resin composition

Abstract

To provide a resin composition with excellent varnish stability. [Solution] A resin composition comprising (A) epoxy resin, (B) maleimide resin, a specific range of amounts of (C) inorganic filler, and a specific (D) cyclic phosphazene compound.

Description

[Technical Field]

[0001] The present invention relates to resin compositions and their cured products, resin sheets, circuit boards, and semiconductor devices. [Background technology]

[0002] Circuit boards, such as printed circuit boards, are widely used in various electronic devices. A known manufacturing method for circuit boards involves a build-up method in which insulating layers and conductive layers are alternately stacked on an inner layer substrate. The insulating layer is formed, for example, by a cured product of a resin composition containing a curable resin such as epoxy resin. To improve flame retardancy, resin compositions containing flame retardants are sometimes used (see Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-21767 [Patent Document 2] Japanese Patent Publication No. 2021-04297 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Generally, resin compositions are sometimes stored in the form of a resin varnish, which is a liquid composition containing a solvent. Unless otherwise specified, the term "varnish stability" refers to the property of a resin composition that exhibits minimal precipitation of its components when stored in the form of a resin varnish.

[0005] Furthermore, when an insulating layer is formed using a cured resin composition, the insulating layer is required to maintain its insulating properties even under harsh environmental conditions. Therefore, high insulating reliability is desirable for the cured material.

[0006] Furthermore, it is desirable for the cured product of the resin composition to have a low dielectric loss tangent from the viewpoint of obtaining an insulating layer that can reduce transmission loss. From the viewpoint of obtaining such a low dielectric loss tangent, resin compositions containing a large amount of inorganic filler are sometimes used. However, conventionally, it has been difficult to obtain a resin composition that has excellent varnish stability and a cured product that has excellent insulating reliability and dielectric loss tangent by combining epoxy resin, inorganic filler, and flame retardant.

[0007] The present invention was devised in view of the above-mentioned problems, and aims to provide a resin composition that has excellent varnish stability and yields a cured product with excellent insulation reliability and dielectric loss tangent; a resin sheet containing the resin composition; a cured product of the resin composition; a circuit board containing the cured product of the resin composition; and a semiconductor device containing the circuit board. [Means for solving the problem]

[0008] The inventors diligently studied to solve the aforementioned problems. As a result, the inventors found that a resin composition comprising (A) epoxy resin, (B) maleimide resin, a specific range of amounts of (C) inorganic filler, and a specific (D) cyclic phosphazene compound can solve the aforementioned problems, and thus completed the present invention. In other words, the present invention includes the following:

[0009] <1> A resin composition comprising (A) epoxy resin, (B) maleimide resin, (C) inorganic filler, and (D) a cyclic phosphazene compound represented by the following formula (1), (C) A resin composition in which the amount of inorganic filler is 60% by mass or more relative to 100% by mass of the nonvolatile components of the resin composition. [ka] (In equation (1), R 1 and R 2 teeth, (i) Each independently, Nitro group, Alkyl or alkoxy groups having 1 to 8 carbon atoms, which may be substituted with at least one group selected from the group consisting of alkyl and aryl groups having 1 to 6 carbon atoms, An aryl group or aryloxy group having 6 to 20 carbon atoms may be substituted with at least one group selected from the group consisting of alkyl groups and aryl groups having 1 to 6 carbon atoms. It represents one of the following, or (ii) A saturated or unsaturated cyclic structure which may be substituted with an alkyl or carbonyl group having 1 to 6 carbon atoms; L represents a divalent heteroatom; a and b each represent integers from 0 to 4 independently; Each m independently represents either 0 or 1; n represents an integer from 3 to 8; The structure of each repeating unit is independent. <2> The ratio of (B) maleimide resin to (A) epoxy resin ((B) maleimide resin / (A) epoxy resin) is 0.01 or more and 2.0 or less by mass. <1> The resin composition described above. <3> The ratio of (B) maleimide resin to (A) epoxy resin ((B) maleimide resin / (A) epoxy resin) is less than 0.6 by mass. <2> The resin composition described above. <4> (A) The amount of epoxy resin is 1% by mass or more and 30% by mass or less, relative to 100% by mass of the nonvolatile components of the resin composition. <1> ~ <3> A resin composition according to any one of the items. <5> (B) The amount of maleimide resin is 0.1% by mass or more and 20% by mass or less, relative to 100% by mass of the nonvolatile components of the resin composition. <1> ~ <4> A resin composition according to any one of the items. <6> (C) The amount of inorganic filler is 90% by mass or less relative to 100% by mass of the non-volatile components of the resin composition. <1> ~ <5> A resin composition according to any one of the items. <7> (D) The amount of the cyclic phosphazene compound is 0.1% by mass or more and 5% by mass or less, relative to 100% by mass of the nonvolatile components of the resin composition. <1> ~ <6> A resin composition according to any one of the items. <8> (D) The amount of the cyclic phosphazene compound is 0.01% by mass or more and 5% by mass or less, relative to 100% by mass of the inorganic filler. <1> ~ <7> A resin composition according to any one of the items. <9> (D) The cyclic phosphazene compound is a particle having an average particle diameter of 1.5 μm or less. <1> ~ <8> A resin composition according to any one of the items. <10> (D) The cyclic phosphazene compound is a particle having an average particle diameter of 0.8 μm or less. <1> ~ <9> A resin composition according to any one of the items. <11> (D) Does not contain any cyclic phosphazene compounds other than component (D), <1> ~ <10> A resin composition according to any one of the items. <12> The resin composition is not fibrous. <1> ~ <11> A resin composition according to any one of the items. <13> (D) Cyclic phosphazene compounds are D a These are particles with an average particle diameter of μm. (C) The average particle size of the inorganic filler is D b It is μm, D a / D b However, it is between 0.1 and 10. <1> ~ <12> A resin composition according to any one of the items. <14> D a / D b However, it is 1.5 or less. <13> The resin composition described above. <15> (D) A cyclic phosphazene compound having a melting point of 260°C or higher, <1> ~ <14> A resin composition according to any one of the items. <16> (D) When a first dissolution test was performed in which the cyclic phosphazene compound was dissolved in 10 g of cyclohexanone by sonication at 25°C for 10 minutes, the amount of cyclic phosphazene compound dissolved was 0.04 g or less. <1> ~ <15> A resin composition according to any one of the items. <17> (D) When a second dissolution test was performed in which the cyclic phosphazene compound was dissolved in 10 g of cyclohexanone by sonication at 70°C for 10 minutes, the amount of cyclic phosphazene compound dissolved was 0.3 g or less. <1> ~ <16> A resin composition according to any one of the items. <18> The resin composition contains a ketone-based solvent. <1> ~ <17> A resin composition according to any one of the items. <19> The resin composition contains (J) solvent, (J) The solvent includes a non-aromatic high-boiling point solvent that does not contain an aromatic ring in its molecule and has a boiling point of 100°C or higher. <1> ~ <18> A resin composition according to any one of the items. <20> (J-1) The amount of non-aromatic high-boiling point solvent is 20% by mass or less relative to 100% by mass of the total amount of solvent (J). <19> The resin composition described above. <21> (J-1) The amount of non-aromatic high-boiling point solvent is 4.8% by mass or less based on 100% by mass of the total amount of the resin composition. <19> or <20> The resin composition described above. <22> (B) Maleimide resin includes aromatic maleimide resin, <1> ~ <21> A resin composition according to any one of the items. <23> A support and a resin composition layer formed on the support, The resin composition layer <1> ~ <22> A resin sheet comprising the resin composition described in any one of the items. <24> <1> ~ <22> A cured product of the resin composition described in any one of the items. <25> <1> ~ <22> A circuit board comprising a cured product of the resin composition described in any one of the items. <26> <25> A semiconductor device including the circuit board described above. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a resin composition that has excellent varnish stability and yields a cured product with excellent insulation reliability and dielectric loss tangent; a resin sheet containing the resin composition; a cured product of the resin composition; a circuit board containing the cured product of the resin composition; and a semiconductor device containing the circuit board.

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments and exemplifications of the present invention will be described. However, the present invention is not limited to the embodiments and exemplifications shown below, and may be modified and implemented within the scope not departing from the claims and their equivalent scope.

[0012] In this specification, unless otherwise specified, the term "may be substituted" for a compound, group or ring by a substituent means both the case where the hydrogen atom of the compound, group or ring is not substituted by a substituent and the case where some or all of the hydrogen atoms of the compound, group or ring are substituted by a substituent.

[0013] In this specification, unless otherwise specified, the term "resin composition layer" represents a layer containing a resin composition. Usually, the resin composition layer contains only the resin composition.

[0014] In this specification, unless otherwise specified, the term "cured product layer" represents a layer containing a cured product of a resin composition. Usually, the cured product layer contains only the cured product of the resin composition.

[0015] [[ID=2O]] <Overview of Resin Composition> The resin composition according to an embodiment of the present invention contains (A) an epoxy resin, (B) a maleimide resin, (C) an inorganic filler in a specific range, and (D) a cyclic phosphazene compound represented by the following formula (1).

[0016] [Chemical Formula]

[0017] (In formula (1), R [[ID=H]] 1 and R 2 are (i) Each independently, a nitro group, Alkyl or alkoxy groups having 1 to 8 carbon atoms, which may be substituted with at least one group selected from the group consisting of alkyl and aryl groups having 1 to 6 carbon atoms, An aryl group or aryloxy group having 6 to 20 carbon atoms may be substituted with at least one group selected from the group consisting of alkyl groups and aryl groups having 1 to 6 carbon atoms. It represents one of the following, or (ii) A saturated or unsaturated cyclic structure which may be substituted with an alkyl or carbonyl group having 1 to 6 carbon atoms; L represents a divalent heteroatom; a and b each represent integers from 0 to 4 independently; Each m independently represents either 0 or 1; n represents an integer from 3 to 8; The structure of each repeating unit is independent.

[0018] In the following explanation, the repeating unit represented by formula (2) below may be referred to as a "phosphazene unit".

[0019] [ka]

[0020] (The symbol R in equation (2)) 1 , R 2 L, a, b, and m are equivalent to those in equation (1).

[0021] The resin composition according to this embodiment can have excellent varnish stability. Furthermore, the resin composition according to this embodiment can produce a cured product with excellent insulation reliability and dielectric loss tangent. In addition, the cured product of the resin composition according to this embodiment can usually have a high glass transition temperature. Furthermore, the cured product of the resin composition according to this embodiment can usually have low surface roughness after roughening treatment. Furthermore, the cured product of the resin composition according to this embodiment can usually achieve high adhesion to the conductive layer.

[0022] <(A) Epoxy resin> The resin composition according to this embodiment includes an epoxy resin (A) as component (A). The epoxy resin (A) may be a curable resin having epoxy groups. The epoxy resins (A) may react with each other to cure the resin composition. Alternatively, the epoxy resin (A) may react with a maleimide resin (B) in the presence of a catalyst such as an imidazole compound to cure the resin composition. Furthermore, the epoxy resin (A) may react with any curing agent described later to cure the resin composition. The epoxy resin (A) may be used alone or in combination of two or more types.

[0023] (A) Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol C type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolac type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, phenol aralkyl type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiroring-containing epoxy resin, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, naphthylene ether type epoxy resin, trimethylol type epoxy resin, tetraphenylethane type epoxy resin, isocyanurate type epoxy resin, phenolphthaleimidine type epoxy resin, and the like. Biphenyl-type epoxy resins refer to epoxy resins having a biphenyl structure, where the biphenyl structure may have substituents such as alkyl groups, alkoxy groups, or aryl groups. Therefore, bixylenol-type epoxy resins and biphenylaralkyl-type epoxy resins can be included in the category of biphenyl-type epoxy resins.

[0024] (A) From the viewpoint of obtaining a cured product with excellent heat resistance, the epoxy resin preferably contains an epoxy resin containing an aromatic structure. An aromatic structure is a chemical structure generally defined as aromatic, and includes polycyclic aromatics and aromatic heterocyclics. Examples of epoxy resins containing an aromatic structure include bisphenol A type epoxy resin, bisphenol C type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolac type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, bisquilenol type epoxy resin, and glycidylamine having an aromatic structure. Examples include epoxy resins of the type glycidyl ester type having an aromatic structure, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin having an aromatic structure, epoxy resin having a butadiene structure having an aromatic structure, alicyclic epoxy resin having an aromatic structure, heterocyclic epoxy resin, spiro ring-containing epoxy resin having an aromatic structure, cyclohexanedimethanol type epoxy resin having an aromatic structure, naphthylene ether type epoxy resin, trimethylol type epoxy resin having an aromatic structure, and tetraphenylethane type epoxy resin having an aromatic structure.

[0025] Among these, bisphenol A type epoxy resin, bisphenol C type epoxy resin, bisphenol F type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, naphthylene ether type epoxy resin, phenolphthaleimidine type epoxy resin, and bixylenol type epoxy resin are preferred.

[0026] (A) The epoxy resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. (A) The proportion of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, relative to 100% by mass of the nonvolatile component of the epoxy resin.

[0027] (A) Epoxy resins include epoxy resins that are liquid at 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at 20°C (hereinafter sometimes referred to as "solid epoxy resins"). (A) Epoxy resins may contain only liquid epoxy resins, only solid epoxy resins, or a combination of liquid epoxy resins and solid epoxy resins.

[0028] Preferably, the liquid epoxy resin is one having two or more epoxy groups in one molecule. Preferred liquid epoxy resins include bisphenol A type epoxy resin, bisphenol C type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, and epoxy resin having a butadiene structure; more preferably, bisphenol A type epoxy resin, bisphenol C type epoxy resin, bisphenol F type epoxy resin, and naphthalene type epoxy resin.

[0029] Specific examples of liquid epoxy resins include DIC's "HP-4032," "HP-4032-D," and "HP-4032-SS" (naphthalene-type epoxy resin); Mitsubishi Chemical's "828US," "828EL," "jER828," "jER828EL," "825," and "Epicote 828EL" (bisphenol A-type epoxy resin); Mitsubishi Chemical's "jER807" and "1750" (bisphenol F-type epoxy resin); Mitsubishi Chemical's "jER152" (phenol novolac-type epoxy resin); Mitsubishi Chemical's "630," "630LSD," and "604" (glycidylamine-type epoxy resin); ADEKA's "ED-523T" (glycyrol-type epoxy resin); ADEKA's "EP-3950L" and "EP-3980S" (glycidylamine-type epoxy resin) Examples include xylose resins; "EP-4088S" (dicyclopentadiene type epoxy resin) manufactured by ADEKA Corporation; "ED-506" (polypropylene glycol type epoxy resin) manufactured by ADEKA Corporation; "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX Corporation; "Celoxide 2021P" (alicyclic epoxy resin with an ester skeleton) manufactured by Daicel Corporation; "PB-3600" manufactured by Daicel Corporation; "JP-100" and "JP-200" (epoxy resins with a butadiene structure) manufactured by Nippon Soda Co., Ltd.; and "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd. In addition, epoxy resins represented by formula (1) described in Japanese Patent Application Publication No. 2024-85315 may be used.

[0030] As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferred, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferred. As the solid epoxy resin, bixylenol type epoxy resin, naphthalene type epoxy resin, naphthalene type tetrafunctional epoxy resin, naphthol novolac type epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, naphthylene ether type epoxy resin, anthracene type epoxy resin, bisphenol A type epoxy resin, bisphenol AF type epoxy resin, phenol aralkyl type epoxy resin, tetraphenylethane type epoxy resin, and phenolphthaleimidine type epoxy resin are more preferred; biphenyl type epoxy resin, naphthalene type epoxy resin, naphthylene ether type epoxy resin, bixylenol type epoxy resin, dicyclopentadiene type epoxy resin, and phenolphthaleimidine type epoxy resin are even more preferred.

[0031] Specific examples of solid epoxy resins include DIC's "HP4032H" (naphthalene-type epoxy resin); DIC's "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resins); DIC's "N-690" (cresol novolac-type epoxy resin); DIC's "N-695" (cresol novolac-type epoxy resin); DIC's "HP-7200", "HP-7200HH", "HP-7200H", and "HP-7200L" (dicyclopentadiene-type epoxy resins); DIC's "EXA-7311" and "EXA-7 "311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP-6000", "HP-6000L" (naphthylene ether type epoxy resin); "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "ESN475V", "ESN410" manufactured by Nippon Steel Chemical & Material Co., Ltd. 0V, "ESN-4100VEK75" (naphthalene-type epoxy resin); "ESN485" (naphthol-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN375" (dihydroxynaphthalene-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YX4000HK", "YL7890" (bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL6121" (biphenyl-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; Mitsubishi Chemical Examples include "YX7700" (phenol aralkyl type epoxy resin) from CAL Corporation; "PG-100" and "CG-500" from Osaka Gas Chemical Co., Ltd.; "YX7760" (bisphenol AF type epoxy resin) from Mitsubishi Chemical Corporation; "YL7800" (fluorene type epoxy resin) from Mitsubishi Chemical Corporation; "jER1010" (bisphenol A type epoxy resin) from Mitsubishi Chemical Corporation; "jER1031S" (tetraphenylethane type epoxy resin) from Mitsubishi Chemical Corporation; and "WHR991S" (phenolphthalein type epoxy resin) from Nippon Kayaku Co., Ltd.

[0032] (A) When the epoxy resin contains a combination of liquid epoxy resin and solid epoxy resin, the mass ratio of the liquid epoxy resin to the solid epoxy resin is preferably 20:1 to 1:20, more preferably 10:1 to 1:10, and particularly preferably 7:1 to 1:7.

[0033] (A) The epoxy equivalent range of the epoxy resin is preferably 50 g / eq. to 5,000 g / eq., more preferably 60 g / eq. to 3,000 g / eq., even more preferably 80 g / eq. to 2,000 g / eq., and particularly preferably 110 g / eq. to 1,000 g / eq. Epoxy equivalent represents the mass of resin per equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0034] (A) The weight-average molecular weight (Mw) of the epoxy resin is preferably in the range of 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The weight-average molecular weight can be measured as a polystyrene equivalent by gel permeation chromatography (GPC).

[0035] (A) The amount of epoxy resin is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 5% by mass or more, preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition. Unless otherwise specified, the nonvolatile components of the resin composition refer to the components of the resin composition excluding (J) the solvent. When the amount of (A) epoxy resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and the glass transition temperature, surface roughness and adhesion of the cured product can usually be made particularly good.

[0036] (A) The amount of epoxy resin is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, based on 100% by mass of the resin components of the resin composition. Unless otherwise specified, the resin components of the resin composition refer to the non-volatile components of the resin composition excluding (C) inorganic fillers. When the amount of epoxy resin (A) is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and furthermore, the glass transition temperature, surface roughness and adhesion of the cured product can usually be made particularly good.

[0037] (B) Maleimide resin The resin composition according to this embodiment includes a maleimide resin (B) as component (B). The maleimide resin (B) represents a resin containing one or more, preferably two or more, maleimide groups (2,5-dihydro-2,5-dioxo-1H-pyrrole-1-yl groups) per molecule. The maleimide resin (B) can undergo radical polymerization reactions with other maleimide resins or with any radical polymerizable resin. Furthermore, the maleimide resin (B) can react with the epoxy resin (A) in the presence of a catalyst such as an imidazole compound. Therefore, the maleimide resin (B) can function as a curable resin that hardens the resin composition through reaction. The maleimide resin (B) may be used alone or in combination of two or more types.

[0038] Examples of (B) maleimide resins include (B-1) aromatic maleimide resins having maleimide groups directly bonded to aromatic rings, and (B-2) aliphatic maleimide resins having maleimide groups directly bonded to aliphatic groups. The maleimide resin may contain only (B-1) aromatic maleimide resin, only (B-2) aliphatic maleimide resin, or a combination of (B-1) aromatic maleimide resin and (B-2) aliphatic maleimide resin. In particular, it is preferable that the (B) maleimide resin contains (B-1) aromatic maleimide resin.

[0039] Furthermore, (B) the maleimide resin is preferably one that contains a specific molecular skeleton. A preferred molecular skeleton is, for example, an alicyclic skeleton. Among alicyclic skeletons, maleimide resins containing an indan skeleton are particularly preferred.

[0040] (B) A preferred example of a maleimide resin is a maleimide resin containing a substructure represented by the following formula (B1). Typically, a maleimide resin containing a substructure represented by formula (B1) is an (B-2) aliphatic maleimide resin. Furthermore, the number of maleimide groups in one molecule of a maleimide resin containing a substructure represented by formula (B1) is preferably two or more, and more preferably two.

[0041] [ka]

[0042] (In equation (B1), ring B b This represents an aliphatic hydrocarbon ring which may have substituents; i b and j b Each of these independently represents an integer of 0 or 1 or greater, and i b and j b The sum of the values ​​is 6 or more; * indicates a binding site.

[0043] In equation (B1), ring B b represents an aliphatic hydrocarbon ring which may have substituents. The aliphatic hydrocarbon ring may be a saturated aliphatic hydrocarbon ring or an unsaturated aliphatic hydrocarbon ring. Furthermore, the aliphatic hydrocarbon ring may be a monocyclic aliphatic hydrocarbon ring having one ring or a polycyclic aliphatic hydrocarbon ring having multiple rings. The number of carbon atoms in the aliphatic hydrocarbon ring is preferably 4 or more, more preferably 5 or more, preferably 14 or less, more preferably 10 or less, and even more preferably 6 or less.

[0044] Ring B bAmong the aliphatic hydrocarbon rings mentioned above, monocyclic aliphatic hydrocarbon rings are preferred, and monocyclic saturated aliphatic hydrocarbon rings are more preferred. Examples of monocyclic saturated aliphatic hydrocarbon rings include monocycloalkane rings such as cyclobutane rings, cyclopentane rings, cyclohexane rings, cycloheptane rings, and cyclooctane rings, with cyclohexane rings being preferred.

[0045] Ring B b Examples of substituents that the aliphatic hydrocarbon ring may have include halogen atoms, alkyl groups, alkenyl groups, aryl groups, aralkyl groups, alkyl-oxy groups, alkenyl-oxy groups, aryl-oxy groups, and aralkyl-oxy groups. Among these, alkyl groups and alkenyl groups are preferred, and alkyl groups are even more preferred.

[0046] Examples of halogen atoms include fluorine, chlorine, bromine, and iodine.

[0047] Alkyl groups can be linear, branched, or cyclic monovalent aliphatic saturated hydrocarbon groups. The number of carbon atoms in an alkyl group is preferably 1 to 14, more preferably 1 to 6, and even more preferably 1 to 3. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, sec-pentyl, neopentyl, tert-pentyl, hexyl, isohexyl, heptyl, isoheptyl, octyl, isooctyl, tert-octyl, cyclopentyl, cyclohexylmethyl, and the like.

[0048] The alkenyl group can be a linear, branched, or cyclic monovalent aliphatic unsaturated hydrocarbon group having at least one carbon-carbon double bond. The number of carbon atoms in the alkenyl group is preferably 2 to 14, more preferably 2 to 6, and even more preferably 2 or 3. Examples of alkenyl groups include vinyl group, propenyl group (allyl group, 1-propenyl group, isopropenyl group), butenyl group (1-butenyl group, clotyl group, methallyl group, isoclotyl group, etc.), pentenyl group (1-pentenyl group, etc.), hexenyl group (1-hexenyl group, etc.), heptenyl group (1-heptenyl group, etc.), octenyl group (1-octenyl group, etc.), cyclopentenyl group (2-cyclopentenyl group, etc.), and cyclohexenyl group (3-cyclohexenyl group, etc.).

[0049] The aryl group can be a monovalent aromatic hydrocarbon group, which is formed by removing one hydrogen atom from an aromatic hydrocarbon. The number of carbon atoms in the aryl group is preferably 6 to 14, more preferably 6 to 10. Examples of aryl groups include the phenyl group, the 1-naphthyl group, and the 2-naphthyl group.

[0050] The aralkyl group may be an alkyl group substituted with one or more (preferably one) aryl groups. The number of carbon atoms in the aralkyl group is preferably 7 to 15, more preferably 7 to 11. Examples of aralkyl groups include benzyl group, phenethyl group, hydrocinnamyl group, α-methylbenzyl group, α-cumyl group, 1-naphthylmethyl group, and 2-naphthylmethyl group.

[0051] In equation (B1), i b and j b Each of these independently represents an integer of 0 or 1 or greater. Also, i b and j b The sum is usually 6 or more, preferably 8 or more, and more preferably 10 or more. b and j b i is preferably an integer between 0 and 20, more preferably an integer between 1 and 20, and even more preferably an integer between 5 and 10. b and j bThey may be the same or different. In particular, i b and j b It is particularly preferably 8.

[0052] An example of a maleimide resin containing the substructure represented by formula (B1) is the maleimide resin represented by the following formula (B2).

[0053] [ka]

[0054] (In equation (B2), R b10 Each of these independently represents a substituent; ring C b Each independently represents an aromatic ring which may have substituents; D b1 and D b2 These are, independently, single bonds, -C(R x ) indicates -2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, -NHCO-, -COO-, or -OCO-; R x Each independently represents either a hydrogen atom or an alkyl group; c b Each independently represents either 0 or 1; d b Each of these independently represents an integer of 0 or 1 or greater; e b Each independently represents 0, 1, or 2; n b represents an integer of 0 or greater than or equal to 1; other symbols are as described above. c b Unit, d b Units and n b The units may be the same or different for each unit.

[0055] In equation (B2), R b10 Each of these independently represents a substituent. b10 Examples of substituents include halogen atoms, alkyl groups, alkenyl groups, aryl groups, aralkyl groups, alkyl-oxy groups, alkenyl-oxy groups, aryl-oxy groups, and aralkyl-oxy groups.

[0056] In equation (B2), ring C b Each of these independently represents an aromatic ring which may have substituents. The aromatic ring is preferably an aromatic carbocyclic ring. The aromatic ring is preferably a 5-14 membered ring, more preferably a 6-14 membered ring, and even more preferably a 6-10 membered ring. Examples of aromatic rings include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, and the like, more preferably a benzene ring or a naphthalene ring, and even more preferably a benzene ring.

[0057] Ring C b Examples of substituents that the aromatic ring may have include halogen atoms, alkyl groups, alkenyl groups, aryl groups, aralkyl groups, alkyl-oxy groups, alkenyl-oxy groups, aryl-oxy groups, and aralkyl-oxy groups. Among these, alkyl groups are preferred.

[0058] In equation (B2), D b1 and D b2 These are, independently, single bonds, -C(R x )2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, -NHCO-, -COO-, or -OCO-, preferably a single bond, -C(R x )2-, or -O-, more preferably -O-. x Each of these independently represents a hydrogen atom or an alkyl group, preferably a hydrogen atom or a methyl group.

[0059] In equation (B2), c b Each of these independently represents either 0 or 1.

[0060] In equation (B2), d b Each of these independently represents an integer of 0 or 1 or more, preferably 0, 1, 2, or 3, more preferably 0, 1, or 2, and even more preferably 0 or 2.

[0061] In equation (B2), e b Each of these independently represents 0, 1, or 2, preferably 0.

[0062] In equation (B2), n b This represents an integer of 0 or greater than or equal to 1, preferably an integer between 0 and 10.

[0063] Examples of substructures included in equation (B2) and represented by equation (B3) below include the substructures represented by equations (b-1) to (b-3) described later.

[0064] [ka]

[0065] [ka]

[0066] (In the formula, * indicates a bonding site.)

[0067] Examples of commercially available maleimide resins containing the substructure represented by formula (B1) include "BMI-689," "BMI-1500," "BMI-1700," "BMI-3000," and "BMI-3000J" from Designer Molecules Inc., and "SLK-1500" and "SLK-6895" from Shin-Etsu Chemical Co., Ltd.

[0068] (B) Another preferred example of a maleimide resin is the maleimide resin represented by formula (B4). This maleimide resin is usually classified as (B-1) aromatic maleimide resin.

[0069] [ka]

[0070] (In equation (B4), ring E b , ring F b and ring G b Each independently represents an aromatic ring which may have substituents; Z b1 and Zb2 These are, independently, single bonds, -C(R z ) indicates -2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, or -NHCO-; R z Each of these independently represents either a hydrogen atom or an alkyl group; f b g represents an integer greater than or equal to 1; g b Each independently represents either 0 or 1; h b Each of these independently represents 0, 1, 2, or 3. b Unit: g b Units and h b The units may be the same or different for each unit.

[0071] In equation (B4), ring E b , ring F b and ring G b Each independently represents an aromatic ring which may have substituents. Ring E b , ring F b and ring G b Examples of substituents in this ring include halogen atoms, alkyl groups, alkenyl groups, aryl groups, aralkyl groups, alkyl-aryl-alkyl groups, alkyl-oxy groups, alkenyl-oxy groups, aryl-oxy groups, and aralkyl-oxy groups. b , ring F b and ring G b preferably a benzene ring which may have substituents, and more preferably a benzene ring which may be substituted with a group selected from alkyl groups, aryl groups and aralkyl groups. In one example, ring E b , ring F b and ring G b It is even more preferable that the ring E is an unsubstituted benzene ring. In another example, ring E b The ring F is preferably a benzene ring substituted with alkyl groups such as methyl and ethyl groups, and this benzene ring may also be substituted with alkyl-aryl-alkyl groups such as ethylphenylethyl groups; ring F b and ring G bIt is more preferable that it is a benzene ring which may be substituted with an alkyl group such as a methyl group and an ethyl group.

[0072] In formula (B4), Z b1 each independently represents a single bond, -C(R z )2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, or -NHCO-, preferably a single bond or -C(R z )2-, and more preferably a single bond. R z each independently represents a hydrogen atom or an alkyl group, preferably a hydrogen atom or a methyl group.

[0073] In formula (B4), Z b2 each independently represents a single bond, -C(R z )2-, -O-, -CO-, -S-, -SO-, -SO2-, -CONH-, or -NHCO-, preferably -C(R z )2- or -O-. R z as described above, each independently represents a hydrogen atom or an alkyl group. When Z b2 is -C(R z )2-, R z is preferably a hydrogen atom or a methyl group. In one example, when Z b2 is -C(R z )2-, by both of R z representing a hydrogen atom, the Z b2 may be -CH2-. In another example, when Z b2 is -C(R z )2-, by both of R z representing a methyl group, the Z b2 may be -C(CH3)2-. In yet another example, when Z b2 is -C(R z )2-, by one of R z representing a hydrogen atom and the other representing a methyl group, the Z b2 may be -CH(CH3)-.

[0074] In formula (B4), fb represents an integer greater than or equal to 1, preferably an integer between 1 and 100, and more preferably an integer between 1 and 10.

[0075] In formula (B4), g b Each of these independently represents either 0 or 1, preferably 1.

[0076] In equation (B4), h b Each of these independently represents 0, 1, 2, or 3, preferably 0, 1, or 2, more preferably 0 or 1, and even more preferably 1.

[0077] Examples of commercially available maleimide resins represented by formula (B4) include "MIR-3000-70MT," "MIR-5000," and "MIR-5000-60T" from Nippon Kayaku Co., Ltd., and "BMI-70" and "BMI-80" from K.I. Kasei Co., Ltd.

[0078] (B) Another preferred example of a maleimide resin is the maleimide resin represented by formula (B5). This maleimide resin is usually classified as (B-1) aromatic maleimide resin.

[0079] [ka]

[0080] (In formula (B5), R b30 Each independently represents an alkyl group; ring H b and Ring I b Each independently represents an aromatic ring which may have substituents; m b m represents an integer greater than or equal to 1. b The units may be the same or different for each unit.

[0081] In equation (B5), R b30 Each of these independently represents an alkyl group, preferably a methyl group.

[0082] In equation (B5), ring H b Each independently represents an aromatic ring which may have substituents. Ring H b Examples of substituents in this ring include halogen atoms, alkyl groups, alkenyl groups, aryl groups, aralkyl groups, alkyl-oxy groups, alkenyl-oxy groups, aryl-oxy groups, and aralkyl-oxy groups. b This is preferably a benzene ring which may have substituents, more preferably a benzene ring which may be substituted with an alkyl group, and even more preferably a benzene ring which is substituted with an alkyl group.

[0083] In equation (B5), ring I b Each of these independently represents an aromatic ring which may have substituents. Ring I b Examples of substituents in this ring include halogen atoms, alkyl groups, alkenyl groups, aryl groups, aralkyl groups, alkyl-oxy groups, alkenyl-oxy groups, aryl-oxy groups, and aralkyl-oxy groups. Ring I b This is preferably a benzene ring which may have substituents, more preferably a benzene ring which may be substituted with an alkyl group, and even more preferably an unsubstituted benzene ring.

[0084] In equation (B5), m b This represents an integer greater than or equal to 1, preferably an integer between 1 and 20.

[0085] The maleimide resin represented by formula (B5) can be manufactured, for example, by the method described in the Japan Institute of Invention and Innovation Publication No. 2020-500211 or a similar method.

[0086] (B) Another preferred example of a maleimide resin is a maleimide resin having a substructure represented by formula (B6), a substructure represented by formula (B7) chemically bonded to the substructure represented by formula (B6), and a substructure represented by formula (B8) chemically bonded to the substructure represented by formula (B6). This maleimide resin is usually classified as (B-1) an aromatic maleimide resin.

[0087] [ka]

[0088] (In formula (B6), R b40 Each of these independently represents an alkyl group having 1 to 18 carbon atoms, and u b represents an integer between 0 and 4, and v b represents the average number of repeating units, and the two *s each represent a bond, with one of the bond being L in equation (B7). b41 or L b42 A chemical bond is formed at this position, and the other bond is L in formula (B8) b43 or L b44 This indicates that a chemical bond is formed at this position.

[0089] [ka]

[0090] (In formula (B7) or (B8), R b41 and R b43 Each of these independently represents a hydrocarbon group with 1 to 18 carbon atoms. R b42 and R b44 Each of these independently represents a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms. L b41 ~L b44 Each of these independently represents a bonding bond or a hydrogen atom, except L b41 or L b42 At this position, it is chemically bonded to the substructure represented by formula (B6), and L b43 or L b44 At this position, L is chemically bonded to the substructure represented by formula (B6), and L is not chemically bonded to the substructure represented by formula (B6). b43 ~L b42 (This is a hydrogen atom.)

[0091] In equation (B6), the two * symbols each represent a bond. Of the two bonds, one of them is L in equation (B7) above. b41 or L b42 A chemical bond is formed at the position. The other bond is L in formula (B8) above. b43 or L b44 The chemical bond is formed at the position. Therefore, the benzene rings in formulas (B7) and (B8) are chemically bonded to the substructure represented by formula (B6) at the para position or one ortho position relative to the maleimide group.

[0092] In equation (B6), R b40 Each of these independently represents a hydrocarbon group having 1 to 18 carbon atoms. The number of carbon atoms in the hydrocarbon group is preferably 1 to 12, and more preferably 1 to 6. b40 R in formula (B) is preferably an alkyl group, more preferably a linear alkyl group, and particularly preferably a methyl group. b40 The benzene ring to which it is bonded may also be a benzene ring contained within the benzyl ether skeleton.

[0093] In equation (B6), u b R represents an integer between 0 and 4, preferably an integer less than or equal to 2, and particularly preferably 2. b40 In a benzene ring to which R is bonded, if the 1st and 3rd positions are bonded by a methylene group, then the 4th and 6th positions are R b40 It is preferable that they are bonded together.

[0094] In equation (B6), v b represents the average number of repeating units, preferably 0 to 50, preferably 0 to 30, and preferably 0 to 15. b can be a number greater than 0, or greater than or equal to 1.

[0095] In equation (B7), L b41 or L b42 Each of these independently represents a bond or a hydrogen atom. However, L b41 or L b42At least one of the positions, the substructure represented by formula (B6) and the substructure represented by formula (B7) are chemically bonded. In addition, L does not chemically bond with the substructure represented by formula (B6). b41 or L b42 L is a hydrogen atom. b41 and L b42 A substructure represented by formula (B6) may be chemically bonded to each of these two locations.

[0096] In equation (B7), R b41 Each of these independently represents a hydrocarbon group having 1 to 18 carbon atoms. The number of carbon atoms in the hydrocarbon group is preferably 1 to 12, and more preferably 1 to 6. b41 A linear alkyl group is preferred, and an ethyl group is particularly preferred.

[0097] In equation (B7), R b42 Each of these independently represents a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms. The number of carbon atoms in the hydrocarbon group is preferably 1 to 12, and more preferably 1 to 6. b42 The hydrogen atom or alkyl group is preferred, and the hydrogen atom or linear alkyl group is more preferred.

[0098] In equation (B8), L b43 or L b44 Each of these independently represents a bond or a hydrogen atom. However, L b43 or L b44 At least one of the positions, the substructure represented by formula (B6) and the substructure represented by formula (B8) are chemically bonded. In addition, L does not chemically bond with the substructure represented by formula (B6). b43 or L b44 L is a hydrogen atom. b43 and L b44 A substructure represented by formula (B6) may be chemically bonded to each of the two locations.

[0099] In equation (B8), R b43Each of these independently represents a hydrocarbon group having 1 to 18 carbon atoms. The number of carbon atoms in the hydrocarbon group is preferably 1 to 12, and more preferably 1 to 6. b43 A linear alkyl group is preferred, and an ethyl group is particularly preferred.

[0100] In equation (B8), R b44 Each of these independently represents a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms. The number of carbon atoms in the hydrocarbon group is preferably 1 to 12, and more preferably 1 to 6. b44 The hydrogen atom or alkyl group is preferred, and the hydrogen atom or linear alkyl group is more preferred.

[0101] The maleimide resin containing the substructure represented by formula (B6), the substructure represented by formula (B7), and the substructure represented by formula (B8) can be manufactured, for example, by the method described in Japanese Patent Application Publication No. 2024-4392 or a similar method.

[0102] (B) The maleimide group equivalent of the maleimide resin is preferably 30 g / eq. or more, more preferably 75 g / eq. or more, even more preferably 150 g / eq. or more, even more preferably 200 g / eq. or more, even more preferably 250 g / eq. or more, even more preferably 300 g / eq. or more, preferably 2,500 g / eq. or less, more preferably 2,000 g / eq. or less, even more preferably 1,500 g / eq. or less, even more preferably 1,000 g / eq. or less, and even more preferably 500 g / eq. or less. The maleimide group equivalent represents the mass of the resin per equivalent of one maleimide group.

[0103] (B) The weight-average molecular weight of the maleimide resin is preferably 100 or more, more preferably 150 or more, even more preferably 200 or more, even more preferably 400 or more, even more preferably 500 or more, even more preferably 600 or more, preferably 10,000 or less, more preferably 7,000 or less, even more preferably 5,000 or less, and even more preferably 3,000 or less.

[0104] (B-1) The amount of aromatic maleimide resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 3.5% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition. (B-1) When the amount of aromatic maleimide resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and the glass transition temperature, surface roughness and adhesion of the cured product can usually be made particularly good.

[0105] (B-1) The amount of aromatic maleimide resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and particularly preferably 11% by mass or less, based on 100% by mass of the resin components of the resin composition. (B-1) When the amount of aromatic maleimide resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and furthermore, the glass transition temperature, surface roughness and adhesion of the cured product can usually be made particularly good.

[0106] (B-2) The amount of aliphatic maleimide resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 3.5% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition. (B-2) When the amount of aliphatic maleimide resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and furthermore, the glass transition temperature, surface roughness and adhesion of the cured product can usually be made particularly good.

[0107] (B-2) The amount of aliphatic maleimide resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and particularly preferably 11% by mass or less, based on 100% by mass of the resin components of the resin composition. (B-2) When the amount of aliphatic maleimide resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and furthermore, the glass transition temperature, surface roughness and adhesion of the cured product can usually be made particularly good.

[0108] The ratio of the mass of the aliphatic maleimide resin (B-2) to the mass of the aromatic maleimide resin (B-1) ((B-2) / (B-1)) may be 0.0 or greater than 0.0. This mass ratio ((B-2) / (B-1)) is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.5 or more, preferably 1000 or less, more preferably 100 or less, and even more preferably 10 or less.

[0109] (B) The amount of maleimide resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 6% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition. (B) When the amount of maleimide resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of the cured product can be particularly effectively improved, and the glass transition temperature, surface roughness and adhesion of the cured product can also be particularly good.

[0110] (B) The amount of maleimide resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, particularly preferably 8% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on 100% by mass of the resin components of the resin composition. When the amount of maleimide resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and furthermore, the glass transition temperature, surface roughness and adhesion of the cured product can usually be made particularly good.

[0111] The ratio of (B) maleimide resin to (A) epoxy resin ((B) maleimide resin / (A) epoxy resin) is preferably 0.01 or more, more preferably 0.10 or more, even more preferably 0.20 or more, particularly preferably 0.23 or more, preferably 2.0 or less, more preferably 1.0 or less, even more preferably less than 0.6, and even more preferably 0.5 or less. When the ratio ((B) maleimide resin / (A) epoxy resin) is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and the glass transition temperature, surface roughness, and adhesion of the cured product can usually be particularly good.

[0112] <(C) Inorganic filler> The resin composition according to this embodiment includes (C) an inorganic filler as component (C). The inorganic filler (C) is a particle of an inorganic material. Therefore, the inorganic filler (C) is included in the resin composition in granular form and is usually included in the cured product while maintaining that granular state.

[0113] (C) Inorganic materials are typically inorganic compounds used to form the inorganic filler. (C) Examples of materials for the inorganic filler include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica and alumina are preferred, and silica is particularly preferred. Therefore, (C) the inorganic filler preferably contains silica, and may contain only silica. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Furthermore, spherical silica is preferred as the silica. (C) The inorganic filler may be used alone or in combination of two or more types.

[0114] (C) Inorganic fillers can be classified into hollow inorganic fillers having voids inside and solid inorganic fillers not having voids inside. (C) Inorganic fillers may consist only of hollow inorganic fillers, or only of solid inorganic fillers, or a combination of hollow inorganic fillers and solid inorganic fillers.

[0115] Hollow inorganic fillers having internal voids typically have a porosity greater than 0 volume% because they contain voids. (C) When the inorganic filler includes hollow inorganic fillers, the dielectric constant of the cured product can be lowered. The porosity range of the hollow inorganic filler is preferably 5 volume% or more, more preferably 10 volume% or more, even more preferably 20 volume% or more, preferably 95 volume% or less, more preferably 90 volume% or less, and even more preferably 85 volume% or less. The porosity P (volume%) of a particle is defined as the volume-based ratio of the total volume of voids (total volume of voids / volume of particle) to the total volume of the particle based on the outer surface of the particle. This porosity P is measured D of the actual density (apparent density) of the particle. M (g / cm 3 ), and the theoretical value (true density) of the material density of the particle-forming material D T (g / cm 3 Using ), it can be calculated by the following formula (M1).

[0116]

number

[0117] The amount of hollow inorganic filler may be 0% by mass or more than 0% by mass, preferably 1% or more by mass, more preferably 2% or more by mass, even more preferably 3% or more by mass, preferably 80% or less by mass, more preferably 60% or less by mass, and even more preferably 40% or less by mass.

[0118] (C) Examples of commercially available inorganic fillers include "SP60-05" and "SP507-05" from Nippon Steel Chemical & Material Co., Ltd.; "YC100C", "YA050C", "YA050C-MJE", "YA010C", "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" from Admatex Co., Ltd.; "UFP-30", "DAW-03", and "FB-105FD" from Denka Co., Ltd.; "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" from Tokuyama Corporation; "Cellspheres" and "MGH-005" from Taiheiyo Cement Corporation; and "LHP-208" from Ube Eximo Co., Ltd.

[0119] (C) The average particle size of the inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less, and even more preferably 2 μm or less.

[0120] (C) The average particle size of inorganic fillers can be measured by the laser diffraction-scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be created on a volume basis using a laser diffraction-scattering particle size distribution analyzer, and the median diameter can be used as the average particle size. A sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing them with ultrasound for 10 minutes. The sample can be measured using a laser diffraction-type particle size distribution analyzer with blue and red light source wavelengths, using a flow cell method to measure the volume-based particle size distribution of the inorganic filler, and the average particle size can be calculated as the median diameter from the obtained particle size distribution. An example of a laser diffraction-type particle size distribution analyzer is the "LA-960" manufactured by Horiba, Ltd.

[0121] (C) The specific surface area of ​​the inorganic filler is preferably 0.1 m². 2 / g or more, more preferably 0.5m 2 / g or more, more preferably 1m 2 / g or more, particularly preferably 3m 2It is 100m or more / g, preferably 100m 2 / g or less, more preferably 70m 2 / g or less, more preferably 50m 2 / g or less, particularly preferably 40m 2 It is less than / g. (C) The specific surface area of ​​the inorganic filler can be measured by adsorbing nitrogen gas onto the sample surface using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountec Co., Ltd.) according to the BET method, and calculating the specific surface area using the BET multipoint method.

[0122] (C) The inorganic filler is preferably treated with a surface treatment agent from the viewpoint of improving moisture resistance and dispersibility. Examples of surface treatment agents include fluorine-containing silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, titanate coupling agents, etc. The surface treatment agent may be used alone or in any combination of two or more types.

[0123] Examples of commercially available surface treatment agents include "KBM403" (3-glycidoxypropyltrimethoxysilane), "KBM803" (3-mercaptopropyltrimethoxysilane), "KBE903" (3-aminopropyltriethoxysilane), "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), "SZ-31" (hexamethyldisilazane), "KBM103" (phenyltrimethoxysilane), "KBM-4803" (long-chain epoxy-type silane coupling agent), and "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane), all manufactured by Shin-Etsu Chemical Co., Ltd.

[0124] From the viewpoint of improving the dispersibility of the inorganic filler, the degree of surface treatment by the surface treatment agent is preferably within a specific range. Specifically, 100% by mass of the inorganic filler is preferably surface-treated with 0.2% to 5% by mass of the surface treatment agent, more preferably with 0.2% to 3% by mass of the surface treatment agent, and even more preferably with 0.3% to 2% by mass of the surface treatment agent.

[0125] The degree of surface treatment by a surface treatment agent can be evaluated by the amount of carbon per unit surface area of ​​the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of ​​the inorganic filler should be 0.02 mg / m². 2 The above is preferred, and 0.1 mg / m² 2 The above is more preferable, 0.2 mg / m² 2 The above is even more preferable. On the other hand, from the viewpoint of preventing an increase in the melt viscosity of the resin composition layer, 1.0 mg / m 2 The following is preferred: 0.8 mg / m² 2 The following is more preferable: 0.5 mg / m² 2 The following are even more preferable.

[0126] (C) The amount of carbon per unit surface area of ​​an inorganic filler can be measured after cleaning the inorganic filler with a solvent (e.g., methyl ethyl ketone (MEK)) following surface treatment. Specifically, a sufficient amount of MEK is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solids, the amount of carbon per unit surface area of ​​the inorganic filler can be measured using a carbon analyzer. A carbon analyzer such as the "EMIA-320V" manufactured by Horiba, Ltd. can be used.

[0127] (C) The amount of inorganic filler is typically 60% by mass or more, preferably 63% by mass or more, more preferably 65% ​​by mass or more, preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition. (C) When the amount of inorganic filler is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and the glass transition temperature, surface roughness and adhesion of the cured product can also be particularly good.

[0128] <(D) Cyclic phosphazene compounds> The resin composition according to this embodiment contains a cyclic phosphazene compound as component (D). The cyclic phosphazene compound (D) is represented by formula (1). The cyclic phosphazene compound (D) can usually enhance the flame retardancy of the cured product of the resin composition.

[0129] [ka]

[0130] In equation (1), R 1 and R 2 Each of these independently represents a nitro group, one of the following (R-1) and (R-2); or one of the following (R-3).

[0131] (R-1): An alkyl or alkoxy group having 1 to 8 carbon atoms, which may be substituted with at least one group selected from the group consisting of alkyl groups and aryl groups having 1 to 6 carbon atoms.

[0132] R 1 and R 2Examples of alkyl groups that fall under this category include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, 2-ethylhexyl group, benzyl group, and 2-phenylethyl group. 1 and R 2 Examples of alkoxy groups that fall under this category include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, n-pentoxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, n-nonyloxy group, 2-ethylhexyloxy group, benzyloxy group, and 2-phenylethyloxy group. Among these, R is classified as (R-1). 1 and R 2 The preferred groups are methyl, ethyl, n-propyl, benzyl, and methoxy, with methyl and ethyl groups being more preferred.

[0133] (R-2): An aryl group or aryloxy group having 6 to 20 carbon atoms, which may be substituted with at least one group selected from the group consisting of alkyl groups and aryl groups having 1 to 6 carbon atoms.

[0134] R 1 and R 2 Examples of aryl groups that fall under this category include phenyl group, methylphenyl group, dimethylphenyl group, ethylphenyl group, ethylmethylphenyl group, diethylphenyl group, n-propylphenyl group, isopropylphenyl group, isopropylmethylphenyl group, isopropylethylphenyl group, diisopropylphenyl group, n-butylphenyl group, sec-butylphenyl group, tert-butylphenyl group, n-pentylphenyl group, n-hexylphenyl group, phenylphenyl group, naphthyl group, anthryl group, and phenanthryl group. 1 and R 2Examples of aryloxy groups that fall under this category include phenyloxy group, methylphenyloxy group, dimethylphenyloxy group, ethylphenyloxy group, ethylmethylphenyloxy group, diethylphenyloxy group, n-propylphenyloxy group, isopropylphenyloxy group, isopropylmethylphenyloxy group, isopropylethylphenyloxy group, diisopropylphenyloxy group, n-butylphenyloxy group, sec-butylphenyloxy group, tert-butylphenyloxy group, n-pentylphenyloxy group, n-hexylphenyloxy group, phenylphenyloxy group, naphthyloxy group, anthryloxy group, and phenanthryloxy group. Among these, R is classified as (R-2). 1 and R 2 The preferred groups are phenyl, methylphenyl, dimethylphenyl, diethylphenyl, phenylphenyl, naphthyl, and phenyloxy groups, with phenyl and methylphenyl groups being more preferred.

[0135] (R-3): R 1 and R 2 A saturated or unsaturated cyclic structure is formed between the two, and this cyclic structure may be substituted with an alkyl group or carbonyl group having 1 to 6 carbon atoms.

[0136] Examples of phosphazene units having a saturated cyclic structure include the repeating unit represented by equation (2-1) and the repeating unit represented by equation (2-2).

[0137] [ka]

[0138] (In equations (2-1) and (2-2), the symbols L and m have the same meaning as in equation (1).)

[0139] Therefore, for example, when m is 0, examples of phosphazene units having a saturated cyclic structure include the repeating unit represented by equation (2-1-1) and the repeating unit represented by equation (2-2-1).

[0140] [ka]

[0141] Furthermore, an example of a phosphazene unit having the relevant unsaturated cyclic structure is the repeating unit represented by the following equation (2-3).

[0142] [ka]

[0143] (In equation (2-3), the symbols L and m are equivalent to those in equation (1).)

[0144] Therefore, for example, when m is 0, an example of a phosphazene unit having an unsaturated cyclic structure is the repeating unit represented by equation (2-3-1).

[0145] [ka]

[0146] In equation (1), R 1 and R 2 These can be the same or different. Also, multiple Rs 1 These may be the same or different from one another. Furthermore, multiple Rs 2 They may be the same as, or they may be different from, each other.

[0147] In equation (1), L represents a divalent heteroatom. An example of L is the oxygen atom.

[0148] In equation (1), a and b each independently represent integers from 0 to 4. In detail, a is substituent R 1 This represents the number of substituents R, which is usually 0 or greater, usually 4 or less, and preferably 2 or less. Also, b is substituent R 2 It represents the number, which is usually 0 or greater, usually 4 or less, and preferably 2 or less.

[0149] In equation (1), each m independently represents either 0 or 1. Of these, 0 is preferred for m.

[0150] Symbols a, b, R 1 , R 2 Examples of combinations of L and m are shown in Table 1 below. Among these, combinations 1, 2, and 3 are preferred, and combinations 1 and 2 are more preferred.

[0151] [Table 1]

[0152] In formula (1), n ​​represents an integer from 3 to 8. More specifically, n is usually 3 or greater, usually 8 or less, preferably 4 or less. In formula (1), n ​​represents the number of phosphazene units represented by formula (2). Therefore, the (D) cyclic phosphazene compound represented by formula (1) may be a cyclic phosphazene compound with n=3 (trimer), a cyclic phosphazene compound with n=4 (tetramer), a cyclic phosphazene compound with n=5 (pentamer), a cyclic phosphazene compound with n=6 (hexamer), a cyclic phosphazene compound with n=7 (heptamer), or a cyclic phosphazene compound with n=8 (octamer).

[0153] In formula (1), n ​​is preferably small. Therefore, when using two or more (D) cyclic phosphazene compounds with different n values, it is preferable to use more of the ones with small n values. In one preferred example, the amount of compounds with n 3 or 4 (i.e., trimers and tetramers) is 95% by mass or more of the total amount of (D) cyclic phosphazene compounds (100% by mass). In another preferred example, the amount of compounds with n 3 (i.e., trimers) is 95% by mass or more of the total amount of (D) cyclic phosphazene compounds (100% by mass).

[0154] In formula (1), the structures of the phosphazene units represented by formula (2) are independent of each other. Therefore, the structures of the n phosphazene units contained in one molecule of the (D) cyclic phosphazene compound may be the same or different. Consequently, the (D) cyclic phosphazene compound may consist entirely of identical phosphazene units, or it may contain two or more types of phosphazene units with different structures.

[0155] (D)Specific examples of cyclic phosphazene compounds include any of the following: a cyclotriphosphazene compound where n in formula (1) is 3, a cyclotetraphosphazene compound where n in formula (1) is 4, a cyclopentaphosphazene compound where n in formula (1) is 5, a cyclohexaphosphazene compound where n in formula (1) is 6, a cycloheptaphosphazene compound where n in formula (1) is 7, or a cyclooctaphosphazene compound where n in formula (1) is 8, and a, b, R 1 , R 2 Examples include combinations of L and m as shown in Table 1.

[0156] In these specific examples, the phosphazene units contained in one molecule may be different, but it is preferable that they be the same. In such preferred specific examples, a, b, and R in formula (2) representing the phosphazene units are 1 , R 2The combinations of L and m are the same for any phosphazene unit contained in one molecule. Therefore, specific examples of preferred (D) cyclic phosphazene compounds include those represented by the following formulas (1-1) to (1-19). In formulas (1-1) to (1-19), n has the same meaning as in formula (1).

[0157]

Chemical formula

[0158]

Chemical formula

[0159] Among the above-mentioned specific examples, a cyclotriphosphazene compound in which n in formula (1) is 3 or a cyclotetraphosphazene compound in which n in formula (1) is 4 and which is of combination example 1, 2 or 3 is preferred; a cyclotriphosphazene compound in which n in formula (1) is 3 and which is of combination example 1 or example 2 is more preferred. Therefore, compounds represented by formulas (1-1) to (1-3) and in which n is 3 or 4 are preferred; compounds represented by formulas (1-1) to (1-2) and in which n is 3 are more preferred.

[0160] <N (D) cyclic phosphazene compounds may be used alone or in combination of two or more.

[0161] (D) cyclic phosphazene compounds may have stereoisomers. For example, a cyclotriphosphazene compound in which n in formula (1) is 3 and which is of combination example 1 (that is, the compound represented by formula (1-1)), when represented by showing three phosphazene units, is represented by the following formula (1-1-1).

[0162]

Chemical formula

[0163] The compound represented by formula (1-1-1) may have diastereomers. Therefore, when the compound is produced, the compound represented by formula (1-1-1) may be obtained as a mixture of those diastereomers. Specifically, the compound represented by formula (1-1-1) may be obtained as a mixture of a cis-cis-cis type represented by the following formula (1-1-2) (hereinafter sometimes referred to as "cis type") and a trans-cis-trans type represented by the following formula ( (1-1-3) (hereinafter referred to as "trans type") in the configuration of adjacent phosphazene units.

[0164] [Chemical formula]

[0165] Such a mixture of diastereomers may be used as a mixture as it is, or the cis type and the trans type may be isolated and used as a single substance of each type. Examples of the isolation method include, for example, a method by a combination of separation using solubility in a solvent such as toluene and filtration, a solvent extraction method, a recrystallization method, a separation method by column chromatography, and the like.

[0166] In addition, the (D) cyclic phosphazene compound in which n is 4 or more in formula (1) may have stereoisomers having many diastereomers and enantiomers. These stereoisomers may be used as a mixture containing a plurality of stereoisomers, or the stereoisomers may be separated and used as a single substance.

[0167] (D) cyclic phosphazene compounds can be produced, for example, by the method described in JP-A-2022-21767. Also, a commercially available product of (D) cyclic phosphazene compound may be purchased. Examples of commercially available (D) cyclic phosphazene compounds include "FP-72TP" (formula (1-1)) and "B" (formula (1-19)) manufactured by Fushimi Seisakusho Co., Ltd., and the like.

[0168] (D) The cyclic phosphazene compound preferably has a melting point of 260°C or higher, more preferably 270°C or higher, and even more preferably 280°C or higher. (D) There is no particular upper limit to the melting point of the cyclic phosphazene compound, and it may be, for example, 500°C or lower, 400°C or lower, 350°C or lower, etc. (D) The melting point of the cyclic phosphazene compound can be measured using a differential scanning calorimeter by raising the temperature from 25°C to 500°C at a heating rate of 20°C / min.

[0169] (D) The cyclic phosphazene compound preferably has a specific solubility in cyclohexanone. The solubility of (D) the cyclic phosphazene compound in cyclohexanone can be measured, for example, by performing a first dissolution test in which the (D) cyclic phosphazene compound is dissolved in 10 g of cyclohexanone by sonication at 25°C for 10 minutes. Specifically, the range of the amount of (D) cyclic phosphazene compound dissolved in cyclohexanone in the first dissolution test is preferably 0.04 g or less, more preferably 0.03 g or less, and even more preferably 0.02 g or less. The lower limit may be 0.00 g or more than 0.00 g.

[0170] The first dissolution test of the (D) cyclic phosphazene compound can be performed by the following method. Add 0.5 g of the (D) cyclic phosphazene compound to 10 g of cyclohexanone and sonicate for 10 minutes while heating at 25°C, the test temperature for the first dissolution test, to dissolve the (D) cyclic phosphazene compound. If the added (D) cyclic phosphazene compound is completely dissolved in cyclohexanone, add another 0.5 g of the (D) cyclic phosphazene compound and repeat the sonication for 10 minutes. The cumulative amount added until a precipitate is observed just before the (D) cyclic phosphazene compound does not dissolve in cyclohexanone is obtained as the amount of (D) cyclic phosphazene compound dissolved in cyclohexanone. Specifically, the first dissolution test may be performed by the method described in the examples below.

[0171] The solubility of the (D) cyclic phosphazene compound in cyclohexanone may be measured by a second dissolution test, for example, in which the (D) cyclic phosphazene compound is dissolved in 10 g of cyclohexanone by sonication at 70°C for 10 minutes. Specifically, the range of the amount of (D) cyclic phosphazene compound that dissolves in cyclohexanone in the second dissolution test is preferably 0.3 g or less, more preferably 0.2 g or less, and even more preferably 0.1 g or less. The lower limit may be 0 g or more than 0 g.

[0172] (D) The second dissolution test of the cyclic phosphazene compound can be carried out in the same manner as the first dissolution test, except that the heating temperature during sonication is changed from 25°C to 70°C. Specifically, the second dissolution test may be carried out by the method described in the examples below.

[0173] When using a cyclic phosphazene compound (D) in which the difference in the amount of solubility measured in the first and second dissolution tests is small, the varnish stability can be improved particularly effectively. Specifically, the following applies: Certain solvents, such as cyclohexanone, have high boiling points and can dissolve (A) epoxy resin and (B) maleimide well. When there is little difference in the solubility of (D) cyclic phosphazene compounds in such solvents depending on the dissolution temperature, the precipitation of (D) cyclic phosphazene compounds is suppressed after storage of resin varnish containing the solvent, and the varnish stability can be improved particularly effectively.

[0174] The difference between the amount dissolved in the first dissolution test and the amount dissolved in the second dissolution test is preferably small. Specifically, the range of the difference in the amount dissolved is preferably 0.30 g or less, more preferably 0.20 g or less, and even more preferably 0.10 g or less. The lower limit may be 0.00 g or greater than 0.00 g. When the difference in the amount dissolved is within the above range, the varnish stability of the resin composition can be improved particularly effectively.

[0175] (D) The cyclic phosphazene compound is usually miscible with resin components other than the cyclic phosphazene compound and is included in the resin composition in granular form, and is included in the cured product while maintaining that granular state.

[0176] The average particle size range of the particles of the (D) cyclic phosphazene compound is preferably 1.5 μm or less, more preferably 1.2 μm or less, and even more preferably 1.0 μm or less. There is no particular lower limit, and it may be, for example, 0.05 μm or more, 0.1 μm or more, 0.2 μm or more, etc. When the average particle size of the particles of the (D) cyclic phosphazene compound is within the above range, the resin composition according to this embodiment can be applied to circuit boards having circuit wiring with a small pitch. The resin composition according to this embodiment has further improved varnish stability, so that the increase in particle size of the (D) cyclic phosphazene compound can be suppressed even with long-term storage. Therefore, the resin composition according to this embodiment can be applied to circuit boards having circuit wiring with a small pitch not only before storage but also after storage.

[0177] Generally, when the average particle size of the components in a resin varnish decreases, the particles tend to aggregate and precipitate more easily, leading to a decrease in varnish stability. However, the inventors unexpectedly discovered that when the average particle size of the particles of the (D) cyclic phosphazene compound is reduced, the varnish stability of the resin composition according to this embodiment is particularly improved. Specifically, the average particle size of the particles of the (D) cyclic phosphazene compound is more preferably 0.8 μm or less, 0.6 μm or less, or 0.5 μm or less. By reducing the average particle size of the particles of the (D) cyclic phosphazene compound in this way, the resin composition according to this embodiment can be used particularly suitably on circuit boards having small-pitch circuit wiring, not only before storage but also after storage.

[0178] (D) The maximum particle diameter range of the particles of the cyclic phosphazene compound is preferably 20 μm or less, more preferably 15 μm or less, even more preferably 12 μm or less, even more preferably 9 μm or less, even more preferably 8 μm or less, even more preferably 7 μm or less, and even more preferably 6 μm or less. There is no particular lower limit, and it may be, for example, 0.1 μm or more, 0.5 μm or more, 1 μm or more, etc. (D) When the maximum particle diameter of the particles of the cyclic phosphazene compound is within the above range, the resin composition according to this embodiment can be applied to circuit boards having circuit wiring with a small pitch. Furthermore, the resin composition according to this embodiment can be applied to circuit boards having circuit wiring with a small pitch not only before storage but also after storage.

[0179] (D) The average and maximum particle sizes of cyclic phosphazene compounds can be measured by laser diffraction and scattering based on Mie scattering theory. Specifically, a volume-based particle size distribution of (D) cyclic phosphazene compounds is created using a laser diffraction and scattering particle size distribution analyzer. The median diameter D50 of this particle size distribution is then used as the average particle size, and the maximum particle size D100 of this distribution is used as the maximum particle size. The particle size distribution of (D) cyclic phosphazene compounds can be measured in the same way as the particle size distribution of (C) inorganic fillers.

[0180] (D) The ratio of the average particle diameter of the cyclic phosphazene compound particles to (C) the average particle diameter of the inorganic filler is preferably within a specific range. Specifically, the ratio of the average particle diameter of the cyclic phosphazene compound particles to D a (Unit: μm) and (C) the average particle size of the inorganic filler is D b (Unit: μm) a and D b D a / D b The range is preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, even more preferably 2 or less, even more preferably 1.5 or less, even more preferably 1.2 or less, and also preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more. The ratio D of the average particle diameter a / Db When the ratio D of the average particle diameter is within the range described above, the resin composition according to this embodiment can be preferably applied to a circuit board having circuit wiring with a small pitch. a / D b When the range is as described above, the resin composition according to this embodiment exhibits further improved varnish stability, thereby suppressing the precipitation of components of the resin composition (resin varnish) even during long-term storage. Therefore, the resin composition according to this embodiment can be applied to circuit boards having small-pitch circuit wiring not only before storage but also after storage.

[0181] (D) The amount of the cyclic phosphazene compound is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, particularly preferably 0.8% by mass or more, preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition. When the amount of the cyclic phosphazene compound (D) is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and the glass transition temperature, surface roughness and adhesion of the cured product can usually be particularly good.

[0182] (D) The amount of the cyclic phosphazene compound is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, particularly preferably 2.5% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of the resin component of the resin composition. (D) When the amount of the cyclic phosphazene compound is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and the glass transition temperature, surface roughness and adhesion of the cured product can usually be particularly good.

[0183] As described above, since the (D) cyclic phosphazene compound can be contained in the resin composition in a particulate state, it is preferably used in a specific quantitative ratio with respect to the (C) inorganic filler also contained in the resin composition in a particulate state. Specifically, the range of the amount of the (D) cyclic phosphazene compound is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.5% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less, still more preferably 1% by mass or less, based on 100% by mass of the (C) inorganic filler.

[0184] (A) epoxy resin, (B) maleimide resin, (C) inorganic filler, and (D) cyclic phosphazene compound, the total amount of which is preferably 65% by mass or more, more preferably 70% by mass or more, still more preferably 75% by mass or more, particularly preferably 80% by mass or more, and usually 100% by mass or less, based on 100% by mass of the non-volatile component of the resin composition.

[0185] <! <(E) optional curable resin> The resin composition according to the present embodiment may contain, as an optional component, (E) an optional curable resin. The (E) optional curable resin as the component (E) does not include those corresponding to the above-described components (A) to (D). The (E) optional curable resin represents a curable resin other than the (A) epoxy resin and the (B) maleimide resin. The (E) optional curable resin may be used alone or in combination of two or more.

[0186] Examples of the (E) optional curable resin include curing agents. The curing agent represents a curable resin that can react with the (A) epoxy resin to cure the resin composition. The curing agent may be used alone or in combination of two or more.

[0187] Examples of curing agents include activated ester resins, phenolic resins, carbodiimide resins, cyanate resins, benzoxazine resins, acid anhydride resins, amine resins, and thiol resins. Among these, activated ester resins, phenolic resins, and carbodiimide resins are preferred; activated ester resins are even more preferred. Therefore, the curing agent preferably contains one or more selected from the group consisting of activated ester resins, phenolic resins, and carbodiimide resins; and it is even more preferable to contain an activated ester resin.

[0188] As the active ester resin, a resin having one or more, preferably two or more, active ester groups per molecule can be used. Among these, as the active ester resin, resins having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are preferred.

[0189] The activated ester resin is preferably obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. Particularly from the viewpoint of improving heat resistance, activated ester resins obtained from a carboxylic acid compound and a hydroxy compound are preferred, and activated ester resins obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound are more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolac. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by the condensation of two phenol molecules with one dicyclopentadiene molecule.

[0190] Specifically, preferred active ester resins include dicyclopentadiene-type active ester resins, naphthalene-type active ester resins containing a naphthalene structure, active ester resins containing an acetylated phenol novolac, and active ester resins containing a benzoylated phenol novolac; dicyclopentadiene-type active ester resins and naphthalene-type active ester resins are more preferred; and dicyclopentadiene-type active ester resins are even more preferred. As for dicyclopentadiene-type active ester resins, active ester resins containing a dicyclopentadiene-type diphenol structure are preferred.

[0191] Commercially available active ester resins include, for example, active ester resins containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", "EXB-8000L-65M", "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000L-65MT", "HPC-8000", "HPC-8000-65T", "EXB-8000H", and "NE-V-1100-70T" (manufactured by DIC Corporation); and active ester resins containing a naphthalene structure such as "EXB-8100L-65T", "EXB-8150-60T", and "EXB Examples include "-8150-62T", "EXB-9416-70BK", "HPC-8150-62T", "HPC-8151-62T" (manufactured by DIC Corporation); "EXB9401" (manufactured by DIC Corporation) as a phosphorus-containing active ester resin; "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin that is an acetylated phenol novolac; "YLH1026", "YLH1030", "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester resins that are benzoylated phenol novolacs; and "PC1300-02-65MA" (manufactured by Air Water Corporation) as an active ester resin containing a styryl group and a naphthalene structure.

[0192] The amount of the active ester resin is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 5% by mass or more, particularly preferably 11% by mass or more, preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, and particularly preferably 18% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition. When the amount of active ester resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and furthermore, the glass transition temperature, surface roughness, and adhesion of the cured product can usually be made particularly good.

[0193] The amount of the active ester resin is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, particularly preferably 35% by mass or more, preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, based on 100% by mass of the resin component of the resin composition. When the amount of the active ester resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and the glass transition temperature, surface roughness, and adhesion of the cured product can usually be made particularly good.

[0194] As phenolic resins, resins having one or more, preferably two or more, hydroxyl groups (phenolic hydroxyl groups) bonded to aromatic rings such as benzene rings and naphthalene rings per molecule can be used. From the viewpoint of heat resistance and water resistance, phenolic resins having a novolac structure are preferred. Furthermore, from the viewpoint of adhesion, nitrogen-containing phenolic resins are preferred, and triazine skeleton-containing phenolic resins are more preferred. Among these, triazine skeleton-containing phenol novolac resins are preferred from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion.

[0195] Specific examples of phenolic resins include "MEH-7700", "MEH-7810", "MEH-7851", and "MEH-8000H" from Meiwa Kasei Co., Ltd.; "NHN", "CBN", "GPH", and "GPH-65" from Nippon Kayaku Co., Ltd.; and "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", and "SN-495V" from Nippon Steel Chemical & Material Co., Ltd. Examples include "SN-375", "SN-395"; DIC Corporation's "TD-2090", "TD-2090-60M", "LA-7052", "LA-7054", "LA-1356", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", "TD-2090-60M"; and Gun-ei Chemical Co., Ltd.'s "GDP-6115L", "GDP-6115H", "ELPC75", etc.

[0196] The amount of phenolic resin is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition. When the amount of phenolic resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and the glass transition temperature, surface roughness, and adhesion of the cured product can usually be made particularly good.

[0197] The amount of phenolic resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, particularly preferably 3.5% by mass or more, preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and particularly preferably 5% by mass or less, based on 100% by mass of the resin component of the resin composition. When the amount of phenolic resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and furthermore, the glass transition temperature, surface roughness, and adhesion of the cured product can usually be made particularly good.

[0198] As carbodiimide resins, resins having one or more, preferably two or more, carbodiimide structures in one molecule can be used. Specific examples of carbodiimide resins include aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexanebis(methylene-t-butylcarbodiimide); biscarbodiimides such as aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylenebiscyclohexylenecarbodiimide), and poly(isophoronecarbodiimide); and poly(phenylenecarbodiimide), poly(na Examples of polycarbodiimides include aromatic polycarbodiimides such as phthalenecarbodiimide, poly(tylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylenediphenylenecarbodiimide), and poly[methylenebis(methylphenylene)carbodiimide]. Examples of commercially available carbodiimide resins include "Carbodilite V-02B," "Carbodilite A," "Carbodilite V-03," "Carbodilite V-04K," "Carbodilite V-05," "Carbodilite V-07," and "Carbodilite V-09" from Nisshinbo Chemical Co., Ltd., and "Stavaxol P," "Stavaxol P400," and "Hycazil 510" from Lanxess Corporation.

[0199] The amount of carbodiimide resin is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 2% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition. When the amount of carbodiimide resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and the glass transition temperature, surface roughness, and adhesion of the cured product can usually be made particularly good.

[0200] The amount of carbodiimide resin is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of the resin component of the resin composition. When the amount of carbodiimide resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and furthermore, the glass transition temperature, surface roughness, and adhesion of the cured product can usually be made particularly good.

[0201] As the cyanate resin, a resin having one or more, preferably two or more, cyanate groups in one molecule can be used. Examples of cyanate resins include bifunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl) thioether, and bis(4-cyanatephenyl) ether; polyfunctional cyanate resins derived from phenol novolacs and cresol novolacs; and prepolymers in which these cyanate resins are partially triazined. Specific examples of cyanate resins include "PT30" and "PT60" (phenol novolac type polyfunctional cyanate resins) manufactured by arxada, as well as "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate is triazined and trimerized).

[0202] As the benzoxazine resin, a resin having one or more, preferably two or more, benzoxazine rings in one molecule can be used. Specific examples of benzoxazine resins include "JBZ-OP100D" and "ODA-BOZ" from JFE Chemical Corporation; "HFB2006M" from Showa Polymer Co., Ltd.; and "Pd," "Fa," and "ALP-d" from Shikoku Chemicals, Inc.

[0203] As acid anhydride resins, resins having one or more, preferably two or more acid anhydride groups in one molecule can be used. Specific examples of acid anhydride resins include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexen-1,2-dicarboxylic acid anhydride, trimellitic anhydride, pyromellitic anhydride, and bensophenone tetracarboxylic acid di Examples include anhydrides, biphenyltetracarboxylic acid dianhydride, naphthalenetetracarboxylic acid dianhydride, oxydiphthalic acid dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymer-type acid anhydrides such as styrene-maleic acid resin obtained by copolymerizing styrene and maleic acid. Examples of commercially available acid anhydride resins include "HNA-100," "MH-700," "MTA-15," "DDSA," and "OSA" from Shin Nippon Rika Co., Ltd.; "YH-306" and "YH-307" from Mitsubishi Chemical Corporation; "HN-2200" from Resonaq Corporation; and "EF-30," "EF-40," "EF-60," and "EF-80" from Clay Valley Corporation.

[0204] As the amine resin, a resin having one or more, preferably two or more, amino groups in one molecule can be used. Examples of amine resins include aliphatic amines, polyetheramines, alicyclic amines, aromatic amines, etc., with aromatic amines being preferred. The amine resin is preferably a primary amine or a secondary amine, with primary amines being more preferred. Specific examples of amine resins include 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, and 2,2-bis(3-amino-4-hydroxyphenyl)propyl Examples include pan, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, etc. Examples of commercially available amine resins include "SEIKACURE-S" from Seika Corporation; "KAYABOND C-200S," "KAYABOND C-100," "KAYAHARD AA," "KAYAHARD AB," and "KAYAHARD AS" from Nippon Kayaku Co., Ltd.; "Epicure W" from Mitsubishi Chemical Corporation; and "DTDA" from Sumitomo Seika Co., Ltd.

[0205] Examples of thiol-based resins include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris(3-mercaptopropyl) isocyanurate.

[0206] The active group equivalent of the curing agent is preferably 50 g / eq. to 3,000 g / eq., more preferably 100 g / eq. to 1,000 g / eq., even more preferably 100 g / eq. to 500 g / eq., and particularly preferably 100 g / eq. to 300 g / eq. The active group equivalent represents the mass of resin per equivalent of active group. The active group of the curing agent refers to a group that can react with the epoxy group of the epoxy resin, such as an active ester group, a phenolic hydroxyl group, or a carbodiimide group.

[0207] The weight-average molecular weight (Mw) range of the curing agent may be the same as the weight-average molecular weight (Mw) range of the epoxy resin (A).

[0208] (A) The equivalent ratio (active groups / epoxy groups) of epoxy groups in the epoxy resin to active groups in the curing agent is preferably 0.1 or more, more preferably 0.5 or more, even more preferably 1.0 or more, preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less. The equivalent ratio (active groups / epoxy groups) can be determined by dividing the "number of active groups of the curing agent" in the resin composition by the "number of epoxy groups in (A) epoxy resin". The "number of epoxy groups in (A) epoxy resin" in the resin composition represents the sum of all values ​​obtained by dividing the mass of the non-volatile components of the epoxy resin present in the resin composition by their epoxy equivalents. The "number of active groups of the curing agent" in the resin composition represents the sum of all values ​​obtained by dividing the mass of the non-volatile components of the curing agent present in the resin composition by their active group equivalents. When the equivalent ratio (active group / epoxy group) is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and the glass transition temperature, surface roughness, and adhesion of the cured product can usually be made particularly good.

[0209] The amount of curing agent is preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition. When the amount of curing agent is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of the cured product can be particularly effectively improved, and furthermore, the glass transition temperature, surface roughness, and adhesion of the cured product can usually be made particularly good.

[0210] The amount of curing agent is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, based on 100% by mass of the resin component of the resin composition. When the amount of curing agent is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of the cured product can be particularly effectively improved, and the glass transition temperature, surface roughness, and adhesion of the cured product can usually be made particularly good.

[0211] (E) An example of an arbitrary curable resin is a radical polymerizable resin. A radical polymerizable resin contains non-aromatic carbon-carbon unsaturated bonds and can undergo radical polymerization reactions. Radical polymerizable resins may undergo radical polymerization reactions with other radical polymerizable resins, or they may undergo radical polymerization reactions with (B) maleimide resins.

[0212] As a radical polymerizable resin, for example, a resin containing polymerizable unsaturated groups can be used. A polymerizable unsaturated group represents a group containing a non-aromatic carbon-carbon unsaturated bond, and examples include unsaturated hydrocarbon groups such as vinyl group, allyl group, 1-propenyl group, 3-cyclohexenyl group, 3-cyclopentenyl group, 2-vinylphenyl group, 3-vinylphenyl group, and 4-vinylphenyl group; and α,β-unsaturated carbonyl groups such as acryloyl group and methacryloyl group. It is preferable that the radical polymerizable resin has two or more polymerizable unsaturated groups.

[0213] Examples of radical polymerizable resins include (meth)acrylic radical polymerizable resins, styrene radical polymerizable resins, and allyl radical polymerizable resins. Radical polymerizable resins may be used individually or in combination of two or more types.

[0214] As (meth)acrylic radical polymerizable resins, resins having one or more, preferably two or more acryloyl groups and / or methacryloyl groups per molecule can be used. Examples of (meth)acrylic radical polymerizable resins include cyclohexane-1,4-dimethanol di(meth)acrylate, cyclohexane-1,3-dimethanol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, and 1,9-nonane. Low molecular weight (molecular weight less than 1000) aliphatic (meth)acrylic acid ester compounds such as diol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, glycerin tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate; dioxaneglycol di(meth)acrylate, 3,6-dioxa-1,8-octanediol di(meth)acrylate; Examples include low molecular weight (molecular weight less than 1000) ether-containing (meth)acrylic acid ester compounds such as acrylate, 3,6,9-trioxaundecane-1,11-diol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, ethoxylated bisphenol A di(meth)acrylate, and propoxylated bisphenol A di(meth)acrylate; low molecular weight (molecular weight less than 1000) isocyanurate-containing (meth)acrylic acid ester compounds such as tris(3-hydroxypropyl) isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl) isocyanurate tri(meth)acrylate, and ethoxylated isocyanurate tri(meth)acrylate; and high molecular weight (molecular weight 1000 or more) acrylic acid ester compounds such as (meth)acrylic-modified polyphenylene ether resins. Here, the term "(meth)acrylic acid" includes acrylic acid, methacrylic acid, and combinations thereof.Furthermore, the term "(meth)acrylate" encompasses acrylate, methacrylate, and combinations thereof. Examples of commercially available (meth)acrylic radical polymerizable resins include "A-DOG" (dioxane glycol diacrylate) from Shin Nakamura Chemical Industry Co., Ltd., "DCP-A" (tricyclodecane dimethanol diacrylate), "DCP" (tricyclodecane dimethanol dimethacrylate), and "BPE-1300N" (ethoxylated bisphenol A dimethacrylate) from Kyoeisha Chemical Co., Ltd., "KAYARAD R-684" (tricyclodecane dimethanol diacrylate) and "KAYARAD R-604" (dioxane glycol diacrylate) from Nippon Kayaku Co., Ltd., and "SA9000" and "SA9000-111" (methacrylic modified polyphenylene ether) from SABIC Corporation.

[0215] As styrene-based radical polymerizable resins, resins having one or more, preferably two or more, vinyl groups directly bonded to aromatic carbon atoms in one molecule can be used. Examples of styrene-based radical polymerizable resins include low molecular weight (molecular weight less than 1000) styrene compounds such as divinylbenzene, 2,4-divinyltoluene, 2,6-divinylnaphthalene, 1,4-divinylnaphthalene, 4,4'-divinylbiphenyl, 1,2-bis(4-vinylphenyl)ethane, 2,2-bis(4-vinylphenyl)propane, and bis(4-vinylphenyl) ether; and high molecular weight (molecular weight 1000 or more) styrene compounds such as vinylbenzyl-modified polyphenylene ether resins and styrene-divinylbenzene copolymers. Examples of commercially available styrene-based radical polymerizable resins include "ODV-XET(X03)", "ODV-XET(X04)", and "ODV-XET(X05)" (styrene-divinylbenzene copolymer) from Nippon Steel Chemical & Material Co., Ltd., and "OPE-2St 1200" and "OPE-2St 2200" (vinylbenzyl-modified polyphenylene ether resin) from Mitsubishi Gas Chemical Co., Ltd.

[0216] As the allyl-based radical polymerizable resin, a resin having one or more, preferably two or more allyl groups per molecule can be used. Examples of allyl-based radical polymerizable resins include aromatic carboxylic acid allyl ester compounds such as diallyl diphenate, triallyl trimellitate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl 2,6-naphthalenedicarboxylic acid, and diallyl 2,3-naphthalenecarboxylic acid; isocyanurate allyl ester compounds such as 1,3,5-trialyl isocyanurate and 1,3-diallyl-5-glycidyl isocyanurate; ether-containing aromatic allyl compounds such as 1,3,5-trialyl etherbenzene; and allyl silane compounds such as diallyldiphenylsilane. Examples of commercially available allyl-based radical polymerizable resins include "TAIC" (1,3,5-triallyl isocyanurate) from Nippon Chemical Industries, Ltd., "DAD" (diallyl diphenate) from Nichishoku Techno Fine Chemicals Co., Ltd., "TRIAM-705" (triallyl trimellitate) from Fujifilm Wako Pure Chemical Corporation, "DAND" (2,3-diallyl naphthalenecarboxylate) from Nichishoku Techno Fine Chemicals Co., Ltd., and "ALP-d" (bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazine-3-yl)phenyl]methane) from Shikoku Chemicals, Ltd.

[0217] Radical polymerizable resins may contain active groups that can react with epoxy groups. Radical polymerizable resins containing active groups can function as both curing agents and radical polymerizable resins. Examples of resins that can function as both curing agents and radical polymerizable resins include resins containing both allyl groups and active ester groups, such as the active ester resin B and radical polymerizable resin A used in the examples described later.

[0218] The polymerizable unsaturated group equivalent of the radical polymerizable resin is preferably 20 g / eq. to 3,000 g / eq., more preferably 50 g / eq. to 2,500 g / eq., even more preferably 70 g / eq. to 2,000 g / eq., and particularly preferably 90 g / eq. to 1,500 g / eq. The polymerizable unsaturated group equivalent represents the mass of the resin per equivalent of polymerizable unsaturated groups.

[0219] The weight-average molecular weight (Mw) of the radical polymerizable resin is preferably 40,000 or less, more preferably 10,000 or less, even more preferably 5,000 or less, and particularly preferably 3,000 or less. The lower limit is not particularly limited, but may be, for example, 150 or more.

[0220] The amount of radical polymerizable resin is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, particularly preferably 4% by mass or more, preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and particularly preferably 8% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition. When the amount of radical polymerizable resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and furthermore, the glass transition temperature, surface roughness, and adhesion of the cured product can usually be made particularly good.

[0221] The amount of radical polymerizable resin is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, particularly preferably 15% by mass or more, preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 25% by mass or less, based on 100% by mass of the resin component of the resin composition. When the amount of radical polymerizable resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of its cured product can be particularly effectively improved, and furthermore, the glass transition temperature, surface roughness, and adhesion of the cured product can usually be made particularly good.

[0222] (E) The range of the amount of any curable resin is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition. (E) When the amount of any curable resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of the cured product can be particularly effectively improved, and the glass transition temperature, surface roughness and adhesion of the cured product can usually be made particularly good.

[0223] (E) The range of the amount of any curable resin is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, particularly preferably 40% by mass or more, preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 55% by mass or less, based on 100% by mass of the resin component of the resin composition. (E) When the amount of any curable resin is within the above range, the varnish stability of the resin composition and the insulation reliability and dielectric loss tangent of the cured product can be particularly effectively improved, and the glass transition temperature, surface roughness and adhesion of the cured product can usually be particularly good.

[0224] <(F) Polymer resin> The resin composition according to this embodiment may contain (F) a polymer resin as an optional component. The (F) polymer resin as component (F) does not include those corresponding to components (A) to (E) described above. The (F) polymer resin is usually thermoplastic. Furthermore, the (F) polymer resin is usually included in the resin composition in a compatible state with curable resins such as (A) epoxy resin and (B) maleimide resin, and is included in the cured product in that compatible state. The (F) polymer resin may be used alone or in combination of two or more types.

[0225] (F) Polymer resins typically have a large molecular weight. Specifically, the weight-average molecular weight Mw of (F) polymer resins is preferably greater than 5,000, more preferably 8,000 or more, even more preferably 10,000 or more, even more preferably 20,000 or more, preferably 100,000 or less, more preferably 70,000 or less, even more preferably 60,000 or less, and even more preferably 50,000 or less. The weight-average molecular weight Mw can be measured in polystyrene equivalent values ​​by gel permeation chromatography (GPC).

[0226] (F) Examples of polymer resins include phenoxy resin, polyimide resin, polyvinyl acetal resin, polystyrene resin, polyolefin resin, polybutadiene resin, polyamideimide resin, polyethersulfone resin, polysulfone resin, polyetherimide resin, polyphenylene ether resin, polycarbonate resin, polyetheretherketone resin, polyester resin, etc. Among these, phenoxy resin is preferred.

[0227] Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton. The ends of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Specific examples of phenoxy resins include "1256" and "4250" (both phenoxy resins containing the bisphenol A skeleton) manufactured by Mitsubishi Chemical Corporation; "YX8100" (phenoxy resin containing the bisphenol S skeleton) manufactured by Mitsubishi Chemical Corporation; "YX7800BH40" (phenoxy resin containing the fluorene skeleton) manufactured by Mitsubishi Chemical Corporation; and "YX6954" (phenoxy resin containing the bisphenolacetophenone skeleton) manufactured by Mitsubishi Chemical Corporation. Examples include: "FX280" and "FX293" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30", "YL6794", "YL7213", "YL7290", "YL7482", "YL7891BH30", "YL7891T30", and "YL9142T30" manufactured by Mitsubishi Chemical Corporation; and others.

[0228] Specific examples of polyimide resins include "PIAD200" manufactured by Arakawa Chemical Co., Ltd., "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., and "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin-Nippon Rika Co., Ltd. Other specific examples of polyimide resins include linear polyimide resins obtained by reacting a bifunctional hydroxyl-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride (polyimide resin described in Japanese Patent Publication No. 2006-37083), and modified polyimide resins containing a polysiloxane skeleton (polyimide resins described in Japanese Patent Publication No. 2002-12667 and Japanese Patent Publication No. 2000-319386, etc.).

[0229] Examples of polyvinyl acetal resins include polyvinyl formal resin and polyvinyl butyral resin, with polyvinyl butyral resin being preferred. Specific examples of polyvinyl acetal resins include S-Rec BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, BM series, etc., manufactured by Sekisui Chemical Co., Ltd.

[0230] Examples of polystyrene resins include unmodified polystyrene resin, oxazoline group-containing modified polystyrene resin, and styrene block copolymer. Examples of styrene block copolymers include styrene-isoprene-styrene block copolymer (SIS resin), styrene-ethylene-butylene-styrene block copolymer (SEBS resin), styrene-ethylene-propylene-styrene block copolymer (SEPS resin), styrene-butadiene-styrene block copolymer (SBS resin), and styrene-isobutylene-styrene block copolymer (SIBS resin). Specific examples of polystyrene resins include "PX3-RP-37" and "RP-RX-61" (oxazoline group-containing modified polystyrene resin) from Nippon Shokubai Co., Ltd.; and "HYBRAR" from Kuraray Co., Ltd. 5125 (SIS resin); Asahi Kasei's "S1611" (SEBS resin); Asahi Kasei's "H1041", "ToughTec H1043", "ToughTec P2000", "ToughTec MP10" (hydrogenated styrene polymer resin); Daicel's "Epofriend AT501", "CT310" (epoxidized styrene-butadiene polymer resin); Kuraray's "Septon HG252" (modified polystyrene resin with hydroxyl groups); Asahi Kasei's "ToughTec N503M" (modified polystyrene resin with carboxyl groups); Asahi Kasei's "ToughTec N501" (modified polystyrene resin with amino groups); Asahi Kasei's "ToughTec M1913" (modified polystyrene resin with acid anhydride groups); Kuraray's "Septon S8104" (unmodified polystyrene resin); Kraton's "FG1924" (styrene-ethylene / butylene-styrene block copolymer); "EF-40" (CRAY Examples include products manufactured by VALLEY Corporation.

[0231] Examples of polyolefin resins include ethylene-based copolymer resins such as low-density polyethylene, ultra-low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer; and polyolefin polymers such as polypropylene and ethylene-propylene block copolymer.

[0232] Examples of polybutadiene resins include hydrogenated polybutadiene skeleton-containing resins, hydroxyl group-containing polybutadiene resins, phenolic hydroxyl group-containing polybutadiene resins, carboxyl group-containing polybutadiene resins, acid anhydride group-containing polybutadiene resins, epoxy group-containing polybutadiene resins, isocyanate group-containing polybutadiene resins, urethane group-containing polybutadiene resins, and polyphenylene ether-polybutadiene resins.

[0233] Specific examples of polyamide-imide resins include "Viromax HR11NN" and "Viromax HR16NN" manufactured by Toyobo Co., Ltd. Other specific examples of polyamide-imide resins include modified polyamide-imides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamide-imide) manufactured by Hitachi Chemical Co., Ltd.

[0234] Specific examples of polyethersulfone resins include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

[0235] Specific examples of polysulfone resins include Solvay Advanced Polymers' polysulfones "P1700" and "P3500".

[0236] The polyphenylene ether resin may be, for example, a copolymer of polyphenylene ether and polybutadiene.

[0237] Specific examples of polyetherimide resins include GE's "Ultem," among others.

[0238] Examples of polycarbonate resins include hydroxyl group-containing carbonate resins, phenolic hydroxyl group-containing carbonate resins, carboxyl group-containing carbonate resins, acid anhydride group-containing carbonate resins, isocyanate group-containing carbonate resins, and urethane group-containing carbonate resins. Specific examples of polycarbonate resins include "FPC0220" from Mitsubishi Gas Chemical Co., Ltd., "T6002" and "T6001" (polycarbonate diols) from Asahi Kasei Corporation, and "C-1090," "C-2090," and "C-3090" (polycarbonate diols) from Kuraray Co., Ltd.

[0239] Specific examples of polyether ether ketone resins include "Sumiproi K" manufactured by Sumitomo Chemical Co., Ltd.

[0240] Examples of polyester resins include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, and polycyclohexanedimethyl terephthalate resin.

[0241] (F) The amount of polymer resin is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition.

[0242] (F) The range of the amount of polymer resin is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, preferably 10% by mass or less, preferably 5% by mass or less, and more preferably 2% by mass or less, based on 100% by mass of the resin component of the resin composition.

[0243] <(G)Organic filler> The resin composition according to this embodiment may contain (G) an organic filler as an optional component. The (G) organic filler does not include any of the components (A) to (F) described above. The (G) organic filler is usually miscible with curable resins such as (A) epoxy resin and (B) maleimide resin and is included in the resin composition in granular form, and is included in the cured product while maintaining that granular state. The (G) organic filler may be used alone or in combination of two or more types.

[0244] (G) As the organic filler, particles of organic material may be used. (G) As the organic material contained in the organic filler, rubber components are preferred. Examples of rubber components include silicone elastomers such as polydimethylsiloxane; olefin-based thermoplastic elastomers such as polybutadiene, polyisoprene, polychlorobutadiene, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-isobutylene copolymer, acrylonitrile-butadiene copolymer, isoprene-isobutylene copolymer, isobutylene-butadiene copolymer, ethylene-propylene-diene terpolymer, ethylene-propylene-butene terpolymer; and thermoplastic elastomers such as acrylic-based thermoplastic elastomers such as propyl poly(meth)acrylate, butyl poly(meth)acrylate, cyclohexyl poly(meth)acrylate, and octyl poly(meth)acrylate. Furthermore, silicone-based rubbers such as polyorganosiloxane rubber may be mixed with the rubber component. The rubber component contained in the rubber particles has a glass transition temperature of, for example, 0°C or lower, preferably -10°C or lower, more preferably -20°C or lower, and even more preferably -30°C or lower.

[0245] (G) The organic filler may be a core-shell type rubber particle consisting of core particles containing the rubber components listed above and a shell portion formed by graft copolymerization of monomer components copolymerizable with the rubber components contained in the core particles. Here, "core-shell type" does not necessarily refer only to those in which the core particles and shell portion can be clearly distinguished, but also includes those in which the boundary between the core particles and shell portion is unclear, and the core particles do not have to be completely covered by the shell portion.

[0246] (G)Specific examples of organic fillers include, for example, "CHT" from Samsung SDI; "B602" from Techno UMG; "Paraloid EXL-2602", "Paraloid EXL-2603", "Paraloid EXL-2655", "Paraloid EXL-2311", "Paraloid-EXL2313", "Paraloid EXL-2315", "Paraloid KM-330", "Paraloid KM-336P", "Paraloid KCZ-201" from Dow Corporation; and "Metablen C-223A", "Metablen E-" from Mitsubishi Rayon Corporation. Examples include "901", "Metablen S-2001", "Metablen W-450A", "Metablen SRK-200", Kaneka Corporation's "Kaneace M-511", "Kaneace M-600", "Kaneace M-400", "Kaneace M-580", "Kaneace MR-01", and Aica Kogyo Co., Ltd.'s "Stafiloid AC3355", "Stafiloid AC3816", "Stafiloid AC3816N", "Stafiloid AC3832", "Stafiloid AC4030", and "Stafiloid AC3364".

[0247] (G) The amount of organic filler is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 2% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition.

[0248] (G) The amount of organic filler is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, based on 100% by mass of the resin component of the resin composition.

[0249] <(H) Curing accelerator> The resin composition according to this embodiment may contain (H) a curing accelerator as an optional component. The (H) curing accelerator does not include any of the components (A) to (G) described above. The (H) curing accelerator can act as a catalyst in the reaction of curable resins such as (A) epoxy resin and (B) maleimide resin to accelerate the curing of the resin composition.

[0250] (H) Examples of curing accelerators include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, amine-based curing accelerators, etc. (H) A single type of curing accelerator may be used, or two or more types may be used in combination.

[0251] Examples of phosphorus-based curing accelerators include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium) pyromelitate, tetrabutylphosphonium hydrogen hexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butyldimethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, and tetraphenylphosphonium bromide. Aromatic phosphonium salts such as tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone addition products such as triphenylphosphine-p-benzoquinone addition products; aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine;Dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine Examples include aromatic phosphines such as tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, and 2,2'-bis(diphenylphosphino)diphenyl ether.

[0252] Examples of urea-based curing accelerators include aliphatic dimethylureas such as 1,1-dimethylurea, 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. Aromatic dimethylureas such as toluenebisdimethylurea, 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N',N'-dimethylurea), and N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluenebisdimethylurea] are examples.

[0253] Examples of guanidine-based curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]deca-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]deca-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

[0254] Examples of imidazole-based curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2- Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl -(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanurate adduct, 2-phenylimidazole isocyanurate adduct Examples of imidazole compounds include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins. Examples of commercially available imidazole-based curing accelerators include "1B2PZ", "2E4MZ", "2MZA-PW", "2MZ-OK", "2MA-OK", "2MA-OK-PW", "2PHZ", "2PHZ-PW", "Cl1Z", "Cl1Z-CN", "Cl1Z-CNS", and "C11Z-A" from Shikoku Chemicals, Inc., and "P200-H50" from Mitsubishi Chemical Corporation.

[0255] Examples of metal-based hardening accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organocobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organocopper complexes such as copper(II) acetylacetonate, organozinc complexes such as zinc(II) acetylacetonate, organoiron complexes such as iron(III) acetylacetonate, organonickel complexes such as nickel(II) acetylacetonate, and organomanganese complexes such as manganese(II) acetylacetonate. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0256] Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene. Commercially available amine-based curing accelerators may also be used, such as "MY-25" manufactured by Ajinomoto Fine Techno Co., Ltd.

[0257] (H) The amount of the curing accelerator is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition.

[0258] (H) The amount of the curing accelerator is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 1% by mass or more, preferably 10% by mass or less, more preferably 6% by mass or less, and even more preferably 3% by mass or less, based on 100% by mass of the resin component of the resin composition.

[0259] <(I) Any additives> The resin composition according to this embodiment may further contain (I) any additives as optional components. The (I) optional additives as components (I) do not include those corresponding to components (A) to (H) described above. Examples of (I) optional additives include organometallic compounds such as organocuber compounds, organozinc compounds, and organocobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium dioxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as bentonite and montmorillonite; defoaming agents such as silicone-based defoaming agents, acrylic-based defoaming agents, fluorine-based defoaming agents, and vinyl resin-based defoaming agents; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; and urea. Examples of additives include adhesion enhancers such as silanes; adhesion enhancers such as triazole-based adhesion enhancers, tetrazole-based adhesion enhancers, and triazine-based adhesion enhancers; antioxidants such as hindered phenol-based antioxidants; fluorescent whitening agents such as stilbene derivatives; surfactants such as fluorine-based surfactants and silicone-based surfactants; dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; and stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic acid anhydride-based stabilizers. (I) Any additive may be used alone or in combination of two or more types.

[0260] The resin composition according to this embodiment may (I) contain any cyclic phosphazene compound other than the above-mentioned (D) cyclic phosphazene compound as an optional additive. Examples of any cyclic phosphazene compound include cyclic phosphazene compounds having a structure other than the structure represented by formula (1). However, it is preferable that the resin composition according to this embodiment does not contain such any cyclic phosphazene compound. In particular, when the (D) cyclic phosphazene compound is a particle having an average particle diameter of 0.8 μm or more, it is preferable that the resin composition according to this embodiment does not contain any cyclic phosphazene compound.

[0261] Furthermore, the resin composition according to this embodiment may or may not contain phosphorus-based flame retardants other than (D) cyclic phosphazene compounds. The term "phosphorus-based flame retardant" means a flame retardant containing a phosphorus atom.

[0262] The resin composition according to this embodiment may or may not contain a poly(arylene ether) polymer containing monomer units including a pyrimidine, pyrazine, or pyridazine group. In other words, the resin composition according to this embodiment may be excluded if it contains a poly(arylene ether) polymer containing monomer units including a pyrimidine, pyrazine, or pyridazine group.

[0263] <(J) Solvent> The resin composition according to this embodiment may further contain a solvent (J) as a volatile component in combination with the non-volatile components such as components (A) to (I) described above. Typically, an organic solvent is used as the solvent (J). Examples of organic solvents include: ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, and anisole; alcohol solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; and 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples of solvents include ether ester solvents such as tyl; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene.

[0264] (J) The solvent may be used alone or in combination of two or more types. In particular, it is preferable that the solvent (J) includes a ketone solvent. When a ketone solvent is used, the varnish stability can be improved particularly effectively. The amount of the ketone solvent is preferably 20% by mass or more, more preferably 40% by mass or more, even more preferably 60% by mass or more, preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, based on 100% by mass of the total amount of the solvent (J). In particular, when the resin composition is a resin varnish, it is preferable that the amount of ketone solvent contained in the resin varnish is within the above range.

[0265] (J) The solvent preferably contains a high-boiling-point solvent having a boiling point of 100°C or higher. Examples of preferred high-boiling-point solvents include cyclohexanone (boiling point 155°C), methylcyclohexane (boiling point: 101°C), ethylcyclohexane (boiling point: 130-132°C), tetrahydronaphthalene (boiling point: 206-208°C), decahydronaphthalene (boiling point: 185-195°C), toluene (boiling point 111°C), methyl-n-amyl ketone (boiling point 151°C), 1-methoxy-2-propanol (boiling point 120°C), 2-methoxypropanol (boiling point 130°C), and the like. When a high-boiling-point solvent is used, the varnish stability can be improved particularly effectively. The amount of high-boiling-point solvent is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, based on 100% by mass of the total amount of solvent (J). In particular, when the resin composition is a resin varnish, it is preferable that the amount of high-boiling-point solvent contained in the resin varnish is within the above range.

[0266] In particular, the (J) solvent preferably contains a (J-1) non-aromatic high-boiling point solvent. A (J-1) non-aromatic high-boiling point solvent refers to a high-boiling point solvent that does not contain an aromatic ring in its molecule. Therefore, a (J-1) non-aromatic high-boiling point solvent refers to a solvent that does not contain an aromatic ring in its molecule and has a boiling point of 100°C or higher. Examples of (J-1) non-aromatic high-boiling point solvents include cyclohexanone, ethylcyclohexane, decahydronaphthalene, methyl amyl ketone, 1-methoxy-2-propanol, and 2-methoxypropanol. The amount of (J-1) non-aromatic high-boiling point solvent is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 5% by mass or more, even more preferably 10% by mass or more, and particularly preferably 13.3% by mass or more or 14% by mass or more, relative to 100% by mass of the total amount of (J) solvent, from the viewpoint of film flexibility, and preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, even more preferably 19% by mass or less, and even more preferably 18% by mass or less, relative to 100% by mass of the total amount of (J) solvent. The term "film flexibility" refers to the flexibility of the resin composition layer unless otherwise specified. Furthermore, the amount of (J-1) non-aromatic high-boiling point solvent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, particularly preferably 3% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, even more preferably 4.8% by mass or less, and even more preferably 4.7% by mass or less, relative to 100% by mass of the total amount of resin composition. In particular, when the resin composition is a resin varnish, it is preferable that the amount of high-boiling point solvent contained in the resin varnish is within the above range.

[0267] In particular, the mass ratio ((J-1) non-aromatic high-boiling solvent / (D) cyclic phosphazene compound) is preferably 1.0 or higher, more preferably 1.5 or higher, even more preferably 2.0 or higher, even more preferably 3.0 or higher, particularly preferably 4.5 or higher, preferably 15 or lower, more preferably 10 or lower, and even more preferably 8.0 or lower. When the mass ratio ((J-1) non-aromatic high-boiling solvent / (D) cyclic phosphazene compound) is within the above range, the varnish stability can be improved particularly effectively.

[0268] In one example, when solvent (J) contains cyclohexanone, the amount of cyclohexanone is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 5% by mass or more, and especially preferably 10% by mass or more, relative to 100% by mass of the total amount of solvent (J), from the viewpoint of film flexibility, and preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, relative to 100% by mass of the total amount of the resin composition. Furthermore, the mass ratio of cyclohexanone to (D)cyclic phosphazene compound (cyclohexanone / (D)cyclic phosphazene compound) is preferably 1.0 or higher, more preferably 1.5 or higher, even more preferably 2.0 or higher, particularly preferably 3.0 or higher, preferably 15 or lower, more preferably 10 or lower, and even more preferably 6.0 or lower.

[0269] In one example, when solvent (J) contains toluene, the amount of toluene is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 5% by mass or more, particularly preferably 10% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on 100% by mass of the total amount of solvent (J), from the viewpoint of resin compatibility and varnish stability. Also, the amount of toluene is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, particularly preferably 3% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of the total amount of the resin composition. Furthermore, the mass ratio of toluene to (D) cyclic phosphazene compound (toluene / (D) cyclic phosphazene compound) is preferably 1.0 or more, more preferably 1.5 or more, even more preferably 2.0 or more, particularly preferably 3.0 or more, preferably 15 or less, more preferably 10 or less, and even more preferably 6.0 or less.

[0270] When the resin composition according to this embodiment is a resin varnish, the amount of solvent (J) relative to 100% by mass of the total amount of the resin varnish is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less, and particularly preferably 30% by mass or less. A resin varnish containing an amount of solvent (J) in this range exhibits particularly excellent varnish stability.

[0271] On the other hand, when a resin composition layer is formed, the amount of solvent (J) contained in the resin composition layer is usually less than the amount of solvent (J) in the resin varnish. Specifically, the range of the amount of solvent (J) in the resin composition layer can be, for example, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, relative to 100% by mass of the resin composition. The lower limit may be 0% by mass, but it is usually greater than 0% by mass.

[0272] <Method for producing resin compositions> The resin composition according to this embodiment can be manufactured, for example, by mixing components that may be included in the resin composition. The above-mentioned components may be mixed some or all at the same time, or they may be mixed sequentially. The temperature may be set appropriately during the mixing of each component, and thus heating and / or cooling may be performed temporarily or throughout the process. Furthermore, stirring or shaking may be performed during the mixing of each component.

[0273] <Properties of resin compositions and their cured products> The resin composition according to this embodiment can have excellent varnish stability. Therefore, when the resin composition is a resin varnish, precipitation of components in the resin varnish due to storage can be suppressed. For example, when the resin composition is stored in a refrigerated environment (e.g., 4°C) for 3 days, the rate of increase in precipitates due to such storage can be preferably less than 1.5, more preferably less than 1.2. The rate of increase in precipitates can be measured by the method described in Test Example 1 of the Examples described later.

[0274] The resin composition according to this embodiment can preferably have high film flexibility. Therefore, the resin composition layer containing the resin composition according to this embodiment can preferably have high flexibility. In one example, the resin composition layer containing the resin composition can achieve a bending resistance of 100 or more times when subjected to a bending test under the conditions of a load of 2.5 N, a bending angle of 90°, a bending radius of 1.0 mm, and a bending speed of 175 times / min. The term "bending resistance" refers to the maximum number of times that repeated bending does not cause breakage. A specific method for measuring the bending resistance can be the method described in Test Example 6 of the Examples described later.

[0275] According to the resin composition of this embodiment, preferably, a resin composition layer having appropriate adhesion to a protective film can be obtained. Therefore, when a protective film is laminated to a resin composition layer containing the resin composition of this embodiment, unintended peeling of the protective film can be suppressed. More preferably, when the protective film is intentionally peeled off, the protective film can be peeled off smoothly. In one example, when a resin composition layer containing the resin composition is laminated to a protective film, the peel strength SB, which is the load required to peel the protective film from the resin composition layer, is preferably 0.003 kgf / cm or more, and preferably 0.006 kgf / cm or less. A specific method for measuring the peel strength SB can be the method described in Test Example 7 of the Examples described later.

[0276] By curing the resin composition according to this embodiment, a cured product of the resin composition can be obtained. This cured product can then be used to form a cured layer. Normally, heat is applied when curing a resin composition, so volatile components such as (J) solvents among the components contained in the resin composition may volatilize due to the heat during curing. Therefore, the cured product obtained by curing the resin composition may contain non-volatile components such as components (A) to (I) or their reaction products. The cured layer can be used, for example, as an insulating layer for a circuit board.

[0277] The cured product of the resin composition according to this embodiment can have excellent dielectric properties, specifically, a low dielectric loss tangent Df. In one example, the range of the dielectric loss tangent Df of the cured product is preferably 0.0040 or less, more preferably 0.0039 or less, even more preferably 0.0038 or less, and may be 0.0030 or less. There is no particular limit to the lower limit of the dielectric loss tangent Df, and it may be, for example, 0.0010 or more.

[0278] The dielectric loss tangent Df of the cured product can be measured by the cavity resonance perturbation method under measurement conditions of a measurement frequency of 5.8 GHz and a measurement temperature of 23°C. If the sample is a resin composition before curing, the resin composition may be cured at 190°C for 90 minutes to obtain a cured product, and the dielectric loss tangent Df of the cured product may be measured. For a specific measurement method, the method described in Test Example 2 of the Examples described later may be adopted.

[0279] The cured product of the resin composition according to this embodiment can have high insulation reliability. Specifically, after a storage test in which the cured product of the resin composition is stored for 300 hours under a voltage of 3.3V at a temperature of 130°C and a humidity of 85%RH, the cured product can have a high insulation resistance value. For example, when the insulation resistance value of the cured product is measured by the method described in Test Example 3 of the Examples described later, it is 1.0 × 10⁻⁶. 8 It is preferable that the insulation resistance value is Ω or greater. If the sample is a resin composition before curing, the resin composition may be cured at 200°C for 90 minutes to obtain a cured product, and the insulation reliability of the cured product may be evaluated.

[0280] The cured product of the resin composition according to this embodiment can usually have excellent heat resistance, and specifically, it can have a high glass transition temperature Tg. In one example, the range of the glass transition temperature Tg of the cured product is preferably 150°C or higher. The upper limit may be, for example, 300°C or lower, 250°C or lower, 200°C or lower, etc.

[0281] The glass transition temperature of the cured product can be measured by thermomechanical analysis using the tensile loading method under measurement conditions of a load of 1 g and a heating rate of 5 °C / min. If the sample is a resin composition before curing, the resin composition may be cured at 190 °C for 90 minutes to obtain a cured product, and the glass transition temperature Tg of the cured product may be measured. For a specific measurement method, the method described in Test Example 2 of the Examples described later may be adopted.

[0282] The cured product of the resin composition according to this embodiment can usually have a low surface roughness after roughening treatment. For example, when the cured product is subjected to desmear treatment by the method of Test Example 4 of the Examples described later, the range of the arithmetic mean roughness Ra of the surface of the cured product is preferably 300 nm or less, more preferably 200 nm or less, and even more preferably 100 nm or less. The lower limit may be, for example, 10 nm or more, 20 nm or more, 30 nm or more, etc. The arithmetic mean roughness Ra can be measured by the method of Test Example 4 of the Examples described later.

[0283] The cured resin composition according to this embodiment can usually exhibit excellent adhesion to the conductive layer formed on the cured material. For example, when a cured material layer is formed and a conductive layer is formed on the cured material layer by plating, the adhesion strength between the cured material layer and the conductive layer can be increased. The adhesion strength can be evaluated by the magnitude of the force required to peel the conductive layer from the cured material layer (plating peel strength). To give a specific example, when the plating peel strength between the insulating layer corresponding to the cured material layer and the conductive layer is measured by the method of Test Example 5 of the Examples described later, the plating peel strength is preferably 0.4 kgf / cm or more. The plating peel strength can be measured by the method of Test Example 5 of the Examples described later.

[0284] The resin composition and cured product thereof according to this embodiment are not particularly limited, but are usually not fibrous. That is, resin compositions and cured products thereof according to this embodiment can be excluded if they have a fibrous shape.

[0285] <Uses of resin compositions> The resin composition according to this embodiment can be used for forming insulating layers, and is particularly preferred for forming insulating layers on circuit boards. The resin composition may also be used for manufacturing resin sheets. Typically, insulating layers are formed using these resin sheets. Furthermore, the resin composition may be used for other applications, such as solder resist, underfill material, die bonding material, hole-filling resin, sealing resin, and component embedding resin. While the resin composition according to this embodiment is not particularly limited, it is generally not used for forming fibers. That is, fiber applications can be excluded from the uses of the resin composition according to this embodiment.

[0286] <Resin sheet> A resin sheet according to one embodiment of the present invention comprises a support and a resin composition layer formed on the support. The resin composition layer contains the above-mentioned resin composition, and preferably contains only the above-mentioned resin composition.

[0287] From the viewpoint of thinning, the thickness of the resin composition layer of the resin sheet is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. The lower limit of the thickness of the resin composition layer may be, for example, 1 μm or more, 3 μm or more, 5 μm or more, etc.

[0288] Examples of support materials include plastic film, metal foil, and release paper, with plastic film and metal foil being preferred.

[0289] When using a plastic film as a support, examples of plastic materials include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetylcellulose (TAC), polyether sulfide (PES), polyether ketones, and polyimides. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

[0290] When using metal foil as a support, examples of metal foil include copper foil and aluminum foil, with copper foil being preferred. As for copper foil, foil made of single-metal copper may be used, or foil made of an alloy of copper with another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used.

[0291] The support may have surface treatments such as matte finish, corona treatment, or antistatic treatment applied to the surface that bonds with the resin composition layer.

[0292] As the support, a support with a release layer may be used, which has a release layer on the surface that is bonded to the resin composition layer. Examples of release agents used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd-based release agents, polyolefin-based release agents, urethane-based release agents, and silicone-based release agents. Commercially available products may be used as the support with a release layer, for example, PET films having a release layer mainly composed of a silicone-based release agent or an alkyd resin-based release agent, such as "PET501010", "SK-1", "AL-5", and "AL-7" from Lintec Corporation; "Lumirror T60" from Toray Industries, Inc.; "Purex" from Teijin Ltd.; and "Unipeel" from Unitika Corporation.

[0293] The thickness of the support is not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, preferably 75 μm or less, more preferably 60 μm or less, and even more preferably 50 μm or less. When using a support with a release layer, it is preferable that the overall thickness of the support with the release layer is within the above range.

[0294] The resin sheet may include any components as needed. For example, the resin sheet may include a protective film to protect the resin composition layer. The protective film is usually provided on the side of the resin composition layer that is not bonded to the support (i.e., the side opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. When a protective film is provided, the adhesion of dust and scratches to the surface of the resin composition layer can be suppressed.

[0295] A resin sheet can be manufactured, for example, by a method that includes forming a resin composition layer on a support. Specifically, a resin sheet may be manufactured by applying a resin varnish as a resin composition onto a support and then drying it to form a resin composition layer.

[0296] The resin composition can be applied using a coating device such as a die coater. Drying can be carried out by drying methods such as heating or hot air blowing. The drying conditions are not particularly limited, but the solvent content in the resin composition layer is usually 10% by mass or less, preferably 5% by mass or less. Although this may vary depending on the boiling point of the solvent, for example, when using a resin composition containing 30% to 60% by mass of solvent, the resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0297] The manufactured resin sheets can be stored by rolling them up. If the resin sheets have a protective film, they can usually be used after removing the protective film.

[0298] <Circuit board> A circuit board according to one embodiment of the present invention includes a cured product of the resin composition described above. Typically, a circuit board has a cured product layer, and this cured product layer includes a cured product of the resin composition. The cured product layer may contain only a cured product of the resin composition. The cured product layer can be used as an insulating layer, such as an interlayer insulating layer. The thickness of the cured product layer is not particularly limited and can be, for example, in the same range as the thickness of the resin composition layer of a resin sheet. Furthermore, the cured product layer can usually have properties similar to those of the cured product of the resin composition described above.

[0299] Preferably, the circuit board comprises an inner layer substrate, and the cured material layer is provided on this inner layer substrate as an insulating layer. The circuit board may also comprise a conductive layer. For example, a conductive layer may be provided on the insulating layer. An example of a preferred method for manufacturing a circuit board will be described below.

[0300] A preferred example of a method for manufacturing a circuit board is: Step (I) of forming a resin composition layer on an inner layer substrate, (II) A step of curing the resin composition layer and Includes.

[0301] An "internal layer substrate" is a material that serves as the base for a circuit board, and examples include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, thermosetting polyphenylene ether substrates, etc. An internal layer substrate may have a conductive layer on one or both sides. The conductive layer on the internal layer substrate may be patterned. Circuit wiring can be formed using a patterned conductive layer. An internal layer substrate with conductive layers formed on one or both sides is sometimes called an "internal layer circuit board." Intermediate products on which an insulating layer and / or a conductive layer is further formed during the manufacturing of a circuit board are also included in the term "internal layer substrate." An internal layer substrate with embedded components may also be used.

[0302] From the viewpoint of taking advantage of the benefit of suppressing the formation of large particles due to the precipitation of components in the resin varnish, it is preferable that the minimum line and space (L / S) of the circuit wiring on the circuit board to which the resin composition according to the above embodiment is applied is small. Unless otherwise specified, "line" (L) represents the wiring width of the circuit wiring, and "space" (S) represents the spacing width between wirings. The range of the minimum line and space (L / S) is preferably 10 μm / 10 μm or less, more preferably 5 μm / 5 μm or less, even more preferably 3 μm / 3 μm or less, preferably 0.1 μm / 0.1 μm or more, more preferably 0.5 μm / 0.5 μm or more, and even more preferably 1 μm / 1 μm or more. In addition, the wiring pitch of the circuit wiring is preferably 20 μm or less, more preferably 10 μm or less, even more preferably 6 μm or less, preferably 0.2 μm or more, more preferably 1 μm or more, and even more preferably 2 μm or more. The line and space (L / S) and wiring pitch may be uniform or non-uniform throughout the entire conductor layer.

[0303] The formation of a resin composition layer on an inner layer substrate may be carried out by a formation method that includes, for example, applying a resin composition such as a resin varnish to the inner layer substrate and drying it as necessary, but it is preferable to use a resin sheet. The method for forming a resin composition layer using a resin sheet usually involves laminating the resin sheet and the inner layer substrate. The lamination of the resin sheet and the inner layer substrate is carried out so that the resin composition layer of the resin sheet and the inner layer substrate are joined. This lamination may be carried out, for example, by heating and pressing the resin sheet to the inner layer substrate from the support side. Examples of a member for heating and pressing the resin sheet to the inner layer substrate (hereinafter also referred to as the "heat-pressing member") include a heated metal plate (such as a SUS end plate) or a metal roll (such as a SUS roll). It is preferable to press the resin sheet via an elastic material such as heat-resistant rubber so that the resin sheet can sufficiently follow the surface irregularities of the inner layer substrate, rather than pressing the heat-pressing member directly onto the resin sheet.

[0304] Lamination of the inner layer substrate and the resin sheet may be carried out by a vacuum lamination method. In the vacuum lamination method, the heat-pressure temperature is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C, the heat-pressure pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably in the range of 0.29 MPa to 1.47 MPa, and the heat-pressure time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. Lamination is preferably carried out under reduced pressure conditions of 26.7 hPa or less.

[0305] Lamination may be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include vacuum pressure laminators manufactured by Meiki Seisakusho Co., Ltd., vacuum applicators manufactured by Nikko Materials Co., Ltd., and batch-type vacuum pressure laminators.

[0306] The method for manufacturing a circuit board may include, after lamination, a smoothing treatment of the resin sheet by pressing a heat-pressure bonding member from the support side under normal pressure (atmospheric pressure). The pressing conditions for the smoothing treatment may be the same as the conditions for the heat-pressure bonding of the lamination. The smoothing treatment can be performed using a commercially available laminator. Lamination and smoothing may be performed continuously using the commercially available vacuum laminator.

[0307] The method for manufacturing a circuit board according to this example includes a step (II) in which a resin composition layer is cured after step (I). By curing the resin composition layer in step (II), an insulating layer can be formed as a cured product layer containing the cured resin composition.

[0308] The resin composition layer is usually cured by thermal curing. The thermal curing conditions for the resin composition layer may vary depending on the type of resin composition. For example, the curing temperature is preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. The curing time may be preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 100 minutes.

[0309] The method for manufacturing a circuit board may include preheating the resin composition layer at a temperature lower than the curing temperature before the resin composition layer is heat-cured. For example, prior to heat-curing the resin composition layer, the resin composition layer may be preheated at a temperature of typically 50°C to 150°C, preferably 60°C to 140°C, more preferably 70°C to 130°C for typically 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes. Preheating is usually performed after step (I). Also, if a smoothing process is performed after lamination of the inner layer substrate and the resin sheet, preheating may usually be performed after the smoothing process.

[0310] When a resin sheet is used, the method for manufacturing the circuit board may include a step of peeling off the support of the resin sheet after lamination of the inner layer substrate and the resin sheet. The peeling off of the support may be performed between step (I) and step (II), or after step (II). Furthermore, if the method for manufacturing the circuit board includes a step of forming holes in the insulating layer (III), a step of roughening the insulating layer (IV), and a step of forming a conductor layer (V), as described later, the peeling off of the support may be performed between step (II) and step (III), between step (III) and step (IV), or between step (IV) and step (V).

[0311] The method for manufacturing a circuit board may include a step (III) after step (II) in which holes such as via holes and through holes are formed in the insulating layer. The method for forming the holes can be selected according to factors such as the composition of the resin composition used to form the insulating layer. For example, holes may be formed by processing methods such as drilling, laser processing, and plasma processing, with laser processing being preferred. For example, holes may be formed by irradiating the insulating layer with laser light after peeling off the support, or by irradiating the insulating layer with laser light through the support. The dimensions and shape of the holes may be appropriately determined according to the design of the circuit board.

[0312] A method for manufacturing a circuit board may include a step (IV) of roughening the insulating layer. The roughening treatment can roughen the surface of the insulating layer. Furthermore, the roughening treatment can remove smear (resin residue) from the insulating layer. For this reason, this roughening treatment is sometimes called "desmear treatment". For example, if holes are formed in step (III), smear may be formed inside those holes, so it is preferable to perform the roughening treatment in step (IV) after step (III) to remove the aforementioned smear.

[0313] The procedure and conditions for the roughening treatment are not particularly limited, and known procedures and conditions commonly used when forming the insulating layer of a circuit board can be employed. For example, the roughening treatment may be carried out by applying swelling treatment with a swelling solution, oxidation treatment with an oxidizing agent, and neutralization treatment with a neutralizing solution to the insulating layer in this order.

[0314] Examples of swelling solutions used for roughening treatment include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Sodium hydroxide solution and potassium hydroxide solution are more preferred as the alkaline solution. Examples of commercially available swelling solutions include "Swelling Dip Securigant P" and "Swelling Dip Securigant SBU" manufactured by Atotec Japan. Swelling treatment with a swelling solution can be carried out, for example, by immersing the insulating layer in a swelling solution at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing the swelling of the resin of the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in a swelling solution at 40°C to 80°C for 5 to 15 minutes.

[0315] Examples of oxidizing agents used in the roughening treatment include alkaline permanganate solutions obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The oxidation treatment with an oxidizing agent such as an alkaline permanganate solution is preferably carried out by immersing the insulating layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. Furthermore, the concentration of permanganate in the alkaline permanganate solution is preferably 5% to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigans P" manufactured by Atotec Japan.

[0316] As the neutralizing solution used for roughening treatment, an acidic aqueous solution is preferred, and a commercially available example is "Reduction Solution Securigant P" manufactured by Attec Japan. Neutralization treatment with a neutralizing solution can be carried out by immersing the treated surface, which has been oxidized with an oxidizing agent, in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the viewpoint of workability, it is preferable to immerse the object that has been oxidized with an oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

[0317] A method for manufacturing a circuit board may include a step (V) of forming a conductive layer on an insulating layer. If the method for manufacturing a circuit board includes step (III) or (IV), it is generally preferable that the step of forming the conductive layer (V) is performed after steps (III) and (IV).

[0318] The conductive material used in the conductive layer is not particularly limited. In a preferred embodiment, the conductive layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductive layer may be a single-metal layer or an alloy layer. Examples of alloy layers include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy). Among these, single-metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy are preferred from the viewpoint of versatility in conductive layer formation, cost, and ease of patterning, more preferred are single-metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, more preferred are single-metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, and even more preferred are single-metal layers of nickel-chromium alloy, with single-metal layers of copper being even more preferred.

[0319] The conductive layer may have a single-layer structure, or it may have a multi-layer structure including two or more single-metal layers or alloy layers made of different types of metals or alloys. When the conductive layer has a multi-layer structure, the layer in contact with the insulating layer is preferably a single-metal layer of chromium, zinc, or titanium, or an alloy layer of nickel-chromium alloy.

[0320] The thickness of the conductor layer depends on the design of the circuit board, but is preferably 3 μm to 35 μm, and more preferably 5 μm to 30 μm.

[0321] The conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer using conventionally known techniques such as the semi-additive method or the fully additive method. From the viewpoint of ease of manufacture, the semi-additive method is preferred. An example of forming the conductor layer by the semi-additive method is shown below.

[0322] First, an electroless plating layer (plating seed layer) is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern is formed on the formed electroless plating layer, exposing a portion of the electroless plating layer corresponding to the desired wiring pattern. After forming an electroplating layer on the exposed electroless plating layer by electroplating, the mask pattern is removed. Subsequently, the unnecessary electroless plating layer can be removed by etching to form a conductor layer having the desired wiring pattern.

[0323] As another example, the conductor layer may be formed using metal foil. When forming the conductor layer using metal foil, step (V) is preferably performed between steps (I) and (II). For example, after step (I), the support is removed and the metal foil is laminated onto the surface of the exposed resin composition layer. The lamination of the resin composition layer and the metal foil may be carried out by a vacuum lamination method. The lamination conditions may be the same as those described for step (I). Next, step (II) is performed to form an insulating layer. Subsequently, using the metal foil on the insulating layer, a conductor layer having a desired wiring pattern can be formed by known techniques such as the subtractive method or the modified semi-additive method. The metal foil can be manufactured by known methods such as the electrolytic method or the rolling method. Examples of commercially available metal foils include HLP foil and JXUT-III foil from JX Metals, and 3EC-III foil and TP-III foil from Mitsui Mining & Smelting Co., Ltd.

[0324] When a conductive layer is formed on an insulating layer, the method for manufacturing the circuit board may include annealing after the formation of the conductive layer. Annealing can improve the adhesion between the insulating layer and the conductive layer. Annealing can be performed, for example, by heating at 150°C to 210°C for 20 to 180 minutes.

[0325] In the method for manufacturing a circuit board, each of the above-described steps may be performed only once or repeated two or more times. For example, steps (I) to (V) may be repeatedly performed to form a circuit board having a multilayer structure, such as a multilayer printed wiring board, which comprises multiple insulating layers and conductive layers.

[0326] The method for manufacturing a circuit board may include any additional steps in addition to the steps described above. For example, the method for manufacturing a circuit board may include a step of providing a semiconductor chip so as to be bonded to a conductor layer. Specifically, when manufacturing a circuit board for a semiconductor chip package that includes a semiconductor chip, the method for manufacturing the circuit board may include a step of providing the semiconductor chip. The conditions for providing the semiconductor chip can be appropriate conditions that allow the terminal electrodes of the semiconductor chip and the conductor layer formed on the insulating layer to be conductively connected. For example, conditions used in flip-chip mounting may be used. The semiconductor chip may also be bonded via an insulating adhesive or by reflow soldering. Furthermore, if necessary, the provided semiconductor chip may be filled with mold underfill material. The method for manufacturing a circuit board may also include, for example, a step of forming a sealing layer, a step of forming a solder resist layer, and a step of dicing the manufactured circuit board into individual pieces.

[0327] Examples of circuit boards include printed circuit boards and semiconductor chip packages. Examples of semiconductor chip packages include FC-CSP, MIS-BGA packages, ETS-BGA packages, fan-out type WLP (Wafer Level Package), fan-in type WLP, fan-out type PLP (Panel Level Package), and fan-in type PLP. In these semiconductor chip packages, it is preferable to form a rewiring layer as an insulating layer using a cured product obtained by curing the above-mentioned resin composition. However, the circuit boards are not limited to those exemplified herein.

[0328] <Semiconductor device> The aforementioned circuit board can be used in the manufacture of semiconductor devices. The semiconductor device comprises the aforementioned circuit board. Examples of semiconductor devices include various types of semiconductor devices used in electrical products (e.g., computers, mobile phones, smartphones, tablet devices, wearable devices, digital cameras, medical equipment, and televisions, etc.) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft, etc.). [Examples]

[0329] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples. In the following explanation, "parts" and "%" refer to "parts by mass" and "% by mass," respectively, unless otherwise specified. Unless otherwise specified, the temperature and pressure conditions were room temperature (23°C) and atmospheric pressure (1 atm). In the following explanation, unless otherwise specified, Mw / Mn represents weight-average molecular weight / number-average molecular weight.

[0330] <First dissolution test and second dissolution test> To investigate the solubility of flame retardants such as the (D) cyclic phosphazene compounds used in the examples described later in relation to cyclohexanone, the following first and second dissolution tests were performed.

[0331] (First dissolution test) To 10 g of cyclohexanone, 0.5 g of the flame retardant (component (D) or (D')) used in each example was added, and ultrasonic treatment was performed for 10 minutes while heating at a measurement temperature of 25°C to dissolve the flame retardant. If the added flame retardant was completely dissolved in the cyclohexanone, another 0.5 g of flame retardant was added, and the ultrasonic treatment for 10 minutes was repeated. The addition of the flame retardant and ultrasonic treatment described above were repeated until the flame retardant no longer dissolved in the cyclohexanone and precipitates were observed. The cumulative amount of flame retardant added up to just before the point at which the flame retardant no longer dissolved in the cyclohexanone and precipitates were observed was determined as the amount of flame retardant dissolved.

[0332] (Second dissolution test) The amount of flame retardant dissolved in 10 g of cyclohexanone at 70°C was measured using the same method as in the first dissolution test described above, except that the measurement temperature was changed to 70°C.

[0333] <Synthesis Example 1: Synthesis of Liquid Epoxy Resin A> 100 g of 2,2-bis(4-hydroxy-3-methylphenyl)propane was dissolved in 1050 g of epichlorohydrin, and 0.25 g of benzyltriethylammonium chloride was added. Under reduced pressure at 70°C, 90 g of 48% aqueous sodium hydroxide solution was added dropwise over 5 hours. The water produced was removed from the system by azeotrope with the epichlorohydrin, and the precipitated epichlorohydrin was returned to the system. The reaction was continued for 2 hours after the dropwise addition, and then the salt produced was removed by filtration, followed by washing with water and distillation off the epichlorohydrin. The obtained epoxy resin was dissolved in 400 g of methyl isobutyl ketone, and 10 g of 10% aqueous sodium hydroxide solution was added at 85°C and the reaction was carried out for 2 hours. After the reaction, the mixture was filtered, washed with water, and distillation off the methyl isobutyl ketone to obtain 129 g of a mono-yellow liquid epoxy resin A. The epoxy resin A had a structure represented by the following formula (a-1) (wherein n is 0 to 5), and its epoxy group equivalent was 193 g / eq.

[0334] [ka]

[0335] <Synthesis Example 2: Synthesis of Maleimide Resin A> A MEK solution (70% by mass of non-volatile components) of maleimide resin A (Mw / Mn=1.81, u'=1.47 (mainly 1, 2, or 3)) represented by the following formula (b-4), synthesized by the method described in Synthesis Example 1 of the Japan Institute of Invention and Innovation Publication No. 2020-500211, was prepared.

[0336] [ka]

[0337] <Synthesis Example 3: Synthesis of Maleimide Resin B> (I) Synthesis of intermediate amine compound (c-1) In a flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, 400 g (3.3 mol) of 2-ethylaniline, 127 g of a compound having a benzyl ether skeleton (Nikanol L, manufactured by Fudo Co., Ltd.), 193 g of toluene, and 53 g of activated clay were charged. The mixture was heated to 120°C while stirring and held for 30 minutes. Then, the temperature was raised to 150°C and held for 3 hours. After the holding period, the temperature was raised to 200°C over 30 minutes and held for 10 hours. After the holding period, the mixture was diluted with 193 g of toluene, and the activated clay was filtered off. The solvent and excess 2-ethylaniline were removed from the filtrate by heating and reduced pressure to obtain the intermediate amine compound (c-1) (amine equivalent 209 g / equivalent).

[0338] (II) Maleimidization A 2L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer was charged with 73.2g (126mol, 1.3 equivalents) of maleic anhydride and 461g of toluene, and stirred at room temperature. Next, a mixed solution of 209g (1 equivalent) of intermediate amine compound (c-1) and 57.7g of N,N-dimethylformamide (DMF) was added dropwise over 1 hour, and the reaction was allowed to proceed for 2 hours. 9.72g of p-toluenesulfonic acid monohydrate was added to the reaction solution, and the solution was heated to 115°C. The azeotropic water and toluene were cooled and separated under reflux, and only toluene was returned to the system for dehydration for 5 hours. After air cooling to room temperature, the brown solution obtained by concentration under reduced pressure was dissolved in 600g of ethyl acetate and washed three times with 200g of deionized water and three times with 150g of 2% by mass sodium bicarbonate aqueous solution. After adding sodium sulfate and drying, the reaction product was concentrated under reduced pressure and vacuum-dried at 80°C for 4 hours to obtain maleimide resin B shown in the following formula (b-5). In the following formula (b-5), n represents an integer of 1 or more, and n 1 Each of these independently represents the number of repeating units, and Et represents the ethyl group.

[0339] [ka]

[0340] <Synthesis Example 4. Synthesis of Active Ester Resin B> A flask equipped with a thermometer, dropping funnel, condenser, fractionation column, and stirrer was charged with 165 g of polyaddition reaction resin for dicyclopentadiene and phenol (hydroxyl group equivalent: 165 g / eq., softening point 85°C), 134 g (1.0 mol) of orthoallylphenol, and 1200 g of toluene. The system was then purged with reduced pressure nitrogen. Next, 203 g (1.0 mol) of isophthalic acid chloride was charged, and the system was again purged with reduced pressure nitrogen. 0.6 g of tetrabutylammonium bromide was added, and while purging with nitrogen gas, the system temperature was controlled to below 60°C. 412 g of 20% sodium hydroxide aqueous solution was added dropwise over 3 hours, and after the addition was complete, the system was stirred for 1.0 hour. After the reaction was complete, the aqueous layer was removed by standing separatory. Water was added to the obtained toluene layer and stirred for 15 minutes, and the aqueous layer was removed by standing separatory. This procedure was repeated until the pH of the aqueous layer reached 7. Then, by adjusting the non-volatile components to 70% by mass through heat drying, an active ester resin B represented by the following formula (e-2) was obtained.

[0341] [ka]

[0342] <Synthesis Example 5: Synthesis of Active Ester Resin C> A flask equipped with a thermometer, dropping funnel, condenser, fractionation column, and stirrer was charged with 320 g (2.0 mol) of 2,7-dihydroxynaphthalene, 184 g (1.7 mol) of benzyl alcohol, and 5.0 g of p-toluenesulfonic acid monohydrate. The mixture was stirred at room temperature while blowing in nitrogen. The temperature was then raised to 150°C, and the mixture was stirred for 4 hours while distilling off the water produced. After the reaction was complete, 900 g of methyl isobutyl ketone and 5.4 g of 20% sodium hydroxide aqueous solution were added to neutralize the mixture. The aqueous layer was then removed by liquid-liquid extraction, and the mixture was washed three times with 280 g of water to remove the methyl isobutyl ketone under reduced pressure, yielding 460 g of benzyl-modified naphthalene compound (C'). The obtained benzyl-modified naphthalene compound (C') was a black solid with a hydroxyl group equivalent of 180 g / eq.

[0343] In a flask equipped with a thermometer, dropping funnel, condenser, fractionation column, and stirrer, 203.0 g of isophthalic acid chloride (2.0 moles of acid chloride groups) and 1400 g of toluene were charged, and the system was dissolved under reduced pressure and nitrogen purging. Next, 113.9 g (0.67 moles) of orthophenylphenol and 240 g of benzyl-modified naphthalene compound (C') (1.33 moles of phenolic hydroxyl groups) were charged, and the system was dissolved under reduced pressure and nitrogen purging. Subsequently, 0.70 g of tetrabutylammonium bromide was dissolved, and while purging with nitrogen gas, the system temperature was controlled to below 60°C, and 400 g of 20% sodium hydroxide aqueous solution was added dropwise over 3 hours. Then, under these conditions, stirring was continued for 1.0 hour to allow the reaction to proceed.

[0344] After the reaction was complete, the mixture was allowed to stand and separated, and the aqueous layer was removed. Furthermore, water was added to the toluene layer containing the dissolved reactants, and the mixture was stirred for 15 minutes. The mixture was then allowed to stand and separated, and the aqueous layer was removed. This procedure was repeated until the pH of the aqueous layer reached 7. Subsequently, water was removed by decanting to obtain an activated ester resin C in a toluene solution containing 62% by mass of non-volatile components. The structure of the obtained activated ester resin C is shown in formula (e-4) below. The equivalent amount of active ester groups in the obtained activated ester resin C was 238 g / eq.

[0345] [ka]

[0346] <Synthesis Example 6: Synthesis of Polyimide Resin A> A monomer mixture obtained by mixing 400 g of N,N-dimethylacetamide (hereinafter sometimes referred to as "DMAc") with 46.5 g of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (hereinafter sometimes referred to as "BPADA"), 50.4 g of 4,4'-[1,4-phenylenebis[(1-methylethylidene)-4,1-phenyleneoxy]]bisbenzeneamine (hereinafter sometimes referred to as "BPPAN"), 1.9 g of 5-norbornene-2,3-dicarboxylic acid anhydride, and 40 g of toluene was stirred and reacted at room temperature and atmospheric pressure for 3 hours. A polyamic acid solution was obtained by raising the temperature of the obtained polyamic acid solution and maintaining it at approximately 160°C while azeotropically removing condensed water with toluene under a nitrogen stream. It was confirmed that a predetermined amount of water had accumulated in the moisture meter and that no water outflow was observed. After confirmation, the reaction solution was further heated and stirred at 200°C for 1 hour. It was then cooled. This yielded a solution of polyimide resin A (20% by mass concentration of polyimide resin A).

[0347] <Synthesis Example 7: Synthesis of Polyimide Resin B> A monomer mixture obtained by mixing 46.5 g of BPADA, 37.8 g of BPPAN, 12.8 g of dimeramine (Cargill's "PRIAMINE 1075"), 1.9 g of 5-norbornene-2,3-dicarboxylic acid anhydride, and 40 g of toluene in 400 g of DMAc was stirred and reacted at room temperature and atmospheric pressure for 3 hours. This yielded a polyamic acid solution. A solution of polyimide resin B (20% by mass of polyimide resin B) was obtained by the same method as in Synthesis Example 6, except that the obtained polyamic acid solution was used in place of the polyamic acid solution used in Synthesis Example 6.

[0348] <Examples 1-21 and Comparative Examples 1-4> (1) Manufacturing of resin composition: Each component was weighed according to the formulations described in Tables 2 and 3 below, and 20 parts of MEK were added and uniformly dispersed using a high-speed rotary mixer to obtain a resin varnish as a resin composition. In the formulations described in Tables 2 and 3, the amounts of components (A) to (H) represent the amounts (parts by mass) of non-volatile components, and the amount of component (J), which is a solvent, represents the amount (parts by mass) of the solvent itself in relation to the total resin varnish. The details of each component described in Tables 2 and 3 are as follows.

[0349] (A) Epoxy resin: • NC3000L: Epoxy equivalent 271g / eq., manufactured by Nippon Kayaku Co., Ltd., biphenyl-type epoxy resin • YX4000H: Epoxy equivalent 194g / eq., manufactured by Mitsubishi Chemical Corporation, bisphenol skeleton epoxy resin HP6000L: Epoxy equivalent 213g / eq., manufactured by DIC Corporation, naphthalene-type epoxy resin HP7200L: Epoxy equivalent weight 246g / eq., manufactured by DIC Corporation, DCPD type epoxy resin. • ESN-475V: Epoxy equivalent weight 332g / eq., manufactured by Nippon Steel Chemical & Material Co., Ltd., naphthol aralkyl type epoxy resin • ESN-4100VEK75: Epoxy equivalent 363g / eq., manufactured by Nippon Steel Chemical & Material Co., Ltd., naphthol aralkyl type epoxy resin, MEK solution with 75% solids content. WHR-991S: Epoxy equivalent 266 g / eq., manufactured by Nippon Kayaku Co., Ltd., phenolphthalimidine type epoxy resin. • HP4032SS: Epoxy equivalent 144g / eq., manufactured by DIC Corporation, naphthalene-type epoxy resin. JER828: Epoxy equivalent 186g / eq., manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin • ZX-1059: Epoxy equivalent weight 165g / eq., manufactured by Nippon Steel Chemical & Material Co., Ltd., bisphenol A type epoxy resin • Liquid epoxy resin A: Epoxy equivalent 191 g / eq., Liquid epoxy resin A synthesized in Synthesis Example 1

[0350] (B-1) Aromatic maleimide resin: Maleimide resin A: Maleimide equivalent 428 g / eq., Maleimide resin B synthesized in Synthesis Example 2, MEK solution with 70% solids content. MIR-3000-70MT: Maleimide equivalent 393g / eq., manufactured by Nippon Kayaku Co., Ltd., MEK-toluene mixed solution with 70% solid content. • MIR-5000-60T: Maleimide equivalent 266 g / eq., manufactured by Nippon Kayaku Co., Ltd., toluene solution with 60% solids content. Maleimide resin B: 300 g / eq. maleimide equivalent, maleimide resin B synthesized in Synthesis Example 3, MEK solution with 75% solids content. • BMI-70: Maleimide equivalent 221g / eq., manufactured by K.I. Chemicals Co., Ltd. • BMI-80: Maleimide equivalent 285g / eq., manufactured by K.I. Chemicals Co., Ltd.

[0351] (B-2) Aliphatic maleimide resin: BMI-689: Maleimide equivalent 345g / eq., manufactured by Desinger Molecules Inc. • BMI-1500: Maleimide equivalent 752g / eq., manufactured by Desinger Molecules Inc. • BMI-3000: Maleimide equivalent 1500g / eq., manufactured by Desinger Molecules Inc.

[0352] (C) Inorganic filler: • SO-C2: Spherical silica manufactured by Admatex, with an average particle size of 0.5 μm, surface-treated with an amine-based silane coupling agent (Shin-Etsu Chemical Co., Ltd.'s "KBM573"). • LHP-208: Hollow silica manufactured by Ube Eximo Co., Ltd., with an average particle size of 0.5 μm, porosity of 50% by volume, and surface-treated with an amine-based silane coupling agent (KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.). • MG-005: Hollow silica manufactured by Taiheiyo Cement Corporation, with an average particle size of 1.6 μm, porosity of 80% by volume, and surface-treated with an amine-based silane coupling agent (KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0353] (D) Cyclic phosphazene compounds: • FP-72TP: A cyclic phosphazene compound represented by the following formula (d-1). It has a melting point above 280°C, a phosphorus content of 14.4%, a nitrogen content of 6.5%, an average particle size of 1 μm, a maximum particle size of 10 μm, and a dissolution amount of 0.00 g in 10 g of cyclohexanone at 25°C as measured in the first dissolution test, and a dissolution amount of 0.00 g in 10 g of cyclohexanone at 70°C as measured in the second dissolution test.

[0354] [ka]

[0355] FP-72TP pulverized product: A cyclic phosphazene compound with an average particle size of 0.7 μm and a maximum particle size of 5.0 μm.

[0356] (D') Any flame retardant: • HCA-HQ-HST: A flame retardant represented by the following formula (d'-2), manufactured by Sankosha, with a phosphorus content of 10% by mass and an average particle size of 1.5 μm. The amount dissolved in 10 g of cyclohexanone at 25°C, as measured in the first dissolution test, was 0.05 g, and the amount dissolved in 10 g of cyclohexanone at 70°C, as measured in the second dissolution test, was 0.40 g.

[0357] [ka]

[0358] • FP-100: Flame retardant, phosphorus content 13.4% by mass, manufactured by Fushimi Pharmaceutical Co., Ltd. The amount dissolved in 10g of cyclohexanone at 25°C, as measured in the first dissolution test, was 0.40g, and the amount dissolved in 10g of cyclohexanone at 70°C, as measured in the second dissolution test, was also 0.40g.

[0359] (E) Any curable resin: • Active ester resin C: Active ester group equivalent 238 g / eq., naphthalene-type active ester resin synthesized in Synthesis Example 5, toluene solution with 62% solids content. HP-C-8000L-65MT: Activated ester group equivalent 220g / eq., manufactured by DIC Corporation, activated ester resin, MEK-toluene mixed solution with 65% solids content. • Activated ester resin A: 250 g / eq. of activated ester group equivalent, activated ester resin represented by formula (e-1), toluene solution with 60% solids content.

[0360] [ka]

[0361] LA-3018-50P: Hydroxyl group equivalent 151 g / eq., manufactured by DIC Corporation, triazine skeleton-containing phenolic resin, 50% solids 1-methoxy-2-propanol solution. LA-1356: Hydroxyl group equivalent 146 g / eq., manufactured by DIC Corporation, triazine skeleton-containing phenolic resin SN-395: Hydroxyl group equivalent 110 g / eq., manufactured by DIC Corporation, naphthol aralkyl type phenolic resin GPH-65: Hydroxyl group equivalent 198g / eq., manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type phenolic resin • V-03: Active group equivalent 216 g / eq., manufactured by Nisshinbo Chemical Co., Ltd., carbodiimide resin, toluene solution with 50% solids content. • Active ester resin B: Active ester equivalent 214 g / eq., Active ester resin B synthesized in Synthesis Example 4, toluene solution with 70% solids content. • Radical polymerizable resin A: A radical polymerizable resin represented by the following formula (e-3), with an active ester group equivalent of 250 g / eq. and a solid content of 70% in a toluene solution.

[0362] [ka]

[0363] (F) Polymer resin: • YX7553BH30: Manufactured by Mitsubishi Chemical Corporation, phenoxy resin, MEK-cyclohexanone mixed solution with 30% solids content. • YL9142T30: Manufactured by Mitsubishi Chemical Corporation, phenoxy resin, toluene solution with 30% solids content. • PIAD200: A polyimide resin mixed solution of cyclohexanone, dimethyl glycol, and methylcyclohexane with a solid content of 30%, manufactured by Arakawa Chemical Co., Ltd. • Polyimide resin A: Polyimide resin A synthesized in synthesis example 6 • Polyimide resin B: Polyimide resin B synthesized in synthesis example 7

[0364] (G)Organic filler: • EXL-2655: A core-shell type cushion filler containing rubber components, manufactured by Dow Corporation.

[0365] (H) Curing accelerator: • 1B2PZ: Manufactured by Shikoku Chemicals Co., Ltd., imidazole-based curing accelerator, 10% solids MEK solution.

[0366] (J) solvent: • MEK: Methyl ethyl ketone • ECH: Ethylcyclohexane MCH: Methylcyclohexane • THNA: Tetrahydronaphthalene • DHNA: Decahydronaphthalene • MAK: Methylamylketone • Toluene: Toluene • 1-Methoxy-2-propanol: 1-Methoxy-2-propanol

[0367] <Test Example 1: Evaluation of Varnish Stability> The resin varnishes obtained in the examples and comparative examples were subjected to filtration to remove secondary aggregates of inorganic fillers and foreign matter from the resin varnish. The filtration method involved pumping the resin varnish using a metering pump and passing it through a mesh filter. The filtration pressure (differential pressure) was set to 0.4 MPa or less to prevent the mesh filter from opening. In addition, a metering pump with minimal pulsation was used to maintain a constant filtration pressure. The mesh size for filtration was 10 μm to 30 μm.

[0368] The filtered resin varnish was observed under an optical microscope, and the number (initial) of precipitates with a particle size of 10 μm or larger was measured. Next, the filtered resin varnish was stored in a refrigerator (4°C) for 3 days. The stored resin varnish was observed under an optical microscope, and the number of precipitates with a particle size of 10 μm or larger (after 3 days of refrigeration) was measured.

[0369] The rate of increase in precipitates was calculated using the following formula (M2). Growth rate = Number of precipitates (3 days refrigerated) / Number of precipitates (initial) (M2) Varnish stability was determined according to the following criteria. "Defective: Increase rate of precipitates is 1.5 or higher" "Good": The increase rate of precipitates is 1.2 or more but less than 1.5. "Excellent": Increase rate of precipitates is less than 1.2

[0370] <Test Example 2: Measurement of Dielectric Loss Tangent and Glass Transition Temperature> (1) Preparation of evaluation film: As a support film, a PET film (50 μm thick, 240 mm square) was prepared, having a release agent treated with Lintec's "1010" release agent on one side and an untreated side without the release agent. A glass cloth-based epoxy resin double-sided copper-clad laminate (Panasonic "R5715ES", 0.7 mm thick, 255 mm square) was placed on the untreated side of this support film, and the four sides were fixed with polyimide adhesive tape (10 mm wide).

[0371] The resin varnishes obtained in the examples and comparative examples were applied with an applicator to the release agent treated surface of the support film so that the thickness of the resin composition layer after drying was 40 μm, and dried at 70°C to 100°C (average 100°C) for 3 minutes. The glass cloth substrate epoxy resin double-sided copper-clad laminate was removed to obtain a resin sheet A comprising the support film and the resin composition layer.

[0372] (2) Preparation of cured samples for evaluation: Resin sheet A was placed in an oven at 190°C and heated for 90 minutes to heat-cur the resin composition layer. After heat curing, the PET film was peeled off to obtain a sheet-like cured product. The obtained cured product is referred to as the "evaluation cured product."

[0373] (3) Measurement of dielectric loss tangent: The cured material for evaluation was cut to obtain test specimens measuring 2 m in width and 80 mm in length. The dielectric loss tangent of these specimens was measured using a test apparatus (Agilent Technologies "HP8362B") by the cavity resonance perturbation method at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C. Measurements were performed on two specimens, and the average value was calculated.

[0374] (4) Measurement of the glass transition temperature: The hardened material for evaluation was cut to obtain test specimens approximately 5 mm wide and 15 mm long. Thermomechanical analysis was performed on these test specimens using a thermomechanical analyzer (Rigaku Corporation, "Thermo Plus TMA8310") with the tensile loading method. Specifically, after mounting the test specimens in the thermomechanical analyzer, thermomechanical analysis was performed twice consecutively under measurement conditions of a load of 1 g and a heating rate of 5 °C / min (the first time the temperature was raised to 200 °C, and the second time to 260 °C). The glass transition temperature was measured in the second thermomechanical analysis, and the evaluation was performed based on the following criteria. "Good": Glass transition temperature is 150°C or higher "Defective": Glass transition temperature is below 150°C

[0375] <Test Example 3: Insulation Reliability Test> An inner layer circuit board was prepared, comprising an imide film and a comb-shaped electrode (line and space (L / S) = 15 μm / 15 μm) formed on the imide film. This inner layer circuit board and the resin sheet A manufactured in Test Example 2 were laminated using a batch-type vacuum pressure laminator (Meiki Co., Ltd. "MVLP-500") so that the resin composition layer of resin sheet A was bonded to the comb-shaped electrode. Lamination was performed by reducing the pressure to 13 hPa or less for 30 seconds, and then pressing at 100°C and a pressure of 0.74 MPa for 30 seconds. The support film was peeled off. Subsequently, the resin composition layer was heat-cured at 200°C for 90 minutes to obtain an evaluation laminate having a layer structure of "inner layer circuit board / cured material layer".

[0376] The evaluation laminate was placed in an accelerated lifetime testing apparatus (PM422, manufactured by Kusumoto Chemical Co., Ltd.) and stored for 300 hours at a temperature of 130°C, a humidity of 85% RH, and a voltage of 3.3V. The insulation resistance of the cured layer was measured using the evaluation laminate after storage. The insulation resistance was 1.0 × 10⁻⁶. 8 If the resistance is Ω or higher, the insulation reliability is considered "good," and the insulation resistance value is 1.0 × 10⁻⁶. 8 Insulation reliability was rated as "poor" if the resistance was less than Ω.

[0377] <Test Example 4: Evaluation of roughness after wet desmearing> (1) Preparation of resin sheets: A polyethylene terephthalate film (AL5, manufactured by Lintec Corporation, 38 μm thick) with a release layer was prepared as a support. The resin varnish obtained in the examples and comparative examples was uniformly applied to the release layer of this support so that the thickness of the resin composition layer after drying was 25 μm, and the film was dried at 70°C to 80°C (average 75°C) for 2.5 minutes to obtain a resin sheet B including the support and the resin composition layer.

[0378] (2) Lamination of resin sheets: As an inner layer circuit board with copper foil on both sides, a glass cloth substrate epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.4 mm, Panasonic "R1515A") was prepared. The surfaces of the copper foil on both sides of the built-in circuit board were roughened using MEC's ​​"CZ8101" (copper etching amount 1.0 μm).

[0379] Using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd. 2-stage build-up laminator "CVP700"), resin sheet B was laminated to both sides of the inner circuit board so that the resin composition layer and the inner circuit board were bonded together. This lamination was performed by reducing the pressure to 13 hPa or less by depressurizing for 30 seconds, and then pressing at 120°C and a pressure of 0.74 MPa for 30 seconds. Subsequently, a hot press was performed at 100°C and a pressure of 0.5 MPa for 60 seconds.

[0380] (3) Thermosetting of the resin composition layer: Subsequently, the inner layer substrate laminated with resin sheet B was placed in a 130°C oven and heated for 30 minutes, then transferred to a 170°C oven and heated for another 30 minutes to heat-cur the resin composition layer and form an insulating layer. After that, the support was peeled off to obtain a cured substrate A having the insulating layer, inner layer substrate, and insulating layer in that order.

[0381] (4) Roughening treatment: A desmear treatment was performed on the cured substrate A as a roughening treatment. The following wet desmear treatment was carried out.

[0382] (Wet desmear treatment) Cured substrate A was immersed in a swelling solution (Atotec Japan's "Swelling Dip Securigant P," an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60°C for 5 minutes. Next, cured substrate A was immersed in an oxidizing agent solution (Atotec Japan's "Concentrate Compact CP," an aqueous solution with approximately 6% potassium permanganate and approximately 4% sodium hydroxide) at 80°C for 15 minutes. Next, cured substrate A was immersed in a neutralizing solution (Atotec Japan's "Reduction Solution Securigant P," an aqueous sulfuric acid solution) at 40°C for 5 minutes. After that, cured substrate A was dried at 80°C for 15 minutes. Cured substrate A subjected to this wet desmear treatment is referred to as "Evaluation Substrate B."

[0383] (5) Measurement of arithmetic mean roughness (Ra): The arithmetic mean roughness Ra of the insulating layer surface of evaluation substrate B was measured using a non-contact surface roughness meter (WYKO NT3300, B-Instruments). This measurement was performed in VSI mode with a 50x lens, and the measurement range was set to 121 μm × 92 μm. Measurements were taken at six points. The average value of the six points was calculated and rounded to the nearest tenth, as shown in the table below.

[0384] <Test Example 5: Evaluation of Plating Peel Strength> (1) Formation of the conductive layer: A conductive layer was formed on the roughened surface of the insulating layer of evaluation substrate B according to the semi-additive method. Specifically, evaluation substrate B, after roughening, was immersed in an electroless plating solution containing PdCl2 at 40°C for 5 minutes, and then immersed in an electroless copper plating solution at 25°C for 20 minutes to form an electroless plating layer. Next, evaluation substrate B was annealed by heating at 150°C for 30 minutes. After that, an etching resist was formed on the electroless plating layer, and a pattern was formed by etching. Subsequently, an electrolytic plating layer was formed on the electroless plating layer by copper sulfate electroplating. Through these operations, a conductive layer with a thickness of 25 μm, consisting of the electroless plating layer and the electrolytic plating layer, was formed on the roughened surface of the insulating layer. After that, an annealing treatment was performed at 180°C for 30 minutes to obtain "evaluation substrate C".

[0385] (2) Measurement of plating peel strength: The plating peel strength of the conductive layer and insulating layer was measured using the obtained evaluation substrate C. This measurement of plating peel strength was performed in accordance with JIS C6481. Specifically, the plating peel strength was measured by the following procedure.

[0386] A rectangular section measuring 10 mm wide and 100 mm long was cut into the conductive layer of evaluation substrate C. One end of this rectangular section was peeled off and grasped with a gripper (TSE Corporation's Autocom type testing machine "AC-50C-SL"). A 35 mm length section of this rectangular area was peeled vertically, and the load (kgf / cm) during this peeling was measured as the plating peel strength. The above peeling was performed at room temperature at a speed of 50 mm / min. A higher plating peel strength indicates better adhesion. Therefore, adhesion was judged according to the following criteria. "Good": Plating peel strength of 0.4 kgf / cm or higher. "Defective": Plating peel strength is less than 0.4 kgf / cm.

[0387] <Test Example 6: Evaluation Test of Film Flexibility> (1) Preparation of resin sheets for evaluation: As a support film, a PET film (50 μm thick, 240 mm square) was prepared, having a release agent treated with Lintec's "1010" release agent on one side and an untreated side without the release agent. A glass cloth-based epoxy resin double-sided copper-clad laminate (Panasonic "R5715ES", 0.7 mm thick, 255 mm square) was placed on the untreated side of this support film, and the four sides were fixed with polyimide adhesive tape (10 mm wide).

[0388] The resin varnishes obtained in the examples and comparative examples were applied with an applicator to the release agent treated surface of the support film so that the thickness of the dried resin composition layer was 40 μm, and dried at 70°C to 100°C (average 100°C) for 3 minutes. The glass cloth substrate epoxy resin double-sided copper-clad laminate was removed to obtain a resin sheet C comprising the support film and the resin composition layer.

[0389] (2) MIT exam: Resin sheet C was cut to obtain test specimens with a width of 15 mm and a length of 110 mm. A bending test was performed on these specimens using an MIT testing apparatus (MIT-DA bending fatigue tester, manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with JIS C-5016. In this bending test, resin sheet C was repeatedly bent under the following conditions: load of 2.5 N, bending angle of 90°, bending radius of 1.0 mm, and bending speed of 175 times / min. The number of bending cycles until the resin composition layer in resin sheet C broke was measured. Measurements were performed on 5 samples, and the average of the top 3 scores was calculated. Based on the calculated average value, the film flexibility was evaluated according to the following criteria. "Good": Withstands over 100 folds. "Defective": Withstands fewer than 100 folds.

[0390] <Test Example 7: Evaluation Test of Adhesion Between Resin Composition Layer and Protective Film> (1) Manufacturing of resin sheets with protective film: The resin sheet C obtained above was laminated with a long polypropylene film (Alfan MA-411, manufactured by Oji Specialty Paper Co., Ltd., 15 μm thick) as a protective film to produce a resin sheet with a protective film. The lamination was performed so that the surface of the resin composition layer of the resin sheet C and the smooth surface of the protective film were bonded together. The lamination was performed under normal pressure, at 60°C, and with a pressure of 0.06 kgf / cm². 2 It was carried out under the following conditions.

[0391] (2) Measurement of the peel strength of the protective film against the resin composition layer: The aforementioned resin sheet with protective film was cut to obtain a measurement sample measuring 30 mm in width and 100 mm in length. The cut was made so that the longitudinal direction of the protective film was parallel to the longitudinal direction of the measurement sample.

[0392] A 25mm wide, 95mm long double-sided tape (Nichiban Co., Ltd.'s "Nice Tack") was attached to the surface of the support film side of the obtained measurement sample. This double-sided tape was then bonded to a piece of paper cut to 27mm wide and 100mm long (Jitsut. Co., Ltd.'s high-grade thick paper "Konayuki 210 (extra thick)"). One end of the protective film was peeled off and grasped with a gripper. At room temperature (23℃), the protective film was pulled vertically at a speed of 50mm / min, and the load when the protective film was peeled off by 30mm was measured as the peel strength SB. A tensile tester (TSE Co., Ltd.'s "AC-50C-SL") was used for this measurement. Based on the measured peel strength SB, the adhesion between the resin composition layer and the protective film was evaluated according to the following criteria. "Excellent": Peel strength SB is 0.003 kgf / cm or more and 0.006 kgf / cm or less. "Good": Peel strength SB is greater than 0.006 kgf / cm "Defective": Peel strength SB is less than 0.003 kgf / cm

[0393] <Result> The results of the above-mentioned examples and comparative examples are shown in the table below. In the table below, the content (mass%) of components (A) to (H) indicates the ratio to 100% by mass of the non-volatile components of the resin varnish. The content (mass%) of methyl ethyl ketone, cyclohexanone, component (J-1), toluene, and 1-methoxy-2-propanol indicates the ratio to 100% by mass of the total amount of the resin varnish. The content (mass%) of component (J-1) in the total coating agent indicates the ratio to 100% by mass of the total coating agent. Furthermore, the meaning of the abbreviations is as follows. NV: Non-volatile component concentration MEK: Methyl ethyl ketone ECH: Ethylcyclohexane MCH: Methylcyclohexane THNA: Tetrahydronaphthalene DHNA: Decahydronaphthalene MAK: Methylamylketone Amount of flame retardant dissolved: Amount of flame retardant dissolved in cyclohexanone Df: Dielectric loss tangent Tg: Glass transition temperature Ra: Arithmetic mean (rough)

[0394] Table 2

[0395] Table 3

Claims

1. A resin composition comprising (A) epoxy resin, (B) maleimide resin, (C) inorganic filler, and (D) a cyclic phosphazene compound represented by the following formula (1), (C) A resin composition in which the amount of inorganic filler is 60% by mass or more relative to 100% by mass of the nonvolatile components of the resin composition. 【Chemistry 1】 (In equation (1), R １ and R ２ teeth, (i) Each independently, Nitro group, Alkyl or alkoxy groups having 1 to 8 carbon atoms, which may be substituted with at least one group selected from the group consisting of alkyl and aryl groups having 1 to 6 carbon atoms, An aryl group or aryloxy group having 6 to 20 carbon atoms may be substituted with at least one group selected from the group consisting of alkyl groups and aryl groups having 1 to 6 carbon atoms. It represents one of the following, or (ii) A saturated or unsaturated cyclic structure formed between them, which may be substituted with an alkyl or carbonyl group having 1 to 6 carbon atoms; L represents a divalent heteroatom; a and b each independently represent integers from 0 to 4; Each m independently represents either 0 or 1; n represents an integer from 3 to 8; The structure of each repeating unit is independent.

2. The resin composition according to claim 1, wherein the ratio of (B) maleimide resin to (A) epoxy resin ((B) maleimide resin / (A) epoxy resin) is 0.01 or more and 2.0 or less by mass.

3. The resin composition according to claim 2, wherein the ratio of (B) maleimide resin to (A) epoxy resin ((B) maleimide resin / (A) epoxy resin) is less than 0.6 by mass.

4. (A) The resin composition according to claim 1, wherein the amount of epoxy resin is 1% by mass or more and 30% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition.

5. (B) The resin composition according to claim 1, wherein the amount of maleimide resin is 0.1% by mass or more and 20% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition.

6. (C) The resin composition according to claim 1, wherein the amount of inorganic filler is 90% by mass or less with respect to 100% by mass of the nonvolatile components of the resin composition.

7. (D) The resin composition according to claim 1, wherein the amount of the cyclic phosphazene compound is 0.1% by mass or more and 5% by mass or less, based on 100% by mass of the nonvolatile components of the resin composition.

8. (D) The resin composition according to claim 1, wherein the amount of the cyclic phosphazene compound is 0.01% by mass or more and 5% by mass or less based on 100% by mass of the inorganic filler.

9. (D) The resin composition according to claim 1, wherein the cyclic phosphazene compound is a particle having an average particle diameter of 1.5 μm or less.

10. (D) The resin composition according to claim 1, wherein the cyclic phosphazene compound is a particle having an average particle diameter of 0.8 μm or less.

11. The resin composition according to claim 10, which does not contain any cyclic phosphazene compounds other than component (D).

12. The resin composition according to claim 10, wherein the resin composition is not fibrous.

13. (D) Cyclic phosphazene compounds are D ａ These are particles with an average particle diameter of μm. (C) The average particle size of the inorganic filler is D ｂ It is μm, D ａ / D ｂ The resin composition according to claim 1, wherein the ratio is 0.1 or more and 10 or less.

14. D ａ / D ｂ The resin composition according to claim 13, wherein the ratio is 1.5 or less.

15. (D) The resin composition according to claim 1, wherein the cyclic phosphazene compound has a melting point of 260°C or higher.

16. The resin composition according to claim 1, wherein when a first dissolution test is performed in which the cyclic phosphazene compound (D) is dissolved in 10 g of cyclohexanone by sonication at 25°C for 10 minutes, the amount of the cyclic phosphazene compound (D) dissolved is 0.04 g or less.

17. The resin composition according to claim 1, wherein when a second dissolution test is performed in which the cyclic phosphazene compound (D) is dissolved in 10 g of cyclohexanone by ultrasonic treatment at 70°C for 10 minutes, the amount of the cyclic phosphazene compound (D) dissolved is 0.3 g or less.

18. The resin composition according to claim 1, wherein the resin composition contains a ketone-based solvent.

19. The resin composition contains (J) a solvent, The resin composition according to claim 1, wherein the (J) solvent comprises a non-aromatic high-boiling point solvent that does not contain an aromatic ring in the (J-1) molecule and has a boiling point of 100°C or higher.

20. The resin composition according to claim 19, wherein the amount of (J-1) non-aromatic high-boiling point solvent is 20% by mass or less based on 100% by mass of the total amount of (J) solvent.

21. (J-1) The resin composition according to claim 19, wherein the amount of non-aromatic high-boiling point solvent is 4.8% by mass or less based on 100% by mass of the total amount of the resin composition.

22. (B) The resin composition according to claim 1, wherein the maleimide resin comprises an aromatic maleimide resin.

23. A support and a resin composition layer formed on the support, A resin sheet in which the resin composition layer comprises the resin composition according to any one of claims 1 to 22.

24. A cured product of the resin composition according to any one of claims 1 to 22.

25. A circuit board comprising a cured product of the resin composition according to any one of claims 1 to 22.

26. A semiconductor device comprising the circuit board described in claim 25.

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