Maleimide resin mixture, and curable resin composition and cured product thereof

Abstract

The present invention provides: a maleimide resin mixture which has an excellent low dielectric loss tangent and has excellent storage stability in a varnished form; and a curable resin composition and a cured product thereof.　The maleimide resin mixture comprises a maleimide resin having repeating units represented by formulae (a) and (b) and a maleimide resin represented by formula (c) and has an acid value of 15 or less.　(In formulae (a) and (b), Ra represents a hydrogen atom or a hydrocarbon group having 1-5 carbon atoms; m is the average number of repetitions and satisfies the formula 1 ≤ m < 200; n is the average number of repetitions and satisfies the formula 1.1 ≤ n < 100; and (a) and (b) are each bonded at *, wherein the repetition positions thereof may be random.)

Description

Maleimide resin mixture, curable resin composition, and cured product thereof

[0001] The present invention relates to a maleimide resin mixture, a curable resin composition, and a cured product thereof, and is suitably used for electrical and electronic components such as semiconductor encapsulation materials, printed wiring boards, build-up laminated boards, lightweight and high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, and 3D printing applications.

[0002] In recent years, due to the expansion of the fields of use, the required characteristics of laminated boards for mounting electrical and electronic components have become extensive and sophisticated. Conventionally, semiconductor chips were mainly mounted on metal lead frames, but semiconductor chips with high processing capabilities such as central processing units (hereinafter referred to as CPUs) are increasingly being mounted on laminated boards made of polymer materials.

[0003] In the currently accelerating development of the fifth-generation communication system "5G", further increases in capacity and high-speed communication are expected. In 5G, the frequency used will become higher, but in order to achieve high-speed communication using high frequencies, it is important to reduce transmission loss, and further low dielectric characteristics of the substrate material are required. The transmission loss occurring on a printed circuit board is derived from conductor loss and dielectric loss. As described in Non-Patent Document 1, since conductor loss is proportional to the square root of the relative permittivity and the dielectric tangent of the dielectric, it can be said that it is effective to improve the dielectric tangent with a higher contribution degree than the relative permittivity in order to reduce transmission loss. Examples of low dielectric materials include thermoplastic materials typified by PTFE (polytetrafluoroethylene) and LCP (liquid crystal polymer), but they have poor moldability compared to thermosetting resins. Based on this, the development of thermosetting resins with excellent low dielectric characteristics is desired. Specifically, the dielectric tangent at a frequency of 10 GHz at 25°C is preferably 0.0016 or less, and more preferably 0.0012 or less. These values are required by the market and correspond to the values of, for example, MEGTORON8 manufactured by Panasonic Corporation (see Panasonic Holdings Corporation press release "Development of 'Low Transmission Loss Multilayer Substrate Material MEGTRON8' for High-Speed Communication Network Equipment").

[0004] Furthermore, in order to meet the demands for miniaturization, thinning, and high density in semiconductor packages (hereinafter referred to as PKG) used in smartphones and other devices, there is a need to thin the PKG substrate. However, when the PKG substrate becomes thinner, its rigidity decreases, which can lead to problems such as significant warping due to the heating during soldering the PKG to the motherboard (PCB). To mitigate this, there is a need for PKG substrate materials with a high Tg (260°C) above the soldering temperature.

[0005] In light of this situation, maleimide resin has recently been considered as a printed circuit board material for high-frequency applications. Maleimide resin itself has the characteristic of high heat resistance due to its high crosslinking density, but as pointed out in Patent Document 1 below, bismaleimide compounds, which have an imide structure in their molecule, have high crystallinity and a high melting point of about 150°C, close to the 170-180°C that indicates the start of self-reaction. Therefore, it is a difficult material to prepare by impregnating with a varnish and drying it, or by melting and mixing it with epoxy resin, a curing agent, a filler, etc., to produce a molded material.

[0006] Signal Loss Factors in High-Speed ​​Signal Transmission on Printed Circuit Boards (Mitsui Mining & Smelting Co., Ltd.) 29th Spring Conference of the Japan Society for Electronics Packaging 16P1-17

[0007] Japanese Patent Publication No. 2018-12671, Japanese Patent No. 7534517

[0008] Patent Document 2 discloses a maleimide resin mixture that exhibits excellent low dielectric loss tangent, solvent solubility, and storage stability in varnish state by setting the content of component (C) in the total amount of the maleimide resin mixture to 5.0 to 30.0 area percent in terms of GPC area percentage. In other words, Patent Document 2 has the problem that the desired properties can only be obtained when the content of component (C) is 30 area percent or less.

[0009] This invention has been made in view of the above circumstances, and aims to provide a maleimide resin mixture, a curable resin composition, and a cured product thereof that exhibits excellent low dielectric loss tangent, solvent solubility, and storage stability in a varnish state.

[0010] The present invention relates to a maleimide resin mixture comprising a maleimide resin having repeating units of the following formulas (a) and (b), and a maleimide resin represented by the following formula (c), wherein the maleimide resin mixture has an acid value of 15 or less.

[0011]

[0012] (In the above formula, Ra represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms. m is the average number of repeats, where 1 ≤ m < 200. n is the average number of repeats, where 1.1 ≤ n < 100. (a) and (b) are bonded by *, and the repeat positions may be random.)

[0013]

[0014] In this application, "(numerical value 1) to (numerical value 2)" indicates that the upper and lower limits are included.

[0015] According to the present invention, it is possible to provide a maleimide resin mixture and a curable resin composition that exhibit excellent low dielectric loss tangent, solvent solubility, and storage stability in a varnish state.

[0016] The GPC chart for Example 1 is shown. The GPC chart for Example 2 is shown. The GPC chart for Comparative Example 1 is shown. The GPC chart for Comparative Example 2 is shown.

[0017] The embodiments of the present invention (hereinafter also referred to as "this embodiment") will be described in more detail below.

[0018] The maleimide resin mixture of this embodiment is a maleimide resin mixture comprising a maleimide resin having repeating units of the following formulas (a) and (b), and a maleimide resin represented by the following formula (c). Since the maleimide resin of this embodiment contains asymmetric alkyl substituents at the 2nd and 6th positions of the aromatic ring contained in the following formulas (b) and (c), it is possible not only to control the change in dielectric properties due to water absorption, but also to break down crystallinity and improve solvent solubility and solvent storage stability.

[0019]

[0020] In the above formula, Ra represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom. (a) and (b) are bonded by *, and the repeating positions may be random. m is the average value of the number of repeats, preferably 1 ≤ m < 200, more preferably 1 < m < 100, and particularly preferably 5 < m < 80. n is the average value of the number of repeats, more preferably 1.1 ≤ n < 100, even more preferably 1.1 ≤ n < 90, even more preferably 1.1 ≤ n < 80, and particularly preferably 1.1 ≤ n < 30. The values ​​of m and n are derived from the styrene monomer maleic anhydride copolymer, a raw material described later, and the values ​​of m and n can be determined from the ratio of styrene monomers and acid anhydrides and their molecular weight, which are determined from the acid value in the styrene monomer maleic anhydride copolymer.

[0021]

[0022] The acid value of the maleimide resin mixture of this embodiment can be measured by titration. The acid value is preferably 15 or less, more preferably 12 or less, and particularly preferably 10 or less. The lower limit of the acid value may be 0, but it is preferably 3 or more. The acid component in the maleimide resin mixture originates from unreacted styrene-based monomer malee anhydride copolymer, maleic anhydride, maleic acid as a by-product, and components containing the structure represented by the following formula (q) when the maleimide resin mixture of this embodiment was synthesized, and these components are factors that cause deterioration of dielectric properties. In addition, components containing the structure represented by the following formula (q) have poor solvent solubility in organic solvents, causing crystal precipitation and deterioration of storage stability.

[0023]

[0024] In the above formula, n and * have the same meaning as in formula (b) above.

[0025] In the total amount of the maleimide resin mixture of this embodiment, the content of the maleimide resin represented by formula (c) is preferably 5.0 area% to 50.0 area% in terms of GPC (gel permeation chromatography) area percentage, and more preferably 10.0 area% to 50.0 area%. In particular, the maleimide resin mixture of this embodiment is superior to the conventional technology in that it has excellent properties even in the range of more than 30.0 area% and 50.0 area% or less. When the maleimide resin content exceeds 50.0 area%, the dielectric properties deteriorate due to the increased proportion of maleimide groups, which are polar groups, and the maleimide resin represented by formula (c) precipitates as crystals, worsening the storage stability in the varnish state. Also, when the maleimide resin content is less than 5.0 area%, the proportion of maleimide groups that can be crosslinked decreases, worsening the curability and heat resistance.

[0026] The maleimide resin mixture of this embodiment can also be used to make a varnish by adding an organic solvent. Examples of organic solvents that can be used include toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. The varnish preferably contains 30 to 90% by weight of the maleimide resin mixture of this embodiment, and more preferably 40 to 80% by weight.

[0027] The method for producing the maleimide resin mixture of this embodiment is not particularly limited, but it can be obtained by reacting a styrene-based monomer maleic anhydride copolymer with 4,4-methylenebis(2-ethyl-6-methylaniline) and maleic anhydride. Specifically, it can be obtained by a first step of imidizing the styrene-based monomer maleic anhydride copolymer and 4,4-methylenebis(2-ethyl-6-methylaniline) in a solvent in the presence of a catalyst, followed by a second step of adding maleic anhydride and performing maleimidization. However, the order of the steps is not limited, and the order of the steps may be changed or performed simultaneously. Furthermore, after obtaining the maleimide resin mixture, the maleimide resin represented by formula (c) may be added and mixed in.

[0028] In the first step of imidization, gelation due to three-dimensional crosslinking during the reaction can be prevented by adding an excess of amino groups from the amine compound to 1 mole of acid anhydride contained in the styrene monomer maleic anhydride copolymer. In this case, the preferred range for the value (α / β) obtained by dividing the number of moles of amino groups (α) of the raw material amine by the number of moles of acid anhydride (β) of the styrene monomer maleic anhydride copolymer is 1.1 to 20, preferably 1.1 to 15, and more preferably 1.1 to 10. If the amine is smaller than the above range, gelation will occur, making production difficult. If it is larger than the above range, the amount of polystyrene introduced will decrease, and sufficient improvement in electrical properties cannot be expected. Examples of solvents that can be used include non-water-soluble solvents such as aromatic solvents such as toluene and xylene, aliphatic solvents such as cyclohexane and n-hexane, ethers such as diethyl ether and diisopropyl ether, ester solvents such as ethyl acetate and butyl acetate, and ketone solvents such as methyl isobutyl ketone and cyclopentanone, but are not limited to these, and two or more may be used in combination. In addition to the water-insoluble solvent, an aprotic polar solvent can also be used in combination. Examples include dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, and N-methylpyrrolidone, and two or more may be used in combination. When using an aprotic polar solvent, it is preferable to use one with a higher boiling point than the water-insoluble solvent used in combination. During the reaction, if necessary, hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, p-toluenesulfonic acid, methanesulfonic acid, as well as Lewis acids such as aluminum chloride and zinc chloride, solid acids such as activated clay, acid clay, white carbon, zeolite, and silica alumina, and acidic ion exchange resins may be used as catalysts. These may be used alone or in combination of two or more. The amount of catalyst used is usually 0.1 to 0.8 moles per mole of amino groups of the amine compound used, preferably 0.2 to 0.7 moles. Using too much catalyst may increase the viscosity of the reaction solution, making stirring difficult, while using too little may slow down the reaction.In the second step of imidation, the remaining amine can be completely maleimidized by adding maleic anhydride in an amount equivalent to or greater than the number of moles of amino groups of the amine charged in excess in the first step, preferably 1.1 equivalents or more. A basic co-catalyst such as triethylamine can also be used alone or in combination as a co-catalyst for imidation. If a sulfonic acid is used as a catalyst, neutralization with an alkali metal such as sodium hydroxide or potassium hydroxide may be performed before proceeding to the extraction step. The solid content concentration during the reaction is preferably 45-75%. If the solid content concentration is too low, the reaction rate will be poor, and unreacted acid anhydride groups will remain, resulting in a high acid value and deterioration of dielectric properties. On the other hand, if it is too high, the raw materials may not dissolve, or the viscosity may become too high, making stirring difficult.

[0029] For the extraction process, aromatic hydrocarbon solvents such as toluene or xylene may be used alone, or non-aromatic hydrocarbons such as cyclohexane or toluene may be used in combination. After extraction, it is preferable to wash the organic layer with water until the wastewater becomes neutral, and then wash it again with a mixed solution of water and a water-soluble organic solvent. This step improves the separation during water washing and further reduces impurities such as amic acid, thereby lowering the acid value. Examples of water-soluble organic solvents that can be used include alcohols such as methanol, ethanol, 1-propanol, 2-methyl-2-propanol, 1-butanol, and isobutyl alcohol, as well as 1,2-dimethylethane, triethylamine, pyridine, and acetic acid. By distilling off the solvent from the organic layer after washing using an evaporator or the like, a maleimide resin having a polystyrene structure within the molecule can be obtained.

[0030] Styrene monomer-maleic anhydride copolymers are obtained by copolymerizing styrene monomers and maleic anhydride. Any known polymerization method may be used, including radical polymerization, coordination polymerization, and various living polymerization methods. For example, they can be obtained by reacting styrene monomers and maleic anhydride in toluene in the presence of a radical polymerization initiator. The resulting polymer may be a random polymer, a periodic copolymer, a block polymer, or an alternating copolymer. The stereoregularity of the polystyrene segments may be syndiotactic, atactic, isotactic, etc. It is particularly preferable that the styrene monomer-maleic anhydride copolymer is a styrene-maleic anhydride copolymer.

[0031] The weight-average molecular weight (Mw) of the styrene monomer maleic anhydride copolymer, as determined by gel permeation chromatography (GPC), is preferably 900 or more and less than 10,000, more preferably 1,500 or more and less than 9,000, and particularly preferably 2,000 or more and less than 8,000. The number-average molecular weight (Mn) is preferably 1,000 or more and less than 5,000, and more preferably 1,000 or more and less than 3,000. If the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are below the above upper limits, gelation can be prevented, and purification by washing with water becomes easier. If the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are above the above lower limits, the target compound will not volatilize during the solvent removal process.

[0032] The weight-average molecular weight (Mw) of the maleimide resin mixture of this embodiment, as determined by gel permeation chromatography (GPC), is preferably 1,000 or more and less than 100,000, more preferably 1,000 or more and less than 7,000, and particularly preferably 2,000 or more and less than 6,000. The number-average molecular weight (Mn) is preferably 1,000 or more and less than 5,000, and more preferably 1,000 or more and less than 2,000. It is preferable that the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are below the above upper limits because they have excellent solvent solubility. It is also preferable that they are above the above lower limits because they result in less volatile matter during molding and are less likely to cause molding defects.

[0033] The maleimide equivalent of the maleimide resin mixture of this embodiment can be determined by potentiometric titration. The maleimide equivalent of the maleimide resin mixture of this embodiment is preferably 300 g / eq or more and less than 3000 g / eq, more preferably 300 g / eq or more and less than 2000 g / eq, and particularly preferably 300 g / eq or more and less than 1500 g / eq. It is preferable that the maleimide equivalent is below the above upper limit because it contains maleimide groups, which are crosslinking components, and can be incorporated into the curing network, reducing molding defects and increasing the glass transition temperature (Tg). It is also preferable that it is above the above lower limit because there are fewer highly polar maleimide groups in the cured product, allowing for control over changes in properties due to water absorption.

[0034] The curable composition of this embodiment may contain a polymerization inhibitor in addition to the maleimide resin mixture of this embodiment. The inclusion of a polymerization inhibitor improves storage stability and allows control of the reaction initiation temperature. Controlling the reaction initiation temperature facilitates fluidity, prevents impregnation into glass cloth and other materials, and facilitates B-stage processes such as prepreg formation. If the polymerization reaction proceeds too far during prepreg formation, problems such as difficulty in lamination during the lamination process are likely to occur. Examples of usable polymerization inhibitors include phenolic, sulfuric, phosphorusic, hindered amine, nitroso, and nitroxyl radical-based polymerization inhibitors. The polymerization inhibitor may be added during the synthesis of the maleimide resin mixture of this embodiment or after synthesis. Furthermore, the polymerization inhibitor can be used alone or in combination of two or more types. The amount of polymerization inhibitor used is usually 0.008 to 1 part by weight, preferably 0.01 to 0.5 parts by weight, per 100 parts by weight of the resin component. These polymerization inhibitors can be used individually, but two or more types may also be used in combination. In this embodiment, phenolic, hindered amine, nitroso, and nitroxyl radical types are preferred.

[0035] Specific examples of phenolic polymerization inhibitors include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-p-ethylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3, Monophenols such as 5-di-t-butylanilino)-1,3,5-triazine, 2,4-bis[(octylthio)methyl]-o-cresol; 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), Triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxyhydrocinnamamide), 2,2-thiodiethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl Bisphenols such as )propionate, 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 3,9-bis[1,1-dimethyl-2-{β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane, and bis(3,5-di-t-butyl-4-hydroxybenzylsulfonate ethyl)calcium;Examples of high molecular weight phenols include 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, tris-(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, and tocopherol.

[0036] Specific examples of sulfur-based polymerization inhibitors include dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, and distearylul-3,3'-thiodipropionate.

[0037] Specific examples of phosphorus-based polymerization inhibitors include triphenyl phosphite, diphenylisodecyl phosphite, phenyldiisodecyl phosphite, tris(nonylphenyl) phosphite, diisodecylpentaerythritol phosphite, tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis(octadecyl) phosphite, cyclic neopentanetetraylbi(2,4-di-t-butylphenyl) phosphite, and cyclic neopentanetetraylbi(2,4-di-t-butyl-4-methylphenyl) phosphite. Examples include phosphites such as bis[2-t-butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl]hydrogen phosphite; and oxaphosphaphenanthrene oxides such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0038] Specific examples of the hindered amine polymerization inhibitor include, but are not limited to, AdekaStab LA-40MP, AdekaStab LA-40Si, AdekaStab LA-402AF, AdekaStab LA-87, DecaStab LA-82, DecaStab LA-81, AdekaStab LA-77Y, AdekaStab LA-77G, AdekaStab LA-72, AdekaStab LA-68, AdekaStab LA-63P, AdekaStab LA-57, AdekaStab LA-52, Chimassorb 2020FD L, Chimassorb 944FD L, Chimassorb 944LD, Tinuvin 622SF, Tinuvin PA144, Tinuvin 765, Tinuvin 770DF, Tinuvin XT55FB, Tinuvin 111FD L, Tinuvin 783FD L, Tinuvin 791FB, etc.

[0039] Specific examples of the nitroso polymerization inhibitor include p-nitrosophenol, N-nitrosodiphenylamine, ammonium salt of N-nitrosophenylhydroxyamine (cupferron), etc., and preferably, ammonium salt of N-nitrosophenylhydroxyamine (cupferron).

[0040] Specific examples of the nitroxyl radical polymerization inhibitor include, but are not limited to, di-tert-butyl nitroxide, 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-acetoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl, etc.

[0041] In the curable resin composition of the present embodiment, any known material can be used as a curable resin other than the maleimide resin mixture of the present embodiment. Specifically, maleimide resins other than the maleimide resin mixture of the present embodiment, phenol resins, epoxy resins, amine resins, compounds containing ethylenically unsaturated bonds, isocyanate resins, polyamide resins, polyimide resins, cyanate ester resins, propenyl resins, methallyl resins, active ester compounds, polyphenylene ether compounds, benzoxazine compounds, etc. can be mentioned, and they may be used alone or in combination of multiple kinds. Also, from the balance of heat resistance, adhesion, and dielectric properties, it is preferable to contain an epoxy resin, a compound containing an ethylenically unsaturated bond, and a cyanate ester resin. By containing these curable resins, the brittleness of the cured product can be improved and the adhesion to metal can be enhanced, and the package cracks in reliability tests such as solder reflow and thermal cycling can be suppressed. The amount of the above curable resin used is preferably in a weight range of 10 times by weight or less, more preferably 5 times by weight or less, still more preferably 3 times by weight or less, and particularly preferably 1 time by weight or less, relative to the maleimide resin mixture of the present embodiment. Also, the preferable lower limit value is 0.1 times by weight or more, more preferably 0.25 times by weight or more, still more preferably 0.5 times by weight or more, and particularly preferably 0.5 times by weight or more. If it is 10 times by weight or less, the effects of the heat resistance and dielectric properties of the maleimide resin mixture of the present embodiment can be utilized.

[0042] As maleimide resins, phenol resins, epoxy resins, amine resins, compounds containing ethylenically unsaturated bonds, isocyanate resins, polyamide resins, polyimide resins, cyanate ester resins, and active ester resins other than the maleimide resin mixture of the present embodiment, those exemplified below can be used.

[0043] Maleimide resins other than the maleimide resin mixture of this embodiment: 4,4'-diphenylmethanebismaleimide, polyphenylmethanemaleimide, m-phenylenebismaleimide, 2,2'-bis[4-(4-maleimidophenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, 4,4'-diphenyletherbismaleimide, 4,4'-diphenylsulfonebismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4 - Maleimide phenoxybenzene), Zyloc-type maleimide compounds (anilix maleimide, manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenyl aralkyl-type maleimide compounds (solidified by solvent distillation under reduced pressure of a resin solution containing the maleimide compound (M2) described in Example 4 of Japanese Patent Publication No. 2009-001783), bisaminocumylbenzene-type maleimide (maleimide compound described in International Publication No. 2020 / 054601), maleimide compounds having an indan structure described in Japanese Patent No. 6629692 or International Publication No. 2020 / 217679, MATERIAL STAGE Vol. 18, No. 12 2019 "Continued Epoxy Resin CAS Number Story - Curing Agent CAS Number Memo No. 31 Bismaleimide (1)" and MATERIAL STAGE Vol. 19, No. 2. Maleimide compounds described in "Continued Story of Epoxy Resin CAS Numbers - Memorandum on Hardener CAS Numbers, Part 32: Bismaleimide (2)" (2019).

[0044] Phenolic resins: Phenolic resins are compounds having two or more phenolic hydroxyl groups in their molecules. Examples of phenolic resins include, but are not limited to, reaction products of phenols and aldehydes, reaction products of phenols and diene compounds, reaction products of phenols and ketones, reaction products of phenols and substituted biphenyls, reaction products of phenols and substituted phenyls, and reaction products of bisphenols and aldehydes. Furthermore, these may be used individually or in combination of multiple types. Specific examples of the above raw materials are given below, but are not limited to these. <Phenols> Phenol, alkyl-substituted phenol, aromatic-substituted phenol, hydroquinone, resorcinol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc. <Aldehydes> Formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural, etc. <Diene Compounds> Dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc. <Ketones> Acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, fluorenone, etc. <Substitutive biphenyls> 4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, 4,4'-bis(hydroxymethyl)-1,1'-biphenyl, etc. <Substitutive phenyls> 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene, etc.

[0045] Polyphenylene ether compound: Any known polyphenylene ether compound may be used, but from the viewpoint of heat resistance and electrical properties, it is preferable to use a polyphenylene ether compound having an ethylenically unsaturated double bond, and more preferably a polyphenylene ether compound having an acrylic group, a methacrylic group, or a styrene structure. Commercially available products include SA-9000-111 (manufactured by SABIC, a polyphenylene ether compound having a methacrylic group), OPE-2St 1200, and OPE-2St 2200 (manufactured by Mitsubishi Gas Chemical Co., Ltd., a polyphenylene ether compound having a styrene structure). The number average molecular weight (Mn) of the polyphenylene ether compound is preferably 500 to 5000, more preferably 2000 to 5000, and even more preferably 2000 to 4000. If the molecular weight is less than 500, the heat resistance of the cured product tends not to be sufficient. Furthermore, if the molecular weight is greater than 5000, the melt viscosity increases, and sufficient fluidity cannot be obtained, which tends to lead to molding defects. Also, reactivity decreases, requiring a long time for the curing reaction, and the amount of unreacted material that is not incorporated into the curing system increases, lowering the glass transition temperature of the cured product and reducing the heat resistance of the cured product. If the number average molecular weight of the polyphenylene ether compound is between 500 and 5000, it is possible to exhibit excellent heat resistance and moldability while maintaining excellent dielectric properties. The number average molecular weight here can be specifically measured using gel permeation chromatography or the like.

[0046] The polyphenylene ether compound may be obtained by polymerization or by redistributing a high molecular weight polyphenylene ether compound with a number average molecular weight of about 10,000 to 30,000. Alternatively, these can be used as raw materials and reacted with compounds having ethylenically unsaturated double bonds, such as methacrylic chloride, acrylic chloride, and chloromethylstyrene, to impart radical polymerizability. The polyphenylene ether compound obtained by redistribution is, for example, obtained by heating a high molecular weight polyphenylene ether compound in a solvent such as toluene in the presence of a phenolic compound and a radical initiator to redistribute it. Polyphenylene ether compounds obtained by this redistribution reaction are preferable because they have hydroxyl groups derived from phenolic compounds that contribute to hardening at both ends of the molecular chain, thus maintaining even higher heat resistance, and because functional groups can be introduced to both ends of the molecular chain even after modification with a compound having ethylenically unsaturated double bonds. Furthermore, polyphenylene ether compounds obtained by polymerization are preferable because they exhibit excellent fluidity.

[0047] The molecular weight of polyphenylene ether compounds can be adjusted by adjusting polymerization conditions, etc., in the case of polyphenylene ether compounds obtained by polymerization reactions. In the case of polyphenylene ether compounds obtained by redistribution reactions, the molecular weight of the resulting polyphenylene ether compound can be adjusted by adjusting the conditions of the redistribution reaction, etc. More specifically, this can be done by adjusting the amount of phenolic compound used in the redistribution reaction. That is, the higher the amount of phenolic compound used, the lower the molecular weight of the resulting polyphenylene ether compound. In this case, poly(2,6-dimethyl-1,4-phenylene ether) can be used as the high molecular weight polyphenylene ether compound that undergoes the redistribution reaction. Furthermore, the phenolic compound used in the redistribution reaction is not particularly limited, but polyfunctional phenolic compounds having two or more phenolic hydroxyl groups in the molecule, such as bisphenol A, phenol novolac, and cresol novolac, are preferably used. These may be used individually or in combination of two or more.

[0048] Furthermore, while the content of the polyphenylene ether compound is not particularly limited, it is preferably 10 to 90% by weight, and more preferably 20 to 80% by weight, relative to the total weight of the curable resin components. A polyphenylene ether compound content of 10 to 90% by weight is preferable not only because it provides excellent heat resistance, but also because it yields a cured product that fully exhibits the excellent dielectric properties of the polyphenylene ether compound.

[0049] Epoxy resin: The following are examples of preferred epoxy resins, but are not limited to these. The epoxy resin may be liquid or solid, and may be used alone or in combination of multiple types.

[0050] Examples of liquid epoxy resins include bisphenol A 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, glycidylamine type epoxy resin, and epoxy resin having a butadiene structure. Specific examples include "RE310S", "RE410S" (both manufactured by Nippon Kayaku Co., Ltd., bisphenol A type epoxy resin), "RE303S", "RE304S", "RE403S", "RE404S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy resin), "HP-4032", "HP-4032D", "HP-4032SS" (all manufactured by DIC Corporation, naphthalene type epoxy resin), "jER(registered trademark) 828US", "jER828EL", "jER825", "jER828EL" (all manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin), "jER807", "jER1750" (both manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin), and "jER152" (Mitsubishi Chemical Corporation). Examples include: "JER630" and "JER630LSD" (both manufactured by Mitsubishi Chemical Corporation, glycidylamine type epoxy resins), "ZX1059" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin), "EX-721" (manufactured by Nagase ChemteX Corporation, glycidyl ester type epoxy resin), "Celoxide 2021P" (manufactured by Daicel Corporation, alicyclic epoxy resin with an ester skeleton), "PB-3600" (manufactured by Daicel Corporation, epoxy resin with a butadiene structure), "ZX1658" and "ZX1658GS" (both manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., liquid 1,4-glycidylcyclohexane type epoxy resins). These may be used individually or in combination of two or more types.

[0051] Preferred solid epoxy resins include, for example, bixylenol-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type tetrafunctional 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, and tetraphenylethane-type epoxy resin.Specific examples include "HP4032H" (manufactured by DIC Corporation, naphthalene-type epoxy resin), "HP-4700", "HP-4710" (both manufactured by DIC Corporation, naphthalene-type tetrafunctional epoxy resin), "N-690" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), "N-695" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (both manufactured by DIC Corporation, dicyclopentadiene-type epoxy resin), "EXA-7311", "EXA-7311- "G3", "EXA-7311-G4", "EXA-7311-G4S", "HP-6000" (all manufactured by DIC Corporation, naphthylene ether type epoxy resin), "EPPN-502H" (manufactured by Nippon Kayaku Co., Ltd., trisphenol type epoxy resin), "NC-7000L", "NC-7300" (both manufactured by Nippon Kayaku Co., Ltd., naphthol-cresol novolac type epoxy resin), "NC-3000H", "NC-3000", "NC-3000L", "NC-3100" (all manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin) "XD-1000-2L", "XD-1000-L", "XD-1000-H" (all manufactured by Nippon Kayaku Co., Ltd., dicyclopentadiene type epoxy resin), "ESN475V" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., naphthol type epoxy resin), "ESN485" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., naphthol novolac type epoxy resin), "YX-4000H", "YX-4000", "YL6121" (all manufactured by Mitsubishi Chemical Corporation, biphenyl type epoxy resin), "YX-4000HK" (manufactured by Mitsubishi Chemical Corporation, bixylenol type epoxy resin), Examples include "YX-8800" (manufactured by Mitsubishi Chemical Corporation, anthracene-type epoxy resin), "PG-100", "CG-500" (manufactured by Osaka Gas Chemical Co., Ltd., fluorene-type epoxy resin), "YL-7760" (manufactured by Mitsubishi Chemical Corporation, bisphenol AF-type epoxy resin), "YL-7800" (manufactured by Mitsubishi Chemical Corporation, fluorene-type epoxy resin), "jER1010" (manufactured by Mitsubishi Chemical Corporation, solid bisphenol A-type epoxy resin), and "jER1031S" (manufactured by Mitsubishi Chemical Corporation, tetraphenylethane-type epoxy resin). These may be used individually or in combination of two or more types.

[0052] Amine resins: Amine resins are compounds that have two or more amino groups in their molecule. Examples of amine resins include diaminodiphenylmethane, diaminodiphenylsulfone, isophoronediamine, naphthalenediamine, aniline novolac (reaction product of aniline and formalin), N-methylaniline novolac (reaction product of N-methylaniline and formalin), orthoethylaniline novolac (reaction product of orthoethylaniline and formalin), reaction product of 2-methylaniline and formalin, reaction product of 2,6-diisopropylaniline and formalin, reaction product of 2,6-diethylaniline and formalin, reaction product of 2-ethyl-6-ethylaniline and formalin, reaction product of 2,6-dimethylaniline and formalin, and those obtained by the reaction of aniline with xylylene chloride. Examples of aniline resins include, but are not limited to, aniline and substituted biphenyls (such as 4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl) as described in Japanese Patent Publication No. 6429862, aniline and substituted phenyls (such as 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene), 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, aniline and diisopropenylbenzene, and dimer amines. Furthermore, these may be used individually or in combination.

[0053] Compounds containing ethylenically unsaturated bonds: Compounds containing ethylenically unsaturated bonds are compounds that have one or more ethylenically unsaturated bonds in their molecule, which can be polymerized by heat or light, regardless of whether a polymerization initiator is used or not. Examples of compounds containing ethylenically unsaturated bonds include the reaction products of the phenol resin and halogenated compounds containing ethylenically unsaturated bonds (chloromethylstyrene, allyl chloride, methallyl chloride, acrylate chloride, methacrylate chloride, etc.), and phenols containing ethylenically unsaturated bonds (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) and halogenated compounds (1,4-bis(chloromethyl)benzene, 4,4'-bis( Reaction products of chloromethyl)biphenyl, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuryl chloride, etc.; reaction products of epoxy resins or alcohols with (meth)acrylic acids (acrylic acid, methacrylic acid, etc.) and acid-modified products thereof; poly(arylene ether) polymers (HC-G0037, HC-G0024, HC-G0030, HC-G0038, all manufactured by JSR Corporation. These may contain monomer units containing pyridazine, pyrimidine, or pyrazine groups.) Reaction products of fluorenes or indenes with halogen compounds containing ethylenically unsaturated bonds (chloromethylstyrene, allyl chloride, methyl chloride, acrylate chloride, methacrylate chloride, etc.), compounds described in Japanese Patent No. 6951829, copolymers containing divinylbenzene as a constituent unit (ODV-XET(X3), ODV-XET(X4), ODV-XET(X5), all manufactured by Nippon Steel Chemical & Material Co., Ltd.), styrene, vinyltoluene, ethyl vinylbenzene Examples include, but are not limited to, benzene, vinylnaphthalene, vinylbiphenyl, vinylfluorene, divinylbenzene, divinylnaphthalene, divinylbiphenyl, divinylfluorene, BVPM (bis(vinylphenyl)methane), BVPE (bis(vinylphenyl)ethane), BVPH (bis(vinylphenyl)hexane), trivinylcyclohexane, and thermosetting cycloolefin copolymers (Mitsui Chemicals: GigaFreak, Zeon Corporation: TU-01A). These can be used individually or in combination.

[0054] Isocyanate resin: An isocyanate resin is a compound that has two or more isocyanate groups in its molecule. Examples of isocyanate resins include, but are not limited to, aromatic diisocyanates such as p-phenylenediisocyanate, m-phenylenediisocyanate, p-xylenediisocyanate, m-xylenediisocyanate, 2,4-tollylenediisocyanate, 2,6-tollylenediisocyanate, 4,4'-diphenylmethanediisocyanate, and naphthalenediisocyanate; aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylenediisocyanate, 4,4'-dicyclohexylmethanediisocyanate, hydrogenated xylenediisocyanate, norbornene diisocyanate, and lysine diisocyanate; polyisocyanates such as one or more isocyanate monomers or isocyanate compounds obtained by trimerizing the above diisocyanate compounds; and polyisocyanates obtained by urethane reaction between the above isocyanate compounds and polyol compounds. Furthermore, these can be used individually or in combination.

[0055] Polyamide resins: Examples of polyamide resins include reaction products of one or more of diamines, diisocyanates, or oxazolines with dicarboxylic acids, reaction products of diamines and acid chlorides, and ring-opening polymers of lactam compounds. These may be used individually or in combination. Specific examples of the above raw materials are given below, but are not limited to these.<Diamines> Ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-diaminopentane, 2-methyl 1,8-diaminooctane, dimer amine, cyclohexanediamine, bis-(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, xylylenediamine, norbornanediamine, isophoronediamine, bisaminomethyltricyclodecane, phenylenediamine, diethyltoluenediamine, naphthalenediamine, diaminodiphenylmethane, bis(4-amino-3,5-dimethylphenyl)methane, bis(4-amino-3,5-diethylphenyl)methane 4,4'-methylenebis-o-toluidine, 4,4'-methylenebis-o-ethylaniline, 4,4'-methylenebis-2-ethyl-6-methylaniline, 4,4'-methylenebis-2,6-diisopropylaniline, 4,4-ethylenedianiline, diaminodiphenylsulfone, diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-amino [phenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, 9,9-bis(4-aminophenyl)fluorene, 2,7-diaminofluorene, aminobenzylamine, diaminobenzophenone, etc.<Diisocyanates> Benzene diisocyanate, toluene diisocyanate, 1,3-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)cyclohexane, bis(4-isocyanatophenyl)methane, isophorone diisocyanate, 1,3-bis(2-isocyanato-2-propyl)benzene, 2,2-bis(4-isocyanatophenyl)hexafluoropropane, dicyclohexylmethane-4,4'-diisocyanate, etc. <Dicarboxylic acids> Oxalic acid, malonic acid, succicic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanediic acid, dodecanediic acid, terephthalic acid, isophthalic acid, 5-hydroxyisophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, cyclohexanedicarboxylic acid, biphenyldicarboxylic acid, naphthalenedicarboxylic acid, benzophenonedicarboxylic acid, francicarboxylic acid, 4,4'-dicarboxydiphenyl ether, 4,4'-dicarboxydiphenyl sulfide, etc. <Acid Chlorides> Acetyl chloride, acrylate chloride, methacrylate chloride, malonyl chloride, succinate dichloride, diglycolyl chloride, glutarate dichloride, suberate dichloride, sebacate dichloride, adipic acid dichloride, dodecane dioyl chloride, azera oil chloride, 2,5-franzicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesinate chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyl dicarbonyl chloride, 4,4'-azodibenzoyl dichloride, etc. <Lactams> ε-caprolactam, ω-undecane lactam, ω-laurolactam, etc.

[0056] Polyimide resin: Examples of polyimide resins include, but are not limited to, the reaction products of the above-mentioned diamine and the tetracarboxylic dianhydrides exemplified below. Furthermore, these may be used individually or in combination. <Tetracarboxylic dianhydrides> 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2-dicarboxylic anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4 '-diphenylsulfontetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, methylene-4,4'-diphthalic acid dianhydride, 1,1-ethylidene-4,4'-diphthalic acid dianhydride, 2,2'-propyridene-4,4'-diphthalic acid dianhydride, 1,2-ethylene-4,4'-diphthalic acid dianhydride, 1,3-trimethylene-4,4'-diphthalic acid dianhydride, 1,4-tetramethylene-4,4'-diphthalic acid dianhydride, 1,5-pentamethylene-4,4'- Diphthalic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride, thio-4,4'-diphthalic acid dianhydride, sulfonyl-4,4'-diphthalic acid dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4- [Dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-Dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 2,3,6,7-anthracenetetracarboxylic acid dianhydride, 1,2,7,8-phenanthrenetetracarboxylic acid dianhydride, ethylenetetracarboxylic acid dianhydride, 1,2,3,4-butanetetracarboxylic acid dianhydride, 1, 2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride (Bonic acid) dianhydride, 1,1-ethylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 2,2-propyridene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2,2,2]octo-7-ene-2,3,5,6-tetracarboxylic acid dianhydride Water compounds, rel-[1S,5R,6R]-3-oxabicyclo[3,2,1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, ethylene glycol-bis-(3,4-dicarboxylic acid anhydride phenyl) ether, 4,4'-biphenylbis(trimellitic acid monoester anhydride), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, etc.

[0057] Cyanate ester resins are cyanate ester compounds obtained by reacting phenol resins with cyanide halides. Specific examples include, but are not limited to, dicyanatebenzene, tricyanatebenzene, dicyanate naphthalene, dicyanate biphenyl, 2,2'-bis(4-cyanatephenyl)propane (BisA-OCN, manufactured by Mitsubishi Gas Chemical Company, Inc.), bis(4-cyanatephenyl)methane, bis(3,5-dimethyl-4-cyanatephenyl)methane, 2,2'-bis(3,5-dimethyl-4-cyanatephenyl)propane, 2,2'-bis(4-cyanatephenyl)ethane, 2,2'-bis(4-cyanatephenyl)hexafluoropropane, bis(4-cyanatephenyl)sulfone, bis(4-cyanatephenyl)thioether, phenol novolac cyanate, and phenol-dicyclopentadiene copolymers in which the hydroxyl groups have been converted to cyanate groups. Furthermore, the cyanate ester compounds whose synthesis method is described in Japanese Patent Publication No. 2005-264154 are particularly preferred as cyanate ester compounds because they have excellent low hygroscopicity, flame retardancy, and dielectric properties. The cyanate ester resin may contain catalysts such as zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octoate, tin octoate, lead acetylacetonate, dibutyltin maleate, or commercially available 18% octop Zn (manufactured by Hope Pharmaceutical Co., Ltd.) to trimerize the cyanate groups and form a sym-triazine ring as needed. The catalyst is usually used in an amount of 0.0001 to 0.10 parts by weight, preferably 0.00015 to 0.0015 parts by weight, per 100 parts by weight of the total weight of the curable resin composition.

[0058] Active ester resin: An active ester compound is a compound that contains at least one ester bond in its structure, and on both sides of the ester bond, an aliphatic chain, an aliphatic ring, or an aromatic ring is bonded. Examples of active ester compounds include compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. These are obtained by a condensation reaction between at least one compound of a carboxylic acid compound, an acid chloride, or a thiocarboxylic acid compound and at least one compound of a hydroxy compound or a thiol compound. In particular, from the viewpoint of improving heat resistance, it is preferable that the compound is obtained from a carboxylic acid compound or an acid chloride and a hydroxy compound, and phenol compounds or naphthol compounds are preferred as the hydroxy compound. Active ester compounds may be used alone or in combination of two or more.

[0059] Examples of the carboxylic acid compounds mentioned above include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

[0060] Examples of the above-mentioned acid chlorides include acetyl chloride, acrylate chloride, methacrylate chloride, malonyl chloride, succinate dichloride, diglycolyl chloride, glutarate dichloride, suberate dichloride, sebacate dichloride, adipic acid dichloride, dodecanediol dichloride, azera oil chloride, 2,5-franzicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, and 4,4'-azodibenzoyl dichloride.

[0061] Examples of the above-mentioned phenol compounds and 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, phenol novolac, and phenol resins described later. Here, "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by the condensation of two molecules of phenol with one molecule of dicyclopentadiene.

[0062] Preferred examples of active ester compounds include active ester compounds containing a dicyclopentadiene-type diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated phenol novolac, active ester compounds containing a benzoylated phenol novolac, the compound described in Example 2 of International Publication No. 2020 / 095829, and the compounds disclosed in International Publication No. 2020 / 059625. Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene-type diphenol structure are more preferred. The dicyclopentadiene-type diphenol structure represents a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

[0063] Commercially available active ester compounds include, for example, active ester compounds containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", "HPC-8000H-65TM", "EXB-8000L-65TM", and "EXB-8150-65T" (manufactured by DIC Corporation), and active ester compounds containing a naphthalene structure such as "EXB9416-70BK" (manufactured by DIC Corporation), and phenol no Examples of active ester compounds containing acetylated volac include "DC808" (manufactured by Mitsubishi Chemical Corporation), active ester compounds containing benzoylated phenol novolac include "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation), active ester curing agent which is an acetylated phenol novolac includes "DC808" (manufactured by Mitsubishi Chemical Corporation), and phosphorus atom-containing active ester curing agent includes "EXB-9050L-62M" manufactured by DIC Corporation.

[0064] Regarding the blending ratio of the active ester compound and epoxy resin, the ratio of the active ester equivalent (α) to the epoxy equivalent (β) (α / β) is preferably 0.5 to 1.5, more preferably 0.8 to 1.2, and even more preferably 0.90 to 1.10. If it falls outside the above range, there is a risk that excess epoxy groups or active ester groups will remain in the system, which may lead to deterioration of properties in high-temperature storage tests (e.g., 150°C, 1000 hours) or long-term reliability tests under high-temperature and high-humidity conditions (e.g., temperature: 85°C, humidity: 85%).

[0065] Curing accelerator: The curable resin composition of this embodiment can also have its curability improved by adding a curing accelerator. Preferred curing accelerators are anionic curing accelerators that promote the curing reaction by generating anions upon irradiation with ultraviolet light or visible light or by heating, or cationic curing accelerators that promote the curing reaction by generating cations upon irradiation with ultraviolet light or visible light or by heating.

[0066] Examples of anionic curing accelerators include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole; trialkylamines such as triethylamine and tributylamine; 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene, with 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene being preferred. Other examples include phosphines such as triphenylphosphine, tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, and quaternary ammonium salts such as hexadecyltrimethylammonium hydroxide, but are not limited to these. These may be used individually or in combination.

[0067] Examples of cationic curing accelerators include quaternary phosphonium salts such as triphenylbenzylphosphonium salt, triphenylethylphosphonium salt, and tetrabutylphosphonium salt (the counterions of the quaternary salts are halogens, organic acid ions, hydroxide ions, etc., with no particular preference, but organic acid ions and hydroxide ions are particularly preferred), tin octoate, zinc carboxylates (zinc 2-ethylhexanoate, zinc stearate, zinc behenate, zinc myristate), and zinc phosphate esters (zinc octyl phosphate, zinc stearyl phosphate), but are not limited to these. Furthermore, these may be used individually or in combination of multiple types.

[0068] The amount of curing accelerator used is 0.01 to 5.0 parts by mass per 100 parts by mass of the curable resin composition, as needed.

[0069] Polymerization initiator: The curable resin composition of this embodiment can also have its curability improved by adding a polymerization initiator. A polymerization initiator is a compound capable of polymerizing olefin functional groups such as ethylenically unsaturated bonds, and examples include olefin metathesis polymerization initiators, anionic polymerization initiators, cationic polymerization initiators, and radical polymerization initiators. Among these, it is preferable to use a radical polymerization initiator that has curability and appropriate stability. A radical polymerization initiator is a compound that generates radicals by irradiation with ultraviolet or visible light or by heating, and initiates a chain polymerization reaction. Suitable radical polymerization initiators include ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide, diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as dicumyl peroxide and 1,3-bis-(t-butylperoxyisopropyl)benzene, peroxyketals such as t-butyl peroxybenzoate and 1,1-di-t-butylperoxycyclohexane, α-cumyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, t-amyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, and t-amyl peroxy-3,5,5-trimethylhexanoate. Examples include, but are not limited to, alkyl peresters such as sanoates, t-butylperoxy-3,5,5-trimethylhexanoate, and t-amylperoxybenzoate; peroxycarbonates such as di-2-ethylhexyl peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, t-butylperoxyisopropyl carbonate, and 1,6-bis(t-butylperoxycarbonyloxy)hexane; organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide, t-butylperoxyoctoate, and lauroyl peroxide; azo compounds such as azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), and 2,2'-azobis(2,4-dimethylvaleronitrile); and benzopinacols.It is preferable to use organic peroxides because they allow for control of the curing temperature, suppression of outgassing, and have minimal impact on the electrical properties of decomposition products. The amount of radical polymerization initiator added is preferably 0.01 to 5 parts by weight, and particularly preferably 0.01 to 3 parts by weight, per 100 parts by weight of the curable resin composition. If the amount of radical polymerization initiator used is too large, the molecular weight will not elongate sufficiently during the polymerization reaction.

[0070] The curable resin composition of this embodiment may also contain a phosphorus-containing compound as a flame retardant component. The phosphorus-containing compound may be reactive or additive. Specific examples of phosphorus-containing compounds include phosphate esters such as trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixyllenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixyllenyl phosphate, 1,3-phenylenebis(dixyllenyl phosphate), 1,4-phenylenebis(dixyllenyl phosphate), and 4,4'-biphenyl(dixyllenyl phosphate); 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5- Phosphanes such as dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; phosphorus-containing epoxy compounds obtained by reacting epoxy resin with the active hydrogen of the phosphanes, red phosphorus, etc. are examples, but phosphate esters, phosphanes, or phosphorus-containing epoxy compounds are preferred, and 1,3-phenylenebis(dixyllenyl phosphate), 1,4-phenylenebis(dixyllenyl phosphate), 4,4'-biphenyl(dixyllenyl phosphate), or phosphorus-containing epoxy compounds are particularly preferred. The content of the phosphorus-containing compound is preferably in the range of (phosphorus-containing compound) / (total epoxy resin) of 0.1 to 0.6 (by weight). Below 0.1, the flame retardancy is insufficient, and above 0.6, there is a concern that it will adversely affect the hygroscopicity and dielectric properties of the cured product.

[0071] Furthermore, a light stabilizer may be added to the curable resin composition of this embodiment as needed. Suitable light stabilizers include hindered amine light stabilizers (HALS) and the like. While not specifically limited to HALS, representative examples include: dibutylamine-1,3,5-triazine-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine polycondensate, dimethyl-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine succinate polycondensate, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperi Examples include bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(1-octyroxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate bis(1,2,2,6,6-pentamethyl-4-piperidyl), etc. HALS may be used alone or in combination of two or more types.

[0072] Furthermore, a binder resin may be added to the curable resin composition of this embodiment as needed. Examples of binder resins include, but are not limited to, but but include butyral resins, acetal resins, acrylic resins, epoxy-nylon resins, NBR-phenol resins, epoxy-NBR resins, polyamide resins, polyimide resins, and silicone resins. The amount of binder resin added is preferably within a range that does not impair the flame retardancy and heat resistance of the cured product, preferably 0.05 to 50 parts by weight per 100 parts by weight of the resin component, and more preferably 0.05 to 20 parts by weight as needed.

[0073] Furthermore, the curable resin composition of this embodiment may optionally contain powders such as fused silica, crystalline silica, porous silica, alumina, zircon, calcium silicate, calcium carbonate, quartz powder, silicon carbide, silicon nitride, boron nitride, zirconia, aluminum nitride, graphite, forsterite, steatite, spinel, mullite, titania, talc, clay, iron oxide asbestos, and glass powder, or inorganic fillers made from these in spherical or crushed form. In particular, when obtaining a curable resin composition for semiconductor encapsulation, the amount of the above-mentioned inorganic filler used is usually in the range of 80 to 92% by weight, preferably 83 to 90% by weight, of the curable resin composition.

[0074] The curable resin composition of this embodiment may contain known additives as needed. Specific examples of additives that can be used include polybutadiene and its modified counterparts, modified acrylonitrile copolymers, polyphenylene ether, polystyrene and its modified counterparts, polyethylene and its modified counterparts, polyimide, fluororesin, silicone gel, silicone oil, surface treatment agents for fillers such as silane coupling agents, mold release agents, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green. The amount of these additives added is preferably 1,000 parts by weight or less, more preferably 700 parts by weight or less, per 100 parts by weight of the curable resin composition. From the viewpoint of low water absorption and electrical properties, polybutadiene and its modified counterparts, polyphenylene ether, polystyrene and its modified counterparts, polyethylene and its modified counterparts, and fluororesin are preferred. From the viewpoint of electrical properties, adhesion, and low water absorption, polystyrene and its modified counterparts, polyethylene and its modified counterparts, and polybutadiene and its modified counterparts are preferred. Specifically, for example, ethylene-propylene copolymer, ethylene-styrene copolymer, ethylene-propylene-ethylidene norbornene copolymer (Mitsui Chemicals EBT: K-8370EM, K-9330M, etc.), ethylene-propylene-vinyl norbornene copolymer (Mitsui Chemicals VNB-EPT: PX-006M, PX-008M, PX-009M, etc.), ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer (SBR: RICON-100, RICON-181, RICON-184) Examples include butadiene-based thermoplastic elastomers such as acrylonitrile butadiene copolymer (all manufactured by Clay Valley, etc.); styrene-based thermoplastic elastomers such as styrene-butadiene styrene copolymer (SBS), hydrogenated styrene-butadiene styrene copolymer, styrene-isoprene styrene copolymer (SIS), hydrogenated styrene-isoprene styrene copolymer, hydrogenated styrene (butadiene / isoprene) styrene copolymer, and styrene-ethylene propylene styrene copolymer. These styrene-based thermoplastic elastomers may be used individually or in combination of two or more types.Among these high molecular weight materials, styrene-based thermoplastic elastomers such as styrene-butadiene-styrene copolymer, hydrogenated styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, hydrogenated styrene-isoprene-styrene copolymer, and hydrogenated styrene(butadiene / isoprene)-styrene copolymer are preferred, and styrene-isoprene-styrene copolymer, hydrogenated styrene-butadiene-styrene copolymer, hydrogenated styrene-isoprene-styrene copolymer, hydrogenated styrene(butadiene / isoprene)-styrene copolymer, and styrene-ethylene-propylene-styrene copolymer are even more preferred because they have higher heat resistance and are less susceptible to oxidative degradation. Specifically, examples include Septon 1020, Septon 2002, Septon 2004F, Septon 2005, Septon 2006, Septon 2063, Septon 2104, Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099, Septon 8004, Septon 8006, Septon 8007L, Septon HG252, Septon V9827, Hybrar 7125 (hydrogenated), Hybrar 7215F, Hybrar 7311F, Septon 2104 (all manufactured by Kuraray Co., Ltd.). The weight-average molecular weight of the styrene-based thermoplastic elastomer is not particularly limited as long as it is 10,000 or more. However, if it is too high, the compatibility with polyphenylene ether compounds, as well as low molecular weight components with a weight-average molecular weight of about 50 to 1,000 and oligomer components with a weight-average molecular weight of about 1,000 to 5,000 deteriorates, making it difficult to ensure mixing and solvent stability. Therefore, it is preferable that the weight-average molecular weight is around 10,000 to 300,000. Generally, in the case of compounds containing heteroatoms such as oxygen and nitrogen, such as bismaleimide and polymaleimide, due to their polarity, it is difficult to ensure compatibility with low-polarity compounds such as compounds mainly composed of hydrocarbons or compounds composed only of hydrocarbons, among the above-mentioned additives and curable resin components. On the other hand, the maleimide resin mixture of this embodiment does not have a skeleton design that actively incorporates heteroatoms such as oxygen and nitrogen (it has few polar groups), and therefore exhibits excellent compatibility with materials that have low polarity and low dielectric properties, as well as compounds composed only of hydrocarbons.

[0075] The curable resin composition of this embodiment is obtained by uniformly mixing the above components in predetermined proportions. Pre-curing is typically performed at 130-180°C for 30-500 seconds, followed by post-curing at 150-250°C for 2-15 hours to ensure a sufficient curing reaction and obtain the cured product of this embodiment. Alternatively, the components of the curable resin composition can be uniformly dispersed or dissolved in a solvent, and then cured after removing the solvent.

[0076] The curable resin composition obtained in this embodiment has moisture resistance, heat resistance, and high adhesion. Therefore, the curable resin composition of this embodiment can be used in a wide range of fields where moisture resistance, heat resistance, and high adhesion are required. Specifically, it is useful as a material for all kinds of electrical and electronic components, such as insulating materials, laminates (printed wiring boards, BGA substrates, build-up substrates, etc.), encapsulating materials, and resists. In addition to molding materials and composite materials, it can also be used in fields such as paint materials, adhesives, and 3D printing. In particular, its solder reflow resistance is beneficial in semiconductor encapsulation.

[0077] The semiconductor device is sealed with the curable resin composition of this embodiment. Examples of semiconductor devices include DIP (Dual In-Line Package), QFP (Quad Flat Package), BGA (Ball Grid Array), CSP (Chip Size Package), SOP (Small Outline Package), TSOP (Thin Small Outline Package), TQFP (Thin Quad Flat Package), and the like.

[0078] The method for preparing the curable resin composition of this embodiment is not particularly limited, but may be done by simply uniformly mixing each component or by prepolymerization. For example, the maleimide resin mixture of this embodiment is prepolymerized by heating in the presence or absence of a catalyst, and in the presence or absence of a solvent. Similarly, in addition to the maleimide resin mixture of this embodiment, prepolymerization may be performed by adding curing agents such as epoxy resins, amine compounds, maleimide compounds, cyanate ester compounds, phenolic resins, and acid anhydride compounds, and other additives. Mixing or prepolymerizing each component can be done using, for example, an extruder, kneader, or roll in the absence of a solvent, and using a reaction vessel with a stirring device in the presence of a solvent.

[0079] A method for uniform mixing involves kneading the resin composition using equipment such as a kneader, roll, or planetary mixer at a temperature in the range of 50 to 100°C to obtain a uniform resin composition. The obtained resin composition can be pulverized and then molded into cylindrical tablets using a molding machine such as a tablet machine, or into granular powder or powdery molded bodies. Alternatively, these compositions can be melted on a surface support and molded into sheets with a thickness of 0.05 mm to 10 mm to obtain a curable resin composition molded body. The obtained molded body is non-sticky at 0 to 20°C and maintains its fluidity and curability with almost no decrease even after storage at -25 to 0°C for more than a week. The obtained molded body can be molded into a cured product using a transfer molding machine or a compression molding machine.

[0080] The curable resin composition of this embodiment can also be modified by adding an organic solvent to obtain a varnish-like composition (hereinafter simply referred to as varnish). The curable resin composition of this embodiment can be dissolved in a solvent such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, or N-methylpyrrolidone as needed to form a varnish. This varnish can then be impregnated into a substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, or paper, and the resulting prepreg can be heat-dried. The prepreg obtained can then be hot-press-molded to produce a cured product of the curable resin composition of this embodiment. In this case, the solvent used is typically in an amount that accounts for 10 to 70% by weight, preferably 15 to 70% by weight, of the mixture of the curable resin composition of this embodiment and the solvent. If the composition is in liquid form, a cured product of the curable resin containing carbon fibers can also be obtained directly, for example, by the RTM (Resin Transfer Molding) method.

[0081] Furthermore, the curable composition of this embodiment can also be used as a modifier for film-type compositions. Specifically, it can be used to improve flexibility and other properties in the B-stage. Such a film-type resin composition can be obtained as a sheet-like adhesive by applying the curable resin composition of this embodiment as a curable resin composition varnish onto a release film, removing the solvent under heating, and then performing B-stage formation. This sheet-like adhesive can be used as an interlayer insulating layer in multilayer substrates and the like.

[0082] The curable resin composition of this embodiment can be heated and melted to reduce viscosity and impregnate reinforcing fibers such as glass fibers, carbon fibers, polyester fibers, polyamide fibers, and alumina fibers to obtain a prepreg. Specific examples include, but are not limited to, glass fibers such as E glass cloth, D glass cloth, S glass cloth, Q glass cloth, spherical glass cloth, NE glass cloth, and T glass cloth; inorganic fibers other than glass; poly(p-phenylene terephthalamide) (Kevlar®, manufactured by DuPont); fully aromatic polyamides; polyesters; and organic fibers such as poly(p-phenylene benzoxazole), polyimide, and carbon fibers. The shape of the substrate is not particularly limited, but examples include woven fabrics, nonwoven fabrics, rovings, and chopped strand mats. As for the weaving method of the woven fabric, plain weave, twill weave, etc., are known, and these can be appropriately selected and used depending on the intended application and performance. Furthermore, glass woven fabrics that have been opened or surface-treated with a silane coupling agent are preferably used. The thickness of the base material is not particularly limited, but is preferably about 0.01 to 0.4 mm. Alternatively, a prepreg can be obtained by impregnating the reinforcing fibers with the varnish and then heating and drying them.

[0083] The laminate of this embodiment comprises one or more of the above-mentioned prepregs. The laminate is not particularly limited as long as it comprises one or more of the above-mentioned prepregs, and may have any other layers. The method for manufacturing the laminate is not particularly limited and can be any generally known method that can be applied as appropriate. For example, when forming a metal foil laminate, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, an autoclave molding machine, etc., can be used, and the above-mentioned prepregs can be laminated together and a laminate can be obtained by heating and pressing. At this time, the heating temperature is not particularly limited, but 65 to 300°C is preferred, and 120 to 270°C is more preferred. The pressurizing pressure is not particularly limited, but if the pressurizing pressure is too high it is difficult to adjust the solid content of the resin in the laminate and the quality will not be stable, and if the pressurizing pressure is too low it will result in air bubbles and poor adhesion between the layers, so 2.0 to 5.0 MPa is preferred, and 2.5 to 4.0 MPa is more preferred. The laminate of this embodiment can be suitably used as a metal foil laminate described later by comprising a layer made of metal foil. By cutting the above prepreg into the desired shape, laminating it with copper foil or other materials as needed, and then applying pressure to the laminate using methods such as press molding, autoclave molding, or sheet winding molding while heating and curing a curable resin composition, electrical and electronic laminates (printed wiring boards) and carbon fiber reinforced materials can be obtained.

[0084] The cured product of this embodiment can be used in various applications such as molding materials, adhesives, composite materials, and paints. Because the cured product of the curable resin composition described in this embodiment exhibits excellent heat resistance and dielectric properties, it is suitably used in electrical and electronic components such as encapsulants for semiconductor devices, encapsulants for liquid crystal display devices, encapsulants for organic EL devices, printed circuit boards, and build-up laminates, as well as in composite materials for lightweight, high-strength structural materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics.

[0085] The cured product of this embodiment preferably has a dielectric loss tangent of less than 0.0016 at a frequency of 10 GHz measured at 25°C, and more preferably less than 0.0013.

[0086] (Another Embodiment) The cured product of this embodiment can further be used as a resist film, an interlayer insulating material for build-up methods, or an optical waveguide on substrates such as printed circuit boards, optoelectronic substrates, and optical substrates. Specific examples of these applications include, for example, computers, home appliances, and portable devices. The thickness of this cured product layer is typically about 0.5 to 160 μm, and preferably about 1 to 100 μm.

[0087] The curable resin composition of this embodiment preferably contains a photopolymerization initiator. A photoradical polymerization initiator or a photocationic polymerization initiator is preferred as the photopolymerization initiator. The content of the photopolymerization initiator is 0.001 to 20 parts by mass, more preferably 0.002 to 15 parts by mass, per 100 parts by mass of the resin component. A content of less than 0.001 parts by mass may result in insufficient photocuring, while a content of more than 20 parts by mass may worsen the dielectric properties. Preferred photopolymerization initiators are exemplified below, but the invention is not limited to these; they may be used individually or in combination of two or more.

[0088] Photoradical polymerization initiators: While not particularly limited, any compound that generates radicals and initiates a chain polymerization reaction upon irradiation with ultraviolet or visible light can be used as a photoradical polymerization initiator. Examples include benzyldimethyl ketal, 1-hydroxycyclohexylphenyl ketone, diethylthioxanthone, benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propane, 2,4,6-trimethylbenzoyldiphenylphosphate, camphorquinone, 9-fluorenone, and diphenyl disulfide. Specifically, IRGACURE... ＲＴＭ 651, 184, 2959, 127, 907, 369, 379EG, 819, 784, 754, 500, OXE01, OXE02, OXE03, OXE04, DAROCURE ＲＴＭ 1173, LUCIRIN ＲＴＭ TPO (both manufactured by BASF), Sequall ＲＴＭExamples include Z, BZ, BEE, BIP, BBI (all manufactured by Seiko Chemical Co., Ltd.), Kayacure DETX-S (manufactured by Nippon Kayaku Co., Ltd.), etc. Among these, the oxime ester initiators IRGACURER OXE01, OXE02, OXE03, and OXE04 are preferred.

[0089] Photocationic polymerization initiators: Photocationic polymerization initiators are not particularly limited to radical polymerization initiators, as long as they are compounds that generate cation species such as Brønsted acids and Lewis acids upon irradiation with ultraviolet or visible light, but aromatic iodonium complex salts and aromatic sulfonium complex salts can be given as examples. Specific examples of aromatic iodonium complex salts include diphenyliodonium tetrakis(pentafluorophenyl) borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, di(4-nonylphenyl)iodonium hexafluorophosphate, tolylcmyliodonium tetrakis(pentafluorophenyl) borate (manufactured by Rhodey, trade name: Rhodey PI2074), and di(4-tert-butyl)iodonium tris(trifluoromethanesulfonyl) methanide (manufactured by BASF, trade name: CGIBBI-C1). Specific examples of aromatic sulfonium complex salts include 4-thiophenyldiphenylsulfonium hexafluoroantimonate (manufactured by Sunapro, trade name: CPI-101A), thiophenyldiphenylsulfonium tris(pentafluoroethyl)trifluorophosphate (manufactured by Sunapro, trade name: CPI-210S), 4-{4-(2-chlorobenzoyl)phenylthio}phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate (manufactured by ADEKA, trade name: SP-172), and aromatic sulfonium hexafluoroantimonate containing 4-thiophenyldiphenylsulfonium hexafluoroantimonate. Examples include a mixture of thymonates (manufactured by ACETOCorporate USA, trade name: CPI-6976), triphenylsulfonium tris(trifluoromethanesulfonyl)methandide (manufactured by BASF, trade name: CGITPS-C1), tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tris(trifluoromethylsulfonyl)methide (manufactured by BASF, trade name: GSID26-1), and tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl)borate (manufactured by BASF, trade name: Irgacure PAG290).Of these, in the present invention, aromatic sulfonium complex salts that have high vertical rectangular processability and high thermal stability are preferred in the photosensitive image forming process. Among these, a mixture of aromatic sulfonium hexafluoroantimonates containing 4-{4-(2-chlorobenzoyl)phenylthio}phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate and 4-thiophenyldiphenylsulfonium hexafluoroantimonate, and tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl)borate are particularly preferred.

[0090] The curable resin composition of this embodiment can be used by known methods. For example, the curable resin composition of the present invention, whose viscosity has been adjusted with an organic solvent, can be applied to a support and then dried at 50 to 180°C, preferably 80 to 140°C, for 5 to 30 minutes to obtain a film-like curable resin composition. Examples of the support include silicon wafers, ceramic substrates, rigid substrates, flexible substrates, and silicon wafers on which an inorganic surface protective film such as a SiN film or SiO2 film has been formed.

[0091] The coating method is not particularly limited, but examples include coating using a spin coater, slit coater, roll coater, etc., and screen printing. Among these, for example, when coating a silicon wafer, it is preferable to use a coating method using a spin coater. The film thickness of the film-like curable resin composition can be arbitrarily adjusted by adjusting the concentration of the curable resin composition and the coating thickness, and is not particularly limited, but for example, when it is used as a protective film for semiconductor devices or an interlayer insulating film, the film thickness after drying is preferably 3 to 50 μm, more preferably 5 to 30 μm, and even more preferably 5 to 20 μm. If the film thickness is less than 3 μm, it tends not to adequately protect the devices and circuits beneath the film, and if it exceeds 50 μm, it tends not to be possible to form fine patterns. In the present invention, even with a film thickness of 10 μm or more (preferably 10 to 20 μm), it is possible to form fine patterns, and it is possible to form patterns in which the aspect ratio of the aperture diameter (via diameter) of the through holes formed by exposure and development described later is 0.3 or more (more preferably 0.5 or more).

[0092] Next, the film-like curable resin composition obtained in this manner is exposed to light by applying a mask having a predetermined pattern shape to it, thereby photopolymerizing the curable resin composition of the present invention. The exposure method can be contact exposure or reduction projection exposure. The exposure wavelength is preferably ultraviolet to visible light in the range of 200 to 500 nm, and a standard reduction projection exposure machine (stepper) can be used. Furthermore, from the viewpoint of forming fine patterns, the exposure wavelength is more preferably 256 to 436 nm, and even more preferably 256 to 365 nm. The exposure amount is not particularly limited, but is preferably 100 to 5000 mJ / cm². ２ Preferably, the concentration is 300 to 3000 mJ / cm². ２ It is preferable that it be so.

[0093] Next, by developing the film-like curable resin composition after exposure, dissolving and removing the unexposed portion with a developer, a polymerized film (polymer) having a predetermined pattern can be obtained. That is, in the exposed portion, radicals or cation species generated from the photopolymerization initiator by light irradiation cause crosslinking between component (A) and other compounds, making them insoluble in the developer. In contrast, the unexposed portion dissolves in the developer, so by utilizing the difference in solubility between the exposed and unexposed portions in the developer, a polymerized film having a pattern such as through-holes of a predetermined aperture diameter (Via diameter) can be obtained. As the developer, the aforementioned solvent can be used, and it may further contain alcohol-based solvents such as methanol, ethanol, or propanol to adjust the solubility during development. Examples of the development method include the spray method, the paddle method, and the dip method.

[0094] Furthermore, it is preferable to further rinse the polymerized film having a predetermined pattern obtained by the development with an organic solvent such as cyclopentanone or a mixed solvent of cyclopentanone and ethanol. The polymerized film after development preferably has a residual film rate of 90% or more, from the viewpoint of suppressing surface roughness and facilitating dimensional design. In the present invention, the residual film rate refers to the ratio of the thickness of the polymerized film after development to the thickness of the film-like curable resin composition after drying (before exposure) (thickness of the polymerized film after development / thickness of the film-like curable resin composition after drying (before exposure)).

[0095] Next, the polymerized film having a predetermined pattern obtained by the development process can be heated and cured as needed to obtain a cured film (cured product) having a predetermined pattern. The heating temperature (curing temperature) is preferably 60 to 230°C, and more preferably 150 to 230°C. The heating time is preferably 30 to 120 minutes. In this invention, the curing temperature refers to the temperature required to thermally cure the functional groups that remain unreacted during exposure through a thermal reaction.

[0096] As described above, by using the curable resin composition of the present invention, a cured film having a fine pattern can be obtained. Preferably, the aspect ratio of the aperture diameter (via diameter) of the formed through-holes is 0.3 or greater, and more preferably 0.5 or greater. In this invention, the aperture diameter can be determined by measuring it using an optical microscope or a scanning electron microscope (SEM).

[0097] The cured product obtained using such a curable resin composition of the present invention after photocuring or photothermal curing (curing by combining photocuring and thermal curing) can be suitably used for at least one type of film selected from the group consisting of surface protective films for semiconductor devices, interlayer insulating films, and insulating films for redistribution layers. Furthermore, the curable resin composition of the present invention is particularly effective when such a film requires a film thickness of 10 μm or more, and when patterning is required such that the aspect ratio of the through-hole opening diameter (via diameter) is 0.3 or more (more preferably 0.5 or more).

[0098] Next, the present invention will be described in more detail with reference to examples. Hereinafter, unless otherwise specified, parts refer to parts by weight. However, the present invention is not limited to these examples.

[0099] The various analytical methods used in the examples are described below. <Gel Permeation Chromatography (GPC)> Manufacturer: Waters Column: Guard Column SHODEX GPC KF-601 (2), KF-602, KF-602.5, KF-603 Flow rate: 1.23 ml / min. Column temperature: 25℃ Solvent used: THF (tetrahydrofuran) Detector: RI (differential refractive detector)

[0100] <Acid Value Measurement> Apparatus: Hiranuma Automatic Titrator COM-1600 Apparatus Conditions: Reference electrode RE-201, Platinum indicator electrode PT-301 Measurement Method: The acid value was measured in accordance with JIS K 2501 "Petroleum Products and Lubricating Oils - Neutralization Value Test Method". The titration solvent was a THF / IPA mixed solvent (v / v = 7 / 3). 50 ml of the titration solvent was measured into a beaker, and 5 ml of buffer storage solution B for petroleum product neutralization value measurement was added to the sample. The pH was measured and the endpoint pH was determined. Then, 50 ml of the titration solvent was measured into a beaker and titrated with 0.1 mol / L 2-propanolic potassium hydroxide solution (for petroleum product neutralization value measurement) using a potentiometric titrator to obtain a blank value. 0.4 g of the maleimide resin mixture obtained in Examples and Comparative Examples was accurately weighed into a beaker, 50 ml of titration solvent was added and dissolved with a stirrer, and the solution was titrated to the endpoint.

[0101] [Example 1] A flask equipped with a thermometer, condenser, Dean-Stark azeotropic distillation trap, and stirrer was charged with 16.5 parts toluene, 5.5 parts n-methylpyrrolidone, 10.6 parts 4,4-methylenebis(2-ethyl-6-methylaniline), 0.4 parts methanesulfonic acid, and 22.4 parts styrene-maleic anhydride copolymer (acid value: 151, Mn: 2,454, Mw: 4,997), and reacted at 120°C for 15 hours. After cooling, 8.3 parts toluene, 2.8 parts n-methylpyrrolidone, and 6.6 parts maleic anhydride were added, and the reaction was continued under reflux for 6 hours. After cooling, the reaction solution was diluted with 202.6 parts of toluene, and the organic layer was washed with 76.5 parts of 10% saline solution until the waste liquid was neutral. The organic layer was then washed once with 76.5 parts of 20% 1-propanol aqueous solution and twice with 76.5 parts of 6% 1-propanol aqueous solution. The target compound (M1) was then obtained as toluene varnish by distilling off the solvent from the organic layer under reduced pressure. The GPC chart of the obtained compound is shown in Figure 1. The proportion of component (c), determined from the area ratio of the peaks in the maleimide resin mixture in the GPC, was 37.7%. The acid value was 6.6. From the acid value and molecular weight of the raw material styrene-maleic anhydride copolymer, m was calculated to be 41.6 and n to be 6.7.

[0102] [Example 2] A flask equipped with a thermometer, condenser, Dean-Stark azeotropic distillation trap, and stirrer was charged with 191.8 parts toluene, 63.9 parts n-methylpyrrolidone, 123.6 parts 4,4-methylenebis(2-ethyl-6-methylaniline), 4.9 parts methanesulfonic acid, and 260.1 parts styrene-maleic anhydride copolymer (acid value: 151, Mn: 2,454, Mw: 4,997), and reacted at 120°C for 15 hours. After cooling, 95.9 parts toluene, 32.0 parts n-methylpyrrolidone, and 103.0 parts maleic anhydride were added, and the reaction was continued under reflux for 6 hours. After cooling, the reaction solution was diluted with 4610.6 parts toluene, the organic layer was washed with 1,740 parts 10% saline solution until the waste liquid was neutral, and then the organic layer was washed three times with 1,740 parts 16.0% isopropanol aqueous solution. The target compound (M2) was obtained as toluene varnish by distilling off the solvent under heating and reduced pressure. The GPC chart of the obtained compound is shown in Figure 2. The proportion of component (c), determined from the area ratio of the peaks in the maleimide resin mixture in the GPC, was 18.1%. The acid value was 4.3. From the acid value and molecular weight of the raw material styrene-maleic anhydride copolymer, m was calculated to be 41.6 and n to be 6.7.

[0103] [Comparative Example 1] A flask equipped with a thermometer, condenser, Dean-Stark azeotropic distillation trap, and stirrer was charged with 75.0 parts toluene, 25.0 parts n-methylpyrrolidone, 5.6 parts 4,4-methylenebis(2-ethyl-6-methylaniline), 0.3 parts methanesulfonic acid, and 13.2 parts styrene-maleic anhydride copolymer (acid value: 85, Mn: 1,979, Mw: 3,088), and reacted at 120°C for 3 hours. After cooling, 3.9 parts maleic anhydride was added, and the reaction was continued under reflux for 8 hours. After cooling, the reaction solution was diluted with 100.0 parts toluene, and the organic layer was washed with 100.0 parts warm water until the waste liquid was neutral. The target compound (M3) was obtained as a brown solid resin by distilling off the solvent under heating and reduced pressure. The GPC chart of the obtained compound is shown in Figure 3. The proportion of component (c), determined from the area ratio of GPC peaks, was 34.4%. The acid value was 28.7. From the acid value and molecular weight of the raw material, styrene-maleic anhydride copolymer, m was calculated to be 27.4 and n to be 2.3.

[0104] [Comparative Example 2] A flask equipped with a thermometer, condenser, Dean-Stark azeotropic distillation trap, and stirrer was charged with 60 parts toluene, 20.0 parts n-methylpyrrolidone, 8.5 parts 4,4-methylenebis(2-ethyl-6-methylaniline), 0.2 parts methanesulfonic acid, and 12.0 parts styrene-maleic anhydride copolymer (acid value: 240, Mn: 1,978, Mw: 3,107), and reacted at 120°C for 3 hours. After cooling, 3.9 parts maleic anhydride was added, and the reaction was continued under reflux for 8 hours. After cooling, the reaction solution was diluted with 100.0 parts toluene, and the organic layer was washed with 100.0 parts warm water until the waste liquid was neutral. The target compound (M4) was obtained as a brown solid resin by distilling off the solvent under heating and reduced pressure. The GPC chart of the obtained compound is shown in Figure 4. The proportion of component (c), determined from the area ratio of GPC peaks, was 37.1%. The acid value was 38.5. From the acid value and molecular weight of the raw material, styrene-maleic anhydride copolymer, m was calculated to be 26.2 and n to be 3.9.

[0105] <Solvent Solubility and Storage Stability Test> The maleimide resins obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were diluted with toluene to a resin content of 60% by weight. 1 g of the toluene-diluted maleimide resin mixture was placed in a 6 cc screw-top bottle, sealed with the lid, and left to stand in a refrigerator at 5.0–10.0°C for 24 hours. The presence or absence of crystal precipitation was then visually checked. ○ indicates no crystal precipitation, and × indicates precipitation, and the results are shown in Table 1.

[0106]

[0107] The results in Table 1 confirm that the maleimide resins obtained in Examples 1 and 2 exhibit excellent solvent solubility and storage stability in solution (varnish).

[0108] [Examples 3-6] A 250 μm cushion paper with a 100 mm x 50 mm cutout in the center was placed on a copper foil. 5.0 g of the sample, formulated according to the ratios shown in Table 2, was placed in the center of the frame, and with copper foil sandwiched on either side, the mixture was molded using a vacuum heating press and cured at 220°C for 2 hours. Subsequently, a cured film was obtained by etching the copper foil with ferric chloride. The dielectric loss tangent and glass transition temperature (Tg) of the cured film, measured by the method described below, are shown in Table 2.

[0109] <Dielectric Loss Tangent Test> A 10GHz cavity resonator manufactured by AET Co., Ltd. was used to perform the test at 25°C using the cavity resonator perturbation method. The sample size was 1.7 mm wide x 100 mm long, with a thickness of 1.7 mm. <Heat Resistance Test (DMA)> Apparatus: DMA Q800 (TA instruments) Measurement temperature range: 30 to 350°C Heating rate: 2°C / min Sample size: 5 mm wide x 40 mm long x 0.5 mm thick Judgment criterion: The peak point of tanδ is defined as Tg.

[0110]

[0111] - Asenaphthylene: Manufactured by JFE Chemical Co., Ltd., S1 (The solvent of the styrene resin obtained by the method described in Example 1 of Japanese Patent Publication No. 7353538 is removed by heating and reducing pressure) - 2E4MZ: 2-ethyl-4-methylimidazole (curing accelerator, manufactured by Shikoku Chemicals Co., Ltd.)

[0112] The results in Table 2 confirm that Examples 3 to 6 possess excellent low dielectric loss tangent. The attenuation rate of signals flowing through the dielectric material constituting a printed circuit board is proportional to the dielectric loss tangent. Since signal attenuation directly translates into heat generation and causes a temperature rise, a low dielectric loss tangent is important for printed circuit board materials and the like.

[0113] <Curing Test> [Reference Example 1] 5 parts of the compound (M1) obtained in Example 1, 20 parts of NC-3000 (manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin), MDEA: 4,0.5 parts of 4'-methylenebis(2-ethyl-6-methylaniline) (manufactured by Tokyo Chemical Industry Co., Ltd., amine compound), 1 part of DICY: dicyandiamide (manufactured by Tokyo Chemical Industry Co., Ltd., amide compound), 0.5 parts of KAYAHARD MCD (manufactured by Nippon Kayaku Co., Ltd., acid anhydride compound), KAYAHARD 0.5 parts of GPH-65 (manufactured by Nippon Kayaku Co., Ltd., biphenylaralkyl type phenol resin), 0.5 parts of Unifiner W-575 (manufactured by Unitika Corporation, activated ester resin), 0.5 parts of G4-142MHR (manufactured by Nippon Kayaku Co., Ltd., carboxylic acid compound), 2.5 parts of MIR-3000-70MT (manufactured by Nippon Kayaku Co., Ltd., maleimide compound), 2.5 parts of MIZ-001 (manufactured by Nippon Kayaku Co., Ltd., maleimide compound), 0.5 parts of Phenylmaleimide (manufactured by Tokyo Chemical Industry Co., Ltd., maleimide compound), 0.5 parts of SYTESTER TA (manufactured by Mitsubishi Gas Chemical Company, bisphenol A type cyanate resin), OPE-2st 60 parts of 2200 (a polyphenylene ether compound manufactured by Mitsubishi Gas Chemical Co., Ltd.), 3 parts of the compound described in Example 10 of Japanese Patent No. 6951829 (a compound having an ethylenically unsaturated bond), and KAYARAD 1 part R-684 (manufactured by Nippon Kayaku Co., Ltd., compound having an ethylenically unsaturated bond), 0.5 parts acenaphthylene (manufactured by Tokyo Chemical Industry Co., Ltd., compound having an ethylenically unsaturated bond), 1 part polyimide compound obtained by the method described in WO2023 / 013224A1, 1 part TAIC: triallyl isocyanurate (manufactured by Mitsubishi Chemical Corporation, allyl compound), 1 part Septon 2104 (manufactured by Kuraray Co., Ltd., modified polystyrene), 1 part P-d type benzoxazine (manufactured by Shikoku Chemicals Co., Ltd., benzoxazine compound), 0.5 parts 2E4MZ: 2-ethyl-4-methylimidazole (manufactured by Shikoku Chemicals Co., Ltd., curing accelerator), 0.5 parts TPP: triphenylphosphine (manufactured by Hokko Chemical Co., Ltd., curing accelerator), 0.1 parts Octop Zn (manufactured by Hope Pharmaceutical Co., Ltd., curing accelerator), Sun-Aid A cured product was obtained by mixing 0.1 parts of SI-B5 (manufactured by Sanshin Chemical Co., Ltd., curing accelerator), 1 part of DCP: dicumyl peroxide (manufactured by Kayaku Nurion Co., Ltd., polymerization initiator), 99.2 parts of toluene as a solvent, and 49.6 parts of tetrahydrofuran, and heating under a nitrogen atmosphere at 110°C for 10 minutes and then at 220°C for 1 hour.

[0114] [Reference Example 2] 5 parts of the compound obtained in Example 1 (M1), 50 parts of NC-3000 (manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin), 10 parts of MIZ-001 (manufactured by Nippon Kayaku Co., Ltd., maleimide compound), 5 parts of the compound described in Example 10 of Japanese Patent No. 6951829 (manufactured by Nippon Kayaku Co., Ltd., compound having an ethylenically unsaturated bond), 45 parts of KAYARAD R-684 (manufactured by Nippon Kayaku Co., Ltd., compound having an ethylenically unsaturated bond), 1 part of Irgacure OXE-04 (manufactured by BASF, polymerization initiator), Irgacure BASF 290 (polymerization initiator) was added in a 1:1 ratio and coated onto a PET film to a thickness of 100 μm. Another PET film was then attached to the side not in contact with the film, and the mixture was heated under a high-pressure mercury lamp (365 nm) at a concentration of 3000 mJ / cm². ２ By irradiating it with ultraviolet light, a cured product could be obtained.

[0115] The curable resin composition and its cured product of the present invention are useful for insulating materials for electrical and electronic components (such as high-reliability semiconductor encapsulating materials) and laminates (such as printed circuit boards, BGA substrates, and build-up substrates), adhesives (such as conductive adhesives), various composite materials including CFRP, paints, 3D printing, and other applications.

[0116] [Note] As described above, this embodiment includes the following disclosures: [1] A maleimide resin mixture comprising a maleimide resin having repeating units of the following formulas (a) and (b), and a maleimide resin represented by the following formula (c), wherein the acid value is 15 or less.

[0117]

[0118] (In the above formula, Ra represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms. m is the average number of repeats, where 1 ≤ m < 200. n is the average number of repeats, where 1.1 ≤ n < 100. (a) and (b) are bonded by *, and the repeat positions may be random.)

[0119]

[0120] [2] The maleimide resin mixture according to item [1] above, wherein the content of the maleimide resin represented by formula (c) in the total amount of the maleimide resin mixture is 5.0 area% or more and 50.0 area% or less in terms of GPC area percentage. [3] The maleimide resin mixture according to item [1] above, wherein the content of the maleimide resin represented by formula (c) in the total amount of the maleimide resin mixture is more than 30.0 area% and 50.0 area% or less in terms of GPC area percentage. [4] A curable resin composition containing the maleimide resin mixture according to any one of items [1] to [3] above. [5] The curable resin composition according to item [4], further comprising at least one selected from the group consisting of maleimide resins other than the maleimide resin mixture, polyphenylene ether compounds, compounds having ethylenically unsaturated bonds, cyanate ester resins, polybutadiene and modified thereof, polystyrene and modified thereof, polyethylene and modified thereof, benzoxazine compounds, epoxy resins, active ester compounds, phenol resins, amine resins, isocyanate resins, polyamide resins, and polyimide resins. [6] The curable resin composition according to item [4] or [5], further comprising a curing accelerator. [7] The curable resin composition according to any one of items [4] to [6], for use on printed circuit boards. [8] A varnish comprising the maleimide resin mixture according to any one of items [1] to [3] and an organic solvent. [9] A varnish comprising the curable resin composition according to any one of items [4] to [7] and an organic solvent.

[10] A cured product obtained by curing the maleimide resin mixture described in any one of the preceding paragraphs [1] to [3].

[11] A cured product obtained by curing the curable resin composition described in any one of the preceding paragraphs [4] to [7].

[12] A cured product according to paragraph

[10] or

[11] , wherein the dielectric loss tangent at a frequency of 10 GHz measured at 25°C is less than 0.0016.

Claims

1. A maleimide resin mixture comprising a maleimide resin having repeating units of the following formulas (a) and (b), and a maleimide resin represented by the following formula (c), wherein the acid value is 15 or less. (In the above formula, Ra represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms. m is the average number of repeats, where 1 ≤ m < 200. n is the average number of repeats, where 1.1 ≤ n < 100. (a) and (b) are bonded by *, and the repeat positions may be random.) 2. The maleimide resin mixture according to claim 1, wherein the content of the maleimide resin represented by formula (c) in the total amount of the maleimide resin mixture is 5.0 area% or more and 50.0 area% or less in terms of GPC area percentage.

3. The maleimide resin mixture according to claim 1, wherein the content of the maleimide resin represented by formula (c) in the total amount of the maleimide resin mixture is more than 30.0 area% and 50.0 area% or less in terms of GPC area percentage.

4. A curable resin composition containing the maleimide resin mixture according to any one of claims 1 to 3.

5. The curable resin composition according to claim 4, further comprising at least one selected from the group consisting of maleimide resins other than the maleimide resin mixture, polyphenylene ether compounds, compounds having ethylenically unsaturated bonds, cyanate ester resins, polybutadiene and modified thereof, polystyrene and modified thereof, polyethylene and modified thereof, polymerization initiators, epoxy resins, active ester compounds, phenolic resins, amine resins, isocyanate resins, polyamide resins, polyimide resins, and benzoxazine compounds.

6. The curable resin composition according to claim 4, further comprising a curing accelerator.

7. The curable resin composition according to claim 4, for use in printed circuit boards.

8. A varnish comprising the maleimide resin mixture and an organic solvent according to any one of claims 1 to 3.

9. A varnish comprising the curable resin composition and an organic solvent as described in claim 4.

10. A cured product obtained by curing the maleimide resin mixture according to any one of claims 1 to 3.

11. A cured product obtained by curing the curable resin composition described in claim 4.

12. The cured product according to claim 11, wherein the dielectric loss tangent at a frequency of 10 GHz measured at 25°C is less than 0.0016.

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