Resin composition, cured product, resin film, and resin composite sheet

Abstract

The present invention provides a resin composition, and a cured product, a resin film, and a resin composite sheet. A resin composition according to the present disclosure contains a thermoplastic elastomer and a thermosetting resin containing a maleimide compound. An elongation percentage at break of a dumbbell-shaped type 6 test piece having a thickness of 0.1 mm obtained by molding the thermoplastic elastomer under conditions of 200°C and 3 MPa, measured at a tensile speed of 5 mm / min in accordance with JIS K 6251, is 200% or more, and the elongation percentage at break after heating the test piece at 150°C for 3 hours is 200% or more. The resin composition does not contain a radical polymerization initiator.

Description

Resin compositions, cured products, resin films, and resin composite sheets

[0001] The present invention relates to resin compositions, cured products, resin films, and resin composite sheets.

[0002] In recent years, the integration and miniaturization of semiconductor elements used in mobile devices, electronic equipment, and communication devices has accelerated. Consequently, technologies that enable high-density mounting of semiconductor elements are required, and improvements are needed in printed circuit boards, such as substrates for mounting semiconductor elements, which play a crucial role in this process. Meanwhile, the applications of electronic devices are diversifying and expanding. As a result, the properties required of printed circuit boards, such as substrates for mounting semiconductor elements, and the resin films, resin composite sheets, prepregs, and metal foil laminates used therein, are also diversifying, and the required performance is becoming more stringent. Materials that meet these stringent requirements are described, for example, in Patent Document 1.

[0003] Japanese Patent Publication No. 2023-98886

[0004] In recent years, printed circuit boards have become thinner, and consequently, coreless substrates are in demand. To manufacture even thinner and finer wiring on coreless substrates, it is conceivable to use resin films or resin composite sheets that do not contain substrates such as glass cloth. When prepregs are used, the substrates such as glass cloth contained in the prepreg maintain toughness, but when resin films that do not contain substrates such as glass cloth are used, toughness tends to decrease. This decrease in toughness is causing problems with crack formation after thermal cycling tests (TCTs). The present invention aims to solve these problems and to provide a resin composition that can provide a cured product in which crack formation after thermal cycling tests is effectively suppressed, as well as a cured product, a resin film, and a resin composite sheet.

[0005] Based on the above problems, the inventors conducted studies and found that the above problems were solved by employing a resin composition containing a maleimide compound and a predetermined thermoplastic elastomer. Specifically, the above problems were solved by the following means: [1] A resin composition comprising a thermosetting resin containing a maleimide compound and a thermoplastic elastomer (A), wherein a dumbbell-shaped No. 6 test piece with a thickness of 0.1 mm, molded from thermoplastic elastomer (A) at 200°C and 3 MPa, has an elongation at break of 200% or more when measured at a tensile speed of 5 mm / min in accordance with JIS K 6251, and the elongation at break after heating the test piece at 150°C for 3 hours is 200% or more, and the resin composition does not contain a radical polymerization initiator. [2] The resin composition according to [1], wherein the content of thermoplastic elastomer (A) is 5 to 35 parts by mass per 100 parts by mass of resin solids contained in the resin composition. [3] The resin composition according to [1] or [2], wherein the thermoplastic elastomer (A) is a block copolymer having a styrene skeleton. [4] The resin composition according to any one of [1] to [3], wherein the proportion of units having a styrene skeleton in the thermoplastic elastomer (A) is 10 to 67% by mass. [5] The resin composition according to any one of [1] to [4], wherein the thermoplastic elastomer (A) is hydrogenated. [6] The resin composition according to any one of [1] to [5], wherein the thermoplastic elastomer (A) contains units having a styrene skeleton having a methyl group. [7] The resin composition according to any one of [1] to [6], wherein the thermoplastic elastomer (A) is a block copolymer having a styrene skeleton, the proportion of units having a styrene skeleton in the thermoplastic elastomer is 10 to 67% by mass, the thermoplastic elastomer (A) is hydrogenated, and the thermoplastic elastomer (A) contains units having a styrene skeleton having a methyl group. [8] The resin composition according to any one of [1] to [7], comprising a thermoplastic elastomer other than the thermoplastic elastomer (A), wherein the thermoplastic elastomer other than the thermoplastic elastomer (A) comprises a thermoplastic elastomer (A1) containing unhydrogenated conjugated diene compound units.[9] The resin composition according to any one of [1] to [8], further comprising a polyphenylene ether compound having a carbon-carbon unsaturated double bond at its terminus.

[10] The resin composition according to any one of [1] to [9], further comprising silica.

[11] The resin composition according to any one of [1] to

[10] , wherein 80% by mass or more of the thermosetting resin contained in the resin composition has a dielectric constant of 2.7 or less at a frequency of 10 GHz.

[12] The resin composition according to any one of [1] to

[11] , wherein the content of the thermoplastic elastomer (A) is 5 to 35 parts by mass per 100 parts by mass of resin solids contained in the resin composition, the thermoplastic elastomer (A) is a block copolymer having a styrene skeleton, the proportion of units having a styrene skeleton in the thermoplastic elastomer (A) is 10 to 67% by mass, the thermoplastic elastomer (A) is hydrogenated, the thermoplastic elastomer (A) contains units having a styrene skeleton having a methyl group, further contains a polyphenylene ether compound having a carbon-carbon unsaturated double bond at the terminal, further contains silica, and 80% by mass or more of the thermosetting resin contained in the resin composition has a dielectric constant of 2.7 or less at a frequency of 10 GHz.

[13] The resin composition according to

[12] , wherein the thermoplastic elastomer other than the thermoplastic elastomer (A) comprises a thermoplastic elastomer (A1) containing unhydrogenated conjugated diene compound units.

[14] A cured product of the resin composition according to any one of [1] to

[13] .

[15] A resin film formed from the resin composition according to any one of [1] to

[13] .

[16] The resin film according to

[15] , wherein the resin film does not contain glass cloth.

[17] A resin composite sheet having a support and a resin film formed from the resin composition according to any one of [1] to

[13] .

[18] The resin composite sheet according to

[17] , wherein the support is a metal foil or a thermoplastic resin film.

[19] The resin composite sheet according to

[17] , wherein the support is a copper foil or a polyethylene terephthalate film.

[20] The resin composite sheet according to

[17] , wherein the resin film does not contain glass cloth.

[0006] The present invention provides a resin composition capable of providing a cured product in which crack formation after temperature cycling tests is effectively suppressed, as well as a cured product, a resin film, and a resin composite sheet.

[0007] Hereinafter, embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment") will be described in detail. Note that the following embodiments are illustrative examples for explaining the present invention, and the present invention is not limited to these embodiments. In this specification, "~" is used to mean that the numerical values ​​before and after it include the lower and upper limits. "A~B" means A or greater and B or less. Furthermore, any combination of the upper and lower limits of numerical values ​​in this specification is given as an example of this embodiment. In this specification, various physical properties and characteristic values ​​are given at 23°C unless otherwise specified. In the notation of groups (atomic groups) in this specification, notations that do not specify substitution and unsubstituted include both groups (atomic groups) with substituents and groups (atomic groups) without substituents. For example, "alkyl group" includes not only alkyl groups without substituents (unsubstituted alkyl groups) but also alkyl groups with substituents (substituted alkyl groups). In this specification, when notations that do not specify substitution and unsubstituted are used, unsubstituted is preferred. Examples of substituents in this specification are preferably halogen atoms, cyano groups, nitro groups, hydroxyl groups, alkyl groups, alkoxy groups, aryl groups, aryloxy groups, heterocyclic groups, heterocyclic oxy groups, alkenyl groups, alkylsulfanyl groups, arylsulfanyl groups, acyl groups, or amino groups; more preferably halogen atoms, alkyl groups, alkoxy groups, aryl groups, aryloxy groups, alkenyl groups, or acyl groups; even more preferably alkyl groups, aryl groups, aryloxy groups, or alkenyl groups; and even more preferably alkyl groups. The formula weight of these substituents is preferably 15 or more, and preferably 200 or less. Formula weight refers to, for example, a methyl group (-CH ３ If so, the result is 15. These substituents may have further substituents, but it is preferable that they do not have substituents.

[0008] In this specification, "(meth)allyl" refers to both allyl and methallyl, or either of them; "(meth)acrylate" refers to both acrylate and methacrylate, or either of them; "(meth)acrylic" refers to both acrylic and methacrylic, or either of them; and "(meth)acryloyl" refers to both acryloyl and methacryloyl, or either of them.

[0009] In this specification, relative permittivity refers to the ratio of the permittivity of a material to the permittivity of a vacuum. In this specification, relative permittivity may also be simply referred to as "permittivity." Furthermore, unless otherwise specified, relative permittivity refers to the relative permittivity at a frequency of 10 GHz measured according to the cavity resonance perturbation method. In this specification, weight-average molecular weight and number-average molecular weight are measured according to paragraph 0259 of International Publication No. 2024 / 101237 unless otherwise specified.

[0010] In this specification, "resin solids" means maleimide compounds and other thermosetting resins, thermoplastic elastomers, and flame retardants, and does not include other components (fillers, solvents, dispersants, silane coupling agents, catalysts, etc.). If the measurement methods etc. described in the standards shown in this specification differ from year to year, unless otherwise specified, the standards as of January 1, 2024 shall apply. If the measurement methods etc. described in the standards shown in this specification have been abolished as of January 1, 2024, the standards in effect at the time of abolition shall apply.

[0011] The resin composition of this embodiment comprises a thermosetting resin containing a maleimide compound and a thermoplastic elastomer. A 0.1 mm thick dumbbell-shaped No. 6 test piece, molded from the thermoplastic elastomer at 200°C and 3 MPa, is measured according to JIS K 6251 at a tensile speed of 5 mm / min and exhibits an elongation of 200% or more at break. Furthermore, the elongation rate after heating the test piece at 150°C for 3 hours is also 200% or more. The composition is characterized by not containing a radical polymerization initiator. This configuration provides a resin composition capable of providing a cured product in which crack formation after temperature cycling tests is effectively suppressed. In addition, the inherent low dielectric properties (Dk and / or Df) of the cured product of the thermosetting resin such as the maleimide compound and the thermoplastic elastomer can be maintained. Moreover, by using a thermoplastic elastomer whose initial elongation rate is 200% or more and which maintains a high elongation rate of 200% or more even after heating at 150°C for 3 hours, cracks can be suppressed even after temperature cycling tests. Furthermore, the resin composition of this embodiment does not contain a radical polymerization initiator. By not including a radical polymerization initiator, the generation of radicals in the thermoplastic elastomer during the curing of the resin composition, and the reactions between thermoplastic elastomers and between the thermoplastic elastomer and the thermosetting resin that proceed as a result, can be suppressed. Radicals tend to worsen low dielectric properties, but in this embodiment, by not including a radical polymerization initiator, low dielectric properties can be sufficiently maintained. In particular, it is presumed that crack resistance could be further improved by dispersing and compounding the thermoplastic elastomer independently of the thermosetting resin, rather than incorporating it into the thermosetting resin as a component that can impart toughness. Furthermore, the inventors' investigations revealed that in this embodiment, the occurrence of cracks is more likely to be a problem when components that are prone to oxidative degradation under high temperature conditions are used. In this embodiment, it is presumed that crack resistance can be maintained even when components that are prone to oxidative degradation under high temperature conditions are compounded.

[0012] The embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is merely one example of an embodiment of the present invention and is not limited to these.

[0013] <Maleimide Compound> The resin composition of this embodiment contains a maleimide compound. In this embodiment, the maleimide compound is preferably a compound having one or more maleimide groups in one molecule (preferably two or more, more preferably two to twelve, even more preferably two to six, even more preferably two to four, even more preferably two or three, and even more preferably two). In this embodiment, the maleimide compound preferably contains one or more selected from the group consisting of a compound represented by formula (M0), a compound represented by formula (M1), a compound represented by formula (M2), a compound represented by formula (M3), a compound represented by formula (M4), a compound represented by formula (M5), a maleimide compound (M6), a maleimide compound (M7), and a maleimide compound (M8). It is more preferable to include one or more compounds selected from the group consisting of the compounds represented by formula (M1), formula (M2), formula (M3), formula (M4), and formula (M5), it is even more preferable to include one or more compounds selected from the group consisting of the compounds represented by formula (M1), formula (M3), and formula (M5), and it is even more preferable to include the compound represented by formula (M1) and / or the compound represented by formula (M3). When these maleimide compounds are used in printed circuit board materials (e.g., metal foil laminates), excellent heat resistance can be imparted.

[0014] (In formula (M0), R ５１ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group, R ５２ Each of these independently represents a hydrogen atom or a methyl group, n １ (This represents an integer greater than or equal to 1.) R ５１is preferably independently selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and a phenyl group, more preferably a hydrogen atom and / or a methyl group, and even more preferably a hydrogen atom. R ５２ is preferably a methyl group. n １ is preferably an integer of 1 to 10, more preferably an integer of 1 to 5, even more preferably an integer of 1 to 3, still more preferably 1 or 2, and even more preferably 1. Specifically, the following compounds are preferred examples of the formula (M0). In the above formula, R ８ each independently represents a hydrogen atom, a methyl group or an ethyl group, and is preferably a methyl group.

[0015] The compound represented by the formula (M0) may be only one kind or a mixture of two or more kinds. Examples of the mixture include a mixture of compounds in which n １ is different, a mixture of compounds in which the types of substituents of R ５１ and / or R ５２ are different, a mixture of compounds in which the bonding positions (meta-position, para-position, ortho-position) of the maleimide group and the oxygen atom to the benzene ring are different, and a mixture of compounds in which two or more of the above different points are combined. The same applies to the compounds represented by the following formulas (M1) to (M8).

[0016] (In the formula (M1), R Ｍ１ , R Ｍ２ , R Ｍ３ , and R Ｍ４ each independently represents a hydrogen atom or an organic group. R Ｍ５ and R Ｍ６ each independently represents a hydrogen atom or an alkyl group. Ar Ｍ represents a divalent aromatic group. A is an alicyclic group having a ring size of 4 to 6 members. R Ｍ７ and R Ｍ８ are each independently an alkyl group. mx is 1 or 2, and lx is 0 or 1. R Ｍ９ and R Ｍ１０Each of these independently represents either a hydrogen atom or an alkyl group. Ｍ１１ , R Ｍ１２ , R Ｍ１３ , and R Ｍ１４ Each of these independently represents a hydrogen atom or an organic group. Ｍ１５ Each of these 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, a cycloalkyl group having 3 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 halogen atom, a hydroxyl group, or a mercapto group. px represents an integer from 0 to 3. nx represents an integer from 1 to 20.

[0017] R in the formula Ｍ１ , R Ｍ２ , R Ｍ３ , and R Ｍ４ Each of these independently represents a hydrogen atom or an organic group. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably a methyl group, ethyl group, propyl group, or butyl group, with the methyl group being particularly preferred. Ｍ１ and R Ｍ３ Each of these is independently preferably an alkyl group, R Ｍ２ and R Ｍ４ A hydrogen atom is preferred. Ｍ５ and R Ｍ６ Each of these independently represents a hydrogen atom or an alkyl group, with alkyl groups being preferred. Here, alkyl groups having 1 to 12 carbon atoms are preferred, alkyl groups having 1 to 6 carbon atoms are more preferred, and methyl, ethyl, propyl, and butyl groups are even more preferred, with methyl groups being particularly preferred. Ｍ Ar represents a divalent aromatic group, preferably a phenylene group, a naphthalenediyl group, a phenanthrenediyl group, or anthracenediyl group, more preferably a phenylene group, and even more preferably an m-phenylene group. ＭAr may have substituents, preferably alkyl groups, more preferably alkyl groups having 1 to 12 carbon atoms, even more preferably alkyl groups having 1 to 6 carbon atoms, even more preferably methyl groups, ethyl groups, propyl groups, and butyl groups, with methyl groups being particularly preferred. However, Ar Ｍ It is preferable that it is unsubstituted. A is a 4- to 6-membered alicyclic group, and a 5-membered alicyclic group (preferably a group that combines with a benzene ring to form an indan ring) is more preferable. Ｍ７ and R Ｍ８ Each of these is independently an alkyl group, preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group. mx is 1 or 2, preferably 2. lx is 0 or 1, preferably 1. R Ｍ９ and R Ｍ１０ Each of these independently represents a hydrogen atom or an alkyl group, with alkyl groups being more preferred. Here, alkyl groups having 1 to 12 carbon atoms are preferred, alkyl groups having 1 to 6 carbon atoms are more preferred, and methyl, ethyl, propyl, and butyl groups are even more preferred, with methyl groups being particularly preferred. Ｍ１１ , R Ｍ１２ , R Ｍ１３ , and R Ｍ１４ Each of these independently represents a hydrogen atom or an organic group. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably a methyl group, ethyl group, propyl group, or butyl group, with the methyl group being particularly preferred. Ｍ１２ and R Ｍ１３ Each of these is independently preferably an alkyl group, R Ｍ１１ and R Ｍ１４ A hydrogen atom is preferred. Ｍ１５Each of these 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, a cycloalkyl group having 3 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 halogen atom, a hydroxyl group, or a mercapto group, and is preferably an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. px represents an integer from 0 to 3, preferably an integer from 0 to 2, more preferably 0 or 1, and even more preferably 0. nx represents an integer from 1 to 20. nx may be an integer of 10 or less. The resin composition of this embodiment may contain only one compound represented by formula (M1) with at least two or more compounds having different nx values. When two or more types are included, the average value of nx (average number of repeating units) in the compound represented by formula (M1) in the resin composition is preferably 0.92 or higher, more preferably 0.95 or higher, even more preferably 1.0 or higher, and even more preferably 1.1 or higher, in order to obtain a low melting point (low softening point), low melt viscosity, and excellent handling properties. Furthermore, n is preferably 10.0 or less, more preferably 8.0 or less, even more preferably 7.0 or less, even more preferably 6.0 or less, and may also be 5.0 or less. The same applies to formula (M1-1), etc., which will be described later.

[0018] The compound represented by formula (M1) is preferably the compound represented by the following formula (M1-1). (In formula (M1-1), R Ｍ２１ , R Ｍ２２ , R Ｍ２３ , and R Ｍ２４ Each of these independently represents a hydrogen atom or an organic group. Ｍ２５ and R Ｍ２６ Each of these independently represents either a hydrogen atom or an alkyl group. Ｍ２７ , R Ｍ２８ , R Ｍ２９ , and R Ｍ３０ Each of these independently represents a hydrogen atom or an organic group. Ｍ３１ and R Ｍ３２Each of these independently represents either a hydrogen atom or an alkyl group. Ｍ３３ , R Ｍ３４ , R Ｍ３５ , and R Ｍ３６ Each of these independently represents a hydrogen atom or an organic group. Ｍ３７ , R Ｍ３８ , and R Ｍ３９ Each of these independently represents either a hydrogen atom or an alkyl group. nx represents an integer between 1 and 20.

[0019] R in the formula Ｍ２１ , R Ｍ２２ , R Ｍ２３ , and R Ｍ２４ Each of these independently represents a hydrogen atom or an organic group. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably a methyl group, ethyl group, propyl group, or butyl group, and particularly preferably a methyl group. Ｍ２１ and R Ｍ２３ The alkyl group is preferred, R Ｍ２２ and R Ｍ２４ A hydrogen atom is preferred. Ｍ２５ and R Ｍ２６ Each of these independently represents a hydrogen atom or an alkyl group, with alkyl groups being preferred. Here, alkyl groups having 1 to 12 carbon atoms are preferred, alkyl groups having 1 to 6 carbon atoms are more preferred, and methyl, ethyl, propyl, and butyl groups are even more preferred, with methyl groups being particularly preferred. Ｍ２７ , R Ｍ２８ , R Ｍ２９ , and R Ｍ３０ Each of these independently represents a hydrogen atom or an organic group, with hydrogen atoms being preferred. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably a methyl group, ethyl group, propyl group, or butyl group, and particularly preferably a methyl group. Ｍ３１ and R Ｍ３２Each independently represents a hydrogen atom or an alkyl group, and the alkyl group is preferred. The alkyl group here is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, still more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. R Ｍ３３ 、R Ｍ３４ 、R Ｍ３５ 、and R Ｍ３６ each independently represents a hydrogen atom or an organic group. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, still more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. R Ｍ３３ and R Ｍ３６ are preferably hydrogen atoms, and R Ｍ３４ and R Ｍ３５ are preferably alkyl groups. R Ｍ３７ 、R Ｍ３８ 、and R Ｍ３９ each independently represents a hydrogen atom or an alkyl group, and the alkyl group is preferred. The alkyl group here is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, still more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. nx represents an integer of 1 or more and 20 or less. nx may be an integer of 10 or less.

[0020] The compound represented by the formula (M1-1) is preferably the compound represented by the following formula (M1-2). (In the formula (M1-2), R Ｍ２１ 、R Ｍ２２ 、R Ｍ２３ 、and R Ｍ２４ each independently represents a hydrogen atom or an organic group. R Ｍ２５ and R Ｍ２６ each independently represents a hydrogen atom or an alkyl group. R Ｍ２７ 、R Ｍ２８ and R Ｍ２９ 、and R Ｍ３０ each independently represents a hydrogen atom or an organic group. R Ｍ３１ and R Ｍ３２Each of these independently represents either a hydrogen atom or an alkyl group. Ｍ３３ , R Ｍ３４ , R Ｍ３５ , and R Ｍ３６ Each of these independently represents a hydrogen atom or an organic group. Ｍ３７ , R Ｍ３８ , and R Ｍ３９ Each of these independently represents either a hydrogen atom or an alkyl group. nx represents an integer between 1 and 20.

[0021] In formula (M1-2), R Ｍ２１ , R Ｍ２２ , R Ｍ２３ , R Ｍ２４ , R Ｍ２５ , R Ｍ２６ , R Ｍ２７ , R Ｍ２８ , R Ｍ２９ , R Ｍ３０ , R Ｍ３１ , R Ｍ３２ , R Ｍ３３ , R Ｍ３４ , R Ｍ３５ , R Ｍ３６ , R Ｍ３７ , R Ｍ３８ , R Ｍ３９ , and nx are R in equation (M1-1), respectively. Ｍ２１ , R Ｍ２２ , R Ｍ２３ , R Ｍ２４ , R Ｍ２５ , R Ｍ２６ , R Ｍ２７ , R Ｍ２８ , R Ｍ２９ , R Ｍ３０ , R Ｍ３１ , R Ｍ３２ , R Ｍ３３ , R Ｍ３４ , R Ｍ３５ , R Ｍ３６ , R Ｍ３７ , R Ｍ３８ , R Ｍ３９ , and are synonymous with nx, and the preferred range is also similar.

[0022] The compound represented by formula (M1-1) is preferably the compound represented by the following formula (M1-3), and more preferably the compound represented by the following formula (M1-4). (In equation (M1-3), nx represents an integer between 1 and 20.) nx may also be an integer less than or equal to 10. (In equation (M1-4), nx represents an integer between 1 and 20.) nx may also be an integer less than or equal to 10.

[0023] The molecular weight of the compound represented by formula (M1) is preferably 500 or more, more preferably 600 or more, and even more preferably 700 or more. Setting it above the lower limit tends to further improve the low dielectric properties and low water absorption of the resulting cured product. Furthermore, the molecular weight of the compound represented by formula (M1) is preferably 10,000 or less, more preferably 9,000 or less, even more preferably 7,000 or less, even more preferably 5,000 or less, and even more preferably 4,000 or less. Setting it below the upper limit tends to further improve the heat resistance and handling properties of the resulting cured product.

[0024] Further details of the compound represented by formula (M1) can be found in International Publication No. 2020-217679, which is incorporated herein by reference.

[0025] (In formula (M2), R ５４ Each of these independently represents a hydrogen atom or a methyl group, n ４ (This represents an integer greater than or equal to 1.) R ５４ It is preferably a hydrogen atom. ４ n is preferably an integer from 1 to 10, more preferably an integer from 1 to 5, even more preferably an integer from 1 to 3, even more preferably 1 or 2, and may be 1. The compound represented by formula (M2) is n ４ It may be a mixture of different compounds, and is preferable. Also, as mentioned in the section on the compound represented by formula (M0), it may be a mixture of compounds with other parts that are different.

[0026] (In formula (M3), R ５５ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group, n ５ (This represents an integer between 1 and 10.)５５ Each of these is preferably independently selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and a phenyl group, more preferably a hydrogen atom and / or a methyl group, and even more preferably a hydrogen atom. ５ n is preferably an integer between 1 and 5, more preferably an integer between 1 and 3, and even more preferably 1 or 2. The compound represented by formula (M3) is n ５ It may be a mixture of different compounds, and is preferable. Also, as mentioned in the section on the compound represented by formula (M0), it may be a mixture of compounds with other parts that are different.

[0027] (In formula (M4), R ５６ Each of these independently represents a hydrogen atom, a methyl group, or an ethyl group, and R ５７ Each of these independently represents either a hydrogen atom or a methyl group.) An example of a compound represented by formula (M4) is R ５６ Each is independently a methyl group or an ethyl group, R ５７ R is a methyl group. ５６ It is more preferable that the two benzene rings are a methyl group and an ethyl group, respectively. Another example of a compound represented by formula (M4) is R ５６ Each is independently a methyl group or an ethyl group, R ５７ is a hydrogen atom. Another example of a compound represented by formula (M4) is R ５６ and R ５７ The fact is that it is a hydrogen atom.

[0028] (In formula (M5), R ５８ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group, R ５９ Each of these independently represents a hydrogen atom or a methyl group, n ６ (This represents an integer greater than or equal to 1.) R ５８Each of these is preferably independently selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and a phenyl group, and more preferably a hydrogen atom, a methyl group, or an ethyl group. ５８ and R ５９ One example is that they are all hydrogen atoms. ５８ and R ５９ Another example is R ５８ is a methyl group, R ５９ It is a hydrogen atom. ５８ and R ５９ Another example is R ５８ is an ethyl group, R ５９ n is a hydrogen atom. ６ n is preferably an integer from 1 to 10, more preferably an integer from 1 to 5, even more preferably an integer from 1 to 3, even more preferably 1 or 2, and may be 1. The compound represented by formula (M5) is n ６ It may be a mixture of different compounds, and is preferable. Also, as mentioned in the section on the compound represented by formula (M0), it may be a mixture of compounds with other parts that are different.

[0029] Maleimide compounds (M6) are compounds having the structure represented by formula (M6) and maleimide groups at both ends of the molecular chain. (In formula (M6), R ６１ R represents a linear or branched alkylene group having 1 to 16 carbon atoms, or a linear or branched alkenylene group having 2 to 16 carbon atoms. ６２ R represents a linear or branched alkylene group having 1 to 16 carbon atoms, or a linear or branched alkenylene group having 2 to 16 carbon atoms. ６３ Each independently represents a linear or branched alkyl group having 1 to 16 carbon atoms, or a linear or branched alkenyl group having 2 to 16 carbon atoms. Each independently represents an integer from 0 to 10.) Details of the maleimide compound (M6) and its preparation method can be found in paragraphs 0061 to 0066 of International Publication No. 2020 / 262577, which are incorporated herein by reference.

[0030] Maleimide compound (M7) is a maleimide compound obtained by using as reaction raw materials (1) an aromatic amine compound (a1) having 1 to 3 alkyl groups on the aromatic ring, an aromatic divinyl compound (a2) having 2 ethenyl groups, and maleic anhydride. Preferably, maleimide compound (M7) is a compound having the structure represented by formula (M7). (In the above formula (M7), R １ Each of these independently represents an alkyl group having 1 to 10 carbon atoms, and R ２ Each of these independently represents an alkyl group having 1 to 10 carbon atoms, an 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. ３ , R ４ , R ５ and R ６ Each of these independently represents a hydrogen atom or a methyl group, and R ３ and R ４ One side is a hydrogen atom, and the other side is a methyl group, R ５ and R ６ One side is a hydrogen atom, and the other side is a methyl group, X １ These are expressed independently as follows (x): (In formula (x), R ７ and R ８ Each of these independently represents a hydrogen atom or a methyl group, and R ７ and R ８ One side is a hydrogen atom, and the other side is a methyl group, R ９ Each of these independently represents an alkyl group having 1 to 10 carbon atoms, an 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, where t represents an integer from 0 to 4. ) represents a substituent represented by X １ X per benzene ring to which is bonded １(This is the average number of substitutions, representing numbers from 0 to 4, where p represents an integer from 1 to 3, q ​​represents an integer from 0 to 4, and k represents an integer from 1 to 100.) R １ The alkyl group is preferably a C1-C5 alkyl group, more preferably a methyl group and an ethyl group, and even more preferably an ethyl group. ２ The alkyl group is preferably a C1-C5 alkyl group, and more preferably a methyl group and an ethyl group. ３ , R ４ , R ５ and R ６ R ３ and R ４ One side is a hydrogen atom, and the other side is a methyl group, R ５ and R ６ Preferably, one of the elements is a hydrogen atom and the other is a methyl group. Preferably, p is 1. Preferably, q is an integer from 0 to 2, more preferably 0 or 1, and even more preferably 1. Preferably, r is 0. Preferably, k is an integer from 1 to 50, more preferably an integer from 1 to 10, and even more preferably an integer from 1 to 4. In this embodiment, the maleimide compound (M7) preferably consists only of the structure represented by formula (M7) and a terminal group, and the terminal group is preferably a hydrogen atom. An example of the maleimide compound (M7) is shown below. n is the same as k above.

[0031] Details of the maleimide compound (M7) used in this embodiment can be found in Japanese Patent No. 7160151, which is incorporated herein by reference.

[0032] The maleimide compound (M8) is a bismaleimide compound having a hydrocarbon group in which eight or more atoms are linked in a linear chain, and is preferably a compound represented by formula (M8). Such maleimide compounds (M8) tend to have higher stress relaxation ability, and as a result, the thermal expansion coefficient of the resulting cured product tends to be lower, and the electrical properties such as dielectric constant and dielectric loss tangent tend to be better. (In formula (M8), R １ and R ３Each of these independently represents a hydrocarbon group in which eight or more atoms are linked in a linear chain, and R ２ Each of these independently represents a substituted or unsubstituted cyclic hydrocarbon group that may contain 4 to 10 heteroatoms constituting the ring, and n represents a number from 0 to 10.

[0033] In equation (M8), R １ and R ３ However, it is an octylene group, R ２ However, it is preferable that the cycloalkylene group has an alkyl group having 6 to 8 carbon atoms as a substituent.

[0034] For maleimide compounds (M8), refer to the descriptions in paragraphs 0014 to 0022 of Japanese Patent Publication No. 2018-083893 and paragraphs 0012 to 0022 of Japanese Patent Publication No. 2018-090728, the contents of which are incorporated herein by reference.

[0035] Furthermore, maleimide compounds (maleimide compound (M9)) described in Japanese Patent Publication No. 2024-004392 and Japanese Patent Publication No. 2024-161436 can also be used, and this is incorporated herein by reference.

[0036] Maleimide compounds may be manufactured by known methods or commercially available products may be used. Examples of commercially available products include "BMI-80" manufactured by K.I. Chemicals Co., Ltd. as a compound represented by formula (M0), "NE-X-9470S" and "NE-X-9480S" manufactured by DIC Corporation as compounds represented by formula (M1), "BMI-2300" manufactured by Yamato Chemical Industries Co., Ltd. as a compound represented by formula (M2), "MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd. as a compound represented by formula (M3), and a compound represented by formula (M4) Examples of compounds include "BMI-70" manufactured by Kei-I Kasei Co., Ltd., "BMI-5100" manufactured by Yamato Kasei Kogyo Co., Ltd., "MIR-5000" manufactured by Nippon Kayaku Co., Ltd. as a compound represented by formula (M5), "MIZ-001" manufactured by Nippon Kayaku Co., Ltd. as a maleimide compound (M6), "NE-X-9500" manufactured by DIC Corporation as a maleimide compound (M7), "SFR" manufactured by Resonac Corporation, and "BMI-689", "BMI-1500", "BMI-2500", "BMI-3000", and "BMI-5000" manufactured by DESIGNER MOLECULES INC. as maleimide compounds (M9) as "NE-X-9600" manufactured by DIC Corporation.

[0037] Other maleimide compounds include, for example, N-phenylmaleimide, N-cyclohexylmaleimide, oligomers of phenylmethanemaleimide, m-phenylenebismaleimide, 2,2-bis(4-(4-maleimidophenoxy)-phenyl)propane, 4-methyl-1,3-phenylenebismaleimide, 1,6-bismaleimide-(2,2,4-trimethyl)hexane, 4,4'-diphenyletherbismaleimide, 4,4'-diphenylsulfonebismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, and their prepolymers, as well as prepolymers of these maleimides and amines. In addition to the above, the compounds described in paragraphs 0051 to 0068 of International Publication No. 2020 / 262577 can also be referenced, and this content is incorporated herein.

[0038] The maleimide group equivalent of the maleimide compound is preferably 130 g / eq. or more, more preferably 150 g / eq. or more, even more preferably 170 g / eq. or more, even more preferably 180 g / eq. or more, even more preferably 200 g / eq. or more, even more preferably 290 g / eq. or more, and also preferably 1000 g / eq. or less, more preferably 800 g / eq. or less, even more preferably 700 g / eq. or less, even more preferably 600 g / eq. or less, and even more preferably 500 g / eq. or less. Setting it above the lower limit tends to result in better low dielectric properties (Dk and / or Df, particularly Df) of the resulting cured product. Setting it below the upper limit tends to result in better peel strength of the resulting cured product.

[0039] The lower limit of the maleimide compound content in the resin composition of this embodiment is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more, depending on the application, etc., it may be 25 parts by mass or more, 30 parts by mass or more, 33 parts by mass or more, 40 parts by mass or more, or 45 parts by mass or more. When the maleimide compound content is 1 part by mass or more, the flame resistance of the resulting cured product tends to improve. The upper limit of the maleimide compound content is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, even more preferably 60 parts by mass or less, and even more preferably 55 parts by mass or less, depending on the application, etc. When the maleimide compound content is 90 parts by mass or less, the peel strength and low water absorption tend to improve. The resin composition in this embodiment may contain only one maleimide compound or two or more. When two or more are included, it is preferable that the total amount is within the above range.

[0040] <Thermosetting resins other than maleimide compounds> The resin composition of this embodiment may also contain thermosetting resins other than maleimide compounds. The thermosetting resin other than maleimide compounds preferably contains at least one selected from the group consisting of aromatic resins having a carbon-carbon double bond at the terminal, cyanate ester compounds, (meth)allyl compounds, (meth)acrylate compounds, epoxy compounds, phenol compounds, oxetane compounds, benzoxazine compounds, arylcyclobutene compounds, perfluorovinyl ether resins, polyimide compounds, and compounds having a vinylene group, and more preferably contains a polyphenylene ether compound having a carbon-carbon unsaturated double bond at the terminal.

[0041] In this embodiment, the total content of thermosetting resins other than the maleimide compound in the resin composition is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and may be 15 parts by mass or more, and also preferably 90 parts by mass or less, more preferably 70 parts by mass or less, even more preferably 50 parts by mass or less, even more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less. Setting the content above the lower limit tends to further improve the heat resistance and peel strength of the resulting cured product. Setting the content below the upper limit tends to further improve the low dielectric properties (Dk and / or Df) of the resulting cured product. In this embodiment, the resin composition may contain only one type of thermosetting resin other than the maleimide compound, or it may contain two or more types. When two or more types are included, it is preferable that the total amount is within the above range.

[0042] <<Aromatic Resins Having Carbon-Carbon Double Bonds at the Terminals>> Aromatic resins having carbon-carbon double bonds at the terminals are, for example, compounds that have carbon-carbon double bonds at the terminals and contain aromatic rings, and are compounds that harden with heat. Aromatic resins having carbon-carbon double bonds at the terminals tend to have low dielectric constant and low dielectric loss tangent due to their low polarity skeleton. Specifically, aromatic resins having carbon-carbon double bonds at the terminals preferably include one or more selected from the group consisting of polyphenylene ether compounds having carbon-carbon unsaturated double bonds at the terminals, polymers having structural units represented by formula (V), and resins having terminal groups represented by formula (T1) and having an indan skeleton. It is more preferable to include polyphenylene ether compounds having carbon-carbon unsaturated double bonds at the terminals and / or resins having terminal groups represented by formula (T1) and having an indan skeleton, and it is even more preferable to include polyphenylene ether compounds having carbon-carbon unsaturated double bonds at the terminals. Polyphenylene ether compounds having carbon-carbon unsaturated double bonds at their terminals are readily miscible with thermoplastic elastomers (A) and also readily miscible with thermosetting resins containing maleimide compounds. Therefore, even when using thermoplastic elastomers (A) that are difficult to miscible with thermosetting resins, the components of the resin composition can be thoroughly mixed, making it possible to effectively exhibit the desired properties.

[0043] In this embodiment, if the resin composition contains an aromatic resin having a carbon-carbon double bond at its end, the content is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, even more preferably 10 parts by mass or more, even more preferably 12 parts by mass or more, and also preferably 90 parts by mass or less, more preferably 70 parts by mass or less, even more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, and depending on the application, even more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less. By setting the content of the aromatic resin having a carbon-carbon double bond at its end to above the lower limit, the compatibility and heat resistance of the thermosetting resin tend to improve further. Also, by setting the content of the aromatic resin having a carbon-carbon double bond at its end to below the upper limit, the low thermal expansion properties tend to improve further. In this embodiment, the resin composition may contain only one type of aromatic resin having a carbon-carbon double bond at its end, or it may contain two or more types. If two or more types are included, it is preferable that the total amount falls within the above range.

[0044] <<<Polyphenylene ether compounds having carbon-carbon unsaturated double bonds at the terminals>>> The resin composition in this embodiment preferably contains a polyphenylene ether compound having carbon-carbon unsaturated double bonds at the terminals, and more preferably contains a polyphenylene ether compound having two or more carbon-carbon unsaturated double bonds at the terminals. The polyphenylene ether compound having two or more carbon-carbon unsaturated double bonds at the terminals preferably contains a polyphenylene ether compound having two or more groups represented by the formula (Rx-1) described later (preferably vinylbenzyl groups) at the terminals. The details of these will be explained below.

[0045] Examples of polyphenylene ether compounds having a carbon-carbon unsaturated double bond at the terminal include compounds having a phenylene ether skeleton represented by the following formula (X1).

[0046] (In formula (X1), R ２４ , R２５ , R ２６ , and, R ２７ (These may be the same or different characters, and represent an alkyl group, aryl group, halogen atom, or hydrogen atom having six or fewer carbon atoms.)

[0047] A polyphenylene ether compound having a carbon-carbon unsaturated double bond at its terminus is given by formula (X2): (In formula (X2), R ２８ , R ２９ , R ３０ , R ３４ , and, R ３５ R may be the same or different, and represents an alkyl group or phenyl group having 6 or fewer carbon atoms. ３１ , R ３２ , and, R ３３ These may be the same or different, and are a hydrogen atom, an alkyl group having 6 or fewer carbon atoms, or a phenyl group.) A repeating unit represented by formula (X3): (In formula (X3), R ３６ , R ３７ , R ３８ , R ３９ , R ４０ , R ４１ , R ４２ , and, R ４３ ) may be the same or different, and is a hydrogen atom, an alkyl group having 6 or fewer carbon atoms, or a phenyl group. -A- is a straight, branched, or cyclic divalent hydrocarbon group having 20 or fewer carbon atoms. ) may further contain repeating units represented by ).

[0048] The polyphenylene ether compound having a carbon-carbon unsaturated double bond at its terminus is preferably a modified polyphenylene ether compound (hereinafter sometimes referred to as "modified polyphenylene ether compound (g)") in which part or all of the terminus is functionalized with an ethylenically unsaturated group, and more preferably a modified polyphenylene ether compound having two or more groups selected from the group consisting of (meth)acryloyl groups and vinylbenzyl groups at its terminus. By employing such a modified polyphenylene ether compound (g), it is possible to further reduce the dielectric loss tangent (Df) of the cured resin composition and to improve water absorption and peel strength. These modified polyphenylene ether compounds (g) may be used individually or in combination of two or more.

[0049] Examples of modified polyphenylene ether compounds (g) include polyphenylene ether compounds represented by formula (OP). (In formula (OP), X represents an aromatic group, and -(Y-O)) ｎ１ The hyphen (-) represents a polyphenylene ether structure, where n1 is an integer from 1 to 100, and n2 is an integer from 1 to 4. Rx is a group represented by formula (Rx-1) or formula (Rx-2). (In equations (Rx-1) and (Rx-2), R １ , R ２ , and, R ３ Each of these independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. * represents the bonding site with the oxygen atom. Mc independently represents a hydrocarbon group with 1 to 12 carbon atoms. z represents an integer from 0 to 4. r represents an integer from 0 to 6.

[0050] The aromatic group represented by X may or may not have substituents on the benzene ring, but it is preferable that it does. If substituents are present, the substituent Z described later can be an example, but it is preferable that it is at least one selected from the group consisting of alkyl groups, aryl groups, and halogen atoms having 6 or fewer carbon atoms, more preferably an alkyl group having 3 or fewer carbon atoms, and even more preferably a methyl group. Also, the -(Y-O)n １The polyphenylene ether structure represented by - may or may not have substituents on the benzene ring, but it is preferable that it does. If substituents are present, the substituent Z described above can be exemplified, but it is preferably an alkyl group or phenyl group having 6 or fewer carbon atoms, more preferably an alkyl group having 3 or fewer carbon atoms, and even more preferably a methyl group. １ and / or n ２ If n is an integer greater than or equal to 2, １ individual constituent units (Y-O) and / or n ２ Each constituent unit may be identical or different. ２ The number is preferably 2 or more, and more preferably 2.

[0051] In equations (Rx-1) and (Rx-2), R １ , R ２ , and, R ３ Each of these independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. １ A hydrogen atom or an alkyl group is preferred, a hydrogen atom or a methyl group is more preferred, and a hydrogen atom is even more preferred. ２ and R ３ Each of these is independently preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. １ , R ２ , and, R ３ The number of carbon atoms in the alkyl group, alkenyl group, or alkynyl group is preferably 5 or less, and more preferably 3 or less.

[0052] In formula (Rx-1), r represents an integer from 0 to 6, and may be an integer of 1 or more, preferably an integer of 5 or less, more preferably an integer of 4 or less, even more preferably an integer of 3 or less, even more preferably 1 or 2, and even more preferably 1.

[0053] In formula (Rx-1), Mc independently represents a hydrocarbon group having 1 to 12 carbon atoms, preferably a hydrocarbon group having 1 to 10 carbon atoms, more preferably a linear or branched alkyl group having 1 to 10 carbon atoms, even more preferably a methyl group, ethyl group, isopropyl group, isobutyl group, t-butyl group, pentyl group, octyl group, or nonyl group, and even more preferably a methyl group, ethyl group, isopropyl group, isobutyl group, or t-butyl group. In formula (Rx-1), z represents an integer from 0 to 4, preferably an integer from 0 to 3, more preferably an integer from 0 to 2, even more preferably 0 or 1, and even more preferably 0.

[0054] A specific example of the group represented by formula (Rx-1) is the vinylbenzyl group, and a specific example of the group represented by formula (Rx-2) is the (meth)acryloyl group.

[0055] The resin composition in this embodiment is a polyphenylene ether compound having a carbon-carbon unsaturated double bond at its terminus, and is preferably a compound represented by formula (OP), which may include both a polyphenylene ether compound having a group represented by formula (Rx-1) and a polyphenylene ether compound having a group represented by formula (Rx-2).

[0056] Examples of modified polyphenylene ether compounds (g) include the compound represented by formula (OP-1). (In formula (OP-1), X represents an aromatic group, -(Y-O)n ２ - represents the polyphenylene ether structure, R １ , R ２ , and, R ３ Each of these independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group, and n １ n represents an integer from 0 to 6, and n ２ n represents an integer between 1 and 100, and n ３(where represents an integer from 1 to 4.) The aromatic group represented by X may or may not have substituents on the benzene ring, but it is preferable that it does. If substituents are present, the substituent Z described above can be exemplified, but it is preferable that it be at least one selected from the group consisting of alkyl groups, aryl groups, and halogen atoms having 6 or fewer carbon atoms, more preferably an alkyl group having 3 or fewer carbon atoms, and even more preferably a methyl group. Also, the -(Y-O)n ２ The polyphenylene ether structure represented by - may or may not have substituents on the benzene ring, but it is preferable that it does. If substituents are present, the substituent Z described above can be exemplified, but it is preferably an alkyl group or phenyl group having 6 or fewer carbon atoms, more preferably an alkyl group having 3 or fewer carbon atoms, and even more preferably a methyl group. ２ and / or n ３ If n is an integer greater than or equal to 2, ２ individual constituent units (Y-O) and / or n ３ Each constituent unit may be identical or different. ３ The number is preferably 2 or more, and more preferably 2.

[0057] In this embodiment, the modified polyphenylene ether compound (g) is preferably a compound represented by formula (OP-2). Here, -(O-X-O)- is equation (OP-3): (In formula (OP-3), R ４ , R ５ , R ６ , R ９ , R １０ , and, R １１ These may be the same or different alkyl groups or phenyl groups having 6 or fewer carbon atoms. ７ , and, R ８ These may be the same or different, and are a hydrogen atom, an alkyl group having 6 or fewer carbon atoms, or a phenyl group.) and / or formula (OP-4): (In formula (OP-4), R １２ , R １３ , R １４ , R１５ , R １６ , R １７ , R １８ , and, R １９ (These may be the same or different, and are a hydrogen atom, an alkyl group having 6 or fewer carbon atoms, or a phenyl group.) -A- is a linear, branched, or cyclic divalent hydrocarbon group having 20 or fewer carbon atoms.

[0058] Also, -(Y-O)- is given by equation (OP-5): (In formula (OP-5), R ２０ , R ２１ These may be the same or different alkyl groups or phenyl groups having 6 or fewer carbon atoms. ２２ , R ２３ These may be the same or different, and are a hydrogen atom, an alkyl group having 6 or fewer carbon atoms, or a phenyl group. It is preferable that it be represented as ). In particular, R ２０ and R ２１ Each of these groups independently has one or more methyl and / or cyclohexyl groups. This increases the rigidity of the resulting resin molecule. Since molecules with high rigidity have lower mobility than molecules with low rigidity, the relaxation time during dielectric relaxation is longer, resulting in excellent low dielectric properties (Dk and / or Df, especially Dk), which is therefore preferable. An example of formula (OP-5) is shown below. For polyphenylene ether compounds having the above structure, please refer to the description in Japanese Patent Application Publication No. 2019-194312, which is incorporated herein by reference.

[0059] In formula (OP-2), a and b each independently represent integers from 0 to 100, and at least one of a and b is an integer from 1 to 100. Preferably, a and b are integers from 0 to 50, more preferably from 1 to 30, and preferably from 1 to 10. When a and / or b are integers of 2 or more, the 2 or more -(Y-O)- may each independently consist of one type of structure, or two or more structures may be arranged in a block or randomly. Furthermore, when multiple compounds represented by formula (OP-2) are included, the average value of a is preferably 1 < a < 10, and the average value of b is preferably 1 < b < 10.

[0060] Examples of the -A- in formula (OP-4) include, but are not limited to, divalent organic groups such as methylene group, ethylidene group, 1-methylethylidene group, 1,1-propyridene group, 1,4-phenylenebis(1-methylethylidene) group, 1,3-phenylenebis(1-methylethylidene) group, cyclohexylidene group, phenylmethylene group, naphthylmethylene group, and 1-phenylethylidene group.

[0061] Among the compounds represented by the above formula (OP-2), R ４ , R ５ , R ６ , R ９ , R １０ , R １１ , R １２ , R １３ , R １４ , R １５ , R １６ , R １７ , R １８ , R １９ , R ２０ , and, R ２１ is an alkyl group having 3 or fewer carbon atoms, R ７ , R ８ , R ２２ , and, R ２３A polyphenylene ether compound in which is a hydrogen atom or an alkyl group having 3 or fewer carbon atoms is preferred, and in particular, the -(O-X-O)- represented by formula (OP-3) or formula (OP-4) is preferably formula (OP-9), formula (OP-10), and / or formula (OP-11), and the -(Y-O)- represented by formula (OP-5) is preferably formula (OP-12) or formula (OP-13). When a and / or b are integers of 2 or more, the 2 or more -(Y-O)- may each independently be a structure in which two or more of formula (OP-12) and / or formula (OP-13) are arranged, or a structure in which formula (OP-12) and formula (OP-13) are arranged in a block or randomly.

[0062] (In formula (OP-10), R ４４ , R ４５ , R ４６ , and, R ４７ A is a hydrogen atom or a methyl group, and may be the same or different. B is a straight, branched, or cyclic divalent hydrocarbon group with 20 or fewer carbon atoms. Specific examples of B are the same as the specific examples of A in formula (OP-4). (In formula (OP-11), -B- is a straight-chain, branched, or cyclic divalent hydrocarbon group having 20 or fewer carbon atoms.) Specific examples of -B- are the same as the specific examples of -A- in formula (OP-4).

[0063] The modified polyphenylene ether compound (g) is more preferably a compound represented by formula (OP-14) and / or a compound represented by formula (OP-15), and even more preferably a compound represented by formula (OP-15). (In formula (OP-14), a and b each independently represent integers from 0 to 100, and at least one of a and b is an integer from 1 to 100.) In formula (OP-14), a and b are each independently equivalent to a and b in formula (OP-2), and the preferred ranges are also the same. (In formula (OP-15), a and b each independently represent integers from 0 to 100, and at least one of a and b is an integer from 1 to 100.) In formula (OP-15), a and b are each independently equivalent to a and b in formula (OP-2), and the preferred ranges are also the same.

[0064] Furthermore, the polyphenylene ether compound used in this embodiment may also be a compound represented by formula (OP-16). (In formula (OP-16), a and b each independently represent integers between 0 and 100, and at least one of a and b is an integer between 1 and 100.)

[0065] Polyphenylene ether compounds having a carbon-carbon unsaturated double bond at the terminal may be produced by known methods or commercially available products may be used. Examples of commercially available products include SA9000 from SABIC Innovative Plastics, which is a modified polyphenylene ether compound with a methacryloyl group at the terminal. Examples of modified polyphenylene ether compounds with a vinylbenzyl group at the terminal include OPE-2St1200 and OPE-2St2200 from Mitsubishi Gas Chemical Company. Furthermore, as a modified polyphenylene ether compound with a vinylbenzyl group at the terminal, it is also possible to use a polyphenylene ether compound with a hydroxyl group at the terminal, such as SA90 from SABIC Innovative Plastics, which has been modified to have a vinylbenzyl group using vinylbenzyl chloride or the like.

[0066] Further details regarding polyphenylene ether compounds having a terminal carbon-carbon unsaturated double bond can be found in Japanese Patent Publication No. 2006-028111, Japanese Patent Publication No. 2018-131519, International Publication No. 2019-138992, and International Publication No. 2022-054303, the contents of which are incorporated herein by reference.

[0067] The number-average molecular weight in polystyrene terms of a polyphenylene ether compound having a carbon-carbon unsaturated double bond at its terminus (preferably a modified polyphenylene ether compound (g)) is preferably 500 to 3,000, as determined by GPC (gel permeation chromatography). A number-average molecular weight of 500 or more tends to further suppress stickiness when the resin composition in this embodiment is formed into a coating film. Furthermore, a number-average molecular weight of 3,000 or less tends to further improve solubility in solvents. In addition, the weight-average molecular weight in polystyrene terms of a polyphenylene ether compound having a carbon-carbon unsaturated double bond at its terminus (preferably a modified polyphenylene ether compound (g)) as determined by GPC is preferably 800 to 10,000, and more preferably 800 to 5,000. When the weight-average molecular weight is above the lower limit, the relative permittivity (Dk) and dielectric loss tangent (Df) of the cured resin composition tend to be lower, and when it is below the upper limit, the solubility in solvents, low viscosity, and moldability of the resin composition when producing varnishes, etc., as described later tend to be improved. Furthermore, for polyphenylene ether compounds having carbon-carbon unsaturated double bonds at the terminals (preferably modified polyphenylene ether compounds (g)), the equivalent amount of the terminal carbon-carbon unsaturated double bonds is preferably 400 to 5000 g per carbon-carbon unsaturated double bond, and more preferably 400 to 2500 g. When the equivalent amount of the terminal carbon-carbon unsaturated double bonds is above the lower limit, the relative permittivity (Dk) and dielectric loss tangent (Df) of the cured resin composition tend to be lower, and when it is below the upper limit, the solubility in solvents, low viscosity, and moldability of the resin composition tend to be improved.

[0068] The functional group equivalent (equivalent of carbon-carbon unsaturated double bond) in polyphenylene ether compounds having a carbon-carbon unsaturated double bond at the terminal is calculated by determining the amount of double bond from the measurement results using an infrared spectrometer and then calculating the reciprocal. The double bond equivalent [g / eq.] was determined as follows: The weight of the polyphenylene ether powder was weighed and recorded. After placing this powder in a volumetric flask, the measurement sample was prepared by making up the volume with carbon disulfide to a predetermined amount. This sample solution was placed in a measurement cell and set in an infrared spectrophotometer (FT / IR-4600, manufactured by JASCO Corporation). Subsequently, infrared spectroscopic measurement of the sample solution was performed. In the case of vinyl groups in polyphenylene ether compounds, the value was 905 cm⁻¹. －１ Record the peak area of ​​the spectrum in the vicinity. When the carbon-carbon unsaturated double bond is a methacrylic group, the peak area is 1640 cm⁻¹. －１ The peak area of ​​the spectrum in the vicinity is recorded. From this area value and the calibration curve, the double bond concentration [mol / L] is determined as a measured value. Next, the double bond equivalent is calculated using the following formula: Double bond equivalent [g / eq.] = Powder weight in the measurement sample [g] / Double bond concentration [mol / L] × Volume of measurement sample liquid [L] The functional group equivalent of other thermosetting resins other than polyphenylene ether compounds having carbon-carbon unsaturated double bonds at the terminals can also be measured following the above method. However, for compounds (monomers) that can be expressed by a single molecular weight, the value obtained by (theoretical molecular weight ÷ number of functional groups) shall be used preferentially. If two or more other thermosetting resins are included, the functional group equivalent of the other thermosetting resins shall be the sum (weighted average) of the values ​​obtained by multiplying the functional group equivalent of each other thermosetting resin by its mass fraction.

[0069] In this embodiment, if the resin composition contains a polyphenylene ether compound having a carbon-carbon unsaturated double bond at its terminus, the lower limit of its content is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 7 parts by mass or more, even more preferably 10 parts by mass or more, even more preferably 12 parts by mass or more, and also preferably 90 parts by mass or less, more preferably 70 parts by mass or less, even more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less. Depending on the application, it may also be 30 parts by mass or less, 25 parts by mass or less, or 20 parts by mass or less. By setting the content of the polyphenylene ether compound having a carbon-carbon unsaturated double bond at its terminus to be above the lower limit, the moldability of the resin composition, the heat resistance, low water absorption, and low dielectric properties (Dk and / or Df) of the resulting cured product tend to be further improved. By keeping the content of polyphenylene ether compounds having carbon-carbon unsaturated double bonds at their ends below the aforementioned upper limit, the low dielectric properties (especially low dielectric loss tangent) and chemical resistance of the resulting cured product tend to improve. The resin composition in this embodiment may contain only one type of polyphenylene ether compound having carbon-carbon unsaturated double bonds at its ends, or it may contain two or more types. When two or more types are included, it is preferable that the total amount is within the above range.

[0070] <<<Polymer having a constituent unit represented by formula (V)>>> The resin composition in this embodiment may contain a polymer having a constituent unit represented by formula (V). By including a polymer having a constituent unit represented by formula (V), a resin composition with excellent low dielectric properties (low relative permittivity, low dielectric loss tangent) can be obtained. (In formula (V), Ar represents an aromatic hydrocarbon linking group. * represents the bond position.) An aromatic hydrocarbon linking group may consist only of an aromatic hydrocarbon which may have substituents, or it may consist of a combination of an aromatic hydrocarbon which may have substituents and another linking group, and it is preferable that it consists only of an aromatic hydrocarbon which may have substituents. The substituents that the aromatic hydrocarbon may have include substituent Z (for example, alkyl groups having 1 to 6 carbon atoms, alkenyl groups having 2 to 6 carbon atoms, alkynyl groups having 2 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, hydroxyl groups, amino groups, carboxyl groups, halogen atoms, etc.). Furthermore, it is preferable that the above aromatic hydrocarbon does not have substituents. The aromatic hydrocarbon linking group is usually a divalent linking group.

[0071] Aromatic hydrocarbon linking groups specifically include phenylene groups, naphthalenediyl groups, anthracenediyl groups, phenanthrenediyl groups, biphenyldiyl groups, and fluoroorangeyl groups, which may have substituents, with the phenylene group being preferred among them, which may have substituents. The substituent Z mentioned above is an example of a substituent, but it is preferable that groups such as the phenylene group mentioned above do not have substituents.

[0072] A polymer having a structural unit represented by formula (V) more preferably contains at least one of the structural units represented by formula (V1), formula (V2), and formula (V3). * in the following formulas represents a bond position. Furthermore, the structural units represented by formulas (V1) to (V3) are sometimes collectively referred to as "structural unit (a)".

[0073] In formulas (V1) to (V3), L １The is an aromatic hydrocarbon linking group (preferably with 6 to 22 carbon atoms, more preferably with 6 to 18 carbon atoms, and even more preferably with 6 to 10 carbon atoms). Specifically, examples include phenylene group, naphthalenediyl group, anthracenediyl group, phenanthrenediyl group, biphenyldiyl group, and fluoradiyl group, which may have substituents, and among these, the phenylene group, which may have substituents, is preferred. The substituent is exemplified by the substituent Z mentioned above, but it is preferable that groups such as the phenylene group mentioned above do not have substituents. The compound that forms the constituent unit (a) is preferably a divinyl aromatic compound, such as divinylbenzene, bis(1-methylvinyl)benzene, divinylnaphthalene, divinylanthracene, divinylbiphenyl, and divinylphenanthrene. Among these, divinylbenzene is particularly preferred. One of these divinyl aromatic compounds may be used, or two or more may be used as needed. That is, it is preferable that the constituent unit (a) is a constituent unit derived from a divinyl aromatic compound.

[0074] As described above, the polymer having the constituent unit represented by formula (V) may be a homopolymer of the compound forming the constituent unit (a), or it may be a copolymer with a constituent unit derived from another monomer. When the polymer having the constituent unit represented by formula (V) is a copolymer, the copolymerization ratio is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, and may be 15 mol% or more. The upper limit is preferably 90 mol% or less, more preferably 85 mol% or less, even more preferably 80 mol% or less, even more preferably 70 mol% or less, even more preferably 60 mol% or less, even more preferably 50 mol% or less, even more preferably 40 mol% or less, even more preferably 30 mol% or less, and may also be 25 mol% or less or 20 mol% or less.

[0075] Other monomer-derived structural units include structural unit (b) derived from an aromatic compound having one vinyl group (monovinyl aromatic compound).

[0076] The constituent unit (b) derived from the monovinyl aromatic compound is preferably a constituent unit represented by the following formula (V4).

[0077] In formula (V4), L ２ is an aromatic hydrocarbon linking group, and a specific example of a preferred one is the above L １ Examples include the following. * indicates the bonding position. R Ｖ１ R is a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms (preferably an alkyl group). Ｖ１ When it is a hydrocarbon group, the number of carbon atoms is preferably 1 to 6, and more preferably 1 to 3. Ｖ１ and L ２ It may have the substituent Z described above.

[0078] When a polymer having a structural unit represented by formula (V) is a copolymer containing structural unit (b) derived from a monovinyl aromatic compound, examples of monovinyl aromatic compounds include vinyl aromatic compounds such as styrene, vinylnaphthalene, and vinylbiphenyl; and nuclear alkyl-substituted vinyl aromatic compounds such as o-methylstyrene, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, o-ethylvinylbenzene, m-ethylvinylbenzene, p-ethylvinylbenzene, methylvinylbiphenyl, and ethylvinylbiphenyl. The monovinyl aromatic compounds exemplified here may optionally have the above-mentioned substituent Z. Furthermore, one or more of these monovinyl aromatic compounds may be used. Among these, structural unit (b) preferably contains structural units derived from at least one selected from the group consisting of o-ethylvinylbenzene, m-ethylvinylbenzene, and p-ethylvinylbenzene, and more preferably further contains structural units derived from styrene in addition to structural units derived from at least one selected from the group consisting of o-ethylvinylbenzene, m-ethylvinylbenzene, and p-ethylvinylbenzene.

[0079] When a polymer having a structural unit represented by formula (V) is a copolymer containing structural unit (b), the copolymerization ratio of structural unit (b) is preferably 10 mol% or more, more preferably 15 mol% or more, and may be 20 mol% or more, 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, or 75 mol% or more. The upper limit is preferably 98 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less.

[0080] A polymer having a structural unit represented by formula (V) may have other structural units besides structural units (a) and (b). Examples of other structural units include structural unit (c) derived from a cycloolefin compound. Examples of cycloolefin compounds include hydrocarbons having a double bond in the ring structure. Specifically, examples include monocyclic cyclic olefins such as cyclobutene, cyclopentene, cyclohexene, and cyclooctene, as well as compounds having a norbornene ring structure such as norbornene and dicyclopentadiene, and cycloolefin compounds in which aromatic rings are fused, such as indene and acenaphthylene. Examples of norbornene compounds are those described in paragraphs 0037 to 0043 of Japanese Patent Application Publication No. 2018-039995, the contents of which are incorporated herein by reference. The cycloolefin compounds exemplified herein may further have the substituent Z described above.

[0081] When a polymer having a structural unit represented by formula (V) is a copolymer containing structural unit (c), the copolymerization ratio of structural unit (c) is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 30 mol% or more. The upper limit is preferably 90 mol% or less, more preferably 80 mol% or less, even more preferably 70 mol% or less, and may also be 50 mol% or less, or 30 mol% or less.

[0082] A polymer having a structural unit represented by formula (V) may also incorporate structural unit (d) derived from a different polymerizable compound (hereinafter also referred to as "other polymerizable compound"). Examples of other polymerizable compounds (monomers) include compounds containing three vinyl groups. Specifically, examples include 1,3,5-trivinylbenzene, 1,3,5-trivinylnaphthalene, and 1,2,4-trivinylcyclohexane. Alternatively, examples include ethylene glycol diacrylate, butadiene (e.g., 1,3-butadiene), isoprene, etc. The copolymerization ratio of structural unit (d) derived from the other polymerizable compound is preferably 30 mol% or less, more preferably 20 mol% or less, and even more preferably 10 mol% or less.

[0083] As one embodiment of a polymer having a structural unit represented by formula (V), a polymer is provided in which structural unit (a) is essential and at least one of structural units (b) and (c) is included. Furthermore, an embodiment is provided in which the sum of structural units (a) to (c) accounts for 90 mol% or more, more preferably 95 mol% or more, and particularly preferably 98 mol% or more of the total structural units. As another embodiment of a polymer having a structural unit represented by formula (V), a polymer is provided in which structural unit (a) is essential and at least one of structural units (b) to (d) is included. Furthermore, an embodiment is provided in which the sum of structural units (a) to (d) accounts for 95 mol% or more, more preferably 98 mol% or more of the total structural units. As yet another embodiment of a polymer having a structural unit represented by formula (V), structural unit (a) is essential, and it is preferable that the polymer contains 90 mol% or more of structural units including aromatic rings among all structural units excluding the terminals, more preferably 95 mol% or more, and may also be a polymer of 100 mol%. In calculating the mole percentage per total constituent unit, one constituent unit is defined as one molecule of the monomer (e.g., divinyl aromatic compound, monovinyl aromatic compound, etc.) used in the production of a polymer having a constituent unit represented by formula (V).

[0084] The method for producing a polymer having a constituent unit represented by formula (V) is not particularly limited and can be carried out by conventional methods. For example, a raw material containing a divinyl aromatic compound (and, if necessary, a monovinyl aromatic compound, a cycloolefin compound, etc.) can be polymerized in the presence of a Lewis acid catalyst. As the Lewis acid catalyst, a metal fluoride such as boron trifluoride or a complex thereof can be used.

[0085] The structure of the chain ends of a polymer having a constituent unit represented by formula (V) is not particularly limited, but with respect to the group derived from the above-mentioned divinyl aromatic compound, it can take the structure of formula (E1) below. Note that L in formula (E1) １ This is the same as defined in formula (V1) above. * indicates the bond position. *-CH=CH-L １ -CH=CH ２ (E1)

[0086] When a group derived from a monovinyl aromatic compound becomes the chain terminus, it can take the structure shown in formula (E2) below. ２ and R Ｖ１ These have the same meaning as defined in equation (V4) above. * represents the bond position. *-CH=CH-L ２ -R Ｖ１ (E2)

[0087] The molecular weight of the polymer having the constituent unit represented by formula (V) is preferably 300 or more, more preferably 500 or more, even more preferably 1,000 or more, and even more preferably 1,500 or more, in terms of number average molecular weight (Mn). The upper limit of the number average molecular weight is preferably 130,000 or less, more preferably 120,000 or less, even more preferably 110,000 or less, even more preferably 100,000 or less, and may also be 30,000 or less, 10,000 or less, or 5,000 or less. The molecular weight of the polymer having the constituent unit represented by formula (V) is preferably 3,000 or more, more preferably 5,000 or more, and even more preferably 10,000 or more, in terms of weight average molecular weight Mw. By setting the weight average molecular weight to be above the lower limit, the excellent low dielectric properties (Dk and / or Df), particularly Df and dielectric properties after moisture absorption, of the polymer having the constituent unit represented by formula (V) can be effectively exhibited in the cured product of the resin composition. The upper limit of the weight-average molecular weight Mw is preferably 130,000 or less, more preferably 100,000 or less, even more preferably 80,000 or less, and even more preferably 50,000 or less. By keeping the weight-average molecular weight below the above upper limit, when the resin film or the like is laminated onto a circuit forming substrate, embedding defects tend to be less likely to occur. The monodispersity (Mw / Mn), expressed as the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), is preferably 100 or less, more preferably 50 or less, even more preferably 20 or less, and may also be 15 or less or 12 or less. As a lower limit, it is practical to be 1.1 or more, preferably 2.0 or more, more preferably 4 or more, even more preferably 5 or more, even more preferably 7 or more, and even more preferably 8 or more. When the resin composition in this embodiment contains two or more polymers having a constituent unit represented by formula (V), it is preferable that the Mw, Mn, and Mw / Mn of the mixture satisfy the above ranges.

[0088] The equivalent amount of vinyl groups in a polymer having a constituent unit represented by formula (V) is preferably 200 g / eq. or more, more preferably 230 g / eq. or more, even more preferably 250 g / eq. or more, and may be 300 g / eq. or more, or 350 g / eq. or more. Furthermore, the equivalent amount of vinyl groups is preferably 1200 g / eq. or less, more preferably 1000 g / eq. or less, and may be 800 g / eq. or less, 600 g / eq. or less, 500 g / eq. or less, 400 g / eq. or less, or 350 g / eq. or less. When the equivalent amount of vinyl groups is above the lower limit, the storage stability of the resin composition tends to improve, and the fluidity of the resin composition tends to improve. As a result, moldability improves, and a more reliable printed circuit board tends to be obtained. On the other hand, when the equivalent amount of vinyl groups is below the upper limit, the heat resistance of the resulting cured product tends to improve.

[0089] Polymers having a constituent unit represented by formula (V) preferably have cured products with excellent low dielectric properties (Dk and / or Df). For example, the cured product of a polymer having a constituent unit represented by formula (V) used in this embodiment preferably has a relative permittivity (Dk) at 10 GHz measured according to the cavity resonator perturbation method of 2.80 or less, more preferably 2.60 or less, even more preferably 2.50 or less, and even more preferably 2.40 or less. Furthermore, a practical lower limit for the relative permittivity is, for example, 1.80 or more. Furthermore, the cured product of a polymer having a constituent unit represented by formula (V) preferably has a dielectric loss tangent (Df) at 10 GHz measured according to the cavity resonator perturbation method of 0.0030 or less, more preferably 0.0020 or less, and even more preferably 0.0010 or less. Furthermore, a practical lower limit for the dielectric loss tangent is, for example, 0.0001 or more. The relative permittivity (Dk) and dielectric loss tangent (Df) are measured by the following method. 4.5 g of resin powder is spread into a stainless steel mold measuring 100 mm x 30 mm x 1.0 mm high, and placed in a vacuum press (manufactured by Kitagawa Seiki Co., Ltd.). The mold is held at 200°C for 2 hours and pressed at a surface pressure of 3.0 MPa to produce a cured plate. After downsizing the cured plate to a width of 1.0 mm, it is dried at 120°C for 60 minutes. The relative permittivity (Dk) and dielectric loss tangent (Df) after drying are then measured at 10 GHz using a perturbation cavity resonator. The measurement temperature is 23°C.

[0090] With respect to polymers having a constituent unit represented by formula (V) in this specification, reference can be made to and incorporated herein to the compounds and their synthesis reaction conditions described in paragraphs 0029 to 0058 of International Publication No. 2017 / 115813, the compounds and their synthesis reaction conditions described in paragraphs 0013 to 0058 of Japanese Patent Application Publication No. 2018-039995, the compounds and their synthesis reaction conditions described in paragraphs 0008 to 0043 of Japanese Patent Application Publication No. 2018-168347, the compounds and their synthesis reaction conditions described in paragraphs 0014 to 0042 of Japanese Patent Application Publication No. 2006-070136, the compounds and their synthesis reaction conditions described in paragraphs 0014 to 0061 of Japanese Patent Application Publication No. 2006-089683, and the compounds and their synthesis reaction conditions described in paragraphs 0008 to 0036 of Japanese Patent Application Publication No. 2008-248001. A polymer having the constituent unit represented by formula (V) can be a commercially available product, such as LF-310T50 manufactured by Nippon Steel Chemical & Material Co., Ltd.

[0091] In this embodiment, if the resin composition contains a polymer having a structural unit represented by formula (V), the lower limit of its content is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and depending on the application, it may be 15 parts by mass or more, 20 parts by mass or more, or 25 parts by mass or more. By setting the content of the polymer having a structural unit represented by formula (V) to the above lower limit, it tends to be possible to effectively achieve low dielectric properties, in particular, a low relative permittivity. Furthermore, the upper limit of the content of the polymer having a structural unit represented by formula (V) is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, even more preferably 60 parts by mass or less, and may be 50 parts by mass or less, 45 parts by mass or less, 40 parts by mass or less, 35 parts by mass or less, or 30 parts by mass or less, based on 100 parts by mass of resin solids in the resin composition. By keeping the content of polymers having the structural unit represented by formula (V) below the above upper limit, the metal foil peel strength and low water absorption tend to improve. The resin composition in this embodiment may contain only one type of polymer having the structural unit represented by formula (V), or it may contain two or more types. When two or more types are included, it is preferable that the total amount is within the above range. Furthermore, the resin composition in this embodiment may also be configured to substantially not contain polymers having the structural unit represented by formula (V). Substantially not containing polymers means that the content of polymers having the structural unit represented by formula (V) is less than 1 part by mass per 100 parts by mass of resin solids in the resin composition, preferably less than 0.1 parts by mass, and more preferably less than 0.01 parts by mass.

[0092] << (In formula (T1), Mb represents a hydrocarbon group having 1 to 12 carbon atoms, which may each be independently substituted with a halogen atom, and y represents an integer from 0 to 4. * represents the bond position with other sites.) For details of the aromatic resin having a carbon-carbon double bond at its terminus, which has a terminus represented by formula (T1) and an indan skeleton, please refer to paragraphs 0012 to 0033 of Japanese Patent Application Publication No. 2024-081683, which are incorporated herein by reference.

[0093] In this embodiment, if the resin composition contains a resin having an end group represented by formula (T1) and an indan skeleton, the lower limit of its content is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and depending on the application, it may be 15 parts by mass or more, 20 parts by mass or more, or 25 parts by mass or more. By setting the content of the resin having an end group represented by formula (T1) and an indan skeleton to the above lower limit or higher, low dielectric properties, in particular low relative permittivity, tend to be effectively achieved. Furthermore, the upper limit of the content of the resin having an end group represented by formula (T1) and an indan skeleton is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, even more preferably 60 parts by mass or less, and may be 50 parts by mass or less, 45 parts by mass or less, 40 parts by mass or less, 35 parts by mass or less, or 30 parts by mass or less, based on 100 parts by mass of resin solids in the resin composition. By keeping the content of the resin having an end group represented by formula (T1) and an indan skeleton below the above upper limit, the metal foil peel strength and low water absorption tend to improve. The resin composition in this embodiment may contain only one type of resin having an end group represented by formula (T1) and an indan skeleton, or it may contain two or more types. When two or more types are included, it is preferable that the total amount is within the above range. Furthermore, the resin composition in this embodiment may also be configured to substantially not contain the resin having an end group represented by formula (T1) and an indan skeleton. Substantially not containing means that the content of the resin having an end group represented by formula (T1) and an indan skeleton is less than 1 part by mass per 100 parts by mass of resin solids in the resin composition, preferably less than 0.1 parts by mass, and more preferably less than 0.01 parts by mass.

[0094] <<Cyanate Ester Compounds>> The resin composition in this embodiment may contain cyanate ester compounds. The cyanate ester compound in this embodiment is not particularly limited as long as it contains one or more cyanate groups (preferably two or more, more preferably two to twelve, even more preferably two to six, even more preferably two to four, even more preferably two or three, and even more preferably two) in one molecule, and compounds commonly used in the field of printed circuit boards can be widely used. Furthermore, it is preferable that the cyanate ester compound is a compound in which the cyanate group is directly bonded to an aromatic skeleton (aromatic ring). Preferred cyanate ester compounds in this embodiment include, for example, at least one selected from the group consisting of phenol novolac type cyanate ester compounds, naphthol aralkyl type cyanate ester compounds (naphthol aralkyl type cyanates), naphthylene ether type cyanate ester compounds, biphenyl aralkyl type cyanate ester compounds, xylene resin type cyanate ester compounds, trisphenolmethane type cyanate ester compounds, adamantane skeleton type cyanate ester compounds, bisphenol M type cyanate ester compounds, bisphenol A type cyanate ester compounds, bisphenol E type cyanate ester compounds, diallylbisphenol A type cyanate ester compounds, and indancyanate compounds. Among these, from the viewpoint of further improving the low water absorption of the resulting cured product, it is more preferable to use at least one selected from the group consisting of phenol novolac type cyanate ester compounds, naphthol aralkyl type cyanate ester compounds, naphthylene ether type cyanate ester compounds, xylene resin type cyanate ester compounds, bisphenol M type cyanate ester compounds, bisphenol A type cyanate ester compounds, and diallylbisphenol A type cyanate ester compounds; it is even more preferable to use at least one selected from the group consisting of phenol novolac type cyanate ester compounds and naphthol aralkyl type cyanate ester compounds; and it is even more preferable to use a naphthol aralkyl type cyanate ester compound.These cyanate ester compounds may be prepared by known methods or commercially available products may be used. Cyanate ester compounds having a naphthol aralkyl skeleton, naphthylene ether skeleton, xylene skeleton, trisphenolmethane skeleton, or adamantane skeleton tend to have a relatively large number of functional group equivalents and fewer unreacted cyanate ester groups, resulting in cured resin compositions using these compounds exhibiting even greater low water absorption. Furthermore, due primarily to the presence of an aromatic or adamantane skeleton, plating adhesion tends to be even more improved.

[0095] As naphthol aralkyl type cyanate ester compounds, compounds represented by the following formula (1) are more preferred. (In formula (1), R ３ Each of these independently represents either a hydrogen atom or a methyl group, and n3 represents an integer greater than or equal to 1.

[0096] In formula (1), R ３ Each of these independently represents either a hydrogen atom or a methyl group, with hydrogen atoms being preferred. In formula (1), n3 is an integer of 1 or more, preferably an integer between 1 and 20, more preferably an integer between 1 and 10, and even more preferably an integer between 1 and 6.

[0097] Furthermore, while the novolac-type cyanate ester compound is not particularly limited, for example, a compound represented by the following formula (VII) is preferred. (In formula (VII), R ６ Each of these independently represents either a hydrogen atom or a methyl group, and n7 represents an integer greater than or equal to 1.

[0098] In formula (VII), R ６ Each of these independently represents either a hydrogen atom or a methyl group, with hydrogen atoms being preferred. In formula (VII), n7 is an integer of 1 or more, preferably an integer between 1 and 20, more preferably an integer between 1 and 10, and even more preferably an integer between 1 and 6.

[0099] As the bisphenol A type cyanate ester compound, one or more compounds selected from the group consisting of 2,2-bis(4-cyanatophenyl)propane and 2,2-bis(4-cyanatophenyl)propane prepolymers may be used.

[0100] Examples of indanthyanate compounds include those represented by the following formula (a): Formula (a) (In equation (a), n is the average number of repetitions, and is a number between 3.0 and 15.0.)

[0101] In addition to the above, other cyanate ester compounds can also be used, including those described in paragraphs 0035 to 0061 of Japanese Patent Application No. 2024-110099, which are incorporated herein by reference.

[0102] The resin composition in this embodiment preferably contains a cyanate ester compound in a range that does not impair the effects of the present invention. When the resin composition in this embodiment contains a cyanate ester compound, the lower limit of its content is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of resin solids in the resin composition. When the cyanate ester compound content is 0.1 parts by mass or more, the heat resistance, flame resistance, chemical resistance, low dielectric properties (low relative permittivity, low dielectric loss tangent), and insulation properties of the resulting cured product tend to improve. The resin composition in this embodiment may contain only one type of cyanate ester compound, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0103] <<(meth)allyl compounds, (meth)acrylate compounds, epoxy compounds, phenol compounds, oxetane compounds, benzoxazine compounds, arylcyclobutene compounds, perfluorovinyl ether resins, polyimide compounds, and compounds having a vinylene group>> The resin composition of this embodiment may contain at least one of (meth)allyl compounds, (meth)acrylate compounds, epoxy compounds, phenol compounds, oxetane compounds, benzoxazine compounds, arylcyclobutene compounds, perfluorovinyl ether resins, polyimide compounds, and compounds having a vinylene group. Details of these compounds can be found in paragraphs 0121 to 0159 of Japanese Patent Application Publication No. 2024-081683 and paragraphs 0173 to 0225 of International Publication No. 2024 / 101238, the contents of which are incorporated herein by reference.

[0104] In the resin composition of this embodiment, the content of (meth)allyl compounds, (meth)acrylate compounds, epoxy compounds, phenol compounds, oxetane compounds, benzoxazine compounds, arylcyclobutene compounds, perfluorovinyl ether resins, polyimide compounds, and compounds having vinylene groups is, independently, 0 parts by mass or more, 1 part by mass or more, 10 parts by mass or more, preferably 90 parts by mass or less, more preferably 50 parts by mass, 10 parts by mass or less, 5 parts by mass or less, 1 part by mass or less, and depending on the application, it may be 0.1 parts by mass or less, or 0.01 parts by mass or less.

[0105] <Thermoplastic Elastomer> The resin composition of this embodiment includes an elastomer (hereinafter sometimes referred to as "thermoplastic elastomer (A)") in which a dumbbell-shaped No. 6 test piece with a thickness of 0.1 mm, molded at 200°C and 3 MPa, has an elongation of 200% or more at break measured at a tensile speed of 5 mm / min in accordance with JIS K 6251, and the elongation of the test piece after heating at 150°C for 3 hours is also 200% or more. By using thermoplastic elastomer (A), the resulting cured product can be given flexibility that is less susceptible to deterioration by heating.

[0106] The elongation at break of thermoplastic elastomer (A) before heating is 200% or more, preferably 250% or more, more preferably 300% or more, even more preferably 350% or more, and usually 1000% or less, but may be 800% or less, or 700% or less. Setting it above the lower limit tends to improve toughness and crack resistance after high-temperature / cold-temperature cycling tests. Setting it below the upper limit tends to make it easier to mix with thermosetting resins and improve heat resistance. The elongation at break of thermoplastic elastomer (A) after heating is 200% or more, preferably 250% or more, more preferably 300% or more, even more preferably 350% or more, even more preferably 400% or more, and even more preferably 450% or more, and usually 1000% or less, but may be 800% or less, or 700% or less. By setting the value above the lower limit, oxidative degradation under high-temperature conditions becomes less likely, and crack resistance after high-temperature / cold-temperature cycling tests tends to improve. Conversely, by setting the value below the upper limit, mixing with thermosetting resins becomes easier, and heat resistance tends to improve. For thermoplastic elastomer (A), it is preferable that the elongation at break after heating is greater than the elongation at break before heating. Specifically, it is preferable that the elongation at break after heating minus the elongation at break before heating is 10% or more, more preferably 50% or more, and preferably 200% or less.

[0107] A thermoplastic elastomer (A) that satisfies the above-mentioned elongation rate at fracture before and after heating can be obtained, for example, by adjusting it to satisfy two, three, or all of the following conditions: (1) The thermoplastic elastomer (A) is a block copolymer having a styrene skeleton; (2) The proportion of units having a styrene skeleton in the thermoplastic elastomer (A) is 10 to 67% by mass; (3) The thermoplastic elastomer (A) is hydrogenated; (4) The thermoplastic elastomer (A) contains units having a styrene skeleton with methyl groups. Details of these requirements will be explained below.

[0108] Thermoplastic elastomer A is preferably a block copolymer having a styrene skeleton. Elastomer A contains units having a styrene skeleton. The units having a styrene skeleton are monomer units derived from styrene and / or styrene derivatives, and are preferably units having a styrene skeleton having a methyl group and / or an ethyl group, and more preferably units having a styrene skeleton having a methyl group. Specifically, the units having a styrene skeleton are preferably at least one selected from the group consisting of o-methylstyrene units, p-methylstyrene units, o-ethylstyrene units, p-ethylstyrene units, o-isopropylstyrene units, p-isopropylstyrene units, o-methyl-α-methylstyrene units, p-methyl-α-methylstyrene units, o-ethyl-α-methylstyrene units, p-ethyl-α-methylstyrene units, o-isopropyl-α-methylstyrene units, and p-isopropyl-α-methylstyrene units, and more preferably include p-methylstyrene units. When radicals are generated during curing, units having a styrene skeleton with a methyl group and / or an ethyl group are more easily incorporated into the crosslinked structure of the thermosetting resin. When a thermoplastic elastomer (A) is incorporated into the crosslinked structure of a thermosetting resin, its effect in imparting toughness as an elastomer tends to decrease. In this embodiment, it is presumed that by curing in the absence of a radical polymerization initiator, a cured product can be obtained in which crack formation after temperature cycling tests is effectively suppressed, even when using a thermoplastic elastomer containing units having a styrene skeleton with methyl and / or ethyl groups.

[0109] The proportion of units having a styrene skeleton (preferably methylstyrene units) in the thermoplastic elastomer (A) is preferably 10% by mass, more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 35% by mass or more, and may also be 40% by mass or more. Alternatively, it may be 67% by mass or less, more preferably 60% by mass or less, even more preferably 55% by mass or less, even more preferably 50% by mass or less, and may also be 45% by mass or less. Setting it below the above upper limit tends to increase the elongation at break. Setting it above the above lower limit tends to allow for effective dispersion in the thermosetting resin containing the maleimide compound.

[0110] In thermoplastic elastomer (A), if the proportion of units having a styrene skeleton is low, it tends to be difficult to mix with thermosetting resins containing maleimide compounds. Therefore, when blending thermoplastic elastomers with thermosetting resins, there is a tendency to select elastomers with a high proportion of styrene units, i.e., elastomers with a high styreneization rate. In this embodiment, by using an elastomer containing units having a styrene skeleton with methyl groups as the units having a styrene skeleton, it is possible to improve the mixability with thermosetting resins even with a low styreneization rate. Furthermore, in this embodiment, it is preferable to use a thermosetting resin with low dielectric properties. By using such a low dielectric thermosetting resin, the dispersibility of thermoplastic elastomer (A) can be further improved.

[0111] The thermoplastic elastomer (A) used in this embodiment is preferably hydrogenated. Hydrogenation may be partial or complete, but complete hydrogenation is more preferable. Complete hydrogenation here means that 95% or more of the double bonds in the thermoplastic elastomer (A) are hydrogenated, and it is not necessarily required that 100% be hydrogenated. Hydrogenated thermoplastic elastomers are less susceptible to oxidative degradation under high-temperature conditions, and the occurrence of cracks when the resulting cured product is exposed to high-temperature conditions can be more effectively suppressed.

[0112] In other words, the elastomer used in this embodiment preferably includes blocks containing a styrene skeleton, blocks containing conjugated diene compound units, and blocks containing both a styrene skeleton and conjugated diene compound units, and it is preferable that some or all of these conjugated diene blocks are hydrogenated. In this embodiment, complete hydrogenation is preferred.

[0113] The conjugated diene compound unit preferably contains at least one selected from the group consisting of butadiene units, isoprene units, 2,3-dimethyl-1,3-butadiene units, 1-phenyl-1,3-butadiene units, 1,3-pentadiene units, 1,3-hexadiene units, 3-butyl-1,3-octadiene units, farnesene units, myrcene units, piperylene units, and cyclohexadiene units, more preferably contains butadiene units and / or isoprene units, and even more preferably contains at least butadiene units.

[0114] In this embodiment, it is more preferable that the conjugated diene compound unit includes a hydrogenated or partially hydrogenated butadiene unit and / or a hydrogenated or partially hydrogenated isoprene unit. The conjugated diene unit is preferably a 1,3-butadiene unit, and more preferably a constituent unit in which the 1,3-butadiene unit is hydrogenated or partially hydrogenated. Typically, a hydrogenated butadiene unit includes a butylene unit and / or an ethylene unit. Also, a hydrogenated isoprene unit includes an ethylene unit and a propylene unit. In this embodiment, it is preferable that the conjugated diene compound unit includes a butylene unit and / or an ethylene unit. Including a butylene unit and / or an ethylene unit tends to further improve low dielectric properties and flexibility.

[0115] The thermoplastic elastomer (A) used in this embodiment is a hydrogenated SEBS elastomer (a copolymer of a styrene unit block, a block composed of a hydrogenated or partially hydrogenated butadiene unit block, and an ethylene unit block), and the styrene unit block is preferably an elastomer containing a methylstyrene unit block.

[0116] The thermoplastic elastomer (A) preferably has a total of methylstyrene units and conjugated diene units of 90% by mass or more, more preferably 95% by mass or more, even more preferably 97% by mass or more, even more preferably 99% by mass or more, and also 100% by mass or less.

[0117] The thermoplastic elastomer (A) of this embodiment can be manufactured by the method described in paragraphs 0038 to 0045 and 0104 to 0107 of Japanese Patent Application Publication No. 2022-33057. As such a commercially available product, for example, Kraton's MD3501 can be used.

[0118] The content of thermoplastic elastomer (A) in the resin composition of this embodiment is preferably 5 to 35 parts by mass per 100 parts by mass of resin solids in the resin composition. Furthermore, the content of thermoplastic elastomer (A) is preferably 7 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, even more preferably 18 parts by mass or more, preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 22 parts by mass or less, per 100 parts by mass of resin solids in the resin composition. By setting the content of thermoplastic elastomer (A) above the lower limit, the low dielectric properties and low thermal expansion properties of the resulting cured product tend to be further improved. Also, by setting the content of thermoplastic elastomer (A) below the upper limit, the heat resistance of the resulting cured product tends to be further improved. The resin composition of this embodiment may contain only one type of thermoplastic elastomer (A), or it may contain two or more types. When two or more types are included, it is preferable that the total amount is within the above range.

[0119] <Other elastomers besides thermoplastic elastomer (A)> The resin composition of this embodiment may also contain other elastomers besides thermoplastic elastomer (A). The elastomers other than thermoplastic elastomer (A) are elastomers in which the elongation at break of a 0.1 mm thick dumbbell-shaped No. 6 test piece, molded at 200°C and 3 MPa, measured at a tensile speed of 5 mm / min in accordance with JIS K 6251, is less than 200%, or the elongation after heating the test piece at 150°C for 3 hours is less than 200%.

[0120] As an elastomer other than thermoplastic elastomer (A), it is preferable to use thermoplastic elastomer (A1) containing unhydrogenated conjugated diene compound units (hereinafter sometimes simply referred to as "thermoplastic elastomer (A1)"). By using thermoplastic elastomer (A1), dispersibility in thermosetting resin can be further improved. In addition, the compatibility of each component is improved, and the occurrence of blistering of the cured product during reflow tends to be more effectively suppressed. It is more preferable that thermoplastic elastomer (A1) is an elastomer containing blocks having a styrene skeleton and blocks containing blocks containing unhydrogenated conjugated diene compound units. Furthermore, it is preferable that thermoplastic elastomer (A1) is a styrene-based elastomer in which the styrene units preferably do not have methyl groups, more preferably radical-reactive groups.

[0121] In thermoplastic elastomer (A1), the proportion of unhydrogenated conjugated diene compound units is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 50% by mass or less, and more preferably 40% by mass or less, based on 100% by mass of the elastomer. Setting the proportion above the lower limit improves compatibility with thermosetting resins and tends to further improve heat resistance.

[0122] Other elastomers besides thermoplastic elastomer (A) are preferred, and among thermoplastic elastomers other than thermoplastic elastomer (A1), hydrogenated styrene-based elastomers are preferred, which have methyl groups, more preferably radical-reactive groups, in the styrene units. Specifically, hydrogenated SEPS elastomers, which have methyl groups, more preferably radical-reactive groups, in the styrene units, are given as examples. In addition to the above, other elastomers besides thermoplastic elastomer (A) can be found in paragraphs 0043 to 0054 of International Publication No. 2024 / 225152, which are incorporated herein by reference.

[0123] In the resin composition of this embodiment, the mass ratio of thermoplastic elastomer (A) to thermoplastic elastomer other than thermoplastic elastomer (A) (preferably thermoplastic elastomer (A1)) is such that, when the total of thermoplastic elastomer (A) and thermoplastic elastomer (A1) is 100 parts by mass, the proportion of thermoplastic elastomer (A1) is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 25 parts by mass or more, even more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less. Setting the ratio above the lower limit improves the compatibility between thermoplastic elastomer (A) and other thermosetting resins, and tends to more effectively suppress swelling after reflow. Furthermore, setting the ratio below the upper limit tends to suppress thermal degradation and maintain high toughness even after crack testing, thereby more effectively suppressing cracks in the resin. The resin composition of this embodiment may contain only one thermoplastic elastomer (A) and one other thermoplastic elastomer (preferably thermoplastic elastomer (A1)), or it may contain two or more. When it contains two or more, it is preferable that the total amount is within the above range.

[0124] In an example of the resin composition of this embodiment, it is preferable that the total of thermoplastic elastomer (A) and thermoplastic elastomer (A1), which may be added as needed, accounts for 70% by mass or more of the total thermoplastic elastomer contained in the resin composition, more preferably 75% by mass or more, even more preferably 80% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0125] <Radical Polymerization Initiator> The resin composition of this embodiment does not contain a radical polymerization initiator. By not containing a radical polymerization initiator, radicals are less likely to be generated during the curing of the resin composition, and low dielectric properties can be effectively maintained. Furthermore, even if the thermoplastic elastomer used in this embodiment has radical-reactive groups, the thermoplastic elastomer is less likely to be incorporated into the crosslinking structure of thermosetting resins such as maleimide compounds. As a result, the thermoplastic elastomer can effectively exhibit its inherent functions. The absence of a radical polymerization initiator also suppresses deterioration of electrical properties. In addition, by not containing a photo-radical polymerization initiator, photocuring of the thermosetting resin can be effectively suppressed even without light shielding during storage. The resin composition of this embodiment does not contain a radical polymerization initiator, but "does not contain" here means that it is not actively included, and does not mean that impurities, etc., are included unintentionally. Unintentional inclusion of impurities, etc., refers to, for example, 4 ppm or less by mass, and moreover, 1 ppm or less. In this embodiment, 0 ppm is preferable. The type of radical polymerization initiator is not particularly limited, and examples include thermal radical polymerization initiators and photoradical polymerization initiators. Specific examples of radical polymerization initiators include peroxides, azo compounds, benzoin compounds, acetophenone compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, and phosphine oxide compounds. Peroxides include compounds having a peroxy group (-O-O-) in the molecule, with compounds having a t-butyl peroxy group, a cumyl peroxy group, or a benzoyl peroxy group being preferred. Specific examples include benzoyl peroxide (BPO), p-chlorobenzoyl peroxide, dicumyl peroxide (dicup), di-t-butyl peroxide, diisopropyl peroxycarbonate, 2,5-dimethyl-2,5-di-t-butylperoxyhexine (DYBP), and 2,5-dimethyl-2,5-di-t-butylperoxyhexane.Commercially available products include Perbutyl H, Perbutyl P, Perbutyl PV, Permil H, Permil P, Permil D, Perocta H, and Perhexa 25B, all manufactured by NOF Corporation. Azo compounds refer to compounds having an azo group (-N=N-) in the molecule, and specifically include azobisisobutyronitrile (AIBN). Commercially available products include AIBN, V-70, and V-65, manufactured by Fujifilm Wako Pure Chemical Industries. Although not a peroxide, 2,3-dimethyl-2,3-diphenylbutane can also be used as a radical polymerization initiator. A commercially available product is Nofmer BC-90. Furthermore, radical polymerization initiators described in paragraph 0042 of International Publication No. 2013 / 047305 are also exemplified, and these contents are incorporated herein. On the other hand, the resin composition according to this embodiment may also have a configuration that does not include a cationic polymerization initiator. Furthermore, the resin composition according to this embodiment may also have a configuration that does not include a photopolymerization initiator.

[0126] <Flame Retardant> The resin composition of this embodiment may contain a flame retardant. Examples of flame retardants include phosphorus-based flame retardants, halogen-based flame retardants, inorganic flame retardants, and silicone-based flame retardants, with phosphorus-based flame retardants being preferred. Known flame retardants can be used, for example, brominated epoxy resin, brominated polycarbonate, brominated polystyrene, brominated styrene, brominated phthalimide, tetrabromobisphenol A, pentabromobenzyl (meth)acrylate, pentabromotoluene, tribromophenol, hexabromobenzene, decabromodiphenyl ether, bis-1,2-pentabromopenyleethane, chlorinated polystyrene, halogen-based flame retardants such as chlorinated paraffin, red phosphorus, tricresyl phosphate, triphenyl phosphate, cresyldiphenyl phosphate, trixylenyl phosphate, trialkyl phosphate, dialkyl phosphate. Examples of phosphorus-based flame retardants include tris(chloroethyl) phosphate, phosphazene, 1,3-phenylenebis(2,6-dixylenyl phosphate), 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, tris(2,6-diisopropyl-4-vinylphenyl) phosphate, tris(2,6-di-t-butyl-4-vinylphenyl) phosphate, phosphorus-based flame retardants such as phosphorus-based flame retardants Group A shown below, inorganic flame retardants such as aluminum hydroxide, magnesium hydroxide, partial boehmite, boehmite, zinc borate, antimony trioxide, and silicone-based flame retardants such as silicone rubber and silicone resin. <Phosphorus-based flame retardants Group A>

[0127] When the resin composition of this embodiment contains a flame retardant, its content is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and even more preferably 7 parts by mass or more, per 100 parts by mass of resin solids in the resin composition. Setting the content above the lower limit tends to more effectively exhibit the flame retardancy of the resulting cured product. Furthermore, the lower limit of the flame retardant content is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, per 100 parts by mass of resin solids in the resin composition. Setting the content below the upper limit tends to more effectively suppress the deterioration of other physical properties. The flame retardant can be used alone or in combination of two or more types. When two or more types are used, the total amount will be within the above range.

[0128] <Activated Ester Compounds> The resin composition of this embodiment may contain activated ester compounds to the extent that they do not impair the effects of the present invention. The activated ester compounds are not particularly limited, and for example, the description in paragraphs 0064 to 0066 of International Publication No. 2021 / 172317 can be referenced, and this content is incorporated herein.

[0129] When the resin composition of this embodiment contains an active ester compound, it is preferable that the amount is 1 part by mass or more, and more preferably 50 parts by mass or less, per 100 parts by mass of resin solids in the resin composition. The resin composition of this embodiment may contain only one type of active ester compound, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range. Furthermore, the resin composition of this embodiment may also be configured to be substantially free of active ester compounds. Substantially free means that the content of the active ester compound is less than 1 part by mass, preferably less than 0.1 parts by mass, and more preferably less than 0.01 parts by mass, per 100 parts by mass of resin solids in the resin composition.

[0130] <Aromatic Vinyl Compounds and Aromatic Oligomers> The resin composition of this embodiment may contain aromatic vinyl compounds and / or aromatic oligomers, and more preferably contains aromatic vinyl compounds. Examples of aromatic vinyl compounds include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 2,4,6-trimethylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, vinylanthracene, N,N-diethyl-4-aminoethylstyrene, vinylpyridine, 4-methoxystyrene, monochlorostyrene, dichlorostyrene, orthodivinylbenzene, metadivinylbenzene, paradivinylbenzene, and the like. These aromatic vinyl compounds may be used individually or in combination of two or more. Among these, styrene, α-methylstyrene, 4-methylstyrene, orthodivinylbenzene, metadivinylbenzene, and paradivinylbenzene are preferred, with 4-methylstyrene and orthodivinylbenzene being more preferred.

[0131] Aromatic oligomers are oligomers having structural units derived from aromatic vinyl compounds, and typically refer to compounds with a weight-average molecular weight of less than 3000. Aromatic oligomers are also typically thermoplastic oligomers. In this embodiment, aromatic oligomers do not include polymers having structural units represented by formula (V), styrene elastomers, or any of the compounds explicitly mentioned in any of the above sections.

[0132] Aromatic oligomers may contain constituent units derived from monomers other than aromatic vinyl compounds. Examples of such other monomers include (meth)acrylic acid, (meth)acrylic acid derivatives, (meth)acrylamide, (meth)acrylamide derivatives, (meth)acrylonitrile, isoprene, 1,3-butadiene, ethylene, vinyl acetate, vinyl chloride, vinylidene chloride, N-vinylindole, N-vinylphthalimide, N-vinylpyrrolidone, N-vinylcarbazole, and N-vinylcaprolactam.

[0133] The content of constituent units derived from aromatic vinyl compounds in the aromatic oligomer is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0134] The weight-average molecular weight (Mw) of the aromatic oligomer is preferably 300 or more, more preferably 500 or more, even more preferably 1,000 or more, and usually less than 3,000, preferably 2,800 or less, more preferably 2,500 or less, and may also be 2,000 or less. The weight-average molecular weight (Mw) of the aromatic oligomer is the value obtained on a standard polystyrene basis by gel permeation chromatography.

[0135] Examples of aromatic oligomers include polystyrene, poly-α-methylstyrene, poly-4-methylstyrene, styrene / α-methylstyrene copolymer, styrene / 4-methylstyrene copolymer, α-methylstyrene / 4-methylstyrene copolymer, and styrene / α-methylstyrene / 4-methylstyrene copolymer. Aromatic oligomers may be used individually or in combination of two or more.

[0136] Commercially available aromatic oligomers may be used. Examples of commercially available aromatic oligomers include Picolastic A5 (polystyrene, softening point 5°C, Mw 350), Picolastic A-75 (polystyrene, softening point 74°C, Mw 1300), Picotex 75 (α-methylstyrene / 4-methylstyrene copolymer, softening point 75°C, Mw 1100), Picotex LC (α-methylstyrene / 4-methylstyrene copolymer, softening point 91°C, Mw 1350), and Crystallet. Aromatic polymers manufactured by Eastman, such as KUSU 3070 (styrene / α-methylstyrene copolymer, softening point 70°C, Mw 950), CRYSTAREX 3085 (styrene / α-methylstyrene copolymer, softening point 85°C, Mw 1150), and CRYSTAREX 3100 (styrene / α-methylstyrene copolymer, softening point 100°C, Mw 1500), and YS Resin SX-100 (polystyrene, softening point 100°C, Mw 2500). FMR-0150 (styrene / aromatic hydrocarbon copolymer, softening point 145°C, Mw 2040; manufactured by Mitsui Chemicals, Inc.), FTR-6100 (styrene / aliphatic hydrocarbon copolymer, softening point 95°C, Mw 1210; manufactured by Mitsui Chemicals, Inc.), FTR-6110 (styrene / aliphatic hydrocarbon copolymer, softening point 110°C, Mw 1570; manufactured by Mitsui Chemicals, Inc.), FTR-6125 (styrene / aliphatic hydrocarbon copolymer) Examples include poly(α-methylstyrene), softening point 125°C, Mw 1950; manufactured by Mitsui Chemicals, Inc., FTR-7100 (styrene / α-methylstyrene / aliphatic hydrocarbon copolymer, softening point 100°C, Mw 1440; manufactured by Mitsui Chemicals, Inc.), FTR-0100 (poly(α-methylstyrene), softening point 100°C, Mw 1960; manufactured by Mitsui Chemicals, Inc.), FTR-2120 (styrene / α-methylstyrene copolymer, softening point 120°C, Mw 2630; manufactured by Mitsui Chemicals, Inc.). In addition to the above, details of aromatic oligomers can also be found in paragraphs 0069-0087 of International Publication No. 2017 / 135168, where the equivalents for aromatic oligomers are used, and this content is incorporated herein by reference.

[0137] When the resin composition of this embodiment contains an aromatic vinyl compound and / or an aromatic oligomer, the total content is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, and may be 4 parts by mass or more, per 100 parts by mass of resin solids. Setting it above the lower limit tends to lower the dielectric constant and dielectric loss tangent. Furthermore, the upper limit of the total content of the aromatic vinyl compound and / or aromatic oligomer is preferably 45 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, and may be 10 parts by mass or less, per 100 parts by mass of resin solids. Setting it below the upper limit tends to improve chemical resistance. The resin composition of this embodiment may contain only one type of aromatic vinyl compound and / or aromatic oligomer, or it may contain two or more types. When containing two or more types, it is preferable that the total amount is within the above range.

[0138] <Filler> The resin composition in this embodiment may contain a filler. By including a filler, the physical properties of the resin composition and its cured product, such as dielectric properties (relative permittivity and / or dielectric loss tangent), flame resistance, and low thermal expansion, can be further improved. Furthermore, it is more preferable that the filler used in this embodiment has excellent low dielectric properties (Dk and / or Df). For example, the filler used in this embodiment preferably has a relative permittivity (Dk) of 8.0 or less, more preferably 6.0 or less, and even more preferably 4.0 or less at a frequency of 10 GHz measured according to the cavity resonator perturbation method. Furthermore, the lower limit of the relative permittivity is practically set to, for example, 2.0 or higher. Furthermore, the filler used in this embodiment preferably has a dielectric loss tangent (Df) of 0.05 or less, more preferably 0.01 or less, at a frequency of 10 GHz measured according to the cavity resonator perturbation method. Furthermore, the lower limit of the dielectric loss tangent is practically set to, for example, 0.0001 or higher.

[0139] The type of filler used in this embodiment is not particularly limited, and those commonly used in the industry can be suitably used. Specifically, silica such as natural silica, fused silica, synthetic silica, amorphous silica, aerosil, hollow silica, etc.; metal oxides such as alumina, white carbon, titanium white, titanium oxide, zinc oxide, magnesium oxide, zirconium oxide, etc.; composite oxides such as zinc borate, zinc stannate, forsterite, barium titanate, strontium titanate, calcium titanate, etc.; nitrides such as boron nitride, aggregated boron nitride, silicon nitride, aluminum nitride, etc.; aluminum hydroxide, heat-treated aluminum hydroxide (aluminum hydroxide that has been heat-treated to reduce some of the crystal water), boehmite, magnesium hydroxide, etc. (including hydrates); acid Examples of inorganic fillers include molybdenum compounds such as molybdenum molasses and zinc molybdate, barium sulfate, clay, kaolin, talc, calcined clay, calcined kaolin, calcined talc, mica, E-glass, A-glass, NE-glass, NER-glass, C-glass, L-glass, D-glass, S-glass, M-glass G20, glass short fibers (including glass powders such as E-glass, T-glass, D-glass, S-glass, and Q-glass), hollow glass, and spherical glass, as well as organic fillers such as styrene-type, butadiene-type, and acrylic-type rubber powders, core-shell-type rubber powders, silicone resin powders, silicone rubber powders, and silicone composite powders. In this embodiment, inorganic fillers are preferred, and more preferably include one or more selected from the group consisting of silica, aluminum hydroxide, talc, aluminum nitride, boron nitride, forsterite, titanium oxide, barium titanate, strontium titanate, and calcium titanate. From the viewpoint of low dielectric properties (Dk and / or Df), it is more preferable to include one or more selected from the group consisting of silica and aluminum hydroxide, and even more preferable to include silica. By using these inorganic fillers, the properties of the cured resin composition, such as heat resistance, dielectric properties, thermal expansion properties, dimensional stability, and flame retardancy, are further improved.

[0140] The filler content in the resin composition in this embodiment can be appropriately set according to the desired properties and is not particularly limited, but is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and may be 30 parts by mass or more, 50 parts by mass or more, 60 parts by mass or more, or 70 parts by mass or more, depending on the application, etc. Setting it above the lower limit tends to result in better low thermal expansion and low dielectric loss tangent of the resulting cured product. Furthermore, the upper limit of the filler content is preferably 300 parts by mass or less, more preferably 250 parts by mass or less, even more preferably 200 parts by mass or less, and even more preferably 180 parts by mass or less, and may be 150 parts by mass or less, 120 parts by mass or less, or 100 parts by mass or less, depending on the application, etc. Setting it below the upper limit tends to result in better moldability of the resin composition. The resin composition in this embodiment may contain only one type of filler or two or more types. When two or more types of fillers are included, it is preferable that the total amount be within the above range.

[0141] In the resin composition of this embodiment, as an example of the embodiment, there is a form in which the filler content is 1 to 95% by mass of the components excluding the solvent, and a form in which it is 10% to 60% by mass is preferred.

[0142] As another example of the embodiment of this model, a configuration that is substantially free of fillers is also possible. "Substantially free of fillers" means, for example, that the filler content is less than 1% by mass of the components excluding the solvent, and preferably less than 0.5% by mass.

[0143] In the resin composition of this embodiment, when a filler, particularly an inorganic filler, is used, a silane coupling agent may be further included. Including a silane coupling agent tends to further improve the dispersibility of the filler and the adhesive strength between the resin component and the filler and glass substrate. Silane coupling agents are not particularly limited and generally include silane coupling agents used for surface treatment of inorganic materials, such as aminosilane compounds (e.g., γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, etc.), epoxysilane compounds (e.g., γ-glycidoxypropyltrimethoxysilane, etc.), vinylsilane compounds (e.g., vinyltrimethoxysilane, vinyltriethoxysilane, tetravinylsilane, triethylvinylsilane, 1,3-vinyltetramethylsiloxane, etc.), styrylsilane compounds (e.g., 4-vinylphenyltrimethoxysilane, etc.), acrylicsilane compounds (e.g., γ-acryloxypropyltrimethoxysilane, etc.), cationicsilane compounds (e.g., N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, etc.), and phenylsilane compounds. Among these, it is preferable to include at least one selected from the group consisting of vinylsilane compounds, styrylsilane compounds, and acrylicsilane compounds, with vinylsilane compounds being more preferable. The silane coupling agent can be used alone or in combination of two or more. The content of the silane coupling agent is not particularly limited, but it is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and preferably 5.0 parts by mass or less, and more preferably 3.0 parts by mass or less, per 100 parts by mass of resin solids in the resin composition. The silane coupling agent can be used alone or in combination of two or more. When two or more are used, the total amount will be within the above range.

[0144] <Dispersant> The resin composition of this embodiment may contain a dispersant. Suitable dispersants are those commonly used for paints, and the type is not particularly limited. Preferably, a copolymer-based wetting dispersant is used, and specific examples include DISPERBYK®-110, 111, 161, 180, 2009, 2152, 2155, BYK®-W996, W9010, W903, and W940, all manufactured by BIC Chemie Japan Co., Ltd.

[0145] If the resin composition of this embodiment contains a dispersant, the lower limit of its content is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and may be 0.3 parts by mass or more, per 100 parts by mass of resin solids in the resin composition. The upper limit of the dispersant content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and may be 3 parts by mass or less, per 100 parts by mass of resin solids in the resin composition. One type of dispersant can be used alone, or two or more types can be used in combination. When two or more types are used, the total amount will be within the above range.

[0146] <Solvent> The resin composition of this embodiment may contain a solvent, and preferably an organic solvent. When a solvent is included, the resin composition of this embodiment is in a form (solution or varnish) in which at least a portion, preferably all, of the above-mentioned resin solids are dissolved or miscible with the solvent. The solvent is not particularly limited as long as it is a polar or nonpolar organic solvent capable of dissolving or miscible with at least a portion, preferably all, of the above-mentioned resin solids. Examples of polar organic solvents include ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), cellosolves (e.g., propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc.), esters (e.g., ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate, methyl methoxypropionate, methyl hydroxyisobutyrate, etc.), and amides (e.g., dimethoxyacetamide, dimethylformamide, etc.). Examples of nonpolar organic solvents include aromatic hydrocarbons (e.g., toluene, xylene, etc.). The solvent can be used individually or in combination of two or more types. When using two or more types, the total amount must be within the above range.

[0147] <Other Components> The resin composition in this embodiment may contain various polymer compounds (such as petroleum resins) other than the components listed above, such as thermoplastic resins and their oligomers, and various additives. Examples of additives include at least one selected from the group consisting of ultraviolet absorbers, antioxidants, curing accelerators (excluding those corresponding to radical polymerization initiators), fluorescent whitening agents, photosensitizers, dyes, pigments, thickeners, flow regulators, lubricants, defoamers, leveling agents, gloss agents, and polymerization inhibitors. The content (total amount) of various polymer compounds other than the components listed above in the resin composition in this embodiment is preferably 0 parts by mass or more and less than 10 parts by mass, more preferably 0 parts by mass or more and less than 5 parts by mass, even more preferably 0 parts by mass or more and less than 3 parts by mass, and may be 0 parts by mass or more and less than 1 part by mass, per 100 parts by mass of resin solids. The total amount of the additive is preferably 0 parts by mass or more and less than 5 parts by mass, more preferably 0 parts by mass or more and less than 3 parts by mass, even more preferably 0 parts by mass or more and less than 1 part by mass, and may be 0 parts by mass or more and less than 0.5 parts by mass, per 100 parts by mass of resin solids.

[0148] <Applications> The resin composition of this embodiment is used as a cured product. Specifically, the resin composition of this embodiment can be suitably used as a low dielectric constant material and / or a low dielectric loss tangent material, as a resin composition for electronic materials such as insulating layers for printed circuit boards and materials for semiconductor packages. The resin composition of this embodiment is preferably used as a resin film or a resin composite sheet. It can also be suitably used as a material for prepregs, metal foil-clad laminates, and printed circuit boards. In particular, the resin composition of this embodiment is preferably used as a resin composite sheet that does not contain a base material such as glass cloth. In prepregs, glass cloth acts as a base material to maintain toughness, but in resin films without glass cloth, toughness tends to decrease. Such a decrease in toughness has been a concern due to the deterioration of transportability before curing and the deterioration of crack resistance after curing. The resin composition of this embodiment is extremely beneficial in that it can avoid these problems.

[0149] The resin composition of this embodiment preferably has a low relative permittivity (Dk) and dielectric loss tangent (Df) in its cured product. More specifically, the dielectric loss tangent (Df) at a frequency of 10 GHz, measured by the cavity resonator perturbation method in accordance with JIS C2138:2007 for a sample molded from the resin composition to a thickness of 0.8 mm and a size of 1 mm x 100 mm, is preferably 0.0030 or less, and more preferably 0.0025 or less. There is no particular lower limit for the dielectric loss tangent (Df), but for example, 0.0001 or more is practical. Furthermore, the relative permittivity (Dk) at a frequency of 10 GHz, measured by the cavity resonator perturbation method in accordance with JIS C218:2007 for the sample, is preferably 2.50 or less, and more preferably 2.45 or less. There is no particular lower limit for the relative permittivity (Dk), but for example, 0.01 or more is practical. The dielectric loss tangent (Df) and relative permittivity (Dk) of the above-mentioned cured product are measured by the method described in the examples below.

[0150] In the resin composition of this embodiment, it is preferable that 80% by mass or more of the thermosetting resin has a dielectric constant of 2.7 or less at a frequency of 10 GHz (preferably 2.0 to 2.7). By adopting such a configuration, the dielectric properties (Dk and / or Df, particularly Dk) of the resulting resin composition can be made lower. The proportion of the thermosetting resin in the resin composition of this embodiment that has a dielectric constant of 2.7 or less at a frequency of 10 GHz is preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 97% by mass or more, and also 100% by mass or less. Furthermore, in the resin composition of this embodiment, it is preferable that 80% by mass or more of the thermosetting resin has a dielectric loss tangent of 0.0027 or less at a frequency of 10 GHz (preferably 0.0005 to 0.0027 or less, more preferably 0.0005 to 0.0026 or less). By adopting such a configuration, the dielectric properties (Dk and / or Df, particularly Dk) of the resulting resin composition can be made lower. The proportion of compounds in the thermosetting resin contained in the resin composition of this embodiment in which the dielectric loss tangent at a frequency of 10 GHz is 0.0027 or less is preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 97% by mass or more, and also 100% by mass or less.

[0151] <<Resin Film>> The resin film of this embodiment is formed from the resin film of this embodiment. The thickness of the film of this embodiment is preferably 5 μm or more, more preferably 8 μm or more, even more preferably 10 μm or more, and also preferably 200 μm or less, more preferably 150 μm or less, even more preferably 100 μm or less, and may be 50 μm or less. Setting the thickness above the lower limit tends to further improve handling properties. Setting the thickness below the upper limit tends to further improve the effect of suppressing peeling of the resin film from other components.

[0152] The method for manufacturing the resin film is not particularly limited, but one example is to apply (coat) a solution obtained by dissolving the resin composition of this embodiment in a solvent onto a support and then drying it to obtain a resin film. As for the application method (coating method), for example, the solution obtained by dissolving the resin composition of this embodiment in a solvent is applied onto the support using a bar coater, die coater, doctor blade, baker applicator, etc. Alternatively, after drying, the support can be peeled off or etched from the multilayer body formed by laminating the support and the resin composition to obtain a resin film. Furthermore, a resin film can also be obtained without using a support by supplying a solution obtained by dissolving the resin composition of this embodiment in a solvent into a mold having a sheet-like cavity and drying it to form a film.

[0153] In the production of the resin film according to this embodiment, the drying conditions for removing the solvent are not particularly limited, but since solvent tends to remain in the resin composition at low temperatures and the resin composition hardens at high temperatures, a temperature of 20°C to 200°C for 1 to 90 minutes is preferred. The resin film can be used in an uncured state after the solvent has been dried, or it can be used in a semi-cured (B-stage) state as needed. The thickness of the resin film can be adjusted by the concentration of the solution of the resin composition according to this embodiment used for coating and the coating thickness.

[0154] The resin film of this embodiment typically does not contain a substrate. The substrate referred to here is exemplified by the substrates shown in the prepreg section described later, and glass cloth is preferred. Such resin films that do not contain a substrate such as glass cloth are preferably used as thin-film build-up materials.

[0155] <<Resin Composite Sheet>> The resin composite sheet of this embodiment has a support and a resin film formed from the resin composition of this embodiment. The resin composite sheet of this embodiment usually does not contain a substrate. The substrate here refers to the substrates shown in the prepreg section described later, and glass cloth is preferred. The resin composite sheet of this embodiment can be used as a build-up film.

[0156] Examples of the support include metal foils such as copper foil, thermoplastic resin films such as polyethylene film, polypropylene film, polycarbonate film, polyethylene terephthalate film, and ethylene tetrafluoroethylene copolymer film, as well as release films obtained by applying a release agent to the surface of the thermoplastic resin film, organic film substrates such as polyimide film, glass plates, SUS (Steel Use Stainless) plates, and FRP (Fiber-Reinforced Plastics). Metal foil or thermoplastic resin film is preferred, and copper foil or polyethylene terephthalate film is more preferred. As for copper foil, for example, a peelable type can be used. Peelable copper foil is an ultrathin copper foil having a release layer, where the release layer is, for example, a copper foil that can be peeled off. When using peelable copper foil, the copper foil is laminated so that the release layer is in contact with a resin film formed from a resin composition. Examples of the defacement layer include a layer containing at least a silicon compound, which can be formed, for example, by applying a silicon compound consisting of one or more silane compounds onto a copper foil or ultrathin copper foil. The means of applying the silicon compound are not particularly limited, and known means such as coating can be used. The adhesion surface of the copper foil to the defacement layer can be treated with a rust-preventive treatment (forming a rust-preventive treatment layer). The rust-preventive treatment can be performed using nickel, tin, zinc, chromium, molybdenum, cobalt, or an alloy thereof.

[0157] The thickness of the demolition layer is not particularly limited, but from the viewpoint of ease of removal and peelability, it is preferably 5 nm or more, more preferably 10 nm or more, even more preferably 20 nm or more, and also preferably 100 nm or less, more preferably 80 nm or less, and even more preferably 60 nm or less.

[0158] Another example of copper foil is an ultra-thin copper foil with a carrier. In this case, it is preferable that the copper foil is arranged in contact with a resin film formed from a resin composition, and the carrier is peeled off after the laminate is formed by heating and pressing.

[0159] A first example of the resin composite sheet of this embodiment is a resin composite sheet in which a thermoplastic resin film (preferably polyethylene terephthalate film) is provided on one side of a resin film formed from the resin composition of this embodiment, and a metal foil (preferably copper foil) is provided on the other side. A second example of the composite resin sheet of this embodiment is a resin composite sheet in which a thermoplastic resin film (preferably polyethylene terephthalate film) is provided on both sides of a resin film formed from the resin composition of this embodiment.

[0160] A third example of the resin composite sheet of this embodiment is a resin composite sheet in which metal foil (preferably copper foil) is provided on both sides of a resin film formed from the resin composition of this embodiment. In the third example of the resin composite sheet, one side of the resin film is a peelable type copper foil, and the other side is an ultra-thin copper foil with a carrier.

[0161] The thickness of the metal foil is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 1.5 μm or more, preferably 72 μm or less, more preferably 50 μm or less, even more preferably 36 μm or less, even more preferably 18 μm or less, and even more preferably 12 μm or less. Setting the thickness above the lower limit tends to suppress pinholes in the metal foil. Setting the thickness below the upper limit tends to further improve the handling properties of the resin composite sheet.

[0162] The thickness of the thermoplastic resin film is preferably 5 μm or more, more preferably 8 μm or more, even more preferably 10 μm or more, preferably 200 μm or less, more preferably 150 μm or less, even more preferably 100 μm or less, and may be 50 μm or less. Setting the thickness above the lower limit tends to further improve handling properties. Setting the thickness below the upper limit tends to further improve the effect of suppressing peeling of the resin film from other components.

[0163] The thickness of the resin composite sheet is preferably 5.5 μm or more, more preferably 6 μm or more, even more preferably 6.5 μm or more, and also preferably 400 μm or less, more preferably 350 μm or less, even more preferably 300 μm or less, and may be 200 μm or less. Setting the thickness above the lower limit tends to further improve handling properties. Setting the thickness below the upper limit tends to further improve the effect of suppressing peeling of the resin film from other components.

[0164] Details of the resin composite sheet and the method for manufacturing the same can be found, for example, in paragraphs 0037 to 0067 of Japanese Patent No. 7583362, which are incorporated herein by reference.

[0165] <<Prepreg>> The resin composition of this embodiment can also be used to make a prepreg. The prepreg of this embodiment is formed from a substrate (prepreg substrate) and the resin composition of this embodiment. The prepreg of this embodiment can be obtained, for example, by applying the resin composition of this embodiment to the substrate (e.g., impregnation and / or coating), and then partially curing it by heating (e.g., drying at 120 to 220°C for 2 to 15 minutes). In this case, the amount of resin composition adhering to the substrate, i.e., the amount of resin composition (including hollow silica and filler) relative to the total amount of prepreg after partial curing, is preferably in the range of 20 to 99% by mass, and more preferably in the range of 20 to 80% by mass.

[0166] The substrate is not particularly limited as long as it is a substrate used in various printed circuit board materials. Examples of substrate materials include glass fibers (e.g., E-glass, D-glass, L-glass, S-glass, T-glass, Q-glass, UN-glass, NE-glass, NER-glass, spherical glass, etc.), inorganic fibers other than glass (e.g., quartz, etc.), and organic fibers (e.g., polyimide, polyamide, polyester, liquid crystal polyester, polytetrafluoroethylene, etc.). The form of the substrate is not particularly limited and includes woven fabrics, nonwoven fabrics, rovings, chopped strand mats, and surfacing mats. These substrates may be used individually or in combination of two or more. Among these substrates, woven fabrics that have undergone ultra-opening treatment and densification treatment are preferred from the viewpoint of dimensional stability, and from the viewpoint of strength and low water absorption, the substrate should have a thickness of 200 μm or less and a mass of 250 g / m². ２ The following glass woven fabrics are preferred, and from the viewpoint of moisture absorption and heat resistance, glass woven fabrics surface-treated with silane coupling agents such as epoxysilane and aminosilane are preferred. From the viewpoint of electrical properties, low dielectric glass cloths made of glass fibers exhibiting low dielectric constant and low dielectric loss tangent, such as L-glass, NE-glass, NER-glass, and Q-glass, are more preferred. Examples of low dielectric constant substrates include substrates with a dielectric constant of 5.0 or less (preferably 3.0 to 4.9). Examples of low dielectric loss tangent substrates include substrates with a dielectric loss tangent of 0.006 or less (preferably 0.001 to 0.005). The dielectric constant and dielectric loss tangent are values ​​measured at a frequency of 10 GHz using a perturbation cavity resonator.

[0167] <<Metal Foil Clad Laminate>> The resin composition of this embodiment may also be used in a metal foil clad laminate. The metal foil clad laminate comprises the prepreg of this embodiment and metal foil disposed on one or both sides of the prepreg. For details of the metal foil clad laminate and its manufacturing method, refer to paragraphs 0142-0144 of International Publication No. 2024 / 225152, which are incorporated herein by reference.

[0168] <<Printed Wiring Board>> The printed wiring board of this embodiment includes an insulating layer and a conductive layer disposed on the surface of the insulating layer, wherein the insulating layer includes at least one of a resin film formed from the resin composition of this embodiment and a layer formed from the prepreg. Such a printed wiring board can be manufactured according to conventional methods, and the method of manufacture is not particularly limited. Details of the printed wiring board can be found in paragraphs 0146-0148 of International Publication No. 2024 / 225152, the contents of which are incorporated herein.

[0169] <<Semiconductor Device>> This embodiment also relates to a semiconductor device including the printed circuit board. Details of the semiconductor device can be found in paragraphs 0200 to 0202 of Japanese Patent Application Publication No. 2021-021027, the contents of which are incorporated herein by reference.

[0170] The present invention will be described in more detail below with reference to examples. The materials, amounts used, proportions, processing content, processing procedures, etc., shown in the following examples can be modified as appropriate, as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments, etc., used in the examples are difficult to obtain due to discontinuation or other reasons, measurements can be taken using other instruments with equivalent performance.

[0171] <Measurement of Weight-Average and Number-Average Molecular Weight> The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of compounds (including resins) were measured by gel permeation chromatography (GPC). A liquid delivery pump (Shimadzu Corporation, LC-20AD), a differential refractive index detector (Shimadzu Corporation, RID-20A), and GPC columns (Showa Denko Corporation, GPC KF-801, 802, 803, 804) were used. Tetrahydrofuran was used as the solvent, and the flow rate was 1.0 mL / min at a column temperature of 40°C. A calibration curve using monodisperse polystyrene was prepared and used.

[0172] <Dielectric Properties> The dielectric properties of each component or resin composition in this specification were determined according to the following method. A cured plate with a thickness of 0.8 mm was obtained by using each component or resin composition according to the cured plate manufacturing method described in Example 1 below. The cured plate was dried at 120°C for 60 minutes, and then the dielectric constant (Dk) and dielectric loss tangent (Df) after drying at a frequency of 10 GHz were measured using a cavity resonator. The measurement temperature was 23°C. A Keysight P5005A Keysight Streamline cavity resonator was used.

[0173] The dielectric constants of the components used in the examples or comparative examples described later were measured using the method described above. Maleimide compound (NE-X-9470S), maleimide compound (MIR-3000), polyphenylene ether compound having a carbon-carbon unsaturated double bond at the terminal (D1), aromatic vinyl compounds (LF310T50, O-divinylbenzene), and thermoplastic elastomers (TR2250, SEPTON2104, MD3501) had a dielectric constant of 2.7 or less and a dielectric loss tangent of 0.0026 or less.

[0174] <Measurement of elongation at fracture before and after heat treatment> The thermoplastic elastomers shown below were each vacuum-pressed at a pressure of 3 MPa and a temperature of 200°C for 120 minutes to produce dumbbell-shaped test specimens of type 6 with a thickness of 0.1 mm. The elongation at fracture was measured at a tensile speed of 5 mm / min according to JIS K 6251 (initial elongation: in %). Ten samples were measured, and the median value was selected as the elongation. Furthermore, the elongation at fracture was measured after heating at 150°C for 3 hours (elongation after heating: in %).

[0175] Details of the thermoplastic elastomers used in the examples and comparative examples are shown below. Kraton MD3501: Hydrogenated SEBS elastomer, containing p-methylstyrene units, with a styrene skeleton content of 10-70% by mass. Initial elongation: 400%, Elongation after heating: 550%.

[0176] JSR Corporation's TR2250: Unhydrogenated SEBS elastomer, with a styrene unit content of 52% by mass. Initial elongation: 550%, elongation after heating: 1.5%.

[0177] SEPTON2104, manufactured by Kuraray Co., Ltd.: Hydrogenated SEPS elastomer, styrene unit content is 65% by mass, initial elongation 10%, elongation after heating 2.2%.

[0178] <Synthesis Example 1: Synthesis of Naphthol Aralkyl Cyanate Ester Compounds (SNCN)> 0.47 moles (OH group equivalent) of α-naphthol aralkyl resin (SN495V, OH group equivalent: 236 g / eq., manufactured by Nippon Steel Chemical Co., Ltd.: contains naphthol aralkyl repeating units of 1 to 5) were dissolved in 500 mL of chloroform, and 0.7 moles of triethylamine were added to this solution to prepare Solution 1. While maintaining the temperature at -10°C, Solution 1 was added dropwise over 1.5 hours to 300 g of a chloroform solution of 0.93 moles of cyanogen chloride charged into the reactor, and the mixture was stirred for 30 minutes after the dropwise addition was complete. Subsequently, a mixed solution of 0.1 moles of triethylamine and 30 g of chloroform was added dropwise to the reactor, and the mixture was stirred for 30 minutes to complete the reaction. After filtering off the by-product triethylamine hydrochloride from the reaction solution, the resulting filtrate was washed with 500 mL of 0.1 N hydrochloric acid, followed by four washes with 500 mL of water. This was dried with sodium sulfate, evaporated at 75°C, and then degassed under reduced pressure at 90°C to obtain a brown solid α-naphthol aralkyl type cyanate compound represented by formula (S1) (R in the formula). Ｃ１ ~R Ｃ４ All are hydrogen atoms, n ｃ A mixture of 1 to 5 was obtained. The obtained α-naphthol aralkyl type cyanate ester compound was analyzed by infrared absorption spectroscopy and found to be 2264 cm⁻¹. －１ Absorption of cyanate ester groups was detected in the vicinity.

[0179] <Synthesis Example 2: Synthesis of a polyphenylene ether compound (D1) having a carbon-carbon unsaturated double bond at the terminal> <<Synthesis of a bifunctional phenylene ether oligomer>> CuBr is used in a vertical reactor equipped with a stirring device, thermometer, air inlet tube and baffle plate. ２0.33 g (1.5 mmol) of copper bromide, 0.63 g (3.7 mmol) of N,N'-di-t-butylethylenediamine, 6.95 g (69 mmol) of n-butyldimethylamine, 670 g of toluene, and 320 g of methanol were charged and stirred at a reaction temperature of 40°C until dissolved. In addition, 46.2 g (171 mmol) of 2,2',3,3',5,5'-hexamethyl-(1,1'-biphenyl)-4,4'-diol, 129.5 g (1,060 mmol) of 2,6-dimethylphenol, and CuBr were added in a separate container. ２ 0.33 g (1.5 mmol) of copper bromide, 0.63 g (3.7 mmol) of N,N'-di-t-butylethylenediamine, 6.95 g (69 mmol) of n-butyldimethylamine, 440 g of toluene, and 170 g of methanol were charged and stirred at a reaction temperature of 40°C to dissolve. Then, while bubbling a mixed gas of nitrogen and air adjusted to an oxygen concentration of 8% into the mixture in the polymerization tank, the mixture from the dropping tank was added dropwise over 280 minutes and stirred. After the dropwise addition was complete, 700 g of water in which 7.1 g (16 mmol) of tetrasodium ethylenediaminetetraacetate was dissolved was added to stop the reaction. The aqueous layer and the organic layer were separated, and the organic layer was washed with a 1 M aqueous hydrochloric acid solution, and then with pure water. The obtained solution was concentrated to 50% by mass using an evaporator to obtain 340 g of toluene solution A of phenylene ether resin. The number-average molecular weight in polystyrene equivalents, calculated using the GPC method, was 985. The weight-average molecular weight in polystyrene equivalents, calculated using the GPC method, was 1090, and the hydroxyl group equivalent was 478 g / eq.

[0180] <<Synthesis of Modified Polyphenylene Ether Compound>> In a reactor equipped with a stirrer, thermometer, and reflux tubing, 300 g of toluene solution A of the phenylene ether resin obtained above, 57.5 g (0.38 mol) of vinyl benzyl chloride (AGC Seimi Chemical Co., Ltd., "CMS-P"), 1200 g of methylene chloride, 5 g (0.037 mol) of benzyldimethylamine, 70 g of pure water, and 63 g of 30.5% by mass NaOH aqueous solution were charged, and the mixture was stirred at a reaction temperature of 40°C. After stirring for 24 hours, the organic layer was washed with 1 M hydrochloric acid aqueous solution, and then with pure water. The obtained solution was concentrated and added dropwise to methanol to solidify it, and the solid was recovered by filtration and vacuum dried to obtain 178 g of polyphenylene ether compound (D1) mainly composed of the compound represented by formula (OP-15). The number-average molecular weight in polystyrene terms, calculated by GPC, was 1200, the weight-average molecular weight in polystyrene terms, calculated by GPC, was 1840, the double bond equivalent of the vinyl group was 620 g / eq., and the hydroxyl group equivalent was 48500 g / eq.

[0181] Example 1 1 part by mass of naphthol aralkyl type cyanate ester compound (SNCN) obtained in Synthesis Example 1 above, 30 parts by mass of maleimide compound (DIC Corporation, NE-X-9470S, corresponding to the compound represented by formula (M1)), 16 parts by mass of MIR-3000-70MT (corresponding to the compound represented by formula (M3)), 15 parts by mass of polyphenylene ether compound (D1) having a carbon-carbon unsaturated double bond at the terminal obtained in Synthesis Example 2, and divinylbenzene (Nippon Steel Chemical Co., Ltd.) Material Co., Ltd., LF310T50) 5 parts by mass, Thermoplastic elastomer (Krayton, MD3501) 20 parts by mass, 4-methylstyrene, weight-average molecular weight: 118 (Tokyo Chemical Industries, Ltd.) 3 parts by mass, Phosphorus-based flame retardant (PX-200, Daihachi Chemical Industry Co., Ltd.) 10 parts by mass, Silica (Admatex Co., Ltd., SC4500SQ graded, average particle size, 1.0 μm) 37.5 parts by mass, Powdered silica (Denka Co., Ltd., average particle size (D ５０37.5 parts by mass of 0.6 μm SFP-130MC, 1 part by mass of silane coupling agent (KMB-403, Shin-Etsu Chemical Co., Ltd.), and 0.4 parts by mass of wetting and dispersing agent (DISPERBY K-161, BIC-Chemie Japan Co., Ltd.) were mixed, and the solid content was diluted to 65% by mass with methyl ethyl ketone to obtain a varnish. The amounts of each component indicate the amount of solid content.

[0182] NE-X-9470S In the following example, the average value of n is 2.

[0183] <Preparation of a 0.8 mm thick cured plate test specimen> A mixed resin powder was obtained by evaporating the solvent from the obtained varnish. The mixed resin powder was filled into a mold with sides of 100 mm and a thickness of 0.8 mm, and a pressure of 30 kg / cm² was applied. ２ Then, a vacuum press was performed at a temperature of 220°C for 120 minutes to obtain a hardened plate with sides of 100 mm and a thickness of 0.8 mm.

[0184] <Vickers Crack Length> A hardened plate measuring 25 mm x 25 mm with a thickness of 40 μm was obtained by vacuum pressing at a temperature of 200°C and a pressure of 3 MPa for 20 minutes. The hardened plate obtained by this method was attached to a microscope slide using tape to prepare a sample. A heated sample was also prepared by heating the same sample at 200°C in air for 1 hour. The Vickers hardness test specified in JIS Z 2244-1 was performed using the obtained evaluation samples. Specifically, a Vickers hardness tester was used to induce cracks by pressing the indenter against the sample under the conditions of a load strength of 19.6 N and a holding time of 10 seconds. Cracks were induced in 10 locations, the crack length was measured, and the average value was calculated. The heated sample was also tested and measured in the same manner. The unit of Vickers crack length is expressed in μm.

[0185] The following measuring instrument was used: Vickers tester (HMV-G31-XY-HC): HMV-G series - Features: Analytical measuring instrument (analytical device) Shimadzu Corporation

[0186] <Number of reflows when blistering occurs> The obtained varnish was applied to a copper foil substrate (1.5 μm thick copper foil (MT-FL, manufactured by Mitsui Mining & Smelting Co., Ltd.)) and the solvent was removed by drying at 130°C for 5 minutes to obtain a 15 μm thick resin composite sheet. The resin composite sheets were laminated on both sides of a 100 μm thick copper-clad laminate (HL-832NS, manufactured by Mitsubishi Gas Chemical Co., Ltd.) and a pressure of 30 kg / cm² was applied. ２ A sample measuring 520 mm in length and 420 mm in width was prepared by vacuum pressing at 220°C for 120 minutes. This sample was then reflowed at 260°C using a Tamura Corporation TNV50-568EM-P reflow machine. After the reflow process, the presence of blisters between the copper-clad laminate and the resin composite sheet was checked, and the number of reflow cycles required if even one blister occurred was recorded. This test was repeated 10 times, and the average number of blister occurrences is recorded.

[0187] <Coefficient of Thermal Expansion (CTE)> (CTE: Coefficient of linear Thermal Expansion) The 0.8 mm thick hardened plate obtained above was downsized to 5 mm x 5 mm to obtain an evaluation sample. The obtained evaluation sample was dried at 120°C for 60 minutes, and the coefficient of thermal expansion of the hardened plate was measured by the TMA method (Thermo-Mechanical Analysis) specified in JIS C 6481 5.19, and its value was determined. Specifically, the hardened plate obtained above was heated from 40°C to 340°C at a rate of 10°C per minute using a thermomechanical analyzer (manufactured by TA Instruments), and the coefficient of linear thermal expansion (ppm / °C) was measured. ppm is a volume ratio. For other details, refer to JIS C 6481 5.19 above. The unit is ppm / °C.

[0188] <Number of Crack Initiation Cycles (4-Layer Substrate)> The obtained varnish was applied to a copper foil substrate (1.5 μm thick copper foil (MT-FL, manufactured by Mitsui Mining & Smelting Co., Ltd.)) and the solvent was removed by drying at 130°C for 5 minutes to obtain a 60 μm thick resin composite sheet. At this time, the resin was in a semi-cured state. The fabricated resin composite sheet was laminated and pressed onto an inner core that had been patterned for evaluation, and then BVH processing was performed to create a wiring pattern with 60 μm between walls. The fabricated substrate was placed in a temperature cycling test machine and a temperature cycling test was performed based on JEDEC's C conditions. Specifically, the sample was left to stand in an environment where it was exposed to -65°C for 30 minutes, then returned to room temperature for 5 minutes, and then exposed to 150°C for 30 minutes. After 500 cycles, the sample was taken out and the presence or absence of cracks in the resin between the wiring was evaluated. The timing at which the resulting resin cracks connected between the wiring was used as the criterion for determining crack initiation. The evaluation was as follows. A: Cracks occur after more than 1500 cycles. B: Cracks occur between 1000 and 1500 cycles. C: Cracks occur before 1000 cycles.

[0189] <Number of Crack Initiation Cycles (4-Layer Coreless Chip Mounting Substrate)> Core resin layer: A 100 μm thick prepreg (Mitsubishi Gas Chemical Co., Ltd., product name: GHPL-830NSF) was used to form a core resin layer. On both sides of this prepreg, a 5 μm thick copper foil with a release layer (Mitsui Mining & Smelting Co., Ltd., product name: MT-Ex) was placed so that the release layer side was in contact with the prepreg. A 15 μm thick resin composite sheet (5 μm copper foil with an 18 μm carrier copper foil (Mitsui Mining & Smelting Co., Ltd., product name: MT-Ex) was then laminated using a vacuum press under conditions of 3.0 ± 0.2 MPa pressure, 220 ± 2°C temperature, and a holding time of 120 minutes. After lamination, the 18 μm carrier copper foil was peeled off and the circuit was formed. Next, a 15 μm thick prepreg (Mitsubishi Gas Chemical Co., Ltd., product name: GHPL-830NSF) was laid. FPL73) was laminated using a vacuum press in the same manner with a 5μm copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd., product name: MTEx) attached to an 18μm carrier copper foil, and the carrier copper foil was peeled off to form the circuit. A resin composite sheet with a resin thickness of 15μm (manufactured by Mitsui Mining & Smelting Co., Ltd., product name: MTEx) was laminated onto the same substrate using a vacuum press in the same manner. After physically peeling off the release layer of the copper foil with a release layer that was in contact with the core resin layer of the fabricated laminated substrate, the outermost layer was patterned, solder resist was applied, underfill was injected, chip mounting was performed, and a mold was formed, and then the sample was diced into 14mm squares to obtain an evaluation sample. The prepared evaluation samples were placed in a temperature cycling tester, and temperature cycling tests were conducted based on JEDEC's C conditions. Specifically, the samples were left in an environment where they were exposed to -65°C for 30 minutes, then returned to room temperature for 5 minutes, and then exposed to 150°C for 30 minutes. Every 500 cycles, the samples were removed and checked for cracks on the side opposite the chip mounting surface. Samples with cracks were polished and observed cross-section, and the timing at which the crack penetrated to the chip mounting surface was used as the criterion for crack occurrence.

[0190] The following evaluations were made: A: Cracks occurred after more than 1500 cycles B: Cracks occurred between 1000 and 1500 cycles C: Cracks occurred before 1000 cycles

[0191] Example 2 In Example 1, the content of thermoplastic elastomer (Krayton, MD3501) was set to 15 parts by mass, and 5 parts by mass of thermoplastic elastomer (JSR, TR2250) was added, with the rest of the procedure being the same.

[0192] Example 3 In Example 1, the content of thermoplastic elastomer (Krayton, MD3501) was set to 10 parts by mass, and thermoplastic elastomer (JSR, TR2250) was added in addition to 6 parts by mass and thermoplastic elastomer (Kuraray, SEPTON2104) in addition to 4 parts by mass, with the rest of the procedure being the same.

[0193] Comparative Example 1 In Example 1, the thermoplastic elastomer (Krayton, MD3501) was omitted, and instead, 12 parts by mass of thermoplastic elastomer (JSR, TR2250) and 8 parts by mass of thermoplastic elastomer (Kuraray, SEPTON2104) were added, with the rest of the procedure being the same.

[0194] Comparative Example 2: In Example 1, the thermoplastic elastomer (Krayton, MD3501) was omitted, and 20 parts by mass of thermoplastic elastomer (JSR, TR2250) was added, with the rest of the procedure being the same.

[0195]

[0196] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the intent and scope of the invention.

Claims

1. A resin composition comprising a thermosetting resin containing a maleimide compound and a thermoplastic elastomer (A), wherein a 0.1 mm thick dumbbell-shaped No. 6 test specimen, molded from the thermoplastic elastomer (A) at 200°C and 3 MPa, has a fracture elongation of 200% or more when measured at a tensile speed of 5 mm / min according to JIS K 6251, and the fracture elongation of the test specimen after heating at 150°C for 3 hours is also 200% or more, and the resin composition does not contain a radical polymerization initiator.

2. The resin composition according to claim 1, wherein the content of the thermoplastic elastomer (A) is 5 to 35 parts by mass per 100 parts by mass of resin solids contained in the resin composition.

3. The resin composition according to claim 1, wherein the thermoplastic elastomer (A) is a block copolymer having a styrene skeleton.

4. The resin composition according to claim 1, wherein the proportion of units having a styrene skeleton in the thermoplastic elastomer (A) is 10 to 67% by mass.

5. The resin composition according to claim 1, wherein the thermoplastic elastomer (A) is hydrogenated.

6. The resin composition according to claim 1, wherein the thermoplastic elastomer (A) comprises a unit having a styrene skeleton with a methyl group.

7. The resin composition according to claim 1, wherein the thermoplastic elastomer (A) is a block copolymer having a styrene skeleton, the proportion of units having a styrene skeleton in the thermoplastic elastomer is 10 to 67% by mass, the thermoplastic elastomer (A) is hydrogenated, and the thermoplastic elastomer (A) contains units having a styrene skeleton having a methyl group.

8. The resin composition according to claim 1 or 7, comprising a thermoplastic elastomer other than the thermoplastic elastomer (A), wherein the thermoplastic elastomer other than the thermoplastic elastomer (A) comprises a thermoplastic elastomer (A1) containing unhydrogenated conjugated diene compound units.

9. The resin composition according to claim 1, further comprising a polyphenylene ether compound having a carbon-carbon unsaturated double bond at its terminus.

10. The resin composition according to claim 1, further comprising silica.

11. The resin composition according to claim 1, wherein 80% by mass or more of the thermosetting resin contained in the resin composition has a dielectric constant of 2.7 or less at a frequency of 10 GHz.

12. The resin composition according to claim 1, wherein the content of the thermoplastic elastomer (A) is 5 to 35 parts by mass per 100 parts by mass of resin solids contained in the resin composition, the thermoplastic elastomer (A) is a block copolymer having a styrene skeleton, the proportion of units having a styrene skeleton in the thermoplastic elastomer (A) is 10 to 67% by mass, the thermoplastic elastomer (A) is hydrogenated, the thermoplastic elastomer (A) contains units having a styrene skeleton having a methyl group, further contains a polyphenylene ether compound having a carbon-carbon unsaturated double bond at its terminal, further contains silica, and 80% by mass or more of the thermosetting resin contained in the resin composition has a dielectric constant of 2.7 or less at a frequency of 10 GHz.

13. The resin composition according to claim 12, comprising a thermoplastic elastomer other than the thermoplastic elastomer (A), wherein the thermoplastic elastomer other than the thermoplastic elastomer (A) comprises a thermoplastic elastomer (A1) containing unhydrogenated conjugated diene compound units.

14. A cured product of a resin composition according to any one of claims 1 to 7 and 9 to 13.

15. A resin film formed from the resin composition according to any one of claims 1 to 7 and 9 to 13.

16. The resin film according to claim 15, wherein the resin film does not contain glass cloth.

17. A resin composite sheet having a support and a resin film formed from a resin composition according to any one of claims 1 to 7 and 9 to 13.

18. The resin composite sheet according to claim 17, wherein the support is a metal foil or a thermoplastic resin film.

19. The resin composite sheet according to claim 17, wherein the support is copper foil or polyethylene terephthalate film.

20. The resin composite sheet according to claim 17, wherein the resin film does not contain glass cloth.

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