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

Abstract

One aspect of the present invention is a resin composition comprising: a maleimide compound (A) which has a maleimide equivalent of 500 g / eq. or less, has a solid form at 25℃, and can be dissolved at any concentration ranging from 40% by mass or more and less than 100% by mass in a mixture of at least one component selected from the group consisting of toluene and methyl ethyl ketone and the maleimide compound at 25℃; and a polymerizable compound (B) which has a carbon-carbon unsaturated double bond in the molecule thereof, and in which the ratio of the total mass of hetero atoms to the total mass of all of constituent elements is 15% by mass or less.

Description

[Technical Field]

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

[0002] As the amount of information processed increases in various electronic devices, advances in packaging technologies, such as higher integration of semiconductor devices, higher wiring density, 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 the insulating layers of wiring boards used in various electronic devices are required to have low relative permittivity and dielectric loss tangent in order to increase signal transmission speed and reduce loss during signal transmission. Examples of such substrate materials include resin compositions containing thermoplastic elastomers.

[0003] Molding materials such as substrate materials are required to have not only excellent low dielectric properties but also excellent heat resistance, etc. For this reason, it is considered to use maleimide resin, which is known to have high heat resistance, as a substrate material.

[0004] Examples of resin compositions containing such maleimide resins and thermoplastic elastomers include the resin composition described in Patent Document 1. Patent Document 1 describes a thermosetting resin composition containing an addition reaction product of a maleimide compound and an amine compound, a thermoplastic elastomer, and a copolymer resin containing structural units derived from a carboxylic acid anhydride, such as structural units derived from maleic anhydride, and structural units derived from an aromatic vinyl compound. Patent Document 1 discloses that a thermosetting resin composition having excellent heat resistance, low thermal expansion, a low dielectric constant, and a low dielectric loss tangent can be obtained.

[0005] Metal-clad laminates and resin-coated metal foils used in manufacturing wiring boards and the like have not only an insulating layer but also a metal foil on the insulating layer. Similarly, wiring boards also have not only an insulating layer but also wiring on the insulating layer. Examples of the wiring include wiring derived from the metal foil provided on the metal-clad laminates and the like.

[0006] In recent years, the difference between printed wiring boards (PCBs) and semiconductor package substrates (PKGs), as exemplified by substrate-like PCBs, has been narrowing. Furthermore, electronic devices, particularly small portable devices such as mobile communication terminals and notebook PCs, have rapidly become more multifunctional, more powerful, thinner, and smaller, and information communication speeds have also increased significantly. Accordingly, there is a growing demand for finer conductor wiring, more multi-layered conductor wiring layers, thinner designs, and higher performance in terms of mechanical properties, for the substrates, such as PCBs and PKGs, that are used in these products.

[0007] Wiring boards and the like used in various electronic devices are also required to be resistant to the effects of reflow and other processes during mounting. For example, to ensure that wiring boards can be used without problems even after reflow processing, substrate materials for forming the insulating layers of wiring boards are required to produce cured products with excellent heat resistance, such as a high glass transition temperature. Furthermore, it is also required that the insulating layers provided on wiring boards do not deform due to the effects of reflow and other processes. Since a high glass transition temperature of the insulating layer suppresses this deformation, substrate materials for forming the insulating layers of wiring boards are required to produce cured products with excellent heat resistance, such as a high glass transition temperature. Furthermore, as wiring boards become thinner, semiconductor packages equipped with semiconductor chips on wiring boards tend to warp, which can lead to mounting defects. To suppress warping of semiconductor packages equipped with semiconductor chips on wiring boards, the insulating layer is required to have a low thermal expansion coefficient. Therefore, substrate materials for forming the insulating layers of wiring boards are required to produce cured products with a low thermal expansion coefficient. Furthermore, to suppress losses due to increased resistance associated with miniaturized wiring, the insulating layers provided on wiring boards are increasingly required to have low dielectric properties. For these reasons, substrate materials for wiring boards and the like are required to have lower dielectric properties than the resin composition described in Patent Document 1 in order to accommodate high frequencies, and are also required to have both excellent heat resistance and a low coefficient of thermal expansion. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2017 / 209108 Summary of the Invention

[0009] The present invention has been made in view of the above circumstances, and aims to provide a resin composition that can give a cured product having low dielectric properties, excellent heat resistance, and a low coefficient of thermal expansion. 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.

[0010] One aspect of the present invention is a resin composition containing: maleimide compound (A) having a maleimide equivalent weight of 500 g / eq. or less and being solid at 25°C, wherein the maleimide compound is soluble in a mixture of the maleimide compound and at least one selected from the group consisting of toluene and methyl ethyl ketone at 25°C at a concentration within a range of 40% by mass or more and less than 100% by mass; and polymerizable compound (B) having a carbon-carbon unsaturated double bond in the molecule and having a ratio of the total mass of heteroatoms to the total mass of all constituent elements of 15% by mass or less. [Brief explanation of the drawings]

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

[0012] As a result of extensive investigations, the present inventors have found that the above object can be achieved by the present invention described below.

[0013] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these.

[0014] [Resin composition] The resin composition according to the present embodiment contains: (A) a maleimide compound having a maleimide equivalent weight of 500 g / eq. or less and being solid at 25° C., the maleimide compound being soluble in a mixture of the maleimide compound and at least one selected from the group consisting of toluene and methyl ethyl ketone at a concentration ranging from 40% by mass to less than 100% by mass at 25° C.; and (B) a polymerizable compound having a carbon-carbon unsaturated double bond in its molecule and having a ratio of the total mass of heteroatoms to the total mass of all constituent elements of 15% by mass or less. By curing a resin composition having such a configuration, a cured product having low dielectric properties, excellent heat resistance, and a low coefficient of thermal expansion can be obtained.

[0015] The maleimide compound (A) has a maleimide equivalent of 500 g / eq. or less and is solid at 25°C. Therefore, by curing the polymerizable compound (B) together with the maleimide compound (A) in the resin composition, it is believed that the high glass transition temperature of the maleimide compound (A) can be maintained and heat resistance can be improved. Furthermore, by curing the polymerizable compound (B) together with the maleimide compound (A), it is believed that a cured product with excellent low dielectric properties can be obtained. The maleimide compound (A) dissolves in a mixture of the maleimide compound (A) and at least one selected from the group consisting of toluene and methyl ethyl ketone at 25°C at a concentration of 40% by mass or more and less than 100% by mass. Therefore, for example, the resin composition can be easily dissolved in these solvents to form a varnish. When the varnish is formed, the maleimide compound (A) and the polymerizable compound (B) are suitably dispersed, resulting in a suitable cured product. Furthermore, by containing the maleimide compound (A) and the polymerizable compound (B), the resin composition is believed to be able to suppress sedimentation of the inorganic filler even when the resin composition contains an inorganic filler. Since the resin composition can be cured favorably, it is believed that the heat resistance and thermal expansion coefficient of the resulting cured product can be reduced. For these reasons, it is believed that the resin composition can provide a cured product with excellent low dielectric properties and heat resistance and a low thermal expansion coefficient.

[0016] (Maleimide compound (A)) The maleimide compound (A) is not particularly limited as long as it has a maleimide equivalent of 500 g / eq. or less and is solid at 25°C, and the concentration of the maleimide compound in a mixture of the maleimide compound and at least one selected from the group consisting of toluene and methyl ethyl ketone at 25°C is within the range of 40% by mass or more and less than 100% by mass.

[0017] The maleimide equivalent of the maleimide compound (A) is 500 g / eq. or less, preferably 150 to 500 g / eq., and more preferably 150 to 450 g / eq. If the maleimide equivalent is too high, the glass transition temperature of the resulting cured product tends to be low, and the heat resistance tends to be reduced. Therefore, since the maleimide compound (A) has a maleimide equivalent within the above range and is solid at 25°C, by curing the polymerizable compound (B) together with the maleimide compound (A) in the resin composition, the high glass transition temperature of the maleimide compound (A) can be maintained and the heat resistance can be improved.

[0018] The maleimide compound (A) dissolves at a concentration within a range of 40% by mass or more and less than 100% by mass in a mixture of the maleimide compound (A) and at least one solvent selected from the group consisting of toluene and methyl ethyl ketone at 25° C. That is, when the maleimide compound (A) dissolves in the mixture obtained by mixing the maleimide compound (A) with the solvent at 25° C., the concentration of the maleimide compound (A) in the mixture is 40% by mass or more and less than 100% by mass.

[0019] The mixing is not particularly limited as long as the mixing conditions are such that dissolution is possible (for example, the concentration is such that the maleimide compound (A) can be dissolved), and examples thereof include stirring. The mixing conditions are also not particularly limited, and in the case of stirring, the stirring time may be, for example, 10 to 120 minutes. The solvent constituting the mixture may be toluene alone, methyl ethyl ketone alone, or a mixed solvent of toluene and methyl ethyl ketone. Here, dissolution refers to a state in which the solvent and the maleimide compound (A) are mixed to form a uniform liquid phase (solution), and examples thereof include a state in which no precipitates or suspended matter are visually observed in the finally obtained mixture, and the mixture is visually recognized as transparent. Furthermore, when the synthesis of the maleimide compound (A) is carried out in the solvent and the solution after the production of the maleimide compound (A) has a concentration within the above range, even after leaving the solution at 25°C for a long period of time, for example, one week, if no precipitate or suspended matter is visually confirmed in the liquid obtained after the reaction and the liquid remains visually transparent, this state is also considered to be a solution (a state in which the maleimide compound (A) is dissolved in the solvent).

[0020] As described above, the concentration (the concentration of the maleimide compound (A) soluble in the mixture at 25°C) is 40% by mass or more and less than 100% by mass, and preferably 50% by mass or more and less than 100% by mass. If the maleimide compound has a too low concentration, the resin composition tends to be difficult to form into a varnish, making it difficult to obtain a suitable cured product. Therefore, if the maleimide compound has a concentration within the above range, for example, the resin composition can be easily dissolved in these solvents to form a varnish, and when formed into a varnish, the maleimide compound (A) and the polymerizable compound (B) are suitably dispersed, resulting in a suitable cured product. Since the resin composition can be suitably cured, the heat resistance and thermal expansion coefficient of the resulting cured product can be reduced.

[0021] Examples of the maleimide compound (A) include a maleimide compound (A1) having an arylene structure oriented at the meta position in the molecule, and a maleimide compound (A2) having an indane structure in the molecule. Either one of these maleimide compounds may be used, or these two may be used in combination.

[0022] The maleimide compound (A1) having an arylene structure bonded in a meta-oriented manner in the molecule is not particularly limited as long as it is a maleimide compound having an arylene structure bonded in a meta-oriented manner in the molecule. Examples of the arylene structure bonded in a meta-oriented manner include an arylene structure in which a structure containing a maleimide group is bonded in the meta-position (an arylene structure in which a structure containing a maleimide group is substituted at the meta-position). The arylene structure bonded in a meta-oriented manner is an arylene group bonded in a meta-oriented manner, such as a group represented by the following formula (9). Examples of the arylene structure bonded in a meta-oriented manner include m-arylene groups such as m-phenylene and m-naphthylene, and more specifically, a group represented by the following formula (9).

[0023] [ka]

[0024] Examples of the maleimide compound (A1) having an arylene structure in the molecule oriented and bonded at the meta position include a maleimide compound (A3) represented by the following formula (3), and more specifically, a maleimide compound (A4) represented by the following formula (4).

[0025] [ka] In formula (3), Ar2 represents an arylene group bonded in a meta-position. A , R B , R C , and R Dare 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.

[0026] 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 specifically, examples thereof include groups represented by the formula (9).

[0027] 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.

[0028] 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.

[0029] In the maleimide compound (A3) 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).

[0030] [ka] In formula (4), 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).

[0031] The maleimide compound (A3) represented by the formula (3) and the maleimide compound (A4) represented by the formula (4) may contain a monofunctional compound where s is 0, or a polyfunctional compound such as a heptafunctional compound or an octafunctional compound where s is 6 or more, as long as s, which is the average value of the repeating number (degree of polymerization), is 1 to 5.

[0032] As the maleimide compound (A1) having an arylene structure in the molecule oriented and bonded at the meta position, a commercially available product may be used, and for example, the solid content in MIR-5000-60T manufactured by Nippon Kayaku Co., Ltd. may be used.

[0033] As the maleimide compound (A1) having an arylene structure oriented at the meta position in the molecule, the maleimide compounds exemplified above may be used alone or in combination of two or more. For example, as the maleimide compound, the maleimide compound (A3) represented by formula (3) may be used alone, or two or more types of the maleimide compound (A3) represented by formula (3) may be used in combination. When two or more types of the maleimide compound (A3) represented by formula (3) are used in combination, for example, a maleimide compound (A3) represented by formula (3) other than the maleimide compound (A4) represented by formula (4) may be used in combination with the maleimide compound (A4) represented by formula (4).

[0034] The maleimide compound (A2) having an indane structure in its molecule is not particularly limited as long as it is a maleimide compound having an indane structure in its molecule. Examples of the indane structure include a divalent group formed by removing two hydrogen atoms from indane or indane substituted with a substituent, and more specifically, a structure represented by the following formula (5). The maleimide compound (A2) having an indane structure in its molecule also has a maleimide group in its molecule. Examples of the maleimide compound having an indane structure in its molecule include a maleimide compound having a structure represented by the following formula (5) in its molecule, and more specifically, a maleimide compound (A5) having a structure represented by the following formula (6) in its molecule.

[0035] [ka] In formula (5), 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 bonded to the same benzene ring may be the same group or different groups. Rb represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group (alkoxy group) having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group (thiol group). r represents an integer of 0 to 3.

[0036] [ka] In formula (6), 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 (5), 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.

[0037] r is the average value of the substitution degree 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. A maleimide compound (A2) having the indane structure of such r in the molecule 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, the cycloalkyl group having 3 to 6 carbon atoms, and the 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.

[0038] Specific examples of the groups represented by Ra and Rb include the following groups.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] The aryl group having 6 to 10 carbon atoms is not particularly limited, and examples thereof include a phenyl group and a naphthyl group.

[0043] The aryloxy group having 6 to 10 carbon atoms is not particularly limited, and examples thereof include a phenyloxy group and a naphthyloxy group.

[0044] The arylthio group having 6 to 10 carbon atoms is not particularly limited, and examples thereof include a phenylthio group and a naphthylthio group.

[0045] 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.

[0046] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0047] 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 the indane structure of such q in the molecule 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.

[0048] 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 represented by formula (5) and the maleimide compound (A5) represented by formula (6), the content of the maleimide compound having an indane structure in the molecule, 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) having an indane structure in the molecule.

[0049] The maleimide compound (A2) having an indane structure in the molecule preferably has a molecular weight distribution (Mw / Mn) measured by 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).

[0050] The maleimide compound (A2) having an indane structure in the molecule preferably further has an arylene structure in the molecule that is bonded in a meta-oriented manner. Examples of the arylene structure bonded in a meta-oriented manner include an arylene structure in which a structure containing a maleimide group (i.e., other than Rb) is bonded in the meta-position (an arylene structure in which a structure containing a maleimide group is substituted at the meta-position). The arylene structure bonded in a meta-oriented manner is an arylene group bonded in a meta-oriented manner, such as the group represented by formula (9). Examples of the arylene structure bonded in a meta-oriented manner include m-arylene groups such as m-phenylene and m-naphthylene groups, and more specifically, examples of the group represented by formula (9).

[0051] Specific examples of the maleimide compound (A2) having an indane structure in the molecule include maleimide compounds represented by formulas (10) to (12). These maleimide compounds (A2) further have an arylene group in the molecule that is oriented and bonded at the meta position, such as the group represented by formula (9).

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

[0053] [ka] In the formula (11), n ​​represents 0.95 to 10.

[0054] [ka] In the formula (12), n represents 0.95 to 10.

[0055] The method for producing the maleimide compound (A2) having an indane structure in the molecule is not particularly limited, as long as it can produce the maleimide compound (A2) having an indane structure in the molecule. Specifically, the maleimide compound having an indane structure in the molecule can be obtained by a so-called maleimidation reaction in which an amine compound represented by the following formula (13) is reacted with maleic anhydride in an organic solvent such as toluene in the presence of a catalyst such as toluenesulfonic acid. More specifically, after the maleimidation reaction, unreacted maleic anhydride and other impurities are removed by washing with water or the like, and the solvent is removed under reduced pressure. A dehydrating agent may be used during this reaction. Commercially available products may also be used as the maleimide compound (A2) having an indane structure in the molecule.

[0056] [ka] In formula (13), 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 (1), 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.

[0057] The amine compound represented by the formula (13) can be obtained, for example, by reacting 2,6-dimethylaniline with α,α'-dihydroxy-1,3-diisopropylbenzene in an organic solvent such as xylene using activated clay as a catalyst.

[0058] (Polymerizable compound (B)) The polymerizable compound (B) is not particularly limited as long as it has a carbon-carbon unsaturated double bond in the molecule and the ratio of the total mass of heteroatoms to the total mass of all constituent elements is 15 mass% or less.

[0059] The polymerizable compound (B) has a carbon-carbon unsaturated double bond in its molecule. Examples of the carbon-carbon unsaturated double bond include double bonds contained in unsaturated hydrocarbon groups such as vinyl, allyl, and isopropenyl, but do not include double bonds contained in maleimide groups. Furthermore, the polymerizable compound (B) has a total mass ratio of heteroatoms to the total mass of all constituent elements of 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 0% by mass. The lower the total mass ratio of heteroatoms to the total mass of all constituent elements in the polymerizable compound (B), the better, and it is preferred that the polymerizable compound (B) does not contain heteroatoms. The heteroatom is an atom other than carbon or hydrogen, and examples thereof include nitrogen, oxygen, sulfur, phosphorus, chlorine, iodine, and bromine atoms. That is, the total mass of carbon atoms and hydrogen atoms in the polymerizable compound (B) relative to the total mass of all constituent elements is 85% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 100% by mass. If the heteroatoms are too numerous, the resulting resin composition tends to have poor low dielectric properties, such as a high dielectric loss tangent, in its cured form. Therefore, by using a polymerizable compound having a carbon-carbon unsaturated double bond in its molecule and in which the ratio of the total mass of heteroatoms to the total mass of all constituent elements is 15% by mass or less, a resin composition can be obtained that forms a cured product with excellent low dielectric properties.

[0060] Examples of the polymerizable compound (B) include a polyphenylene ether compound (B1) having a carbon-carbon unsaturated double bond in the molecule, and a hydrocarbon compound (B2) having a carbon-carbon unsaturated double bond in the molecule. Either one of these compounds may be used as the polymerizable compound (B), or these two compounds may be used in combination.

[0061] The polyphenylene ether compound (B1) 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 (B1) include polyphenylene ether compounds having a carbon-carbon unsaturated double bond at the molecular end, and more specifically, polyphenylene ether compounds having a substituent having a carbon-carbon unsaturated double bond at the molecular end, such as modified polyphenylene ether compounds whose ends are modified with a substituent having a carbon-carbon unsaturated double bond.

[0062] Examples of the substituent having a carbon-carbon unsaturated double bond include a group represented by the following formula (14) and a group represented by the following formula (15). That is, examples of the polyphenylene ether compound (B1) include a polyphenylene ether compound having at least one selected from the group represented by the following formula (14) and the group represented by the following formula (15) at a molecular end.

[0063] [ka] In formula (14), R7 to R9 are independent of each other. That is, R7 to R9 may be the same group or different groups. R7 to R9 represent a hydrogen atom or an alkyl group. Ar3 represents an arylene group. p represents 0 to 10. In addition, when p is 0 in formula (14), it means that Ar3 is directly bonded to the end of the polyphenylene ether.

[0064] The arylene group is not particularly limited. Examples of the arylene group include monocyclic aromatic groups such as a phenylene group and polycyclic aromatic groups such as a naphthalene ring. The arylene group also includes derivatives in which a hydrogen atom bonded to the aromatic ring is substituted with a functional group such as an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0065] The alkyl group is not particularly limited, and is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0066] [ka] In formula (15), R 10 represents a hydrogen atom or an alkyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0067] Examples of the group represented by the formula (14) include a vinylbenzyl group (ethenylbenzyl group) represented by the following formula (16): Furthermore, examples of the group represented by the formula (15) include an acryloyl group and a methacryloyl group.

[0068] [ka]

[0069] More specifically, examples of the substituent include vinylbenzyl groups (ethenylbenzyl groups) such as o-ethenylbenzyl, m-ethenylbenzyl, and p-ethenylbenzyl groups, vinylphenyl groups, acryloyl groups, and methacryloyl groups. The polyphenylene ether compound (B1) may have one type of substituent, or two or more types. The polyphenylene ether compound (B1) may have, for example, any one of o-ethenylbenzyl, m-ethenylbenzyl, and p-ethenylbenzyl groups, or two or three types thereof.

[0070] The polyphenylene ether compound (B1) has a polyphenylene ether chain in the molecule, and preferably has, for example, a repeating unit represented by the following formula (17) in the molecule.

[0071] [ka] In formula (17), t represents 1 to 50. 11 ~R 14 are independent of each other. That is, R 11 ~R 14 may be the same group or different groups. 11 ~R 14 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0072] R 11 ~R 14 Specific examples of the functional groups mentioned in the above include the following:

[0073] The alkyl group is not particularly limited, but is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0074] The alkenyl group is not particularly limited, but is preferably an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples include a vinyl group, an allyl group, and a 3-butenyl group.

[0075] The alkynyl group is not particularly limited, but is preferably an alkynyl group having 2 to 18 carbon atoms, and more preferably an alkynyl group having 2 to 10 carbon atoms. Specific examples include an ethynyl group and a prop-2-yn-1-yl group (propargyl group).

[0076] The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, but for example, an alkylcarbonyl group having 2 to 18 carbon atoms is preferred, and an alkylcarbonyl group having 2 to 10 carbon atoms is more preferred. Specific examples include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pivaloyl group, a hexanoyl group, an octanoyl group, and a cyclohexylcarbonyl group.

[0077] The alkenylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkenyl group, but for example, an alkenylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkenylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include an acryloyl group, a methacryloyl group, and a crotonoyl group.

[0078] The alkynylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkynyl group, but for example, an alkynylcarbonyl group having 3 to 18 carbon atoms is preferable, and an alkynylcarbonyl group having 3 to 10 carbon atoms is more preferable. Specific examples include a propioloyl group.

[0079] The weight-average molecular weight (Mw) of the polyphenylene ether compound (B1) is not particularly limited. Specifically, it is preferably 500 to 5,000, more preferably 800 to 4,000, and even more preferably 1,000 to 3,000. The weight-average molecular weight may be measured by a general molecular weight measurement method, specifically, a value measured using gel permeation chromatography (GPC), etc. Furthermore, when the polyphenylene ether compound (B1) has a repeating unit represented by the above formula (17) in the molecule, t is preferably a numerical value such that the weight-average molecular weight of the polyphenylene ether compound (B1) falls within this range. Specifically, t is preferably 1 to 50.

[0080] When the weight-average molecular weight of the polyphenylene ether compound (B1) is within this range, the compound has the excellent low dielectric properties of polyphenylene ether, and the cured product not only has excellent heat resistance but also has excellent moldability. This is believed to be due to the following reasons. When the weight-average molecular weight of a typical polyphenylene ether is within this range, the compound has a relatively low molecular weight, which tends to reduce the heat resistance of the cured product. In contrast, the polyphenylene ether compound (B1) according to this embodiment has one or more unsaturated double bonds at its terminals, which is believed to result in a cured product with sufficiently high heat resistance. Furthermore, when the weight-average molecular weight of the polyphenylene ether compound is within this range, the compound has a relatively low molecular weight, which is believed to result in excellent moldability. Therefore, it is believed that such a polyphenylene ether compound not only provides a cured product with excellent heat resistance but also excellent moldability.

[0081] The average number of the substituents (number of terminal functional groups) at the molecular terminals per molecule of the polyphenylene ether compound (B1) is not particularly limited. Specifically, it is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.5 to 3. If the number of terminal functional groups is too small, it tends to be difficult to obtain a cured product with sufficient heat resistance. On the other hand, if the number of terminal functional groups is too large, the reactivity becomes too high, which may cause problems such as reduced shelf life and reduced fluidity of the resin composition. That is, when such a polyphenylene ether compound is used, insufficient fluidity may cause molding defects such as the generation of voids during multilayer molding, which may lead to moldability problems such as difficulty in obtaining a highly reliable printed wiring board.

[0082] The number of terminal functional groups in a polyphenylene ether compound may be, for example, a numerical value representing the average number of the substituents per molecule of all polyphenylene ether compounds present in 1 mole of the polyphenylene ether compound. The number of terminal functional groups can be measured, for example, by measuring the number of hydroxyl groups remaining in the resulting polyphenylene ether compound and calculating the difference from the number of hydroxyl groups in the polyphenylene ether before the substituents are introduced (before modification). This difference from the number of hydroxyl groups in the polyphenylene ether before modification is the number of terminal functional groups. The number of hydroxyl groups remaining in the polyphenylene ether compound can be measured by adding a quaternary ammonium salt (tetraethylammonium hydroxide) that associates with hydroxyl groups to a solution of the polyphenylene ether compound and measuring the UV absorbance of the resulting mixed solution.

[0083] The intrinsic viscosity of the polyphenylene ether compound (B1) is not particularly limited. Specifically, it may be 0.03 to 0.12 dL / g, preferably 0.04 to 0.11 dL / g, and more preferably 0.06 to 0.095 dL / g. If the intrinsic viscosity is too low, the molecular weight tends to be low, and it tends to be difficult to achieve low dielectric properties such as a low relative dielectric constant and a low dielectric loss tangent. On the other hand, if the intrinsic viscosity is too high, the viscosity tends to be high, sufficient fluidity cannot be achieved, and the moldability of the cured product tends to be reduced. Therefore, if the intrinsic viscosity of the polyphenylene ether compound is within the above range, excellent heat resistance and moldability of the cured product can be achieved.

[0084] The intrinsic viscosity here is the intrinsic viscosity measured in methylene chloride at 25°C, and more specifically, for example, is the value measured using a viscometer for a 0.18 g / 45 ml methylene chloride solution (liquid temperature: 25°C). Examples of such a viscometer include the AVS500 Visco System manufactured by Schott.

[0085] Examples of the polyphenylene ether compound (B1) include a polyphenylene ether compound represented by the following formula (7) and a polyphenylene ether compound represented by the following formula (8). As the polyphenylene ether compound (B1), these polyphenylene ether compounds may be used alone or in combination.

[0086] [ka]

[0087] [ka]

[0088] In formula (18) and formula (19), R 15 ~R 22 and R 23 ~R 30 are independent of each other. That is, R 15 ~R 22 and R 23 ~R 30 may be the same group or different groups. 15 ~R 22 and R 23 ~R 30 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. X1 and X2 are each independent. That is, X1 and X2 may be the same group or different groups. X1 and X2 represent a substituent having a carbon-carbon unsaturated double bond. B1 and B2 represent repeating units represented by the following formula (20) and formula (21), respectively. In addition, in formula (19), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms.

[0089] [ka]

[0090] [ka]

[0091] In the formulas (20) and (21), m1 and m2 each represent an integer of 0 to 20. 31 ~R 34 and R 35 ~R 38 are independent of each other. That is, R 31 ~R 34 and R 35 ~R 38 may be the same group or different groups. 31 ~R 34 and R 35 ~R 38 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0092] The polyphenylene ether compound represented by the formula (18) and the polyphenylene ether compound represented by the formula (19) are not particularly limited as long as they satisfy the above-mentioned constitution. Specifically, in the formulas (18) and (19), R 15 ~R 22 and R 23 ~R 30 are independent of each other, as mentioned above. That is, R 15 ~R 22 and R 23 ~R 30 may be the same group or different groups. 15 ~R 22 and R 23 ~R 30 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0093] In formula (20) and formula (21), m1 and m2 each preferably represent a value of 0 to 20, as described above. Furthermore, m1 and m2 preferably represent a value such that the sum of m1 and m2 is 1 to 30. Therefore, it is more preferable that m1 represents a value of 0 to 20, m2 represents a value of 0 to 20, and the sum of m1 and m2 represents a value of 1 to 30. Furthermore, R 31 ~R 34 and R 35 ~R 38 are independent of each other. That is, R 31 ~R 34 and R 35 ~R 38 may be the same group or different groups. 31 ~R 34 and R 35 ~R 38 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0094] R 15 ~R 38 is R in the above formula (17) 11 ~R 14 is the same as

[0095] In the formula (19), Y is, as described above, a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms. Examples of Y include a group represented by the following formula (22).

[0096] [ka] In the formula (22), R 39 and R 40 are each independently a hydrogen atom or an alkyl group. Examples of the alkyl group include a methyl group. Examples of the group represented by formula (22) include a methylene group, a methylmethylene group, and a dimethylmethylene group, and among these, a dimethylmethylene group is preferred.

[0097] In the formula (18) and the formula (19), X1 and X2 each independently represent a substituent having a carbon-carbon double bond. In the polyphenylene ether compound represented by the formula (18) and the polyphenylene ether compound represented by the formula (19), X1 and X2 may be the same group or different groups.

[0098] More specific examples of the polyphenylene ether compound represented by the formula (18) include polyphenylene ether compounds represented by the following formula (23).

[0099] [ka]

[0100] More specific examples of the polyphenylene ether compound represented by the formula (19) include a polyphenylene ether compound represented by the following formula (24) and a polyphenylene ether compound represented by the following formula (25).

[0101] [ka]

[0102] [ka]

[0103] In the above formulas (23) to (25), m1 and m2 are the same as m1 and m2 in the above formulas (20) and (21). In addition, in the above formulas (23) and (24), R7 to R9, p, and Ar3 are the same as R7 to R9, p, and Ar3 in the above formula (25). In addition, in the above formulas (24) and (25), Y is the same as Y in the above formula (19). In addition, in the above formula (25), R 10 is R in the above formula (15). 10 is the same as

[0104] The method for synthesizing the polyphenylene ether compound (B1) used in this embodiment is not particularly limited as long as it can synthesize a polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule. Specific examples of this method include a method of reacting a polyphenylene ether with a compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded.

[0105] Examples of the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded include compounds in which a halogen atom is bonded to a substituent represented by the formulas (14) to (16). Specific examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom, with a chlorine atom being preferred. More specific examples of the compound in which a halogen atom is bonded to a substituent having a carbon-carbon unsaturated double bond include o-chloromethylstyrene, p-chloromethylstyrene, and m-chloromethylstyrene. The compound in which a halogen atom is bonded to a substituent having a carbon-carbon unsaturated double bond may be used alone or in combination of two or more. For example, o-chloromethylstyrene, p-chloromethylstyrene, and m-chloromethylstyrene may be used alone or in combination of two or more.

[0106] The polyphenylene ether used as the raw material is not particularly limited as long as it can ultimately synthesize a predetermined polyphenylene ether compound (B1). Specific examples include polyphenylene ethers composed of 2,6-dimethylphenol and at least one of a bifunctional phenol and a trifunctional phenol, and compounds containing polyphenylene ether as the main component, such as poly(2,6-dimethyl-1,4-phenylene oxide). A bifunctional phenol is a phenolic compound having two phenolic hydroxyl groups per molecule, such as tetramethylbisphenol A. A trifunctional phenol is a phenolic compound having three phenolic hydroxyl groups per molecule.

[0107] The polyphenylene ether compound (B1) can be synthesized by the method described above. Specifically, the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded are dissolved in a solvent and stirred. By doing so, the polyphenylene ether reacts with the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, thereby obtaining the polyphenylene ether compound (B1) used in this embodiment.

[0108] The reaction is preferably carried out in the presence of an alkali metal hydroxide. It is believed that this allows the reaction to proceed smoothly. This is believed to be because the alkali metal hydroxide functions as a dehydrohalogenating agent, specifically, a dehydrochlorinating agent. That is, it is believed that the alkali metal hydroxide eliminates hydrogen halide from the phenol group of the polyphenylene ether and the compound in which the substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and as a result, the substituent having a carbon-carbon unsaturated double bond is bonded to the oxygen atom of the phenol group in place of the hydrogen atom of the phenol group of the polyphenylene ether.

[0109] The alkali metal hydroxide is not particularly limited as long as it can act as a dehalogenating agent, and examples thereof include sodium hydroxide, etc. The alkali metal hydroxide is usually used in the form of an aqueous solution, specifically, an aqueous sodium hydroxide solution.

[0110] The reaction conditions, such as reaction time and reaction temperature, vary depending on the compound in which the substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom, and are not particularly limited as long as the reaction proceeds favorably. Specifically, the reaction temperature is preferably room temperature to 100°C, more preferably 30 to 100°C. The reaction time is preferably 0.5 to 20 hours, more preferably 0.5 to 10 hours.

[0111] The solvent used in the reaction is not particularly limited as long as it can dissolve the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and does not inhibit the reaction between the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded. Specific examples include toluene.

[0112] The above reaction is preferably carried out in the presence of not only an alkali metal hydroxide but also a phase transfer catalyst. That is, the above reaction is preferably carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst. Doing so is believed to allow the reaction to proceed more smoothly. This is believed to be due to the following: A phase transfer catalyst has the function of incorporating an alkali metal hydroxide, is soluble in both a polar solvent phase such as water and a nonpolar solvent phase such as an organic solvent, and is capable of transferring between these phases. Specifically, when an aqueous solution of sodium hydroxide is used as the alkali metal hydroxide and an organic solvent such as toluene, which is incompatible with water, is used as the solvent, even if the aqueous solution of sodium hydroxide is added dropwise to the solvent being used for the reaction, the solvent and the aqueous solution of sodium hydroxide separate, and it is believed that the sodium hydroxide is unlikely to migrate to the solvent. In this case, it is believed that the aqueous solution of sodium hydroxide added as the alkali metal hydroxide is unlikely to contribute to promoting the reaction. On the other hand, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst, the alkali metal hydroxide is transferred to the solvent while being incorporated into the phase transfer catalyst, and the aqueous sodium hydroxide solution is thought to contribute more to promoting the reaction. Therefore, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst, the reaction is thought to proceed more smoothly.

[0113] The phase transfer catalyst is not particularly limited, but examples thereof include quaternary ammonium salts such as tetra-n-butylammonium bromide.

[0114] The resin composition used in this embodiment preferably contains the polyphenylene ether compound obtained as described above as the polyphenylene ether compound (B1).

[0115] The hydrocarbon compound (B2) is not particularly limited as long as it is a hydrocarbon compound having a carbon-carbon unsaturated double bond in the molecule. The hydrocarbon compound (B2) also includes hydrocarbon resins having a carbon-carbon unsaturated double bond in the molecule and polymers of the hydrocarbon compounds. Examples of the hydrocarbon compound (B2) include compounds represented by the following formula (1), compounds represented by the following formula (26), polyfunctional vinyl aromatic polymers, cyclic polyolefin resins, and vinyl aromatic compound-conjugated diene compound copolymers.

[0116] As described above, examples of the hydrocarbon compound (B2) include the compounds represented by the following formula (1).

[0117] [ka] In formula (1), R1 to R3 each independently represent a hydrogen atom or an alkyl group. A represents a hydrogen atom, an alkyl group, an alkenyl group, or a group represented by the following formula (2). a represents an integer from 1 to 1000. When a is 2 or more, the hydrocarbon compound (B2) preferably contains at least one structural unit represented by formula (1), and may contain two or more different structural units in combination.

[0118] The alkyl group in the formula (1) is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0119] The alkenyl group in the formula (1) is not particularly limited, but is preferably an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples include a vinyl group, an allyl group, and a 3-butenyl group.

[0120] In the compound represented by formula (1), the repeating unit a is preferably 1 to 1000, more preferably 2 to 500. This a is the average value of the repeating number (degree of polymerization). Furthermore, the hydrocarbon compound (B2) may contain a repeating unit of the structural unit represented by formula (1). In this case, when a is 2 or more, the hydrocarbon compound (B2) preferably contains at least one repeating unit of the structural unit represented by formula (1), and may contain a combination of two or more different repeating units.

[0121] [ka] In formula (2), R4 to R6 each independently represent a hydrogen atom or an alkyl group, Ar1 represents an arylene group, and b represents 0 or 1.

[0122] The alkyl group is not particularly limited, and is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0123] The alkenyl group is not particularly limited, but is preferably an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples include a vinyl group, an allyl group, and a 3-butenyl group.

[0124] More specifically, the group represented by formula (2) includes the following formulas (7) and (8): The compound represented by formula (1) preferably includes a compound containing, in the molecule, either a group represented by formula (7) or a group represented by formula (8) as the group represented by formula (2).

[0125] [ka] In formula (7), R4 represents a hydrogen atom or an alkyl group.

[0126] [ka]

[0127] As described above, examples of the hydrocarbon compound (B2) include the compound represented by the following formula (26).

[0128] [ka] In formula (26), x represents 1 to 20. In the compound represented by formula (26), x is preferably 1 to 12, and more preferably 1 to 6. Specific examples of the compound represented by formula (26) include a compound represented by formula (26) where x is 1 [bis(4-vinylphenyl)methane (BVPM)], a compound represented by formula (26) where x is 2 [1,2-bis(vinylphenyl)ethane (BVPE)], and a compound represented by formula (26) where x is 6 [1,6-bis(4-vinylphenyl)hexane (BVPH)].

[0129] As a method for producing the compound represented by the formula (26), for example, when producing a compound represented by the formula (26) in which x is 2, the compound can be produced by subjecting 1-(chloromethyl)-4-vinylbenzene to a Grignard reaction.

[0130] The polyfunctional vinyl aromatic polymer can be exemplified by a polymer obtained by polymerizing at least one of a polyfunctional vinyl aromatic compound and its derivative, that is, a polymer containing at least one of a structure derived from a polyfunctional vinyl aromatic compound and a structure derived from a derivative of the polyfunctional vinyl aromatic compound in its molecule.The polyfunctional vinyl aromatic polymer can be a polymer containing one of a structure derived from a polyfunctional vinyl aromatic compound and a structure derived from a derivative of the polyfunctional vinyl aromatic compound in its molecule, or a polymer containing two or more of them in its molecule.

[0131] The polyfunctional vinyl aromatic compound is a compound containing two or more vinyl groups and a single or condensed aromatic ring in the molecule. Among the polyfunctional vinyl aromatic compounds, the divinyl aromatic compound having two vinyl groups is not particularly limited, but for example, m-divinylbenzene, p-divinylbenzene, 1,2-diisopropenylbenzene, 1,3-diisopropenylbenzene, 1,4-diisopropenylbenzene, 1,3-divinylnaphthalene, 1,8-divinylnaphthalene, 1,4-divinylnaphthalene, 1,5-divinylnaphthalene, 2,3-divinylnaphthalene, 2,7-divinyl Examples thereof include naphthalene, 2,6-divinylnaphthalene, 4,4'-divinylbiphenyl, 4,3'-divinylbiphenyl, 4,2'-divinylbiphenyl, 3,2'-divinylbiphenyl, 3,3'-divinylbiphenyl, 2,2'-divinylbiphenyl, 2,4-divinylbiphenyl, 1,2-divinyl-3,4-dimethylbenzene, 1,3-divinyl-4,5,8-tributylnaphthalene, 2,2'-divinyl-4-ethyl-4'-propylbiphenyl, etc. These may be used alone or in combination of two or more.

[0132] Specific examples of suitable divinylaromatic compounds include divinylbenzene (both m- and p-isomers), divinylbiphenyl (including each isomer), and divinylnaphthalene (including each isomer), in terms of cost and the heat resistance of the resulting polymer. Specific examples of more preferred compounds include divinylbenzene (both m- and p-isomers) and divinylbiphenyl (including each isomer). Divinylbenzene (both m- and p-isomers) is particularly preferred. Furthermore, in fields requiring high heat resistance, divinylbiphenyl (including each isomer) and divinylnaphthalene (including each isomer) are preferably used.

[0133] The derivatives of the polyfunctional vinyl aromatic compounds include derivatives of these polyfunctional vinyl aromatic compounds. The polyfunctional vinyl aromatic polymer may also be a polymer obtained by further polymerizing a monovinyl aromatic compound or other compounds. That is, the polyfunctional vinyl aromatic polymer may be a polymer having not only a structure derived from a polyfunctional vinyl aromatic compound and a structure derived from a derivative of the polyfunctional vinyl aromatic compound, but also a structure derived from a monovinyl aromatic compound and a structure derived from other compounds in the molecule.

[0134] The monovinyl aromatic compound is a compound containing one vinyl group and a single or condensed aromatic ring in the molecule. Examples of the monovinyl aromatic compound include ethylvinyl aromatic compounds and monovinyl aromatic compounds other than the ethylvinyl aromatic compounds.

[0135] The ethyl vinyl aromatic compound is not particularly limited, and examples thereof include o-ethyl vinylbenzene, m-ethyl vinylbenzene, p-ethyl vinylbenzene, 2-vinyl-2'-ethylbiphenyl, 2-vinyl-3'-ethylbiphenyl, 2-vinyl-4'-ethylbiphenyl, 3-vinyl-2'-ethylbiphenyl, 3-vinyl-3'-ethylbiphenyl, 3-vinyl-4'-ethylbiphenyl, 4-vinyl-2'-ethylbiphenyl, 4-vinyl-3'-ethylbiphenyl, and 4-vinyl-4'-ethylbiphenyl. These may be used alone or in combination of two or more. Specific examples of suitable ethyl vinyl aromatic compounds include ethyl vinylbenzene (both m- and p-isomers) and ethyl vinyl biphenyl (including each isomer), in terms of cost, gelation prevention, and heat resistance of the resulting polymer.

[0136] Examples of monovinyl aromatic compounds other than the ethylvinyl aromatic compounds include aromatic compounds having one polymerizable double bond, in which the carbon atom constituting the vinyl group of the monovinyl aromatic compound may be substituted with an alkyl group or the like.

[0137] The monovinyl aromatic compound is not particularly limited, but examples thereof include unsubstituted monovinyl aromatic compounds such as styrene and vinylnaphthalene, nuclear alkyl-substituted aromatic vinyl compounds such as p-methylstyrene and other nuclear alkyl-substituted styrenes, α-alkyl-substituted styrenes such as α-methylstyrene, α-alkyl-substituted aromatic vinyl compounds, and alkoxy-substituted styrenes such as 4-t-butoxystyrene. Examples of the monovinyl aromatic compound also include cyclic olefins such as indenes and acenaphthylenes. These may be used alone or in combination of two or more.

[0138] Among these, the monovinyl aromatic compound is preferably styrene, α-alkyl-substituted styrene, or α-alkyl-substituted aromatic vinyl compound, since it produces a large amount of indane structure in the copolymer skeleton during polymerization. Specific examples of suitable monovinyl aromatic compounds include styrene, α-methylstyrene, and 4-t-butoxystyrene, from the viewpoints of cost and the heat resistance of the resulting polymer. The monovinyl aromatic compound is effective for improving the flatness and flowability of the cured product of the resin composition, or for improving compatibility with other resins.

[0139] The polyfunctional vinyl aromatic copolymer is obtained by polymerizing monomers including the divinylaromatic compound and the monovinyl aromatic compound. The amount of the divinylaromatic compound used is preferably 20 to 99 mol%, more preferably 30 to 95 mol%, and even more preferably 50 to 85 mol%, based on the total amount of the divinylaromatic compound and the monovinyl aromatic compound. If the content of structural units derived from the divinylaromatic compound is too low, when the resulting polyfunctional vinyl aromatic copolymer is cured, the curability and heat resistance tend to decrease.

[0140] The amount of the monovinyl aromatic compound used is preferably 1 to 80 mol %, more preferably 5 to 70 mol %, and even more preferably 15 to 50 mol %, based on the total amount of the divinyl aromatic compound used and the monovinyl aromatic compound used. If the content of the structural unit derived from the monovinyl aromatic compound is too high, the heat resistance of the resulting polyfunctional vinyl aromatic copolymer tends to decrease when cured.

[0141] The ratio of the ethyl vinyl aromatic compound to the monovinyl aromatic compound other than the ethyl vinyl aromatic compound is not particularly limited, and it is preferable to use them in a ratio that ensures good compatibility when blending other resin components with the resulting polyfunctional vinyl aromatic copolymer.

[0142] The monomers forming the polyfunctional vinyl aromatic copolymer may contain, in addition to the divinyl aromatic compound and the monovinyl aromatic compound, small amounts of other monomers such as trivinyl aromatic compounds, other divinyl compounds, and monovinyl compounds, as long as the effects of the present invention are not impaired. These may be used alone or in combination of two or more. The amount of the other monomers used is preferably less than 30 mol %, more preferably 0 to 15 mol %, based on the total amount of the monomers including the divinyl aromatic compound and the monovinyl aromatic compound.

[0143] Even when the other monomers are contained, it is preferable that the amount of the divinyl aromatic compound and the amount of the monovinyl aromatic compound used in the total amount of monomers satisfy the above-mentioned use amounts (mol %), and the same applies to the more preferred ranges and the even more preferred ranges.

[0144] Examples of the cyclic polyolefin resin include compounds having a chain containing an alicyclic compound in the main chain or side chain. Examples of the chain containing an alicyclic compound include chains containing structures represented by the following structural formulas (27) to (35).

[0145] [ka]

[0146] [ka]

[0147] [ka]

[0148] [ka]

[0149] [ka]

[0150] [ka]

[0151] [ka]

[0152] [ka]

[0153] [ka]

[0154] Examples of the cyclic polyolefin resin include a cycloolefin copolymer (COC) type in which norbornene and ethylene are copolymerized using a metallocene catalyst, and a cycloolefin polymer (COP) type that undergoes metathesis ring-opening polymerization. These cyclic polyolefin resins may be used alone or in combination of two or more. Examples of commercially available cyclic polyolefin resins include Zeonex (registered trademark) and Zeonor (registered trademark) manufactured by Zeon Corporation, Arton (registered trademark) manufactured by JSR Corporation, Apel (registered trademark) manufactured by Mitsui Chemicals, Inc., and Topas (registered trademark) manufactured by Polyplastics Co., Ltd.

[0155] The vinyl aromatic compound-conjugated diene compound copolymer is not particularly limited as long as it is a copolymer containing a structure derived from a vinyl aromatic compound and a structure derived from a conjugated diene compound in the molecule. The vinyl aromatic compound-conjugated diene compound copolymer is a copolymer obtained by polymerizing a monomer containing the vinyl aromatic compound and the conjugated diene compound. Examples of the vinyl aromatic compound-conjugated diene compound copolymer include copolymers obtained by polymerizing a monomer containing one or more vinyl aromatic compounds and one or more conjugated diene compounds. The vinyl aromatic compound-conjugated diene compound copolymer also includes at least a partially hydrogenated one.

[0156] The vinyl aromatic compound is a compound or derivative thereof having one or more vinyl groups and an aromatic ring in the molecule, such as styrene, styrene derivatives, compounds in which some of the hydrogen atoms of the aromatic ring are substituted with alkyl groups, compounds in which some of the hydrogen atoms of the vinyl group in styrene are substituted with alkyl groups, 2-vinylnaphthalene, divinylbenzene, vinyltoluene, α-methylstyrene, butylstyrene, dimethylstyrene, and isopropenyltoluene. Examples of compounds in which some of the hydrogen atoms of the aromatic ring are substituted with alkyl groups include α-methylstyrene and p-methylstyrene. The vinyl aromatic compound may be used alone or in combination of two or more.

[0157] The conjugated diene compound is a compound having a conjugated diene in the molecule, and examples thereof include 1,3-butadiene, isoprene, 1,3-pentadiene, 1,4-pentadiene, 1,3-heptadiene, cyclopentadiene, 2,3-dimethyl-1,3-butadiene, 1,4-hexadiene, 1,5-hexadiene, 1,3-cyclohexadiene, 1,4-cyclohexadiene, and polymers thereof. These conjugated diene compounds may be used alone or in combination of two or more.

[0158] The vinyl aromatic compound-conjugated diene compound copolymer may be a copolymer obtained by polymerizing a monomer containing the vinyl aromatic compound and the conjugated diene compound, and further containing a compound copolymerizable with at least one of the vinyl aromatic compound and the conjugated diene compound. Examples of the copolymerizable compound include olefins such as α-pinene, β-pinene, and dipentene, and non-conjugated dienes such as 1,4-hexadiene and 3-methyl-1,4-hexadiene. The copolymerizable compounds may be used alone or in combination of two or more.

[0159] Examples of the vinyl aromatic compound-conjugated diene compound copolymer include methylstyrene (ethylene / butylene) methylstyrene copolymer, methylstyrene (ethylene-ethylene / propylene) methylstyrene copolymer, styrene-isoprene copolymer, styrene-isoprene styrene copolymer, styrene (ethylene / butylene) styrene copolymer, styrene (ethylene-ethylene / propylene) styrene copolymer, styrene-butadiene styrene copolymer, styrene (butadiene / butylene) styrene copolymer, styrene-isobutylene styrene copolymer, and hydrogenated products thereof. Examples of the hydrogenated products include hydrogenated methylstyrene (ethylene / butylene) methylstyrene copolymer, hydrogenated methylstyrene (ethylene-ethylene / propylene) methylstyrene copolymer, hydrogenated styrene-isoprene copolymer, hydrogenated styrene-isoprene styrene copolymer, hydrogenated styrene (ethylene / butylene) styrene copolymer, and hydrogenated styrene (ethylene-ethylene / propylene) styrene copolymer.

[0160] As the vinyl aromatic compound-conjugated diene compound copolymer, the above-exemplified vinyl aromatic compound-conjugated diene compound copolymers may be used alone or in combination of two or more.

[0161] The vinyl aromatic compound-conjugated diene compound copolymer preferably has a content of structural units derived from the vinyl aromatic compound of 5 to 95 mass%, more preferably 10 to 80 mass%, and even more preferably 20 to 50 mass%.

[0162] The vinyl aromatic compound-conjugated diene compound copolymer preferably has a weight-average molecular weight of 1,000 to 300,000, more preferably 1,200 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 when heat-molded 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).

[0163] (Inorganic filler) The inorganic filler is not particularly limited as long as it can be used as an inorganic filler contained in a resin composition. Examples of the inorganic filler include metal oxides such as silica, alumina, titanium oxide, magnesium oxide, and mica, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, talc, aluminum borate, barium sulfate, aluminum nitride, boron nitride, barium titanate, magnesium carbonate such as anhydrous magnesium carbonate, and calcium carbonate. Among these, silica, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, aluminum oxide, boron nitride, and barium titanate are preferred, and silica is more preferred. The silica is not particularly limited, and examples include crushed silica, spherical silica, and silica particles.

[0164] The inorganic filler may be a surface-treated or untreated inorganic filler. Examples of the surface treatment include treatment with a silane coupling agent.

[0165] Examples of the silane coupling agent include silane coupling agents having at least one functional group selected from the group consisting of a vinyl group, a styryl group, a methacryloyl group, an acryloyl group, a phenylamino group, an isocyanurate group, a ureido group, a mercapto group, an isocyanate group, an epoxy group, and an acid anhydride group. That is, the silane coupling agent has at least one reactive functional group selected from the group consisting of a vinyl group, a styryl group, a methacryloyl group, an acryloyl group, a phenylamino group, an isocyanurate group, a ureido group, a mercapto group, an isocyanate group, an epoxy group, and an acid anhydride group, and further includes compounds having a hydrolyzable group such as a methoxy group or an ethoxy group.

[0166] 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.

[0167] 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 laser diffraction or the like.

[0168] (hardening agent) The resin composition according to the present embodiment may contain, as necessary, a curing agent that reacts with at least one of the maleimide compound (A) and the polymerizable compound (B), provided that the effects of the present invention are not impaired. Here, the curing agent refers to a compound that reacts with at least one of the maleimide compound (A) and the polymerizable compound (B) to contribute to curing of the resin composition. Examples of the curing agent include a maleimide compound (C) other than the maleimide compound (A), an epoxy compound, a methacrylate compound, an acrylate compound, a cyanate ester compound, an active ester compound, a benzoxazine compound, and an allyl compound.

[0169] The maleimide compound (C) is a maleimide compound other than the maleimide compound (A) (a maleimide compound having a maleimide equivalent of 500 g / eq. or less, being solid at 25° C., and soluble in a mixture of the maleimide compound and at least one selected from the group consisting of toluene and methyl ethyl ketone at a concentration of 40% by mass or more and less than 100% by mass at 25° C.). Specifically, the maleimide compound (C) is a maleimide compound having a maleimide equivalent of more than 500 g / eq., a maleimide compound that is liquid at 25° C., or a maleimide compound that is insoluble in a mixture of the maleimide compound and at least one selected from the group consisting of toluene and methyl ethyl ketone at a concentration of 40% by mass or more and less than 100% by mass at 25° C. Examples of the maleimide compound (C) include maleimide compounds having a maleimide group in the molecule and not having an arylene structure or an indane structure bonded at the meta position in the molecule, such as maleimide compounds having one or more maleimide groups in the molecule, modified maleimide compounds, etc. Examples of the maleimide compound (C) include phenylmaleimide compounds such as 4,4'-diphenylmethane bismaleimide, polyphenylmethane 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, and 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, modified maleimide compounds in which a portion of the molecule is modified with a silicone compound, etc. Commercially available products may also be used as the maleimide compound (C), such as BMI-4000 and BMI-5100 manufactured by Daiwa Chemical Industry Co., Ltd., and BMI-689, BMI-1500, and BMI-3000J manufactured by Designer Molecules Inc.

[0170] 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, and naphthalene ring-containing epoxy compounds. The epoxy compound also includes epoxy resins, which are polymers of the above epoxy compounds.

[0171] 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).

[0172] 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.

[0173] 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.

[0174] 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.

[0175] The benzoxazine compound is a compound having a benzoxazine ring in the molecule, and examples thereof include benzoxazine resins.

[0176] 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).

[0177] The curing agent may be used alone or in combination of two or more kinds.

[0178] The weight-average molecular weight of the curing agent is not particularly limited, but is preferably 100 to 5000, more preferably 100 to 4000, and even more preferably 100 to 3000. If the weight-average molecular weight of the curing agent is too low, the curing agent may be more likely to volatilize from the resin composition's blending components. If the weight-average molecular weight of the curing agent is too high, the viscosity of the resin composition varnish or the melt viscosity during heat molding may be too high. Therefore, when the weight-average molecular weight of the curing agent is within this range, a resin composition with excellent heat resistance of the cured product can be obtained. This is thought to be because the resin composition can be cured appropriately. Note that the weight-average molecular weight may be measured using a general molecular weight measurement method, specifically, a value measured using gel permeation chromatography (GPC), etc.

[0179] The curing agent has an average number of functional groups per molecule that contribute to the reaction during curing of the resin composition (number of functional groups), which varies depending on the weight-average molecular weight of the curing agent, but is preferably, for example, 1 to 20, and more preferably 2 to 18. If the number of functional groups is too small, it tends to be difficult to obtain sufficient heat resistance of the cured product. On the other hand, if the number of functional groups is too large, the reactivity becomes too high, which may cause problems such as reduced storage stability and reduced fluidity of the resin composition.

[0180] (Content) The content of the maleimide compound (A) is preferably 10 to 90 parts by mass, and more preferably 15 to 80 parts by mass, relative to 100 parts by mass of the total mass of the maleimide compound (A) and the polymerizable compound (B). That is, the content of the polymerizable compound (B) is preferably 10 to 90 parts by mass, and more preferably 20 to 85 parts by mass, relative to 100 parts by mass of the total mass of the maleimide compound (A) and the polymerizable compound (B). Furthermore, when the resin composition contains the curing agent, the content of the curing agent is preferably 1 to 30 parts by mass, and more preferably 3 to 20 parts by mass, relative to 100 parts by mass of the total mass of the maleimide compound (A), the polymerizable compound (B), and the curing agent. If the content of the maleimide compound (A) is too low, the effects of adding the maleimide compound (A) are less likely to be achieved, and for example, the thermal expansion coefficient may not be sufficiently reduced, the glass transition temperature may be lowered, making it difficult to maintain excellent heat resistance, and adhesion to metal foil may tend to decrease. Furthermore, if the content of the maleimide compound (A) is too high, the water absorption of the cured product tends to increase. For these reasons, when the contents of the maleimide compound (A) and the polymerizable compound (B) are each within the above ranges, a cured product having excellent low dielectric properties and heat resistance, a low thermal expansion coefficient, and a low water absorption can be more suitably obtained.

[0181] As described above, the resin composition may contain an inorganic filler. When the resin composition contains the inorganic filler, the content of the inorganic filler is preferably 10 to 250 parts by mass, and more preferably 40 to 200 parts by mass, per 100 parts by mass of the total mass of the maleimide compound (A) and the polymerizable compound (B).

[0182] (Other ingredients) The resin composition according to the present embodiment may contain, as necessary, components other than the maleimide compound (A) and the polymerizable compound (B) (other components) within the scope of not impairing the effects of the present invention. The other components contained in the resin composition according to the present embodiment may include not only the curing agent and inorganic filler as described above, but also additives such as a reaction initiator, a reaction accelerator, a catalyst, a polymerization retarder, a polymerization inhibitor, a dispersant, a leveling agent, a silane coupling agent, an antifoaming agent, an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a dye or pigment, and a lubricant.

[0183] As described above, the resin composition according to this embodiment may contain a reaction initiator. The curing reaction can proceed even if the resin composition does not contain a reaction initiator. However, depending on the process conditions, it may be difficult to raise the temperature high enough for curing to proceed, so a reaction initiator may be added. 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 dicumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, and benzoyl peroxide. Examples of organic azo compounds include azobisisobutyronitrile. Furthermore, if necessary, a metal carboxylate or the like can be used in combination. This can further accelerate the curing reaction. Among these, α,α'-bis(t-butylperoxy-m-isopropyl)benzene is preferably used. Because α,α'-bis(t-butylperoxy-m-isopropyl)benzene has a relatively high reaction initiation temperature, it can suppress the acceleration of the curing reaction when curing is not necessary, such as during prepreg drying, and can suppress a decrease in the shelf life of the resin composition. Furthermore, because α,α'-bis(t-butylperoxy-m-isopropyl)benzene has low volatility, it does not volatilize during prepreg drying or storage, and therefore has good stability. Furthermore, the reaction initiators may be used alone or in combination of two or more.

[0184] 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.

[0185] As described above, the resin composition according to this embodiment may contain a flame retardant. The inclusion of a flame retardant can enhance the flame retardancy of the cured resin composition. The flame retardant is not particularly limited. Specifically, in fields where halogen-based flame retardants such as bromine-based flame retardants are used, preferred examples include ethylene dipentabromobenzene, ethylene bistetrabromoimide, decabromodiphenyl oxide, tetradecabromodiphenoxybenzene, and bromostyrene-based compounds that react with the polymerizable compounds, all of which have melting points of 300°C or higher. The use of a halogen-based flame retardant is believed to suppress halogen elimination at high temperatures and thus prevent a decrease in heat resistance. Furthermore, in fields requiring halogen-free materials, phosphorus-containing flame retardants (phosphorus-based flame retardants) are sometimes used. Examples of the phosphorus-based flame retardant include, but are not limited to, phosphate ester-based flame retardants, phosphazene-based flame retardants, bisdiphenylphosphine oxide-based flame retardants, and phosphinate-based flame retardants. A specific example of a phosphate ester-based flame retardant is a condensed phosphate ester of dixylenyl phosphate. A specific example of a phosphazene-based flame retardant is phenoxyphosphazene. A specific example of a bisdiphenylphosphine oxide-based flame retardant is xylylenebisdiphenylphosphine oxide. A specific example of a phosphinate-based flame retardant is, for example, a metal phosphinate salt of an aluminum dialkylphosphinate. As the flame retardant, each of the exemplified flame retardants may be used alone or in combination of two or more.

[0186] (Manufacturing method) The method for producing the resin composition is not particularly limited, and examples thereof include a method in which the maleimide compound (A) and the polymerizable compound (B) are mixed to a predetermined content, etc. In addition, in the case of obtaining a varnish-like composition containing an organic solvent, the method described below can be used.

[0187] Furthermore, 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.

[0188] [Prepreg] FIG. 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention.

[0189] 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.

[0190] 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 can be exemplified by the state between when the viscosity starts to increase and when the composition is completely cured.

[0191] 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 obtained by drying or heat-drying the resin composition.

[0192] 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 the base material for forming the prepreg. That is, the resin composition 2 is usually often a resin varnish prepared in a varnish form. Such a varnish-like resin composition (resin varnish) is prepared, for example, as follows.

[0193] First, each component that is soluble in an organic solvent is added to the organic solvent and dissolved. Heating may be performed if necessary. Subsequently, components that are insoluble in the organic solvent 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 polyphenylene ether compound (B1), the curing agent, and the like and does not inhibit the curing reaction. Specific examples include toluene and methyl ethyl ketone (MEK).

[0194] 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.

[0195] 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.

[0196] 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 possible to adjust the final composition and impregnation amount to the desired one.

[0197] 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. By heating, a prepreg 1 in an uncured (A-stage) or semi-cured (B-stage) state is obtained. The heating also volatilizes the organic solvent from the resin varnish, reducing or eliminating the organic solvent.

[0198] The resin composition according to the present embodiment is a resin composition that provides a cured product with excellent low dielectric properties and heat resistance and a low thermal expansion coefficient. Therefore, a prepreg including this resin composition or a semi-cured product of this resin composition is a prepreg that provides a cured product with excellent low dielectric properties and heat resistance and a low thermal expansion coefficient. This prepreg can be used to suitably manufacture wiring boards that include an insulating layer that includes a cured product with excellent low dielectric properties and heat resistance and a low thermal expansion coefficient.

[0199] [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.

[0200] 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 including 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 formed from a cured product of the resin composition or a cured product of the prepreg. The thickness of the metal foil 13 varies depending on the performance required of the final wiring board and is not particularly limited. The thickness of the metal foil 13 can be appropriately set depending on the desired purpose and is preferably, for example, 0.2 to 70 μm. Examples of the metal foil 13 include copper foil and aluminum foil. When the metal foil is thin, it may be a carrier-supported copper foil having a release layer and a carrier to improve handling.

[0201] 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 a method in which one or more prepregs 1 are stacked, and then a metal foil 13 such as copper foil is stacked on both or one of the upper and lower surfaces of the prepreg 1, and the metal foil 13 and the prepreg 1 are heated and pressurized to form an integrated laminate, thereby producing a double-sided or single-sided metal foil-clad laminate 11. That is, the metal-clad laminate 11 is obtained by stacking the metal foil 13 on the prepreg 1 and then heating and pressurizing the resulting laminate. The heating and pressurizing conditions can be appropriately set depending on the thickness of the metal-clad laminate 11, 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 4 MPa, and the time can be 60 to 150 minutes. The metal-clad laminate may also be produced without using a prepreg. For example, a method may be used in which a varnish-like resin composition is applied onto a metal foil to form a layer containing the resin composition on the metal foil, and then the layer is heated and pressed.

[0202] The resin composition according to the present embodiment is a resin composition that can yield a cured product with low dielectric properties, excellent heat resistance, and a low thermal expansion coefficient. Therefore, a metal-clad laminate having an insulating layer containing a cured product of this resin composition is a metal-clad laminate having an insulating layer containing a cured product with low dielectric properties, excellent heat resistance, and a low thermal expansion coefficient. This metal-clad laminate can then be used to suitably produce a wiring board having an insulating layer containing a cured product with low dielectric properties, excellent heat resistance, and a low thermal expansion coefficient.

[0203] [Wiring board] FIG. 3 is a schematic cross-sectional view showing an example of wiring board 21 according to an embodiment of the present invention.

[0204] 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 composed of 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.

[0205] The method for manufacturing the wiring board 21 is not particularly limited as long as it can produce the wiring board 21. Specifically, a method for manufacturing the wiring board 21 using the prepreg 1 can be used. Examples of such a method include a method for manufacturing the wiring board 21 by etching the metal foil 13 on the surface of the metal-clad laminate 11 manufactured as described above to form wiring, thereby manufacturing the wiring board 21 having wiring provided as a circuit on the surface of the insulating layer 12. That is, the wiring board 21 can be obtained by forming a circuit by partially removing the metal foil 13 on the surface of the metal-clad laminate 11. In addition to the above methods, other methods for forming a circuit include circuit formation by a semi-additive process (SAP) or a modified semi-additive process (MSAP). The wiring board 21 is a wiring board having an insulating layer 12 containing a cured product with low dielectric properties, excellent heat resistance, and a low thermal expansion coefficient.

[0206] [Metal foil with resin] FIG. 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil 31 according to this embodiment.

[0207] 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.

[0208] 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 obtained by drying or heat-drying the resin composition. The fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0209] 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.

[0210] 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 film, polyester film, polymethylpentene film, and films formed by providing a release agent layer on these films.

[0211] The method for producing the resin-coated metal foil 31 is not particularly limited as long as it can produce the resin-coated metal foil 31. Examples of methods for producing the resin-coated metal foil 31 include a method of applying the varnish-like resin composition (resin varnish) onto the metal foil 13 and heating it. The varnish-like resin composition is applied onto the metal foil 13, for example, using a bar coater. The applied resin composition is heated, for example, at a temperature of 40°C to 180°C for 0.1 minutes to 10 minutes. The heated resin composition is formed on the metal foil 13 as an uncured resin layer 32. Note that the heating volatilizes the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0212] The resin composition according to this embodiment is a resin composition that provides a cured product with excellent low dielectric properties and heat resistance and a low thermal expansion coefficient. Therefore, a resin-coated metal foil having a resin layer containing this resin composition or a semi-cured product of this resin composition is a resin-coated metal foil with a resin layer that provides a cured product with excellent low dielectric properties and heat resistance and a low thermal expansion coefficient. This resin-coated metal foil can be used to manufacture a wiring board that has an insulating layer that includes a cured product with excellent low dielectric properties and heat resistance and a low thermal expansion coefficient. For example, by laminating the resin-coated metal foil on a wiring board, a multilayer wiring board can be manufactured. A wiring board obtained using such a resin-coated metal foil includes an insulating layer that includes a cured product with excellent low dielectric properties and heat resistance and a low thermal expansion coefficient.

[0213] [Resin-coated film] FIG. 5 is a schematic cross-sectional view showing an example of a resin-coated film 41 according to the present embodiment.

[0214] 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.

[0215] The resin layer 42 may contain a semi-cured product of the resin composition as described above, or may contain the uncured resin composition. That is, the resin-coated film 41 may include a resin layer containing a semi-cured product of the resin composition (the resin composition in B stage) and a support film, or may be a resin-coated film including a resin layer containing the resin composition before curing (the resin composition in A stage) and a support film. The resin layer may contain the resin composition or a semi-cured product of the resin composition, and may or may not contain a fibrous substrate. The resin composition or the semi-cured product of the resin composition may be obtained by drying or heat-drying the resin composition. The fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0216] 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.

[0217] The resin-coated film 41 may be provided with a cover film or the like as needed. By providing a cover film, it is possible to prevent the inclusion of foreign matter, etc. The cover film is not particularly limited, but examples thereof include a polyolefin film, a polyester film, and a polymethylpentene film.

[0218] 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.

[0219] The method for producing the resin-coated film 41 is not particularly limited as long as it can produce the resin-coated film 41. Examples of methods for producing the resin-coated film 41 include a method in which the varnish-like resin composition (resin varnish) is applied to a support film 43 and heated. The varnish-like resin composition is applied to the support film 43 using, for example, a bar coater. The applied resin composition is heated, for example, at a temperature of 40°C to 180°C for 0.1 minutes to 10 minutes. The heated resin composition is formed on the support film 43 as an uncured resin layer 42. The heating volatilizes the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0220] The resin composition according to this embodiment is a resin composition that provides a cured product with excellent low dielectric properties and heat resistance and a low thermal expansion coefficient. Therefore, a resin-attached film having a resin layer containing this resin composition or a semi-cured product of this resin composition provides a cured product with excellent low dielectric properties and heat resistance and a low thermal expansion coefficient. This resin-attached film can be suitably used to manufacture a wiring board having an insulating layer containing a cured product with excellent low dielectric properties and heat resistance and a low thermal expansion coefficient. For example, a multilayer wiring board can be manufactured by laminating the resin-attached film on a wiring board and then peeling off the support film, or by laminating the resin-attached film on a wiring board after peeling off the support film. A wiring board obtained using such a resin-attached film includes an insulating layer containing a cured product with excellent low dielectric properties and heat resistance and a low thermal expansion coefficient.

[0221] According to the present invention, there is provided a resin composition that can provide a cured product having low dielectric properties, excellent heat resistance, and a low coefficient of thermal expansion. The present invention also provides a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board, which are obtained using the resin composition.

[0222] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples. [Example]

[0223] [Examples 1 to 17 and Comparative Examples 1 to 5] In this example, each component used in preparing the resin composition will be described.

[0224] (Maleimide compound (A)) Maleimide compound (A)-1: biphenylaralkyl-type maleimide compound (MIR-3000 manufactured by Nippon Kayaku Co., Ltd., maleimide equivalent: 275 g / eq., solid at 25°C)

[0225] When a mixed solvent of toluene and methyl ethyl ketone (MEK) in a mass ratio of 1:3 was used as the solvent, the maleimide compound (A)-1 was added to the solvent so that the solute concentration (the ratio of the maleimide compound (A)-1 to the total mass of the solvent and the maleimide compound (A)-1) was 40 mass%, and the mixture was then stirred at 25° C. for 60 minutes, resulting in a mixture in which the maleimide compound (A)-1 was dissolved. This indicates that the maleimide compound (A)-1 was a maleimide compound that was soluble in a mixture of the maleimide compound and at least one member selected from the group consisting of toluene and methyl ethyl ketone at 25° C. at a concentration ranging from 40 mass% to less than 100 mass%.

[0226] In this example, if no precipitate or suspended matter was visible in the resulting mixture and it was visually recognized as transparent, it was determined to be dissolved. If this was not the case (for example, if a precipitate was visible in the mixture, if suspended matter was visible in the mixture, and if it was not visually recognized as transparent), it was determined not to be dissolved (insoluble).

[0227] Maleimide compound (A)-2: a maleimide compound having an arylene structure in the molecule oriented at the meta position (solid content in MIR-5000-60T (maleimide compound dissolved in toluene) manufactured by Nippon Kayaku Co., Ltd., a maleimide compound represented by the formula (4), maleimide equivalent: 260 g / eq., solid at 25°C)

[0228] The maleimide compound (A)-2 was a mixture that had been left at 25°C for one week or more in a state where the solute concentration (the ratio of the maleimide compound (A)-2 to the total mass of the solvent and the maleimide compound (A)-2) was 60% by mass when toluene was used as a solvent. Since no precipitate or suspended matter was visually observed in this mixture and the mixture was visually recognized as transparent, it was determined that the maleimide compound (A)-2 was dissolved in toluene. Based on this, the maleimide compound (A)-2 was a maleimide compound that was soluble in a mixture of the maleimide compound and at least one member selected from the group consisting of toluene and methyl ethyl ketone at 25°C at a concentration of the maleimide compound ranging from 40% by mass to less than 100% by mass.

[0229] Maleimide compound (A)-3: A maleimide compound represented by the formula (6) (a maleimide compound having an indane structure in the molecule).

[0230] Specifically, it is a maleimide compound synthesized as follows.

[0231] 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. The temperature was then raised to 210 °C while removing the distillate water using a Dean-Stark tube. This reaction was carried out for 3 hours. The mixture was then cooled to 140 °C, and 145.4 g (1.2 mol) of 2,6-dimethylaniline was added, followed by heating to 220 °C. This reaction was carried out 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. The solvent and low-molecular-weight substances such as unreacted materials were distilled off under reduced pressure, yielding 364.1 g of solid. The obtained solid was an amine compound represented by the following formula (36) (amine equivalent: 298, softening point: 70° C.).

[0232] [ka]

[0233] Next, 131.8 g (1.3 mol) of maleic anhydride and 700 g of toluene were placed in a 2 L flask equipped with a thermometer, a condenser, a Dean-Stark tube, and a stirrer and stirred at room temperature. A mixed solution of 364.1 g of the amine compound represented by formula (36) and 175 g of DMF was then added dropwise over 1 hour. After the addition was completed, the mixture was stirred at room temperature for an additional 2 hours. 37.1 g of p-toluenesulfonic acid monohydrate was then added, and the reaction mixture was heated under reflux. The resulting azeotropic water and toluene were cooled and separated, and the toluene was then returned to the system for a dehydration reaction of 8 hours. After air-cooling to room temperature, the mixture was concentrated under reduced pressure. The brown solution was dissolved in 600 g of ethyl acetate, washed three times with 150 g of ion-exchanged water and three times with 150 g of 2% aqueous sodium bicarbonate solution, dried over sodium sulfate, and then concentrated under reduced pressure. The resulting reaction mixture was dried in vacuum at 80 °C for 4 hours to obtain 413.0 g of a solid. The obtained solid was analyzed by FD-MS spectroscopy, GPC, etc., and was found to be a maleimide compound represented by formula (6) (n was 1.47, and the molecular weight distribution (Mw / Mn) was 1.81). The maleimide equivalent of the obtained maleimide compound represented by formula (6) was 378 g / eq., and it was a solid at 25°C.

[0234] The maleimide compound (A)-3 was added to methyl ethyl ketone (MEK) as a solvent so that the solute concentration (ratio of the maleimide compound (A)-3 to the total mass of the solvent and the maleimide compound (A)-3) was 40% by mass, and the mixture was then stirred at 25° C. for 60 minutes, yielding a mixture in which the maleimide compound (A)-3 was dissolved. This indicates that the maleimide compound (A)-3 was a maleimide compound that was soluble in a mixture of the maleimide compound and at least one member selected from the group consisting of toluene and methyl ethyl ketone at 25° C. at a concentration ranging from 40% by mass to less than 100% by mass.

[0235] Maleimide compound (A)-4: A maleimide compound represented by the formula (6) (a maleimide compound having an indane structure in the molecule).

[0236] Specifically, it is a maleimide compound synthesized as follows.

[0237] 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. The temperature was then raised to 210 °C while removing the distillate water using a Dean-Stark tube. This reaction was carried out for 6 hours. The mixture was then cooled to 140 °C, and 145.4 g (1.2 mol) of 2,6-dimethylaniline was added, followed by heating to 220 °C. This reaction was carried out 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. The solvent and low-molecular-weight substances such as unreacted materials were distilled off under reduced pressure, yielding 345.2 g of solid. The obtained solid was the amine compound represented by the formula (36) (amine equivalent: 348, softening point: 71° C.).

[0238] Next, 131.8 g (1.3 mol) of maleic anhydride and 700 g of toluene were placed in a 2 L flask equipped with a thermometer, a condenser, a Dean-Stark tube, and a stirrer and stirred at room temperature. A mixed solution of 345.2 g of the amine compound represented by formula (36) and 175 g of DMF was then added dropwise over 1 hour. After the addition was completed, the mixture was stirred at room temperature for an additional 2 hours. 37.1 g of p-toluenesulfonic acid monohydrate was then added, and the reaction mixture was heated under reflux. The resulting azeotropic water and toluene were cooled and separated, and the toluene was then returned to the system for a dehydration reaction of 8 hours. After cooling to room temperature, the mixture was concentrated under reduced pressure. The brown solution was dissolved in 600 g of ethyl acetate, washed three times with 150 g of ion-exchanged water and three times with 150 g of 2% aqueous sodium bicarbonate solution, dried over sodium sulfate, and then concentrated under reduced pressure. The resulting reaction mixture was dried in vacuum at 80 °C for 4 hours to obtain 407.6 g of a solid. The obtained solid was analyzed by FD-MS spectroscopy, GPC, etc., and was found to be a maleimide compound represented by formula (6) (n was 2.59, and the molecular weight distribution (Mw / Mn) was 1.49). The maleimide equivalent of the obtained maleimide compound represented by formula (6) was 428 g / eq., and it was a solid at 25°C.

[0239] The maleimide compound (A)-4 was added to toluene as a solvent so that the solute concentration (ratio of the maleimide compound (A)-4 to the total mass of the solvent and the maleimide compound (A)-4) was 60 mass%, and the mixture was then stirred at 25° C. for 60 minutes, yielding a mixture in which the maleimide compound (A)-4 was dissolved. This indicates that the maleimide compound (A)-4 was a maleimide compound that was soluble in a mixture of the maleimide compound and at least one selected from the group consisting of toluene and methyl ethyl ketone at 25° C. at a concentration ranging from 40 mass% to less than 100 mass%.

[0240] (Polymerizable compound (B)) Polymerizable compound (B)-1: A polymerizable compound having a carbon-carbon unsaturated double bond in the molecule, and in which the ratio of the total mass of heteroatoms to the total mass of all constituent elements is 0% by mass.

[0241] Specifically, it is a polymerizable compound obtained by the following reaction.

[0242] A 3000 ml flask was charged with 1.90 mol (271 ml) of divinylbenzene, 0.10 mol (14.0 ml) of ethylvinylbenzene, 2.00 mol (229 ml) of styrene, 2.70 mol (311 ml) of benzyl chloride, 0.135 mol (32.8 ml) of tetrahydrofuran, and 925 ml of toluene. The mixture was heated to 30°C, and then 42.1 ml of a toluene solution (2.14 mmol / ml) of 90 mmol of SnCl was added and stirred for 3 hours. This allowed the polymerization reaction to proceed in the flask. The polymerization reaction was then terminated by adding a small amount of methanol to the flask. The resulting reaction mixture was then allowed to cool to room temperature, and a large amount of methanol was added to the reaction mixture to precipitate the polymer. The resulting polymer was washed with methanol, filtered, and dried. The final polymer (copolymer) yield was 262.2 g, representing a yield of 56.5% by mass.

[0243] The weight average molecular weight Mw of the obtained copolymer was 7280, the number average molecular weight Mn was 2970, and the Mw / Mn ratio was 2.5. 1 H-NMR analysis and 13 C-NMR analysis revealed that the copolymer contained 47 mol% of structural units derived from divinylbenzene and ethylvinylbenzene, 53 mol% of structural units derived from styrene, and no heteroatoms.

[0244] Polymerizable compound (B)-2: 1,2-bis(vinylphenyl)ethane (BVPE) (a compound represented by the formula (26) where x is 2, a polymerizable compound having a carbon-carbon unsaturated double bond in the molecule and having a ratio of the total mass of heteroatoms to the total mass of all constituent elements of 0 mass %). Specifically, this is BVPE produced by subjecting vinylbenzyl chloride such as 1-(chloromethyl)-4-vinylbenzene to a Grignard reaction.

[0245] Specifically, the polymerizable compound (B)-2 was produced as follows.

[0246] First, 5.36 g (220 mmol) of granular magnesium for Grignard reaction (manufactured by Kanto Chemical Co., Ltd.) was placed in a 500 ml three-neck flask, and a dropping funnel, a nitrogen inlet tube, and a septum cap were attached.

[0247] The three-necked flask was heated and dehydrated in a dryer while stirring the granular magnesium with a stirrer under a nitrogen stream. Then, 300 ml of dry tetrahydrofuran was taken in a syringe and injected into the three-necked flask through the septum cap.

[0248] After cooling the solution in the three-neck flask to -5°C, 30.5 g (200 mmol) of vinylbenzyl chloride (Tokyo Chemical Industry Co., Ltd.) was added dropwise to the solution over approximately 4 hours using a dropping funnel. After the addition was completed, stirring was continued at 0°C for 20 hours to allow the vinylbenzyl chloride reaction to proceed. After the reaction was completed, the solution obtained by the reaction was filtered to remove residual magnesium and concentrated using an evaporator. This concentrated solution was diluted with hexane, washed once with 3.6% aqueous hydrochloric acid and three times with pure water, and then dehydrated with magnesium sulfate. This dehydrated solution was purified by passing through a short column of silica gel (Wakogel C300, Fujifilm Wako Pure Chemical Industries, Ltd.) / hexane and dried in vacuum to obtain BVPE.

[0249] Polymerizable compound (B)-3: divinylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd., a polymerizable compound having a carbon-carbon unsaturated double bond in the molecule and having a ratio of the total mass of heteroatoms to the total mass of all constituent elements of 0% by mass) Polymerizable compound (B)-4: A polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) at the end (a modified polyphenylene ether compound obtained by reacting polyphenylene ether with chloromethylstyrene).

[0250] Specifically, it is a modified polyphenylene ether compound obtained by the following reaction.

[0251] First, 200 g of polyphenylene ether (SA90 manufactured by SABIC Innovative Plastics, 2 terminal hydroxyl groups, weight-average molecular weight Mw 1700), 30 g of a 50:50 mass ratio mixture of p-chloromethylstyrene and m-chloromethylstyrene (chloromethylstyrene: CMS manufactured by Tokyo Chemical Industry Co., Ltd.), 1.227 g of tetra-n-butylammonium bromide as a phase transfer catalyst, and 400 g of toluene were charged into a 1-liter three-neck flask equipped with a temperature controller, stirrer, cooling equipment, and dropping funnel, and the mixture was stirred. The mixture was then stirred until the polyphenylene ether, chloromethylstyrene, and tetra-n-butylammonium bromide were dissolved in the toluene. The mixture was gradually heated until the liquid temperature reached 75°C. An aqueous sodium hydroxide solution (20 g sodium hydroxide / 20 g water) was added dropwise to the solution as an alkali metal hydroxide over 20 minutes. The mixture was then stirred at 75°C for an additional 4 hours. Next, the contents of the flask were neutralized with 10% by mass of hydrochloric acid, and then a large amount of methanol was added. This caused a precipitate to form in the liquid in the flask. In other words, the product contained in the reaction solution in the flask was reprecipitated. This precipitate was then filtered, washed three times with a mixture of methanol and water in an 80:20 mass ratio, and then dried under reduced pressure at 80°C for 3 hours.

[0252] The obtained solid was 1The solid was analyzed by H-NMR (400 MHz, CDCl3, TMS). As a result of NMR measurement, a peak derived from a vinylbenzyl group (ethenylbenzyl group) was confirmed at 5 to 7 ppm. This confirmed that the obtained solid was a modified polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) as the substituent at the molecular end in the molecule. Specifically, it was confirmed to be an ethenylbenzylated polyphenylene ether. This obtained modified polyphenylene ether compound had a carbon-carbon unsaturated double bond in the molecule, and the ratio of the total mass of heteroatoms to the total mass of all constituent elements was 12 mass%.

[0253] The number of terminal functional groups of the modified polyphenylene ether was measured as follows.

[0254] First, the modified polyphenylene ether was accurately weighed. The weight at that time was designated X (mg). Then, this weighed modified polyphenylene ether was dissolved in 25 mL of methylene chloride, and 100 μL of a 10 mass% ethanol solution of tetraethylammonium hydroxide (TEAH) (TEAH:ethanol (volume ratio) = 15:85) was added to the solution, and the absorbance (Abs) at 318 nm was measured using a UV spectrophotometer (UV-1600, manufactured by Shimadzu Corporation). Then, from the measurement results, the number of terminal hydroxyl groups of the modified polyphenylene ether was calculated using the following formula.

[0255] Residual OH amount (μmol / g) = [(25×Abs) / (ε×OPL×X)]×10 6 where ε is the extinction coefficient, 4700 L / mol cm, and OPL is the cell path length, 1 cm.

[0256] The calculated residual OH amount (number of terminal hydroxyl groups) of the modified polyphenylene ether was almost zero, which indicated that the hydroxyl groups of the polyphenylene ether before modification were almost entirely modified. This indicated that the decrease in the number of terminal hydroxyl groups from the polyphenylene ether before modification was the number of terminal hydroxyl groups of the polyphenylene ether before modification. In other words, it was found that the number of terminal hydroxyl groups of the polyphenylene ether before modification was the number of terminal functional groups of the modified polyphenylene ether. In other words, the number of terminal functional groups was two.

[0257] The intrinsic viscosity (IV) of the modified polyphenylene ether was measured in methylene chloride at 25°C. Specifically, the intrinsic viscosity (IV) of the modified polyphenylene ether was measured using a viscometer (AVS500 Visco System manufactured by Schott) for a 0.18 g / 45 ml methylene chloride solution (liquid temperature 25°C) of the modified polyphenylene ether. As a result, the intrinsic viscosity (IV) of the modified polyphenylene ether was 0.086 dL / g.

[0258] The molecular weight distribution of the modified polyphenylene ether was measured using GPC. The weight average molecular weight (Mw) was calculated from the obtained molecular weight distribution. As a result, Mw was 1,900.

[0259] (hardening agent) Maleimide compound (C)-1: a maleimide compound insoluble in toluene, methyl ethyl ketone, and a mixed solvent of toluene and methyl ethyl ketone (BMI, manufactured by K.I. Chemical Co., Ltd., maleimide equivalent: 179 g / eq., solid at 25°C, maleimide compound that does not have an arylene structure or an indane structure bonded in a meta-position in the molecule).

[0260] The maleimide compound (C)-1 was added to a solvent so that the solute concentration (the ratio of the maleimide compound (C)-1 to the total mass of the solvent and the maleimide compound (C)-1) was less than 5 mass %, and the mixture was then stirred at 25°C for 120 minutes, but the maleimide compound (C)-1 did not dissolve. It did not dissolve when toluene, methyl ethyl ketone, or a mixed solvent of toluene and methyl ethyl ketone was used as the solvent. This indicates that the maleimide compound (C)-1 is not the maleimide compound (A) (a maleimide compound having a maleimide equivalent of 500 g / eq. or less, which is solid at 25°C, but which dissolves at a concentration of 40 mass % or more and less than 100 mass % in a mixture of the maleimide compound and at least one selected from the group consisting of toluene and methyl ethyl ketone at 25°C).

[0261] Maleimide compound (C)-2: a maleimide compound that is liquid at 25°C (BMI-689 manufactured by Designer Molecules Inc., maleimide equivalent: 344 g / eq., maleimide compound that does not have an arylene structure or an indane structure bonded in a meta-position in the molecule)

[0262] As described above, maleimide compound (C)-2 is a maleimide compound that is liquid at 25° C., but is not a maleimide compound that is solid at 25° C. That is, maleimide compound (C)-2 is not the maleimide compound (A) (a maleimide compound having a maleimide equivalent of 500 g / eq. or less and being solid at 25° C., wherein the maleimide compound dissolves in a mixture of the maleimide compound and at least one selected from the group consisting of toluene and methyl ethyl ketone at 25° C. at a concentration of 40% by mass or more and less than 100% by mass). Note that the solubility of maleimide compound (C)-2 in a solvent was 50% by mass when toluene was used.

[0263] Maleimide compound (C)-3: a maleimide compound having a maleimide equivalent of 1500 g / eq. (BMI-3000 manufactured by Designer Molecules Inc., solid at 25°C, maleimide compound having no arylene structure or indane structure oriented at the meta position in the molecule)

[0264] As described above, maleimide compound (C)-3 is a maleimide compound having a maleimide equivalent of more than 500 g / eq., but is not a maleimide compound having a maleimide equivalent of 500 g / eq. or less. That is, maleimide compound (C)-3 is not the maleimide compound (A) (a maleimide compound having a maleimide equivalent of 500 g / eq. or less and being solid at 25°C, the maleimide compound being soluble in a mixture of the maleimide compound and at least one selected from the group consisting of toluene and methyl ethyl ketone at 25°C at a concentration of 40% by mass or more and less than 100% by mass). The solubility of maleimide compound (C)-3 in a solvent was 50% by mass when toluene was used.

[0265] Allyl compound: triallyl isocyanurate (TAIC) (TAIC manufactured by Nippon Kasei Chemical Co., Ltd., ratio of total mass of heteroatoms to total mass of all constituent elements: 36% by mass)

[0266] TAIC is a compound that has a carbon-carbon unsaturated double bond in the molecule, but the ratio of the total mass of heteroatoms to the total mass of all constituent elements exceeds 15 mass %.

[0267] Methacrylate compound: tricyclodecane dimethanol dimethacrylate (DCP) (NK Ester DCP manufactured by Shin-Nakamura Chemical Co., Ltd., ratio of total mass of heteroatoms to total mass of all constituent elements: 19% by mass)

[0268] DCP is a compound that has a carbon-carbon unsaturated double bond in the molecule, but in which the ratio of the total mass of heteroatoms to the total mass of all constituent elements exceeds 15 mass %.

[0269] Epoxy compound: dicyclopentadiene epoxy resin (HP7200HHH manufactured by DIC Corporation) Benzoxazine compound: Pd-type benzoxazine compound (manufactured by Shikoku Chemicals Corporation) Cyanate ester compounds: Naphthol aralkyl cyanate ester compounds

[0270] Specifically, it is a cyanate ester compound obtained by the following reaction.

[0271] 300 g (1.28 mol in terms of OH groups) of 1-naphthol aralkyl resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) and 194.6 g (1.92 mol) of triethylamine (1.5 mol per 1 mol of hydroxy groups) were dissolved in 1800 g of dichloromethane to give solution 1.

[0272] 125.9 g (2.05 mol) of cyanogen chloride (1.6 mol per mol of hydroxyl groups), 293.8 g of dichloromethane, 194.5 g (1.92 mol) of 36% hydrochloric acid (1.5 mol per mol of hydroxyl groups), and 1205.9 g of water were mixed. While stirring the resulting mixture, the temperature was maintained at −2 to −0.5°C. Solution 1 was added over 30 minutes. After the addition of Solution 1, the mixture was stirred at the same temperature for 30 minutes, and then a solution (Solution 2) prepared by dissolving 65 g (0.64 mol) of triethylamine (0.5 mol per mol of hydroxyl groups) in 65 g of dichloromethane was added over 10 minutes. After the addition of Solution 2, the mixture was stirred at the same temperature for 30 minutes to complete the reaction.

[0273] The reaction mixture was then allowed to stand to separate into an organic phase and an aqueous phase. The resulting organic phase was washed five times with 1300 g of water. The electrical conductivity of the wastewater after the fifth wash was 5 μS / cm, confirming that the ionic compounds had been sufficiently removed by washing with water.

[0274] The organic phase after washing with water was concentrated under reduced pressure and finally concentrated to dryness at 90°C for 1 hour to obtain 331 g of the target naphthol aralkyl cyanate ester compound (SNCN) (orange viscous substance). The weight-average molecular weight Mw of the obtained SNCN was 600.

[0275] (Reaction initiator) Organic peroxide: Dicumyl peroxide (NOF Corporation) (Reaction accelerator) 2E4MZ: 2-ethyl-4-methylimidazole (2E4MZ manufactured by Shikoku Chemicals Corporation) Zinc octoate: Zinc octoate (Zn-Octoate 20%T manufactured by DIC Corporation) (Inorganic filler) Silica: Spherical silica (SO-C2 manufactured by Admatechs Co., Ltd.)

[0276] [Preparation method] First, each component other than the inorganic filler was added to toluene and mixed to a solids concentration of 50% by mass in the composition (parts by mass) shown in Tables 1 and 2. The mixture was stirred for 60 minutes. The filler was then added to the resulting liquid, and the inorganic filler was dispersed using a bead mill. This resulted in a varnish-like resin composition (varnish).

[0277] Next, a prepreg and an evaluation substrate (metal-clad laminate) were obtained as follows.

[0278] The obtained varnish was impregnated into a fibrous substrate (glass cloth: Asahi Kasei Corporation's GC2116L, #2116 type, L glass), and then heated and dried for 3 minutes at 110°C to produce a prepreg. At this time, the content of the components constituting the resin composition relative to the prepreg (resin content) was adjusted to approximately 57% by mass so that one prepreg would have a thickness of 125 μm due to the curing reaction.

[0279] Next, an evaluation substrate (metal-clad laminate) was obtained as follows.

[0280] Two or six of the obtained prepregs were stacked, and copper foil (FV-WS, 18 μm thick, manufactured by Furukawa Electric Co., Ltd.) was placed on both sides. This was used as a pressure body, and heated and pressed at a temperature of 220°C for 120 minutes under a pressure of 3 MPa to obtain evaluation substrates (metal-clad laminates) with copper foil adhered to both sides and a thickness of 250 μm (when two prepregs were stacked) or 750 μm (when six prepregs were stacked).

[0281] The prepregs and evaluation substrates (metal-clad laminates) prepared as described above were evaluated by the methods described below.

[0282] [Glass transition temperature (Tg)] An unclad plate, prepared by removing the copper foil by etching from the evaluation substrate (a metal-clad laminate with a thickness of 250 μm), was used as a test piece, and the Tg of the unclad plate was measured using a viscoelasticity spectrometer "DMS6100" manufactured by Seiko Instruments Inc. Dynamic viscoelasticity measurement (DMA) was performed using a tensile module at a frequency of 10 Hz, and the temperature at which tan δ reached a maximum when the temperature was raised from room temperature to 320°C at a heating rate of 5°C / min was taken as Tg (°C).

[0283] If the measured Tg exceeds 300° C., it is indicated in Tables 1 and 2 as “>300”.

[0284] [Dielectric properties (dissipation factor)] The dielectric loss tangent (DTA) of the unclad board, which was prepared by etching the copper foil off the 250 μm-thick metal-clad laminate, was measured at 10 GHz using a cavity resonator perturbation method. Specifically, the dielectric constant and DTA of the board were measured at 10 GHz using a network analyzer (Agilent Technologies N5230A).

[0285] [Thermal expansion coefficient] The copper foil was removed from the 750 μm thick metal-clad laminate by etching to prepare an unclad specimen. The coefficient of thermal expansion (CTEz: ppm / °C) of the cured resin composition in the Z-axis direction was measured using the TMA method (Thermo-mechanical analysis) in accordance with IPC-TM-650 2.4.24. The measurements were performed using a TMA device (TMA6000 manufactured by SII NanoTechnology Inc.) in the temperature range of 30 to 320°C.

[0286] The results of the above evaluations are shown in Tables 1 and 2. When the varnish could not be prepared, the evaluation is marked with "-".

[0287] [Table 1]

[0288] [Table 2]

[0289] As can be seen from Tables 1 and 2, in resin compositions containing a polymerizable compound having a carbon-carbon unsaturated double bond in the molecule and in which the ratio of the total mass of heteroatoms to the total mass of all constituent elements is 15 mass% or less, the resin compositions (Examples 1 to 17) containing a maleimide compound (maleimide compound (A)) having a maleimide equivalent of 500 g / eq. or less and being solid at 25°C, and in which the concentration of the maleimide compound in a mixture of at least one selected from the group consisting of toluene and methyl ethyl ketone and the maleimide compound at 25°C is within the range of 40 mass% or more and less than 100 mass%, resulted in cured products with higher glass transition temperatures, lower thermal expansion coefficients, and lower dielectric loss tangents, compared to cases in which no such maleimide compound was used. Specifically, the resin composition of Comparative Example 1, which was similar to Examples 1 to 4, failed to produce a varnish favorably, except that it contained a maleimide compound (the maleimide compound (C)-1) that had a maleimide equivalent of 500 g / eq. or less and was solid at 25°C, and was not one of the maleimide compounds (the maleimide compounds (A)-1 to (A)-4) that were soluble in a mixture of the maleimide compound and at least one member selected from the group consisting of toluene and methyl ethyl ketone at a concentration within a range of 40 mass% or more and less than 100 mass% at 25°C. Furthermore, even when using a maleimide compound (Comparative Examples 2 and 3) other than the maleimide compounds (A)-1 to (A)-4) that have a maleimide equivalent of 500 g / eq. or less and are solid at 25°C, and that dissolve at a concentration of 40% by mass or more and less than 100% by mass in a mixture of the maleimide compound and at least one selected from the group consisting of toluene and methyl ethyl ketone at 25°C, varnishes could be produced using the maleimide compounds (C)-2 and (C)-3). Compared with Comparative Example 2 and Comparative Example 3, the resin compositions of Examples 1 to 4 had higher glass transition temperatures and lower thermal expansion coefficients.Furthermore, the resin compositions according to Examples 1 to 4 did not contain a polymerizable compound having a carbon-carbon unsaturated double bond in the molecule and in which the ratio of the total mass of heteroatoms to the total mass of all constituent elements was 15% by mass or less, and instead contained a compound in which the total mass of heteroatoms exceeded 15% by mass, and had lower coefficients of thermal expansion than Comparative Examples 4 and 5, which were similar to Examples 1 to 4. Furthermore, Tables 1 and 2 show that cured products with high glass transition temperatures, low dielectric tangents, and low coefficients of thermal expansion were obtained regardless of whether the type of maleimide compound, the type of polymerizable compound, the content of the maleimide compound, or an additional curing agent was used.

[0290] The resin compositions according to Examples 1 to 17 and Comparative Examples 1 to 5 were also evaluated as follows.

[0291] [Water absorption rate] The copper foil was removed from the evaluation substrate (metal-clad laminate) by etching to obtain an unclad plate. The water absorption (%) of the test specimen was measured according to the method of IPC-TM-650 2.6.2.1. If the water absorption was less than 0.2%, it was evaluated as "◎", if it was 0.2% or more but less than 0.3%, it was evaluated as "○", and if it was 0.3% or more, it was evaluated as "×". Specifically, Examples 1 to 6, 9, 10, and 17 and Comparative Examples 2 and 3 were evaluated as "◎", Examples 11 and 13 to 16 were evaluated as "○", and Examples 7, 8, 12, and Comparative Examples 4 and 5 were evaluated as "×". From these results, it was found that when either Polymerizable Compound-1 or 2 was used as the polymerizable compound and its content was 15 parts by mass or more relative to 100 parts by mass of the total mass of the maleimide compound and the polymerizable compound, not only was the glass transition temperature high, the dielectric tangent low, and the thermal expansion coefficient low, but also the water absorption was low.

[0292] [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, a pattern 10 mm wide and 100 mm long was formed on the evaluation substrate, and the copper foil was peeled at a rate of 50 mm / min using a tensile tester, and the peel strength (N / mm) at this time was measured. As a result of the measurement, if the peel strength was 0.4 N / mm or more, it was evaluated as "◎", if it was 0.3 N / mm or more but less than 0.4 N / mm, it was evaluated as "◯", and if it was less than 0.3 N / mm, it was evaluated as "X". Specifically, Examples 8, 14, 15, and 17 and Comparative Examples 2 and 3 were evaluated as "◎", Examples 1 to 7, 12, 13, and 15 and Comparative Example 5 were evaluated as "◯", and Examples 9, 10, 17, and Comparative Example 4 were evaluated as "X". From this, when the content of the polymerizable compound is a certain amount or less, for example, 50 parts by mass or less, relative to 100 parts by mass of the total mass of the maleimide compound and the polymerizable compound, and when the content of the inorganic filler is a certain amount or less, for example, 150 parts by mass or less, not only do the glass transition temperature, the dielectric tangent, and the thermal expansion coefficient tend to be high, but also the peel strength tends to be high.

[0293] This application is based on Japanese Patent Application No. 2020-153181, filed on September 11, 2020, the contents of which are incorporated herein by reference.

[0294] 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. [Industrial Applicability]

[0295] The present invention provides a resin composition that can provide a cured product having low dielectric properties, excellent heat resistance, and a low coefficient of thermal expansion. 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 maleimide compound (A) having a maleimide equivalent of 500 g / eq. or less and being solid at 25°C, wherein the concentration of the maleimide compound in a mixture of the maleimide compound and at least one selected from the group consisting of toluene and methyl ethyl ketone at 25°C is in the range of 40% by mass or more and less than 100% by mass; a polymerizable compound (B) having a carbon-carbon unsaturated double bond in the molecule and having a ratio of the total mass of heteroatoms to the total mass of all constituent elements of 15 mass% or less; The maleimide compound (A) includes a maleimide compound (A2) having an indane structure in the molecule, the polymerizable compound (B) comprises either a polyphenylene ether compound (B1) having a carbon-carbon unsaturated double bond in the molecule or a hydrocarbon compound (B2) having a carbon-carbon unsaturated double bond in the molecule, The polyphenylene ether compound (B1) contains a polyphenylene ether compound represented by any one of the following formulas (23) to (25): The resin composition includes a compound in which the hydrocarbon compound (B2) includes a structural unit represented by the following formula (1): 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 [In formulas (23) to (25), m1 and m2 each represent an integer of 0 to 20; in formulas (23) and (24), R 7 to R 9 each independently represent a hydrogen atom or an alkyl group; p represents an integer of 0 to 10; Ar 3 represents an arylene group; in formulas (24) and (25), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms; and in formula (25), R 10 represents a hydrogen atom or an alkyl group.] 【Chemistry 4】 [In formula (1), R 1 to R 3 each independently represent a hydrogen atom or an alkyl group, A represents a hydrogen atom, an alkyl group, an alkenyl group, or a group represented by the following formula (2), and a represents an integer of 1 to 1,000.] 【Transformation 5】 [In formula (2), R 4 to R 6 each independently represent a hydrogen atom or an alkyl group, Ar 1 represents an arylene group, and b represents 0 or 1.]

2. The resin composition according to claim 1 , wherein the indane structure includes a structure represented by the following formula (5): 【Transformation 6】 [In formula (5), 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.]

3. The resin composition according to claim 2, wherein the maleimide compound having a structure represented by formula (5) in the molecule includes a maleimide compound (A5) represented by the following formula (6): 【Transformation 7】 [In formula (6), each Ra 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; 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 nitro group, a hydroxyl group, or a mercapto group; q represents 0 to 4; r represents 0 to 3; and n represents 0.95 to 10.]

4. The compound containing the structural unit represented by formula (1) contains a compound containing, as the group represented by formula (2), either a group represented by formula (7) or a group represented by formula (8) in the molecule. The resin composition according to any one of claims 1 to 3. 【Transformation 8】 [In formula (7), R ４ represents a hydrogen atom or an alkyl group. 【Chemistry 9】

5. The resin composition according to any one of claims 1 to 4, wherein the polymerizable compound (B) has a ratio of the total mass of heteroatoms to the total mass of all constituent elements of 10 mass% or less.

6. 6. The resin composition according to claim 1, wherein the content of the polymerizable compound (B) is 10 to 90 parts by mass relative to 100 parts by mass of the total mass of the maleimide compound (A) and the polymerizable compound (B).

7. The resin composition according to any one of claims 1 to 6, further comprising a curing agent that reacts with at least one of the maleimide compound (A) and the polymerizable compound (B).

8. The resin composition according to any one of claims 1 to 7, further comprising an inorganic filler.

9. The resin composition according to claim 8 , wherein the inorganic filler comprises silica.

10. 10. The resin composition according to claim 8, wherein the content of the inorganic filler is 10 to 250 parts by mass relative to 100 parts by mass of the total mass of the maleimide compound (A) and the polymerizable compound (B).

11. The resin composition according to any one of claims 1 to 10, further comprising a flame retardant.

12. A prepreg comprising the resin composition according to any one of claims 1 to 11 or a semi-cured product of the resin composition and a fibrous base material.

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

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

15. A metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 11 or a cured product of the prepreg according to claim 12, and a metal foil.

16. A wiring board comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 11 or a cured product of the prepreg according to claim 12, and wiring.

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