Curable resin composition, varnish and cured product thereof

Abstract

The present invention provides a curable resin composition excellent in low dielectric tangent and a cured product thereof. A maleimide resin mixture comprising a maleimide resin having repeating units of the following formulas (a) and (b) and bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by the following formula (c), and a photo radical polymerization initiator, wherein the content of the maleimide resin represented by the formula (c) in the total amount of the maleimide resin mixture is 5.0 to 30.0 area% in terms of GPC area percentage. 【Chemical 1】 TIFF0007744551000010.tif74165(In the above formula (a), m is the average value of the number of repetitions, and 0 < m < 200. In the above formula (b), n is the average value of the number of repetitions, and 0 < n < 100. (a) and (b) are each bonded by *, and the repeating positions may be random.) 【Chemical 2】 TIFF0007744551000011.tif67165

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition, a varnish, and a cured product thereof, which are suitable for use in semiconductor encapsulants, printed wiring boards, build-up laminates, resist films, electric and electronic components such as optoelectronic boards and optical boards, lightweight, high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, and 3D printing applications. [Background technology]

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

[0003] The fifth generation communication system "5G", whose development is currently accelerating, is expected to further increase capacity and speed of communication. 5G will use higher frequencies, but reducing transmission loss is important to achieve high-speed communication using high frequencies, and even lower dielectric properties will be required for circuit board materials. Transmission loss that occurs on printed circuit boards comes from conductor loss and dielectric loss. As stated in Non-Patent Document 1, dielectric loss α D is the relative permittivity of the dielectric, ε r and the dielectric loss tangent tanδ, the relative dielectric constant ε r It can be said that improving the dielectric loss tangent tanδ, which has a large contribution to the above, is effective. Thermoplastic materials such as PTFE (polytetrafluoroethylene) and LCP (liquid crystal polymer) are examples of materials with low dielectric loss tangent, but they are less moldable than thermosetting resins. In light of this, there is a need to develop thermosetting resins with excellent low dielectric properties.

[0004] Furthermore, in order to meet the demands for smaller, thinner, and higher density semiconductor packages (hereinafter referred to as PKG) used in smartphones and other devices, thinner PKG substrates are being sought, but as the PKG substrate becomes thinner, its rigidity decreases, which can lead to defects such as large warping caused by the heat generated when soldering the PKG to the motherboard (PCB).To alleviate this, there is a demand for PKG substrate materials with a high Tg (260°C) that is higher than the soldering temperature.

[0005] In light of this situation, maleimide resins have been investigated in recent years as a material for printed wiring boards in the high-frequency region. Maleimide resins themselves are characterized by high heat resistance due to their high crosslink density, but as pointed out in Patent Document 1 below, bismaleimide compounds having an imide structure in the molecule are highly crystalline and have a high melting point of about 150°C, close to the 170-180°C benchmark for the initiation of self-reaction. Therefore, they are difficult materials to prepare an impregnation varnish, impregnate with it, and dry, or to melt-mix with epoxy resins, curing agents, fillers, etc. to produce molding materials. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] "Signal Loss Factors in High-Speed ​​Signal Transmission on Printed Circuit Boards," 29th Spring Conference of the Japan Institute of Electronics Packaging, Session ID: 16P1-17, 2015 [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2018-12671 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of such a situation, and an object thereof is to provide a curable resin composition having excellent low dielectric tangent and a cured product thereof.

Means for Solving the Problems

[0009] That is, the present invention relates to the following [1] to

[10] . In the present application, “(numerical value 1) to (numerical value 2)” indicates that the upper and lower limit values are included. [1] A curable resin composition containing a maleimide resin having repeating units of the following formulas (a) and (b) and a maleimide resin mixture composed of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by the following formula (c), In the total amount of the maleimide resin mixture, the content of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by the formula (c) is 5.0 to 30.0 area% in terms of GPC area percentage.

[0010]

Chemical formula

[0011] In the above formula (1), m is the average value of the number of repetitions, and 0 < m < 200. In the above formula (b), n is the average value of the number of repetitions, and 0 < n < 100. (a) and (b) are each bonded with *, and the repeating positions may be random.

[0012]

Chemical formula

[0013] [2] The curable resin composition according to the above item [1], wherein the maleimide resin mixture is obtained by reacting a styrene-maleic anhydride copolymer, 4,4'-methylenebis(2-ethyl-6-methylaniline), and maleic anhydride. [3] The curable resin composition according to item [2] above, wherein the styrene-maleic anhydride copolymer has a weight average molecular weight of 900 or more and less than 10,000. [4] The curable resin composition according to any one of the preceding items [1] to [3], further comprising at least one selected from the group consisting of maleimide resins other than the maleimide resin mixture, polyphenylene ether compounds, compounds having an ethylenically unsaturated bond, cyanate ester resins, polybutadiene and modified products thereof, polystyrene and modified products thereof, and polyethylene and modified products thereof. [5] The curable resin composition according to any one of the above items [1] to [4], further comprising a curing accelerator. [6] The curable resin composition according to any one of the above items [1] to [5], further comprising a photoradical polymerization initiator. [7] The curable resin composition according to the above item [6], which is for use in a resist. [8] The curable resin composition according to any one of items [1] to [6] above, which is for use in a printed wiring board. [9] A varnish comprising the curable resin composition according to any one of the above items [1] to [8] and an organic solvent.

[10] A cured product obtained by curing the curable resin composition according to any one of the above items [1] to [8]. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a curable resin composition having an excellent low dielectric loss tangent. [Brief explanation of the drawings]

[0015] [Figure 1] 1 shows a GPC chart of Synthesis Example 1. [Figure 2] 1 shows a GPC chart of Synthesis Example 2. [Figure 3] 1 shows a GPC chart of Comparative Synthesis Example 1. [Figure 4] Shows the GPC chart of Comparative Synthesis Example 2.

Mode for Carrying Out the Invention

[0022] Here, the GPC area percentage of component (c) indicates the ratio of the GPC peak area representing component (c) to the sum of the GPC peak areas representing the maleimide resin having repeating units of formulae (a) and (b) and the GPC peak areas representing component (c). That is, the GPC area percentage of component (c) is expressed by the following formula: GPC area percentage of component (c) = (GPC peak area showing component (c)) / {(GPC peak area showing maleimide resin having repeating units of formulas (a) and (b)) + (GPC peak area showing component (c))} × 100 (%)

[0023] An organic solvent can be added to the maleimide resin mixture of this embodiment to form a varnish. Examples of organic solvents that can be used include toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. The content of the maleimide resin mixture of this embodiment in the varnish is preferably 30 to 90 wt %, more preferably 40 to 80 wt %.

[0024] The maleimide resin mixture of this embodiment can be produced by reacting a styrene-maleic anhydride copolymer with 4,4'-methylenebis(2-ethyl-6-methylaniline) and maleic anhydride, but the maleimide resin mixture can be produced by reacting 4,4'-methylenebis(2-ethyl-6-methylaniline) with maleic anhydride. Note that bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by formula (c) is produced by reacting 4,4'-methylenebis(2-ethyl-6-methylaniline) with maleic anhydride. Specifically, it can be obtained by a method in which a styrene-maleic anhydride copolymer and 4,4'-methylenebis(2-ethyl-6-methylaniline) are imidized in a solvent in the presence of a catalyst in the first step, and then additional maleic anhydride is added in the second step to maleimide the unreacted 4,4'-methylenebis(2-ethyl-6-methylaniline) to obtain bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by formula (c). The order of steps 1 and 2 is not limited. For example, after the second step of imidizing maleic anhydride and 4,4'-methylenebis(2-ethyl-6-methylaniline) in a solvent in the presence of a catalyst, a styrene-maleic anhydride copolymer may be additionally added to maleimidize the unreacted 4,4'-methylenebis(2-ethyl-6-methylaniline) and the styrene-maleic anhydride copolymer. Alternatively, the styrene-maleic anhydride copolymer and maleic anhydride may be simultaneously reacted with 4,4'-methylenebis(2-ethyl-6-methylaniline). Alternatively, a styrene-maleic anhydride copolymer and 4,4'-methylenebis(2-ethyl-6-methylaniline) may be imidized in a solvent in the presence of a catalyst to obtain a maleimide resin mixture, and then bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by the formula (c) may be added and mixed.

[0025] In the imidization step (the first step), gelation due to three-dimensional crosslinking during the reaction can be prevented by adding an excess of amino groups from 4,4'-methylenebis(2-ethyl-6-methylaniline) per mole of acid anhydride contained in the styrene-maleic anhydride copolymer. In this case, the value (α / β) obtained by dividing the number of moles of amino groups in 4,4'-methylenebis(2-ethyl-6-methylaniline) (α) by the number of moles of acid anhydride in the styrene-maleic anhydride copolymer (β) is preferably in the range of 1.1 to 20, more preferably 1.1 to 15, and even more preferably 1.1 to 10. If the α / β ratio is less than this range, gelation occurs, making production difficult. If the α / β ratio exceeds this range, the amount of polystyrene incorporated decreases, resulting in insufficient improvement in electrical properties. Examples of solvents that can be used include, but are not limited to, water-insoluble 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. Two or more of these solvents may be used in combination. Furthermore, aprotic polar solvents may also be used in combination with the water-insoluble solvents. Examples include dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, and N-methylpyrrolidone. Two or more of these solvents may also 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 to be used in combination. During the reaction, as needed, a catalyst may be used, such as hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, p-toluenesulfonic acid, or methanesulfonic acid; Lewis acids such as aluminum chloride or zinc chloride; solid acids such as activated clay, acid clay, white carbon, zeolite, or silica alumina; or acidic ion exchange resins. These may be used alone or in combination. The amount of catalyst used is usually 0.1 to 0.8 mol, and preferably 0.2 to 0.7 mol, per mol of amino groups in the amine compound used. If the amount of catalyst used is too large, the viscosity of the reaction solution may become too high, making stirring difficult; if the amount is too small, the reaction may proceed slowly.In the second imidization step, maleic anhydride is added in an amount at least equivalent, preferably at least 1.1 equivalents, relative to the molar number of amino groups in the excess 4,4'-methylenebis(2-ethyl-6-methylaniline) added in the first step. This allows all of the remaining 4,4'-methylenebis(2-ethyl-6-methylaniline) to be maleimidized. Furthermore, basic cocatalysts such as triethylamine can be used alone or in combination as a cocatalyst for imidization. When using a catalyst such as sulfonic acid, neutralization with an alkali metal such as sodium hydroxide or potassium hydroxide can be performed before proceeding to the extraction step. For the extraction step, aromatic hydrocarbon solvents such as toluene and xylene can be used alone, or non-aromatic hydrocarbons such as cyclohexane and toluene can be used in combination. After extraction, the organic layer is washed with water until the wastewater becomes neutral, and the solvent is removed using an evaporator or the like to obtain the desired maleimide resin having a polystyrene structure within the molecule.

[0026] Styrene-maleic anhydride copolymers can be obtained by copolymerizing styrene and maleic anhydride. The polymerization method can be any known method, including radical polymerization, coordination polymerization, and various living polymerizations. For example, they can be obtained by reacting styrene and maleic anhydride in toluene in the presence of a radical polymerization initiator. The resulting polymer may be a random polymer or a periodic copolymer, or may be a block polymer or an alternating copolymer. The stereoregularity of the polystyrene segments may be syndiotactic, atactic, isotactic, or the like.

[0027] The weight-average molecular weight (Mw) of the styrene-maleic anhydride copolymer, as determined by gel permeation chromatography (GPC), is preferably 900 or more but less than 10,000, more preferably 1,500 or more but less than 9,000, and particularly preferably 2,000 or more but less than 8,000. The number-average molecular weight (Mn) is preferably 1,000 or more but less than 5,000, and more preferably 1,000 or more but less than 3,000. When the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are less than the upper limit values, gelation can be prevented, and purification by water washing can be facilitated. When the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are equal to or greater than the lower limit values, the target compound does not volatilize during the solvent distillation step.

[0028] 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 but less than 100,000, more preferably 1,000 or more but less than 7,000, and particularly preferably 2,000 or more but less than 6,000. The number-average molecular weight (Mn) is preferably 1,000 or more but less than 5,000, and more preferably 1,000 or more but less than 2,000. It is preferable for the weight-average molecular weight (Mw) and number-average molecular weight (Mn) to be less than the upper limit values, as this results in excellent solvent solubility. It is also preferable for the weight-average molecular weight (Mw) and number-average molecular weight (Mn) to be equal to or greater than the lower limit values, as this results in less volatile content during molding, making molding defects less likely to occur.

[0029] 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 500 g / eq or more but less than 3000 g / eq, more preferably 500 g / eq or more but less than 2000 g / eq, and particularly preferably 600 g / eq or more but less than 1500 g / eq. A maleimide equivalent less than the upper limit described above contains maleimide groups, which are crosslinking components, and are incorporated into the cured network, thereby reducing molding defects and increasing the glass transition temperature (Tg). Furthermore, a maleimide equivalent equal to or greater than the lower limit described above is preferred because the cured product contains fewer highly polar maleimide groups, allowing for control of changes in properties due to water absorption.

[0030] 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 the reaction initiation temperature to be controlled. Controlling the reaction initiation temperature makes it easier to ensure fluidity, prevents impregnation into glass cloth and the like, and facilitates B-staging, such as prepreg formation. If the polymerization reaction proceeds too much during prepreg formation, problems such as difficulty in lamination during the lamination process are likely to occur. Usable polymerization inhibitors include phenol-based, sulfur-based, phosphorus-based, hindered amine-based, nitroso-based, and nitroxyl radical-based polymerization inhibitors. The polymerization inhibitor may be added during or after the synthesis of the maleimide resin mixture of this embodiment. The polymerization inhibitors may be used alone or in combination of two or more. The amount of the polymerization inhibitor used is typically 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 may be used alone or in combination of two or more. In this embodiment, phenol-based, hindered amine-based, nitroso-based, and nitroxyl radical-based inhibitors are preferred.

[0031] 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 and 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-hydroxy-hydrocinnamamide), 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl ) 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, bis(3,5-di-t-butyl-4-hydroxybenzylsulfonate)calcium bisphenols;Examples include polymeric phenols such as 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.

[0032] Specific examples of sulfur-based polymerization inhibitors include dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, and distearyl-3,3'-thiodipropionate.

[0033] Specific examples of phosphorus-based polymerization inhibitors include triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, tris(nonylphenyl) phosphite, diisodecyl pentaerythritol phosphite, tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentane tetrayl bis(octadecyl) phosphite, cyclic neopentane tetrayl bis(2,4-di-t-butylphenyl) phosphite, and cyclic neopentane tetrayl bis(2,4-di-t-butyl-4-methylphenyl) phosphite. phosphites such as bis[2-t-butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl]hydrogenphosphite; 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.

[0034] Specific examples of hindered amine polymerization inhibitors include ADK STAB (registered trademark) LA-40MP, ADK STAB LA-40Si, ADK STAB LA-402AF, ADK STAB LA-87, DEKA STAB LA-82, DEKA STAB LA-81, ADK STAB LA-77Y, ADK STAB LA-77G, ADK STAB LA-72, ADK STAB LA-68, ADK STAB LA-63P, ADK STAB LA-57, and ADK STAB LA-52 (all manufactured by AD Corporation). Examples of the vinyl acrylate copolymer include, but are not limited to, BASF (manufactured by BASF), Chimassorb (registered trademark) 2020FDL, Chimassorb 944FDL, Chimassorb 944LD, Tinuvin (registered trademark) 622SF, Tinuvin PA144, Tinuvin 765, Tinuvin 770DF, Tinuvin XT55FB, Tinuvin 111FDL, Tinuvin 783FDL, and Tinuvin 791FB (all manufactured by BASF).

[0035] Specific examples of the nitroso-based polymerization inhibitor include p-nitrosophenol, N-nitrosodiphenylamine, and the ammonium salt of N-nitrosophenylhydroxyamine (cupferron), and preferably the ammonium salt of N-nitrosophenylhydroxyamine (cupferron).

[0036] Specific examples of nitroxyl radical polymerization inhibitors 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, and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl.

[0037] The curable resin composition of this embodiment can use any known material as the curable resin other than the maleimide resin of this embodiment and component (c). Specific examples include the maleimide resin of this embodiment and maleimide resins other than component (c), phenolic resins, epoxy resins, amine resins, compounds containing ethylenically unsaturated bonds, isocyanate resins, polyamide resins, polyimide resins, cyanate ester resins, propenyl resins, methallyl resins, and activated ester resins. These may be used alone or in combination. Furthermore, in terms of the balance of heat resistance, adhesion, and dielectric properties, it is preferable to include an epoxy resin, a compound containing an ethylenically unsaturated bond, or a cyanate ester resin. The inclusion of these curable resins can improve the brittleness of the cured product and adhesion to metals, thereby suppressing package cracking during reliability tests such as solder reflow and thermal cycling. The amount of the curable resin used is preferably 10 times or less by weight, more preferably 5 times or less by weight, and particularly preferably 3 times or less by weight, relative to the maleimide resin mixture of this embodiment. The lower limit is preferably 0.5 times or more by weight, and more preferably 1 time or more by weight. If the amount is 10 times or less by weight, the effects of the heat resistance and dielectric properties of the maleimide resin mixture of this embodiment can be utilized.

[0038] Examples of the maleimide resin of this embodiment and maleimide resins other than component (c), phenolic resins, epoxy resins, amine resins, compounds containing an ethylenically unsaturated bond, isocyanate resins, polyamide resins, polyimide resins, cyanate ester resins, and active ester resins that can be used include those exemplified below.

[0039] Maleimide resin of the present embodiment and maleimide resins other than component (c): 4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, 2,2'-bis[4-(4-maleimidophenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 4,4'-diphenylether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene), Xylox-type maleimide compounds (anilix maleimide, manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenylaralkyl-type maleimide compounds (solidified by distilling off the solvent under reduced pressure from a resin solution containing the maleimide compound (M2) described in Example 4 of JP 2009-001783 A), bisaminocumylbenzene-type maleimide (maleimide compounds described in WO 2020 / 054601 A), maleimide compounds having an indane structure described in Japanese Patent No. 6629692 or WO 2020 / 217679, and maleimide compounds described in MATERIAL STAGE Vol. 18, No. 12 2019, "Continued Epoxy Resin CAS Number Story - Curing Agent CAS Number Memorandum, Part 31, Bismaleimide (1)" and MATERIAL STAGE Vol. 19, No. 2 2019, "Continued Epoxy Resin CAS Number Story - Curing Agent CAS Number Memorandum, Part 32, Bismaleimide (2)."

[0040] Phenolic resins: Polycondensates of phenols (phenol, alkyl-substituted phenols, aromatic-substituted phenols, hydroquinone, resorcinol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) with various aldehydes (formaldehyde, acetaldehyde, alkyl aldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural, etc.), polycondensates of phenols and various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydrofuran, etc.) phenolic resins obtained by polycondensation of phenols and substituted biphenyls (4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl, etc.) or substituted phenyls (1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene, etc.); polycondensates of bisphenols and various aldehydes; and polyphenylene ether compounds.

[0041] Any known polyphenylene ether compound may be used, but from the viewpoint of heat resistance and electrical properties, a polyphenylene ether compound having an ethylenically unsaturated double bond is preferred, and a polyphenylene ether compound having an acrylic group, a methacrylic group, or a styrene structure is more preferred. 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 Company, 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 to be insufficient. On the other hand, if the molecular weight is more than 5000, the melt viscosity increases and sufficient fluidity cannot be obtained, which tends to result in molding defects. In addition, the reactivity decreases, the curing reaction takes a long time, and the amount of unreacted material not incorporated into the curing system increases, which tends to lower the glass transition temperature of the cured product and reduce the heat resistance of the cured product. When the number average molecular weight of the polyphenylene ether compound is 500 to 5000, it is possible to maintain excellent dielectric properties while exhibiting excellent heat resistance, moldability, etc. The number average molecular weight here can be specifically measured using gel permeation chromatography, etc.

[0042] The polyphenylene ether compound may be obtained by a polymerization reaction or by a redistribution reaction of a high-molecular-weight polyphenylene ether compound having a number-average molecular weight of approximately 10,000 to 30,000. Alternatively, these compounds may be used as raw materials and reacted with a compound having an ethylenically unsaturated double bond, such as methacryl chloride, acrylic chloride, or chloromethylstyrene, to impart radical polymerizability. A polyphenylene ether compound obtained by a redistribution reaction may be obtained, for example, 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 cause a redistribution reaction. Such polyphenylene ether compounds obtained by a redistribution reaction are preferred because they have hydroxyl groups derived from phenolic compounds at both ends of the molecular chain that contribute to curing, thereby maintaining even higher heat resistance. Furthermore, functional groups can be introduced at both ends of the molecular chain even after modification with a compound having an ethylenically unsaturated double bond. Furthermore, polyphenylene ether compounds obtained by a polymerization reaction are preferred because they exhibit excellent fluidity.

[0043] In the case of polyphenylene ether compounds obtained by polymerization, the molecular weight of the polyphenylene ether compound can be adjusted by adjusting the polymerization conditions, etc. In the case of polyphenylene ether compounds obtained by redistribution, the molecular weight of the resulting polyphenylene ether compound can be adjusted by adjusting the conditions, etc. of the redistribution reaction. More specifically, adjusting the amount of the phenolic compound used in the redistribution reaction can be considered. That is, the greater the amount of the phenolic compound, the lower the molecular weight of the resulting polyphenylene ether compound. In this case, poly(2,6-dimethyl-1,4-phenylene ether) or the like can be used as the high-molecular-weight polyphenylene ether compound that undergoes the redistribution reaction. The phenolic compound used in the redistribution reaction is not particularly limited, but preferred are, for example, polyfunctional phenolic compounds having two or more phenolic hydroxyl groups per molecule, such as bisphenol A, phenol novolac, and cresol novolac. These compounds may be used alone or in combination of two or more.

[0044] The content of the polyphenylene ether compound is not particularly limited, but is preferably 10 to 90 wt %, more preferably 20 to 80 wt %, based on the total weight of the curable resin components. A polyphenylene ether compound content of 10 to 90 wt % is preferable in that it not only has excellent heat resistance, etc., but also allows a cured product to fully exhibit the excellent dielectric properties of the polyphenylene ether compound.

[0045] Epoxy resins: glycidyl ether epoxy resins obtained by glycidylating the above-mentioned phenolic resins and alcohols, alicyclic epoxy resins such as 4-vinyl-1-cyclohexene diepoxide and 3,4-epoxycyclohexylmethyl-3,4'-epoxycyclohexanecarboxylate, glycidylamine epoxy resins such as tetraglycidyldiaminodiphenylmethane (TGDDM) and triglycidyl-p-aminophenol, and glycidyl ester epoxy resins.

[0046] Amine resins: diaminodiphenylmethane, diaminodiphenyl sulfone, isophoronediamine, naphthalenediamine, aniline novolak, orthoethylaniline novolak, aniline resins obtained by reacting aniline with xylylene chloride, and aniline and substituted biphenyls (4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, etc.) or substituted phenyls (1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene, etc.) described in Japanese Patent No. 6429862.

[0047] Compounds containing an ethylenically unsaturated bond: polycondensates of the above-mentioned phenolic resins and halogenated compounds containing an ethylenically unsaturated bond (chloromethylstyrene, allyl chloride, methallyl chloride, acrylic acid chloride, allyl chloride, etc.), polycondensates of phenols containing an ethylenically unsaturated bond (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) and halogenated compounds (4,4'-bis(methoxymethyl)-1,1'-biphenyl, 1,4-bis(chloromethyl)benzene, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuric chloride, etc.), polycondensates of epoxy resins or alcohols and substituted or unsubstituted acrylates (acrylate, methacrylate, etc.), styrene resins, allyl Group-containing compounds, acenaphthyl group-containing compounds (acenaphthylene, etc.), isocyanuric acid derivatives (TAIC manufactured by Mitsubishi Chemical Corporation, MA-DGIC, DA-MGIC, MeDAIC, L-DAIC, DD-1 manufactured by Shikoku Kasei, etc.), maleimide compounds (phenylmaleimide, 4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, 2,2'-bis[4-(4-maleimidophenoxy) (si) phenyl) propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 4,4'-diphenyl ether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene), Zylok type maleimide resin (Anilix Maleimide, manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenylaralkyl type maleimide resin (a resin solution containing the maleimide resin (M2) described in Example 4 of JP 2009-001783 A, solidified by distilling off the solvent under reduced pressure), bisaminocumylbenzene type maleimide (maleimide resin described in WO 2020 / 054601 A).

[0048] Isocyanate resins: aromatic diisocyanates such as p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and naphthalene diisocyanate; aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate, norbornene diisocyanate, and lysine diisocyanate; polyisocyanates such as biuret compounds of one or more types of isocyanate monomers or isocyanate compounds obtained by trimerizing the above diisocyanate compounds; and polyisocyanates obtained by a urethanization reaction between the above isocyanate compounds and polyol compounds.

[0049] Polyamide resin: A polymer made primarily from one or more amino acids (6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, para-aminomethylbenzoic acid, etc.) and lactams (ε-caprolactam, ω-undecanelactam, ω-laurolactam); or a polymer made primarily from one or more diamines and one or more dicarboxylic acids. Diamines: aliphatic diamines such as ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-diaminopentane, and 2-methyl-1,8-diaminooctane; alicyclic diamines such as cyclohexanediamine, bis-(4-aminocyclohexyl)methane, and bis(3-methyl-4-aminocyclohexyl)methane; and aromatic diamines such as xylylenediamine. Dicarboxylic acids: aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodiumsulfoisophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; and dialkyl esters and dichlorides of these dicarboxylic acids.

[0050] Polyimide resin: A polycondensation product of the above diamine and tetracarboxylic dianhydride. Tetracarboxylic acid dianhydrides: 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2 dicarboxylic acid anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 2,2',3,3'-benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride carboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethylidene-4,4'-diphthalic dianhydride, 2,2'-propylidene-4,4'-diphthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic dianhydride, 4,4'-oxydiphthalic dianhydride, thio-4,4'-diphthalic dianhydride Anhydride, sulfonyl-4,4'-diphthalic 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 dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-Naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic 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) dianhydride, methylene-4,4'-bis(cyclohexane-1,2-dicarboxylic) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic) dianhydride, 1,1-ethylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic) dianhydride hydrate, 2,2-propylidene-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]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, rel-[1S,5R,6R]-3-oxabi Cyclo[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 anhydride, ethylene glycol-bis-(3,4-dicarboxylic anhydride phenyl) ether, 4,4'-biphenyl bis(trimellitic acid monoester acid anhydride), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride.

[0051] Cyanate ester resin: A cyanate ester compound obtained by reacting a phenolic resin with a cyanogen halide. Specific examples include, but are not limited to, dicyanatobenzene, tricyanatobenzene, dicyanatonaphthalene, dicyanatobiphenyl, 2,2-bis(4-cyanatophenyl)propane (BisA-OCN, manufactured by Mitsubishi Gas Chemical Company, Inc.), bis(4-cyanatophenyl)methane, bis(3,5-dimethyl-4-cyanatophenyl)methane, 2,2-bis(3,5-dimethyl-4-cyanatophenyl)propane, 2,2-bis(4-cyanatophenyl)ethane, 2,2-bis(4-cyanatophenyl)hexafluoropropane, bis(4-cyanatophenyl)sulfone, bis(4-cyanatophenyl)thioether, phenol novolac cyanate, and phenol-dicyclopentadiene co-condensates in which the hydroxyl groups have been converted to cyanate groups. Furthermore, the cyanate ester compound, the synthesis method of which is described in Japanese Patent Application Laid-Open No. 2005-264154, is particularly preferred as the cyanate ester compound because it has low moisture absorption, flame retardancy, and excellent dielectric properties. The cyanate ester resin may contain a catalyst such as zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octoate, tin octoate, lead acetylacetonate, dibutyltin maleate, or commercially available product 18% Octope (registered trademark) Zn (Hope Pharmaceutical Co., Ltd.) to trimerize the cyanate group and form a sym-triazine ring, as needed. The catalyst is typically used in an amount of 0.0001 to 0.10 parts by weight, and preferably 0.00015 to 0.0015 parts by weight, per 100 parts by weight of the total weight of the curable resin composition.

[0052] Active ester resin: A compound having one or more active ester groups per molecule can be used as a curing agent for a curable resin other than the maleimide resin mixture of this embodiment, such as an epoxy resin, if necessary. Preferred active ester resins include compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. The active ester resin is preferably one obtained by a condensation reaction between at least one of a carboxylic acid compound and a thiocarboxylic acid compound and at least one of a hydroxy compound and a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester resin obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester resin obtained from a carboxylic acid compound and at least one of a phenol compound and a naphthol compound is preferred. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalene, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolak. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by condensing one dicyclopentadiene molecule with two phenol molecules. Preferred examples of the active ester resin include active ester resins containing a dicyclopentadiene-type diphenol structure, active ester resins containing a naphthalene structure, active ester resins containing an acetylated product of phenol novolac, and active ester resins containing a benzoylated product of phenol novolac. Among these, active ester resins containing a naphthalene structure and active ester resins containing a dicyclopentadiene-type diphenol structure are more preferred. The "dicyclopentadiene-type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene. Commercially available active ester resins include, for example, "EXB9451," "EXB9460," "EXB9460S," "HPC-8000-65T," "HPC-8000H-65™," "EXB-8000L-65™," and "EXB-8150-65T" (manufactured by DIC Corporation) as active ester resins containing a dicyclopentadiene-type diphenol structure; "UNIFINER (registered trademark) series" (manufactured by Unitika Ltd.) as active ester resins containing a bisphenol A-type structure; and "EXB9451," "EXB9460S," "HPC-8000H-65™," "EXB-8000L-65™," and "EXB-8150-65T" (manufactured by DIC Corporation ... Examples include "EXB9416-70BK" (manufactured by DIC Corporation); "DC808" (manufactured by Mitsubishi Chemical Corporation) as an activated ester resin containing an acetylated product of phenol novolac; "YLH1026," "YLH1030," and "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as activated ester resins containing a benzoylated product of phenol novolac; "DC808" (manufactured by Mitsubishi Chemical Corporation) as an activated ester resin which is an acetylated product of phenol novolac; and "EXB-9050L-62M" (manufactured by DIC Corporation) as an activated ester resin containing a phosphorus atom.

[0053] The curable resin composition of the present embodiment can also be used in combination with a curing accelerator (curing catalyst) to improve the curability. Specific examples of curing accelerators that can be used include radical polymerization initiators, which are preferably used for the purpose of promoting self-polymerization of radically polymerizable curable resins such as olefin compounds and maleimide resins, or radical polymerization with other components. Examples of the radical polymerization initiator that can be used 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-cumylperoxyneodecanoate, t-butylperoxyneodecanoate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-amylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, and t-amylperoxy-3,5,5-trimethylhexanoate. Examples of known curing accelerators include alkyl peresters 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-butyl peroxyoctoate, and lauroyl peroxide; and azo compounds such as azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), and 2,2'-azobis(2,4-dimethylvaleronitrile), but are not particularly limited to these. Ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, percarbonates, etc. are preferred, and dialkyl peroxides are more preferred.The amount of radical polymerization initiator added is preferably 0.01 to 5 parts by weight, 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 does not sufficiently elongate during the polymerization reaction.

[0054] Furthermore, if necessary, a curing accelerator other than the radical polymerization initiator may be added or used in combination. Specific examples of the curing accelerator that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole, tertiary amines such as 2-(dimethylaminomethyl)phenol and 1,8-diaza-bicyclo(5,4,0)undecene-7, phosphines such as triphenylphosphine, quaternary ammonium salts such as tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, and hexadecyltrimethylammonium hydroxide, and triphenylammonium salts such as tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, and hexadecyltrimethylammonium hydroxide. Examples of suitable curing accelerators include quaternary phosphonium salts such as benzylbenzylphosphonium salts, triphenylethylphosphonium salts, and tetrabutylphosphonium salts (the counter ions of the quaternary salts can be halogens, organic acid ions, hydroxide ions, etc., but are not particularly limited; organic acid ions and hydroxide ions are particularly preferred), and transition metal compounds (transition metal salts) such as zinc compounds such as tin octoate, zinc carboxylate (zinc 2-ethylhexanoate, zinc stearate, zinc behenate, zinc myristylate), and zinc phosphate esters (zinc octylphosphate, zinc stearylphosphate, etc.). The curing accelerator is used in an amount of 0.01 to 5.0 parts by weight per 100 parts by weight of the epoxy resin, as needed.

[0055] The curable resin composition of this embodiment may contain a phosphorus-containing compound as a flame retardant-imparting component. The phosphorus-containing compound may be a reactive type or an additive type. Specific examples of the phosphorus-containing compound include phosphate esters such as trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylylenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixylylenyl phosphate, 1,3-phenylenebis(dixylylenyl phosphate), 1,4-phenylenebis(dixylylenyl phosphate), and 4,4'-biphenyl(dixylylenyl phosphate); 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; 10(2,5- Examples of suitable compounds include phosphanes such as (dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; phosphorus-containing epoxy compounds obtained by reacting epoxy resins with the active hydrogen of the phosphanes; and red phosphorus. However, phosphate esters, phosphanes, or phosphorus-containing epoxy compounds are preferred, with 1,3-phenylenebis(dixylylenyl phosphate), 1,4-phenylenebis(dixylylenyl phosphate), 4,4'-biphenyl(dixylylenyl phosphate), or phosphorus-containing epoxy compounds being particularly preferred. The content of the phosphorus-containing compound is preferably in the range of 0.1 to 0.6 (weight ratio) (phosphorus-containing compound) / (total epoxy resin). If the ratio is less than 0.1, flame retardancy is insufficient, while if it is more than 0.6, there is a risk of adverse effects on the moisture absorption and dielectric properties of the cured product.

[0056] Furthermore, a light stabilizer may be added to the curable resin composition of this embodiment as needed. As the light stabilizer, a hindered amine light stabilizer (HALS) or the like is suitable. Although there is no particular limitation on HALS, representative examples include polycondensates of 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, polycondensates of dimethyl succinate and 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine, 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-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)butylamine], and the like. bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butyl malonate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1-octyloxy-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. Only one type of HALS may be used, or two or more types may be used in combination.

[0057] Furthermore, a binder resin can be blended into the curable resin composition of this embodiment as needed. Examples of binder resins include, but are not limited to, 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 blended is preferably within a range that does not impair the flame retardancy and heat resistance of the cured product, and is preferably 0.05 to 50 parts by weight, more preferably 0.05 to 20 parts by weight, per 100 parts by weight of the resin component, as needed.

[0058] Furthermore, the curable resin composition of this embodiment may contain, as needed, inorganic fillers such as 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 spherical or crushed versions of these. Particularly when a curable resin composition for semiconductor encapsulation is obtained, the amount of the inorganic filler used is typically 80 to 92 wt %, and preferably 83 to 90 wt %, of the curable resin composition.

[0059] The curable resin composition of the present embodiment may contain known additives as needed. Specific examples of usable additives include polybutadiene and modified products thereof, modified products of acrylonitrile copolymers, polyphenylene ether, polystyrene and modified products thereof, polyethylene and modified products thereof, 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, phthalocyanine green, etc. The amount of these additives to be added is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, and particularly preferably 10 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 modified products thereof, polyphenylene ether, polystyrene and modified products thereof, polyethylene and modified products thereof, fluororesin, etc. are preferred. From the viewpoint of electrical properties, adhesion, and low water absorption, polystyrene and modified products thereof, polyethylene and modified products thereof, and polybutadiene and modified products thereof are preferred. Specific examples include butadiene-based thermoplastic elastomers such as styrene-butadiene copolymers (SBR: RICON-100, RICON-181, RICON-184, all manufactured by Cray Valley, etc.) and acrylonitrile-butadiene copolymers; styrene-butadiene-styrene copolymers (SBS), hydrogenated styrene-butadiene-styrene copolymers, styrene-isoprene-styrene copolymers (SIS), hydrogenated styrene-isoprene-styrene copolymers, hydrogenated styrene-(butadiene / isoprene)-styrene copolymers, etc.; and styrene-ethylene-propylene-styrene copolymers. These styrene-based thermoplastic elastomers may be used alone or in combination of two or more. 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 particularly preferred because they have higher heat resistance and are less susceptible to oxidative degradation.Specifically, 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, Hybra 7125 (hydrogenated), Hybra 7215F, Hybra 7311F, Septon The weight-average molecular weight of the styrene-based thermoplastic elastomer is not particularly limited as long as it is 10,000 or greater. However, if it is too large, compatibility with polyphenylene ether compounds, low-molecular-weight components with weight-average molecular weights of approximately 50 to 1,000, and oligomer components with weight-average molecular weights of approximately 1,000 to 5,000 is impaired, making it difficult to ensure blending and solvent stability. Therefore, a weight-average molecular weight of approximately 10,000 to 300,000 is preferred. Generally, compounds containing heteroatoms such as oxygen and nitrogen, such as bismaleimides and polymaleimides, have difficulty ensuring compatibility with low-polarity compounds, such as compounds composed primarily or exclusively of hydrocarbons, among the additives and curable resin components mentioned above, due to their polarity. 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 (i.e., it has few polar groups), and therefore exhibits excellent compatibility with materials with low polarity and low dielectric tangents, as well as compounds composed exclusively of hydrocarbons.

[0060] The curable resin composition of this embodiment can be obtained by uniformly mixing the above components in a predetermined ratio, and is typically pre-cured at 130 to 180°C for 30 to 500 seconds, and then post-cured at 150 to 250°C for 2 to 15 hours, allowing the curing reaction to proceed sufficiently to obtain the cured product of this embodiment. Alternatively, the components of the curable resin composition can be uniformly dispersed or dissolved in a solvent or the like, and the solvent can be removed before curing.

[0061] The curable resin composition of this embodiment thus obtained 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 requiring moisture resistance, heat resistance, and high adhesion. 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. It can also be used in molding materials, composite materials, coating materials, adhesives, 3D printing, and other fields. Solder reflow resistance is particularly beneficial in semiconductor encapsulation.

[0062] The semiconductor device may be encapsulated with the curable resin composition of the present embodiment, and examples of the semiconductor device include a DIP (dual in-line package), a QFP (quad flat package), a BGA (ball grid array), a CSP (chip size package), a SOP (small outline package), a TSOP (thin small outline package), and a TQFP (thin quad flat package).

[0063] The method for preparing the curable resin composition of this embodiment is not particularly limited, and the components may be simply mixed uniformly, or may be prepolymerized. For example, the maleimide resin mixture of this embodiment may be prepolymerized by heating it 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, a curing agent such as an epoxy resin, an amine compound, a maleimide-based compound, a cyanate ester compound, a phenolic resin, or an acid anhydride compound, and other additives may be added to form a prepolymer. The components may be mixed or prepolymerized using, for example, an extruder, kneader, or rolls in the absence of a solvent, or a reaction kettle equipped with a stirrer in the presence of a solvent.

[0064] To achieve uniform mixing, the materials are kneaded at a temperature in the range of 50 to 100°C using a device such as a kneader, roll, or planetary mixer to obtain a uniform resin composition. The resulting resin composition is then pulverized and molded into cylindrical tablets using a molding machine such as a tablet machine, or into granular powder or powder-like molded products. Alternatively, these compositions can be melted on a surface support and molded into sheets 0.05 mm to 10 mm thick to obtain molded curable resin compositions. The resulting molded products are non-sticky at 0 to 20°C, and exhibit little loss in fluidity or curability even when stored at -25 to 0°C for one week or more. The resulting molded article can be molded into a cured product using a transfer molding machine or a compression molding machine.

[0065] An organic solvent can be added to the curable resin composition of this embodiment to form 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 heated and dried to obtain a prepreg. This prepreg can then be hot-press molded to form a cured product of the curable resin composition of this embodiment. The solvent used here typically accounts for 10 to 70 wt %, preferably 15 to 70 wt %, of the mixture of the curable resin composition of this embodiment and the solvent. Furthermore, if the composition is in liquid form, a cured curable resin containing carbon fiber can be obtained directly, for example, by RTM (resin transfer molding).

[0066] The curable resin composition of this embodiment can also be used as a modifier for film-type resin compositions. Specifically, it can be used to improve flexibility in the B-stage. Such a film-type resin composition can be obtained as a sheet-type adhesive by applying the curable resin composition of this embodiment as a varnish onto a release film, removing the solvent under heating, and then performing B-stage conversion. This sheet-type adhesive can be used as an interlayer insulating layer in a multilayer substrate or the like.

[0067] The curable resin composition of this embodiment can be heated and melted to reduce its viscosity, and then impregnated into reinforcing fibers such as glass fibers, carbon fibers, polyester fibers, polyamide fibers, and alumina fibers to obtain a prepreg. Specific examples include 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; and organic fibers such as polyparaphenylene terephthalamide (Kevlar®, manufactured by DuPont), wholly aromatic polyamides, polyesters, and polyparaphenylene benzoxazole, polyimides, and carbon fibers, but are not limited thereto. The shape of the substrate is not particularly limited, but examples include woven fabrics, nonwoven fabrics, rovings, and chopped strand mats. Known weaving methods for woven fabrics include plain weave, saddle-weave, and twill weave, and these known methods can be appropriately selected and used depending on the intended application and performance. Also suitable are woven fabrics that have been subjected to fiber-opening treatment and glass woven fabrics that have been surface-treated with a silane coupling agent or the like. The thickness of the substrate is not particularly limited, but is preferably about 0.01 to 0.4 mm. Also, a prepreg can be obtained by impregnating reinforcing fibers with the varnish and drying them by heating.

[0068] The laminate of this embodiment includes one or more prepregs. The laminate is not particularly limited as long as it includes one or more prepregs, and may include any other layer. The method for manufacturing the laminate is not particularly limited and can be any generally known method. For example, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, an autoclave molding machine, or the like can be used to mold the metal foil-clad laminate. The prepregs are laminated together and then heated and pressurized to obtain a laminate. The heating temperature is not particularly limited, but is preferably 65 to 300°C, more preferably 120 to 270°C. The pressure applied is also not particularly limited, but too high a pressure can make it difficult to adjust the resin solid content of the laminate, resulting in unstable quality. On the other hand, too low a pressure can result in bubbles or poor adhesion between the laminate layers. Therefore, the pressure is preferably 2.0 to 5.0 MPa, more preferably 2.5 to 4.0 MPa. The laminate of this embodiment includes a layer made of metal foil, making it suitable for use as a metal foil-clad laminate, as described below. The prepreg is cut into a desired shape and laminated with copper foil or the like as needed. The laminate is then heated and cured while applying pressure by press molding, autoclave molding, sheet winding molding, or the like, to obtain an electrical and electronic laminate (printed wiring board) or a carbon fiber reinforced material.

[0069] The cured product of this embodiment can be used in various applications such as molding materials, adhesives, composite materials, paints, etc. The cured product of the curable resin composition described in this embodiment exhibits excellent heat resistance and dielectric properties, and is therefore suitable for use in electrical and electronic components such as encapsulants for semiconductor elements, encapsulants for liquid crystal display elements, encapsulants for organic EL elements, printed wiring boards, and build-up laminates, as well as composite materials for lightweight, high-strength structural materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics.

[0070] (Another embodiment) The cured product of this embodiment can also be used as a resist film, an interlayer insulating material for build-up construction, or an optical waveguide in a printed circuit board, or as an electrical, electronic, or optical substrate such as an optoelectronic board or optical board. Specific examples of these include computers, home appliances, and mobile devices. The thickness of the cured product layer is typically about 0.5 to 160 μm, and preferably about 1 to 100 μm.

[0071] The curable resin composition of this embodiment preferably contains a photopolymerization initiator. The photopolymerization initiator is preferably a photoradical polymerization initiator or a photocationic polymerization 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. If the content is less than 0.001 part by mass, photocuring may be insufficient, and if the content is more than 20 parts by mass, dielectric properties may deteriorate. Preferred examples of photopolymerization initiators are listed below, but the present invention is not limited to these. These may be used alone or in combination of two or more.

[0072] Photoradical polymerization initiator: The photoradical polymerization initiator is not particularly limited as long as it is a compound that generates radicals and initiates a chain polymerization reaction when irradiated with ultraviolet light or visible light. Examples of the photoradical polymerization initiator include benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, diethylthioxanthone, benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propane, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, camphorquinone, 9-fluorenone, and diphenyl disulfide. Specific examples include IRGACURE (registered trademark) 651, 184, 2959, 127, 907, 369, 379EG, 819, 784, 754, 500, OXE-01, OXE-02, OXE-03, OXE-04, DAROCUR (registered trademark) 1173, LUCIRIN (trademark) TPO (all manufactured by BASF Japan Ltd.), SEIKUOL (registered trademark) Z, BZ, BEE, BIP, BBI (all manufactured by Seiko Chemical Co., Ltd.), and KAYACURE (registered trademark) DETX-S (manufactured by Nippon Kayaku Co., Ltd.). Among these, preferred are the oxime ester initiators IRGACURE OXE01, OXE02, OXE03, and OXE04.

[0073] Photocationic polymerization initiator: The photocationic polymerization initiator is not particularly limited as long as it is a compound that generates cationic species such as Bronsted acids or Lewis acids upon irradiation with ultraviolet or visible light, but examples include aromatic iodonium complex salts and aromatic sulfonium complex salts. Specific examples of aromatic iodonium complex salts include diphenyliodonium tetrakis(pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, di(4-nonylphenyl)iodonium hexafluorophosphate, tolylcumyliodonium tetrakis(pentafluorophenyl)borate (manufactured by Rhodia, trade name: Rhodosil 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 San-Apro Co., Ltd., trade name: CPI-101A), thiophenyldiphenylsulfonium tris(pentafluoroethyl)trifluorophosphate (manufactured by San-Apro Co., Ltd., trade name: CPI-210S), 4-{4-(2-chlorobenzoyl)phenylthio}phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate (manufactured by ADEKA Corporation, trade name: SP-172), and a mixture of aromatic sulfonium hexafluoroantimonates containing 4-thiophenyldiphenylsulfonium hexafluoroantimonate (manufactured by ACETO Corporation). Examples of suitable sulfonium compounds include triphenylsulfonium tris(trifluoromethanesulfonyl)methanide (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).Among these, aromatic sulfonium complex salts are preferred in the present invention because they have high vertical rectangular processability and high thermal stability in the photosensitive image formation process. Among these, 4-{4-(2-chlorobenzoyl)phenylthio}phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate, a mixture of aromatic sulfonium hexafluoroantimonates containing 4-thiophenyldiphenylsulfonium hexafluoroantimonate, and tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl)borate are particularly preferred.

[0074] The curable resin composition of this embodiment can be used by a known method. For example, the curable resin composition of the present invention, the viscosity of which 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 form 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 protection film such as a SiN film or SiO2 film has been formed.

[0075] 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, a coating method using a spin coater is preferably employed. Furthermore, the film thickness of the film-like curable resin composition can be adjusted as desired by adjusting the concentration of the curable resin composition and the coating thickness, and is not particularly limited. For example, when used as a protective film for semiconductor elements 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, the underlying elements and circuits tend to be insufficiently protected, while if it exceeds 50 μm, fine pattern formation tends to be difficult. In the present invention, even if the film thickness is 10 μm or more (preferably 10 to 20 μm), it is possible to form a fine pattern, and it is possible to form a pattern in which the aspect ratio of the opening diameter (Via diameter) of the through-hole formed by exposure and development described below is 0.3 or more (more preferably 0.5 or more).

[0076] Next, the film-like curable resin composition thus obtained is exposed to light through a mask having a predetermined pattern, thereby photopolymerizing the curable resin composition of the present invention. Examples of the exposure method include contact exposure and reduced projection exposure. The exposure wavelength is preferably ultraviolet to visible light of 200 to 500 nm, and a standard reduced projection exposure machine (stepper) can be used. Furthermore, from the viewpoint of enabling the formation of a fine pattern, the exposure wavelength is more preferably 256 to 436 nm, and even more preferably 256 to 365 nm. The exposure dose is not particularly limited, but is preferably 100 to 5,000 mJ / cm. 2 is preferably 300 to 3000 mJ / cm 2 It is more preferable that:

[0077] Next, development is performed to dissolve and remove the unexposed portions of the film-like curable resin composition after exposure, thereby obtaining a polymerized film (polymer) having a predetermined pattern. Specifically, in the exposed portions, radicals or cationic species generated from the photopolymerization initiator upon light irradiation cause crosslinking of component (A) and other compounds, rendering them insoluble in the developer. In contrast, the unexposed portions dissolve in the developer, and by utilizing the difference in solubility between the exposed and unexposed portions in the developer, a polymerized film having a pattern of through-holes with a predetermined opening diameter (Via diameter) can be obtained. In addition to using the above-mentioned solvents, the developer may further contain an alcoholic solvent such as methanol, ethanol, or propanol to adjust solubility during development. Examples of the development method include spraying, puddling, and dipping.

[0078] It is also preferable to further rinse the polymer film having the predetermined pattern obtained by the development with an organic solvent such as cyclopentanone or a mixed solvent of cyclopentanone and ethanol. From the viewpoints of suppressing the occurrence of surface roughness and facilitating dimensional design, it is preferable that the polymer film after the development has a residual film ratio of 90% or more. In the present invention, the residual film ratio refers to the ratio of the film thickness of the polymer film after development to the film thickness of the film-like curable resin composition after drying (before exposure) (film thickness of the polymer film after development / film thickness of the film-like curable resin composition after drying (before exposure)).

[0079] Next, the polymer film having the predetermined pattern obtained by the development can be heated and cured as necessary to obtain a cured film (cured product) having the 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 the present invention, the curing temperature refers to the temperature required to thermally cure functional groups remaining unreacted during the exposure by thermal reaction.

[0080] Thus, by using the curable resin composition of the present invention, a cured film having a fine pattern can be obtained. The pattern preferably has an aspect ratio of the opening diameter (Via diameter) of the formed through-holes of 0.3 or more, more preferably 0.5 or more. In the present invention, the opening diameter can be determined by measurement using an optical microscope or a scanning electron microscope (SEM).

[0081] The cured product obtained by photocuring or photothermal curing (curing using a combination of photocuring and thermal curing) using the curable resin composition of the present invention can be suitably used for at least one film selected from the group consisting of a surface protection film for a semiconductor element, an interlayer insulating film, and an insulating film for a redistribution layer. Furthermore, the curable resin composition of the present invention is particularly effective when such a film requires a thickness of 10 μm or more and patterning is required so that the aspect ratio of the opening diameter (Via diameter) of the through-hole is 0.3 or more (more preferably 0.5 or more). [Example]

[0082] The present invention will now be described in more detail with reference to examples. Unless otherwise specified, all parts are by weight. However, the present invention is not limited to these examples.

[0083] The various analytical methods used in the examples are described below. <Gel Permeation Chromatography (GPC)> Equipment: ACQUITY APC system (Waters) Column: Guard column SHODEX GPC KF-601 (2 columns), KF-602 KF-602.5, KF-603 Flow rate: 1.23ml / min. Column temperature: 25℃ Solvent used: THF (tetrahydrofuran) Detector: RI (differential refractive index detector)

[0084] [Synthesis Example 1] A flask equipped with a thermometer, condenser, and stirrer was charged with 30.1 parts toluene, 10.0 parts n-methylpyrrolidone, 6.35 parts 4,4'-methylenebis(2-ethyl-6-methylaniline), and 0.25 parts methanesulfonic acid. After confirming that the solution was homogeneous, 19.8 parts styrene-maleic anhydride copolymer (acid value: 85, Mn: 1,979, Mw: 3,088) was added to the dropping funnel. The styrene-maleic anhydride copolymer was added to the flask over 5 hours at 120°C, and the reaction was continued for 10 hours at 120°C. After cooling, 15.0 parts toluene, 5.0 parts n-methylpyrrolidone, and 3.56 parts maleic anhydride were added to the flask, and the reaction was continued under reflux for 8 hours. After cooling, the reaction solution was diluted with 285 parts toluene, and the organic layer was washed six times with 100 parts of 10 wt% brine and three times with 100 parts of warm water. The solvent was distilled off under reduced pressure with heating to obtain the desired maleimide resin mixture (M-1) as a brown solid resin. The GPC chart of the resulting compound is shown in Figure 1. The proportion of component (c), calculated from the peak area ratio, was 17.7% in terms of GPC area percentage. From the acid value and molecular weight of the raw material, styrene-maleic anhydride copolymer, m was calculated to be 26.7 and n was calculated to be 2.3.

[0085] [Synthesis Example 2] A flask equipped with a thermometer, condenser, and stirrer was charged with 26.9 parts toluene, 8.95 parts n-methylpyrrolidone, 17.30 parts 4,4'-methylenebis(2-ethyl-6-methylaniline), and 0.69 parts methanesulfonic acid. After confirming that the solution was homogeneous, 36.4 parts styrene-maleic anhydride copolymer (acid value: 150, Mn: 2,454, Mw: 4,997) was added and the mixture was reacted at 115±2°C for 15 hours. After cooling, 13.4 parts toluene, 9.0 parts n-methylpyrrolidone, and 14.4 parts maleic anhydride were added, and the reaction was continued under reflux for 6 hours. After cooling, the reaction solution was diluted with 645 parts toluene, and the organic layer was washed four times with 245 parts of 10 wt% brine and three times with 245 parts of warm water. The solvent was distilled off under reduced pressure with heating to obtain the desired maleimide resin mixture (M-2) as a toluene solution. The GPC chart of the resulting compound is shown in Figure 2. The proportion of component (c), calculated from the peak area ratio, was 17.2% in terms of GPC area percentage. From the acid value and molecular weight of the raw material styrene-maleic anhydride copolymer, m was calculated to be 41.5 and n to be 6.7.

[0086] [Comparative Synthesis Example 1] A flask equipped with a thermometer, condenser, and stirrer was charged with 75.0 parts of toluene, 25.0 parts of n-methylpyrrolidone, 8.47 parts of 4,4'-methylenebis(2-ethyl-6-methylaniline), 0.17 parts of methanesulfonic acid, and 18.7 parts of styrene-maleic anhydride copolymer (acid value: 60, Mn: 6,686, Mw: 11,295), and the mixture was reacted at 120°C for 2 hours. After cooling, 5.88 parts of maleic anhydride was added, and the reaction was continued under reflux for 6 hours. After cooling, the reaction solution was diluted with 50 parts of toluene, and the organic layer was washed five times with 100 parts of hot water. The solvent was removed by distillation under reduced pressure with heating to obtain the desired maleimide resin mixture (M-3) as a brown solid resin. The GPC chart of the resulting compound is shown in Figure 3. The proportion of component (c) calculated from the peak area ratio was 37.7% in terms of GPC area percentage. From the acid value and molecular weight of the raw material, styrene-maleic anhydride copolymer, m was calculated to be 92.4 and n to be 5.4.

[0087] [Comparative Synthesis Example 2] A flask equipped with a thermometer, condenser, and stirrer was charged with 75.0 parts of toluene, 25.0 parts of n-methylpyrrolidone, 14.12 parts of 4,4'-methylenebis(2-ethyl-6-methylaniline), 0.28 parts of methanesulfonic acid, and 23.4 parts of styrene-maleic anhydride copolymer (acid value: 120, Mn: 5,984, Mw: 14,768), and the mixture was reacted at 120 °C for 3 hours. After cooling, 9.81 parts of maleic anhydride was added, and the reaction was continued under reflux for 8 hours. After cooling, the reaction solution was diluted with 100 parts of toluene, and the organic layer was washed five times with 100 parts of warm water. The solvent was removed by distillation under heating and reduced pressure to obtain the target compound (M-4) as a brown solid resin (Mn: 1210, Mw: 8644). The GPC chart of the resulting compound is shown in Figure 4. The proportion of component (c) calculated from the peak area ratio was 37.8%. From the acid value and molecular weight of the raw material styrene-maleic anhydride copolymer, m was calculated to be 116.2 and n was calculated to be 14.4.

[0088] [Comparative Synthesis Example 3] A flask equipped with a thermometer, condenser, and stirrer was charged with 75.0 parts of toluene, 25.0 parts of n-methylpyrrolidone, 5.65 parts of 4,4'-methylenebis(2-ethyl-6-methylaniline), 0.11 parts of methanesulfonic acid, and 18.7 parts of styrene-maleic anhydride copolymer (acid value: 60, Mn: 6,686, Mw: 11,295), and the mixture was allowed to react at 120°C for 2 hours. After cooling, 2.94 parts of maleic anhydride was added, and the reaction was continued under reflux for 17 hours. After cooling, the reaction solution was diluted with 50 parts of toluene, and an attempt was made to wash the organic layer with 100 parts of warm water, but the organic and aqueous layers did not separate.

[0089] <Solvent solubility and storage stability tests> The maleimide resin mixtures M-1, M-3, and M-4 obtained in Synthesis Example 1 and Comparative Synthesis Examples 1 and 2, and the maleimide resin (Mn: 2126, Mw: 11527) described in Example 12 of Japanese Patent No. 7208705 were diluted with toluene to a resin content of 60 wt %. As a result, the maleimide resin mixtures M-1, M-3, and M-4 obtained in Synthesis Example 1 and Comparative Synthesis Examples 1 and 2 were dissolved in toluene, but the maleimide resin described in Example 12 of Japanese Patent No. 7208705 was not dissolved in toluene. Next, the maleimide resin mixtures M-1, M-3, and M-4 obtained in Synthesis Example 1 and Comparative Synthesis Examples 1 and 2 were diluted with toluene to a resin content of 60% by weight, and 1 g of each was placed in a 6 cc screw cap vial. The bottles were sealed with lids and allowed to stand in a refrigerator at 5.0 to 10.0°C for 24 hours, after which the presence or absence of crystal precipitation was visually confirmed. Those with no crystal precipitation were evaluated as ◯ (good storage stability), and those with precipitation were evaluated as × (poor storage stability). The results are shown in Table 1. The maleimide resin described in Example 12 of Japanese Patent No. 7208705 did not dissolve in toluene under the above conditions, so the amount of toluene was increased to confirm its solubility. It was confirmed that the maleimide resin did not dissolve in toluene at a resin content of 60 to 20% by weight, but did dissolve in toluene at a resin content of 10% by weight. Therefore, 1 g of the maleimide resin solution described in Example 12 of Japanese Patent No. 7208705, diluted with toluene to a resin content of 10% by weight, was placed in a 6 cc screw cap vial, sealed with a lid, and allowed to stand at room temperature for 24 hours. The presence or absence of crystal precipitation was then visually confirmed. The presence of precipitation was confirmed.

[0090] [Table 1]

[0091] From the results in Table 1, it was confirmed that the maleimide resin mixture obtained in Synthesis Example 1 had excellent solvent solubility and storage stability in the solution state (varnish).

[0092] [Examples 1 to 7] A 250 μm thick cushion paper with a 150 mm × 150 mm cutout in the center was placed on the first copper foil. A 5.0 g sample of the curable resin composition formulated according to the ratios shown in Table 2 was placed in the center of the frame, and a second copper foil was placed on top of the cushion paper and sample. The cushion paper and sample sandwiched between the first and second copper foils were heated and pressurized in a vacuum heating press to form a sample, which was then cured at 220°C for 2 hours. The first and second copper foils were then etched using ferric chloride to obtain a cured film. The dielectric loss tangent and glass transition temperature (Tg) of the cured film were measured using the methods described below and are shown in Table 2.

[0093] <Dielectric loss tangent test> The test was carried out at 25°C using a 10 GHz cavity resonator manufactured by AET Co., Ltd., using a cavity resonator perturbation method. The test was carried out on a sample with a width of 2.5 mm, length of 50 mm, and a thickness of 0.25 mm. Dynamic Mechanical Analysis (DMA) Dynamic viscoelasticity measuring device: DMA Q800 (TA instruments) Measurement temperature range: 30 to 350°C Heating rate: 2°C / min Frequency: 10Hz Sample size: Width 5mm x Length 40mm x Thickness 0.25mm Criterion: The temperature at which the loss factor (tan δ) = (loss modulus G") / (storage modulus G') is maximum is defined as the glass transition temperature (Tg).

[0094] [Table 2]

[0095] M-5 (maleimide resin obtained by the method described in Synthesis Example 2 of WO 2022 / 210433, from which the solvent was distilled off by heating under reduced pressure) NC-3000 (epoxy resin, manufactured by Nippon Kayaku Co., Ltd.) Unifiner W-575 (active ester, manufactured by Unitika Ltd.) SA-9000-111 (polyphenylene ether compound with methacrylate structure, manufactured by Sabic) OPE-2St 1200 (polyphenylene ether compound with a styrene structure, manufactured by Mitsubishi Gas Chemical Company, Inc.) OPE-2St 2200 (polyphenylene ether compound with a styrene structure, manufactured by Mitsubishi Gas Chemical Company, Inc.) Acenaphthylene (manufactured by JFE Chemical Corporation) Phenylmaleimide (Tokyo Chemical Industry Co., Ltd.) BisA-OCN (2,2-bis(4-cyanatophenyl)propane, manufactured by Mitsubishi Gas Chemical Company, Inc.) DCP (Dicumyl peroxide, manufactured by Kayaku Nouryon Co., Ltd.) 18% Octope Zn (Hope Pharmaceuticals Co., Ltd.)

[0096] From the results in Table 2, it was confirmed that Examples 1 to 7 had excellent low dielectric tangents. The attenuation rate of a signal flowing through the dielectric material that makes up a printed wiring board is proportional to the dielectric loss tangent. Since signal attenuation directly generates heat and causes a temperature rise, a low dielectric loss tangent is important for printed wiring board materials.

[0097] [Example 8] The photosensitive resin composition formulated in the proportions shown in Table 3 was applied to rolled copper foil BHY-82F-HA-V2 (manufactured by JX Metals Corporation) using an applicator to a thickness of 20 μm. The coating was dried in a hot air dryer at 80°C for 30 minutes, and then irradiated with an ultraviolet ray irradiator (manufactured by GS YUASA: CS 30L-1) at 500 mJ / cm. 2 The copper foil was then etched using ferric chloride to obtain a cured film. The dielectric loss tangent of the cured film was measured using the method described below, and the results are shown in Table 3. [Example 9] The photosensitive resin composition formulated in the proportions shown in Table 3 was applied to rolled copper foil BHY-82F-HA-V2 (manufactured by JX Metals Corporation) using an applicator to a thickness of 20 μm. The coating was dried in a hot air dryer at 80°C for 30 minutes, and then irradiated with an ultraviolet ray irradiator (manufactured by GS YUASA: CS 30L-1) at 500 mJ / cm. 2 The coating was cured by irradiating it with ultraviolet light at 220°C for 60 minutes. After heating and curing in an oven at 220°C for 60 minutes, the copper foil was etched with ferric chloride to obtain a cured film. The dielectric loss tangent of the cured film was measured using the method described below, and the results are shown in Table 3.

[0098] <Dielectric loss tangent test> The test was carried out at 25°C using a 10 GHz cavity resonator manufactured by AET Co., Ltd., using a cavity resonator perturbation method. The sample size was 1.7 mm wide x 100 mm long, and the thickness was 1.7 mm.

[0099] [Table 3]

[0100] OXE-04 (manufactured by BASF Japan Ltd.)

[0101] Conventional solder resists have a dielectric loss tangent of approximately 0.017 to 0.032 (see Table 1 in "Latest Technological Trends in Insulating Materials for Printed Wiring Boards" (Journal of the Japan Institute of Electronics Packaging, Vol. 21, No. 3, 2018, pp. 202-206).) The results in Table 3 show that Examples 8 and 9 have a lower dielectric loss tangent than conventional solder resists. [Industrial Applicability]

[0102] The curable resin composition of the present invention and its cured product are useful for applications such as insulating materials for electric and electronic components (such as highly reliable semiconductor encapsulation materials), laminates (such as printed wiring boards, BGA substrates, and build-up substrates), resist films, printed circuit boards as optical waveguides, electric / electronic / optical substrates such as optoelectronic substrates and optical substrates, adhesives (such as conductive adhesives), various composite materials including CFRP, paints, and 3D printing.

Claims

1. A curable resin composition containing a maleimide resin mixture consisting of a maleimide resin having repeating units represented by the following formulas (a) and (b) and bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by the following formula (c): a curable resin composition, wherein the content of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by formula (c) is 5.0 to 30.0 area % in terms of GPC area percentage, relative to the total amount of the maleimide resin mixture. 【Chemical 1】 In the above formula (a), m is the average number of repeats, and is 0<m<200. In the above formula (2), n is the average number of repeats, and is 0<n<100. (a) and (b) are each connected with *, and the repeat positions may be random. 【Chemistry 2】

2. 2. The curable resin composition according to claim 1, wherein the maleimide resin mixture is obtained by reacting a styrene-maleic anhydride copolymer, 4,4'-methylenebis(2-ethyl-6-methylaniline), and maleic anhydride.

3. 3. The curable resin composition according to claim 2, wherein the styrene-maleic anhydride copolymer has a weight average molecular weight of 900 or more and less than 10,000.

4. 2. The curable resin composition according to claim 1, further comprising at least one selected from the group consisting of maleimide resins other than the maleimide resin mixture, polyphenylene ether compounds, compounds having an ethylenically unsaturated bond, cyanate ester resins, polybutadiene and modified products thereof, polystyrene and modified products thereof, and polyethylene and modified products thereof.

5. The curable resin composition according to claim 1 , further comprising a curing accelerator.

6. The curable resin composition according to claim 1 , further comprising a photoradical polymerization initiator.

7. The curable resin composition according to claim 6, which is for use in a resist.

8. The curable resin composition according to claim 1, which is for use in a printed wiring board.

9. A varnish comprising the curable resin composition according to any one of claims 1 to 8 and an organic solvent.

10. A cured product obtained by curing the curable resin composition according to claim 1 .

Images