Resin composition, and prepreg, film with resin, metal foil with resin, metal-clad laminate, and wiring board each obtained using same

Abstract

One aspect of the present invention relates to a resin composition which comprises: a maleimide compound (A) that includes at least one compound selected from the group consisting of a maleimide compound (A1) that has an indane structure represented by formula (1) in each molecule, a maleimide compound (A2) that has an arylene structure oriented and bonded to the meta position in each molecule, and a maleimide compound (A3) that has the indane structure and an arylene structure oriented and bonded to the meta position in each molecule; a reaction product (B) that is obtained by subjecting a phenol, a diamine, and formaldehyde to a condensation reaction, and includes a benzoxazine compound (B1) that has a structure represented by formula (2); and a styrene polymer (C) that is in a solid state at 25°C.

Description

Resin composition, and prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates, and wiring boards using the same.

[0001] The present invention relates to a resin composition, and to prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates, and wiring boards using the same.

[0002] In recent years, with the increasing performance of electronic devices and the remarkable improvement in information and communication speeds, semiconductor package substrates used in network equipment, servers, and AI processors are becoming larger and denser as performance and integration advance. Therefore, there is a demand for low warping and high mounting reliability in substrates, and to achieve this, substrate materials are increasingly required to have low thermal expansion coefficients to ensure connection reliability such as low warping and narrow pitch.

[0003] From the viewpoint of ensuring low thermal expansion in the substrate, the use of maleimide resin as a substrate material has been reported (Patent Document 1, etc.). On the other hand, it has become clear that maleimide resin has the problem of being somewhat inferior in adhesion, and as a method to improve this adhesion problem while maintaining the low thermal expansion of maleimide resin, examples of combining it with benzoxazine having an allyl group have also been reported (Patent Document 2).

[0004] More specifically, Patent Document 1 discloses a resin composition containing a maleimide compound having an indan structure and a styrene-based polymer, while Patent Document 2 discloses a resin composition containing a maleimide compound, an allyl group-containing benzoxazine compound, and a high molecular weight component.

[0005] The resin compositions described in Patent Documents 1 and 2 have been confirmed to be excellent in low dielectric loss tangent, a requirement that has been increasing in recent years. However, these resin compositions are still insufficient in terms of ensuring lower thermal expansion, maintaining elastic modulus over a wide temperature range, and ensuring higher heat resistance, which are necessary for reducing substrate warpage as semiconductor packages continue to grow in size.

[0006] International Publication No. 2022 / 054864, Japanese Patent Publication No. 2020-158705

[0007] The present invention has been made in view of the above circumstances, and aims to provide a resin composition that has a low coefficient of thermal expansion, a high glass transition temperature (Tg), and heat resistance in the cured product, and that can maintain its elastic modulus over a wide temperature range. The present invention also aims to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board using the resin composition.

[0008] A resin composition according to one aspect of the present invention comprises: a maleimide compound (A) having at least one selected from the group consisting of a maleimide compound (A1) having an indan structure represented by the following formula (1) in its molecule, a maleimide compound (A2) having an arylene structure bonded in the molecule oriented at the meta position, and a maleimide compound (A3) having the indan structure and an arylene structure bonded in the molecule oriented at the meta position; a reaction product (B) obtained by a condensation reaction of phenols, diamines, and formaldehyde, comprising a benzoxazine compound (B1) having a structure represented by the following formula (2); and a styrene polymer (C) that is solid at 25°C. [In formula (1), Rb independently represents a C1-C10 alkyl group, a C1-C10 alkyloxy group, a C1-C10 alkylthio group, a C6-C10 aryl group, a C6-C10 aryloxy group, a C6-C10 arylthio group, a C3-C10 cycloalkyl group, a halogen atom, a hydroxyl group, or a mercapto group; r is 0-3.] [In formula (2), R １ and R ２ Each independently represents either a methyl group or an ethyl group, R ３ and R ４ Each of these independently represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, v and w are each independently 0 to 4, and the bond position of the benzoxazine ring or NH to the biphenyl group is at the 4,4' position or the 3,4' position.

[0009] Figure 1 is a schematic cross-sectional view showing the structure of a prepreg according to one embodiment of the present invention. Figure 2 is a schematic cross-sectional view showing the structure of a metal-clad laminate according to one embodiment of the present invention. Figure 3 is a schematic cross-sectional view showing the structure of a wiring board according to one embodiment of the present invention. Figure 4 is a schematic cross-sectional view showing the structure of a resin-coated metal foil according to one embodiment of the present invention. Figure 5 is a schematic cross-sectional view showing the structure of a resin-coated film according to one embodiment of the present invention.

[0010] (Resin Composition) A resin composition according to an embodiment of the present invention (hereinafter also simply referred to as the resin composition) comprises: a maleimide compound (A) having an indane structure represented by formula (1) in its molecule (A1), a maleimide compound (A2) having an arylene structure bonded in the molecule oriented at the meta position, and a maleimide compound (A3) having the indane structure and an arylene structure bonded in the molecule oriented at the meta position; a reaction product (B) obtained by condensing phenols, diamines, and formaldehyde, comprising a benzoxazine compound (B1) having a structure represented by the following formula (2); and a styrene polymer (C) that is solid at 25°C.

[0011] The resin composition of this embodiment comprises a maleimide compound (A), a reaction product (B), and a styrene-based polymer (C) that is solid at 25°C. As a result, the cured product of this resin composition exhibits a low coefficient of thermal expansion, a high Tg, and heat resistance, while maintaining its elastic modulus over a wide temperature range. Therefore, the resin composition of this embodiment is extremely useful for industrial applications. Furthermore, by using the resin composition, it is possible to provide prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates, and wiring boards with excellent properties.

[0012] The components of the resin composition according to this embodiment will be described in detail below. Note that the following embodiments are merely examples of the present invention and do not limit the technical scope of the present invention.

[0013] <Maleimide Compound (A)> The maleimide compound (A) that can be used in this embodiment includes at least one selected from the group consisting of a maleimide compound (A1) having an indane structure represented by the above formula (1) in its molecule, a maleimide compound (A2) having an arylene structure bonded in a meta orientation in its molecule, and a maleimide compound (A3) having the indane structure and an arylene structure bonded in a meta orientation in its molecule. By including such a maleimide compound (A), the resin composition of this embodiment can have a high Tg and a low coefficient of thermal expansion in its cured product, in addition to the excellent low dielectric properties that maleimide compounds are said to possess.

[0014] - Maleimide compound (A1) having an indane structure in its molecule The indane structure of maleimide compound (A1) is represented by the following formula (1).

[0015] In formula (1), each Rb is independent. That is, each Rb may be the same group or different groups. For example, when r is 2 or 3, the two or three Rb groups bonded to the same benzene ring may be the same group or different groups. Rb represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group (alkoxy group) having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group (thiol group). r represents 0 to 3.

[0016] The maleimide compound (A1) of this embodiment also has a maleimide group in its molecule. More specifically, the maleimide compound (A1) of this embodiment includes the maleimide compound (A1-a) having a structure represented by the following formula (3) in its molecule.

[0017] In formula (3), each Ra is independent. That is, each Ra may be the same group or a different group. For example, when q is 2 to 4, the 2 to 4 Ra groups bonded to the same benzene ring may be the same group or a different group. Ra represents a C1 to C10 alkyl group, a C1 to C10 alkyloxy group, a C1 to C10 alkylthio group, a C6 to C10 aryl group, a C6 to C10 aryloxy group, a C6 to C10 arylthio group, a C3 to C10 cycloalkyl group, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. Rb is the same as Rb in formula (1), and each independently represents a C1-C10 alkyl group, a C1-C10 alkyloxy group, a C1-C10 alkylthio group, a C6-C10 aryl group, a C6-C10 aryloxy group, a C6-C10 arylthio group, a C3-C10 cycloalkyl group, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. q represents 0-4. r represents 0-3. n represents 0.95-10.

[0018] r is the average value of the degree of substitution of Rb, and a smaller value is preferable, specifically, a value of 0 is preferable. That is, in the benzene ring to which Rb can be bonded, it is preferable that a hydrogen atom is bonded at the position where Rb can be bonded. Maleimide compounds (A1) with such r are easy to synthesize. This is thought to be because the steric hindrance is reduced and the electron density of the aromatic ring is increased. Furthermore, when r is 1 to 3, it is preferable that Rb is at least one selected from the group consisting of C1-C4 alkyl groups, C3-C6 cycloalkyl groups, and C6-C10 aryl groups. Furthermore, it is preferable that Ra is at least one selected from the group consisting of C1-C4 alkyl groups, C3-C6 cycloalkyl groups, and C6-C10 aryl groups. By using C1-C4 alkyl groups, C3-C6 cycloalkyl groups, and C6-C10 aryl groups, solubility in solvents is improved, and the decrease in the reactivity of the maleimide group can be suppressed, resulting in a suitable cured product. This is thought to be due to a decrease in planarity and crystallinity near the maleimide group.

[0019] The groups represented by Ra and Rb specifically include the following groups:

[0020] The C1-C10 alkyl group is not particularly limited, and examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0021] The alkyloxy group having 1 to 10 carbon atoms is not particularly limited, and examples include methyloxy group, ethyloxy group, propyloxy group, hexyloxy group, and decyloxy group.

[0022] The alkylthio group having 1 to 10 carbon atoms is not particularly limited, and examples include methylthio group, ethylthio group, propylthio group, hexylthio group, and decylthio group.

[0023] The aryl group having 6 to 10 carbon atoms is not particularly limited, and examples include a phenyl group and a naphthyl group.

[0024] The aryloxy group having 6 to 10 carbon atoms is not particularly limited, and examples thereof include a phenyloxy group and a naphthyloxy group.

[0025] The arylthio group having 6 to 10 carbon atoms is not particularly limited, and examples thereof include a phenylthio group and a naphthylthio group.

[0026] The cycloalkyl group having 3 to 10 carbon atoms is not particularly limited, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, and a cyclooctyl group.

[0027] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0028] q is the average value of the substitution degree of Ra, preferably 2 to 3, more preferably 2. Such a maleimide compound (A1) with q is easy to synthesize. This is considered to be due to the reduction of steric hindrance and the increase in the electron density of the aromatic ring, especially when q is 2.

[0029] n is the average value of the repeating number. As described above, it is 0.95 to 10, preferably 0.98 to 8, more preferably 1 to 7, and even more preferably 1.1 to 6. In the maleimide compound (A1) having the structure represented by the formula (1) in the molecule and the maleimide compound (A1-a) represented by the formula (3), the content of the maleimide compound with n being 0, which is the average value of the repeating number (degree of polymerization), is preferably 32% by mass or less based on the total amount of the maleimide compound (A).

[0030] The maleimide compound (A) preferably has a molecular weight distribution (Mw / Mn) obtained by GPC measurement of 1 to 4, more preferably 1.1 to 3.8, even more preferably 1.2 to 3.6, and particularly preferably 1.3 to 3.4. The molecular weight distribution is obtained by gel permeation chromatography (GPC) measurement.

[0031] The method for producing the maleimide compound (A1) is not particularly limited as long as the maleimide compound (A1) can be produced. As the maleimide compound (A1), a commercially available maleimide compound may be used.

[0032] - Maleimide compound (A2) having an arylene structure bonded in the meta-position in the molecule The maleimide compound (A2) is not particularly limited as long as it is a maleimide compound having an arylene structure bonded in the meta-position in the molecule. Examples of the arylene structure bonded in the meta-position include an arylene structure in which a structure containing a maleimide group is bonded in the meta-position (an arylene structure in which a structure containing a maleimide group is substituted in the meta-position). Examples of the arylene structure bonded in the meta-position include m-arylene groups such as an m-phenylene group and an m-naphthylene group, and more specifically, groups represented by the following formula (6) and the like.

[0033]

[0034] More specifically, examples of the maleimide compound (A2) include maleimide compounds (A2-a) represented by the following formula (4), and more specifically, maleimide compounds (A2-a-1) represented by formula (5) described later and the like.

[0035] In formula (4), Ar represents an arylene group bonded in the meta-position. R Ａ , R Ｂ , R Ｃ , and R Ｄ are each independent. That is, R Ａ , R Ｂ , R Ｃ , and R Ｄ may be the same group or different groups. Also, R Ａ , R Ｂ , R Ｃ , and R Ｄ represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and are preferably a hydrogen atom. R Ｅ and R ＦThey are independent of each other. That is, R Ｅ and R Ｆ This may be the same group or different groups. Also, R Ｅ and R Ｆ indicates an aliphatic hydrocarbon group. s represents 1 to 5.

[0036] The aforementioned arylene group is not particularly limited as long as it is an arylene group that is oriented and bonded to the meta position. Examples include m-arylene groups such as m-phenylene groups and m-naphthylene groups, and more specifically, the group represented by formula (6) above.

[0037] Examples of the C1-C5 alkyl group include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, and neopentyl group.

[0038] The aliphatic hydrocarbon group is a divalent group and may be acyclic or cyclic. Examples of the aliphatic hydrocarbon group include alkylene groups, and more specifically, methylene groups, methylmethylene groups, and dimethylmethylene groups. Among these, dimethylmethylene groups are preferred.

[0039] The maleimide compound (A2-a) represented by formula (4) is preferably such that the number of repeats, s, is 1 to 5. This s is the average value of the number of repeats (degree of polymerization).

[0040] In equation (5), s represents values ​​from 1 to 5. This s is the same as s in equation (4), and is the average value of the number of repeats (degree of polymerization).

[0041] The maleimide compound (A2-a) represented by formula (4) and the maleimide compound (A2-a-1) represented by formula (5) may include a monofunctional compound where s is 0, as long as the average value of the number of repeats (degree of polymerization), s, is between 1 and 5, and may also include polyfunctional compounds such as heptafunctional or octafunctional compounds where s is 6 or more.

[0042] As the maleimide compound (A2), a commercially available product may be used, for example, the solid content of MIR-5000-60T manufactured by Nippon Kayaku Co., Ltd.

[0043] Maleimide compound (A3) having an indane structure and an arylene structure bonded to the meta position in its molecule Maleimide compound (A3) is not particularly limited as long as it has an indane structure and an arylene structure bonded to the meta position in its molecule. Note that maleimide compound (A3) has not only an arylene structure and an indane structure, but also a maleimide group in its molecule. The indane structure of maleimide compound (A3) is the same as the indane structure in maleimide compound (A1), and the arylene structure of maleimide compound (A3) is the same as the arylene structure bonded to the meta position in maleimide compound (A2). Specifically, maleimide compounds represented by the following formulas (7) to (9) can be mentioned as maleimide compounds (A3).

[0044]

[0045] In equation (7), n represents a range of 0.95 to 10.

[0046]

[0047] In equation (8), n represents a range of 0.95 to 10.

[0048]

[0049] In equation (9), n represents a range of 0.95 to 10.

[0050] As the maleimide compound (A3), commercially available products can be used, for example, the solid content in NE-X-9470S manufactured by DIC Corporation.

[0051] As the maleimide compound (A), one of the maleimide compounds described above may be used alone, or two or more may be used in combination.

[0052] In the resin composition of this embodiment, the content of maleimide compound (A) is preferably 20 to 60% by mass relative to the total amount of maleimide compound (A), reaction product (B), and styrene polymer (C). This is considered to ensure that the above-mentioned effects (low dielectric properties, low thermal expansion coefficient, high Tg) are obtained more reliably. A more preferable content is 30 to 50% by mass.

[0053] (Reaction product (B)) The reaction product used in this embodiment is a reaction product obtained by condensing phenols, diamines, and formaldehyde, and is reaction product (B) which contains a benzoxazine compound (B1) having the structure represented by the following formula (2). The benzoxazine compound (B1) contained in reaction product (B) is not particularly limited as long as it is a benzoxazine compound having the structure represented by the following formula (2). In formula (2), R １ and R ２ Each of these independently represents either a methyl group or an ethyl group. ３ and R ４ Each independently represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms. v and w are each independently 0 to 4. The bond position of the benzoxazine ring or NH to the biphenyl group is at the 4,4' position or the 3,4' position.

[0054] By including such a reaction product (B), the resin composition of the present invention can provide heat resistance and a high Tg in its cured product, and maintain its elastic modulus over a wide temperature range.

[0055] The alkyl group and alkenyl group in formula (2) above are not particularly limited as long as they have the number of carbon atoms as described above. The preferred alkyl group is a methyl group and / or an ethyl group, and the preferred alkenyl group is an allyl group and / or a propenyl group, with an allyl group being more preferred.

[0056] v is R １ The average value of the degree of substitution is 0 to 4, preferably 1 to 2. Also, w is R ２ The average value of the degree of substitution is between 0 and 4, and preferably between 1 and 2.

[0057] The reaction product (B) can be produced, for example, by a condensation reaction between phenols, diamines, and formaldehyde. Alternatively, a commercially available product containing a benzoxazine compound can be used as the reaction product (B). Furthermore, the benzoxazine compound produced by the above method may contain compounds in which one of the benzoxazine rings remains unclosed.

[0058] Specifically, for example, a benzoxazine compound (B2) represented by the following formula (2)' may be included as a by-product in the reaction product (B). Note that in equation (2)', R １ and R ２ Each of these independently represents either a methyl group or an ethyl group. ３ and R ４ Each of these independently represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms. Each of v and w is independently 0 to 4, and the bond position of the benzoxazine ring or NH to the biphenyl group is at the 4,4' position or the 3,4' position.

[0059] Furthermore, in addition to the main product, the benzoxazine compound (B1), and the by-product, the benzoxazine compound (B2), as described above, the reaction product (B) may also include polymers of benzoxazine (including oligomers) and / or other by-products. Examples of other by-products include compounds obtained by the dehydration condensation of one molecule of diamine and three or four molecules of phenols via formaldehyde, and compounds obtained by the dehydration condensation of two molecules of diamine and three molecules of phenols via formaldehyde. These may have one or more benzoxazine rings, and some of the benzoxazine rings may be open rather than closed.

[0060] In the resin composition of this embodiment, the content of the reaction product (B) is preferably 5 to 50% by mass relative to the total of the maleimide compound (A), the reaction product (B), and the styrene polymer (C). This is considered to more reliably obtain the effects described above (low dielectric properties, high Tg, heat resistance, and high modulus over a wide range). A more preferable content is 10 to 40% by mass.

[0061] In reaction product (B), the content of benzoxazine compound (B1) is preferably such that the peak area of ​​benzoxazine compound (B1) accounts for 50-75% of the total peak area of ​​reaction product (B) as determined by high-performance liquid chromatography (HPLC) (however, if the reaction product contains a solvent, the total peak area excluding the solvent is 100%). Furthermore, if reaction product (B) contains benzoxazine compound (B2), its peak area is preferably 5-15%. Moreover, the combined peak area of ​​benzoxazine compound (B1) and benzoxazine compound (B2) is preferably 65-80%.

[0062] (Styrene polymer (C)) The styrene polymer (C) is not particularly limited as long as it is a styrene polymer that is solid at 25°C. Examples of styrene polymer (C) include styrene polymers that are solid at 25°C and can be used as a resin in resin compositions used to form insulating layers provided in metal-clad laminates and wiring boards, etc. The resin composition used to form insulating layers provided in metal-clad laminates and wiring boards, etc. may be a resin composition used to form resin layers provided in resin-coated films and resin-coated metal foils, etc., or a resin composition contained in a prepreg. It is believed that by including the styrene polymer (C), the resin composition of this embodiment can obtain an even lower coefficient of thermal expansion in its cured product.

[0063] The styrene-based polymer (C) is, for example, a polymer obtained by polymerizing monomers containing a styrene-based monomer, and may also be a styrene-based copolymer. For example, the styrene-based polymer (C) is a copolymer obtained by copolymerizing one or more of the styrene-based monomers with one or more other monomers copolymerizable with the styrene-based monomers. The styrene-based copolymer may be a random copolymer or a block copolymer, as long as it has a structure derived from the styrene-based monomer in its molecule, but a block copolymer is more preferable from the viewpoint of lowering the coefficient of thermal expansion. Examples of the block copolymer are a binary copolymer of a structure (repeating unit) derived from the styrene-based monomer and the copolymerizable other monomer (repeating unit), and a ternary copolymer of a structure (repeating unit) derived from the styrene-based monomer and the copolymerizable other monomer (repeating unit).

[0064] The styrene monomer is not particularly limited, but examples include styrene, styrene derivatives, styrene in which some of the hydrogen atoms of the benzene ring are substituted with alkyl groups, styrene in which some of the hydrogen atoms of the vinyl group are substituted with alkyl groups, vinyltoluene, α-methylstyrene, butylstyrene, dimethylstyrene, and isopropenyltoluene. The styrene monomer may be used individually or in combination of two or more.

[0065] Furthermore, the styrene polymer (C) preferably has ethylene structural units and butylene structural units in its molecule. The ethylene structural units are not particularly limited, but examples include structural units (repeating units) derived from other copolymerizable monomers that have an ethylene structure. The ethylene structural units are structures derived from the 1,4-bond of a conjugated diene monomer (conjugated dienes), and the atom or group bonded to the carbon of the -C-C-bond in the main chain is a hydrogen atom or a methyl group. Specific examples of the conjugated diene monomers include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-cyclohexadiene. Therefore, the ethylene structural units specifically include structural units having an ethylene structure among the structural units derived from the conjugated dienes, and more specifically, structural units having an ethylene structure (1,4-addition structural units) among the structural units (repeating units) derived from 1,3-butadiene.

[0066] The butylene structural unit is not particularly limited, but examples include structural units (repeating units) derived from other copolymerizable monomers that have a butylene structure. The butylene structural unit is at least one of a structure derived from a 1,2-bond of a conjugated diene monomer (conjugated dienes) and a structure derived from a 3,4-bond of a conjugated diene monomer (conjugated dienes), and at least one of the atoms or groups bonded to the carbon of the -C-C-bond of the main chain is a side chain having two or more carbon atoms. Therefore, the butylene structural unit specifically includes structural units derived from the conjugated dienes that have a butylene structure, and more specifically, structural units (repeating units) derived from 1,3-butadiene that have a butylene structure (at least one of a 1,2-addition structural unit and a 3,4-addition structural unit). The butylene structural unit may be, for example, a hydrogenated structural unit.

[0067] In styrene-based polymers (C), it is believed that a lower coefficient of thermal expansion is possible as the proportion of ethylene structural units or butylene structural units increases.

[0068] The styrene polymer (C) may contain structural units (repeating units) derived from other copolymerizable monomers other than the ethylene structural unit and the butylene structural unit. Such other copolymerizable monomers are not particularly limited, but examples include olefins such as α-pinene, β-pinene, and dipentene, and non-conjugated dienes such as 1,4-hexadiene and 3-methyl-1,4-hexadiene.

[0069] Examples of styrene polymers (C) include methylstyrene (ethylene / butylene) methylstyrene block copolymer, methylstyrene (ethylene-ethylene / propylene) methylstyrene block copolymer, styrene isoprene block copolymer, styrene isoprene styrene block copolymer, styrene (ethylene / butylene) styrene block copolymer, styrene (ethylene-ethylene / propylene) styrene block copolymer, styrene butadiene block copolymer, styrene isobutylene styrene block copolymer, styrene (butadiene / butylene) styrene block copolymer, methylstyrene (styrene / butadiene random copolymer block) methylstyrene copolymer, and styrene (styrene / butadiene random copolymer block) styrene copolymer.

[0070] It is more preferable that the styrene polymer (C) includes a hydrogenated styrene copolymer in which at least a portion of the styrene copolymer is hydrogenated. This has the advantage of resulting in a cured product with a lower coefficient of thermal expansion.

[0071] Furthermore, the styrene polymer (C) may include a styrene copolymer in which at least a portion of the styrene polymer has been acid-modified with maleic acid or the like. This improves compatibility with the maleimide compound (A) and suppresses separation during varnish production.

[0072] Examples of the hydrogenated styrene copolymer include hydrogenated styrene copolymers. More specifically, examples of the hydrogenated styrene copolymer include hydrogenated methylstyrene (ethylene / butylene) methylstyrene copolymer, hydrogenated methylstyrene (ethylene-ethylene / propylene) methylstyrene copolymer, hydrogenated styrene isoprene copolymer, hydrogenated styrene isoprene styrene copolymer, hydrogenated styrene (ethylene / butylene) styrene copolymer, and hydrogenated styrene (ethylene-ethylene / propylene) styrene copolymer, hydrogenated methylstyrene (styrene / butadiene random copolymer block) hydrogenated methylstyrene copolymer, and hydrogenated styrene (styrene / butadiene random copolymer block) styrene copolymer.

[0073] As the styrene polymer (C), the styrene polymers exemplified above may be used alone, or two or more may be used in combination.

[0074] The styrene polymer (C) preferably has a weight-average molecular weight of 10,000 to 300,000, and more preferably 10,000 to 200,000. In this specification, the weight-average molecular weight can be any value measured by a general molecular weight measurement method, specifically, a value measured using gel permeation chromatography (GPC).

[0075] As the styrene polymer (C), commercially available products may be used, for example, V9827, V9461, 2002, 7125F from Kuraray Co., Ltd.; FTR2140, FTR6125 from Mitsui Chemicals, Inc.; and H1221, H1251, H1041, H1043, H1517, M1913, S1609, S1613, C5025 from Asahi Kasei Corporation.

[0076] In the resin composition of this embodiment, the content of the styrene polymer (C) is preferably 15 to 50% by mass relative to the total of the maleimide compound (A), the reaction product (B), and the styrene polymer (C). This is considered to more reliably obtain the above-mentioned effect (low thermal expansion coefficient). A more preferable content is 15 to 50% by mass.

[0077] (Other Organic Components) The resin composition of this embodiment may further contain organic components other than the maleimide compound (A), the reaction product (B), and the styrene polymer (C), as needed, to the extent that the effects of the present invention are not impaired. Examples of such organic components include a maleimide compound (D) different from the maleimide compound (A), a benzoxazine compound (E) different from the benzoxazine compound contained in the reaction product (B), epoxy compounds, methacrylate compounds, acrylate compounds, vinyl compounds, cyanate ester compounds, activated ester compounds, and allyl compounds.

[0078] Maleimide compound (D) is a maleimide compound having a maleimide group in its molecule and being different from maleimide compound (A) described above. Examples of maleimide compound (D) include maleimide compounds having one or more maleimide groups in their molecule, and modified maleimide compounds. Specific examples of maleimide compound (D) include phenyl maleimide compounds such as 4,4'-diphenylmethanebismaleimide, polyphenylmethanemaleimide, m-phenylenebismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, biphenylaralkyl type polymaleimide compounds, and N-alkylbismaleimide compounds having an aliphatic skeleton. Examples of the modified maleimide compounds include modified maleimide compounds in which a portion of the molecule is modified with an amine compound, and modified maleimide compounds in which a portion of the molecule is modified with a silicone compound.

[0079] Among these, it is preferable to use a maleimide compound (D) that has an aromatic ring and a maleimide equivalent of 150 to 250. This has the advantage of providing heat resistance and a high Tg, and maintaining the elastic modulus over a wide temperature range. Specifically, it is preferable to include, for example, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide.

[0080] As the maleimide compound (D), commercially available products may be used, for example, the solid content in MIR-3000-70MT manufactured by Nippon Kayaku Co., Ltd.; BMI-4000, BMI-5100, BMI-2300, BMI-1000 manufactured by Yamato Kasei Kogyo Co., Ltd.; and BMI-689, BMI-1500, BMI-3000J, etc. manufactured by Designer Molecules Inc.

[0081] The benzoxazine compound (E) is a benzoxazine compound other than the benzoxazine compounds included in the reaction product (B) (i.e., benzoxazine compound (B1) and / or benzoxazine compound (B2)), and is a benzoxazine compound having a benzoxazine group in its molecule, and is not particularly limited as long as it is a benzoxazine compound other than the benzoxazine compound (B1) and benzoxazine compound (B2) described above. Examples of benzoxazine compound (E) include benzoxazine compounds having a phenolphthalein structure in the molecule (phenolphthalein-type benzoxazine compounds), bisphenol F-type benzoxazine compounds, diaminodiphenylmethane (DDM)-type benzoxazine compounds, and benzoxazine compounds having an allyl group in the molecule. More specifically, other benzoxazine compounds include 3,3'-(methylene-1,4-diphenylene)bis(3,4-dihydro-2H-1,3-benzoxazine) (P-d type benzoxazine compound), 2,2-bis(3,4-dihydro-2H-3-phenyl-1,3-benzoxazine)methane (F-a type benzoxazine compound), and oxydianiline (ODA) type benzoxazines.

[0082] The epoxy compound is a compound having an epoxy group in its molecule, and specifically includes bisphenol-type epoxy compounds such as bisphenol A-type epoxy compounds, phenol novolac-type epoxy compounds, cresol novolac-type epoxy compounds, dicyclopentadiene-type epoxy compounds, bisphenol A novolac-type epoxy compounds, biphenyl aralkyl-type epoxy compounds, naphthalene ring-containing epoxy compounds, and polybutadiene compounds having an epoxy group in their molecule. The epoxy compound also includes epoxy resins, which are polymers of each of the epoxy compounds. Among these, it is preferable to include dicyclopentadiene-type epoxy compounds and polybutadiene compounds having an epoxy group in their molecule, as this has the advantage of improving the compatibility between the maleimide compound (A) and the styrene copolymer (C).

[0083] The methacrylate compound is a compound having a methacryloyl group in its molecule, and examples include monofunctional methacrylate compounds having one methacryloyl group in their molecule, and polyfunctional methacrylate compounds having two or more methacryloyl groups in their molecule. Examples of the monofunctional methacrylate compound include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Examples of the polyfunctional methacrylate compound include dimethacrylate compounds such as tricyclodecanedimethanol dimethacrylate (DCP).

[0084] The acrylate compound is a compound having an acryloyl group in its molecule, and examples include monofunctional acrylate compounds having one acryloyl group in their molecule, and polyfunctional acrylate compounds having two or more acryloyl groups in their molecule. Examples of the monofunctional acrylate compound include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. Examples of the polyfunctional acrylate compound include diacrylate compounds such as tricyclodecanedimethanol diacrylate.

[0085] The vinyl compound is a compound having a vinyl group in its molecule, and examples include monofunctional vinyl compounds (monovinyl compounds) having one vinyl group in their molecule, and polyfunctional vinyl compounds having two or more vinyl groups in their molecule. Examples of the polyfunctional vinyl compound include divinylbenzene, curable polybutadiene having a carbon-carbon unsaturated double bond in its molecule, butadiene-styrene copolymers other than styrene polymers (C), polyphenylene ether compounds having vinyl benzyl groups (ethenyl benzyl groups) at their ends, and modified polyphenylene ethers obtained by modifying the terminal hydroxyl groups of polyphenylene ether with methacrylic groups. Examples of butadiene-styrene copolymers other than styrene polymers (C) include curable butadiene-styrene copolymers having a carbon-carbon unsaturated double bond in their molecule that are liquid at 25°C, curable butadiene-styrene random copolymers having a carbon-carbon unsaturated double bond in their molecule, and curable butadiene-styrene random copolymers having a carbon-carbon unsaturated double bond in their molecule that are liquid at 25°C.

[0086] The cyanate ester compound is a compound having a cyanate group in its molecule, and examples include 2,2-bis(4-cyanatephenyl)propane, bis(3,5-dimethyl-4-cyanatephenyl)methane, and 2,2-bis(4-cyanatephenyl)ethane.

[0087] The aforementioned active ester compounds are compounds having highly reactive ester groups in their molecules, and examples include benzenecarboxylic acid active esters, benzenedicarboxylic acid active esters, benzenetricarboxylic acid active esters, benzenetetracarboxylic acid active esters, naphthalenecarboxylic acid active esters, naphthalenedicarboxylic acid active esters, naphthalentricarboxylic acid active esters, naphthalenetetracarboxylic acid active esters, fluorenecarboxylic acid active esters, fluorentricarboxylic acid active esters, and fluorenetetracarboxylic acid active esters.

[0088] The allyl compounds are compounds having an allyl group in their molecule, and examples include triallyl isocyanurate compounds such as triallyl isocyanurate (TAIC), diallyl bisphenol compounds, allyl epoxy compounds, and diallyl phthalate (DAP).

[0089] The aforementioned organic component may be used alone or in combination of two or more types.

[0090] The weight-average molecular weight of the organic component is not particularly limited, but is preferably 100 to 5000, more preferably 100 to 4000, and even more preferably 100 to 3000. If the weight-average molecular weight of the organic component is too low, the organic component may easily volatilize from the resin composition's compounding system. If the weight-average molecular weight of the organic component is too high, the viscosity of the varnish of the resin composition and the melt viscosity during heat molding may become too high, potentially leading to deterioration of appearance and moldability when the resin is in the B stage. Therefore, when the weight-average molecular weight of the organic component is within this range, a resin composition with superior heat resistance and moldability of the cured product can be obtained. This is thought to be because the resin composition can be cured suitably. Here, the weight-average molecular weight can be any value measured by a general molecular weight measurement method, specifically, values ​​measured using gel permeation chromatography (GPC), etc.

[0091] The average number of functional groups per molecule of the organic component that contribute to the reaction during curing of the resin composition (number of functional groups) varies depending on the weight-average molecular weight of the organic component, but is preferably 1 to 20, and more preferably 2 to 18. If the number of functional groups is too small, it tends to be difficult to obtain a cured product with sufficient heat resistance. On the other hand, if the number of functional groups is too large, the reactivity becomes too high, which may cause problems such as a decrease in the shelf life of the resin composition or a decrease in the fluidity of the resin composition.

[0092] If other organic components as described above are included, their content is preferably 10 to 30% by mass relative to the total of the maleimide compound (A), reaction product (B), styrene polymer (C), and other organic components. A more preferred range for the content is 15 to 25% by mass. If the resin composition of this embodiment includes maleimide compound (D), the content of maleimide compound (D) is preferably 10 to 30% by mass, and more preferably 15 to 25% by mass, relative to the total of the maleimide compound (A), reaction product (B), styrene polymer (C), and other organic components (including maleimide compound (D)).

[0093] (Inorganic Filler) The resin composition of this embodiment may contain an inorganic filler as needed, to the extent that it does not impair the effects of the present invention. It is believed that this can further reduce the thermal expansion coefficient of the cured resin composition. The inorganic filler is not particularly limited as long as it is an inorganic filler that can be used as an inorganic filler contained in the resin composition. Examples of materials for the inorganic filler include metal oxides, metal hydroxides, molybdates, nitrides, titanates, magnesium carbonate such as anhydrous magnesium carbonate, calcium carbonate, quartz glass, talc, aluminum borate, and barium sulfate. Examples of metal oxides include silica, alumina, titanium oxide, magnesium oxide, and mica. Examples of silica include crushed silica, spherical silica such as molten spherical silica, and silica particles. Examples of metal hydroxides include magnesium hydroxide and aluminum hydroxide. Examples of molybdates include zinc molybdate, calcium molybdate, and magnesium molybdate. Examples of nitrides include aluminum nitride and boron nitride. Examples of the titanate include barium titanate, strontium titanate, calcium titanate, and aluminum titanate. Among these, a filler made of at least one material selected from silica, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, aluminum oxide, boron nitride, strontium titanate, calcium titanate, and zinc molybdate is preferred, with silica filler being more preferred. The inorganic filler may be used alone or in combination of two or more types. When using two or more of the inorganic fillers in combination, silica filler may be used in combination with one or more inorganic fillers other than silica.

[0094] The inorganic filler may be a surface-treated inorganic filler or an untreated inorganic filler. Examples of surface treatments include treatment with a silane coupling agent.

[0095] The silane coupling agent is not particularly limited, and examples include silane coupling agents having at least one functional group selected from the group consisting of vinyl group, styryl group, methacryloyl group, acryloyl group, phenylamino group, isocyanurate group, ureido group, mercapto group, isocyanate group, epoxy group, and acid anhydride group. That is, this silane coupling agent has at least one of vinyl group, styryl group, methacryloyl group, acryloyl group, phenylamino group, isocyanurate group, ureido group, mercapto group, isocyanate group, epoxy group, and acid anhydride group as a reactive functional group, and further includes compounds having hydrolyzable groups such as methoxy group and ethoxy group.

[0096] Examples of silane coupling agents having a vinyl group include vinyltriethoxysilane and vinyltrimethoxysilane. Examples of silane coupling agents having a styryl group include p-styryltrimethoxysilane and p-styryltriethoxysilane. Examples of silane coupling agents having a methacryloyl group include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropylethyldiethoxysilane. Examples of silane coupling agents having an acryloyl group include 3-acryloxypropyltrimethoxysilane and 3-acryloxypropyltriethoxysilane. Examples of silane coupling agents having a phenylamino group include N-phenyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltriethoxysilane.

[0097] The inorganic filler content is preferably 50 to 250 parts by mass per 100 parts by mass of the total of the maleimide compound (A), reaction product (B), and styrene polymer (C). This is thought to have the advantage of allowing the cured product to have a lower coefficient of thermal expansion. A more preferable range for the content is 100 parts by mass or more and 250 parts by mass or less.

[0098] (Other Components) The resin composition according to this embodiment may contain components other than those described above (other components) as necessary, as long as they do not impair the effects of the present invention. Examples of other components contained in the resin composition according to this embodiment include catalysts such as reaction initiators and reaction accelerators, flame retardants, polymerization inhibitors, polymerization retardants, free radical compounds, flame retardant aids, defoamers, leveling agents, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, additives such as dyes and pigments, dispersants and lubricants.

[0099] As described above, the thermosetting resin composition of this embodiment may contain a reaction initiator. The reaction initiator is not particularly limited as long as it can promote the curing reaction of the thermosetting resin composition, and examples include peroxides and organic azo compounds. Examples of peroxides include α,α'-di(t-butylperoxy)diisopropylbenzene (PBP), 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexine, and benzoyl peroxide. Examples of organic azo compounds include azobisisobutyronitrile. In addition, metal carboxylate salts can be used in combination as needed. By doing so, the curing reaction can be further promoted. The reaction initiator may be used alone or in combination of two or more types.

[0100] As described above, the thermosetting resin composition according to this embodiment may contain a curing accelerator. The curing accelerator is not particularly limited as long as it can accelerate the curing reaction of the thermosetting resin composition. Specifically, examples of the curing accelerator include imidazoles and their derivatives, organophosphorus compounds, amines such as secondary and tertiary amines, quaternary ammonium salts, organoboron compounds, and metal soaps. Examples of the imidazoles include 2-ethyl-4-methylimidazole (2E4MZ), 2-methylimidazole, 2-phenyl-4-methylimidazole, 2-phenylimidazole, and 1-benzyl-2-methylimidazole. Examples of the organophosphorus compounds include triphenylphosphine, diphenylphosphine, phenylphosphine, tributylphosphine, and trimethylphosphine. Examples of the amines include dimethylbenzylamine, triethylenediamine, triethanolamine, and 1,8-diazabicyclo(5,4,0)undecene-7 (DBU). Examples of the quaternary ammonium salt include tetrabutylammonium bromide. Examples of the organoboron compounds include tetraphenylboron salts such as 2-ethyl-4-methylimidazole tetraphenylborate, and tetrasubstituted phosphonium tetrasubstituted borates such as tetraphenylphosphonium ethyltriphenylborate. The metal soap refers to a fatty acid metal salt, which may be a linear fatty acid metal salt or a cyclic fatty acid metal salt. Specifically, examples of the metal soap include linear aliphatic metal salts and cyclic aliphatic metal salts having 6 to 10 carbon atoms. More specifically, examples include aliphatic metal salts consisting of linear fatty acids such as stearic acid, lauric acid, ricinoleic acid, and octic acid, or cyclic fatty acids such as naphthenic acid, and metals such as lithium, magnesium, calcium, barium, copper, and zinc. For example, zinc octoate is one example. The curing accelerator may be used alone or in combination of two or more types.

[0101] (Applications) The resin composition of this embodiment is mainly used in the manufacture of prepregs, as will be described later. In addition to prepregs, the resin composition of this embodiment is used in the formation of resin layers in resin-coated metal foils and resin-coated films, and insulating layers in metal-clad laminates and wiring boards.

[0102] The resin composition according to this embodiment is a resin composition that has a low coefficient of thermal expansion, a high Tg, and heat resistance in the cured product, and can maintain its elastic modulus over a wide temperature range. Therefore, a wiring board equipped with an insulating layer formed using the resin composition according to this embodiment has the advantages of excellent heat resistance, high reliability, and less warping.

[0103] (Manufacturing Method) The method for manufacturing the resin composition of this embodiment is not particularly limited, and examples include mixing a maleimide compound (A), a reaction product (B), and a styrene polymer (C) with other organic components and / or additives as needed, and then adding an inorganic filler or the like. Specifically, when obtaining a varnish-like composition containing an organic solvent, the method described in the prepreg description below can be used.

[0104] By using the resin composition according to this embodiment, prepregs, metal-clad laminates, wiring boards, resin-coated metal foils, and resin-coated films can be obtained as follows.

[0105] (Prepreg, resin-coated film, metal-clad laminate, wiring board, and resin-coated metal foil) Next, a prepreg, metal-clad laminate, wiring board, and resin-coated metal foil for wiring boards using the resin composition of this embodiment will be described. In the following description, each reference numeral in the figure indicates: 1 prepreg, 2 resin composition or semi-cured resin composition, 3 fibrous substrate, 11 metal-clad laminate, 12 insulating layer, 13 metal foil, 14 wiring, 21 wiring board, 31 resin-coated metal foil, 32, 42 resin layer, 41 resin-coated film, 43 support film.

[0106] Figure 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention.

[0107] As shown in Figure 1, the prepreg 1 according to this embodiment comprises the resin composition or a semi-cured product 2 of the resin composition and a fibrous base material 3. An example of this prepreg 1 is one in which the fibrous base material 3 is present within the resin composition or its semi-cured product 2. That is, this prepreg 1 comprises the resin composition or its semi-cured product and the fibrous base material 3 present within the resin composition or its semi-cured product 2.

[0108] In this embodiment, "semi-cured product" refers to a resin composition that has been partially cured to the extent that it can be further cured. In other words, a semi-cured product is a resin composition that has been partially cured (stage B). For example, when a resin composition is heated, its viscosity gradually decreases at first, and then curing begins, causing the viscosity to gradually increase. In such a case, a semi-cured state would be the state between the time the viscosity begins to increase and before it is completely cured.

[0109] The prepreg obtained using the resin composition according to this embodiment may include a semi-cured product of the resin composition as described above, or it may include the uncured resin composition itself. That is, it may be a prepreg comprising a semi-cured product of the resin composition (the resin composition in stage B) and a fibrous substrate, or it may be a prepreg comprising the uncured resin composition (the resin composition in stage A) and a fibrous substrate. Specifically, for example, a prepreg in which a fibrous substrate is present in the resin composition can be mentioned. The resin composition or its semi-cured product may be obtained by heat-drying the resin composition.

[0110] The resin composition according to this embodiment is often prepared in a varnish-like form and used as a resin varnish when manufacturing the prepreg, or resin-coated metal foil or metal-clad laminate described later. Such a resin varnish is prepared, for example, as follows.

[0111] First, each component that can be dissolved in an organic solvent, such as the resin component and reaction initiator, is added to the organic solvent and dissolved. Heating may be performed as needed during this process. Subsequently, an inorganic filler or other component that is not soluble in the organic solvent is added, and the mixture is dispersed using a ball mill, bead mill, planetary mixer, roll mill, etc., until a predetermined dispersion state is reached, thereby preparing a varnish-like resin composition. The organic solvent used here is not particularly limited as long as it dissolves the resin components, such as the maleimide compound (A), the reaction product (B), and the styrene polymer (C), and does not inhibit the curing reaction. Specifically, examples include toluene, methyl ethyl ketone, cyclohexanone, cyclopentanone, methylcyclohexane, dimethylformamide, and propylene glycol monomethyl ether acetate. These may be used individually or in combination of two or more.

[0112] A method for producing the prepreg 1 of this embodiment using the varnish-like resin composition of this embodiment is, for example, to impregnate a fibrous substrate 3 with the resin varnish-like resin composition 2 and then dry it.

[0113] Specific examples of fibrous base materials used in the manufacture of prepregs include glass cloth, aramid cloth, polyester cloth, LCP (liquid crystal polymer) nonwoven fabric, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. When glass cloth is used, a laminate with excellent mechanical strength can be obtained, and flattened glass cloth is particularly preferred. The glass cloth used in this embodiment is not particularly limited, but examples include low dielectric constant glass cloths such as E glass, S glass, T glass, NE glass, Q glass, L glass, L2 glass, and NER glass. Specifically, the flattening process can be carried out by continuously pressing the glass cloth with a press roll at an appropriate pressure to flatten the yarn. The thickness of the fibrous base material can generally be 0.01 to 0.3 mm.

[0114] The resin varnish (resin composition 2) is impregnated into the fibrous substrate 3 by dipping, coating, etc. This impregnation can be repeated multiple times as needed. Furthermore, it is possible to repeat the impregnation using multiple resin varnishes with different compositions and concentrations to finally adjust to the desired composition (content ratio) and resin amount.

[0115] A fibrous substrate 3 impregnated with resin varnish (resin composition 2) is heated under desired heating conditions, for example, at 80°C or higher and 180°C or lower for 1 minute or more and 10 minutes or less. Heating causes the solvent to volatilize from the varnish, reducing or removing the solvent to obtain a prepreg 1 in a pre-cured state (Stage A) or a semi-cured state (Stage B).

[0116] Furthermore, as shown in Figure 4, the resin-coated metal foil 31 of this embodiment has a structure in which a resin layer 32 containing the above-mentioned resin composition or a semi-cured product of the resin composition and a metal foil 13 are laminated together. That is, the resin-coated metal foil of this embodiment may be a resin-coated metal foil comprising a resin layer containing the resin composition before curing (the resin composition in stage A) and a metal foil, or it may be a resin-coated metal foil comprising a resin layer containing a semi-cured product of the resin composition (the resin composition in stage B) and a metal foil.

[0117] One method for producing such resin-coated metal foil 31 is to apply a resin varnish-like resin composition, as described above, to the surface of a metal foil 13 such as copper foil, and then dry it. Examples of such application methods include bar coaters, comma coaters, die coaters, roll coaters, gravure coaters, and the like.

[0118] The metal foil 13 can be any metal foil used in metal-clad laminates, wiring boards, etc., for example, copper foil and aluminum foil.

[0119] Furthermore, as shown in Figure 5, the resin-coated film 41 of this embodiment has a structure in which a resin layer 42 containing the above-mentioned resin composition or a semi-cured product of the resin composition and a film support substrate 43 are laminated together. That is, the resin-coated film of this embodiment may be a resin-coated film comprising the resin composition before curing (the resin composition in stage A) and a film support substrate, or it may be a resin-coated film comprising a semi-cured product of the resin composition (the resin composition in stage B) and a film support substrate.

[0120] As a method for producing such a resin-coated film 41, for example, a resin varnish-like resin composition as described above can be applied to the surface of a film support substrate 43, and then the solvent can be evaporated from the varnish to reduce the amount of solvent, or the solvent can be removed, thereby obtaining a resin-coated film in a pre-cured state (Stage A) or a semi-cured state (Stage B).

[0121] Examples of the film support substrate include electrically insulating films such as polyimide film, PET (polyethylene terephthalate) film, polyethylene naphthalate film, polyester film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, aramid film, polycarbonate film, and polyarylate film.

[0122] In addition, in the resin-coated film and resin-coated metal foil of this embodiment, similar to the prepreg described above, the resin composition or its semi-cured product may be obtained by drying or heat-drying the resin composition.

[0123] The thickness of the metal foil 13 and the film support substrate 43 can be set appropriately according to the desired purpose. For example, the metal foil 13 can be approximately 0.2 to 70 μm thick. If the thickness of the metal foil is, for example, 10 μm or less, a carrier-equipped copper foil with a release layer and carrier may be used to improve handling. The resin varnish is applied to the metal foil 13 and the film support substrate 43 by coating, and this can be repeated multiple times as needed. In this case, it is also possible to repeatedly coat using multiple resin varnishes with different compositions and concentrations to finally adjust to the desired composition (content ratio) and amount of resin.

[0124] The drying or heat drying conditions in the manufacturing method of the resin-coated metal foil 31 and resin-coated film 41 are not particularly limited, but after applying a resin varnish-like resin composition to the metal foil 13 or film support substrate 43, the resin is heated under desired heating conditions, for example, at 50 to 180°C for about 0.1 to 10 minutes, to evaporate the solvent from the varnish and reduce or remove the solvent, thereby obtaining the resin-coated metal foil 31 or resin-coated film 41 in a pre-cured state (A stage) or a semi-cured state (B stage).

[0125] The resin-coated metal foil 31 and the resin-coated film 41 may be provided with a cover film or the like, if necessary. Providing a cover film can prevent the incorporation of foreign matter. The cover film is not particularly limited as long as it can be peeled off without damaging the form of the resin composition, but for example, polyolefin film, polyester film, TPX film, films formed by providing a release agent layer on these films, and paper obtained by laminating these films onto a paper substrate can be used.

[0126] As shown in Figure 2, the metal-clad laminate 11 of this embodiment is characterized by having an insulating layer 12 containing a cured product of the resin composition or a cured product of the prepreg described above, and a metal foil 13. The metal foil 13 used in the metal-clad laminate 11 can be the same as the metal foil 13 described above.

[0127] Furthermore, the metal-clad laminate 11 of this embodiment can also be made using the resin-coated metal foil 31 or resin-coated film 41 described above.

[0128] As a method for producing a metal-clad laminate using the prepreg 1, resin-coated metal foil 31, or resin-coated film 41 obtained as described above, one or more sheets of the prepreg 1, resin-coated metal foil 31, or resin-coated film 41 are stacked, and then metal foil 13 such as copper foil is stacked on both the top and bottom surfaces or on one or both surfaces. This is then heated and pressurized to laminate and integrate the materials, thereby producing a laminate with metal foil cladding on both sides or on one side. The heating and pressing conditions can be appropriately set depending on the thickness of the laminate to be manufactured, the type of resin composition, etc., but for example, the temperature can be set to 170 to 230°C, the pressure to 1.5 to 5.0 MPa, and the time to 60 to 150 minutes.

[0129] Alternatively, the metal-clad laminate 11 may be manufactured by forming a film-like resin composition on a metal foil 13 and then heating and pressurizing it, without using a prepreg 1 or the like.

[0130] As shown in Figure 3, the wiring board 21 of this embodiment has an insulating layer 12 containing a cured product of the resin composition or a cured product of the prepreg described above, and wiring 14.

[0131] The resin composition of this embodiment is suitably used as a material for the insulating layer of a wiring board. As a method for manufacturing the wiring board 21, for example, a wiring board 21 can be obtained by etching the metal foil 13 on the surface of the metal-clad laminate 11 obtained above to form circuits (wirings), thereby providing a conductor pattern (wirings 14) as a circuit on the surface of the laminate. As a method for forming circuits, in addition to the method described above, examples of circuit formation methods include the semi-additive process (SAP) and the modified semi-additive process (MSAP).

[0132] The prepregs, resin-coated films, and resin-coated metal foils obtained using the resin composition of this embodiment are extremely useful for industrial applications because, in their cured form, they possess a low coefficient of thermal expansion, a high Tg, and heat resistance, and can maintain their elastic modulus over a wide temperature range. Furthermore, the metal-clad laminates and wiring boards obtained by curing them also possess the same excellent properties.

[0133] This specification discloses various aspects of technology as described above, but the main technologies are summarized below.

[0134] A resin composition according to a first aspect of the present invention is a resin composition comprising: a maleimide compound (A) having an indan structure represented by formula (1) in its molecule (A1), a maleimide compound (A2) having an arylene structure bonded in the molecule oriented at the meta position, and a maleimide compound (A3) having the indan structure and an arylene structure bonded in the molecule oriented at the meta position; a reaction product (B) obtained by condensing phenols, diamines, and formaldehyde, and containing a benzoxazine compound (B1) having a structure represented by formula (2); and a styrene polymer (C) that is solid at 25°C.

[0135] A resin composition according to a second aspect of the present invention is a resin composition according to the first aspect, wherein the maleimide compound (A1) is a maleimide compound (A1-a) represented by the above formula (3).

[0136] A third aspect of the present invention is a resin composition in which, in the resin composition of the first aspect, the maleimide compound (A2) is a maleimide compound (A2-a) represented by the above formula (4).

[0137] A fourth aspect of the present invention is a resin composition in which, in the third aspect of the present invention, the maleimide compound (A2-a) is a maleimide compound (A2-a-1) represented by the above formula (5).

[0138] A fifth aspect of the present invention is a resin composition of any of the first to fourth aspects, wherein the styrene polymer (C) comprises at least one selected from the group consisting of methylstyrene (ethylene / butylene) methylstyrene block copolymer, methylstyrene (ethylene-ethylene / propylene) methylstyrene block copolymer, styrene isoprene block copolymer, styrene isoprene styrene block copolymer, styrene (ethylene / butylene) styrene block copolymer, styrene (ethylene-ethylene / propylene) styrene block copolymer, styrene butadiene block copolymer, styrene isobutylene styrene block copolymer, styrene (butadiene / butylene) styrene block copolymer, methylstyrene (styrene / butadiene random copolymer block) methylstyrene copolymer, styrene (styrene / butadiene random copolymer block) styrene copolymer, and hydrogenated products in which at least a portion of these are hydrogenated.

[0139] A resin composition according to the sixth aspect of the present invention is a resin composition according to any of the first to fifth aspects, wherein the reaction product (B) is R in formula (2). ３ and R ４ It contains a benzoxazine compound (B1) in which the allyl group is present.

[0140] A resin composition according to the seventh aspect of the present invention contains a benzoxazine compound (B2) represented by formula (2)' in any of the resin compositions of the first to sixth aspects.

[0141] The eighth aspect of the present invention is a resin composition according to any of the first to seventh aspects of the present invention, further containing an organic component other than the maleimide compound (A), the reaction product (B), and the styrene polymer (C), wherein the organic component includes at least one selected from the group consisting of a maleimide compound (D) different from the maleimide compound (A), a benzoxazine compound (E) different from the benzoxazine compound contained in the reaction product (B), an epoxy compound, a methacrylate compound, an acrylate compound, a vinyl compound, a cyanate ester compound, an active ester compound, and an allyl compound.

[0142] The resin composition according to the ninth aspect of the present invention is the resin composition according to the eighth aspect, wherein the organic component comprises a maleimide compound (D), and the maleimide compound (D) is a maleimide compound having an aromatic ring, and its maleimide equivalent is 150 to 250.

[0143] The resin composition according to the tenth aspect of the present invention is a resin composition according to any of the first to ninth aspects, wherein the content of maleimide compound (A) is 20 to 60% by mass relative to the total of maleimide compound (A), reaction product (B), and styrene polymer (C).

[0144] The resin composition according to the eleventh aspect of the present invention is one in which the content of the reaction product (B) is 10 to 40% by mass relative to the total of the maleimide compound (A), the reaction product (B), and the styrene polymer (C).

[0145] The resin composition according to the twelfth aspect of the present invention is one in which the styrene polymer (C) content is 15 to 50% by mass relative to the total of the maleimide compound (A), the reaction product (B), and the styrene polymer (C) in any of the first to eleventh aspects of the present invention.

[0146] A resin composition according to the thirteenth aspect of the present invention further contains an inorganic filler in the resin composition of any of the first to twelfth aspects.

[0147] The resin composition according to the 14th aspect of the present invention is the resin composition according to the 13th aspect, wherein the content of the inorganic filler is 50 to 250 parts by mass per 100 parts by mass of the total of the maleimide compound (A), reaction product (B), and styrene polymer (C).

[0148] A prepreg according to the fifteenth aspect of the present invention comprises a resin composition according to any of the first to fourteenth aspects or a semi-cured product of the resin composition, and a fibrous substrate.

[0149] A resin-coated film according to the sixteenth aspect of the present invention comprises a resin layer containing a resin composition according to any of the first to fourteenth aspects or a semi-cured product of the resin composition, and a support film.

[0150] A resin-coated metal foil according to the 17th aspect of the present invention comprises a resin layer containing a resin composition according to any of the 1st to 14th aspects or a semi-cured product of the resin composition, and a metal foil.

[0151] A metal-clad laminate according to the eighteenth aspect of the present invention comprises an insulating layer containing a cured product of a resin composition according to any of the first to fourteenth aspects or a cured product of a prepreg according to the fourteenth aspect, and a metal foil.

[0152] A wiring board according to the 19th aspect of the present invention comprises an insulating layer containing a cured product of a resin composition according to any of the 1st to 14th aspects or a cured product of a prepreg according to the 15th aspect, and wiring.

[0153] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited thereto.

[0154] First, the components used in preparing the resin composition in this embodiment will be described.

[0155] <Maleimide Compound (A)> Maleimide compound 1: A maleimide compound (A3) having an indane structure and an arylene structure oriented and bonded at the meta position in its molecule (the maleimide compound represented by formula (7) above, "NE-X-9470S" manufactured by DIC Corporation)

[0156] - Maleimide compound 2: A maleimide compound (A2) having an arylene structure in the molecule that is oriented and bonded at the meta position (maleimide compound (A2-a-1) represented by the above formula (5), solid content in MIR-5000-60T manufactured by Nippon Kayaku Co., Ltd.)

[0157] <Reaction Product (B)> In a 1 L reactor equipped with a condenser, a Dean-Stark apparatus, and a stirrer, 131.1 g of 4,4'-diamino-2,2'-dimethylbiphenyl, 165.7 g of 2-allylphenol, and 377.4 g of toluene were added and dissolved at 75°C. Next, 80.6 g of 92% by mass paraformaldehyde was added in five portions, and the reaction solution was heated to remove the water produced by the dehydration condensation reaction. Furthermore, the reaction solution was heated to 105-110°C and the reaction was continued for 6 hours. After the reaction solution was cooled to room temperature, 102.0 g of toluene was added to dilute it. 151.0 g of 10% by mass aqueous sodium hydroxide solution and 37.7 g of isopropyl alcohol (IPA) were added, and the mixture was stirred for 15 minutes. After standing, the aqueous layer was separated and removed twice, and then 70.0 g of toluene was added to the resulting organic layer to dilute it. 151.0 g of water and 37.7 g of IPA were added to the mixture, stirred for 15 minutes, and allowed to stand. This process of separating and removing the aqueous layer was repeated five times. The resulting organic layer, water, and IPA were removed by vacuum distillation using a rotary evaporator to obtain the reaction product as a toluene solution with a concentration of 51.3% by mass. HPLC analysis of the obtained reaction product revealed that the peak area of ​​the benzoxazine compound (B1) represented by formula (10) below was 56.9%, and the peak area of ​​the benzoxazine compound (B2) represented by formula (11) below was 13.1%.

[0158] <Other Benzoxazine Compounds (E)> • Benzoxazine compound 1: A benzoxazine compound different from benzoxazine compounds (B1) and (B2) (ALPd manufactured by Shikoku Chemicals, Inc.)

[0159] <Styrene-based polymers (C)> ・Styrene-based polymer 1: Hydrogenated styrene (ethylenebutylene) styrene block copolymer ("ToughTec® H1041" manufactured by Asahi Kasei Corporation, weight-average molecular weight Mw 80,000, solid at 25°C) ・Styrene-based polymer 2: Styrene-based polymer acid-modified with maleic anhydride ("C5025" manufactured by Asahi Kasei Corporation, 12% by mass of structural units derived from monomers containing styrene, weight-average molecular weight Mw 160,000, acid value 4 mgCH ３ (ONa / g, solid at 25°C)

[0160] <Other Organic Components> - Maleimide compound 3: Maleimide compound (D), 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide ("BMI-5100" manufactured by Yamato Chemical Industries, Ltd.) - Epoxy compound: Polybutadiene with epoxy groups in the molecule ("JP-100" manufactured by Nippon Soda Co., Ltd.)

[0161] <Reaction Initiator> Peroxide: α,α'-di(t-butylperoxy)diisopropylbenzene ("Perbutyl P (PBP)" manufactured by NOF Corporation)

[0162] <Curing accelerator> ・Imidazole-based curing accelerator: 2-ethyl-4-methylimidazole ("2E4MZ" manufactured by Shikoku Chemicals Co., Ltd.)

[0163] <Inorganic Fillers> • Silica Filler (Spherical silica surface-treated with a silane coupling agent containing a phenylamino group in its molecule; silica particles "SC2500-SXJ" manufactured by Admatex Co., Ltd.) • Zinc Molybdate Filler (Spherical zinc molybdate filler, "Z4SX-A1" manufactured by Admatex Co., Ltd.)

[0164] <Examples 1-5 and Comparative Examples 1-4> [Preparation Method] (Resin Varnish) First, each component was added to toluene in the mixing ratio (parts by mass) shown in Table 1 below, so that the solid content concentration was 35% by mass, and the mixture was stirred. The mixture was stirred for 60 minutes. Then, an inorganic filler was added to the resulting liquid, and the inorganic filler was dispersed using a bead mill. In this way, a varnish-like resin composition (varnish) was obtained.

[0165] Next, the obtained varnish was impregnated into glass cloth (Type #2118, T-glass, manufactured by Nitto Boseki Co., Ltd.), and then heated and dried at 130°C for approximately 3 minutes to obtain a prepreg. At that time, the thickness of the prepreg after curing was adjusted to approximately 104 μm (the organic component content in the resin composition was approximately 44% by mass).

[0166] (Preparation of evaluation substrate) Next, an evaluation substrate (metal-clad laminate) was obtained as follows.

[0167] Twelve of the obtained prepregs were stacked together, and copper foil (Mitsui Mining & Smelting Co., Ltd.'s "3EC-VLP" copper foil, thickness: 12 μm) was placed on both sides. This was used as a pressure-bearing body and heated under vacuum at a heating rate of 3°C / min to a temperature of 220°C. By heating and pressurizing at 220°C for 120 minutes under a pressure of 4 MPa, an evaluation substrate (metal-clad laminate) with a resin layer thickness of approximately 1040 μm was obtained, with copper foil bonded to both sides.

[0168] Evaluation tests were performed using the evaluation substrates (metal-clad laminates) obtained from each of the above examples and comparative examples, according to the method described below.

[0169] <Evaluation Test> (Thermal Expansion Coefficient) An unclad plate, obtained by etching off the copper foil from the evaluation substrate (metal-clad laminate), was used as a test specimen. The thermal expansion coefficient in the planar direction (compression direction, Y direction) of the evaluation substrate at a temperature below the glass transition temperature of the cured resin composition was measured by the TMA method (Thermo-mechanical analysis). Specifically, a TMA device (TMA6000 manufactured by SII Nanotechnology Co., Ltd.) was used for the measurement in compression mode. To eliminate the effect of thermal strain on the test specimen, the test specimen was pulled with a load of 10 g in the Y direction and heated from 30°C to 320°C at a heating rate of 10°C / min, and then cooled to room temperature. After that, the test specimen was compressed with a load of 10 g in the Y direction and heated from 30°C to 320°C at a heating rate of 10°C / min. A temperature displacement chart was obtained during this heating process. Then, the average thermal expansion coefficient between 50 and 100°C was calculated from the temperature displacement chart obtained at this time. A smaller average thermal expansion coefficient (Y-CTE 50-100°C) indicates a more favorable result, and in this test, a value of 5.2 ppm / °C or less was considered a "pass."

[0170] (Oven Heat Resistance) Heat resistance was evaluated in accordance with the JIS C 6481 (1996) standard. The copper-clad laminate, cut to the specified size (50 mm x 50 mm), was placed in a constant temperature bath set to 290°C for one hour and then removed. After that, the heat-treated test pieces were visually inspected and evaluated as pass if no blistering occurred, and fail if blistering occurred.

[0171] (Glass Transition Temperature (Tg)) An unclad plate, obtained by etching off the copper foil from the evaluation substrate (metal-clad laminate), was used as a test specimen, and the Tg of the cured resin composition was measured using a viscoelastic spectrometer "DMS6100" manufactured by Seiko Instruments Inc. At this time, dynamic viscoelasticity measurement (DMA) was performed with a double-arm bending module at a frequency of 10 Hz, and the temperature at which tanδ showed a maximum when the temperature was raised from room temperature to 310°C under the condition of a heating rate of 5°C / min was defined as Tg (°C). In this test, a Tg of 280°C or higher was evaluated as a pass.

[0172] (Retention Rate of Elastic Modulus) In the dynamic viscoelasticity measurement performed to determine the glass transition temperature, the ratio of the storage modulus at 260°C to the storage modulus at 30°C was calculated. In this test, a retention rate of 50% (0.5) or higher was considered acceptable.

[0173] The results are shown in Table 1.

[0174]

[0175] (Discussion) As is clear from the results shown in Table 1, it was confirmed that the resin composition of the present invention yields a cured product with a low coefficient of thermal expansion, high Tg and heat resistance, and the ability to maintain its elastic modulus over a wide temperature range. In contrast, Comparative Example 1, which used a resin composition without the styrene polymer (C) of the present invention, failed to sufficiently suppress the coefficient of thermal expansion and also had poor retention of its elastic modulus. Furthermore, Comparative Examples 2 to 4, which used resin compositions without the reaction product (B) of the present invention, failed to obtain sufficient heat resistance.

[0176] This application is based on Japanese Patent Application No. 2024-168139, filed on 27 September 2024, the contents of which are included in this application.

[0177] In order to express the present invention, the invention has been adequately and sufficiently described above through embodiments with reference to specific examples and drawings, etc. However, those skilled in the art should recognize that it is easy to modify and / or improve the embodiments described above. Therefore, unless the modifications or improvements implemented by those skilled in the art fall outside the scope of the claims described in the claims, such modifications or improvements shall be interpreted as being included within the scope of the claims.

[0178] The present invention has broad industrial applicability in the technical fields related to electronic materials, electronic devices, optical devices, and the like.

Claims

1. A resin composition comprising: a maleimide compound (A) having an indane structure represented by the following formula (1) in its molecule (A1), a maleimide compound (A2) having an arylene structure bonded in the molecule oriented at the meta position, and a maleimide compound (A3) having the indane structure and an arylene structure bonded in the molecule oriented at the meta position; a reaction product (B) obtained by condensing phenols, diamines, and formaldehyde, comprising a benzoxazine compound (B1) having a structure represented by the following formula (2); and a styrene polymer (C) that is solid at 25°C. [In formula (1), Rb independently represents a C1-C10 alkyl group, a C1-C10 alkyloxy group, a C1-C10 alkylthio group, a C6-C10 aryl group, a C6-C10 aryloxy group, a C6-C10 arylthio group, a C3-C10 cycloalkyl group, a halogen atom, a hydroxyl group, or a mercapto group; r is 0-3.] [In formula (2), R １ and R ２ Each independently represents either a methyl group or an ethyl group, R ３ and R ４ Each of these independently represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, v and w are each independently 0 to 4, and the bond position of the benzoxazine ring or NH to the biphenyl group is at the 4,4' position or the 3,4' position.

2. The resin composition according to claim 1, wherein the maleimide compound (A1) comprises a maleimide compound (A1-a) represented by the following formula (3). [In formula (3), Ra independently represents a C1-C10 alkyl group, a C1-C10 alkyloxy group, a C1-C10 alkylthio group, a C6-C10 aryl group, a C6-C10 aryloxy group, a C6-C10 arylthio group, a C3-C10 cycloalkyl group, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group; Rb independently represents a C1-C10 alkyl group, a C1-C10 alkyloxy group, a C1-C10 alkylthio group, a C6-C10 aryl group, a C6-C10 aryloxy group, a C6-C10 arylthio group, a C3-C10 cycloalkyl group, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group; q is 0-4; r is 0-3; and n is 0.95-10.] 3. The resin composition according to claim 1, wherein the maleimide compound (A2) contains a maleimide compound (A2-a) represented by the following formula (4). [In formula (4), Ar represents an arylene group bonded in the meta orientation; R Ａ , R Ｂ , R Ｃ , and R Ｄ each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group; R Ｅ and R Ｆ each independently represents an aliphatic hydrocarbon group; s is 1 to ⑤. ] 4. The resin composition according to claim 3, wherein the maleimide compound (A2-a) comprises a maleimide compound (A2-a-1) represented by the following formula (5). [In equation (5), s is between 1 and 5.] 5. The resin composition according to claim 1, wherein the styrene polymer (C) comprises at least one selected from the group consisting of methylstyrene (ethylene / butylene) methylstyrene block copolymer, methylstyrene (ethylene-ethylene / propylene) methylstyrene block copolymer, styrene isoprene block copolymer, styrene isoprene styrene block copolymer, styrene (ethylene / butylene) styrene block copolymer, styrene (ethylene-ethylene / propylene) styrene block copolymer, styrene butadiene block copolymer, styrene isobutylene styrene block copolymer, styrene (butadiene / butylene) styrene block copolymer, methylstyrene (styrene / butadiene random copolymer block) methylstyrene copolymer, styrene (styrene / butadiene random copolymer block) styrene copolymer, and hydrogenated products in which at least a portion of these are hydrogenated.

6. The reaction product (B) is R in formula (2). ３ and R ４ The resin composition according to claim 1, comprising a benzoxazine compound (B1) in which the group is an allyl group.

7. The resin composition according to claim 1, wherein the reaction product (B) comprises a benzoxazine compound (B2) represented by the following formula (2)'. [In formula (2)', R １ and R ２ Each independently represents either a methyl group or an ethyl group, R ３ and R ４ Each of these independently represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, v and w are each independently 0 to 4, and the bond position of the benzoxazine ring or NH to the biphenyl group is at the 4,4' position or the 3,4' position.

8. The resin composition according to claim 1, further comprising an organic component other than the maleimide compound (A), the reaction product (B), and the styrene polymer (C), wherein the organic component comprises at least one selected from the group consisting of a maleimide compound (D) different from the maleimide compound (A), a benzoxazine compound (E) different from the benzoxazine compound contained in the reaction product (B), an epoxy compound, a methacrylate compound, an acrylate compound, a vinyl compound, a cyanate ester compound, an active ester compound, and an allyl compound.

9. The resin composition according to claim 8, wherein the organic component comprises a maleimide compound (D), and the maleimide compound (D) is a maleimide compound having an aromatic ring, and its maleimide equivalent is 150 to 250.

10. The resin composition according to claim 1, wherein the content of maleimide compound (A) is 20 to 60% by mass relative to the total of maleimide compound (A), reaction product (B), and styrene polymer (C).

11. The resin composition according to claim 1, wherein the content of reaction product (B) is 10 to 40% by mass relative to the total of the maleimide compound (A), reaction product (B), and styrene polymer (C).

12. The resin composition according to claim 1, wherein the content of the styrene polymer (C) is 15 to 50% by mass relative to the total of the maleimide compound (A), the reaction product (B), and the styrene polymer (C).

13. The resin composition according to claim 1, further comprising an inorganic filler.

14. The resin composition according to claim 13, wherein the content of the inorganic filler is 50 to 250 parts by mass per 100 parts by mass of the total of the maleimide compound (A), the reaction product (B), and the styrene polymer (C).

15. A prepreg having a resin composition according to any one of claims 1 to 14 or a semi-cured product of the resin composition and a fibrous substrate.

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

17. A resin-coated metal foil comprising a resin layer containing the resin composition described in any one of claims 1 to 14 or a semi-cured product of the resin composition, and a metal foil.

18. A metal-clad laminate having an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 14, and a metal foil.

19. A wiring substrate having an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 14, and wiring.

20. A metal-clad laminate having an insulating layer containing a cured prepreg according to claim 15 and a metal foil.

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

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