Resin components, cured products, prepregs, metal foil laminates, resin composite sheets, printed circuit boards, and semiconductor devices.

Abstract

DEPCT69 The products provided include resin components, cured products, prepregs, and foil-coated laminates. Metals, resin composite sheets, printed circuit boards, and semiconductor devices; resin components include: Maleimide compounds (A) containing an aliphatic hydrocarbon group with eight carbon atoms or More than and two or more maleimide groups in the molecule; maleimide compounds (B) containing groups An aliphatic hydrocarbon containing seven or more carbon atoms and two maleimide groups. Or more in molecules; block copolymers (C) with a styrene backbone; and resins (D) which have Aromatic rings and two or more polymerizable unsaturated groups in addition to Block copolymer (C) with a styrene backbone where differences in relative tolerances occur. The ratio between the maleimide compound (A) and the maleimide compound (B) is 0.3 or less;

Description

Resin composition, cured product, prepreg, metal foil-clad laminate, resin composite sheet, printed wiring board, and semiconductor device

[0001] The present invention relates to a resin composition, a cured product, a prepreg, a metal foil-clad laminate, a resin composite sheet, a printed wiring board, and a semiconductor device.

[0002] In recent years, the integration and miniaturization of semiconductor elements used in mobile terminals, electronic devices, communication devices, and the like have accelerated. Accordingly, technologies enabling high-density packaging of semiconductor elements are required, and improvements are also being sought for printed wiring boards, such as substrates for mounting semiconductor elements, which play an important role in this process. Meanwhile, the applications of electronic devices and the like are continuing to diversify and expand. Accordingly, the properties required for printed wiring boards, such as substrates for mounting semiconductor elements, and for the metal foil-clad laminates and prepregs used therein, are becoming more diverse and stricter. Taking these required properties into consideration, various materials and processing methods have been proposed to obtain improved printed wiring boards. One example is the development of improved resin materials for prepregs and resin composite sheets. Such materials are described in Patent Documents 1 to 4.

[0003] JP 2022-058409 A JP 2021-187893 A International Publication No. 2019 / 188189 JP 2018-090728 A

[0004] As described above, the applications of electronic devices and the like are diversifying and expanding, and new resin materials for use in prepregs and the like are being sought. In particular, there is a need for further development of resin compositions capable of providing cured products that exhibit excellent moisture absorption heat resistance and peel strength with metal foil while maintaining excellent low dielectric properties (Dk and / or Df). The present invention aims to solve the above-mentioned problems by providing a resin composition capable of providing cured products that exhibit excellent moisture absorption heat resistance and peel strength with metal foil while maintaining excellent low dielectric properties (Dk and / or Df, particularly Dk), as well as cured products, prepregs, metal foil-clad laminates, resin composite sheets, printed wiring boards, and semiconductor devices.

[0005] In light of the above-mentioned problems, the present inventors have conducted research and found that by using a maleimide compound having a relatively long aliphatic chain in combination with a maleimide compound having a relatively short aliphatic chain and by reducing the difference in the dielectric constants of the cured products thereof, it is possible to obtain a resin composition that can provide a cured product that has excellent moisture absorption heat resistance and peel strength with metal foil while maintaining excellent low dielectric properties (Dk and / or Df, particularly Dk). Specifically, the above-mentioned problems have been solved by the following means. <1> A resin composition comprising: (A) a maleimide compound (A) having an aliphatic hydrocarbon group having 8 or more carbon atoms in the molecule and having two or more maleimide groups; (B) a maleimide compound (B) having an aliphatic hydrocarbon group having 7 or less carbon atoms in the molecule and having two or more maleimide groups; (C) a block copolymer having a styrene skeleton; and (D) a resin other than the block copolymer (C) having an aromatic ring and two or more polymerizable unsaturated groups, wherein the difference between the dielectric constant at a frequency of 10 GHz measured according to a cavity resonance perturbation method between a cured product of the maleimide compound (A) and a cured product of the maleimide compound (B) measured according to the cavity resonance perturbation method is 0.3 or less. <2> The resin composition according to <1>, wherein the dielectric constant at a frequency of 10 GHz measured according to the cavity resonance perturbation method is 2.1 to 2.5. <3> The resin composition according to <1> or <2>, wherein a cured product of the maleimide compound (B) has a dielectric constant of 2.2 to 2.6 at a frequency of 10 GHz, as measured by a cavity resonance perturbation method. <4> The resin composition according to any one of <1> to <3>, wherein a difference between the dielectric constant of the block copolymer (C) having a styrene skeleton at a frequency of 10 GHz, as measured by a cavity resonance perturbation method, and the dielectric constant of a cured product of the maleimide compound (B) at a frequency of 10 GHz, as measured by a cavity resonance perturbation method, is 0.6 or less. <5> The resin composition according to any one of <1> to <4>, wherein the block copolymer (C) having a styrene skeleton has a dielectric constant of 1.9 to 2.2 at a frequency of 10 GHz, as measured by a cavity resonance perturbation method.<6> The resin composition according to any one of <1> to <5>, wherein the difference between the dielectric constant at a frequency of 10 GHz of a cured product of the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups, as measured according to a cavity resonance perturbation method, and the dielectric constant at a frequency of 10 GHz of a cured product of the maleimide compound (B), as measured according to a cavity resonance perturbation method, is 0.3 or less; and the dielectric constant at a frequency of 10 GHz of the cured product of the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups, as measured according to a cavity resonance perturbation method, is 2.2 to 2.6. <7> The resin composition according to any one of <1> to <6>, wherein the dielectric constant at a frequency of 10 GHz of a cured product of the maleimide compound (A), measured according to a cavity resonance perturbation method, the dielectric constant at a frequency of 10 GHz of a cured product of the maleimide compound (B), measured according to a cavity resonance perturbation method, the dielectric constant at a frequency of 10 GHz of the block copolymer (C) having a styrene skeleton, measured according to a cavity resonance perturbation method, and the dielectric constant at a frequency of 10 GHz of a cured product of the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups, measured according to a cavity resonance perturbation method, are each independently 2.0 to 2.6. <8> The resin composition according to any one of <1> to <7>, wherein the content of the maleimide compound (A) is 5 to 40 parts by mass relative to 100 parts by mass of resin solid content, the content of the maleimide compound (B) is 5 to 40 parts by mass relative to 100 parts by mass of resin solid content, the content of the block copolymer (C) having a styrene skeleton is 3 to 40 parts by mass relative to 100 parts by mass of resin solid content, and the content of the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups is 5 to 50 parts by mass relative to 100 parts by mass of resin solid content. <9> The resin composition according to any one of <1> to <8>, wherein the mass ratio ((A) / (B)) of the content of the maleimide compound (A) to the content of the maleimide compound (B) is 30 / 70 to 70 / 30. <10> The resin composition according to any one of <1> to <9>, wherein the maleimide compound (A) has two or more divalent linear aliphatic hydrocarbon groups having 8 to 20 carbon atoms in the molecule. <11> The resin composition according to any one of <1> to <10>, wherein the maleimide compound (A) has a weight average molecular weight of 2,000 to 30,000.<12> The resin composition according to any one of <1> to <11>, wherein the maleimide compound (A) has one or more groups represented by formula (1), and the maleimide groups are each independently linked to the group represented by formula (1) via at least an aliphatic hydrocarbon group having 8 or more carbon atoms. <13> The resin composition according to any one of <1> to <12>, wherein the maleimide compound (A) has a structural unit represented by formula (2): (In formula (2), R １ and R ３ each independently represents a linear aliphatic hydrocarbon group having 8 or more carbon atoms; R ２ represents a hydrocarbon group having an alicyclic structure of a 4- to 10-membered ring.) <14> The resin composition according to any one of <1> to <13>, wherein the maleimide compound (A) includes a compound represented by formula (3): (In formula (3), R １ and R ３ each independently represents a linear aliphatic hydrocarbon group having 8 or more carbon atoms; R ２ represents a hydrocarbon group having an alicyclic structure of 4 to 10 members, and n represents a number from 1 to 10. <15> The resin composition according to any one of <1> to <14>, wherein the maleimide compound (B) has a weight average molecular weight of 350 to 5000. <16> The resin composition according to any one of <1> to <15>, wherein the maleimide compound (B) includes a compound represented by formula (M1): (In formula (M1), R Ｍ１ , R Ｍ２ , R Ｍ３ , and R Ｍ４ R each independently represents a hydrogen atom or an organic group. Ｍ５ and R Ｍ６ each independently represents a hydrogen atom or an alkyl group. Ｍ represents a divalent aromatic group. A is a 4- to 6-membered alicyclic group. 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 Ｍ１０ R each independently represents a hydrogen atom or an alkyl group. Ｍ１１, R Ｍ１２ , R Ｍ１３ , and R Ｍ１４ R each independently represents a hydrogen atom or an organic group. Ｍ１５ each independently represent an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. px represents an integer of 0 to 3. nx represents an integer of 1 to 20.) <17> The resin composition according to any one of <1> to <16>, wherein the maleimide compound (A) includes a compound represented by formula (3), and the maleimide compound (B) includes a compound represented by formula (M1). (In formula (3), R １ and R ３ each independently represents a linear aliphatic hydrocarbon group having 8 or more carbon atoms; R ２ represents a hydrocarbon group having an alicyclic structure of 4 to 10 members, and n represents a number from 1 to 10. (In formula (M1), R Ｍ１ , R Ｍ２ , R Ｍ３ , and R Ｍ４ R each independently represents a hydrogen atom or an organic group. Ｍ５ and R Ｍ６ each independently represents a hydrogen atom or an alkyl group. Ｍ represents a divalent aromatic group. A is a 4- to 6-membered alicyclic group. 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 Ｍ１０ R each independently represents a hydrogen atom or an alkyl group. Ｍ１１ , R Ｍ１２ , R Ｍ１３ , and R Ｍ１４ R each independently represents a hydrogen atom or an organic group. Ｍ１５each independently represent an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. px represents an integer of 0 to 3. nx represents an integer of 1 to 20.) <18> The resin composition according to any one of <1> to <17>, wherein the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups includes at least one of a polymer (V) having a structural unit represented by formula (V) and a polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds. (In formula (V), Ar represents an aromatic hydrocarbon linking group. * represents a bonding position.) <19> The resin composition according to any one of <1> to <18>, wherein the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups includes at least one of a polymer (V) having a structural unit represented by formula (V) and a polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds represented by formula (OP-1). (In formula (V), Ar represents an aromatic hydrocarbon linking group. * represents a bonding position.) (In formula (OP-1), X represents an aromatic group, and —(Y—O)n ２ - represents a polyphenylene ether structure, and R １ , R ２ , and R ３ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group; n １ represents an integer of 1 to 6, and n ２ represents an integer from 1 to 100, and n ３represents an integer of 1 to 4.) <20> The resin composition according to any one of <1> to <19>, further comprising a cyanate ester compound (E). <21> The resin composition according to <20>, wherein a cured product of the cyanate ester compound (E) has a relative dielectric constant of 2.4 to 3.0 at a frequency of 10 GHz, measured according to a cavity resonance perturbation method. <22> The resin composition according to any one of <1> to <21>, further comprising a compound (F) having one polymerizable unsaturated group in the molecule. <23> The resin composition according to any one of <1> to <22>, further comprising a filler (G). <24> The resin composition according to <23>, wherein the content of the filler (G) in the resin composition is 10 to 1,600 parts by mass per 100 parts by mass of resin solids. <25> A cured product of the maleimide compound (A) has a dielectric constant of 2.1 to 2.5 at a frequency of 10 GHz measured according to a cavity resonance perturbation method, a cured product of the maleimide compound (B) has a dielectric constant of 2.2 to 2.6 at a frequency of 10 GHz measured according to a cavity resonance perturbation method, a difference between the dielectric constant of the block copolymer (C) having a styrene skeleton at a frequency of 10 GHz measured according to a cavity resonance perturbation method and the dielectric constant of the cured product of the maleimide compound (B) at a frequency of 10 GHz measured according to a cavity resonance perturbation method is 0.6 or less, and the block copolymer (C) having a styrene skeleton has a dielectric constant of 1.9 to 2.2 at a frequency of 10 GHz measured according to a cavity resonance perturbation method, a difference between the dielectric constant at a frequency of 10 GHz of a cured product of the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups, as measured according to a cavity resonance perturbation method, and the dielectric constant at a frequency of 10 GHz of a cured product of the maleimide compound (B), as measured according to a cavity resonance perturbation method, is 0.3 or less; and a dielectric constant at a frequency of 10 GHz of the cured product of the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups, as measured according to a cavity resonance perturbation method, is 2.2 to 2.6.the dielectric constant at a frequency of 10 GHz of a cured product of the maleimide compound (A), measured according to a cavity resonance perturbation method, the dielectric constant at a frequency of 10 GHz of a cured product of the maleimide compound (B), measured according to a cavity resonance perturbation method, the dielectric constant at a frequency of 10 GHz of the block copolymer (C) having a styrene skeleton, measured according to a cavity resonance perturbation method, and the dielectric constant at a frequency of 10 GHz of a cured product of the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups, measured according to a cavity resonance perturbation method, are each independently 2.0 to 2.6; the content of the maleimide compound (A) is 5 to 40 parts by mass relative to 100 parts by mass of a resin solid content; the content of the maleimide compound (B) is 5 to 40 parts by mass relative to 100 parts by mass of a resin solid content; the content of the block copolymer (C) having a styrene skeleton is 3 to 40 parts by mass relative to 100 parts by mass of a resin solid content; the content of the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups is 5 to 50 parts by mass relative to 100 parts by mass of the resin solid content, the mass ratio ((A) / (B)) of the content of the maleimide compound (A) to the content of the maleimide compound (B) is 30 / 70 to 70 to 30, the maleimide compound (A) has two or more divalent linear aliphatic hydrocarbon groups having 8 to 20 carbon atoms in the molecule, the weight average molecular weight of the maleimide compound (A) is 2,000 to 30,000, the maleimide compound (A) contains a compound represented by formula (3), and the maleimide compound (B) contains a compound represented by formula (M1), the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups contains at least one of a polymer (V) having a structural unit represented by formula (V) and a polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds represented by formula (OP-1), The resin composition according to any one of <1> to <24>, further comprising a cyanate ester compound (E), wherein a cured product of the cyanate ester compound (E) has a relative dielectric constant of 2.4 to 3.0 at a frequency of 10 GHz measured according to a cavity resonance perturbation method, and further comprising a compound (F) having one polymerizable unsaturated group in the molecule. (In formula (3), R １ and R ３each independently represents a linear aliphatic hydrocarbon group having 8 or more carbon atoms; R ２ represents a hydrocarbon group having an alicyclic structure of 4 to 10 members, and n represents a number from 1 to 10. (In formula (M1), R Ｍ１ , R Ｍ２ , R Ｍ３ , and R Ｍ４ R each independently represents a hydrogen atom or an organic group. Ｍ５ and R Ｍ６ each independently represents a hydrogen atom or an alkyl group. Ｍ represents a divalent aromatic group. A is a 4- to 6-membered alicyclic group. 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 Ｍ１０ R each independently represents a hydrogen atom or an alkyl group. Ｍ１１ , R Ｍ１２ , R Ｍ１３ , and R Ｍ１４ R each independently represents a hydrogen atom or an organic group. Ｍ１５ each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. px represents an integer of 0 to 3. nx represents an integer of 1 to 20. (In formula (V), Ar represents an aromatic hydrocarbon linking group. * represents a bonding position.) (In formula (OP-1), X represents an aromatic group, and —(Y—O)n ２ - represents a polyphenylene ether structure, and R １ , R ２ , and R ３ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group; n １ represents an integer of 1 to 6, and n ２ represents an integer from 1 to 100, and n ３represents an integer of 1 to 4.) <26> The resin composition according to <25>, further comprising a filler (G), wherein the content of the filler (G) in the resin composition is 10 to 1,600 parts by mass per 100 parts by mass of resin solids. <27> A cured product of the resin composition according to any one of <1> to <26>. <28> A prepreg formed from a substrate and the resin composition according to any one of <1> to <26>. <29> A metal foil-clad laminate comprising at least one layer formed from the prepreg according to <28>, and metal foil disposed on one or both sides of the layer formed from the prepreg. <30> A resin composite sheet comprising a support and a layer formed from the resin composition according to any one of <1> to <26>, disposed on a surface of the support. <31> A printed wiring board comprising an insulating layer and a conductor layer disposed on a surface of the insulating layer, wherein the insulating layer comprises a layer formed from the resin composition according to any one of <1> to <26>. <32> A semiconductor device comprising the printed wiring board according to <31>.

[0006] The present invention makes it possible to provide a resin composition capable of providing a cured product that has excellent moisture absorption heat resistance and peel strength with metal foil while maintaining excellent low dielectric properties (Dk and / or Df, particularly Dk), as well as a cured product, a prepreg, a metal foil-clad laminate, a resin composite sheet, a printed wiring board, and a semiconductor device.

[0007] Hereinafter, a detailed description will be given of an embodiment of the present invention (hereinafter simply referred to as "the present embodiment"). The following embodiment is merely an example for explaining the present invention, and the present invention is not limited to this embodiment. In this specification, the term "to" is used to mean that the numerical values ​​before and after the term "to" include the upper and lower limits. In this specification, various physical property values ​​and characteristic values ​​are those at 23°C, unless otherwise specified. In the description of a group (atomic group), a notation that does not specify whether it is substituted or unsubstituted encompasses both a group (atomic group) that has no substituent and a group (atomic group) that has a substituent. For example, the term "alkyl group" encompasses not only an alkyl group that has no substituent (an unsubstituted alkyl group) but also an alkyl group that has a substituent (a substituted alkyl group). In this specification, when a notation that does not specify whether it is substituted or unsubstituted is used, unsubstituted is preferred. In this specification, the term "dielectric constant" refers to the ratio of the dielectric constant of a substance to the dielectric constant of a vacuum. In this specification, the term "dielectric constant" may also be simply referred to as "dielectric constant." Furthermore, in this specification, the term "dielectric constant" refers to the dielectric constant at a frequency of 10 GHz measured according to the cavity resonance perturbation method, unless otherwise specified. In this specification, "(meth)acrylic" refers to both or either of acrylic and methacrylic. "(meth)allyl" refers to both or either of allyl and methallyl. When the measurement method, etc. of the specifications shown in this specification differ depending on the year, they are based on the specifications as of January 1, 2023, unless otherwise specified.

[0008] In this specification, the term "resin solids" refers to components excluding fillers and solvents, and is intended to include the maleimide compound (A), the maleimide compound (B), the block copolymer (C), and the resin (D) containing a polymerizable unsaturated group, as well as other thermosetting compounds and other resin additive components (such as flame retardants and other additives) that are blended as necessary.

[0009] <Resin Composition> The resin composition of the present embodiment includes a maleimide compound (A) (sometimes referred to herein as “maleimide compound (A)”) having an aliphatic hydrocarbon group having 8 or more carbon atoms and having two or more maleimide groups in the molecule, a maleimide compound (B) (sometimes referred to herein as “maleimide compound (B)”) having an aliphatic hydrocarbon group having 7 or less carbon atoms and having two or more maleimide groups in the molecule, a block copolymer (C) (sometimes referred to herein as “block copolymer (C)”) having a styrene skeleton, and a resin (D) (sometimes referred to herein as “resin (D) containing a polymerizable unsaturated group)” that contains an aromatic ring and two or more polymerizable unsaturated groups other than the block copolymer (C) having a styrene skeleton, wherein the difference between the dielectric constant at a frequency of 10 GHz measured according to a cavity resonance perturbation method and the dielectric constant at a frequency of 10 GHz measured according to a cavity resonance perturbation method of a cured product of the maleimide compound (A) is 0.3 or less. This configuration allows for the production of a resin composition that can provide a cured product with excellent moisture absorption heat resistance and peel strength with metal foil while maintaining excellent low dielectric properties (Dk and / or Df, particularly Dk). To obtain a cured product of a resin composition with excellent low dielectric properties, it is advantageous for the resin components constituting the resin composition to have a small number of polar groups. In this embodiment, by using a maleimide compound (A) having an aliphatic hydrocarbon group with 8 or more carbon atoms and two or more maleimide groups in the molecule and a block copolymer (C) having a styrene skeleton, the dielectric properties (Dk and / or Df, particularly Dk) of the resulting cured product can be reduced. Furthermore, since the maleimide compound (A) has an aliphatic hydrocarbon group with 8 or more carbon atoms, the maleimide compound (A) has viscosity, which can increase the peel strength of the resulting cured product with respect to metal foil. The block copolymer (C) having a styrene skeleton can also increase adhesion to metal foil and increase peel strength. On the other hand, the maleimide compound (A) tends to have poor heat resistance due to the presence of an aliphatic hydrocarbon group with 8 or more carbon atoms.In this embodiment, the resin composition is sufficiently cured by blending a maleimide compound (B) having an aliphatic hydrocarbon group with 7 or less carbon atoms and two or more maleimide groups in the molecule and a resin (D) containing a polymerizable unsaturated group. As a result, heat resistance can be improved. Furthermore, compounds with low polarity are easily miscible with each other, resulting in good heat resistance. However, when a resin composition does not contain a maleimide compound (A) but contains a maleimide compound (B), a block copolymer (C), and a resin (D) containing a polymerizable unsaturated group, the maleimide compound (B), which has high polarity and a high dielectric constant, separates upon curing, resulting in localized regions exhibiting low dielectric properties, which tends to deteriorate the moisture absorption heat resistance. In this embodiment, it is believed that the use of a combination of maleimide compounds (A) and (B) with a small difference in dielectric constant suppresses localized curing within the resin composition, thereby solving the above-mentioned problem.

[0010] <Maleimide Compound (A)> The resin composition of this embodiment contains a maleimide compound (A) having two or more aliphatic hydrocarbon groups having 8 or more carbon atoms and two or more maleimide groups in the molecule. The maleimide compound (A) has two or more aliphatic hydrocarbon groups having 8 or more carbon atoms in the molecule (per molecule). Because the maleimide compound (A) contains an aliphatic hydrocarbon group having 8 or more carbon atoms, it has low polarity and can reduce the dielectric properties (Dk and / or Df, particularly Dk) of the resulting cured product. Furthermore, because the maleimide compound (A) contains an aliphatic hydrocarbon group having 8 or more carbon atoms, the compound itself has viscosity, which can increase the peel strength of the resulting cured product against metal foil. Furthermore, the maleimide compound (A) has two or more maleimide groups in the molecule (per molecule). The maleimide compound (A) is a compound having preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, still more preferably 2 or 3, and even more preferably 2 maleimide groups in the molecule.

[0011] The aliphatic hydrocarbon group contained in the maleimide compound (A) may be any of a linear, branched, or cyclic aliphatic hydrocarbon group, or may be a combination of linear, branched, and cyclic aliphatic hydrocarbon groups.

[0012] The aliphatic hydrocarbon group contained in the maleimide compound (A) is preferably a combination of a linear and / or branched aliphatic hydrocarbon group (preferably a linear aliphatic hydrocarbon group, more preferably a linear aliphatic hydrocarbon group having 8 to 20 carbon atoms, and even more preferably a divalent linear aliphatic hydrocarbon group having 8 to 20 carbon atoms) and an optionally substituted 4- to 10-membered cyclic aliphatic hydrocarbon group (preferably a 6-membered cyclic aliphatic hydrocarbon group). Examples of the substituent on the optionally substituted 4- to 10-membered cyclic aliphatic hydrocarbon group include alkyl groups having 1 to 10 carbon atoms, preferably alkyl groups having 6 to 10 carbon atoms, and more preferably n-hexyl and / or n-octyl. The number of substituents is preferably 1 to 3 per cyclic aliphatic hydrocarbon group (preferably a 6-membered cyclic aliphatic hydrocarbon group). In this embodiment, the aliphatic hydrocarbon group contained in the maleimide compound (A) may contain a carbon-carbon unsaturated bond, but it is preferable that it does not contain a carbon-carbon unsaturated bond.

[0013] The number of carbon atoms in the aliphatic hydrocarbon group of the maleimide compound (A) is 8 or more, preferably 10 or more, and even more preferably 12 or more, for each aliphatic hydrocarbon group. By making the number of carbon atoms equal to or greater than the lower limit, the resulting cured product tends to have better low dielectric properties (Dk and / or Df, particularly Dk) and peel strength against metal foil. Furthermore, the number of carbon atoms in the aliphatic hydrocarbon group of the maleimide compound (A) is preferably 50 or less, more preferably 40 or less, even more preferably 35 or less, even more preferably 30 or less, and even more preferably 25 or less. By making the number of carbon atoms equal to or less than the upper limit, the resulting cured product tends to have better heat resistance.

[0014] The number of aliphatic hydrocarbon groups contained in the maleimide compound (A) molecule is 2 or more, preferably 6 or more, more preferably 9 or more, even more preferably 12 or more, still more preferably 15 or more, and even more preferably 20 or more. By making the number equal to or greater than the lower limit, the low dielectric properties (Dk and / or Df, particularly Dk) and peel strength against metal foil of the resulting cured product tend to be better. Furthermore, the number of aliphatic hydrocarbon groups contained in the maleimide compound (A) molecule is preferably 100 or less, more preferably 75 or less, even more preferably 60 or less, even more preferably 50 or less, and even more preferably 40 or less. By making the number equal to or less than the upper limit, compatibility with other resins when mixing resins tends to be further improved.

[0015] The maleimide compound (A) preferably has two or more, more preferably six or more, and even more preferably eight or more, divalent linear aliphatic hydrocarbon groups having 8 to 20 carbon atoms in the molecule, and preferably has 40 or less, more preferably 30 or less, and even more preferably 20 or less. By setting the number of divalent linear aliphatic hydrocarbon groups having 8 to 20 carbon atoms to the above-mentioned lower limit or more, the resulting cured product tends to have better low dielectric properties (Dk and / or Df, especially Dk) and peel strength against metal foil. Furthermore, by setting the number of divalent linear aliphatic hydrocarbon groups having 8 to 20 carbon atoms to the above-mentioned upper limit or less, the compatibility with other resins when mixing with the resin tends to be improved.

[0016] In this embodiment, it is preferred that the maleimide compound (A) has one or more groups represented by formula (1), and that the maleimide groups are each independently linked to the group represented by formula (1) via at least an aliphatic hydrocarbon group having 8 or more carbon atoms. In this embodiment, it is more preferred that the maleimide group is linked to the group represented by formula (1) via a group consisting of a combination of a divalent linear aliphatic hydrocarbon group having 8 to 20 carbon atoms and a 6-membered cyclic aliphatic hydrocarbon group which may have a substituent, and it is even more preferred that the maleimide group is linked to the group represented by formula (1) exclusively via a group consisting of a combination of a divalent linear aliphatic hydrocarbon group having 8 to 20 carbon atoms and a 6-membered cyclic aliphatic hydrocarbon group which may have a substituent. This configuration tends to result in a cured product with low dielectric properties (Dk and / or Df, particularly Dk) and excellent peel strength against metal foil.

[0017] The maleimide compound (A) preferably has a constitutional unit represented by formula (2). (In formula (2), R １ and R ３ each independently represents a linear aliphatic hydrocarbon group having 8 or more carbon atoms; R ２ represents a hydrocarbon group having an alicyclic structure of a 4- to 10-membered ring.) Maleimide compounds having a structural unit represented by formula (2) tend to have higher stress relaxation ability, and as a result, the resulting cured product tends to have lower dielectric properties (Dk and / or Df, particularly Dk) and better peel strength against metal foil, as well as a lower coefficient of thermal expansion. When a maleimide compound having a structural unit represented by formula (2) contains multiple structural units represented by formula (2), the structural units represented by formula (2) may be the same or different.

[0018] The linear aliphatic hydrocarbon group having 8 or more carbon atoms is more preferably a divalent linear aliphatic hydrocarbon group having 8 to 20 carbon atoms, and even more preferably a divalent linear aliphatic hydrocarbon group having 8 to 15 carbon atoms. The hydrocarbon group having an alicyclic structure having 4 to 10 rings is preferably a cyclic hydrocarbon group having a 6-membered ring which may have a substituent. Examples of the substituent include alkyl groups having 1 to 10 carbon atoms, preferably alkyl groups having 6 to 10 carbon atoms, and more preferably n-hexyl and / or n-octyl groups. The number of substituents is preferably 1 to 3 per 6-membered ring.

[0019] The maleimide compound (A) preferably contains a compound represented by formula (3). Compounds represented by formula (3) tend to have higher stress relaxation ability, and as a result, the resulting cured product tends to have lower dielectric properties (Dk and / or Df, particularly Dk) and better peel strength against metal foil, as well as a lower coefficient of thermal expansion. (In formula (3), R １ and R ３ each independently represents a linear aliphatic hydrocarbon group having 8 or more carbon atoms; R ２ represents a hydrocarbon group having an alicyclic structure of 4 to 10 members, and n represents a number from 1 to 10.) In formula (3), when n is 2 or more, the n constitutional units may be the same or different.

[0020] R in formula (3) １ ~R ３ are each independently R in the above formula (2). １ ~R ３ In formula (3), R １ and R ３ is an octylene group, and R ２ is preferably a cycloalkylene group (preferably a cyclohexylene group) having an n-hexyl group and / or an n-octyl group as a substituent.

[0021] The compound represented by formula (3) is not particularly limited, but examples that can be used include "BMI-3000" and "BMI-5000" manufactured by Designer Molecules Inc., and "SLK-3000" manufactured by Shin-Etsu Chemical Co., Ltd. Use of such compounds tends to further reduce the coefficient of thermal expansion.

[0022] The weight-average molecular weight of the maleimide compound (A) is preferably 2,000 or more, more preferably 3,000 or more, even more preferably 4,000 or more, even more preferably 5,000 or more, even more preferably 6,000 or more, and even more preferably 7,000 or more. By setting the weight-average molecular weight at or above the lower limit, the resulting cured product tends to have better low dielectric properties (Dk and / or Df, particularly Dk) and peel strength against metal foil. Furthermore, the weight-average molecular weight of the maleimide compound (A) is preferably 30,000 or less, more preferably 27,000 or less, even more preferably 25,000 or less, and even more preferably 20,000 or less. Setting the weight-average molecular weight at or below the upper limit tends to further improve compatibility with other resins when mixing the resins. When the resin composition of this embodiment contains two or more maleimide compounds (A), the weight-average molecular weight of the mixture of maleimide compounds (A) is preferably within the above range.

[0023] The dielectric constant of the cured product of the maleimide compound (A), measured according to the cavity resonance perturbation method at a frequency of 10 GHz, is preferably 2.5 or less, more preferably 2.4 or less, even more preferably less than 2.4, and even more preferably 2.3 or less. By setting the dielectric constant at or below the upper limit, the resulting cured product tends to have a better dielectric constant (Dk). Furthermore, the dielectric constant of the cured product of the maleimide compound (A) is preferably 2.1 or more. By setting the dielectric constant at or above the lower limit, the compatibility with other resins when mixing the resin is improved, and the resulting cured product tends to have better electrical properties such as low dielectric characteristics, peel strength against metal foil, and heat resistance. When the resin composition of this embodiment contains two or more maleimide compounds (A), the dielectric constant is a weighted average of the dielectric constants of the cured products of the maleimide compounds (A).

[0024] The content of the maleimide compound (A) in the resin composition of this embodiment is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, even more preferably 8 parts by mass or more, even more preferably 9 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the resin solid content. By setting the content of the maleimide compound (A) at or above the lower limit, the resulting cured product tends to have better low dielectric properties (Dk and / or Df, particularly Dk) and peel strength against metal foil. Furthermore, the upper limit of the content of the maleimide compound (A) is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the resin solid content. By setting the content of the maleimide compound (A) at or below the upper limit, the resulting cured product tends to have better moisture absorption heat resistance. The resin composition of this embodiment may contain only one type of maleimide compound (A), or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0025] <Maleimide Compound (B)> The resin composition of this embodiment contains a maleimide compound (B) having an aliphatic hydrocarbon group with 7 or less carbon atoms and two or more maleimide groups in the molecule. The maleimide compound (B) is a compound that does not have an aliphatic hydrocarbon group with 8 or more carbon atoms in the molecule. By including the maleimide compound (B) that does not have an aliphatic hydrocarbon group with 8 or more carbon atoms in the resin composition of this embodiment, the moisture absorption heat resistance of the resulting cured product can be improved. Furthermore, since the maleimide compound (A) has a long-chain aliphatic hydrocarbon group, it tends to have poor curability. In this embodiment, by using a maleimide compound (B) that does not have a long aliphatic hydrocarbon group, the curing of the resin composition can be accelerated and the moisture absorption heat resistance of the resulting cured product can be improved. Furthermore, in this embodiment, the difference between the dielectric constant at a frequency of 10 GHz of a cured product of maleimide compound (A) measured by the cavity resonance perturbation method and the dielectric constant at a frequency of 10 GHz of a cured product of maleimide compound (B) measured by the cavity resonance perturbation method is 0.3 or less. Compounds with such a small difference in dielectric constant tend to be more compatible due to the small difference in polarity, as described above. As a result, it is presumed that a cured product having excellent low dielectric properties (Dk and / or Df, particularly Dk), peel strength with metal foil, and moisture absorption heat resistance can be obtained. Furthermore, maleimide compound (B) has two or more maleimide groups in its molecule. The number of maleimide groups in the maleimide compound (B) used in this embodiment is preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 or 3, and may even be 2. The lower limit of the carbon number of the aliphatic hydrocarbon group having 7 or less carbon atoms is preferably 1 or more.

[0026] The dielectric constant of the cured product of the maleimide compound (B) used in this embodiment, measured according to the cavity resonance perturbation method at a frequency of 10 GHz, is preferably 2.6 or less, more preferably 2.5 or less, even more preferably less than 2.5, and even more preferably 2.4 or less. By setting the dielectric constant at or below the upper limit, compatibility with the maleimide compound (A) is further improved, and the resulting cured product tends to have better moisture absorption heat resistance. Furthermore, the dielectric constant of the cured product of the maleimide compound (B) is preferably 2.2 or more, more preferably 2.3 or more. By setting the dielectric constant at or above the lower limit, compatibility with other resins when mixing the resins is further improved, and the resulting cured product tends to have better electrical properties such as low dielectric properties, peel strength against metal foil, and heat resistance. When the resin composition of this embodiment contains two or more maleimide compounds (B), the dielectric constant is the weighted average of the dielectric constants of the cured products of the maleimide compounds (B).

[0027] A first embodiment of the maleimide compound (B) includes a compound represented by formula (M1). (In formula (M1), R Ｍ１ , R Ｍ２ , R Ｍ３ , and R Ｍ４ R each independently represents a hydrogen atom or an organic group. Ｍ５ and R Ｍ６ each independently represents a hydrogen atom or an alkyl group. Ｍ represents a divalent aromatic group. A is a 4- to 6-membered alicyclic group. 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 Ｍ１０ R each independently represents a hydrogen atom or an alkyl group. Ｍ１１ , R Ｍ１２ , R Ｍ１３ , and R Ｍ１４ R each independently represents a hydrogen atom or an organic group. Ｍ１５each 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 of 0 to 3. nx represents an integer of 1 to 20.) Here, R Ｍ１５ preferably each independently represent an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group.

[0028] R in the formula Ｍ１ , R Ｍ２ , R Ｍ３ , and R Ｍ４ R 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, even more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, with a methyl group being particularly preferred. Ｍ１ and R Ｍ３ are each independently preferably an alkyl group, and R Ｍ２ and R Ｍ４ is preferably a hydrogen atom. Ｍ５ and R Ｍ６ Each of Ar independently represents a hydrogen atom or an alkyl group, and an alkyl group is preferable. 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, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and among these, a methyl group is particularly preferable. Ｍ represents a divalent aromatic group, preferably a phenylene group, a naphthalenediyl group, a phenanthrenediyl group, or an anthracenediyl group, more preferably a phenylene group, and even more preferably an m-phenylene group. Ｍmay have a substituent, and the substituent 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, still more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. Ｍ A is preferably a 4- to 6-membered alicyclic group, more preferably a 5-membered alicyclic group (preferably a group that forms an indane ring when combined with a benzene ring). Ｍ７ and R Ｍ８ are each 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 R each independently represents a hydrogen atom or an alkyl group, with an alkyl group being more 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, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, with a methyl group being particularly preferred. Ｍ１１ , R Ｍ１２ , R Ｍ１３ , and R Ｍ１４ R 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, even more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, with a methyl group being particularly preferred. Ｍ１２ and R Ｍ１３ are each independently preferably an alkyl group, and R Ｍ１１ and R Ｍ１４ is preferably a hydrogen atom. Ｍ１５each 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 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group, and more 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 of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0. nx represents an integer of 1 to 20. nx may be an integer of 10 or less. The resin composition of this embodiment may contain only one compound (M1) represented by formula (M1) having at least different values ​​of nx, or may contain two or more compounds. When two or more compounds are contained, the average value of nx (average number of repeating units) n in the compound represented by formula (M1) in the resin composition is preferably 0.92 or more, more preferably 0.95 or more, even more preferably 1.0 or more, and even more preferably 1.1 or more, in order to achieve a low melting point (low softening point), low melt viscosity, and excellent handleability. 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 be 5.0 or less. The same applies to formula (M1-2) and the like described below.

[0029] The compound represented by formula (M1) is preferably a compound represented by the following formula (M1-1): (In formula (M1-1), R Ｍ２１ , R Ｍ２２ , R Ｍ２３ , and R Ｍ２４ R each independently represents a hydrogen atom or an organic group. Ｍ２５ and R Ｍ２６R each independently represents a hydrogen atom or an alkyl group. Ｍ２７ , R Ｍ２８ , R Ｍ２９ , and R Ｍ３０ R each independently represents a hydrogen atom or an organic group. Ｍ３１ and R Ｍ３２ R each independently represents a hydrogen atom or an alkyl group. Ｍ３３ , R Ｍ３４ , R Ｍ３５ , and R Ｍ３６ R each independently represents a hydrogen atom or an organic group. Ｍ３７ , R Ｍ３８ , and R Ｍ３９ each independently represents a hydrogen atom or an alkyl group; and nx represents an integer of 1 or more and 20 or less.

[0030] R in the formula Ｍ２１ , R Ｍ２２ , R Ｍ２３ , and R Ｍ２４ R 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, even 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. Ｍ２１ and R Ｍ２３ is preferably an alkyl group, and R Ｍ２２ and R Ｍ２４ is preferably a hydrogen atom. Ｍ２５ and R Ｍ２６ R each independently represents a hydrogen atom or an alkyl group, preferably an alkyl group. 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, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and among these, a methyl group is particularly preferred. Ｍ２７ , R Ｍ２８ , R Ｍ２９ , and R Ｍ３０R each independently represents a hydrogen atom or an organic group, preferably a hydrogen atom. 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, still more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. Ｍ３１ and R Ｍ３２ R each independently represents a hydrogen atom or an alkyl group, preferably an alkyl group. 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, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and among these, a methyl group is particularly preferred. Ｍ３３ , R Ｍ３４ , R Ｍ３５ , and R Ｍ３６ R 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, even 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. Ｍ３３ and R Ｍ３６ is preferably a hydrogen atom, and R Ｍ３４ and R Ｍ３５ is preferably an alkyl group. Ｍ３７ , R Ｍ３８ , and R Ｍ３９ each independently represents a hydrogen atom or an alkyl group, with an alkyl group being 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, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, with a methyl group being particularly preferred. nx represents an integer of 1 to 20. nx may also be an integer of 10 or less.

[0031] The compound represented by formula (M1-1) is preferably a compound represented by the following formula (M1-2): (In formula (M1-2), R Ｍ２１ , R Ｍ２２ , R Ｍ２３ , and R Ｍ２４ R each independently represents a hydrogen atom or an organic group. Ｍ２５and R Ｍ２６ R each independently represents a hydrogen atom or an alkyl group. Ｍ２７ , R Ｍ２８ , R Ｍ２９ , and R Ｍ３０ R each independently represents a hydrogen atom or an organic group. Ｍ３１ and R Ｍ３２ R each independently represents a hydrogen atom or an alkyl group. Ｍ３３ , R Ｍ３４ , R Ｍ３５ , and R Ｍ３６ R each independently represents a hydrogen atom or an organic group. Ｍ３７ , R Ｍ３８ , and R Ｍ３９ each independently represents a hydrogen atom or an alkyl group; and nx represents an integer of 1 or more and 20 or less.

[0032] 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 formula (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 nx, and the preferred ranges are also the same.

[0033] The compound represented by formula (M1-1) is preferably a compound represented by the following formula (M1-3), and more preferably a compound represented by the following formula (M1-4). (In formula (M1-3), nx represents an integer of 1 or more and 20 or less.) nx may be an integer of 10 or less. (In formula (M1-4), nx represents an integer of 1 or more and 20 or less.) nx may be an integer of 10 or less. The compound represented by formula (M1) is ｘ The compound represented by formula (M1) may be a mixture of compounds having different n groups, and a mixture is preferred. The compound represented by formula (M1) may be a single compound or a mixture of two or more compounds. Examples of the mixture include compounds having n groups, ｘ a mixture of compounds with different R Ｍ７ , R Ｍ８ , R Ｍ１５ a mixture of compounds in which the types of substituents are different, a mixture of compounds in which the bonding positions (meta position, para position, ortho position) of the maleimide group and the other group on the benzene ring are different, and a mixture of compounds in which two or more of the above-mentioned differences are combined.

[0034] A second embodiment of the maleimide compound (B) includes a compound represented by formula (M5).

[0035] (In formula (M5), R ５８ each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group; R ５９ each independently represents a hydrogen atom or a methyl group; n ６ represents an integer of 1 or more.) R ５８ are each independently preferably one 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. ５９ is preferably a methyl group. ６is 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 may be 1. In the compound represented by formula (M5), n ６ The compound represented by formula (M5) may be a mixture of compounds having different n groups, and is preferably a mixture. The compound represented by formula (M5) may be a single compound or a mixture of two or more compounds. Examples of the mixture include compounds having n groups, ６ a mixture of compounds with different R ５８ a mixture of compounds in which the types of substituents are different, a mixture of compounds in which the bonding positions (meta position, para position, ortho position) of the maleimide group and the other group on the benzene ring are different, and a mixture of compounds in which two or more of the above-mentioned differences are combined.

[0036] The maleimide compound (B) may be produced by a known method, or a commercially available product may be used. Examples of commercially available products include "NE-X-9470S," "NE-X-9480S," "X9-450," and "X9-470" manufactured by DIC Corporation as a compound represented by formula (M1), and "MIR-5000" manufactured by Nippon Kayaku Co., Ltd. as a compound represented by formula (M5). In this embodiment, the maleimide compound (B) preferably contains at least a compound represented by formula (M1).

[0037] The weight-average molecular weight of the maleimide compound (B) used in this embodiment is preferably 350 or more, more preferably 400 or more, and even more preferably 450 or more. By making the weight-average molecular weight equal to or greater than the above-mentioned lower limit, the low dielectric properties and moisture absorption heat resistance of the obtained cured product tend to be further improved. Furthermore, the molecular weight of the maleimide compound (B) is preferably 5000 or less, more preferably 4000 or less, even more preferably 3500 or less, and even more preferably 3000 or less. By making the weight-average molecular weight equal to or less than the above-mentioned upper limit, the solubility in solvents tends to be increased, and the handleability of the resin composition tends to be further improved. When the resin composition of this embodiment contains two or more types of maleimide compounds (B), it is preferable that the weight-average molecular weight of the mixture of maleimide compounds (B) be within the above-mentioned range.

[0038] The content of the maleimide compound (B) in the resin composition of this embodiment is preferably 5 parts by mass or more, more preferably 6 parts by mass or more, even more preferably 8 parts by mass or more, even more preferably 10 parts by mass or more, still more preferably 12 parts by mass or more, and may even be 16 parts by mass or more, relative to 100 parts by mass of the resin solid content. By setting the content of the maleimide compound (B) to the above-mentioned lower limit or more, the moisture absorption heat resistance of the obtained cured product tends to be improved. Furthermore, the upper limit of the content of the maleimide compound (B) is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 25 parts by mass or less, still more preferably 22 parts by mass or less, and still more preferably 20 parts by mass or less, relative to 100 parts by mass of the resin solid content. By setting the content of the maleimide compound (B) to the above-mentioned upper limit or less, the compatibility with the maleimide compound (A) tends to be further improved. The resin composition of this embodiment may contain only one type of maleimide compound (B), or may contain two or more types of maleimide compound (B). When two or more types are contained, the total amount is preferably within the above range.

[0039] In the resin composition of this embodiment, the mass ratio ((A) / (B)) of the content of the maleimide compound (A) to the content of the maleimide compound (B) is preferably 30 / 70 to 70 to 30. Furthermore, the content of the maleimide compound (A) relative to 100 parts by mass of the total content of the maleimide compound (A) and the content of the maleimide compound (B) is more preferably 35 parts by mass or more, even more preferably 40 parts by mass or more, and is preferably 65 parts by mass or less, and more preferably 60 parts by mass or less. By setting the content within the above ranges, the effects of the present invention can be improved in a balanced manner.

[0040] The resin composition of this embodiment may or may not contain a maleimide compound having one maleimide group in the molecule, as well as a maleimide compound having two or more maleimide groups in the molecule other than maleimide compound (A) and maleimide compound (B) (another polyfunctional maleimide compound). Examples of other polyfunctional maleimide compounds include the compounds described in paragraphs 0050 to 0053 of WO 2023 / 026829, the contents of which are incorporated herein by reference. The resin composition of this embodiment may also be configured to be substantially free of maleimide compounds other than maleimide compound (A) and maleimide compound (B). "Substantially free" means that the total amount of maleimide compounds other than maleimide compound (A) and maleimide compound (B) is less than 10 parts by mass, preferably less than 5 parts by mass, more preferably less than 3 parts by mass, even more preferably less than 1 part by mass, and even more preferably less than 0.1 parts by mass, per 100 parts by mass of the total amount of maleimide compound (A) and maleimide compound (B) contained in the resin composition. The resin composition of this embodiment may also be configured to be substantially free of maleimide compounds with a high dielectric constant. "Substantially free" means that the total amount of maleimide compounds with a high dielectric constant is less than 10 parts by mass, preferably less than 5 parts by mass, more preferably less than 3 parts by mass, even more preferably less than 1 part by mass, and even more preferably less than 0.1 parts by mass, per 100 parts by mass of the total amount of maleimide compounds contained in the resin composition. Here, a maleimide compound having a high dielectric constant means that a cured product of the maleimide compound has a dielectric constant of more than 2.6 at a frequency of 10 GHz, measured according to a cavity resonance perturbation method, preferably more than 2.5, and more preferably more than 2.4. The upper limit of the dielectric constant of a cured product of the maleimide compound having a high dielectric constant is not particularly specified, but will usually be 4.0 or less.

[0041] <Block Copolymer (C) Having a Styrene Skeleton> The resin composition of this embodiment contains a block copolymer (C) having a styrene skeleton (block copolymer (C)). By containing the block copolymer (C), the peel strength of the obtained cured product against metal foil is improved, and excellent low dielectric properties (Dk and / or Df, particularly Dk) can be achieved. This is because the toughness of the obtained cured product is improved, and the adhesion to the metal foil is improved.

[0042] The weight-average molecular weight of the block copolymer (C) used in this embodiment is preferably 1,000 or more. By setting the weight-average molecular weight to 1,000 or more, the appearance, low thermal expansion, and crack resistance of the cured product tend to be further improved. The weight-average molecular weight is more preferably 5,000 or more, even more preferably 8,000 or more, even more preferably 10,000 or more, and may even be 50,000 or more or 100,000 or more. The upper limit of the weight-average molecular weight of the block copolymer (C) is preferably 500,000 or less, more preferably 300,000 or less, and even more preferably 250,000 or less. Setting the weight-average molecular weight to the above upper limit or less tends to further improve compatibility with other components. When the resin composition of this embodiment contains two or more block copolymers (C), it is preferable that the weight-average molecular weight of the mixture thereof falls within the above range.

[0043] The block copolymer (C) is a block polymer having at least a styrene skeleton, and is preferably an elastomer containing styrene monomer units and conjugated diene monomer units (hereinafter referred to as "elastomer (c)"). By using such elastomer (c), the resulting cured product tends to have low dielectric properties (Dk and / or Df, especially Dk) and excellent peel strength against metal foil.

[0044] Examples of styrene monomers contained in the elastomer (c) include styrene, α-methylstyrene, p-methylstyrene, divinylbenzene (vinylstyrene), N,N-dimethyl-p-aminoethylstyrene, and N,N-diethyl-p-aminoethylstyrene. Among these, styrene, α-methylstyrene, and p-methylstyrene are preferred from the standpoints of availability and productivity. Among these, styrene is particularly preferred. The content of styrene monomer units in the elastomer (c) is preferably in the range of 10 to 50% by mass of the total monomer units, more preferably 13 to 45% by mass, and even more preferably 15 to 40% by mass. A styrene monomer unit content of 50% by mass or less improves adhesion and tackiness with substrates and the like. Furthermore, a content of 10% by mass or more is preferred because it can suppress increased tack, reduces the occurrence of adhesive residue and stop marks, and tends to improve the ease of peeling between adhesive surfaces. The elastomer (c) may contain only one type of styrene monomer unit, or two or more types. When two or more types are contained, the total amount is preferably in the above range. Regarding the method for measuring the content of styrene monomer units in the elastomer (c) of this embodiment, the description in WO 2017 / 126469 can be referred to, and the contents of this document are incorporated herein by reference. The same applies to the conjugated diene monomer units and the like, which will be described later.

[0045] The elastomer (c) contains a conjugated diene monomer unit. The inclusion of the conjugated diene monomer unit improves the solubility of the elastomer (c) in the resin composition. The conjugated diene monomer is not particularly limited as long as it is a diolefin having one pair of conjugated double bonds. Examples of the conjugated diene monomer include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and farnesene. 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred. The elastomer (c) may contain only one type of conjugated diene monomer unit, or may contain two or more types.

[0046] In the elastomer (c), the mass ratio of the styrene monomer units to the conjugated diene monomer units (styrene monomer units / conjugated diene monomer units) is preferably in the range of 5 / 95 to 80 / 20, more preferably 7 / 93 to 77 / 23, and even more preferably 10 / 90 to 70 / 30. When the mass ratio of the styrene polymer units to the conjugated diene monomer units is in the range of 5 / 95 to 80 / 20, it is possible to suppress the increase in adhesion, maintain high adhesive strength, and improve the ease of peeling between adhesive surfaces.

[0047] The conjugated diene bonds of the elastomer (c) may be entirely hydrogenated, partially hydrogenated, or not hydrogenated at all.

[0048] The elastomer (c) may or may not contain other monomer units in addition to the styrene monomer units and conjugated diene monomer units. Examples of other monomer units include aromatic vinyl compound units other than styrene monomer units. The total of the styrene monomer units and conjugated diene monomer units in the elastomer (c) is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more, of the total monomer units. As described above, the elastomer (c) may contain only one type of styrene monomer unit and one type of conjugated diene monomer unit, or two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0049] The elastomer (c) used in this embodiment may be a block polymer or a random polymer. It may be a hydrogenated elastomer in which the conjugated diene monomer units are hydrogenated, an unhydrogenated elastomer in which no hydrogenation is performed, or a partially hydrogenated elastomer in which only a portion of the conjugated diene monomer units are hydrogenated. An unhydrogenated elastomer or a partially hydrogenated elastomer is preferred. In one embodiment of this embodiment, the elastomer (c) is a hydrogenated elastomer. Here, the term "hydrogenated elastomer" refers to an elastomer in which the double bonds based on the conjugated diene monomer units in the elastomer are hydrogenated, and includes elastomers with a hydrogenation rate (hydrogenation rate) of 80% or more as well as elastomers with a hydrogenation rate (hydrogenation rate) of 100%. The hydrogenation rate of the hydrogenated elastomer is preferably 85% or more, more preferably 90% or more, and even more preferably 95% or more. In this embodiment, the hydrogenation rate is 1 It is calculated from the results of H-NMR spectrum measurement. In one embodiment of this embodiment, the elastomer (c) is an unhydrogenated elastomer. Here, the unhydrogenated elastomer refers to an elastomer in which the proportion of hydrogenated double bonds based on conjugated diene monomer units in the elastomer, i.e., the hydrogenation rate (hydrogenation rate) is 20% or less. The hydrogenation rate is preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less. On the other hand, a partially hydrogenated elastomer refers to an elastomer in which some of the double bonds based on conjugated diene monomer units in the elastomer are hydrogenated, and typically refers to an elastomer in which the hydrogenation rate (hydrogenation rate) is less than 80% but more than 20%.

[0050] Examples of commercially available elastomers (c) used in this embodiment include SEPTON (registered trademark) 2104, V9461, and S8104 manufactured by Kuraray Co., Ltd., Tuftec (registered trademark) H1041, H1043, P2000, and MP10 manufactured by Asahi Kasei Corporation, and DYNARON (registered trademark) 9901P and TR2250 manufactured by JSR Corporation.

[0051] The elastomer used in this embodiment may also be a liquid diene. Liquid diene refers to a liquid elastomer containing a conjugated diene monomer unit. Examples of conjugated diene monomers include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and farnesene. 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred. Examples of liquid dienes used in this embodiment include liquid polybutadiene, liquid polyisoprene, modified liquid polybutadiene, modified liquid polyisoprene, liquid acrylonitrile-butadiene copolymer, and liquid styrene-butadiene copolymer. The number average molecular weight of the liquid diene is not particularly limited as long as it is liquid at 20°C, but is preferably 500 or more and 10,000 or less.

[0052] The styrene skeleton block copolymer (C) used in this embodiment preferably has a dielectric constant at a frequency of 10 GHz, measured according to a cavity resonance perturbation method, of 2.2 or less, more preferably less than 2.2, and preferably 1.9 or more, more preferably 2.0 or more. By setting it to the upper limit or less, the dielectric constant (Dk) of the resulting cured product tends to be better. Furthermore, by setting it to the lower limit or more, the compatibility with other resins when mixing the resin is further improved, and the resulting cured product tends to have better electrical properties such as low dielectric properties, peel strength against metal foil, and heat resistance.

[0053] When the resin composition of the present embodiment contains two or more types of block copolymers (C), the above-mentioned relative dielectric constant is a weighted average value.

[0054] The content of the block copolymer (C) in the resin composition of this embodiment is preferably 3 parts 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, and even more preferably 12 parts by mass or more, per 100 parts by mass of resin solids. By ensuring that the content is equal to or greater than the above-mentioned lower limit, the low dielectric properties (Dk and / or Df, particularly Dk) and peel strength against metal foil of the resulting cured product tend to be further improved. Furthermore, the upper limit of the content of the block copolymer (C) is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, and even more preferably 18 parts by mass or less, per 100 parts by mass of resin solids. By ensuring that the content is equal to or less than the above-mentioned upper limit, the moisture absorption heat resistance of the resulting cured product tends to be further improved. The resin composition of this embodiment may contain only one type of block copolymer (C), or may contain two or more types. When two or more types are contained, the total amount preferably falls within the above-mentioned range. Furthermore, the resin composition of this embodiment may contain a random copolymer in addition to the block copolymer (C), as long as the effects of the present invention are not impaired. Examples of the random copolymer include S.O.E. (registered trademark) S1606, S1613, S1609, and S1605 manufactured by Asahi Kasei Corporation.

[0055] <Resin (D) Containing an Aromatic Ring and Two or More Polymerizable Unsaturated Groups Other than Block Copolymer (C) Having a Styrene Skeleton> The resin composition of this embodiment contains a resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups other than block copolymer (C) having a styrene skeleton (resin (D) containing a polymerizable unsaturated group). By including resin (D) containing a polymerizable unsaturated group, the heat resistance of the resulting cured product is improved and excellent low dielectric properties (particularly Dk) can be achieved. This is because the inclusion of a functional group other than the maleimide group that reacts with the maleimide group improves the degree of curing of the resin composition. A benzene ring is preferred as the aromatic ring contained in resin (D) containing a polymerizable unsaturated group. The polymerizable unsaturated group is preferably a group having a carbon-carbon unsaturated double bond, more preferably a group selected from the group consisting of a (meth)acrylic group, a (meth)allyl group, and a vinylbenzyl group, and even more preferably a group selected from the group consisting of a (meth)acrylic group and a vinylbenzyl group. The polymerizable unsaturated group-containing resin (D) in this embodiment preferably has the polymerizable unsaturated group at a terminal thereof. Furthermore, the polymerizable unsaturated group-containing resin (D) in this embodiment preferably contains two or more of the polymerizable unsaturated groups in one molecule in order to improve the heat resistance of the resulting cured product.

[0056] The resin (D) containing a polymerizable unsaturated group used in the present embodiment preferably contains at least one of a polymer (V) having a structural unit represented by formula (V) and a polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds, and more preferably contains at least one of a polymer (V) having a structural unit represented by formula (V) and a polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds represented by formula (OP-1). (In formula (V), Ar represents an aromatic hydrocarbon linking group. * represents a bonding position.) (In formula (OP-1), X represents an aromatic group, and —(Y—O)n ２ - represents a polyphenylene ether structure, and R １ , R ２ , and R ３each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group; n １ represents an integer of 1 to 6, and n ２ represents an integer from 1 to 100, and n ３ represents an integer of 1 to 4.)

[0057] The resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups used in this embodiment preferably has a dielectric constant of 2.6 or less, more preferably 2.5 or less, even more preferably 2.4 or less, at a frequency of 10 GHz, as measured by a cavity resonance perturbation method, and may be less than 2.4. By setting the dielectric constant to the upper limit or less, compatibility with the maleimide compound (A) tends to be improved. Furthermore, the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups used in this embodiment preferably has a dielectric constant of 2.2 or more, and may be 2.3 or more, as a cured product. By setting the dielectric constant to the upper limit or less, the resulting cured product tends to have a better dielectric constant (Dk). Furthermore, by setting the dielectric constant to the lower limit or more, compatibility with other resins when mixing the resin is improved, and the resulting cured product tends to have better electrical properties, such as low dielectric properties, peel strength against metal foil, and heat resistance.

[0058] When the resin composition of the present embodiment contains two or more types of resin (D) containing a polymerizable unsaturated group, the above-mentioned relative dielectric constant is a weighted average value.

[0059] The content of the resin (D) containing a polymerizable unsaturated group in the resin composition of this embodiment is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and even more preferably 20 parts by mass or more, relative to 100 parts by mass of the resin solid content. The upper limit of the content of the resin (D) containing a polymerizable unsaturated group is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 35 parts by mass or less, and even more preferably 30 parts by mass or less, relative to 100 parts by mass of the resin solid content. The resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups may contain only one type, or two or more types, in the resin composition. When two or more types are contained, it is preferable that the total amount is within the above range.

[0060] <<Polymer (V) Having a Structural Unit Represented by Formula (V)>> The resin composition of the present embodiment preferably contains a polymer (V) having a structural unit represented by formula (V). By containing the polymer (V) having a structural unit represented by formula (V), a resin composition can be obtained in which the cured product has even more excellent low dielectric properties (low dielectric constant, low dielectric loss tangent). (In formula (V), Ar represents an aromatic hydrocarbon linking group. * represents a bonding position.)

[0061] The aromatic hydrocarbon linking group may be a group consisting solely of aromatic hydrocarbons which may have a substituent, or may be a group consisting of a combination of aromatic hydrocarbons which may have a substituent and other linking groups. The aromatic hydrocarbon linking group is preferably a group consisting solely of aromatic hydrocarbons which may have a substituent. Examples of the substituent that the aromatic hydrocarbon may have include the substituent Z (e.g., an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxy group, an amino group, a carboxy group, a halogen atom, etc.). It is also preferable that the aromatic hydrocarbon does not have a substituent. The aromatic hydrocarbon linking group is usually a divalent linking group.

[0062] Specific examples of the aromatic hydrocarbon linking group include a phenylene group, a naphthalenediyl group, an anthracenediyl group, a phenanthrenediyl group, a biphenyldiyl group, and a fluorenediyl group, each of which may have a substituent, and among these, a phenylene group which may have a substituent is preferred. Examples of the substituent include the above-mentioned substituent Z, but it is preferable that the above-mentioned phenylene group and other groups do not have a substituent.

[0063] The structural unit represented by formula (V) more preferably includes at least one of a structural unit represented by formula (V1), a structural unit represented by formula (V2), and a structural unit represented by formula (V3). In the formulae below, * represents a bonding position. Furthermore, hereinafter, the structural units represented by formulas (V1) to (V3) may be collectively referred to as "structural unit (a)."

[0064] In formulas (V1) to (V3), L １ is an aromatic hydrocarbon linking group (preferably having 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and even more preferably 6 to 10 carbon atoms). Specific examples include phenylene groups, naphthalenediyl groups, anthracenediyl groups, phenanthrenediyl groups, biphenyldiyl groups, and fluorenediyl groups, each of which may have a substituent. Of these, phenylene groups, which may have a substituent, are preferred. Examples of the substituent include the aforementioned substituent Z, but it is preferable that the aforementioned groups, such as the phenylene group, be unsubstituted. The compound forming the structural unit (a) is preferably a divinyl aromatic compound, such as divinylbenzene, bis(1-methylvinyl)benzene, divinylnaphthalene, divinylanthracene, divinylbiphenyl, and divinylphenanthrene. Of these, divinylbenzene is particularly preferred. These divinyl aromatic compounds may be used alone, or two or more types may be used as necessary. That is, the structural unit (a) is preferably a structural unit derived from a divinyl aromatic compound.

[0065] As mentioned above, the polymer (V) having the structural unit represented by formula (V) may be a homopolymer of the structural unit (a), but may also be a copolymer with a structural unit derived from another monomer.When the polymer (V) having the structural unit represented by formula (V) is a copolymer, its copolymerization ratio is preferably 3 mol% or more of the structural unit (a), more preferably 5 mol% or more, even more preferably 10 mol% or more, and may even 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 even more preferably 25 mol% or less, even 20 mol% or less.

[0066] An example of a structural unit derived from another monomer is a structural unit (b) derived from an aromatic compound having one vinyl group (monovinyl aromatic compound).

[0067] The structural unit (b) derived from a monovinyl aromatic compound is preferably a structural unit represented by the following formula (V4).

[0068] In formula (V4), L ２ is an aromatic hydrocarbon linking group, and preferred examples thereof include the above L １ Examples include: Ｖ１ is a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms (preferably an alkyl group). Ｖ１ When R is a hydrocarbon group, it preferably has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms. Ｖ１ and L ２ may have the above-mentioned substituent Z.

[0069] When the polymer (V) having a structural unit represented by formula (V) is a copolymer containing a structural unit (b) derived from a monovinyl aromatic compound, examples of the monovinyl aromatic compound 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 aforementioned substituent Z. Furthermore, these monovinyl aromatic compounds may be used alone or in combination with two or more. Among these, the structural unit (b) preferably contains a structural unit derived from at least one selected from the group consisting of o-ethylvinylbenzene, m-ethylvinylbenzene, and p-ethylvinylbenzene. It is more preferable that the structural unit (b) further contains a structural unit derived from styrene in addition to a structural unit derived from at least one selected from the group consisting of o-ethylvinylbenzene, m-ethylvinylbenzene, and p-ethylvinylbenzene.

[0070] When the polymer (V) having the structural unit represented by formula (V) is a copolymer containing the structural unit (b), the copolymerization ratio of the structural unit (b) is preferably 10 mol% or more, more preferably 15 mol% or more, and may further 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.

[0071] Polymer (V) having a structural unit represented by formula (V) may contain structural units other than structural unit (a) and structural unit (b). Examples of such structural units include structural unit (c) derived from a cycloolefin compound. Examples of cycloolefin compounds include hydrocarbons having a double bond within the ring structure. Specific examples include monocyclic 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 having condensed aromatic rings such as indene and acenaphthylene. Examples of norbornene compounds include those described in paragraphs 0037 to 0043 of JP 2018-39995 A, the contents of which are incorporated herein by reference. The cycloolefin compounds exemplified here may further contain the aforementioned substituent Z.

[0072] When the polymer (V) having the structural unit represented by formula (V) is a copolymer containing the structural unit (c), the copolymerization ratio of the 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, and even more preferably 70 mol% or less, and may be 50 mol% or less, or may be 30 mol% or less.

[0073] Polymer (V) having a structural unit represented by formula (V) may further incorporate a 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. Specific 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), and isoprene. The copolymerization ratio of the 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.

[0074] An example of an embodiment of the polymer (V) having a structural unit represented by formula (V) is a polymer that essentially contains the structural unit (a) and contains at least one of the structural units (b) to (d). Further examples include polymers in which the total of the structural units (a) to (d) accounts for 95 mol% or more, and even 98 mol% or more, of all structural units. Another embodiment of the polymer (V) having a structural unit represented by formula (V) is one in which the structural unit (a) is essentially contained, and of all structural units excluding the terminals, structural units containing aromatic rings account for preferably 90 mol% or more, more preferably 95 mol% or more, and even 100 mol%. Note that, in calculating the mol% per total structural units, one structural unit is considered to be derived from one molecule of the monomer (e.g., a divinyl aromatic compound, a monovinyl aromatic compound, etc.) used in the production of the polymer (V) having a structural unit represented by formula (V).

[0075] The method for producing polymer (V) having a structural unit represented by formula (V) is not particularly limited and may be a conventional method, but examples thereof include polymerizing a raw material containing a divinyl aromatic compound (optionally in the presence of a monovinyl aromatic compound, a cycloolefin compound, etc.) 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.

[0076] The structure of the chain end of the polymer (V) having the structural unit represented by formula (V) is not particularly limited, but in terms of the group derived from the divinyl aromatic compound, it may have a structure represented by the following formula (E1). １ is the same as defined in the above formula (V1). * represents the bonding position. *-CH=CH-L １ -CH=CH ２ (E1)

[0077] When a group derived from a monovinyl aromatic compound is at the chain end, the structure may be that of the following formula (E2): ２ and R Ｖ１ are the same as defined in the formula (V4). * represents a bonding position. *-CH=CH-L ２ -R Ｖ１ (E2)

[0078] The molecular weight of the polymer (V) having a structural 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 is preferably 130,000 or less, more preferably 120,000 or less, even more preferably 110,000 or less, and even more preferably 100,000 or less. The molecular weight of the polymer (V) having a structural 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 molecular weight at or above the lower limit, the excellent low dielectric properties (Dk and / or Df) possessed by the polymer (V) having a structural unit represented by formula (V), particularly Df and dielectric properties after moisture absorption, can be effectively exhibited in the cured product of the resin composition. The upper limit 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 molecular weight below the upper limit, poor embedding tends to be less likely when the prepreg or resin sheet is laminated on a circuit-printing substrate. 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 be 15 or less, or may be 12 or less. As for the lower limit, a practical value is 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 10 or more. The Mw and Mn are measured according to the description in the Examples below. When the resin composition of this embodiment contains two or more polymers (V) having a structural unit represented by formula (V), it is preferable that the Mw, Mn, and Mw / Mn of the mixture satisfy the above ranges.

[0079] The vinyl group equivalent of the polymer (V) having a structural 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. The vinyl group equivalent is preferably 1200 g / eq. or less, more preferably 1000 g / eq. or less, and may further 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, or 300 g / eq. or less. By setting the equivalent at or above the lower limit, the storage stability of the resin composition tends to be improved and the flowability of the resin composition tends to be improved. Therefore, moldability is improved, voids are less likely to occur when forming a prepreg, etc., and a more reliable printed wiring board tends to be obtained. On the other hand, by making the content equal to or less than the above upper limit, the heat resistance of the obtained cured product tends to be improved.

[0080] The polymer (V) having a structural unit represented by formula (V) preferably has excellent low dielectric properties when cured. For example, the cured polymer (V) having a structural unit represented by formula (V) used in this embodiment preferably has a relative dielectric constant (Dk) 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, at 10 GHz, measured according to a cavity resonator perturbation method. Furthermore, a practical lower limit for the relative dielectric constant is, for example, 1.80 or more. Furthermore, the cured polymer having a structural unit represented by formula (V) preferably has a dielectric loss tangent (Df) of 0.0030 or less, more preferably 0.0020 or less, and even more preferably 0.0010 or less, at 10 GHz, measured according to a cavity resonator perturbation method. Furthermore, a practical lower limit for the dielectric loss tangent is, for example, 0.0001 or more. The relative dielectric constant (Dk) and dielectric loss tangent (Df) are measured by the following method. 4.5 g of resin powder was placed in a stainless steel mold 100 mm x 30 mm x 1.0 mm high, placed in a vacuum press (Kitagawa Seiki Co., Ltd.), and held at 200 ° C, 220 ° C, and 240 ° C for 1.5 hours, then pressed at a surface pressure of 1.9 MPa to produce a cured plate. The cured plate was then downsized to a width of 1.0 mm, dried at 120 ° C for 60 minutes, and then measured for its relative permittivity (Dk) and dielectric loss tangent (Df) at 10 GHz using a perturbation cavity resonator. The measurement temperature was 23 ° C.

[0081] In this specification, for the polymer (V) having a structural unit represented by the formula (V), the compounds described in paragraphs 0029 to 0058 of WO 2017 / 115813 and their synthesis reaction conditions, etc., the compounds described in paragraphs 0013 to 0058 of JP-A 2018-039995 and their synthesis reaction conditions, etc., the compounds described in paragraphs 0008 to 0043 of JP-A 2018-168347 and their synthesis reaction conditions, etc., the compounds described in paragraphs 0014 to 0042 of JP-A 2006-070136 and their synthesis reaction conditions, etc., the compounds described in paragraphs 0014 to 0061 of JP-A 2006-089683 and their synthesis reaction conditions, etc., the compounds described in paragraphs 0008 to 0036 of JP-A 2008-248001 and their synthesis reaction conditions, etc. can be referenced, and are incorporated herein.

[0082] The lower limit of the content of the polymer (V) having a structural unit represented by formula (V) is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the resin solids. The upper limit of the content of the polymer (V) having a structural unit represented by formula (V) is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, even more preferably 35 parts by mass or less, even more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the resin solids. By ensuring that the content of the polymer (V) having a structural unit represented by formula (V) is equal to or greater than the lower limit, the resulting cured product tends to have excellent low dielectric properties (Dk and / or Df, particularly Dk) and desmear resistance. By ensuring that the content is equal to or less than the upper limit, the peel strength and moisture absorption heat resistance of the resulting cured product against metal foil can be effectively improved. The resin composition may contain only one type of polymer (V) having a structural unit represented by formula (V), or two or more types of polymers. When two or more types are contained, the total amount is preferably within the above range.

[0083] <<Polyphenylene Ether Compound Containing Two or More Carbon-Carbon Unsaturated Double Bonds>> The resin composition of this embodiment may contain a polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds. The polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds is preferably a polyphenylene ether compound having two or more terminal carbon-carbon unsaturated double bonds, more preferably a polyphenylene ether compound having two or more terminal groups selected from the group consisting of (meth)acrylic groups, (meth)allyl groups, and vinylbenzyl groups, and even more preferably a polyphenylene ether compound having two or more terminal groups selected from the group consisting of (meth)acrylic groups and vinylbenzyl groups. The use of these polyphenylene ether compounds tends to more effectively improve the dielectric properties and low water absorption of printed wiring boards and the like. These are described in detail below.

[0084] The polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds is exemplified by a compound having a phenylene ether skeleton represented by the following formula (X1):

[0085] (In formula (X1), R ２４ , R ２５ , R ２６ , and R ２７ may be the same or different and represent an alkyl group having 6 or less carbon atoms, an aryl group, a halogen atom, or a hydrogen atom.

[0086] The polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds is represented by the formula (X2): (In formula (X2), R ２８ , R ２９ , R ３０ , R ３４ , and R ３５ may be the same or different and represent an alkyl group having 6 or less carbon atoms or a phenyl group. ３１ , R ３２ , and R ３３may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group.) and / or a structural 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 are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group. -A- is a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms.

[0087] The polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds is preferably a modified polyphenylene ether compound in which some or all of the terminals are functionalized with ethylenically unsaturated groups (hereinafter, sometimes referred to as "modified polyphenylene ether compound (g)"). A modified polyphenylene ether compound having two or more terminal groups selected from the group consisting of (meth)acrylic groups, (meth)allyl groups, and vinylbenzyl groups is more preferred, and a modified polyphenylene ether compound having two or more terminal groups selected from the group consisting of (meth)acrylic groups and vinylbenzyl groups is even more preferred. By employing such a modified polyphenylene ether compound (g), the dielectric dissipation factor (Df) of the cured product of the resin composition can be further reduced, and the cured product can have low water absorption and high peel strength against metal foil. These compounds may be used alone or in combination of two or more.

[0088] The modified polyphenylene ether compound (g) may be a polyphenylene ether compound represented by formula (OP). (In formula (OP), X represents an aromatic group, and —(Y—O) ｎ１ - represents a polyphenylene ether structure, n1 represents an integer of 1 to 100, and n2 represents an integer of 1 to 4. Rx is a group represented by formula (Rx-1) or formula (Rx-2). (In formula (Rx-1) and formula (Rx-2), R１ , R ２ , and R ３ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. * represents a bonding site with an oxygen atom. Each Mc independently represents a hydrocarbon group having 1 to 12 carbon atoms. z represents an integer of 0 to 4. r represents an integer of 1 to 6.

[0089] n １ and / or n ２ When n is an integer of 2 or more, １ n structural units (Y-O) and / or n ２ The n constitutional units may be the same or different. ２ is preferably 2 or more, more preferably 2.

[0090] In formula (Rx-1) and formula (Rx-2), R １ , R ２ , and R ３ R each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. １ is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. ２ and R ３ are each 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 each of the alkyl group, alkenyl group, and alkynyl group is preferably 5 or less, and more preferably 3 or less.

[0091] In formula (Rx-1), r represents an integer of 1 to 6, preferably an integer of 1 to 5, more preferably an integer of 1 to 4, even more preferably an integer of 1 to 3, still more preferably 1 or 2, and even more preferably 1.

[0092] In formula (Rx-1), each 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, still 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 of 0 to 4, preferably an integer of 0 to 3, more preferably an integer of 0 to 2, still more preferably 0 or 1, and still more preferably 0.

[0093] A specific example of the group represented by formula (Rx-1) is a vinylbenzyl group, and a specific example of the group represented by formula (Rx-2) is a (meth)acryloyl group.

[0094] The modified polyphenylene ether compound (g) is preferably a compound represented by formula (OP-1). (In formula (OP-1), X represents an aromatic group, and —(Y—O)n ２ - represents a polyphenylene ether structure, and R １ , R ２ , and R ３ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group; n １ represents an integer of 1 to 6, and n ２ represents an integer from 1 to 100, and n ３ represents an integer of 1 to 4. ２ and / or n ３ When n is an integer of 2 or more, ２ n structural units (Y-O) and / or n ３ The n constitutional units may be the same or different. ３ is preferably 2 or more, more preferably 2.

[0095] The modified polyphenylene ether compound (g) in this embodiment is preferably a compound represented by formula (OP-2). Here, -(O-X-O)- represents the formula (OP-3): (In formula (OP-3), R４ , R ５ , R ６ , R １０ , and R １１ may be the same or different and are alkyl groups or phenyl groups having 6 or less carbon atoms. ７ , R ８ , and R ９ may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group.) and / or a group represented by formula (OP-4): (In formula (OP-4), R １２ , R １３ , R １４ , R １５ , R １６ , R １７ , R １８ , and R １９ may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group. -A- is a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms.

[0096] In addition, -(Y-O)- represents a group represented by formula (OP-5): (In formula (OP-5), R ２０ , R ２１ may be the same or different and are alkyl groups or phenyl groups having 6 or less carbon atoms. ２２ , R ２３ may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group. ２０ and R ２１ are each independently a group having one or more methyl groups and / or cyclohexyl groups, the rigidity of the resulting resin molecules is increased, and since highly rigid molecules have lower mobility than less rigid molecules, the relaxation time during dielectric relaxation is longer, resulting in excellent low dielectric properties (Dk and / or Df, particularly Dk), which is preferable. An example of formula (OP-5) is the following structure. For the polyphenylene compound having the above structure, the description in JP-A-2019-194312 can be referred to, the contents of which are incorporated herein by reference.

[0097] In formula (OP-2), a and b each independently represent an integer of 0 to 100, and at least one of a and b is an integer of 1 to 100. a and b each independently represent an integer of 0 to 50, more preferably an integer of 1 to 30, and preferably an integer of 1 to 10. When a and / or b is an integer of 2 or greater, two or more -(Y-O)- groups may each independently represent an arrangement of one type of structure, or two or more types of structures may be arranged in blocks or randomly. Furthermore, when a compound represented by formula (OP-2) is contained, the average value of a preferably satisfies 1<a<10, and the average value of b preferably satisfies 1<b<10.

[0098] Examples of -A- in formula (OP-4) include divalent organic groups such as a methylene group, an ethylidene group, a 1-methylethylidene group, a 1,1-propylidene group, a 1,4-phenylenebis(1-methylethylidene) group, a 1,3-phenylenebis(1-methylethylidene) group, a cyclohexylidene group, a phenylmethylene group, a naphthylmethylene group, and a 1-phenylethylidene group, but are not limited to these.

[0099] Among the compounds represented by the above formula (OP-2), R ４ , R ５ , R ６ , R １０ , R １１ , R ２０ , and R ２１ is an alkyl group having 3 or less carbon atoms, and R ７ , R ８ , R ９ , R １２ , R １３ , R １４ , R １５ , R １６ , R １７ , R １８ , R １９ , R ２２ , and R ２３is a hydrogen atom or an alkyl group having 3 or less carbon atoms, and it is particularly preferred that -(O-X-O)- represented by formula (OP-3) or formula (OP-4) is formula (OP-9), formula (OP-10), and / or formula (OP-11), and that -(Y-O)- represented by formula (OP-5) is formula (OP-12) or formula (OP-13). When a and / or b are integers of 2 or more, the two 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 blocks or randomly.

[0100] (In formula (OP-10), R ４４ , R ４５ , R ４６ , and R ４７ may be the same or different and are a hydrogen atom or a methyl group. -B- is a linear, branched or cyclic divalent hydrocarbon group having 20 or less carbon atoms. Specific examples of -B- include the same as the specific examples of -A- in formula (OP-4). (In formula (OP-11), -B- represents a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms.) Specific examples of -B- include the same as the specific examples of -A- in formula (OP-4).

[0101] The polyphenylene ether compound used in the present embodiment 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 an integer of 0 to 100, and at least one of a and b is an integer of 1 to 100.) a and b in formula (OP-14) each independently have the same meanings as 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 an integer of 0 to 100, and at least one of a and b is an integer of 1 to 100.) a and b in formula (OP-15) each independently have the same meanings as a and b in formula (OP-2), and the preferred ranges are also the same.

[0102] The polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds may be produced by a known method, or a commercially available product may be used. Examples of commercially available products include "SA9000" manufactured by SABIC Innovative Plastics, which is a modified polyphenylene ether compound having a terminal methacrylic group. Examples of modified polyphenylene ether compounds having a terminal vinylbenzyl group include "OPE-2St1200" and "OPE-2st2200" manufactured by Mitsubishi Gas Chemical Company. Examples of modified polyphenylene ether compounds having a terminal hydroxyl group, such as "SA90" manufactured by SABIC Innovative Plastics, which have been modified to a vinylbenzyl group using vinylbenzyl chloride or the like, may also be used as modified polyphenylene ether compounds having a terminal hydroxyl group.

[0103] In addition, for details of polyphenylene ether compounds containing two or more carbon-carbon unsaturated double bonds, the descriptions in JP-A-2006-028111, JP-A-2018-131519, WO 2019-138992, and WO 2022-054303 can be referred to, the contents of which are incorporated herein by reference.

[0104] The polystyrene-equivalent number average molecular weight (GPC) of a polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds (preferably a modified polyphenylene ether compound (g)) is preferably 500 or more and 3,000 or less, as determined by gel permeation chromatography (GPC) (details follow the method described in the Examples below). A number average molecular weight of 500 or more tends to further suppress stickiness when the resin composition of the present embodiment is formed into a coating film. A number average molecular weight of 3,000 or less tends to further improve solubility in solvents. Furthermore, the polystyrene-equivalent weight average molecular weight (GPC) of a polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds (preferably a modified polyphenylene ether compound (g)) is preferably 800 or more and 10,000 or less, more preferably 800 or more and 5,000 or less, as determined by GPC (details follow the method described in the Examples below). By setting the content at or above the lower limit, the dielectric constant (Dk) and / or dielectric dissipation factor (Df) (particularly Dk) of the cured product of the resin composition tends to be lower, while by setting the content at or below the upper limit, the solubility, low viscosity, and moldability of the resin composition in solvents when preparing a varnish or the like, as described below, tend to be further improved. Furthermore, in the case of the modified polyphenylene ether compound (g), the terminal carbon-carbon unsaturated double bond equivalent is preferably 400 to 5000 g, and more preferably 400 to 2500 g, per carbon-carbon unsaturated double bond. By setting the content at or above the lower limit, the dielectric constant (Dk) and / or dielectric dissipation factor (Df) (particularly Dk) of the cured product of the resin composition tends to be lower. By setting the content at or below the upper limit, the solubility, low viscosity, and moldability of the resin composition in solvents tend to be further improved.

[0105] The functional group equivalent (carbon-carbon unsaturated double bond equivalent) of a polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds is calculated from the reciprocal of the amount of double bonds determined from the results of measurement using an infrared spectrometer. The double bond equivalent [g / eq.] was determined as follows: A powder of the polyphenylene ether compound is weighed and the weight is recorded. This powder is placed in a measuring flask and then diluted to a predetermined amount with carbon disulfide to prepare a measurement sample. This sample liquid is placed in a measurement cell and set in an infrared spectrophotometer (FT / IR-4600, manufactured by JASCO Corporation). Subsequently, infrared spectroscopy of the sample liquid is performed. In the case of a vinyl group in a polyphenylene ether compound, the 905 cm －１ When the carbon-carbon unsaturated double bond is a methacrylic group, the peak area of ​​the spectrum around 1640 cm is recorded. －１ The peak area of ​​the spectrum near the peak is recorded. From this area value and the calibration curve, the double bond concentration [mol / L] is determined as the measured value. Next, the double bond equivalent is calculated using the following formula: Double bond equivalent [g / eq.] = Powder weight in measurement sample [g] / Double bond concentration [mol / L] × Measurement sample liquid volume [L] The functional group equivalent of other resin components (thermosetting resins) can also be measured using the above method. However, for compounds (monomers) that can be expressed by a single molecular weight, the value calculated as the functional group equivalent by (theoretical molecular weight ÷ number of functional groups) is used preferentially.

[0106] When the resin composition of this embodiment contains a polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds, the lower limit of the content of the polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 8 parts by mass or more, even more preferably 10 parts by mass or more, and even more preferably 13 parts by mass or more, per 100 parts by mass of the resin solids in the resin composition. By setting the content at or above this lower limit, the low dielectric properties (Dk and / or Df, particularly Dk) and moisture absorption heat resistance of the resulting cured product tend to be more excellent. Furthermore, the upper limit of the content of the polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, even more preferably 40 parts by mass or less, even more preferably 35 parts by mass or less, even more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less, per 100 parts by mass of the resin solids in the resin composition. By setting the content to be equal to or less than the upper limit, the heat resistance and chemical resistance of the obtained cured product tend to be better. The resin composition in this embodiment may contain only one polyphenylene ether compound containing two or more carbon-carbon unsaturated double bonds, or may contain two or more polyphenylene ether compounds. When two or more polyphenylene ether compounds are contained, it is preferable that the total amount is within the above range.

[0107] <Difference in Dielectric Ratio Between Components (A) to (D)> In the resin composition of this embodiment, the difference in the dielectric constant between the cured product of the maleimide compound (A) and the cured product of the maleimide compound (B) is 0.3 or less, preferably 0.2 or less, more preferably less than 0.2, and even more preferably 0.1 or less. By setting the difference at or below the above upper limit, the compatibility between the maleimide compound (A) and the maleimide compound (B) is improved, and the resulting cured product tends to have better low dielectric properties (Dk and / or Df, particularly Dk), moisture absorption heat resistance, and peel strength against metal foil. The lower limit of the difference in the dielectric constant between the cured product of the maleimide compound (A) and the cured product of the maleimide compound (B) is 0. Furthermore, the dielectric constant of the cured product of the maleimide compound (A) is usually less than or equal to the dielectric constant of the cured product of the maleimide compound (B).

[0108] Furthermore, in the resin composition of this embodiment, the difference between the dielectric constant of the block copolymer (C) having a styrene skeleton and the dielectric constant of the cured product of the maleimide compound (B) is preferably 0.6 or less, more preferably 0.5 or less, even more preferably 0.4 or less, even more preferably less than 0.4, and even more preferably 0.3 or less. By setting the difference below the upper limit, the compatibility between the block copolymer (C) and the maleimide compound (B) is improved, and the resulting cured product tends to have better low dielectric properties (Dk and / or Df, particularly Dk), moisture absorption heat resistance, and peel strength against metal foil. The lower limit of the difference between the dielectric constant of the block copolymer (C) having a styrene skeleton and the dielectric constant of the cured product of the maleimide compound (B) is 0. Furthermore, the dielectric constant of the block copolymer (C) having a styrene skeleton is usually less than or equal to the dielectric constant of the cured product of the maleimide compound (B).

[0109] Furthermore, in the resin composition of this embodiment, the difference in the dielectric constant between the cured product of the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups and the cured product of the maleimide compound (B) is preferably 0.3 or less, more preferably 0.2 or less, even more preferably less than 0.2, and even more preferably 0.1 or less. By setting the dielectric constant at or below the upper limit, the compatibility between the resin (D) containing a polymerizable unsaturated group and the maleimide compound (B) is improved, and the resulting cured product tends to have better low dielectric properties (Dk and / or Df, particularly Dk), moisture absorption heat resistance, and peel strength against metal foil. The lower limit of the difference in the dielectric constant between the cured product of the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups and the cured product of the maleimide compound (B) is 0. In particular, it is preferable that the difference between the dielectric constant of the cured product of the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups and the dielectric constant of the cured product of the maleimide compound (B) satisfies the above-mentioned requirement, and that the dielectric constant of the cured product of the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups is 2.2 to 2.6.

[0110] Furthermore, in the resin composition of this embodiment, the dielectric constant of the cured product of each of the maleimide compound (A), the maleimide compound (B), the block copolymer (C) having a styrene skeleton, and the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups is preferably 2.6 or less, more preferably 2.5 or less, even more preferably less than 2.5, and even more preferably 2.4 or less. The lower limit is preferably 1.9 or more, more preferably 2.0 or more, and even more preferably greater than 2.0. By setting the dielectric constant of each component to the above upper limit or less, the resulting cured product tends to have better low dielectric properties (Dk and / or Df, especially Dk), moisture absorption heat resistance, and peel strength against metal foil. Furthermore, from the viewpoint of suppressing localized low dielectric properties of the cured product and improving moisture absorption heat resistance, it is preferable that the difference in the dielectric constants of the respective components is not too large. From this viewpoint, the lower limit of the dielectric constant of each of the above components is preferably 2.0 or more, taking practical considerations into account.

[0111] In the resin composition of the present embodiment, of the total amount of the maleimide compound (A), the maleimide compound (B), the block copolymer (C) having a styrene skeleton, and the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups contained in the resin composition, 90% by mass or more (preferably 95% by mass or more, more preferably 97% by mass or more) preferably has a relative dielectric constant of a cured product of 2.6 or less, more preferably 2.5 or less, even more preferably less than 2.5, and still more preferably 2.4 or less, and the lower limit thereof is preferably 1.9 or more, more preferably 2.0 or more, and even more preferably greater than 2.0.

[0112] <Cyanate Ester Compound (E)> The resin composition of this embodiment preferably contains a cyanate ester compound (E). The cyanate ester compound (E) is not particularly limited as long as it contains one or more cyanate groups (cyanato groups) per molecule (preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, still more preferably 2 or 3, and even more preferably 2), and a wide variety of compounds commonly used in the field of printed wiring boards can be used. Furthermore, the cyanate ester compound (E) is preferably a compound in which the cyanate group is directly bonded to an aromatic skeleton (aromatic ring). Examples of the cyanate ester compound (E) include 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, and diallyl bisphenol A-type cyanate ester compounds. Among these, from the viewpoint of further improving the low water absorption of the obtained cured product, at least one selected from the group consisting of phenol novolac cyanate ester compounds, naphthol aralkyl cyanate ester compounds, naphthylene ether cyanate ester compounds, xylene resin cyanate ester compounds, bisphenol M cyanate ester compounds, bisphenol A cyanate ester compounds, and diallyl bisphenol A cyanate ester compounds is preferred, at least one selected from the group consisting of phenol novolac cyanate ester compounds and naphthol aralkyl cyanate ester compounds is more preferred, and naphthol aralkyl cyanate ester compounds are even more preferred. These cyanate ester compounds may be prepared by known methods, or commercially available products may be used.In addition, cyanate ester compounds having a naphthol aralkyl skeleton, naphthylene ether skeleton, xylene skeleton, trisphenolmethane skeleton, or adamantane skeleton have a relatively large functional group equivalent weight and fewer unreacted cyanate ester groups, so cured resin compositions using these compounds tend to have even better low water absorption. Furthermore, due mainly to the presence of an aromatic skeleton or adamantane skeleton, plating adhesion tends to be even more improved. In particular, in this embodiment, naphthol aralkyl cyanate esters represented by formula (7) are preferred. (In formula (7), R ６ Each independently represents a hydrogen atom or a methyl group, and among these, a hydrogen atom is preferred. ２ represents an integer of 1 or more. ２ The upper limit is usually 10, preferably 6. In addition to the above, in this embodiment, the cyanate ester compounds described in WO 2021 / 172317 can be used, the contents of which are incorporated herein by reference.

[0113] The relative dielectric constant at a frequency of 10 GHz of the cured product of the cyanate ester compound (E) used in this embodiment, measured according to a cavity resonance perturbation method, is preferably 3.0 or less, more preferably 2.9 or less, and even more preferably less than 2.9, and a practical lower limit value is 2.4 or more.

[0114] The resin composition of this embodiment preferably contains a cyanate ester compound (E) in an amount that does not impair the effects of the present invention. When the resin composition of this embodiment contains a cyanate ester compound (E), the lower limit of its content is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. When the cyanate ester compound (E) content is 0.1 parts by mass or more, the resulting cured product tends to have excellent heat resistance, flame resistance, chemical resistance, low dielectric constant, low dielectric loss tangent, and insulating properties. When the resin composition of this embodiment contains a cyanate ester compound (E), the upper limit of the cyanate ester compound (E) content is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, even more preferably 10 parts by mass or less, even more preferably 8 parts by mass or less, and even more preferably 6 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. The resin composition in this embodiment may contain only one type of cyanate ester compound (E), or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0115] <Compound (F) Having One Polymerizable Unsaturated Group in the Molecule> The resin composition of this embodiment preferably contains a compound (F) having one polymerizable unsaturated group in the molecule (hereinafter sometimes referred to as "compound (F) containing a polymerizable unsaturated group"). By incorporating the compound (F) containing a polymerizable unsaturated group, the moisture absorption heat resistance of the resulting cured product tends to be further improved. Such a compound reacts with polymerizable unsaturated groups that tend to remain unreacted during curing of the resin composition, thereby reducing the number of polymerizable unsaturated groups in the cured product. In particular, by employing a compound containing a carbon-carbon unsaturated bond at the end of the molecule, it reacts with the resin (D) containing an aromatic ring and two or more polymerizable unsaturated groups, and the moisture absorption heat resistance of the resulting cured product tends to be further improved. The polymerizable unsaturated group is preferably a group having a carbon-carbon unsaturated double bond, more preferably a group selected from the group consisting of a (meth)acrylic group, a (meth)allyl group, and a vinylbenzyl group, even more preferably a group selected from the group consisting of a (meth)acrylic group and a vinylbenzyl group, and even more preferably a vinylbenzyl group.

[0116] The compound (F) containing a polymerizable unsaturated group used in this embodiment is preferably composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, oxygen atoms, nitrogen atoms, and silicon atoms, more preferably composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, oxygen atoms, and silicon atoms, and even more preferably composed only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, and oxygen atoms.The compound (F) containing a polymerizable unsaturated group used in this embodiment may or may not have a polar group.The compound containing a polymerizable unsaturated group used in this embodiment preferably does not have a polar group.Examples of polar groups include amino groups, carboxyl groups, hydroxyl groups, and nitro groups.

[0117] In this embodiment, the molecular weight of the compound (F) containing a polymerizable unsaturated group is preferably 70 or more, more preferably 80 or more, and even more preferably 90 or more. By setting the molecular weight at or above the lower limit, volatilization of the compound (F) containing a polymerizable unsaturated group from the resin composition of this embodiment or a cured product thereof tends to be suppressed. The upper limit of the molecular weight of the compound (F) containing a polymerizable unsaturated group is preferably 500 or less, more preferably 400 or less, even more preferably 300 or less, even more preferably 200 or less, and may even be 150 or less. By setting the molecular weight at or below the upper limit, the effect of enhancing reactivity with the resin (D) containing a polymerizable unsaturated group tends to be further improved. When the resin composition of this embodiment contains two or more compounds (F) containing a polymerizable unsaturated group, the average molecular weight value of the compounds (F) containing a polymerizable unsaturated group is preferably within the above range, and it is more preferable that the molecular weight of each compound is within the above preferred range.

[0118] In this embodiment, the boiling point of the compound (F) containing a polymerizable unsaturated group is preferably 110°C or higher, more preferably 115°C or higher, and even more preferably 120°C or higher. By setting the boiling point at or above the lower limit, volatilization of the compound (F) containing a polymerizable unsaturated group during thermal curing of the resin composition is suppressed, and the compound (F) can be more effectively reacted with the polymerizable unsaturated group of the resin (D) containing a polymerizable unsaturated group. The boiling point of the compound (F) containing a polymerizable unsaturated group is preferably 300°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower. By setting the boiling point at or below the upper limit, the compound (F) is less likely to remain as a residual solvent in the cured product. When the resin composition of this embodiment contains two or more compounds (F) containing a polymerizable unsaturated group, it is sufficient that the average boiling point falls within the above range, but it is preferable that the boiling points of each compound fall within the above preferred range.

[0119] Examples of the compound (F) containing a polymerizable unsaturated group include (meth)acrylic acid ester compounds, aromatic vinyl compounds (preferably styrene-based compounds), saturated fatty acid vinyl compounds, cyanide vinyl compounds, ethylenically unsaturated carboxylic acids, ethylenically unsaturated carboxylic acid anhydrides, ethylenically unsaturated dicarboxylic acid monoalkyl esters, ethylenically unsaturated carboxylic acid amides, vinyl silane compounds (e.g., vinyl trialkoxysilanes), acrylic silane compounds (e.g., acrylic trialkoxysilanes), methacrylic silane compounds (e.g., methacrylic trialkoxysilanes), styryl silane compounds (e.g., styryl trialkoxysilanes), and the like, with aromatic vinyl compounds (preferably styrene-based compounds) being preferred. Specific examples of aromatic vinyl compounds include o-methylstyrene, m-methylstyrene, p-methylstyrene (4-methylstyrene), o,p-dimethylstyrene, o-ethylvinylbenzene, m-ethylvinylbenzene, p-ethylvinylbenzene, methylvinylbiphenyl, and ethylvinylbiphenyl, with p-methylstyrene (4-methylstyrene) being preferred.

[0120] In the resin composition of this embodiment, the content of the compound (F) containing a polymerizable unsaturated group is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 2.5 parts by mass or more, per 100 parts by mass of resin solids. By ensuring that the content is above the lower limit, the amount of unreacted functional groups in the resulting cured product tends to be reduced, and moisture absorption heat resistance tends to be improved. Furthermore, the upper limit of the content of the compound (F) containing a polymerizable unsaturated group is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, even more preferably 10 parts by mass or less, even more preferably 8 parts by mass or less, and even more preferably 5 parts by mass or less, per 100 parts by mass of resin solids. By ensuring that the content is below the upper limit, the low dielectric properties (Dk and / or Df, especially Dk) of the resulting cured product tend to be more excellent. The resin composition of this embodiment may contain only one type of compound (F) containing a polymerizable unsaturated group, or may contain two or more types. When two or more types are contained, the total amount preferably falls within the above range.

[0121] <Filler (G)> The resin composition of this embodiment preferably contains a filler (G). By including the filler (G), the dielectric properties (low dielectric constant, low dielectric loss tangent, etc.), flame resistance, low thermal expansion, and other physical properties of the resin composition and its cured product can be further improved. Furthermore, the filler (G) used in this embodiment more preferably has excellent low dielectric properties (Dk and / or Df). For example, the filler (G) used in this embodiment preferably has a relative dielectric constant (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 a cavity resonator perturbation method. Furthermore, a practical lower limit of the relative dielectric constant is, for example, 2.0 or more. Furthermore, the filler (G) 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 a cavity resonator perturbation method. Furthermore, the lower limit of the dielectric loss tangent is practically, for example, 0.0001 or more.

[0122] The filler (G) used in this embodiment is not particularly limited in type, and can suitably be used as the one generally used in this industry.Specifically, natural silica, fused silica, synthetic silica, amorphous silica, aerosil, hollow silica, etc. silica, alumina, white carbon, titanium white, titanium oxide, zinc oxide, magnesium oxide, zirconium oxide, etc. metal oxide, zinc borate, zinc stannate, forsterite, barium titanate, strontium titanate, calcium titanate, etc. composite oxide, boron nitride, aggregated boron nitride, silicon nitride, aluminum nitride, etc. nitride, aluminum hydroxide, aluminum hydroxide heat treatment product (aluminum hydroxide is heat treated, and part of crystal water is reduced), boehmite, magnesium hydroxide, etc. metal hydroxide (including hydrate), oxide, Examples of fillers include inorganic fillers such as molybdenum and molybdenum compounds such as zinc molybdate, barium sulfate, clay, kaolin, talc, calcined clay, calcined kaolin, calcined talc, mica, E-glass, A-glass, NE-glass, C-glass, L-glass, D-glass, S-glass, M-glass G20, short glass fibers (including fine 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, silicone composite powders, and fluororesin fillers. In this embodiment, inorganic fillers are preferred, and more preferably contain one or more selected from the group consisting of silica, aluminum hydroxide, 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), more preferably contain one or more selected from the group consisting of silica and aluminum hydroxide, and even more preferably contain silica. The use of these inorganic fillers further improves the properties of the cured product of the resin composition, such as heat resistance, dielectric properties, thermal expansion properties, dimensional stability, and flame retardancy.

[0123] The content of the filler (G) in the resin composition of this embodiment can be appropriately set according to the desired properties and is not particularly limited. However, it is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 40 parts by mass or more, even more preferably 60 parts by mass or more, and even more preferably 80 parts by mass or more, relative to 100 parts by mass of the resin solid content in the resin composition. By setting the content at or above the lower limit, the low thermal expansion and low dielectric loss tangent of the resulting cured product tend to be more excellent. Furthermore, the upper limit of the content of the filler (G) is preferably 1600 parts by mass or less, more preferably 1000 parts by mass or less, even more preferably 500 parts by mass or less, even more preferably 300 parts by mass or less, even more preferably 250 parts by mass or less, and may be 200 parts by mass or less, or 120 parts by mass or less, relative to 100 parts by mass of the resin solid content. By setting the content at or below the upper limit, the moldability of the resin composition tends to be further improved. In the resin composition of this embodiment, as an example of a preferred embodiment, the content of the filler (G) is 1 to 95 mass% of the components excluding the solvent, and preferably 30 to 80 mass%. The resin composition of this embodiment may contain only one type of filler (G), or may contain two or more types. When two or more types are contained, it is preferable that the total amount is in the above range.

[0124] When the resin composition of this embodiment uses a filler (G), particularly an inorganic filler, it may further contain a silane coupling agent. The inclusion of a silane coupling agent tends to further improve the dispersibility of the filler (G) and the adhesive strength between the resin component and the filler (G) and the substrate described below. The silane coupling agent is not particularly limited, and examples thereof include silane coupling agents generally used in the 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, etc.), styrylsilane compounds (e.g., p-styryltrimethoxysilane, etc.), acrylicsilane compounds (e.g., γ-acryloxypropyltrimethoxysilane, etc.), cationic silane compounds (e.g., N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, etc.), and phenylsilane compounds. Silane coupling agents may be used alone or in combination of two or more. The content of the silane coupling agent is not particularly limited, but may be 0.1 to 5.0 parts by mass per 100 parts by mass of the resin solids.

[0125] <Other Thermosetting Compounds> The resin composition of this embodiment may or may not contain a thermosetting compound (other thermosetting compound) other than the maleimide compound (A), the maleimide compound (B), the block copolymer (C), the resin (D) containing a polymerizable unsaturated group, the cyanate ester compound (E), and the compound (F) having one polymerizable unsaturated group in the molecule. Examples of other thermosetting compounds include those containing one or more selected from the group consisting of epoxy compounds, phenolic compounds, oxetane resins, and benzoxazine compounds. For details of these components, please refer to the descriptions in paragraphs 0055 to 0062 of WO 2023 / 026829, the contents of which are incorporated herein by reference. In the resin composition of the present embodiment, of the total amount of the maleimide compound (A), the maleimide compound (B), the block copolymer (C) having a styrene skeleton, the resin (D) having an aromatic ring and two or more polymerizable unsaturated groups, the cyanate ester compound (E), the compound (F) having one polymerizable unsaturated group in the molecule, and other thermosetting compounds contained in the resin composition, 90 mass % or more (preferably 95 mass % or more, more preferably 97 mass % or more) of the cured product has a relative dielectric constant at a frequency of 10 GHz measured according to a cavity resonance perturbation method of preferably 2.6 or less, more preferably 2.5 or less, even more preferably less than 2.5, and even more preferably 2.4 or less, and the lower limit is preferably 2.0 or more, more preferably more than 2.0.

[0126] In the resin composition of the present embodiment, the total amount of the maleimide compound (A), the maleimide compound (B), the block copolymer (C), the resin (D) containing a polymerizable unsaturated group, the cyanate ester compound (E), and the compound (F) having one polymerizable unsaturated group in the molecule preferably accounts for 50% by mass or more of the resin solid content, more preferably 60% by mass or more, and even more preferably 70% by mass or more, and may be 80% by mass or more, but is 100% by mass or less.

[0127] <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, including, for example, halogen-based flame retardants such as brominated epoxy resin, brominated polycarbonate, brominated polystyrene, brominated styrene, brominated phthalimide, tetrabromobisphenol A, pentabromobenzyl (meth)acrylate, pentabromotoluene, tribromophenol, hexabromobenzene, decabromodiphenyl ether, bis-1,2-pentabromophenylethane, chlorinated polystyrene, and chlorinated paraffin; red phosphorus; tricresyl phosphate; triphenyl phosphate; and cresyl diphenyl phosphate. Examples of suitable flame retardants include phosphorus-based flame retardants such as phosphate, trixylenyl phosphate, trialkyl phosphate, dialkyl phosphate, tris(chloroethyl)phosphate, phosphazene, 1,3-phenylenebis(2,6-dixylenyl phosphate), and 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; inorganic flame retardants such as aluminum hydroxide, magnesium hydroxide, partial boehmite, boehmite, zinc borate, and antimony trioxide; and silicone-based flame retardants such as silicone rubber and silicone resin. In this embodiment, of these, 1,3-phenylenebis(2,6-dixylenyl phosphate) is preferred because it does not impair the low dielectric properties (Dk and / or Df).

[0128] When the resin composition of this embodiment contains a flame retardant, the content thereof 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 even be 15 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. The lower limit of the content of the flame retardant is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. The flame retardants can be used alone or in combination of two or more. When two or more types are used, the total amount falls within the above range.

[0129] <Active ester compound> The resin composition of the present embodiment may contain an active ester compound within a range that does not impair the effects of the present invention. The active ester compound is not particularly limited, and for example, the description in paragraphs 0064 to 0066 of WO 2021 / 172317 can be referred to, the contents of which are incorporated herein by reference.

[0130] When the resin composition of this embodiment contains an active ester compound, the amount is preferably 1 part by mass or more and preferably 50 parts by mass or less per 100 parts by mass of the resin solid content in the resin composition. The resin composition of this embodiment may contain only one type of active ester compound, or may contain two or more types. When two or more types are contained, it is preferable that the total amount is in the above range. Furthermore, the resin composition of this embodiment may be configured to be substantially free of an active ester compound. "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 the resin solid content in the resin composition.

[0131] <Dispersant> The resin composition of this embodiment may contain a dispersant. As the dispersant, those generally used for paints can be suitably used, and the type is not particularly limited. As the dispersant, a copolymer-based wetting dispersant is preferably used, and specific examples thereof include DISPERBYK (registered trademark)-110, 111, 161, 180, 2009, 2152, 2155, BYK (registered trademark)-W996, W9010, W903, and W940, manufactured by BYK Japan K.K.

[0132] When the resin composition of this embodiment contains a dispersant, the lower limit of the 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 the resin solid content 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 the resin solid content in the resin composition. The dispersants can be used alone or in combination of two or more. When two or more types are used, the total amount falls within the above range.

[0133] <Curing Accelerator> The resin composition of the present embodiment may further contain a curing accelerator. The curing accelerator is not particularly limited, and examples thereof include imidazoles such as 2-ethyl-4-methylimidazole and triphenylimidazole; organic peroxides such as benzoyl peroxide, lauroyl peroxide, acetyl peroxide, parachlorobenzoyl peroxide, di-tert-butyl-di-perphthalate, α,α'-di(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3; azo compounds such as azobisnitrile; N,N-dimethylbenzylamine, N,N-dimethylaniline, N,N-dimethyltoluidine, 2-N-ethylanilinoethanol, tri-n-butylamine, pyridine, quinoline, and N-methylmorpholine. tertiary amines such as triethanolamine, triethylenediamine, tetramethylbutanediamine, and N-methylpiperidine; phenols such as phenol, xylenol, cresol, resorcinol, and catechol; high-temperature decomposition type radical generators such as 2,3-dimethyl-2,3-diphenylbutane; organic metal salts such as lead naphthenate, lead stearate, zinc naphthenate, zinc octylate, manganese octylate, tin oleate, dibutyltin maleate, manganese naphthenate, cobalt naphthenate, and iron acetylacetonate; compounds obtained by dissolving these organic metal salts in hydroxyl group-containing compounds such as phenol and bisphenol; inorganic metal salts such as tin chloride, zinc chloride, and aluminum chloride; and organic tin compounds such as dioctyltin oxide, other alkyl tins, and alkyl tin oxides. Among these, preferred curing accelerators are imidazoles and organic metal salts, with imidazoles being more preferred.

[0134] When the resin composition of this embodiment contains a curing accelerator, the lower limit of the content is preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and even more preferably 0.1 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. The upper limit of the content of the curing accelerator is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 2 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. The curing accelerators can be used alone or in combination of two or more. When two or more types are used, the total amount falls within the above range.

[0135] <Solvent> The resin composition of this embodiment may contain a solvent, and preferably contains an organic solvent. When a solvent is contained, the resin composition of this embodiment is in a form (solution or varnish) in which at least a portion, preferably all, of the various resin solid components described above are dissolved or compatible in the solvent. The solvent is not particularly limited as long as it is a polar organic solvent or a non-polar organic solvent that can dissolve or compatible at least a portion, preferably all, of the various resin solid components described above. 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 non-polar organic solvents include aromatic hydrocarbons (e.g., toluene, xylene, etc.). The solvents may be used alone or in combination of two or more. When two or more solvents are used, the total amount falls within the above range.

[0136] <Other Components> In addition to the above components, the resin composition of this embodiment may contain various polymer compounds such as thermoplastic resins and their oligomers, petroleum resins, and various additives. Examples of additives include ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent brighteners, photosensitizers, dyes, pigments, thickeners, flow adjusters, lubricants, antifoaming agents, leveling agents, gloss agents, and polymerization inhibitors. These additives may be used alone or in combination of two or more.

[0137] <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-tangent material, such as an insulating layer for a printed wiring board, a semiconductor package material, or other electronic material resin composition. The resin composition of this embodiment can be suitably used as a material for a prepreg, a metal foil-clad laminate using a prepreg, a resin composite sheet, and a printed wiring board.

[0138] The resin composition of this embodiment preferably has a low dielectric constant (Dk) of the cured product. Specifically, when molded into a 0.8 mm thick cured plate, the dielectric constant (Dk) at a frequency of 10 GHz measured according to the cavity resonator perturbation method is preferably less than 2.45. The lower limit of the dielectric constant (Dk) is not particularly specified, but a practical value is, for example, 0.01 or more. More specifically, the dielectric constant (Dk) of the cured plate is measured by the method described in the Examples below.

[0139] The resin composition of this embodiment is used as a layered material (including film and sheet forms) such as a prepreg or resin composite sheet that serves as an insulating layer for a printed wiring board. When used as such a layered material, the thickness is preferably 5 μm or more, more preferably 10 μm or more. The upper limit of the thickness is preferably 200 μm or less, more preferably 180 μm or less. Note that the thickness of the layered material refers to the thickness including the glass cloth, for example, when the resin composition of this embodiment is impregnated into glass cloth or the like. Materials formed from the resin composition of this embodiment may be used in applications where a pattern is formed by exposure and development, or in applications where exposure and development are not required. They are particularly suitable for applications where exposure and development are not required.

[0140] <<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., by impregnation and / or coating) and then semi-curing by heating (e.g., by drying at 120 to 220°C for 2 to 15 minutes). In this case, the amount of resin composition attached to the substrate, i.e., the amount of resin composition (including filler (G)) relative to the total amount of semi-cured prepreg, is preferably in the range of 20 to 99% by mass, more preferably in the range of 20 to 80% by mass.

[0141] The substrate is not particularly limited as long as it is a substrate used in various printed wiring board materials. Examples of the material of the substrate 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 examples include woven fabric, nonwoven fabric, roving, chopped strand mat, surfacing mat, etc. These substrates may be used alone or in combination of two or more. Among these substrates, from the viewpoint of dimensional stability, woven fabrics that have been subjected to an ultra-opening treatment and a clogging treatment are preferred. 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 / m ２ The following glass woven fabrics are preferred, and from the viewpoint of moisture absorption and heat resistance, glass woven fabrics that have been surface-treated with a silane coupling agent such as epoxy silane or amino silane are preferred. From the viewpoint of electrical properties, low-dielectric glass cloths made of glass fibers exhibiting a low relative dielectric constant and low dielectric dissipation factor, such as L-glass, NE-glass, NER-glass, and Q-glass, are more preferred. Examples of substrates with a low relative dielectric constant include substrates with a relative dielectric constant of 5.0 or less (preferably 3.0 to 4.9). Examples of substrates with a low dielectric dissipation factor include substrates with a dielectric dissipation factor of 0.006 or less (preferably 0.001 to 0.005). The relative dielectric constant and dielectric dissipation factor are values ​​measured at a frequency of 10 GHz using a perturbation method cavity resonator.

[0142] <<Metal Foil-Clad Laminate>> The metal foil-clad laminate of this embodiment includes at least one layer formed from the prepreg of this embodiment and a metal foil disposed on one or both sides of the layer formed from the prepreg. Examples of methods for producing the metal foil-clad laminate of this embodiment include a method in which at least one prepreg of this embodiment (preferably two or more prepregs) is disposed, and a metal foil is disposed on one or both sides of the prepreg, followed by laminate molding. More specifically, the laminate can be produced by disposing a metal foil, such as copper or aluminum, on one or both sides of the prepreg and then laminating the prepreg. The number of prepregs is preferably 1 to 10, more preferably 2 to 10, and even more preferably 2 to 9. The metal foil may be any foil suitable for use in printed wiring boards, including, but not limited to, copper foils such as rolled copper foil and electrolytic copper foil. The thickness of the metal foil (preferably, copper foil) is not particularly limited and may be approximately 1.5 to 70 μm. Furthermore, when copper foil is used as the metal foil, the copper foil preferably has a surface roughness Rz of 0.2 to 4.0 μm, as measured in accordance with JIS B0601:2013. By adjusting the surface roughness Rz to 0.2 μm or more, the copper foil surface roughness becomes appropriate, and the copper foil peel strength tends to be further improved. On the other hand, by adjusting the surface roughness Rz to 4.0 μm or less, the copper foil surface roughness becomes appropriate, and the dielectric loss tangent characteristics of the resulting cured product tend to be further improved. From the viewpoint of reducing the dielectric loss tangent, the surface roughness Rz of the copper foil is more preferably 0.5 μm or more, even more preferably 0.6 μm or more, particularly preferably 0.7 μm or more, and more preferably 3.5 μm or less, even more preferably 3.0 μm or less, and particularly preferably 2.0 μm or less.

[0143] Examples of lamination molding methods include methods commonly used for molding laminates and multilayer boards for printed wiring boards. More specifically, methods using a multistage press, multistage vacuum press, continuous molding machine, autoclave molding machine, or the like, are used at a temperature of about 180 to 350°C, a heating time of about 100 to 300 minutes, and a surface pressure of 20 to 100 kg / cm. ２Examples of suitable methods include lamination molding at a thickness of about 1000 μm. Furthermore, a multilayer board can also be produced by combining the prepreg of this embodiment with a separately prepared inner layer wiring board and laminating and molding it. As a method for producing a multilayer board, for example, copper foil of about 35 μm is placed on both sides of one prepreg of this embodiment, and the laminate is formed using the above-mentioned molding method. Then, an inner layer circuit is formed, and this circuit is blackened to form an inner layer circuit board. Then, this inner layer circuit board and the prepreg of this embodiment are alternately arranged one by one, and copper foil is placed on the outermost layer. The multilayer board can be produced by laminating and molding it under the above-mentioned conditions, preferably under vacuum. The metal foil-clad laminate of this embodiment can be suitably used as a printed wiring board.

[0144] The metal foil-clad laminate of this embodiment preferably has a peel strength of 0.28 kN / m or more, more preferably 0.38 kN / m or more, and even more preferably 0.50 kN / m or more, measured in accordance with the provisions of JIS C6481, 5.7 "Peel Strength." The upper limit of the peel strength is not particularly specified, but is, for example, 2.00 kN / m or more. The peel strength is measured according to the description of the examples described below.

[0145] As described above, the resin composition for electronic materials obtained using the resin composition of the present embodiment (a resin composition including a combination of specific components) can provide a cured product that has low dielectric properties (low dielectric constant, low dielectric dissipation factor, particularly low dielectric constant), moisture absorption heat resistance, peel strength against metal foil, as well as excellent properties such as heat resistance, desmear resistance, crack resistance, cured product appearance, and low thermal expansion.

[0146] <<Printed Wiring Board>> The printed wiring board of this embodiment includes an insulating layer and a conductor layer disposed on the surface of the insulating layer, wherein the insulating layer includes at least one of a layer formed from the resin composition of this embodiment and a layer formed from the prepreg of this embodiment. Such a printed wiring board can be manufactured using conventional methods, and the manufacturing method is not particularly limited. An example of a method for manufacturing a printed wiring board is described below. First, a metal foil-clad laminate, such as the copper foil-clad laminate described above, is prepared. Next, the surface of the metal foil-clad laminate is etched to form an inner layer circuit, thereby producing an inner layer substrate. If necessary, the surface of the inner layer circuit of this inner layer substrate is subjected to a surface treatment to increase adhesive strength. Next, a required number of the prepregs described above are stacked on the surface of the inner layer circuit, and metal foil for an outer layer circuit is further laminated on the outside, followed by heating and pressurizing to form an integral mold. In this way, a multilayer laminate is manufactured, in which an insulating layer composed of a substrate and a cured product of the resin composition is formed between the inner layer circuit and the metal foil for the outer layer circuit. Next, this multilayer laminate is subjected to drilling processing for through holes and via holes, and then a plated metal film is formed on the wall surface of the hole to provide electrical continuity between the inner layer circuit and the metal foil for the outer layer circuit.The metal foil for the outer layer circuit is then etched to form the outer layer circuit, thereby producing a printed wiring board.

[0147] The printed wiring board obtained in the above manufacturing example has an insulating layer and a conductor layer formed on the surface of this insulating layer, and the insulating layer contains the resin composition of the present embodiment described above and / or its cured product. That is, the prepreg of the present embodiment described above (for example, a prepreg formed from a base material and the resin composition of the present embodiment impregnated or applied thereto), or the layer formed from the resin composition of the metal foil-clad laminate of the present embodiment described above, serves as the insulating layer of the present embodiment. This embodiment also relates to a semiconductor device including the printed wiring board. For details of the semiconductor device, please refer to paragraphs 0200 to 0202 of JP 2021-021027 A, the contents of which are incorporated herein by reference.

[0148] Furthermore, it is preferable that the insulating layer formed from the cured product of the resin composition of this embodiment has a small surface roughness after roughening treatment. Specifically, the arithmetic mean roughness Ra of the surface of the insulating layer after roughening treatment is preferably 200 nm or less, more preferably 150 nm or less, and particularly preferably 100 nm or less. The lower limit of the arithmetic mean roughness Ra is not particularly limited, but may be, for example, 10 nm or more. The arithmetic mean roughness Ra of the surface of the insulating layer is measured using a non-contact surface roughness meter in VSI mode with a 50x magnification lens. The non-contact surface roughness meter used is a WYKONT3300 manufactured by Veeco Instruments.

[0149] <<Resin Composite Sheet>> The resin composite sheet of this embodiment includes a support and a layer formed from the resin composition of this embodiment and disposed on the surface of the support. The resin composite sheet can be used as a build-up film or a dry film solder resist. There are no particular limitations on the method for producing the resin composite sheet, but examples include a method of obtaining a resin composite sheet by applying (coating) a solution obtained by dissolving the resin composition of this embodiment in a solvent to a support and drying the applied solution.

[0150] Examples of the support used here include, but are not limited to, polyethylene film, polypropylene film, polycarbonate film, polyethylene terephthalate film, ethylene tetrafluoroethylene copolymer film, and release films obtained by applying a release agent to the surface of these films, organic film substrates such as polyimide film, conductive foils such as copper foil and aluminum foil, glass plates, SUS (Steel Use Stainless) plates, FRP (Fiber-Reinforced Plastics), and other plate-shaped materials.

[0151] Examples of application methods (coating methods) include methods in which a solution of the resin composition of this embodiment dissolved in a solvent is applied to a support using a bar coater, die coater, doctor blade, baker applicator, or the like. Furthermore, after drying, a single-layer sheet can be obtained by peeling or etching the support from a resin composite sheet in which the support and the resin composition are laminated. It should be noted that a single-layer sheet can also be obtained without using a support by supplying a solution of the resin composition of this embodiment dissolved in a solvent into a mold having a sheet-shaped cavity and drying it to form it into a sheet.

[0152] In the production of the monolayer sheet or resin composite sheet of this embodiment, the drying conditions for removing the solvent are not particularly limited. However, because low temperatures tend to leave the solvent in the resin composition, and high temperatures accelerate curing of the resin composition, drying conditions of 20°C to 200°C for 1 to 90 minutes are preferred. The monolayer sheet or resin composite sheet can be used in an uncured state after the solvent has been dried, or it can be used in a semi-cured (B-staged) state as needed. Furthermore, the thickness of the resin layer in the monolayer sheet or resin composite sheet of this embodiment can be adjusted by the concentration and coating thickness of the solution of the resin composition of this embodiment used for coating (coating). While not particularly limited, a thickness of 0.1 to 500 μm is preferred because a thicker coating thickness generally leads to more solvent remaining during drying.

[0153] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing 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 used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

[0154] <Measurement of Weight-Average Molecular Weight and Number-Average Molecular Weight> The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the resin component were measured by gel permeation chromatography (GPC) using a liquid pump (Shimadzu Corporation, LC-20AD), a differential refractive index detector (Shimadzu Corporation, RID-10A), and GPC columns (Showa Denko K.K., GPC KF-801, 802, 803, 804), with tetrahydrofuran as the solvent, a flow rate of 1.0 mL / min, a column temperature of 40°C, and a calibration curve based on monodisperse polystyrene.

[0155] <Measurement of relative dielectric constant of resin component> The resin component was powdered, and the obtained powder was filled into a mold with a side of 100 mm and a thickness of 0.8 mm. Copper foil (3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) with a thickness of 12 μm was placed on both sides, and a pressure of 30 kg / cm was applied. ２ The cured resin was vacuum-pressed at 220°C for 120 minutes to obtain a cured plate with a side length of 100 mm and a thickness of 0.8 mm. The dielectric constant (Dk) was evaluated as follows. The copper foil on both sides of the cured resin was removed by etching, and the plate was then downsized to 10 mm x 1 mm to obtain an evaluation sample. The evaluation sample was dried at 120°C for 60 minutes, and then the dielectric constant (Dk) after drying was measured at a frequency of 10 GHz using a perturbation cavity resonator. The measurement temperature was 23°C. The perturbation cavity resonator used was an Agilent 8722ES manufactured by Agilent Technologies. The evaluation results are shown in Table 1. However, for the dielectric constant of the block copolymer (C) having a styrene skeleton or a resin that could not be cured by the vacuum pressing, the resin was dried in pellet form at 120°C for 60 minutes, and then the dielectric constant (Dk) after drying was measured at a frequency of 10 GHz using a perturbation cavity resonator. The measurement temperature was 23°C.

[0156] Synthesis Example 1: Synthesis of polymer (va) having structural units represented by formula (V) 2.25 moles (292.9 g) of divinylbenzene, 1.32 moles (172.0 g) of ethylvinylbenzene, 11.43 moles (1190.3 g) of styrene, and 15.0 moles (1532.0 g) of n-propyl acetate were charged into a reactor, and 600 mmol of a boron trifluoride diethyl ether complex was added at 70°C, followed by a reaction for 4 hours. The polymerization reaction was terminated with an aqueous sodium bicarbonate solution, and the oil layer was washed three times with pure water. The mixture was then subjected to reduced pressure devolatilization at 60°C, and polymer (va) having structural units represented by formula (V) was recovered. The obtained polymer (va) having structural units represented by formula (V) was weighed, and it was confirmed that 860.8 g of polymer (va) having structural units represented by formula (V) was obtained.

[0157] The resulting polymer (va) having a structural unit represented by formula (V) had a number average molecular weight Mn of 2,060, a weight average molecular weight Mw of 30,700, and a monodispersity index Mw / Mn of 14.9. １３ C-NMR and １ By performing H-NMR analysis, resonance lines derived from each monomer unit used as a raw material were observed in polymer (va) having a structural unit represented by formula (V). Based on the NMR measurement results and GC analysis results, the proportions of each monomer unit (structural unit derived from each raw material) in polymer (va) having a structural unit represented by formula (V) were calculated as follows: structural units derived from divinylbenzene: 20.9 mol% (24.3 mass%), structural units derived from ethylvinylbenzene: 9.1 mol% (10.7 mass%), structural units derived from styrene: 70.0 mol% (65.0 mass%), and the proportion of structural units having a residual vinyl group derived from divinylbenzene was 16.7 mol% (18.5 mass%). The relative dielectric constant measured according to the above method was 2.3.

[0158] Synthesis Example 2: Synthesis of modified polyphenylene ether compound Synthesis of bifunctional phenylene ether oligomer A 12 L vertical reactor equipped with a stirrer, a thermometer, an air inlet tube, and a baffle plate was charged with CuBr. ２9.36 g (42.1 mmol), 1.81 g (10.5 mmol) of N,N'-di-t-butylethylenediamine, 67.77 g (671.0 mmol) of n-butyldimethylamine, and 2,600 g of toluene were charged, and the mixture was stirred at a reaction temperature of 40°C. 129 g of 2,2',3,3',5,5'-hexamethyl-(1,1'-biphenol)-4,4'-diol, which had been dissolved in advance in 2,300 g of methanol, was added. A mixed solution of 32 g (0.48 mol), 878.4 g (7.2 mol) of 2,6-dimethylphenol, 1.22 g (7.2 mmol) of N,N'-di-t-butylethylenediamine, and 26.35 g (260.9 mmol) of n-butyldimethylamine was added dropwise over 230 minutes while bubbling a mixed gas of nitrogen and air adjusted to an oxygen concentration of 8% by volume at a flow rate of 5.2 L / min and stirring was continued. After completion of the dropwise addition, 1,500 g of water containing 48.06 g (126.4 mmol) of tetrasodium ethylenediaminetetraacetate was added to terminate the reaction. The aqueous and organic layers were separated, and the organic layer was washed with a 1N aqueous hydrochloric acid solution and then with pure water. The resulting solution was concentrated to 50% by mass using an evaporator, yielding 1,981 g of a toluene solution of a bifunctional phenylene ether oligomer (Resin "A"). Resin "A" had a number average molecular weight of 1,975 as converted into polystyrene by the GPC method, a weight average molecular weight of 3,514 as converted into polystyrene by the GPC method, and a hydroxyl equivalent of 990.

[0159] <<Synthesis of Modified Polyphenylene Ether Compound>> A reactor equipped with a stirrer, thermometer, and reflux condenser was charged with 833.4 g of a toluene solution of resin "A," 76.7 g of vinylbenzyl chloride (AGC Seimi Chemical Co., Ltd., "CMS-P"), 1,600 g of methylene chloride, 6.2 g of benzyldimethylamine, 199.5 g of pure water, and 83.6 g of a 30.5% by mass aqueous NaOH solution, and the mixture was stirred at a reaction temperature of 40°C. After stirring for 24 hours, the organic layer was washed with a 1N aqueous hydrochloric acid solution and then with pure water. The resulting solution was concentrated using an evaporator and added dropwise to methanol to solidify. The solid was recovered by filtration and dried in vacuo to obtain 450.1 g of a modified polyphenylene ether compound. The modified polyphenylene ether compound had a polystyrene-equivalent number average molecular weight of 2,250 as measured by GPC, a polystyrene-equivalent weight average molecular weight of 3,920 as measured by GPC, and a vinyl group equivalent of 1,189 g / vinyl group. The dielectric constant measured according to the above method was 2.4.

[0160] Synthesis Example 3: Synthesis of naphthol aralkyl cyanate ester compound (SNCN) 300 g (1.28 mol in terms of OH groups) of 1-naphthol aralkyl resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) and 194.6 g (1.92 mol) of triethylamine (1.5 mol per mol of hydroxy groups) were dissolved in 1,800 g of dichloromethane, and the resulting solution was designated Solution 1. 125.9 g (2.05 mol) of cyanogen chloride (1.6 mol per mol of hydroxy groups), 293.8 g of dichloromethane, 194.5 g (1.92 mol) of 36% hydrochloric acid (1.5 mol per mol of hydroxy groups), and 1,205.9 g of water were stirred, and Solution 1 was added over 30 minutes while maintaining the liquid temperature between −2° C. and −0.5° C. After the addition of Solution 1 was completed, the mixture was stirred at the same temperature for 30 minutes, and then a solution (Solution 2) prepared by dissolving 65 g (0.64 mol) of triethylamine (0.5 mol per mol of hydroxyl groups) in 65 g of dichloromethane was added over 10 minutes. After the addition of Solution 2 was completed, the mixture was stirred at the same temperature for 30 minutes to complete the reaction. The reaction solution was then allowed to stand, and the organic and aqueous phases were separated. The resulting organic phase was washed five times with 1,300 g of water. The electrical conductivity of the wastewater from the fifth water wash was 5 μS / cm, confirming that the ionic compounds were sufficiently removed by washing with water. The organic phase after water washing was concentrated under reduced pressure and finally concentrated to dryness at 90°C for 1 hour, yielding 331 g of the desired naphthol aralkyl cyanate ester compound (SNCN) (orange viscous substance). The weight-average molecular weight of the resulting SNCN was 600. The IR spectrum of SNCN measured at 2250 cm －１ The dielectric constant measured according to the above method was 2.8.

[0161] Example 1 14.0 parts by mass of a maleimide compound (ma) shown in the structure below (a compound represented by formula (3), manufactured by Designer Molecules Inc., "BMI-5000," having a weight-average molecular weight of 17,000 and a dielectric constant measured according to the method described above of 2.3), 19.0 parts by mass of a maleimide compound (mb) shown in the structure below (manufactured by DIC Corporation, "NE-X-9470S," a compound represented by formula (M1), having a weight-average molecular weight of 2,500 and a dielectric constant measured according to the method described above of 2.4), and 15.0 parts by mass of a block copolymer (SBS, manufactured by JSR Corporation, TR2250, having a weight-average molecular weight of 120,000 and a dielectric constant measured according to the method described above of 2.1). A varnish was obtained by dissolving and mixing the following in methyl ethyl ketone (solvent): 5.0 parts by mass of the polymer (va) having a structural unit represented by formula (V) obtained in Synthesis Example 1 above, 19.0 parts by mass of the modified polyphenylene ether compound obtained in Synthesis Example 2 above, 5.0 parts by mass of the naphthol aralkyl cyanate ester compound (SNCN) obtained in Synthesis Example 3 above, 3.0 parts by mass of 4-methylstyrene (Tokyo Chemical Industry Co., Ltd.), 20.0 parts by mass of a phosphorus-based flame retardant (PX-200, Daihachi Chemical Industry Co., Ltd.), and 0.25 parts by mass of an imidazole-based catalyst (Shikoku Chemical Industry Co., Ltd.). Note that the amounts added above indicate solid content amounts.

[0162] Maleimide compound (ma) The maleimide compound (ma) is a compound represented by the formula (3), １ and R ３ is an octylene group, and R ２ is a cyclohexylene group having an n-hexyl group and an n-octyl group as substituents, and is a compound having a weight average molecular weight of 17,000.

[0163] Maleimide compound (mb) n is an integer from 1 to 20.

[0164] <Production of 0.8 mm thick cured plate test piece> The solvent was evaporated and distilled off from the obtained varnish to obtain a resin composition powder. The resin composition powder was filled into a mold with a side of 100 mm and a thickness of 0.8 mm, and 12 μm thick copper foil (3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on both sides, and a pressure of 30 kg / cm was applied. ２The cured sheet was then vacuum pressed at 220°C for 120 minutes to obtain a cured plate having a side length of 100 mm and a thickness of 0.8 mm. The resulting cured plate was evaluated for dielectric constant (Dk), peel strength, and moisture absorption heat resistance. The evaluation results are shown in Table 1.

[0165] <Measurement and Evaluation Methods> (1) Relative Dielectric Constant (Dk) After removing the copper foil on both sides of the obtained cured sheet by etching, the sheet was downsized to 10 mm x 1 mm to obtain an evaluation sample. The obtained evaluation sample was dried at 120°C for 60 minutes, and then the relative dielectric constant (Dk) after drying at a frequency of 10 GHz was measured using a perturbation method cavity resonator. The measurement temperature was 23°C. The perturbation method cavity resonator used was an Agilent 8722ES manufactured by Agilent Technologies. A: Less than 2.45 B: 2.45 or more

[0166] (2) Peel Strength Using the cured sheet (10 mm x 100 mm x 0.8 mm) obtained as described above, the copper foil peel strength (adhesion strength) was measured twice in accordance with the provisions of JIS C6481, 5.7 "Peel Strength", and the average value was calculated. The measurement temperature was 23°C. The evaluation was as follows: A: 0.4 kN / m or more B: Less than 0.4 kN / m

[0167] (3) Moisture absorption heat resistance The obtained cured plate was cut (downsized) to 50 mm x 50 mm, and all of the copper foil on one side was removed by etching. On the other side, half of the copper foil was removed by etching to obtain a sample for measuring moisture absorption heat resistance. The obtained sample was dried at 120 ° C for 60 minutes, and then left to stand for 5 hours in the presence of saturated steam at 121 ° C and 2 atmospheres using a pressure cooker tester. It was then immersed (dipped) in a solder bath at 260 ° C for 30 seconds, and the presence or absence of abnormal changes in appearance was visually observed. The pressure cooker tester used was a PC-3 model manufactured by Hirayama Seisakusho Co., Ltd. Each measurement was performed on three sheets, and if there was no swelling among the three sheets, it was rated as "A", and if swelling was observed, it was rated as "B". The appearance was observed by a majority vote of five experts.

[0168] Example 2 The same procedure was carried out as in Example 1, except that the contents of the maleimide compound (ma) were 10.5 parts by mass, the maleimide compound (mb) were 15.5 parts by mass, the polymer (va) having a structural unit represented by formula (V) was 15.5 parts by mass, and the modified polyphenylene ether compound was 15.5 parts by mass.

[0169] Example 3 The same procedures were carried out as in Example 1, except that the maleimide compound (ma) was not included, the content of the maleimide compound (a compound represented by formula (3), manufactured by Shin-Etsu Chemical Co., Ltd., "SLK-3000", having a relative dielectric constant of 2.3 as measured according to the above method, and having the same structure as the maleimide compound (ma) except for the value of n) was 10.5 parts by mass, the content of the maleimide compound (mb) was 15.5 parts by mass, the content of the polymer (va) having a structural unit represented by formula (V) was 15.5 parts by mass, and the content of the modified polyphenylene ether compound was 15.5 parts by mass.

[0170] Comparative Example 1 The same procedure was carried out as in Example 1, except that the maleimide compound (ma) was not included and the content of the polymer (va) having a structural unit represented by formula (V) was changed to 19.0 parts by mass.

[0171] Comparative Example 2 The same procedure was carried out as in Example 1, except that the content of the maleimide compound (ma) was 19.0 parts by mass, the content of the polymer (va) not containing the maleimide compound (mb) and having a structural unit represented by formula (V) was 19.0 parts by mass.

[0172] Comparative Example 3 The same procedure was carried out as in Example 1, except that the content of the maleimide compound (ma) was 19.0 parts by mass, the content of the maleimide compound (mb) was 24.0 parts by mass, the content of the polymer (va) which did not contain a block copolymer and had a structural unit represented by formula (V) was 10.0 parts by mass, and the content of the modified polyphenylene ether compound was 24.0 parts by mass.

[0173] Comparative Example 4 The same procedure was carried out as in Example 1, except that the content of the maleimide compound (ma) was 27.0 parts by mass, the content of the maleimide compound (mb) was 30.0 parts by mass, and the polymer (va) having a structural unit represented by formula (V) and the modified polyphenylene ether compound were not contained.

[0174] Comparative Example 5 The same procedure as in Example 1 was repeated, except that the maleimide compound (mb) was not included and the content of the maleimide compound (mc) shown in the structure below (manufactured by Nippon Kayaku Co., Ltd., MIR-3000, relative dielectric constant measured according to the above method is 2.7) was changed to 19.0 parts by mass.

[0175] Comparative Example 6 The same procedure as in Example 1 was repeated, except that the maleimide compound (mb) was not included and the content of the maleimide compound (md) shown in the structure below (manufactured by Daiwa Chemical Industry Co., Ltd., BMI-2300, relative dielectric constant measured according to the above method is 2.9) was changed to 19.0 parts by mass.

[0176]