modified polyolefin resin (A2) contains a structural unit derived from a monomer having a polar group and an ethylenically unsaturated bond in the main chain, the modified polyolefin resin can be obtained by copolymerizing an olefin that gives a polyolefin resin with a monomer having a polar group and an ethylenically unsaturated bond according to a well-known method. In this case, the preferred polyolefin resin is the same as that when the modified polyolefin resin (A2) is produced by graft modification.

[0090] [Core-shell polymer particles (B)] The core-shell polymer particles (B) are the same as those described for the first modifier.

[0091] [Styrene-based elastomer (C)] The second modifier preferably contains a styrene-based elastomer (C) as a compatibilizer to improve compatibility with the radically polymerizable compound contained in the base material, etc. As the styrene-based elastomer (C), any conventionally known styrene-based elastomer can be used without any particular limitation.

[0092] The amount of the styrene-based elastomer (C) used is not particularly limited as long as the desired effect is not impaired. The amount of the styrene-based elastomer (C) used is preferably 20% by mass or more and 70% by mass or less, more preferably 20% by mass or more and 60% by mass or less, based on the total mass of the modified resin (A) and the core-shell polymer particles (B).

[0093] Suitable examples of the styrene-based elastomer (C) include at least one selected from the group consisting of styrene / isoprene / styrene elastomer, styrene / isobutylene / styrene elastomer, styrene / ethylenebutylene / styrene elastomer, hydrogenated styrene / isoprene / styrene elastomer, and hydrogenated styrene / (butadiene / isoprene) / styrene elastomer.

[0094] The second modifier may contain other components in addition to the modified resin (A), the core-shell polymer particles (B), and the styrene-based elastomer (C), depending on the application of the resin composition obtained by blending the second modifier with the resin.

[0095] Other components that the second modifier may contain are the same as those that the first modifier may contain. The second modifier may also contain an organic solvent, if necessary. The organic solvent that the second modifier may contain is the same as that that the first modifier may contain.

[0096] Resin composition The resin composition includes a substrate and the resin modifier described above. The substrate is one or more selected from a resin and a curable compound. In the resin composition, the total mass of the modified resin (A) derived from the first modifier and the mass of the core-shell polymer particles (B) is 0.1 parts by mass or more and 80 parts by mass or less, preferably 1 part by mass or more and 77 parts by mass or less, more preferably 5 parts by mass or more and 75 parts by mass or less, and even more preferably 10 parts by mass or more and 70 parts by mass or less, relative to 100 parts by mass of the substrate. In the resin composition, the total mass of the modified resin (A) derived from the second modifier and the mass of the core-shell polymer particles (B) is 5 parts by mass or more and 80 parts by mass or less, more preferably 10 parts by mass or more and 70 parts by mass or less, relative to 100 parts by mass of the substrate.

[0097] The resin used as the substrate is not particularly limited as long as it is a resin capable of dispersing the core-shell polymer particles (B) in a particulate form. The form of the resin composition is also not particularly limited. The resin composition is preferably a varnish-like composition containing the substrate and the modified resin (A) dissolved in an organic solvent and the core-shell polymer particles (B) dispersed in the organic solvent.

[0098] The organic solvent that the resin composition may contain is the same as the organic solvent that the resin modifier may contain.

[0099] When the resin composition is a varnish-like composition containing an organic solvent, the solid content of the resin composition is preferably 20% by mass or more and 80% by mass or less, and more preferably 30% by mass or more and 70% by mass or less.

[0100] The substrate is one or more selected from a resin and a curable compound. When the resin composition is a curable compound, the resin composition may contain a curing agent depending on the type of curable composition. Typical examples of the curable compound include a radically polymerizable compound and a cationically polymerizable compound. Radical polymerizable compounds will be described later. Examples of cationically polymerizable compounds include epoxy compounds, oxetane compounds, and vinyl ether compounds. Typically, a polymer having a number-average molecular weight of 10,000 or more is a resin, and a compound having a number-average molecular weight of less than 10,000 and a polymerizable group is a polymerizable compound. Furthermore, the resin may have a radically polymerizable group or a cationically polymerizable group as the polymerizable group. Radical polymerizable groups will be described later. Examples of cationically polymerizable groups include an epoxy group, an oxetanyl group, and a vinyloxy group. In the specification of the present application, a polymer having a polymerizable group and a number-average molecular weight of 10,000 or more is referred to as a "resin" for convenience. As the resin for the substrate, for example, polyphenylene ether resin, polyolefin resin, and styrene-based elastomer are preferred because they have good dielectric properties in the high frequency band. As the curable compound for the substrate, epoxy compounds, maleimide compounds, and the radically polymerizable compounds described below are preferred. A resin composition containing a resin having a polymerizable group and / or a polymerizable compound as the substrate together with a resin modifier is a curable composition. Such a curable composition preferably contains a curing agent such as a radical polymerization initiator or a cationic polymerization initiator because it is easy to cure.

[0101] As the base material, polyphenylene ether is preferred because of its excellent dielectric properties in the high frequency band. The polyphenylene ether may be a polyphenylene ether resin having a number average molecular weight of 10,000 or more, or a modified polyphenylene ether oligomer having a number average molecular weight of less than 10,000. The polyphenylene ether is preferably a modified polyphenylene ether having a carbon-carbon unsaturated double bond-containing group. Such a modified polyphenylene ether may be a modified polyphenylene ether resin having a number average molecular weight of 10,000 or more, or a modified polyphenylene ether oligomer having a number average molecular weight of less than 10,000. The modified polyphenylene ether oligomer having a number average molecular weight of less than 10,000 corresponds to a curable compound in that it has a carbon-carbon unsaturated double bond-containing group.

[0102] The modified polyphenylene ether preferably has a carbon-carbon unsaturated double bond-containing group bonded to an oxygen atom at the molecular chain terminal. The polyphenylene ether usually has a hydroxyl group bonded to an aromatic ring at the molecular chain terminal. The modified polyphenylene ether can be obtained by substituting the hydrogen atom in this terminal hydroxyl group with the carbon-carbon unsaturated double bond-containing group.

[0103] The carbon-carbon unsaturated double bond-containing group is preferably one or more selected from a vinylbenzyl group, a vinyl group, an allyl group, and a (meth)acryloyl group. When the carbon-carbon unsaturated double bond-containing group is a vinylbenzyl group, an allyl group, or a (meth)acryloyl group, the terminal hydroxyl groups of the polyphenylene ether can be converted to vinylbenzyloxy groups, allyloxy groups, or (meth)acryloyloxy groups using a corresponding halide according to a conventional method. When the carbon-carbon unsaturated double bond-containing group is a vinyl group, the terminal hydroxyl groups of the polyphenylene ether can be converted to vinyloxy groups by methods such as an ether exchange reaction between a vinyl ether compound, such as an alkyl vinyl ether (e.g., methyl vinyl ether), and the terminal hydroxyl groups; a vinylation reaction using a vinyl ester compound (e.g., vinyl acetate); or the addition of acetylene to the terminal hydroxyl groups.

[0104] Commercially available products can also be used as the modified polyphenylene ether having a carbon-carbon unsaturated double bond-containing group bonded to an oxygen atom at the molecular chain terminal. Specific examples of commercially available products include vinylbenzyl-terminated polyphenylene ethers such as OPE-2St-2200 and OPE-2st-1200 (both manufactured by Mitsubishi Gas Chemical Company, Inc.) and methacryloyl-terminated polyphenylene ethers such as Noryl (registered trademark) SA9000 (manufactured by SABIC).

[0105] The molecular weight of the modified polyphenylene ether is not particularly limited as long as the desired effect is not impaired. The molecular weight of the modified polyphenylene ether is preferably 1,000 or more, more preferably 2,000 or more, in terms of number average molecular weight (Mn).

[0106] The resin composition is also preferably a radically polymerizable composition. That is, the resin composition may contain, in addition to the resin modifier, a radically polymerizable compound as a base material and a radical polymerization initiator. The radically polymerizable composition may contain, as a base material, a combination of a resin and a radically polymerizable compound. The radically polymerizable compound may be a monofunctional compound having one radically polymerizable group or a polyfunctional compound having two or more radically polymerizable groups, with polyfunctional compounds being preferred. The radically polymerizable group is not particularly limited, but is typically a carbon-carbon double bond-containing group. Suitable examples of the carbon-carbon double bond-containing group include alkenyl groups such as vinyl groups, allyl groups, and methallyl groups, unsaturated acyl groups such as acryloyl groups and methacryloyl groups, and maleimide groups.

[0107] Specific preferred examples of the radical polymerizable compound include triallyl cyanurate, triallyl isocyanurate, trimethallyl isocyanurate, trimethylolpropane tri(meth)acrylate, 1,3,5-triacryloylhexahydro-1,3,5-triazine, triallyl trimellitate, 1,3-phenylenediamine bismaleimide, p-quinonedioxime, p,p'-dibenzoylquinonedioxime, dipropargyl terephthalate, diallyl phthalate, and N,N',N'',N'''-tetraallyl terephthalamide. Note that "(meth)acrylate" refers to both acrylate and methacrylate.

[0108] Among these, at least one selected from the group consisting of triallyl cyanurate, triallyl isocyanurate, trimethallyl isocyanurate, and trimethylolpropane tri(meth)acrylate is more preferred.

[0109] When the resin composition contains a radically polymerizable compound as a base material, the content of the radically polymerizable compound in the resin composition is preferably 20% by mass or more and 100% by mass or less, and more preferably 30% by mass or more and 100% by mass or less, relative to the mass of the base material.

[0110] As the radical polymerization initiator, any conventionally known radical polymerization initiator can be used without any particular limitation. Specific examples of suitable radical polymerization initiators are the same as the specific examples of radical polymerization initiators that can be used when graft-modifying a styrene-based elastomer or a polyolefin-based resin. The above radical polymerization initiators can be used alone or in combination of two or more.

[0111] The amount of the radical polymerization initiator used is not particularly limited as long as the resin composition is radically polymerizable by heating or exposure to light. The amount of the radical polymerization initiator used is, for example, preferably 0.5 parts by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 10 parts by mass or less, and even more preferably 2 parts by mass or more and 8 parts by mass or less, relative to 100 parts by mass of the radical polymerizable compound.

[0112] When the resin composition is a radically polymerizable composition and contains a resin as a base material and a radically polymerizable compound, the base material resin is preferably modified by introducing a radically polymerizable group into the main chain. In this case, the resin is crosslinked by the radically polymerizable compound, and therefore, a cured product having excellent dielectric properties and mechanical strength can be formed using the resin composition.

[0113] The resin composition may contain an inorganic filler as needed. Examples of inorganic fillers include calcium carbonate, talc, clay, silica, magnesium carbonate, barium sulfate, titanium oxide, alumina, montmorillonite, gypsum, glass flakes, glass fiber, milled glass fiber, carbon fiber, alumina fiber, silica-alumina fiber, aluminum borate whisker, and potassium titanate fiber. The inorganic fillers may be used alone or in combination of two or more.

[0114] The amount of these inorganic fillers used is not particularly limited as long as the desired effects are not impaired. The amount of the base-free filler used is preferably 10 parts by mass or more and 200 parts by mass or less, and more preferably 20 parts by mass or more and 100 parts by mass or less, relative to 100 parts by mass of the base material.

[0115] The resin composition may further contain various additives, such as an organic filler, an antioxidant, a heat stabilizer, a light stabilizer, a flame retardant, a lubricant, an antistatic agent, a colorant, a rust inhibitor, a crosslinking agent, a foaming agent, a fluorescent agent, a surface smoothing agent, a surface gloss improving agent, and a mold release improving agent, as needed.

[0116] These additives may be used alone or in combination of two or more.

[0117] Regarding the resin composition described above, when the resin composition is a radically polymerizable composition, the resin composition is cured by applying energy to the resin composition by a method such as heating or exposure to light, and a cured product is formed.

[0118] As described above, the resin composition or a cured product of the resin composition is preferably used as a material for a wiring board. As a material for the wiring board, a sheet made of the resin composition or a prepreg made of a fiber sheet and a cured product of the resin composition composited with the fiber sheet is preferred. The method for forming a sheet made of the resin composition is not particularly limited. When the resin composition is a varnish-like composition, a sheet made of the resin composition can be formed by a solution casting method. The above prepreg can also be formed by impregnating a fiber sheet such as a glass fiber sheet with a radically polymerizable resin composition, and then curing the resin composition impregnated into the fiber sheet by a method such as heating or exposure to light.

[0119] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0120] [Production Example A1-1] (Production of Modified Styrenic Elastomer A1-1) 100 parts by mass of styrene / ethylene butylene / styrene elastomer (SEPTON 8007L, manufactured by Kuraray) and 0.15 parts by mass of 1,3-di(tert-butylperoxyisopropyl)benzene (PERBUTYL P, manufactured by NOF Corp.) were supplied from the hopper port to a twin-screw extruder (46 mmφ, L / D=63, manufactured by Kobe Steel, Ltd., KTX46) set at a cylinder temperature of 230°C and a screw rotation speed of 150 rpm, and melt-kneaded. 1 part by mass of styrene and 1 part by mass of glycidyl methacrylate were added midway through the cylinder. Subsequently, pellets of modified styrenic elastomer A1-1 were obtained by vacuum devolatilization through a vent port.

[0121] The obtained resin pellets were dissolved in xylene at 130°C and then cooled to room temperature again to precipitate a recrystallized resin, which was used to measure the epoxy group content using an automatic potentiometric titrator (AT700 manufactured by Kyoto Electronics Manufacturing Co., Ltd.) in accordance with JIS K 7236. The epoxy group content of the modified styrene-based elastomer A1-1 was 0.21% by mass.

[0122] [Production Example A1-2] (Production of Modified Styrenic Elastomer A1-2) A modified styrene-based elastomer A1-2 was obtained in the same manner as in Production Example A1-1, except that SEPTON 8007L was replaced with a styrene / isobutylene / styrene elastomer (SIBSTAR 103T, manufactured by Kaneka). The epoxy group content of the modified styrene-based elastomer A1-2 was 0.34 mass%.

[0123] [Production Example B1] 200 parts by mass of water, 0.03 parts by mass of tripotassium phosphate, 0.25 parts by mass of potassium dihydrogen phosphate, 0.002 parts by mass of ethylenediaminetetraacetic acid (EDTA), 0.001 parts by mass of ferrous sulfate heptahydrate, and 1.5 parts by mass of sodium dodecylbenzenesulfonate (SDBS) were added to a 100 L pressure polymerization vessel. While stirring the mixture in the pressure polymerization vessel, oxygen in the vessel was thoroughly removed by nitrogen substitution. Subsequently, 75 parts by mass of butadiene (Bd) and 25 parts by mass of styrene were added to the pressure polymerization vessel. Next, the temperature in the pressure polymerization vessel was raised to 45°C. Subsequently, 0.015 parts by mass of paramenthane hydroperoxide (PHP) was added to the pressure polymerization vessel. Next, 0.04 parts by mass of sodium formaldehyde sulfoxylate (SFS) was added to the pressure polymerization vessel to initiate polymerization. Four hours after the start of polymerization, 0.01 parts by mass of PHP, 0.0015 parts by mass of EDTA, and 0.001 parts by mass of ferrous sulfate heptahydrate were added to the pressure-resistant polymerization vessel. Ten hours after the start of polymerization, the reaction solution in the pressure-resistant polymerization vessel was depressurized to remove volatile components such as remaining monomers, thereby terminating the polymerization. In this manner, a styrene-butadiene rubber latex was obtained. The volume-average particle size of the styrene-butadiene rubber particles contained in the obtained styrene-butadiene rubber latex was 100 nm.

[0124] 241 parts by mass of the obtained styrene-butadiene rubber latex (80 parts by mass of styrene-butadiene rubber particles) and 65 parts by mass of water were added to a glass reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, a nitrogen inlet, and a monomer addition device. The gas in the glass reaction vessel was replaced with nitrogen. The contents of the glass reaction vessel were then stirred at 60°C. 0.004 parts by mass of EDTA, 0.001 parts by mass of ferrous sulfate heptahydrate, and 0.2 parts by mass of SFS were then added to the glass reaction vessel. 2 parts by mass of triallyl isocyanurate (TAIC) and 0.07 parts by mass of cumene hydroperoxide (CHP) were then added to the glass reaction vessel. The contents of the glass reaction vessel were then stirred for 60 minutes. Thereafter, a mixture of 12 parts by mass of styrene, 4 parts by weight of acrylonitrile, 4 parts by mass of glycidyl methacrylate, and 0.08 parts by mass of tert-butyl hydroperoxide (TBP) was continuously added to a glass reaction vessel over a period of 110 minutes. Thereafter, 0.04 parts by mass of TBP was added to the glass reaction vessel, and stirring was continued for another hour to complete the polymerization. In this way, an aqueous latex containing core-shell polymer particles B1 was obtained. The volume average particle diameter of the core-shell polymer particles B1 contained in the aqueous latex was 110 nm. Furthermore, the ratio of the mass of epoxy groups to the mass of the core-shell polymer particles B1 was 1.2% by mass. Using the obtained aqueous latex, a dispersion of core-shell polymer B1 was obtained in which the core-shell polymer particles B1 were dispersed in methyl ethyl ketone (MEK) at a solids concentration of 25% by mass, according to the method described in Production Example 1 of WO 2020 / 027189.

[0125] Example 1-1: 7.2 g of the modified styrene-based elastomer A1-1 obtained in Production Example A1-1 was dissolved in 28.8 g of toluene. Next, 11.2 g of a methyl ethyl ketone (MEK) dispersion of core-shell polymer particles B1 (solids concentration: 25% by mass) was added to the toluene solution of the modified styrene-based elastomer A1-1 to obtain 47.2 g of Modifier 1-1. The obtained 47.2 g of Modifier 1-1 contained 2.8 g of core-shell polymer particles B1.

[0126] Example 1-2 46.0 g of Modifier 1-2 was obtained in the same manner as in Example 1-1, except that the amount of modified styrene-based elastomer A1-1 was changed from 7.2 g to 4.0 g, the amount of toluene was changed from 28.8 g to 18.0 g, and the amount of MEK dispersion of core-shell polymer particles B1 was changed from 11.2 g to 24.0 g. The obtained 46.0 g of Modifier 1-2 contained 6.0 g of core-shell polymer particles B1.

[0127] Example 1-3 56.6 g of Modifier 1-3 was obtained in the same manner as in Example 1-1, except that the amount of modified styrene-based elastomer particles A1-1 was changed from 7.2 g to 7.0 g, the amount of toluene was changed from 28.8 g to 28.0 g, and the amount of dispersion of core-shell polymer particles B1 was changed from 11.2 g to 21.6 g. The obtained 56.6 g of Modifier 1-3 contained 5.4 g of core-shell polymer particles B1.

[0128] Example 1-4: 47.2 g of Modifier 1-4 was obtained in the same manner as in Example 1-1, except that 7.2 g of Modified Styrenic Elastomer A1-1 was changed to 7.2 g of Modified Styrenic Elastomer A1-2. The obtained 47.2 g of Modifier 1-4 contained 2.8 g of core-shell polymer particles B1.

[0129] Example 1-5: 56.6 g of Modifier 1-5 was obtained in the same manner as in Example 1-3, except that 7.0 g of Modified Styrenic Elastomer A1-1 was changed to 7.0 g of Modified Styrenic Elastomer A1-2. The obtained 56.6 g of Modifier 1-5 contained 5.4 g of core-shell polymer particles B1.

[0130] Example 1-6 55.1 g of Modifier 1-6 was obtained in the same manner as in Example 1-1, except that the amount of modified styrene-based elastomer A1-1 used was changed from 7.2 g to 9.9 g, the amount of toluene used was changed from 28.8 g to 39.6 g, and the amount of MEK dispersion of core-shell polymer particles B1 used was changed from 11.2 g to 5.6 g. The obtained 55.1 g of Modifier 1-6 contained 1.4 g of core-shell polymer particles B1.

[0131] Example 1-7 74.2 g of Modifier 1-7 was obtained in the same manner as in Example 1-1, except that the amount of modified styrene-based elastomer A1-1 used was changed from 7.2 g to 13.8 g, the amount of toluene used was changed from 28.8 g to 55.2 g, and the amount of MEK dispersion of core-shell polymer particles B1 used was changed from 11.2 g to 5.2 g. The obtained 74.2 g of Modifier 1-7 contained 1.3 g of core-shell polymer particles B1.

[0132] Example 1-8: 55.1 g of Modifier 1-8 was obtained in the same manner as in Example 1-6, except that 9.9 g of Modified Styrenic Elastomer A1-1 was changed to 9.9 g of Modified Styrenic Elastomer A1-2. The obtained 55.1 g of Modifier 1-8 contained 1.4 g of core-shell polymer particles B1.

[0133] Example 1-9: 74.2 g of Modifier 1-9 was obtained in the same manner as in Example 1-7, except that 13.8 g of Modified Styrenic Elastomer A1-1 was changed to 13.8 g of Modified Styrenic Elastomer A1-2. The obtained 74.2 g of Modifier 1-9 contained 1.3 g of core-shell polymer particles B1.

[0134] Example 1-10 78.9 g of Modifier 1-10 was obtained in the same manner as in Example 1-9, except that the amount of modified styrene-based elastomer A1-2 used was changed from 13.8 g to 13.7 g, the amount of toluene used was changed from 55.2 g to 54.8 g, and the amount of MEK dispersion of core-shell polymer particles B1 used was changed from 11.2 g to 10.4 g. The obtained 78.9 g of Modifier 1-10 contained 2.6 g of core-shell polymer particles B1.

[0135] Example 1-11 1.22 g of Modifier 1-11 was obtained in the same manner as in Example 1-1, except that the amount of modified styrene-based elastomer A1-1 used was changed from 7.2 g to 0.18 g, the amount of toluene used was changed from 28.8 g to 0.72 g, and the amount of MEK dispersion of core-shell polymer particles B1 used was changed from 11.2 g to 0.32 g. The obtained 1.22 g of Modifier 1-11 contained 0.08 g of core-shell polymer particles B1.

[0136] Example 12 9.9 g of Modifier 1-12 was obtained in the same manner as in Example 1-1, except that the amount of modified styrene-based elastomer A1-1 used was changed from 7.2 g to 1.9 g, the amount of toluene used was changed from 28.8 g to 7.6 g, and the amount of MEK dispersion of core-shell polymer particles B1 used was changed from 11.2 g to 0.4 g. The obtained 9.9 g of Modifier 1-12 contained 0.1 g of core-shell polymer particles B1.

[0137] Resin compositions were prepared by mixing the modifiers obtained in Examples 1-1 to 1-12 with polyphenylene ether modified at both ends with methacrylate. Specifically, the amount of polyphenylene ether (PPE) (manufactured by SABIC Corporation, trade name: Noryl (registered trademark) SA9000 resin, number average molecular weight: 1700) listed in Table 1, the amount of radical polymerizable compound (manufactured by Mitsubishi Chemical Corporation, triallyl isocyanurate (TAIC)) listed in Table 1, the amount of silica (manufactured by Admatechs Co., Ltd., trade name: SC2300-SVJ, average particle size 0.5 μm) listed in Table 1, and 1.1 g of initiator (manufactured by NOF Corporation, trade name: Perbutyl P (PBP)) were dissolved and dispersed in the amount of toluene listed in Table 1 to obtain a toluene dispersion. The modifier of each example was added to the toluene dispersion and stirred uniformly to obtain a resin composition containing the modifier of each example.

[0138] Using the obtained resin composition, a prepreg was obtained according to the following method. Specifically, a glass cloth (manufactured by Nitto Boseki Co., Ltd., product name: NE-1078, size: 100 mm x 200 mm) was impregnated with the resin composition of each example. The glass cloth impregnated with the resin composition was passed through two Teflon rods arranged in parallel with a 0.4 mm gap between them to remove excess resin composition. The glass cloth impregnated with the resin composition was heated at 60°C for 100 minutes, 100°C for 10 minutes, and 120°C for 50 minutes in this order to obtain a prepreg.

[0139] [Comparative Example 1-1] Each of the components shown in Table 1 was added to 100.0 g of toluene in the amount shown in Table 1. Each of the components shown in Table 1 was dissolved and dispersed in toluene to obtain a resin composition. Using the obtained resin composition, a prepreg was obtained in the same manner as in Example 1-1.

[0140] Comparative Example 1-2 12.0 g of a dispersion (solid content concentration 25% by mass) of the core-shell polymer particles B1 obtained in Production Example B1 dispersed in methyl ethyl ketone (MEK) and the respective components shown in Table 1 were added to 85.8 g of toluene. The core-shell polymer particles B1 and the respective components shown in Table 1 were dissolved and dispersed in toluene to obtain a resin composition. A prepreg was obtained using the obtained resin composition in the same manner as in Example 1-1.

[0141] [Comparative Example 1-3] To 85.8 g of toluene, 7.4 g of modified styrene-based elastomer A1-1 and the respective components shown in Table 1 were added in the amounts shown in Table 1. The modified styrene-based elastomer A1-1 and the respective components shown in Table 1 were dissolved and dispersed in toluene to obtain a resin composition. Using the obtained resin composition, a prepreg was obtained in the same manner as in Example 1-1.

[0142] [Measurement of Dielectric Loss Tangent (Df)] Cured sheets were formed using the prepregs obtained in each Example and Comparative Example, and the dielectric loss tangent was measured using test pieces cut out from the cured sheets. The specific method is described below. The measurement results of the dielectric loss tangent are shown in Table 1.

[0143] <Preparation of Cured Sheet> Cured sheets were prepared using the prepregs obtained in each Example and Comparative Example according to the following method. First, the prepreg was sandwiched between two Teflon sheets (manufactured by Nitto Denko Corporation, product name: Nitoflon (registered trademark), thickness 50 μm). The prepreg sandwiched between the two Teflon sheets was set in a press at a press temperature of 100°C and a press pressure of 0.5 MPa (G), and then the press temperature was increased at a rate of 3°C / min. When the press temperature reached 140°C, the press pressure was increased to 3.0 MPa (G). Next, the press temperature was increased to 200°C at a rate of 3°C / min. After the press temperature reached 200°C, pressing was continued for 75 minutes to obtain a cured sheet in which the cured resin composition and the glass sheet were combined.

[0144] <Measurement of dielectric loss tangent> Dielectric loss tangent was measured using a network analyzer (manufactured by KEYSIGHT Corporation) as a measuring device. A 30 mm x 40 mm test piece cut out from the cured sheet was used for measuring the dielectric loss tangent. Before measuring the dielectric loss tangent, the test piece was left to stand for 24 hours under conditions of 23°C and 50% RH. The measurement conditions were as follows: Measurement frequency: 40 GHz, Temperature: 23°C, Humidity: 50% RH

[0145] [Evaluation of Adhesion of Electrodeposited Copper Foil] Using the prepregs obtained in each Example and Comparative Example, metal laminates were formed in which electrolytic copper foils were laminated on both sides of a cured sheet of cured prepreg. The peel strength of the metal foil was measured using the obtained metal laminate. The specific method is described below. The peel strength measurement results are shown in Table 1.

[0146] <Preparation of Metal Laminate> A metal laminate was prepared using the prepreg obtained in each Example and Comparative Example according to the following method. First, the prepreg was sandwiched between two sheets of electrolytic copper foil (manufactured by Fukuda Metal Foil and Powder Co., Ltd., product name: CF-T49A-DS-HD2-18, thickness 18 μm, surface roughness 0.5 μm). The prepreg sandwiched between the two sheets of electrolytic copper foil was set in a press at a press temperature of 100°C and a press pressure of 0.5 MPa (G), and then the press temperature was increased at a rate of 3°C / min. When the press temperature reached 140°C, the press pressure was increased to 3.0 MPa (G). Next, the press temperature was increased to 200°C at a rate of 3°C / min. After the press temperature reached 200°C, pressing was continued for 75 minutes to obtain a metal laminate. In the metal laminate, electrolytic copper foil was laminated on both main surfaces of a cured sheet formed by combining a cured resin composition and a glass sheet.

[0147] The peel strength of the electrolytic copper foil was measured using the obtained metal laminate in accordance with "6.5 Peel Strength" of JIS C6471. Specifically, a 1 mm wide metal foil portion was peeled at a peel angle of 90° and a peel rate of 100 mm / min. The load during peeling was measured, and the measured value of the load was taken as the peel strength. The measured values ​​of the peel strength are shown in Table 1.

[0148] In Table 1 below, component (A1) is a modified styrene-based elastomer (A1).

[0149] Table 1 shows that when the modifiers of Examples 1-1 to 1-12 are used, which contain a modified resin (A) containing a modified styrene-based elastomer (A1) that satisfies the above-mentioned specified conditions and core-shell polymer particles (B) that satisfy the above-mentioned specified conditions, by blending the modifier with a resin such as a modified polyphenylene ether or resin, a cured product with excellent adhesion to copper foil can be formed. On the other hand, Comparative Examples 1-1 to 1-3 show that when the resin is not modified with both the modified resin (A) and the core-shell polymer particles (B), the cured product formed using the resin composition has poor adhesion to copper foil. Furthermore, a comparison between Comparative Example 1-1 and Examples 1-1 to 1-12 shows that modifying the resin with a modifier that satisfies the above-mentioned specified conditions does not significantly impair the electrical properties (dielectric loss tangent).

[0150] [Production Example A2-1] (Production of Modified Polyolefin Resin A2-1) 100 parts by mass of an α-olefin copolymer having a polymethylpentene structure (Absortomer EP1013 manufactured by Mitsui Chemicals) and 0.15 parts by mass of 1,3-di(tert-butylperoxyisopropyl)benzene (Perbutyl P manufactured by NOF Corp.) were supplied from a hopper port to a twin-screw extruder (46 mmφ, L / D=63, manufactured by Kobe Steel, Ltd., KTX46) set at a cylinder temperature of 200°C and a screw rotation speed of 150 rpm, and melt-kneaded. 1 part by mass of styrene and 1 part by mass of glycidyl methacrylate were then added midway through the cylinder. Subsequently, pellets of modified polyolefin resin A2-1 were obtained by vacuum devolatilization through a vent port.

[0151] The obtained resin pellets were dissolved in xylene at 130°C, and then cooled to room temperature again to precipitate a recrystallized resin. The epoxy group content of the recrystallized resin was measured using an automatic potentiometric titrator (AT700 manufactured by Kyoto Electronics Manufacturing Co., Ltd.) in accordance with JIS K 7236. The epoxy group content of the modified polyolefin resin A2-1 was 0.23% by mass.

[0152] [Production Example A2-2] (Production of Modified Polyolefin Resin A2-2) Modified polyolefin resin A2-2 was obtained in the same manner as in Production Example A2-1, except that the amount of 1,3-di(tert-butylperoxyisopropyl)benzene (Perbutyl P, manufactured by NOF Corp.) used was changed to 0.5 parts by mass, the amount of styrene used was changed to 2 parts by mass, and the amount of glycidyl methacrylate used was changed to 2 parts by mass. The epoxy group content of modified polyolefin resin A2-2 was 0.73% by mass.

[0153] [Production Example A2-3] (Production of Modified Polyolefin Resin A2-3) Modified polyolefin resin A2-3 was obtained in the same manner as in Production Example A2-1, except that the amount of 1,3-di(tert-butylperoxyisopropyl)benzene (Perbutyl P, manufactured by NOF Corp.) used was changed to 1.5 parts by mass, the amount of styrene used was changed to 8 parts by mass, and the amount of glycidyl methacrylate used was changed to 8 parts by mass. The epoxy group content of modified polyolefin resin A2-3 was 2.95% by mass.

[0154] Example 2-1 6.8 g of the modified polyolefin resin A2-1 obtained in Production Example A2-1 and 4.8 g of a compatibilizer (product name: 8903P, styrene / ethylene butylene / styrene elastomer (SEBS), manufactured by ENEOS Materials Corporation) were dissolved in 34.8 g of toluene. Next, 10.4 g of a methyl ethyl ketone (MEK) dispersion (solids concentration 25% by mass) of the core-shell polymer particles B1 obtained in Production Example B1 was added to the toluene solution of the modified polyolefin resin A2-1 to obtain 56.8 g of modifier 2-1. The obtained 56.8 g of modifier 2-1 contained 2.6 g of core-shell polymer particles B1.

[0155] Example 2-2 94.8 g of Modifier 2-2 was obtained in the same manner as in Example 2-1, except that the amount of modified polyolefin resin A2-1 used was changed from 6.8 g to 13.7 g, the amount of toluene used was changed from 34.8 g to 55.5 g, and the amount of MEK dispersion of core-shell polymer B1 used was changed from 10.4 g to 20.8 g. The obtained 94.8 g of Modifier 2-2 contained 5.2 g of core-shell polymer particles B1.

[0156] Example 2-3 56.8 g of Modifier 2-3 was obtained in the same manner as in Example 2-1, except that 6.8 g of Modified Polyolefin Resin A2-1 was changed to 7.6 g of Modified Polyolefin Resin A2-2, the amount of toluene used was changed from 34.8 g to 37.2 g, and the amount of MEK dispersion of Core-Shell Polymer B1 used was changed from 10.4 g to 7.2 g. The obtained 56.8 g of Modifier 2-3 contained 1.8 g of core-shell polymer particles B1.

[0157] Example 2-4: 56.8 g of Modifier 2-4 was obtained in the same manner as in Example 2-1, except that Modified Polyolefin Resin A2-1 was replaced with Modified Polyolefin Resin A2-3. The obtained 56.8 g of Modifier 2-4 contained 2.6 g of core-shell polymer particles B1.

[0158] A resin composition was prepared by mixing the modifier obtained in Examples 2-1 to 2-4 with polyphenylene ether modified at both ends with methacrylate. Specifically, the amount of polyphenylene ether (PPE) (manufactured by SABIC Corporation, trade name: Noryl (registered trademark) SA9000 resin, number average molecular weight: 1700) listed in Table 2, the amount of radical polymerizable compound (manufactured by Mitsubishi Chemical Corporation, triallyl isocyanurate (TAIC)) listed in Table 2, the amount of silica (manufactured by Admatechs Co., Ltd., trade name: SC2300-SVJ, average particle size 0.5 μm) listed in Table 1, and 1.1 g of initiator (manufactured by NOF Corporation, trade name: Perbutyl P (PBP)) were dissolved and dispersed in the amount of toluene listed in Table 2 to obtain a toluene dispersion. The modifier of each example was added to the toluene dispersion and stirred uniformly to obtain a resin composition containing the modifier of each example.

[0159] Using the obtained resin composition, a prepreg was obtained according to the following method. Specifically, a glass cloth (manufactured by Nitto Boseki Co., Ltd., product name: NE-1078, size: 100 mm x 200 mm) was impregnated with the resin composition of each example. The glass cloth impregnated with the resin composition was passed through two Teflon rods arranged in parallel with a 0.4 mm gap between them to remove excess resin composition. The glass cloth impregnated with the resin composition was heated at 60°C for 100 minutes, 100°C for 10 minutes, and 120°C for 50 minutes in this order to obtain a prepreg.

[0160] [Comparative Example 2-1] To 100.0 g of toluene, each of the components shown in Table 2 was added in the amount shown in Table 2. Each of the components shown in Table 2 was dissolved and dispersed in toluene to obtain a resin composition. Using the obtained resin composition, a prepreg was obtained in the same manner as in Example 2-1.

[0161] Comparative Example 2-2 12.0 g of a dispersion (solid content concentration 25% by mass) of the core-shell polymer particles B1 obtained in Production Example B1 dispersed in methyl ethyl ketone (MEK) and the respective components shown in Table 2 were added to 85.8 g of toluene. The core-shell polymer particles B1 and the respective components shown in Table 2 were dissolved and dispersed in toluene to obtain a resin composition. A prepreg was obtained using the obtained resin composition in the same manner as in Example 2-1.

[0162] Comparative Example 2-3 7.0 g of the modified polyolefin resin A2-1 obtained in Production Example A2-1 and 4.9 g of a compatibilizer (product name: 8903P, styrene / ethylene butylene / styrene elastomer (SEBS), manufactured by ENEOS Materials Corporation) were dissolved in 27.2 g of toluene to obtain Modifier 2-5. The obtained Modifier 2-5 and the components listed in Table 2 were added to 85.8 g of toluene in the amounts listed in Table 2. The modified polyolefin resin A2-1, the compatibilizer, and the components listed in Table 2 were dissolved and dispersed in toluene to obtain a resin composition. A prepreg was obtained using the obtained resin composition in the same manner as in Example 2-1.

[0163] Comparative Example 2-4 6.8 g of the modified polyolefin resin A2-1 obtained in Production Example A2-1 and 4.8 g of a compatibilizer (product name: 8903P, styrene / ethylene butylene / styrene elastomer (SEBS), manufactured by ENEOS Materials Corporation) were dissolved in 42.6 g of toluene. Next, 2.6 g of core-shell polymer particles B2 (butadiene-based rubber type, manufactured by Kaneka Corporation, Kane Ace (registered trademark) M-732) without polar groups were added to the toluene solution of the modified polyolefin resin to obtain Modifier 2-6. The obtained Modifier 2-6 and the respective components listed in Table 2 were added to 85.8 g of toluene in the amounts listed in Table 2. The modified polyolefin resin A2-1, the compatibilizer, and the respective components listed in Table 2 were dissolved and dispersed in toluene to obtain a resin composition. Using the obtained resin composition, a prepreg was obtained in the same manner as in Example 2-1.

[0164] Using the prepregs obtained in Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-4, the dielectric loss tangent (Df) was measured and the adhesion of the electrolytic copper foil was evaluated in the same manner as in Examples 1-1 to 11 and Comparative Examples 1-1 to 1-3. The measurement results and evaluation results are shown in Table 2.

[0165]

[0166] Table 2 shows that when the modifiers of Examples 2-1 to 2-4 containing a modified resin (A) containing a modified polyolefin resin (A2) that satisfies the above-mentioned specified conditions and core-shell polymer particles (B) that satisfy the above-mentioned specified conditions are used, it is possible to form a cured product with excellent adhesion to copper foil by blending the modifier with a resin such as a polyphenylene ether resin. On the other hand, Comparative Examples 2-1 to 2-4 show that when the resin is not modified using both the modified resin (A) containing the modified polyolefin resin (A2) and the core-shell polymer particles (B), or when the modified resin (A) or the core-shell polymer particles (B) do not have polar groups, the cured product formed using the resin composition has poor adhesion to copper foil. Furthermore, a comparison between Comparative Example 2-1 and Examples 2-1 to 2-4 shows that the electrical properties (dielectric loss tangent) are not significantly impaired even when the resin is modified with a modifier that satisfies the above-mentioned specified conditions.

Claims

1. It comprises a modified resin (A) and core-shell polymer particles (B), The modified resin (A) includes a modified styrene elastomer (A1), The modified resin (A) and the core-shell polymer particles (B) are modified with monomers having one or more polar groups selected from the group consisting of epoxy groups, amino groups, acid anhydride groups, hydroxyl groups, and carboxyl groups, and an ethylenically unsaturated bond. A resin modifier wherein the type of polar group that is most abundant among one or more types of polar groups in the modified resin (A) is the same as the type of polar group that is most abundant among one or more types of polar groups in the core-shell polymer particles (B).

2. A modified resin (A), core-shell polymer particles (B), and styrene-based elastomer (C) The modified resin (A) includes a modified polyolefin resin (A2), The modified resin (A) and the core-shell polymer particles (B) are modified with monomers having one or more polar groups selected from the group consisting of epoxy groups, amino groups, acid anhydride groups, hydroxyl groups, and carboxyl groups, and an ethylenically unsaturated bond. A resin modifier wherein the type of polar group that is most abundant among one or more types of polar groups in the modified resin (A) is the same as the type of polar group that is most abundant among one or more types of polar groups in the core-shell polymer particles (B).

3. The resin modifier according to claim 1 or 2, wherein the most abundant of the one or more polar groups present in the modified resin (A), and the most abundant of the one or more polar groups present in the core-shell polymer particles (B), are epoxy groups.

4. The resin modifier according to claim 1 or 2, wherein the content of the polar group in the modified resin (A) is 0.1% by mass or more and 8% by mass or less based on the mass of the modified resin (A).

5. The resin modifier according to claim 1 or 2, wherein the content of the polar group in the core-shell polymer particles (B) is 0.5% by mass or more and 10% by mass or less, relative to the mass of the core-shell polymer particles (B).

6. The modified resin (A) includes the modified styrene elastomer (A1), The resin modifier according to claim 1, comprising 25 to 98 parts by mass of the modified resin (A) and 2 to 75 parts by mass of the core-shell polymer particles (B) per 100 parts by mass of the resin modifier.

7. The modified resin (A) includes the modified polyolefin resin (A2), The ratio of the mass of the modified resin (A) to the total mass of the core-shell polymer particles (B) is 25% by mass or more and 90% by mass or less. The resin modifier according to claim 2, wherein the ratio of the mass of the core-shell polymer particles (B) to the sum of the mass of the modified resin (A) and the mass of the core-shell polymer particles (B) is 10% by mass or more and 75% by mass or less.

8. The resin modifier according to claim 2, wherein the ratio of the mass of the styrene-based elastomer (C) to the sum of the mass of the modified resin (A) and the mass of the core-shell polymer particles (B) is 20% by mass or more and 70% by mass or less.

9. The resin modifier according to claim 2, wherein the styrene-based elastomer (C) comprises at least one selected from the group consisting of styrene / isoprene / styrene elastomer, styrene / isobutylene / styrene elastomer, styrene / ethylenebutylene / styrene elastomer, hydrogenated styrene / isoprene / styrene elastomer, and hydrogenated styrene / (butadiene / isoprene) / styrene elastomer.

10. The material comprises one or more substrates selected from resins and curable compounds, and the resin modifier according to claim 1 or 2. When the modified resin (A) contains the modified styrene elastomer (A1), the total mass of the modified resin (A) and the mass of the core-shell polymer particles (B) is 0.1 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the substrate. A resin composition in which, when the modified resin (A) contains the modified polyolefin resin (A2), the total mass of the modified resin (A) and the mass of the core-shell polymer particles (B) is 5 parts by mass or more and 80 parts by mass or less per 100 parts by mass of the substrate.

11. The resin composition according to claim 10, wherein the base material is polyphenylene ether.

12. Furthermore, it contains a radical polymerization initiator, The substrate includes a radical polymerizable compound as the curable compound, The resin composition according to claim 10, wherein the content of the radical polymerizable compound is 20% by mass or more and 100% by mass or less with respect to the mass of the base material.

13. A cured product of the resin composition according to claim 12.

14. A sheet made of the resin composition according to claim 10.

15. A prepreg comprising a fiber sheet and a cured product according to claim 13 which is compounded with the fiber sheet.