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

Abstract

One aspect of the present invention is a resin composition comprising a maleimide compound (A) having in the molecule an indane structure and / or an arylene structure that is oriented and bonded to a meta position, a radical-polymerizable compound (B), and an acrylic block copolymer (C) containing structural units (c1) represented by formula (1) and structural units (c2) represented by formula (2). The acrylic block copolymer (C) has a number-average molecular weight of at least 10,000, and the structural unit (c1) content is 20 mass% or less with respect to the acrylic block copolymer (C).　In formula (2), Y represents a hydrocarbon group having 4 or more carbon atoms.

Description

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

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

[0002] As the amount of information processed increases in various electronic devices, advances in packaging technology, such as higher integration of semiconductor devices, higher density wiring, and multi-layering, are being made. Furthermore, wiring boards used in various electronic devices are required to be high-frequency compatible, such as millimeter-wave radar substrates for automotive applications. Substrate materials for constituting insulating layers of wiring boards used in various electronic devices are required to have low relative dielectric constants and dielectric loss tangents in order to increase signal transmission speeds and reduce signal transmission losses. Examples of substrate materials with low relative dielectric constants and dielectric loss tangents include the resin compositions described in Patent Document 1.

[0003] Patent Document 1 describes a resin composition containing a maleimide compound, an allyl group-containing benzoxazine compound, and a high-molecular-weight component. Patent Document 1 discloses that it is possible to provide a resin composition that has a small dielectric loss tangent value, excellent adhesion to conductive materials after environmental resistance testing, and is capable of producing a cured product with improved brittleness.

[0004] Substrate materials for forming insulating layers of wiring boards are also required to have a high glass transition temperature and to produce cured products with a low coefficient of thermal expansion.

[0005] Japanese Patent Application Laid-Open No. 2020-158705

[0006] The present invention has been made in view of the above circumstances, and aims to provide a resin composition that can give a cured product having a high glass transition temperature and a low thermal expansion coefficient. It is also an object of the present invention to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using the resin composition.

[0007] One aspect of the present invention is a resin composition comprising: a maleimide compound (A) having, in the molecule, at least one of an indane structure and an arylene structure bonded to a meta position, a radically polymerizable compound (B), and an acrylic block copolymer (C) including a structural unit (c1) represented by the following formula (1) and a structural unit (c2) represented by the following formula (2), wherein the acrylic block copolymer (C) has a number average molecular weight of 10,000 or more, and the content of the structural unit (c1) is 20 mass% or less relative to the mass of the acrylic block copolymer (C).

[0008]

[0009] In formula (2), Y represents a hydrocarbon group having 4 or more carbon atoms.

[0010] These and other objects, features, and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

[0011] Fig. 1 is a schematic cross-sectional view showing an example of a prepreg according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate according to an embodiment of the present invention. Fig. 3 is a schematic cross-sectional view showing an example of a wiring board according to an embodiment of the present invention. Fig. 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil according to an embodiment of the present invention. Fig. 5 is a schematic cross-sectional view showing an example of a resin-coated film according to an embodiment of the present invention.

[0012] Electronic devices, particularly small portable devices such as mobile communication terminals and notebook PCs, are rapidly becoming more multifunctional, high-performance, thin, and compact. Accordingly, wiring boards used in these products are also required to have finer conductor wiring, more multilayered conductor wiring layers, thinner designs, and improved mechanical properties. In particular, as wiring boards become thinner, warping occurs in semiconductor packages mounting semiconductor chips on the wiring board, which increases the likelihood of mounting defects. To suppress warping in semiconductor packages mounting semiconductor chips on wiring boards, the insulating layer is required to have a low thermal expansion coefficient (thermal expansion rate). Therefore, substrate materials for forming the insulating layer of wiring boards are required to produce cured products with a low thermal expansion coefficient.

[0013] Wiring boards used in various electronic devices are also required to be less susceptible to changes in the external environment, etc. For example, so that wiring boards can be used even in relatively high-temperature environments, substrate materials for constituting the insulating layer of wiring boards are required to produce cured products with excellent heat resistance, such as a high glass transition temperature. It is also required that the insulating layer provided on the wiring board does not deform even in relatively high-temperature environments. A high glass transition temperature of the insulating layer suppresses this deformation, so substrate materials for constituting the insulating layer of wiring boards are required to have a high glass transition temperature.

[0014] As a result of extensive investigations, the present inventors have found that the above-mentioned object of providing a resin composition that gives a cured product having a high glass transition temperature and a low thermal expansion coefficient can be achieved by the present invention described below.

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

[0016] [Resin Composition] A resin composition according to one embodiment of the present invention comprises a maleimide compound (A), a radically polymerizable compound (B), and an acrylic block copolymer (C). The maleimide compound (A) has at least one of an indane structure and an arylene structure bonded to a meta-position in the molecule. The acrylic block copolymer (C) comprises an acrylic block copolymer (C) containing a structural unit (c1) represented by the following formula (1) and a structural unit (c2) represented by the following formula (2), and the content of the structural unit (c1) is 20 mass% or less relative to the acrylic block copolymer (C). The acrylic block copolymer (C) has a number average molecular weight of 10,000 or more. By curing the resin composition, a cured product having a high glass transition temperature and a low thermal expansion coefficient can be obtained.

[0017]

[0018] In formula (2), Y represents a hydrocarbon group having 4 or more carbon atoms.

[0019] (Maleimide Compound (A)) As described above, the maleimide compound (A) has at least one of an indane structure and an arylene structure bonded in a meta-oriented manner in the molecule. Specifically, the maleimide compound (A) includes at least one selected from the group consisting of a maleimide compound (A1) having an arylene structure bonded in a meta-oriented manner in the molecule, a maleimide compound (A2) having an indane structure in the molecule, and a maleimide compound (A3) having an indane structure and an arylene structure bonded in a meta-oriented manner in the molecule. Furthermore, the maleimide compound (A) may include any one of the maleimide compound (A1), the maleimide compound (A2), and the maleimide compound (A3), and may also include a maleimide compound (A4) other than these.

[0020] (Maleimide Compound (A1) Having an Arylene Structure in the Molecule That is Oriented to a Meta Position) The maleimide compound (A1) is not particularly limited as long as it is a maleimide compound that has an arylene structure in the molecule that is oriented to a meta position. The maleimide compound (A1) has not only the arylene structure but also a maleimide group in the molecule. Examples of the arylene structure include an arylene structure in which a structure containing a maleimide group is bonded to the meta position (an arylene structure in which a structure containing a maleimide group is substituted at the meta position). The arylene structure is an arylene group that is oriented to a meta position, such as a group represented by the following formula (5). Examples of the arylene structure include m-arylene groups such as an m-phenylene group and an m-naphthylene group, and more specifically, a group represented by the following formula (5).

[0021]

[0022] Examples of the maleimide compound (A1) include a maleimide compound (A1-1) represented by the following formula (3), and more specifically, a maleimide compound (A1-2) represented by the following formula (6):

[0023]

[0024] In formula (3), Ar represents an arylene group bonded in a meta orientation. Ａ , R Ｂ , R Ｃ , and R Ｄ are independent of each other. That is, R Ａ , R Ｂ , R Ｃ , and R Ｄ may be the same group or different groups. Ａ , R Ｂ , R Ｃ , and R Ｄ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and is preferably a hydrogen atom. Ｅ and R Ｆ are independent of each other. That is, R Ｅ and R Ｆ may be the same group or different groups. Ｅ and R Ｆ represents an aliphatic hydrocarbon group. s represents 1 to 5.

[0025] The arylene group is not particularly limited as long as it is an arylene group oriented and bonded at the meta position, and examples thereof include m-arylene groups such as an m-phenylene group and an m-naphthylene group, and more specific examples thereof include groups represented by the formula (5).

[0026] Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a neopentyl group.

[0027] The aliphatic hydrocarbon group is a divalent group and may be acyclic or cyclic. Examples of the aliphatic hydrocarbon group include alkylene groups, more specifically methylene groups, methylmethylene groups, and dimethylmethylene groups. Among these, the dimethylmethylene group is preferred.

[0028] In the maleimide compound (A1-1) represented by the formula (3), the repeating number s is preferably 1 to 5. This s is the average value of the repeating number (degree of polymerization).

[0029] In formula (6), s represents 1 to 5. This s is the same as s in formula (3) and is the average value of the number of repetitions (degree of polymerization).

[0030] The maleimide compound (A1-1) represented by the formula (3) and the maleimide compound (A1-2) represented by the formula (6) may contain a monofunctional compound where s is 0, or a polyfunctional compound such as a heptafunctional or octafunctional compound where s is 6 or more, as long as s is the average value of the repeating number (degree of polymerization) of 1 to 5.

[0031] As the maleimide compound (A1), a commercially available product may be used, for example, the solid content of MIR-5000-60T manufactured by Nippon Kayaku Co., Ltd.

[0032] As the maleimide compound (A1), the maleimide compounds exemplified above may be used alone or in combination of two or more. For example, as the maleimide compound (A1), the maleimide compound (A1-1) represented by formula (3) may be used alone, or two or more maleimide compounds (A1-1) represented by formula (3) may be used in combination. When two or more maleimide compounds (A1-1) represented by formula (3) are used in combination, for example, a maleimide compound (A1) represented by formula (3) other than the maleimide compound (A1-2) represented by formula (6) may be used in combination with the maleimide compound (A1-2) represented by formula (6).

[0033] (Maleimide Compound (A2) Having an Indane Structure in the Molecule) The maleimide compound (A2) is not particularly limited as long as it is a maleimide compound having an indane structure in the molecule. The maleimide compound (A2) has not only the indane structure but also a maleimide group in the molecule. Examples of the indane structure include an indane structure represented by the following formula (4). Specific examples of the maleimide compound (A2) include a maleimide compound (A2-1) represented by the following formula (7).

[0034]

[0035] In formula (4), each Rb is independent. That is, each Rb may be the same group or different groups. For example, when r is 2 or 3, two or three Rb's 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 nitro group, a hydroxyl group, or a mercapto group (thiol group). r represents an integer of 0 to 3.

[0036]

[0037] In formula (7), each Ra is independent. That is, each Ra may be the same group or different groups. For example, when q is 2 to 4, 2 to 4 Ra bonded to the same benzene ring may be the same group or different groups. Ra represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy 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 nitro group, a hydroxyl group, or a mercapto group. Rb's are the same as Rb's in formula (4), and each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy 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 nitro group, a hydroxyl group, or a mercapto group. q represents 0 to 4. r represents 0 to 3. n represents 0.95 to 10.

[0038] r is the average value of the degree of substitution of Rb, and a smaller value is preferable, specifically 0. That is, in the benzene ring to which Rb can be bonded, a hydrogen atom is preferably bonded at the position to which Rb can be bonded. The maleimide compound (A) having such an r is easy to synthesize. This is thought to be due to reduced steric hindrance and increased electron density in the aromatic ring. Furthermore, when r is 1 to 3, Rb is preferably at least one selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms. Furthermore, Ra is preferably at least one selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms. The alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms improves solubility in solvents and suppresses a decrease in the reactivity of the maleimide group, resulting in a suitable cured product. This is thought to be due to a decrease in planarity in the vicinity of the maleimide group, a decrease in crystallinity, and the like.

[0039] Specific examples of the groups represented by Ra and Rb include the following groups.

[0040] The alkyl group having 1 to 10 carbon atoms is not particularly limited, and examples thereof include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0041] The alkyloxy group having 1 to 10 carbon atoms is not particularly limited, and examples thereof include a methyloxy group, an ethyloxy group, a propyloxy group, a hexyloxy group, and a decyloxy group.

[0042] The alkylthio group having 1 to 10 carbon atoms is not particularly limited, and examples thereof include a methylthio group, an ethylthio group, a propylthio group, a hexylthio group, and a decylthio group.

[0043] The aryl group having 6 to 10 carbon atoms is not particularly limited, and examples thereof include a phenyl group and a naphthyl group.

[0044] The aryloxy group having 6 to 10 carbon atoms is not particularly limited, and examples thereof include a phenyloxy group and a naphthyloxy group.

[0045] The arylthio group having 6 to 10 carbon atoms is not particularly limited, and examples thereof include a phenylthio group and a naphthylthio group.

[0046] 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.

[0047] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0048] q is the average value of the substitution degree of Ra, and is preferably 2 to 3, and more preferably 2. The maleimide compound (A2) having such a q is easy to synthesize. This is thought to be because, particularly when q is 2, steric hindrance is reduced and the electron density of the aromatic ring is increased.

[0049] n is the average number of repeats, and as described above, 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 having an indane structure in the molecule represented by formula (4) and the maleimide compound (A2-1) represented by formula (7), the content of the maleimide compound in which n, the average number of repeats (degree of polymerization), is 0, is preferably 32 mass% or less based on the total amount of the maleimide compound (A2).

[0050] The maleimide compound (A2) preferably has a molecular weight distribution (Mw / Mn) measured by gel permeation chromatography (GPC) 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 measured by gel permeation chromatography (GPC).

[0051] (Maleimide Compound (A3) Having an Indane Structure and an Arylene Structure Bonded at the Meta Position in the Molecule) The maleimide compound (A3) is not particularly limited as long as it is a maleimide compound having an indane structure and an arylene structure bonded at the meta position in the molecule. The maleimide compound (A3) has not only the arylene structure and the indane structure but also a maleimide group in the molecule. The arylene structure is the same as the arylene structure bonded at the meta position in the maleimide compound (A1), and the indane structure is the same as the indane structure in the maleimide compound (A2). Specific examples of the maleimide compound (A3) include maleimide compounds represented by the following formulas (8) to (10).

[0052] In formula (8), n represents 0.95 to 10.

[0053] In formula (9), n represents 0.95 to 10.

[0054] In formula (10), n represents 0.95 to 10.

[0055] (Maleimide Compound (A4)) The maleimide compound (A4) is not particularly limited as long as it is a maleimide compound other than the maleimide compound (A1), the maleimide compound (A2), and the maleimide compound (A3). The maleimide compound (A4) is a maleimide compound that has a maleimide group in the molecule and does not have either the arylene structure bonded to the meta position or the indane structure in the molecule. Examples of the maleimide compound (A4) include maleimide compounds having one or more maleimide groups in the molecule, and modified maleimide compounds. Examples of the maleimide compound (A4) include phenylmaleimide compounds such as 4,4'-diphenylmethane bismaleimide, phenylmethane maleimide, m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, and biphenylaralkyl polymaleimide compounds, as well as N-alkyl bismaleimide compounds having an aliphatic skeleton. Examples of the modified maleimide compound 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. As the maleimide compound (D), commercially available products may be used. For example, the solid content of MIR-3000-70MT manufactured by Nippon Kayaku Co., Ltd., BMI-2300, BMI-4000, and BMI-5100 manufactured by Daiwa Kasei Kogyo Co., Ltd., BMI, BMI-70, and BMI-80 manufactured by K.I. Kasei Co., Ltd., and BMI-689, BMI-1500, BMI-3000J, and BMI-5000 manufactured by Designer Molecules Inc. may be used.

[0056] The content of the maleimide compound (A1) is preferably 40 to 100 parts by mass, and more preferably 50 to 100 parts by mass, per 100 parts by mass of the maleimide compound (A). The content of the maleimide compound (A2) is preferably 40 to 100 parts by mass, and more preferably 50 to 100 parts by mass, per 100 parts by mass of the maleimide compound (A). The content of the maleimide compound (A3) is preferably 40 to 100 parts by mass, and more preferably 50 to 100 parts by mass, per 100 parts by mass of the maleimide compound (A). The total content of the maleimide compound (A1), the maleimide compound (A2), and the maleimide compound (A3) is preferably 40 to 100 parts by mass, and more preferably 50 to 100 parts by mass, per 100 parts by mass of the maleimide compound (A). If the content of any of the maleimide compound (A1), the maleimide compound (A2), and the maleimide compound (A3) is too small, it tends to be difficult to obtain a cured product having a high glass transition temperature and a low thermal expansion coefficient from the resin composition. Therefore, by setting the content of any of the maleimide compound (A1), the maleimide compound (A2), and the maleimide compound (A3) within the above range, it becomes easier to obtain a cured product having a high glass transition temperature and a low thermal expansion coefficient from the resin composition.

[0057] (Radical Polymerizable Compound (B)) The radical polymerizable compound (B) is not particularly limited as long as it is a compound different from the maleimide compound (A) and has radical polymerizability. Examples of the radical polymerizable compound (B) include a benzoxazine compound (B1) having an alkenyl group in the molecule, a hydrocarbon-based compound (B2) having a reactive carbon-carbon unsaturated group in the molecule, and a radical polymerizable compound (B3) other than the benzoxazine compound (B1) and the hydrocarbon-based compound (B2). As the radical polymerizable compound (B), these may be used alone or in combination of two or more.

[0058] (Benzoxazine Compound (B1) Having an Alkenyl Group in the Molecule) The benzoxazine compound (B1) is not particularly limited as long as it is a benzoxazine compound having an alkenyl group in the molecule. The benzoxazine compound (B1) has not only an alkenyl group but also a benzoxazine group in the molecule. The alkenyl group is not particularly limited, and examples thereof include alkenyl groups having 2 to 6 carbon atoms. Specific examples of the alkenyl group include vinyl groups, allyl groups, propenyl groups, and butenyl groups, and among these, allyl groups and propenyl groups are preferred. Examples of the benzoxazine group include benzoxazine groups represented by the following formula (11) and benzoxazine groups represented by the following formula (12). Examples of the benzoxazine compound (B1) include not only a benzoxazine compound (B1-1) having a benzoxazine group represented by the following formula (11) in the molecule, and a benzoxazine compound (B1-2) having a benzoxazine group represented by the following formula (12) in the molecule, but also a benzoxazine compound (B1-3) having a benzoxazine group represented by the following formula (11) and a benzoxazine group represented by the following formula (12) in the molecule.

[0059] In formula (11), R １ represents an allyl group, and a represents 1 to 4. a represents R １ is an average value of the degree of substitution of 1 to 4, and is preferably 1.

[0060] In formula (12), R ２ represents an allyl group.

[0061] Specific examples of the benzoxazine compound (B1) include the benzoxazine compound (B1-1) represented by the following formula (14):

[0062] In formula (14), R ３ and R ４ represents an allyl group; X represents an alkylene group; b and c each independently represent 1 to 4.

[0063] The alkylene group is not particularly limited and examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octane group, an icosane group, and a hexatriacontane group. Among these, a methylene group is preferred.

[0064] b is R ３ is the average value of the degree of substitution of R ４ is an average value of the degree of substitution of 1 to 4, and is preferably 1.

[0065] As the benzoxazine compound (B1), a commercially available product may be used, for example, ALPd manufactured by Shikoku Chemicals Corporation.

[0066] As the benzoxazine compound (B1), the benzoxazine compounds exemplified above may be used alone or in combination of two or more.

[0067] (Hydrocarbon Compound (B2) Having a Reactive Carbon-Carbon Unsaturated Group in the Molecule) The hydrocarbon compound (B2) is not particularly limited as long as it is a hydrocarbon compound having a reactive carbon-carbon unsaturated group in the molecule. The reactive carbon-carbon unsaturated group is not particularly limited, but examples thereof include an alkenyl group. Examples of the alkenyl group include alkenyl groups having 2 to 6 carbon atoms, and specific examples include a vinyl group, an allyl group, a propenyl group, and a butenyl group. Among these, an allyl group and a propenyl group are preferred. Examples of the hydrocarbon compound (B2) include divinylbenzene such as o-divinylbenzene, m-divinylbenzene, and p-divinylbenzene; a hydrocarbon compound (B2-1) represented by the following formula (14); and a hydrocarbon compound (B2-2) represented by the following formula (16).

[0068] In formula (14), Z represents a hydrocarbon group having 6 or more carbon atoms, which contains at least one selected from an aromatic cyclic group and an aliphatic cyclic group.

[0069] The aromatic cyclic group is not particularly limited, but examples thereof include a phenylene group, a xylylene group, a naphthylene group, a tolylene group, and a biphenylene group. The aliphatic cyclic group is not particularly limited, but examples thereof include a group containing an indane structure and a group containing a cycloolefin structure. Among these, Z is preferably the aromatic cyclic group, and more preferably a xylylene group. The number of carbon atoms in the hydrocarbon group is not particularly limited as long as it is 6 or more, but is preferably 6 to 20. More specific examples of the hydrocarbon compound (B2-1) include a hydrocarbon compound (B2-1-1) represented by the following formula (15):

[0070] In formula (15), d represents 1 to 10.

[0071] In formula (16), e represents 1 to 20.

[0072] In the hydrocarbon compound (B2-2), e is preferably 1 to 20, more preferably 1 to 12, and even more preferably 1 to 6. Specific examples of the hydrocarbon compound (B2-2) include a compound represented by the formula (16) in which e is 1 [bis-(4-vinylphenyl)methane (BVPM)], a compound represented by the formula (16) in which e is 2 [1,2-bis(vinylphenyl)ethane (BVPE)], and a compound represented by the formula (16) in which e is 6 [1,6-bis(4-vinylphenyl)hexane (BVPH)].

[0073] (Radical Polymerizable Compound (B3)) The radical polymerizable compound (B3) is not particularly limited as long as it is a radical polymerizable compound other than the benzoxazine compound (B1) and the hydrocarbon compound (B2). Examples of the radical polymerizable compound (B3) include polyphenylene ether compounds, methacrylate compounds, acrylate compounds, vinyl compounds, and allyl compounds, each of which has a carbon-carbon unsaturated double bond in the molecule.

[0074] The polyphenylene ether compound is not particularly limited as long as it is a polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule. Examples of the polyphenylene ether compound include polyphenylene ether compounds having a carbon-carbon unsaturated double bond at a terminal, and more specifically, polyphenylene ether compounds having a substituent having a carbon-carbon unsaturated double bond at a molecular terminal, such as modified polyphenylene ether compounds whose terminals are modified with a substituent having a carbon-carbon unsaturated double bond. Examples of the substituent having a carbon-carbon unsaturated double bond include a vinylbenzyl group (ethenylbenzyl group), an acryloyl group, and a methacryloyl group.

[0075] The methacrylate compound is a compound having a methacryloyl group in the molecule, and examples thereof include monofunctional methacrylate compounds having one methacryloyl group in the molecule and polyfunctional methacrylate compounds having two or more methacryloyl groups in the molecule. Examples of the monofunctional methacrylate compound include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Examples of the polyfunctional methacrylate compound include dimethacrylate compounds such as tricyclodecane dimethanol dimethacrylate (DCP).

[0076] The acrylate compound is a compound having an acryloyl group in the molecule, and examples thereof include monofunctional acrylate compounds having one acryloyl group in the molecule and polyfunctional acrylate compounds having two or more acryloyl groups in the molecule. Examples of the monofunctional acrylate compound include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. Examples of the polyfunctional acrylate compound include diacrylate compounds such as tricyclodecane dimethanol diacrylate.

[0077] The vinyl compound is a compound having a vinyl group in the molecule, and examples thereof include monofunctional vinyl compounds (monovinyl compounds) having one vinyl group in the molecule, and polyfunctional vinyl compounds having two or more vinyl groups in the molecule. Examples of the monofunctional vinyl compound include vinylbenzene compounds having a skeleton containing a phosphorus atom in the molecule, such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO).

[0078] The allyl compound is a compound having an allyl group in the molecule, and examples thereof include triallyl isocyanurate compounds such as triallyl isocyanurate (TAIC), diallyl bisphenol compounds, and diallyl phthalate (DAP).

[0079] As the radical polymerizable compound (B), the radical polymerizable compounds exemplified above may be used alone or in combination of two or more kinds.

[0080] (Acrylic Block Copolymer (C)) The acrylic block copolymer (C) is not particularly limited as long as it contains a structural unit (c1) represented by the formula (1) above and a structural unit (c2) represented by the following formula (2), has a number average molecular weight of 10,000 or more, and contains 20 mass% or less of the structural unit (c1). Since the acrylic block copolymer (C) contains the structural unit (c1), the content of the structural unit (c1) is more than 0 mass%.

[0081] Y in the structural unit (c2) is not particularly limited as long as it is a hydrocarbon group having 4 or more carbon atoms. Examples of the hydrocarbon group include butyl, hexyl, pentyl, heptyl, octyl, nonyl, decyl, dodecyl, lauryl, stearyl, docosyl, isostearyl, 1-methylheptyl, 2-ethylhexyl, phenoxyethyl, 2-hydroxyethyl, 2-hydroxypropyl, 2-hydroxybutyl, 4-hydroxybutyl, 2-carboxyethyl, isobornyl, and isoamyl. Among these, butyl and 2-ethylhexyl are preferred as the hydrocarbon group. The structural unit (c2) may contain these groups alone or in combination as the hydrocarbon group. The structural unit (c2) is preferably a structural unit derived from butyl acrylate or a structural unit derived from 2-ethylhexyl acrylate. The structural unit (c1) is a structural unit derived from methyl methacrylate. Therefore, the acrylic block copolymer (C) is preferably a block copolymer of the structural unit (c1) derived from methyl methacrylate and the structural unit (c2) derived from at least one of a structural unit derived from butyl acrylate and a structural unit derived from 2-ethylhexyl acrylate. Examples of the block copolymer include a diblock copolymer of the structural unit (c1) and the structural unit (c2), and a triblock copolymer of the structural unit (c1), the structural unit (c2), and the structural unit (c1), with the triblock copolymer being preferred. Specifically, the acrylic block copolymer (C) is more preferably a block copolymer of methyl methacrylate and butyl acrylate, and even more preferably a triblock copolymer of methyl methacrylate, butyl acrylate, and methyl methacrylate. Furthermore, the structural unit (c1) serves as a hard segment in the acrylic block copolymer (C), and the glass transition temperature thereof is preferably, for example, 100 to 120°C.Furthermore, the structural unit (c2) is a soft segment in the acrylic block copolymer (C), and its glass transition temperature is preferably -60 to -40°C, more preferably -50 to -40°C.

[0082] The content of the structural unit (c1) is 20% by mass or less relative to the acrylic block copolymer (C). Since the acrylic block copolymer (C) contains the structural unit (c1), the content of the structural unit (c1) is greater than 0% by mass. Therefore, the content of the structural unit (c1) is greater than 0% by mass and less than 20% by mass relative to the acrylic block copolymer (A), preferably 1 to 18% by mass, and more preferably 11 to 18% by mass. If the content of the structural unit (c1) in the acrylic block copolymer (A) is too low, the effect of adding the acrylic block copolymer (C) is less likely to be achieved, and it tends to be difficult to obtain a cured product with a low thermal expansion coefficient from the resin composition. Therefore, if the content of the structural unit (c1) is within the above range, it tends to be easier to obtain a cured product with a low thermal expansion coefficient from the resin composition. Furthermore, since the wiring board is required to have finer wiring that does not peel off from the insulating layer, high adhesion between the wiring and the insulating layer is required. When the content of the structural unit (c1) is within the above range, the adhesion between the wiring and the insulating layer is also improved.

[0083] The acrylic block copolymer (C) may contain the structural unit (c1) and the structural unit (c2), and may also contain a structural unit (c3) other than the structural unit (c1) and the structural unit (c2) (another structural unit). The other structural unit is not particularly limited, and examples thereof include structural units derived from methacrylic acid esters other than those derived from methyl methacrylate, structural units derived from methyl acrylate, structural units derived from ethyl acrylate, structural units derived from butyl acrylate, and structural units derived from styrene. Furthermore, examples of structural units derived from methacrylic acid esters other than those derived from methyl methacrylate include structural units derived from ethyl methacrylate, structural units derived from butyl methacrylate, and structural units derived from propyl methacrylate.

[0084] The number average molecular weight of the acrylic block copolymer (C) is 10,000 or more, preferably 30,000 or more, and more preferably 40,000 or more, and is preferably 300,000 or less, and more preferably 200,000 or less. The acrylic block copolymer (C) may be solid or liquid at 25°C, and is preferably solid at 25°C. The number average molecular weight of the acrylic block copolymer (C) is preferably a number average molecular weight that makes it solid at 25°C. If the number average molecular weight is too low, the effect of adding the acrylic block copolymer (C) is less likely to be achieved, and it tends to be difficult to obtain a cured product having a low thermal expansion coefficient from the resin composition. If the number average molecular weight is too high, the compatibility between the maleimide compound (A) and the acrylic block copolymer (C) and the compatibility between the radical polymerizable compound (B) and the acrylic block copolymer (C) will be too low, making it difficult to obtain a normal cured product, and the viscosity of the resin composition when made into a varnish and during heat molding will tend to be too high. Note that the number average molecular weight may be measured by a general molecular weight measurement method, and specific examples include values ​​measured using gel permeation chromatography (GPC).

[0085] (Styrene-based polymer (D)) The resin composition may further contain a styrene-based polymer (D), and preferably contains the styrene-based polymer (D). Electronic devices, particularly small portable devices such as mobile communication terminals and notebook computers, are rapidly becoming more diverse, higher in performance, thinner, and smaller. Accordingly, the wiring boards used in these products are also required to have finer conductor wiring, more multi-layered conductor wiring layers, thinner wiring, and higher performance in mechanical properties. For this reason, the wiring board is required to have finer wiring, but not peel off from the insulating layer. To meet this requirement, the wiring board is required to have high adhesion between the wiring and the insulating layer. Therefore, metal-clad laminates are required to have high adhesion between the metal foil and the insulating layer, and substrate materials for constituting the insulating layer of the wiring board are required to produce cured products with excellent adhesion to the metal foil. Furthermore, as described above, wiring boards are required to be multilayered, and when the insulating layer is configured in multiple layers, high interlayer adhesion is also required to prevent interlayer peeling between the insulating layers. For this reason, substrate materials for forming the insulating layer of wiring boards are required to provide a cured product with excellent adhesion between adjacent cured products, i.e., excellent interlayer adhesion. By containing the styrene-based polymer (D), a resin composition can be obtained that provides a cured product with excellent adhesion and interlayer adhesion to metal foil, as described above. That is, by containing the styrene-based polymer (D), a resin composition can be obtained that not only has a high glass transition temperature and a low thermal expansion coefficient, but also provides a cured product with excellent adhesion and interlayer adhesion to metal foil. The styrene-based polymer (D) is not particularly limited, but examples thereof include styrene-based polymers that are solid at 25°C. More specifically, examples thereof include styrene-based polymers that are solid at 25°C and can be used as resins contained in resin compositions used to form insulating layers in metal-clad laminates, wiring boards, etc. The resin composition used to form insulating layers in metal-clad laminates, wiring boards, etc. may be a resin composition used to form resin layers in resin-coated films and resin-coated metal foils, or a resin composition contained in a prepreg.

[0086] The styrene-based polymer (D) may be, for example, a polymer obtained by polymerizing a monomer containing a styrene-based monomer, and may be a styrene-based copolymer. Examples of the styrene-based copolymer include copolymers obtained by copolymerizing one or more of the styrene-based monomers with one or more other monomers copolymerizable with the styrene-based monomer. 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. Examples of the block copolymer include a binary copolymer of a structure (repeating unit) derived from the styrene-based monomer and the other copolymerizable monomer (repeating unit), and a terpolymer of a structure (repeating unit) derived from the styrene-based monomer, the other copolymerizable monomer (repeating unit), and a structure (repeating unit) derived from the styrene-based monomer. The styrene-based polymer (D) may be a hydrogenated styrene-based copolymer obtained by hydrogenating the styrene-based copolymer. It is preferable that the styrene-based polymer (D) is at least partially hydrogenated. By containing the at least partially hydrogenated styrene-based polymer, a resin composition can be obtained that forms a cured product having excellent adhesion to a metal foil. The styrene-based polymer (D) may be a resin obtained by modifying a part of the styrene-based copolymer, the at least partially hydrogenated styrene-based polymer, or the hydrogenated styrene-based copolymer with maleic anhydride.

[0087] The styrene-based monomer is not particularly limited, but examples thereof include styrene, styrene derivatives, styrene in which some of the hydrogen atoms on the benzene ring have been substituted with alkyl groups, styrene in which some of the hydrogen atoms on the vinyl group have been substituted with alkyl groups, vinyltoluene, α-methylstyrene, butylstyrene, dimethylstyrene, and isopropenyltoluene. These styrene-based monomers may be used alone or in combination of two or more. Furthermore, the copolymerizable other monomer is not particularly limited, but examples thereof include olefins such as α-pinene, β-pinene, and dipentene, non-conjugated dienes such as 1,4-hexadiene and 3-methyl-1,4-hexadiene, and conjugated dienes such as 1,3-butadiene and 2-methyl-1,3-butadiene (isoprene). These copolymerizable other monomers may be used alone or in combination of two or more.

[0088] As the styrene-based polymer (D), a wide variety of conventionally known polymers can be used, and there is no particular limitation. For example, a polymer having a structural unit represented by the following formula (12) (a structure derived from the styrene-based monomer) in the molecule can be used.

[0089]

[0090] In formula (17), R ５ ~R ７ each independently represents a hydrogen atom or an alkyl group, and R ８ represents any group selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, and an isopropenyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group. The alkenyl group is preferably an alkenyl group having 1 to 10 carbon atoms.

[0091] The styrene-based polymer (D) preferably contains at least one structural unit represented by the formula (17), and may contain two or more different structural units in combination. The styrene-based polymer (D) may also contain a structure in which the structural unit represented by the formula (17) is repeated.

[0092] The styrene-based polymer (D) may have, in addition to the structural unit represented by formula (17), at least one of structural units represented by formula (18), formula (19), and formula (20) below, and structures in which the structural units represented by formula (18), formula (19), and formula (20) below are repeated, as structural units derived from other monomers copolymerizable with the styrene-based monomer:

[0093]

[0094]

[0095]

[0096] In the formula (18), the formula (19) and the formula (20), R ９ ~R ２６ are each independently a group selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, and an isopropenyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, and more preferably, an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group. The alkenyl group is preferably an alkenyl group having 1 to 10 carbon atoms.

[0097] The styrene-based polymer (D) preferably contains at least one structural unit represented by the formula (18), the formula (19), or the formula (20), and may contain two or more different structural units in combination. The styrene-based polymer may also have at least one structure in which the structural units represented by the formula (18), the formula (19), or the formula (20) are repeated.

[0098] More specifically, examples of the structural unit represented by formula (17) include structural units represented by the following formulas (21) to (23). The structural unit represented by formula (17) may also be a structure in which the structural units represented by formulas (21) to (23) below are respectively repeated. The structural unit represented by formula (17) may be one of these alone or a combination of two or more different types.

[0099]

[0100]

[0101]

[0102] More specifically, examples of the structural unit represented by formula (18) include structural units represented by the following formulas (24) to (30). The structural unit represented by formula (18) may also be a structure in which the structural units represented by formulas (24) to (30) below are respectively repeated. The structural unit represented by formula (18) may be one of these alone or a combination of two or more different types.

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110] More specifically, the structural unit represented by the formula (19) includes structural units represented by the following formulas (31) and (32). The structural unit represented by the formula (19) may also be a structure in which structural units represented by the following formulas (33) and (34) are respectively repeated. The structural unit represented by the formula (19) may be one of these alone or a combination of two or more different types.

[0111]

[0112]

[0113] More specifically, the structural unit represented by the formula (20) includes structural units represented by the following formulas (33) and (34). The structural unit represented by the formula (20) may also be a structure in which the structural units represented by the following formulas (33) and (34) are respectively repeated. The structural unit represented by the formula (20) may be one of these alone or a combination of two or more different types.

[0114]

[0115]

[0116] Preferred examples of the styrene copolymer (D) include polymers or copolymers obtained by polymerizing or copolymerizing one or more styrene monomers such as styrene, vinyltoluene, α-methylstyrene, isopropenyltoluene, divinylbenzene, and allylstyrene.

[0117] More specific examples of the styrene polymer (D) include styrene-butadiene block copolymers such as methylstyrene (ethylene / butylene) methylstyrene block copolymer, methylstyrene (ethylene-ethylene / propylene) methylstyrene block copolymer, styrene-isoprene block copolymer, hydrogenated styrene-isoprene styrene block copolymer, styrene (ethylene / butylene) styrene block copolymer, styrene (ethylene-ethylene / propylene) styrene block copolymer, methylstyrene (styrene / butadiene random copolymer block) methylstyrene copolymer, styrene (styrene / butadiene random copolymer block) styrene copolymer, styrene-butadiene styrene block copolymer, styrene-isobutylene styrene block copolymer, styrene (butadiene / butylene) styrene block copolymer, and hydrogenated products obtained by hydrogenating at least a portion of these.

[0118] As the styrene-based polymer (D), commercially available products may be used, such as Tuftec P1500, Tuftec H1221, Tuftec H1041, Tuftec H1517, Tuftec M1913, and SOE1605 manufactured by Asahi Kasei Corporation, and Asaprene T437 manufactured by Asahi Kasei Corporation.

[0119] As the styrene-based polymer (D), the above-exemplified styrene-based polymers may be used alone or in combination of two or more.

[0120] The styrene polymer (D) preferably has a weight-average molecular weight of 1,000 to 300,000, more preferably 10,000 to 200,000. If the molecular weight is too low, the glass transition temperature of the cured product of the resin composition tends to decrease, and the heat resistance tends to decrease. If the molecular weight is too high, the viscosity of the resin composition when made into a varnish or during heat molding tends to become too high. The weight-average molecular weight may be measured by a general molecular weight measurement method, and specific examples include values ​​measured using gel permeation chromatography (GPC).

[0121] (Inorganic filler) The resin composition may contain an inorganic filler as needed, as long as the effects of the present invention are not impaired. In addition, it is preferable to contain the inorganic filler from the viewpoint of improving the heat resistance of the cured product of the resin composition. The inorganic filler is not particularly limited as long as it is an inorganic filler that can be used as the inorganic filler contained in the resin composition. Examples of the inorganic filler include silica filler, alumina filler, titanium oxide filler, magnesium oxide filler and mica filler, metal hydroxide filler such as magnesium hydroxide filler and aluminum hydroxide filler, talc filler, aluminum borate filler, barium sulfate filler, aluminum nitride filler, boron nitride filler, barium titanate filler, strontium titanate filler, calcium titanate filler, aluminum titanate filler, magnesium carbonate filler such as anhydrous magnesium carbonate filler, calcium carbonate filler, molybdic acid compound filler such as zinc molybdate filler and calcium molybdate filler, and talc filler carrying the molybdic acid compound.Among these, silica filler, metal hydroxide filler such as magnesium hydroxide filler and aluminum hydroxide filler, aluminum oxide filler, boron nitride filler, strontium titanate filler, calcium titanate filler and zinc molybdate filler are preferred, and silica filler is more preferred. The silica filler is not particularly limited, and for example, crushed silica, spherical silica, silica particles, etc. can be mentioned, and spherical silica is preferred.As the inorganic filler, each of the exemplified inorganic fillers can be used alone, or two or more can be used in combination.When two or more of the inorganic fillers are used in combination, silica filler can be used in combination with one or more inorganic fillers other than silica filler, and it is preferred to use silica filler in combination with zinc molybdate filler.

[0122] The inorganic filler may be a surface-treated or untreated inorganic filler. Examples of the surface treatment include treatment with a silane coupling agent.

[0123] The silane coupling agent is not particularly limited, and examples thereof 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, the silane coupling agent has at least one reactive functional group selected from vinyl group, styryl group, methacryloyl group, acryloyl group, phenylamino group, isocyanurate group, ureido group, mercapto group, isocyanate group, epoxy group, and acid anhydride group, and further includes compounds having a hydrolyzable group such as a methoxy group or an ethoxy group.

[0124] Examples of the silane coupling agent include those having a vinyl group, such as vinyltriethoxysilane and vinyltrimethoxysilane. Examples of the silane coupling agent include those having a styryl group, such as p-styryltrimethoxysilane and p-styryltriethoxysilane. Examples of the silane coupling agent include those having a methacryloyl group, such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropylethyldiethoxysilane. Examples of the silane coupling agent include those having an acryloyl group, such as 3-acryloxypropyltrimethoxysilane and 3-acryloxypropyltriethoxysilane. Examples of the silane coupling agent include those having a phenylamino group, such as N-phenyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltriethoxysilane.

[0125] The average particle size of the inorganic filler is not particularly limited, and is preferably 0.05 to 10 μm, and more preferably 0.1 to 8 μm. Here, the average particle size refers to the volume average particle size. The volume average particle size can be measured, for example, by a laser diffraction method.

[0126] (Content) The content ratio of the maleimide compound (A) to the radical polymerizable compound (B) is preferably 50:50 to 90:10, more preferably 50:50 to 80:20, in mass ratio.

[0127] The content of the maleimide compound (A) is preferably 20 to 80 parts by mass, and more preferably 30 to 70 parts by mass, relative to 100 parts by mass in total of the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C).

[0128] The content of the radical polymerizable compound (B) is preferably 10 to 50 parts by mass, and more preferably 20 to 40 parts by mass, relative to 100 parts by mass in total of the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C).

[0129] The content of the acrylic block copolymer (C) is preferably 5 to 40 parts by mass, and more preferably 5 to 35 parts by mass, relative to 100 parts by mass in total of the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C).

[0130] By incorporating the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C) so that their contents fall within the above ranges, a resin composition can be obtained that has a higher glass transition temperature and a lower coefficient of thermal expansion as a cured product.

[0131] As described above, the resin composition may contain the styrene-based polymer (D). When the resin composition contains the styrene-based polymer (D), the content of the styrene-based polymer (D) is preferably 5 to 40 parts by mass, and more preferably 10 to 30 parts by mass, per 100 parts by mass of the total of the maleimide compound (A), the radical-polymerizable compound (B), and the acrylic block copolymer (C).

[0132] As described above, the resin composition may contain the inorganic filler. When the resin composition contains the inorganic filler, the content of the inorganic filler is preferably 50 to 300 parts by mass per 100 parts by mass of the total of the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C).

[0133] (Other Components) The resin composition may contain components (other components) other than the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C), as long as the effects of the present invention are not impaired. As described above, the resin composition may contain the styrene-based polymer (D) and the inorganic filler as the other components. In addition to the styrene-based polymer and the inorganic filler, examples of the other components include organic components other than the maleimide compound (A), the radical polymerizable compound (B), the acrylic block copolymer (C), and the styrene-based polymer (D), flame retardants, reaction initiators, curing accelerators, catalysts, polymerization retarders, polymerization inhibitors, dispersants, leveling agents, coupling agents, defoamers, antioxidants, heat stabilizers, antistatic agents, UV absorbers, dyes and pigments, and additives such as lubricants.

[0134] As described above, the resin composition according to this embodiment may contain an organic component other than the maleimide compound (A), the radical polymerizable compound (B), the acrylic block copolymer (C), and the styrene polymer (D). The organic component may be, for example, a compound that reacts with or does not react with at least one of the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C). Specific examples of the organic component include oxazine compounds other than the oxazine compound (B1) (other oxazine compounds), epoxy compounds, cyanate ester compounds, and active ester compounds.

[0135] The other oxazine compound is not particularly limited as long as it has an oxazine group in the molecule and is an oxazine compound other than the oxazine compound (B1). Examples of the other oxazine compound include a benzoxazine compound having a phenolphthalein structure in the molecule (phenolphthalein-type benzoxazine compound), a bisphenol F-type benzoxazine compound, and a diaminodiphenylmethane (DDM)-type benzoxazine compound. More specific examples of the other oxazine compound include 3,3'-(methylene-1,4-diphenylene)bis(3,4-dihydro-2H-1,3-benzoxazine) (P-d-type benzoxazine compound) and 2,2-bis(3,4-dihydro-2H-3-phenyl-1,3-benzoxazine)methane (F-a-type benzoxazine compound).

[0136] The epoxy compound is a compound having an epoxy group in the molecule, and specific examples thereof include 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, polybutadiene compounds having an epoxy group in the molecule, and naphthalene ring-containing epoxy compounds. The epoxy compound also includes epoxy resins, which are polymers of the above-mentioned epoxy compounds.

[0137] The cyanate ester compound is a compound having a cyanate group in the molecule, and examples thereof include 2,2-bis(4-cyanatephenyl)propane, bis(3,5-dimethyl-4-cyanatephenyl)methane, and 2,2-bis(4-cyanatephenyl)ethane.

[0138] The active ester compound is a compound having an ester group with high reactivity in the molecule, and examples thereof include benzenecarboxylic acid active ester, benzenedicarboxylic acid active ester, benzenetricarboxylic acid active ester, benzenetetracarboxylic acid active ester, naphthalenecarboxylic acid active ester, naphthalenedicarboxylic acid active ester, naphthalenetricarboxylic acid active ester, naphthalenetetracarboxylic acid active ester, fluorenecarboxylic acid active ester, fluorenedicarboxylic acid active ester, fluorenetricarboxylic acid active ester, and fluorenetetracarboxylic acid active ester.

[0139] As described above, the resin composition according to this embodiment may contain a flame retardant. By including a flame retardant, the flame retardancy of the cured resin composition can be improved. The flame retardant is not particularly limited. Specifically, in fields where halogen-based flame retardants such as bromine-based flame retardants are used, for example, ethylene dipentabromobenzene, ethylene bistetrabromoimide, decabromodiphenyl oxide, tetradecabromodiphenoxybenzene, and bromostyrene-based compounds that react with the polymerizable compounds, which have melting points of 300°C or higher, are preferred. It is believed that the use of a halogen-based flame retardant can suppress halogen elimination at high temperatures and thus suppress a decrease in heat resistance. Furthermore, in fields where halogen-free materials are required, phosphorus-containing flame retardants (phosphorus-based flame retardants) are sometimes used. The phosphorus-based flame retardant is not particularly limited, but examples thereof include phosphate ester-based flame retardants, phosphazene-based flame retardants, bisdiphenylphosphine oxide-based flame retardants, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-based flame retardants, and phosphinate-based flame retardants. Specific examples of phosphate ester-based flame retardants include condensed phosphate esters of dixylenyl phosphate. Specific examples of phosphazene-based flame retardants include phenoxyphosphazene. Specific examples of bisdiphenylphosphine oxide-based flame retardants include xylylenebisdiphenylphosphine oxide. Specific examples of DOPO-based flame retardants include hydrocarbons having two DOPO groups in the molecule (DOPO derivative compounds) and DOPO having a reactive functional group. Specific examples of phosphinate-based flame retardants include metal phosphinates of aluminum dialkylphosphinates. As the flame retardant, each of the exemplified flame retardants may be used alone or in combination of two or more kinds.

[0140] As described above, the resin composition according to this embodiment may contain a reaction initiator. The reaction initiator is not particularly limited as long as it can accelerate the curing reaction of the resin composition, and examples thereof 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-hexyne, and benzoyl peroxide. Examples of organic azo compounds include azobisisobutyronitrile. If necessary, a metal carboxylate or the like can be used in combination. This further accelerates the curing reaction. Among these, α,α'-di(t-butylperoxy)diisopropylbenzene is preferred. Because α,α'-di(t-butylperoxy)diisopropylbenzene has a relatively high reaction initiation temperature, it can suppress acceleration of the curing reaction when curing is not required, such as during prepreg drying, thereby suppressing deterioration in the shelf life of the resin composition. Furthermore, since α,α'-di(t-butylperoxy)diisopropylbenzene has low volatility, it does not volatilize during drying or storage of the prepreg, and has good stability. The reaction initiators may be used alone or in combination of two or more.

[0141] As described above, the 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 resin composition. Specific examples of the curing accelerator include imidazoles and their derivatives, organophosphorus compounds, amines such as secondary amines 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-diaza-bicyclo(5,4,0)undecene-7 (DBU). Examples of the quaternary ammonium salts include tetrabutylammonium bromide. Examples of the organoboron compounds include tetraphenylboron salts such as 2-ethyl-4-methylimidazole tetraphenylborate, and tetra-substituted phosphonium tetra-substituted borates such as tetraphenylphosphonium ethyltriphenylborate. The metal soap refers to a fatty acid metal salt, and may be either a linear fatty acid metal salt or a cyclic fatty acid metal salt. Specific examples of the metal soap include linear fatty acid metal salts and cyclic fatty acid metal salts having 6 to 10 carbon atoms. More specifically, examples of the curing accelerator include aliphatic metal salts composed of linear fatty acids such as stearic acid, lauric acid, ricinoleic acid, and octylic acid, or cyclic fatty acids such as naphthenic acid, and metals such as lithium, magnesium, calcium, barium, copper, and zinc. For example, zinc octylate is included. The curing accelerators may be used alone or in combination of two or more.

[0142] As described above, the resin composition according to this embodiment may contain a silane coupling agent. The silane coupling agent may be contained in the resin composition, or may be contained as a silane coupling agent that has been surface-treated in advance on an inorganic filler contained in the resin composition. Among these, the silane coupling agent is preferably contained as a silane coupling agent that has been surface-treated in advance on an inorganic filler, and it is more preferable to contain the silane coupling agent in advance on an inorganic filler in this way, and further to contain the silane coupling agent in the resin composition. In addition, in the case of a prepreg, the prepreg may contain the silane coupling agent that has been surface-treated in advance on a fibrous substrate. Examples of the silane coupling agent include the same silane coupling agents as those used when surface-treating the inorganic filler described above.

[0143] The resin composition according to this embodiment is a resin composition that can produce a cured product with a high glass transition temperature and a low coefficient of thermal expansion. Furthermore, in order to suppress warping of a semiconductor package having a semiconductor chip mounted on a wiring board, the insulating layer provided on the wiring board is required to have not only a low coefficient of thermal expansion (thermal expansion coefficient) but also low rigidity, and in particular, to have a small change in modulus of elasticity even at high temperatures (such as when heated). The resin composition according to this embodiment not only has a high glass transition temperature and a low coefficient of thermal expansion, but also produces a cured product with a small change in modulus of elasticity even when heated. Therefore, a wiring board having an insulating layer formed using the resin composition according to this embodiment is less likely to warp.

[0144] (Uses) The resin composition is used to produce a prepreg, as described below, and to form a resin layer provided in a resin-coated metal foil or a resin-coated film, and an insulating layer provided in a metal-clad laminate or a wiring board.

[0145] (Production Method) The method for producing the resin composition is not particularly limited, and examples thereof include a method of mixing the maleimide compound (A), the radical polymerizable compound (B), the acrylic block copolymer (C), and, if necessary, components other than the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C) so as to achieve a predetermined content. In addition, in the case of obtaining a varnish-like composition containing an organic solvent, the method described below can be used.

[0146] By using the resin composition according to this embodiment, a prepreg, a metal-clad laminate, a wiring board, a resin-coated metal foil, and a resin-coated film can be obtained as follows.

[0147] [Prepreg] FIG. 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention.

[0148] 1, the prepreg 1 according to this embodiment comprises the resin composition or a semi-cured product of the resin composition 2, and a fibrous base material 3. This prepreg 1 comprises the resin composition or a semi-cured product of the resin composition 2, and the fibrous base material 3 present in the resin composition or the semi-cured product of the resin composition 2.

[0149] In this embodiment, the semi-cured product refers to a resin composition that has been partially cured to the extent that it can be further cured. That is, the semi-cured product refers to a resin composition that has been semi-cured (B-staged). For example, when a resin composition is heated, the viscosity initially gradually decreases, and then curing begins, and the viscosity gradually increases. In such a case, the semi-cured state may refer to a state between when the viscosity starts to increase and when the composition is completely cured.

[0150] The prepreg obtained using the resin composition according to this embodiment may comprise a semi-cured product of the resin composition as described above, or may comprise the uncured resin composition itself. That is, it may be a prepreg comprising a semi-cured product of the resin composition (the resin composition in B stage) and a fibrous base material, or a prepreg comprising the resin composition before curing (the resin composition in A stage) and a fibrous base material. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried.

[0151] When producing the prepreg, the resin composition 2 is often prepared in a varnish form and used to impregnate the fibrous base material 3, which is a base material for forming the prepreg. That is, the resin composition 2 is usually often a resin varnish prepared in a varnish form. Such a varnish-like resin composition (resin varnish) is prepared, for example, as follows.

[0152] First, each component that is soluble in an organic solvent is added to the organic solvent and dissolved. Heating may be performed as necessary. Then, components that are insoluble in the organic solvent are added as needed, and the mixture is dispersed using a ball mill, bead mill, planetary mixer, roll mill, or the like until a predetermined dispersion state is achieved, thereby preparing a varnish-like resin composition. The organic solvent used here is not particularly limited as long as it dissolves the organic components and resin components in the resin composition and does not inhibit the curing reaction. Specific examples include toluene and methyl ethyl ketone (MEK).

[0153] Specific examples of the fibrous substrate include glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. Glass cloth can be used to obtain a laminate with excellent mechanical strength, and flattened glass cloth is particularly preferred. A specific example of the flattening process is a method in which glass cloth is continuously pressed with a press roll at an appropriate pressure to compress the yarns flat. The thickness of commonly used fibrous substrates is, for example, 0.01 mm or more and 0.3 mm or less. The glass fibers constituting the glass cloth are not particularly limited, and examples include Q glass, NE glass, E glass, S glass, T glass, L glass, and L2 glass. The surface of the fibrous substrate may be treated with a silane coupling agent. The silane coupling agent is not particularly limited, but examples thereof include silane coupling agents having at least one group selected from the group consisting of a vinyl group, an acryloyl group, a methacryloyl group, a styryl group, an amino group, and an epoxy group in the molecule.

[0154] The method for producing the prepreg is not particularly limited as long as it can produce the prepreg. Specifically, when producing the prepreg, the resin composition according to the present embodiment is often prepared in the form of a varnish, as described above, and used as a resin varnish.

[0155] Specific examples of methods for producing the prepreg 1 include a method in which the resin composition 2, for example, a resin composition 2 prepared in a varnish form, is impregnated into a fibrous substrate 3, followed by drying. The resin composition 2 is impregnated into the fibrous substrate 3 by immersion, coating, or the like. Impregnation can be repeated multiple times as necessary. In this case, by repeating the impregnation using multiple resin compositions with different compositions and concentrations, it is also possible to adjust the final composition and impregnation amount to the desired one.

[0156] The fibrous substrate 3 impregnated with the resin composition (resin varnish) 2 is heated under desired conditions, for example, at 40°C to 180°C for 1 minute to 10 minutes. This heating process results in a prepreg 1 in an uncured (A-stage) or semi-cured (B-stage) state. The heating process also volatilizes the organic solvent from the resin varnish, reducing or eliminating the organic solvent.

[0157] [Metal-clad laminate] FIG. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate 11 according to an embodiment of the present invention.

[0158] As shown in FIG. 2 , the metal-clad laminate 11 according to this embodiment includes an insulating layer 12 containing a cured product of the resin composition and a metal foil 13 disposed on the insulating layer 12. Examples of the metal-clad laminate 11 include a metal-clad laminate composed of an insulating layer 12 containing a cured product of the prepreg 1 shown in FIG. 1 and a metal foil 13 laminated together with the insulating layer 12. The insulating layer 12 may be composed of a cured product of the resin composition or a cured product of the prepreg. The thickness of the metal foil 13 varies depending on the performance required of the final wiring board and is not particularly limited. The thickness of the metal foil 13 can be appropriately set depending on the desired purpose, and is preferably, for example, 0.2 to 70 μm. Examples of the metal foil 13 include copper foil and aluminum foil. When the metal foil is thin, it may be a carrier-attached copper foil equipped with a release layer and a carrier to improve handling.

[0159] The method for producing the metal-clad laminate 11 is not particularly limited as long as it can produce the metal-clad laminate 11. Specifically, a method for producing the metal-clad laminate 11 using the prepreg 1 can be used. Examples of such a method include stacking one or more prepregs 1, placing a metal foil 13 such as copper foil on both sides or one side of the prepreg 1, and then heat-pressing and molding the metal foil 13 and the prepreg 1 to form an integrated laminate. That is, the metal-clad laminate 11 can be obtained by laminating the metal foil 13 on the prepreg 1 and then heat-pressing and molding the laminate. The heat-pressing conditions can be appropriately set depending on the thickness of the metal-clad laminate 11, the type of resin composition contained in the prepreg 1, and other factors. For example, the temperature can be 170 to 230°C, the pressure can be 2 to 5 MPa, and the time can be 60 to 150 minutes. The metal-clad laminate can also be produced without using a prepreg. For example, a method may be used in which a varnish-like resin composition is applied onto a metal foil to form a layer containing the resin composition on the metal foil, and then the layer is heated and pressed.

[0160] [Wiring Board] FIG. 3 is a schematic cross-sectional view showing an example of a wiring board 21 according to an embodiment of the present invention.

[0161] As shown in Fig. 3, wiring board 21 according to this embodiment has insulating layer 12 containing a cured product of the resin composition, and wiring 14 provided on insulating layer 12. Examples of wiring board 21 include a wiring board configured from insulating layer 12 used by curing prepreg 1 shown in Fig. 1, and wiring 14 laminated together with insulating layer 12 and formed by partially removing metal foil 13. Furthermore, insulating layer 12 may be made of a cured product of the resin composition, or may be made of a cured product of the prepreg.

[0162] The method for manufacturing the wiring board 21 is not particularly limited as long as the wiring board 21 can be manufactured. Specific examples include a method of manufacturing the wiring board 21 using the prepreg 1. Examples of this method include a method of manufacturing the wiring board 21 in which wiring is provided as a circuit on the surface of the insulating layer 12 by etching the metal foil 13 on the surface of the metal-clad laminate 11 manufactured as described above. That is, the wiring board 21 is obtained by forming a circuit by partially removing the metal foil 13 on the surface of the metal-clad laminate 11. In addition to the above methods, examples of the method for forming a circuit include circuit formation by a semi-additive process (SAP) or a modified semi-additive process (MSAP).

[0163] [Resin-Coated Metal Foil] FIG. 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil 31 according to this embodiment.

[0164] As shown in Fig. 4, the resin-coated metal foil 31 according to this embodiment comprises a resin layer 32 containing the resin composition or a semi-cured product of the resin composition, and a metal foil 13. The resin-coated metal foil 31 has the metal foil 13 on the surface of the resin layer 32. That is, the resin-coated metal foil 31 comprises the resin layer 32 and the metal foil 13 laminated together with the resin layer 32. The resin-coated metal foil 31 may also comprise another layer between the resin layer 32 and the metal foil 13.

[0165] The resin layer 32 may contain a semi-cured product of the resin composition as described above, or may contain the uncured resin composition. That is, the resin-coated metal foil 31 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition in B-stage) and a metal foil, or a resin layer containing the resin composition before curing (the resin composition in A-stage) and a metal foil. The resin layer may contain the resin composition or a semi-cured product of the resin composition, and may or may not contain a fibrous substrate. The resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried. The fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0166] The metal foil may be any metal foil used in a metal-clad laminate or a resin-coated metal foil, and examples of the metal foil include copper foil and aluminum foil.

[0167] The resin-coated metal foil 31 may be provided with a cover film or the like as necessary. By providing a cover film, it is possible to prevent the inclusion of foreign matter, etc. The cover film is not particularly limited, but examples thereof include polyolefin films, polyester films, polymethylpentene films, and films formed by providing these films with a release agent layer.

[0168] The method for producing the resin-coated metal foil 31 is not particularly limited as long as the resin-coated metal foil 31 can be produced. Examples of the method for producing the resin-coated metal foil 31 include a method of applying the varnish-like resin composition (resin varnish) to the metal foil 13 and heating the applied resin composition. The varnish-like resin composition is applied to the metal foil 13 using, for example, a bar coater. The applied resin composition is heated, for example, at 40°C or higher and 180°C or lower for 0.1 minutes or longer and 10 minutes or shorter. The heated resin composition is formed on the metal foil 13 as an uncured resin layer 32. The heating volatilizes the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0169] [Resin-Coated Film] FIG. 5 is a schematic cross-sectional view showing an example of a resin-coated film 41 according to this embodiment.

[0170] 5 , the resin-coated film 41 according to this embodiment includes a resin layer 42 containing the resin composition or a semi-cured product of the resin composition, and a support film 43. The resin-coated film 41 includes the resin layer 42 and the support film 43 laminated together with the resin layer 42. The resin-coated film 41 may also include another layer between the resin layer 42 and the support film 43.

[0171] The resin layer 42 may contain a semi-cured product of the resin composition as described above, or may contain the uncured resin composition. That is, the resin-coated film 41 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition in B-stage) and a support film, or a resin-coated film comprising a resin layer containing the resin composition before curing (the resin composition in A-stage) and a support film. The resin layer may contain the resin composition or a semi-cured product of the resin composition, and may or may not contain a fibrous substrate. The resin composition or the semi-cured product of the resin composition may be obtained by drying or heat-drying the resin composition. The fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0172] Any support film used for a resin-coated film can be used without limitation as the support film 43. Examples of the support film include electrically insulating films such as polyester film, polyethylene terephthalate (PET) film, polyimide film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, polyamide film, polycarbonate film, and polyarylate film.

[0173] The resin-coated film 41 may be provided with a cover film or the like as necessary. By providing a cover film, it is possible to prevent the inclusion of foreign matter, etc. The cover film is not particularly limited, but examples thereof include a polyolefin film, a polyester film, and a polymethylpentene film.

[0174] The support film and the cover film may be subjected to surface treatment such as matte treatment, corona treatment, release treatment, and roughening treatment, if necessary.

[0175] The method for producing the resin-coated film 41 is not particularly limited as long as it can produce the resin-coated film 41. Examples of methods for producing the resin-coated film 41 include a method in which the varnish-like resin composition (resin varnish) is applied to a support film 43 and heated. The varnish-like resin composition is applied to the support film 43 using, for example, a bar coater. The applied resin composition is heated, for example, at 40°C or higher and 180°C or lower for 0.1 minutes or longer and 10 minutes or shorter. The heated resin composition is formed on the support film 43 as an uncured resin layer 42. The heating volatilizes the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0176] When cured, the resin composition according to this embodiment becomes a cured product with a high glass transition temperature and a low thermal expansion coefficient. Therefore, when cured, the prepreg becomes a cured product with a high glass transition temperature and a low thermal expansion coefficient. The resin-coated metal foil and the resin-coated film are, respectively, resin-coated metal foil and resin-coated film, each having a resin layer that becomes an insulating layer containing the cured product when cured. The metal-clad laminate and the wiring board are, respectively, metal-clad laminate and wiring board, each having an insulating layer containing the cured product. The prepreg, the resin-coated film, the resin-coated metal foil, and the metal-clad laminate can be used to manufacture the wiring board, for example, to manufacture a multilayer wiring board. For example, a multilayer wiring board can be manufactured by laminating the resin-coated film on a wiring board and then peeling off the support film, or by laminating the resin-coated film on a wiring board after peeling off the support film. For example, a multilayer wiring board can be manufactured by laminating the resin-coated metal foil on a wiring board. In this way, a multilayer wiring board having an insulating layer containing the cured product can be manufactured by using the resin-coated film, resin-coated metal foil, etc. The wiring board obtained using the prepreg, resin-coated film, resin-coated metal foil, and metal-clad laminate is a wiring board having an insulating layer containing a cured product with a high glass transition temperature and a low thermal expansion coefficient.

[0177] As described above, this specification discloses various aspects of the technology, the main technologies of which are summarized below.

[0178] A resin composition according to a first aspect of the present invention includes a maleimide compound (A) having in the molecule at least one of an indane structure and an arylene structure bonded and oriented at a meta position, a radically polymerizable compound (B), and an acrylic block copolymer (C) including a structural unit (c1) represented by formula (1) and a structural unit (c2) represented by formula (2), wherein the acrylic block copolymer (C) has a number average molecular weight of 10,000 or more and a content of the structural unit (c1) of 20 mass% or less relative to the mass of the acrylic block copolymer (C).

[0179] A resin composition according to a second aspect of the present invention is the resin composition according to the first aspect of the present invention, wherein the radical polymerizable compound (B) comprises at least one of a benzoxazine compound (B1) having an alkenyl group in the molecule and a hydrocarbon compound (B2) having a reactive carbon-carbon unsaturated group in the molecule.

[0180] A resin composition according to a third aspect of the present invention is the resin composition according to the first or second aspect of the present invention, wherein a content ratio of the maleimide compound (A) to the radical polymerizable compound (B) is 50:50 to 90:10 in mass ratio.

[0181] A resin composition according to a fourth aspect of the present invention is the resin composition according to any one of the first to third aspects of the present invention, wherein the content of the acrylic block copolymer (C) is 5 to 40 parts by mass per 100 parts by mass of the total of the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C).

[0182] A resin composition according to a fifth aspect of the present invention is the resin composition according to any one of the first to fourth aspects of the present invention, wherein the content of the radical polymerizable compound (B) is 10 to 50 parts by mass per 100 parts by mass of the total of the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C).

[0183] A resin composition according to a sixth aspect of the present invention is the resin composition according to any one of the first to fifth aspects of the present invention, further comprising a styrene-based elastomer (D).

[0184] A resin composition according to a seventh aspect of the present invention is the resin composition according to any one of the first to sixth aspects of the present invention, wherein the maleimide compound (A) comprises a maleimide compound (A1-1) represented by formula (3).

[0185] A resin composition according to an eighth aspect of the present invention is a resin composition according to any one of the first to seventh aspects of the present invention, wherein the indane structure includes a structure represented by formula (4).

[0186] A prepreg according to a ninth aspect of the present invention is a prepreg comprising the resin composition according to any one of the first to eighth aspects of the present invention or a semi-cured product of the resin composition, and a fibrous base material.

[0187] A resin-coated film according to a tenth aspect of the present invention is a resin-coated film comprising a resin layer containing the resin composition according to any one of the first to eighth aspects of the present invention or a semi-cured product of the resin composition, and a support film.

[0188] The resin-coated metal foil according to an eleventh aspect of the present invention is a resin-coated metal foil comprising a resin layer containing the resin composition according to any one of the first to eighth aspects of the present invention or a semi-cured product of the resin composition, and a metal foil.

[0189] A metal-clad laminate according to a twelfth aspect of the present invention is a metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to any one of the first to eighth aspects of the present invention, and a metal foil.

[0190] A metal-clad laminate according to a thirteenth aspect of the present invention is a metal-clad laminate comprising an insulating layer containing a cured product of the prepreg according to the ninth aspect of the present invention and a metal foil.

[0191] A wiring board according to a fourteenth aspect of the present invention is a wiring board comprising an insulating layer containing a cured product of the resin composition according to any one of the first to eighth aspects of the present invention, and wiring.

[0192] A wiring board according to a fifteenth aspect of the present invention is a wiring board comprising an insulating layer containing a cured product of the prepreg according to the ninth aspect of the present invention and wiring.

[0193] According to the present invention, there is provided a resin composition that can give a cured product having a high glass transition temperature and a low thermal expansion coefficient. Furthermore, according to the present invention, there are provided a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using the resin composition.

[0194] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0195] Examples 1 to 5 and Comparative Examples 1 to 6 In these examples, each component used in preparing the resin composition will be described.

[0196] (Maleimide Compounds) Maleimide compound 1: A maleimide compound having an arylene structure substituted at the meta position in the molecule (solid content in MIR-5000-60T (a toluene solution of a maleimide compound) manufactured by Nippon Kayaku Co., Ltd., a maleimide compound represented by the formula (6) above, maleimide equivalent 260 g / mol) Maleimide compound 2: A maleimide compound having an indane structure and an arylene structure oriented and bonded at the meta position in the molecule. Specifically, this maleimide compound was synthesized as follows, and is a maleimide compound represented by the formula (8) above.

[0197] First, 48.5 g (0.4 mol) of 2,6-dimethylaniline, 272.0 g (1.4 mol) of α,α'-dihydroxy-1,3-diisopropylbenzene, 280 g of xylene, and 70 g of activated clay were charged into a 1 L flask equipped with a thermometer, a condenser, a Dean-Stark tube, and a stirrer, and the mixture was heated to 120 °C with stirring. Furthermore, the temperature was raised to 210 °C while removing the distillate water using a Dean-Stark tube. This allowed for a reaction for 6 hours. The mixture was then cooled to 140 °C, and 145.4 g (1.2 mol) of 2,6-dimethylaniline was charged, followed by heating to 220 °C. This allowed for a reaction for 3 hours. After the reaction, the mixture was air-cooled to 100 °C, diluted with 300 g of toluene, and the activated clay was removed by filtration. Low-molecular-weight substances such as the solvent and unreacted materials were distilled off under reduced pressure, yielding 345.2 g of a solid. The obtained solid was an amine compound represented by the following formula (35) (amine equivalent: 348, softening point: 71° C.).

[0198] In formula (35), n represents 0.95 to 10.

[0199] Next, 131.8 g (1.3 mol) of maleic anhydride and 700 g of toluene were charged into a 2 L flask equipped with a thermometer, a condenser, a Dean-Stark tube, and a stirrer, and the mixture was stirred at room temperature. Subsequently, a mixed solution of 345.2 g of the amine compound represented by formula (35) and 175 g of DMF was added dropwise over 1 hour. After the completion of the dropwise addition, the mixture was stirred at room temperature for an additional 2 hours to allow the reaction to proceed. Subsequently, 37.1 g of p-toluenesulfonic acid monohydrate was added, and the reaction solution was heated under reflux. The azeotropic water and toluene were cooled and separated, and then only the toluene was returned to the system, allowing the dehydration reaction to proceed for 8 hours. After air-cooling to room temperature, the mixture was concentrated under reduced pressure, and the brown solution was dissolved in 600 g of ethyl acetate. The solution was washed three times with 150 g of ion-exchanged water and three times with 150 g of a 2% aqueous sodium bicarbonate solution, dried over sodium sulfate, and then concentrated under reduced pressure. The resulting reaction product was vacuum-dried at 80°C for 4 hours, yielding 407.6 g of a solid. The obtained solid was analyzed by FD-MS spectrum, GPC, etc., and was found to be a maleimide compound represented by the formula (8) (a maleimide compound in which the amine of the amine compound represented by the formula (35) was modified to a maleimide, benzene ring equivalent: 153 g / mol, maleimide equivalent: 428 g / mol).

[0200] Maleimide compound 3: 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide (BMI-5100, manufactured by Daiwa Chemical Industry Co., Ltd., bismaleimide compound, maleimide equivalent: 221 g / mol)

[0201] (Radical polymerizable compound) Benzoxazine compound: a benzoxazine compound having an allyl group in the molecule (represented by the formula (13) above, R ３ and R ４ is an allyl group, X is a methylene group, and b and c are 1, a benzoxazine compound ALPd manufactured by Shikoku Chemicals Corporation

[0202] (Hydrocarbon Compound) Hydrocarbon compound: A hydrocarbon compound represented by the formula (15).

[0203] Specifically, it is a hydrocarbon compound synthesized as follows.

[0204] Synthesis Example 1 296 parts by mass of 2-bromoethylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd.), 70 parts by mass of α,α'-dichloro-p-xylene (manufactured by Tokyo Chemical Industry Co., Ltd.), and 18.4 parts by mass of methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were charged into a flask equipped with a thermometer, a condenser, and a stirrer, and the mixture was reacted at 130°C for 8 hours. After the reaction, the mixture was allowed to cool, and the reaction solution obtained by the reaction was neutralized with an aqueous sodium hydroxide solution, extracted with 1200 parts by mass of toluene, and the organic layer was washed five times with 100 parts by mass of water. The solvent and excess 2-bromoethylbenzene were distilled off under heating and reduced pressure, yielding 160 parts by mass of an olefin compound precursor (BEB-1) having a 2-bromoethylbenzene structure as a liquid resin (Mn: 538, Mw: 649). The repeating unit d was 1.7. Furthermore, the resulting compound １ H-NMR chart (DMSO-d ６ ), signals derived from bromoethyl groups were observed at 2.95-3.15 ppm and 3.60-3.75 ppm.

[0205] (Synthesis Example 2) Next, 22 parts by mass of BEB-1 obtained in Synthesis Example 1, 50 parts by mass of toluene, 150 parts by mass of dimethyl sulfoxide, 15 parts by mass of water, and 5.4 parts by mass of sodium hydroxide were added to a flask equipped with a thermometer, a condenser, and a stirrer, and the mixture was reacted at 40°C for 5 hours. After the reaction, the mixture was allowed to cool, and then 100 parts by mass of toluene was added, and the organic layer was washed five times with 100 parts by mass of water. The solvent was distilled off under heating and reduced pressure, yielding 13 parts by mass of a liquid olefin compound having a styrene structure as a functional group (Mn: 432, Mw: 575). The repeating unit d was 1.7. In addition, the obtained compound １ H-NMR data (DMSO-d ６ ), signals derived from vinyl groups were observed at 5.10-5.30 ppm, 5.50-5.85 ppm, and 6.60-6.80 ppm.

[0206] The resulting compound (liquid olefin compound) was the hydrocarbon compound represented by the formula (15).

[0207] The weight average molecular weight (Mw) and number average molecular weight (Mn) used in Synthesis Example 1 and Synthesis Example 2 were values ​​determined by the following analytical method.

[0208] (Analysis Method) Calculation was performed in terms of polystyrene using a polystyrene standard solution.

[0209] GPC: DGU-20A3R, LC-20AD, SIL-20AHT, RID-20A, SPD-20A, CTO-2, CBM-20A (all manufactured by Shimadzu Corporation) Column: Shodex KF-603, KF-602x2, KF-601x2) Eluent: Tetrahydrofuran Flow rate: 0.5 ml / min. Column temperature: 40°C Detection: RI (differential refractometer)

[0210] (Acrylic Block Copolymers) Acrylic Block Copolymer 1: A triblock copolymer of methyl methacrylate, n-butyl acrylate, and methyl methacrylate, containing 10% by mass of structural units derived from methyl methacrylate (Kuraray Co., Ltd.'s Kuraray LA2114, number average molecular weight Mn: 12,000, liquid at 25°C). Acrylic Block Copolymer 2: A triblock copolymer of methyl methacrylate, n-butyl acrylate, and methyl methacrylate, containing 15% by mass of structural units derived from methyl methacrylate (Kuraray Co., Ltd.'s Kuraray LA3320, number average molecular weight Mn: 47,000, solid at 25°C). Acrylic Block Copolymer 3: A triblock copolymer of methyl methacrylate, n-butyl acrylate, and methyl methacrylate, containing 13% by mass of structural units derived from methyl methacrylate (Kuraray Co., Ltd.'s Kuraray LA3710, number average molecular weight Mn: 190,000, solid at 25°C). Acrylic block copolymer 4: a triblock copolymer of methyl methacrylate, n-butyl acrylate, and methyl methacrylate, having a content of structural units derived from methyl methacrylate of 50% by mass (CLARITY LA4285 manufactured by Kuraray Co., Ltd., number average molecular weight Mn: 33,000). Acrylic random copolymer: a random copolymer containing 4% by mass of structural units represented by the following formula (36), 10% by mass of structural units represented by the following formula (37), 57% by mass of structural units represented by the following formula (38), 6% by mass of structural units represented by the following formula (39), and 22% by mass of structural units represented by the following formula (40) (PASR001 manufactured by Nagase ChemteX Corporation).

[0211]

[0212]

[0213]

[0214]

[0215]

[0216] Styrene-based polymer: hydrogenated styrene (ethylene butylene) styrene copolymer (Tuftec H1041 manufactured by Asahi Kasei Corporation, a copolymer having repeating units represented by the above formulas (18) to (20), (27), and (28) in the molecule, weight average molecular weight: 80,000)

[0217] (Organic Component) Epoxy group-containing polybutadiene compound: a polybutadiene compound having an epoxy group in the molecule (JP-100 manufactured by Nippon Soda Co., Ltd., an epoxidized polybutadiene in which epoxy groups have been partially introduced by oxidizing the vinyl groups of 1,2-polybutadiene)

[0218] (Reaction initiator) Reaction initiator: α,α'-di(t-butylperoxy)diisopropylbenzene (PBP) (Perbutyl P manufactured by NOF Corporation)

[0219] (Curing accelerator) Curing accelerator: 2-ethyl-4-methylimidazole (2E4MZ) (2E4MZ manufactured by Shikoku Chemicals Corporation)

[0220] (Inorganic filler) Silica: silica particles surface-treated with a silane coupling agent having a phenylamino group in the molecule (SC2500-SXJ manufactured by Admatechs Co., Ltd.) Zinc molybdate (Z4SX-A1 manufactured by Admatechs Co., Ltd.)

[0221] [Preparation Method] First, the components other than the inorganic filler were added to a mixed solvent of toluene and methyl ethyl ketone (MEK) (mass ratio of approximately 2:1) so that the solids concentration was 50 mass% in the composition (parts by mass) shown in Table 1, and mixed. The resulting mixture was stirred for 60 minutes. Thereafter, if an inorganic filler was included, the inorganic filler was added to the resulting mixture in the composition (parts by mass) shown in Table 1, and dispersed using a bead mill. This resulted in a varnish-like resin composition (varnish).

[0222] Next, a prepreg was obtained as follows.

[0223] The resulting varnish was impregnated into a fibrous substrate (glass cloth: #2118 type T-glass manufactured by Nitto Boseki Co., Ltd.) and then heated and dried at 130°C for 3 minutes to produce a prepreg. The content of the components that constitute the resin by the curing reaction (resin content) relative to the prepreg was adjusted to approximately 43 mass%. Furthermore, the thickness after curing was adjusted to 103 μm.

[0224] An evaluation substrate (metal-clad laminate) was obtained as follows.

[0225] Ten sheets of the obtained prepreg were stacked, and 12 μm thick copper foil (3EC-VLP manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on both sides. This was used as a pressure body, and heated to a temperature of 220°C at a temperature increase rate of 3°C / min, and then heated and pressed at 220°C for 120 minutes under a pressure of 3 MPa, thereby obtaining an evaluation substrate (metal-clad laminate) with copper foil bonded to both sides and a resin layer thickness of approximately 1030 μm.

[0226] The evaluation substrate prepared as described above was evaluated by the following method.

[0227] [Glass Transition Temperature (Tg)] An unclad plate obtained by removing the copper foil from the evaluation substrate (metal-clad laminate) by etching was used as a test piece, and the Tg of the cured resin composition was measured using a viscoelasticity spectrometer "DMS6100" manufactured by Seiko Instruments Inc. At this time, dynamic viscoelasticity measurement (DMA) was performed with a bending module at a frequency of 10 Hz, and the temperature at which tan δ showed a maximum when the temperature was raised from room temperature to 340°C at a heating rate of 5°C / min was taken as Tg (°C). If the measured glass transition temperature was 270°C or higher, it was judged to be "passed."

[0228] [Flexural Modulus and Elastic Modulus Ratio] An unclad plate obtained by etching the copper foil from the evaluation substrate (metal-clad laminate) was used as a test piece, and the flexural modulus (storage modulus) of the cured resin composition was measured using a viscoelasticity spectrometer "DMS6100" manufactured by Seiko Instruments Inc. At this time, dynamic viscoelasticity measurement (DMA) was performed with a bending module at a frequency of 10 Hz, and the flexural modulus at 30 ° C. and the flexural modulus at 260 ° C. were measured when the temperature was raised from room temperature to 340 ° C. at a heating rate of 5 ° C. / min. Then, the ratio of the flexural modulus at 260 ° C. to the flexural modulus at 30 ° C. (flexural modulus at 260 ° C. / flexural modulus at 30 ° C.) was calculated. This ratio was taken as the elastic modulus ratio. If this elastic modulus ratio was 0.65 or more, it was judged to be "passed."

[0229] [Thermal expansion coefficient (50-100 ° C)] An unclad plate obtained by etching the copper foil from the evaluation substrate (metal-clad laminate) was used as a test specimen. The thermal expansion coefficient in the plane direction (tensile 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 Inc.) was used for the measurement in compression mode. In order to eliminate the influence of thermal distortion of the test specimen, the test specimen was pulled in the Y direction with a load of 10 g, and the temperature was raised from 30 ° C to 320 ° C at a heating rate of 10 ° C / min, and then cooled to room temperature. Then, the test specimen was pulled in the Y direction with a load of 10 g, and the temperature was raised from 30 ° C to 320 ° C at a heating rate of 10 ° C / min. A temperature displacement chart was obtained during this heating period. The average thermal expansion coefficient from 50 to 100°C was then calculated from the temperature change chart obtained at this time. The smaller this average thermal expansion coefficient (Y-CTE 50-100°C) is, the more favorable the result is, and in this test, a value of 5.5 ppm / °C or less was judged to be "pass."

[0230] [Coefficient of thermal expansion (50 to 260°C)] The average coefficient of thermal expansion from 50 to 260°C was calculated from the temperature change chart obtained during the measurement of the coefficient of thermal expansion (CTE)-1. The smaller this average coefficient of thermal expansion (Y-CTE 50-260°C) is, the more favorable the result is, and in this test, a value of 6.0 ppm / °C or less is considered to be "pass."

[0231] The results of the above evaluations, together with the formulation of the resin composition, are shown in Table 1. In Table 1, ">310" in the glass transition temperature column indicates that the temperature is greater than 310°C.

[0232]

[0233] As can be seen from Table 1, in the resin composition containing a maleimide compound (A) having in its molecule at least one of an indane structure and an arylene structure oriented and bonded at the meta position [the maleimide compound (A) containing at least one selected from the group consisting of the maleimide compound (A1), the maleimide compound (A2), and the maleimide compound (A3)] and a radically polymerizable compound (B), when an acrylic block copolymer (C) having a number average molecular weight of 10,000 or more and containing 20 mass% or less of the structural unit (c1) and the structural unit (c2) was contained (Examples 1 to 9), compared to when no acrylic block copolymer was contained (Comparative Example 1), when an acrylic random copolymer was contained instead of the acrylic block copolymer (Comparative Example 2), and when an acrylic block copolymer different from the acrylic block copolymer (C) was contained (Comparative Example 3), a resin composition was obtained that became a cured product with a high glass transition temperature and a low thermal expansion coefficient. Furthermore, it was found that the cured products obtained from the resin compositions of Examples 1 to 9 had a low elastic modulus ratio, and therefore showed little change in elastic modulus even at high temperatures.

[0234] In addition to the glass transition temperature and the thermal expansion coefficient, the resin composition containing the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C) was also examined (specifically, the copper foil peel strength).

[0235] [Copper Foil Peel Strength] The copper foil was peeled from the evaluation substrate (metal-clad laminate), and the peel strength at this time was measured in accordance with JIS C 6481 (1996). Specifically, the copper foil was peeled from the evaluation substrate at a rate of 50 mm / min using a tensile tester, and the peel strength (N / mm) at this time was measured. This peel strength is the copper foil peel strength, and it can be seen that the higher this is, the higher the adhesion of the metal foil (copper foil).

[0236] The results are shown in Table 2.

[0237]

[0238] As described above, Table 1 shows that when the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C) are contained (Examples 1 to 9), resin compositions are obtained that have a high glass transition temperature and a low thermal expansion coefficient and elastic modulus ratio. Furthermore, a comparison of Examples 5 to 7 in Table 2 shows that a lower content of the acrylic block copolymer (C) and a higher content of the maleimide compound (A) and the radical polymerizable compound (B) results in higher copper foil peel strength. Example 2, which contains an acrylic block copolymer having a number-average molecular weight of 30,000 or more (40,000 or more) as the acrylic block copolymer (C), exhibits a lower thermal expansion coefficient and higher copper foil peel strength than Example 1, which contains an acrylic block copolymer having a number-average molecular weight of less than 30,000 (less than 40,000). As described above, Example 1, which contains an acrylic block copolymer (C) having a number-average molecular weight of less than 30,000 (less than 40,000), not only has a high glass transition temperature but also a low thermal expansion coefficient. However, while the thermal expansion coefficient is relatively high among the examples, the copper foil peel strength is higher than that of Example 2. This indicates that the acrylic block copolymer (C) preferably has a number-average molecular weight of 30,000 or more (40,000 or more). Furthermore, the acrylic block copolymer (C) used in Example 2 is solid at 25°C, while the acrylic block copolymer (C) used in Example 1 is liquid at 25°C. This indicates that the acrylic block copolymer (C) is preferably solid at 25°C. Example 9, which contained a benzoxazine compound having an allyl group in the molecule as the radical polymerizable compound (B), not only had a high glass transition temperature and a low thermal expansion coefficient, but also had a higher copper foil peel strength despite having a higher content of the acrylic block copolymer (C) than Example 3, which contained the hydrocarbon compound. This demonstrates that Example 9, which contained a benzoxazine compound having an allyl group in the molecule, was able to achieve both a high glass transition temperature, a low thermal expansion coefficient, and high adhesion.In this respect, it has been found that the radical polymerizable compound (B) is preferably a benzoxazine compound having an allyl group in the molecule (a benzoxazine compound having an alkenyl group in the molecule).

[0239] This application is based on Japanese Patent Application No. 2023-166137 filed on September 27, 2023, the contents of which are incorporated herein by reference.

[0240] In order to express the present invention, the present invention has been properly and sufficiently described through the embodiments in the above, but it should be recognized that those skilled in the art can easily change and / or improve the above-mentioned embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that causes departure from the scope of the claims described in the claims, such changes or improvements are interpreted as being included in the scope of the claims.

[0241] The present invention provides a resin composition that can give a cured product having a high glass transition temperature and a low thermal expansion coefficient. The present invention also provides a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using the resin composition.

Claims

1. A resin composition comprising: a maleimide compound (A) having in the molecule at least one of an indane structure and an arylene structure oriented and bonded at the meta position; a radically polymerizable compound (B); and an acrylic block copolymer (C) containing a structural unit (c1) represented by the following formula (1) and a structural unit (c2) represented by the following formula (2), wherein the acrylic block copolymer (C) has a number average molecular weight of 10,000 or more and a content of the structural unit (c1) is 20 mass% or less relative to the acrylic block copolymer (C). [In formula (2), Y represents a hydrocarbon group having 4 or more carbon atoms.] 2. The resin composition according to claim 1, wherein the radical polymerizable compound (B) comprises at least one of a benzoxazine compound (B1) having an alkenyl group in the molecule and a hydrocarbon compound (B2) having a reactive carbon-carbon unsaturated group in the molecule.

3. The resin composition according to claim 1, wherein the content ratio of the maleimide compound (A) to the radical polymerizable compound (B) is 50:50 to 90:10 by mass.

4. The resin composition according to claim 1, wherein the content of the acrylic block copolymer (C) is 5 to 40 parts by mass per 100 parts by mass of the total of the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C).

5. The resin composition according to claim 1, wherein the content of the radical polymerizable compound (B) is 10 to 50 parts by mass per 100 parts by mass in total of the maleimide compound (A), the radical polymerizable compound (B), and the acrylic block copolymer (C).

6. The resin composition according to claim 1, further comprising a styrene-based polymer (D).

7. The resin composition according to claim 1, wherein the maleimide compound (A) comprises a maleimide compound (A1-1) represented by the following formula (3): [In formula (3), Ar represents an arylene group bonded to the meta position, and 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, and s represents 1 to 5.

8. The resin composition according to claim 1, wherein the indane structure includes a structure represented by the following formula (4): [In formula (4), each Rb independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy 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, and r represents 0 to 3.] 9. A prepreg comprising the resin composition according to any one of claims 1 to 8 or a semi-cured product of said resin composition and a fibrous base material.

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

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

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

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

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

15. A wiring board comprising an insulating layer containing the cured product of the prepreg according to claim 9 and wiring.

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