Curable resin composition, prepreg, and cured product thereof

Abstract

To provide a curable resin composition excellent in low linear expansion coefficient and low dielectric characteristics.SOLUTION: A curable resin composition contains a maleimide compound (A) having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), and an amine compound (B), and satisfies the following formula (I): 1.5 ≤ (mass content of maleimide compound (A) / maleimide equivalents) / (mass content of amine compound (B) / amine equivalents) ≤ 2.5 Formula (I) wherein R1 and R2 are each independently an alkyl group having 1 to 20 carbon atoms or an optionally substituted aromatic group having 1 to 20 carbon atoms, p is an integer of 0 to 3, and q is an integer of 0 to 4. ) SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition, a prepreg, and a cured product thereof, which are suitable for use in electrical and electronic components such as semiconductor encapsulants, printed wiring boards, and build-up laminates, 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 as their fields of use expand. For example, while semiconductor chips were previously mounted on metal lead frames, semiconductor chips with advanced processing capabilities, such as CPUs, are increasingly being mounted on laminates made of polymer materials. As the speed of devices such as CPUs increases and clock frequencies become higher, signal propagation delays and transmission losses become problems, and wiring boards are being required to have low dielectric constants and low dielectric dissipation factors.

[0003] In terms of advances in communications technology, momentum for 5G has been building in recent years, and it is predicted that there will be an explosive increase in communications devices that use not only Sub6 but also quasi-millimeter and millimeter waves above 10 GHz, especially above 28 GHz, and base stations, antennas, and communications devices will require substrate materials that can handle high frequencies. These substrate materials place importance on high dielectric properties (especially dielectric dissipation factor) to prevent a decrease in transmission speed, and materials that can be used stably in these ranges are required.

[0004] Additionally, in the semiconductor-related field, development of package substrates required for mounting chips is progressing, leading to advances in thinner substrates. In addition, in recent years, efforts have been made to increase the size of the chips mounted thereon, thereby increasing the density and integration, thereby enabling faster and larger-capacity information transmission, and as a result, package substrates are also becoming larger. As package substrates become thinner and larger, differences in the linear expansion coefficient between them and the chips can lead to warping and the risk of cracking. Therefore, resin materials with a low linear expansion coefficient (low CTE) are being sought for the resin materials widely used in substrates.

[0005] However, epoxy resins, which have been widely used in various fields, are no longer able to meet the required dielectric properties and linear expansion coefficient. Maleimide compounds have been proposed as alternatives to epoxy resins. While maleimide compounds exhibit excellent dielectric properties and linear expansion coefficients, their use alone is difficult due to their brittle cured products and high water absorption.

[0006] Therefore, other materials are used as curing agents together with maleimide compounds, specifically polyphenylene ether compounds. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2023-013860 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-080493 Summary of the Invention [Problem to be solved by the invention]

[0008] However, although polyphenylene ether compounds exhibit excellent dielectric properties when used as curing agents, their linear expansion coefficients are still insufficient due to the large distance between functional groups in polyphenylene ether compounds.

[0009] Therefore, there is a demand for a resin composition and a cured product thereof that use a maleimide compound and have both excellent dielectric properties and a linear expansion coefficient.

[0010] Patent Document 1 discloses a composition of a bifunctional maleimide compound and a polyphenylene ether compound, but the linear expansion coefficient is not sufficient. Patent Document 2 discloses a composition containing a maleimide compound, an aromatic diamine compound, a phenolic catalyst, and silica, but the dielectric properties are not sufficient.

[0011] The present invention has been made in view of the above points, and an object of the present invention is to provide a curable resin composition that is excellent in low linear expansion coefficient and low dielectric properties. [Means for solving the problem]

[0012] A curable resin composition according to an embodiment of the present invention is a curable resin composition containing a maleimide compound (A) having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), and an amine compound (B), and satisfying the following formula (I): 1.5≦(mass of maleimide compound (A) content / maleimide equivalent) / (mass of amine compound (B) content / amine equivalent)≦2.5 Formula (I)

[0013] [ka]

[0014] (In formulas (1) and (2), R1 and R2 each independently represent an alkyl group having 1 to 20 carbon atoms or an aromatic group having 1 to 20 carbon atoms which may have a substituent, p is an integer of 0 to 3, and q is an integer of 0 to 4.)

[0015] In the present application, "(Numerical value 1) to (Numerical value 2)" indicates that the upper and lower limit values ​​are included. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a curable resin composition having a low linear expansion coefficient and excellent low dielectric properties, and a cured product thereof. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a GPC chart of Synthesis Example 1. [Figure 2] 1 is a GPC chart of Synthesis Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0018] The curable resin composition of the present invention contains a maleimide compound (A) having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), and an amine compound (B).

[0019] [ka]

[0020] In formulas (1) and (2), R1 and R2 each independently represent an alkyl group having 1 to 20 carbon atoms or an aromatic group having 1 to 20 carbon atoms which may have a substituent, more preferably an alkyl group having 1 to 5 carbon atoms or an aromatic group having 1 to 10 carbon atoms which may have a substituent, and even more preferably an alkyl group having 1 to 3 carbon atoms. p is an integer of 0 to 3, and q is an integer of 0 to 4.

[0021] The maleimide compound (A) is preferably a maleimide compound represented by the following formula (3).

[0022] [ka]

[0023] In formula (3), R1 and R2 each independently represent an alkyl group having 1 to 20 carbon atoms or an aromatic group having 1 to 20 carbon atoms which may have a substituent, more preferably an alkyl group having 1 to 5 carbon atoms or an aromatic group having 1 to 10 carbon atoms which may have a substituent, and even more preferably an alkyl group having 1 to 3 carbon atoms. p is an integer of 0 to 3, and q is an integer of 0 to 4. n is the number of repetitions, the average value of which is 1. <n<5である。

[0024] In the formula (3), the value of n can be calculated from the number average molecular weight determined by measuring the maleimide resin by gel permeation chromatography (GPC, detector: RI) or from the area ratio of each separated peak.

[0025] In the formula (3), when n=1, the solubility in solvents is low, and when n is 5 or more, the flowability during molding is poor, and the properties of the cured product cannot be fully exhibited.

[0026] In the formula (3), the content of the n=1 isomer as determined by GPC analysis (RI) is preferably 98 area % or less, more preferably 20 to 90 area %, even more preferably 30 to 80 area %, and particularly preferably 40 to 80 area %. When the content of the n=1 isomer is 98 area % or less, the heat resistance is good. In addition, the crystallinity is reduced and the solvent solubility is improved. On the other hand, when the lower limit of the n=1 isomer is 20 area % or more, the viscosity of the resin solution is reduced and the impregnation property is improved. In addition, since the solvent can be removed at low temperature when the solid is extracted, self-polymerization is less likely to occur and handling is easier.

[0027] Increasing the proportion of asymmetric structures with different orientations relative to the maleimide group in the maleimide compound represented by formula (3) improves solvent solubility and also improves the low dielectric properties of the cured product. The orientation ratio in the n=1 isomer in formula (3) can be determined by HPLC analysis (225 nm), and the ortho-para isomer preferably accounts for 30 area% or more and less than 60 area%, more preferably 35 area% or more and less than 55 area%, and particularly preferably 40 area% or more and less than 55 area%, of the total amount of the n=1 isomer.

[0028] The softening point of the maleimide compound (A) is preferably 50 to 150° C., more preferably 80 to 120° C., even more preferably 90 to 120° C., and particularly preferably 95 to 120° C. The melt viscosity at 150° C. is 0.05 to 100 Pa·s, preferably 0.1 to 40 Pa·s.

[0029] Hereinafter, a method for producing the maleimide compound represented by the formula (3) will be described, but the method is not limited to this method.

[0030] [Method of producing aromatic amine resin] The maleimide compound represented by the formula (3) can use an aromatic amine resin represented by the following formula (4) as a precursor.

[0031] [ka]

[0032] In formula (4), R1, R2, p, q, and n have the same meanings as in formula (3).

[0033] The method for producing the aromatic amine resin represented by formula (4) is not particularly limited. For example, in Japanese Patent Publication No. 4-75222, aniline and m-diisopropenylbenzene or m-di(α-hydroxyisopropyl)benzene are reacted in the presence of an acidic catalyst at 180 to 250°C to obtain the n=1 isomer in formula (4) as the main component. The n=1 isomer includes three isomers: symmetric compounds with the same orientation relative to two aniline molecules, such as 1,3-bis(p-aminocumyl)benzene and 1,3-bis(o-aminocumyl)benzene, and asymmetric compounds with different orientation relative to two aniline molecules, such as 1-(o-aminocumyl)-3-(p-aminocumyl)benzene. Furthermore, n=2 to 5 isomers are also produced as minor components, and in Japanese Patent Publication No. 4-75222, these are purified by crystallization to obtain 1,3-bis(p-aminocumyl)benzene with a purity of 98%. Furthermore, in Japanese Patent Publication No. 6-37465, 1,3-bis(p-aminocumyl)benzene is maleimidized to synthesize N,N'-(1,3-phenylene-di-(2,2-propylidene)-di-p-phenylene)bismaleimide, resulting in a crystalline product. However, heating is required to dissolve this in a solvent, and crystals precipitate within several hours if the product is left at room temperature after heating. Therefore, crystals may precipitate when preparing a resin composition, and the higher the concentration of N,N'-(1,3-phenylene-di-(2,2-propylidene)-di-p-phenylene)bismaleimide, the greater the likelihood of crystallization. To produce printed wiring boards and composites, glass cloth or carbon fiber is impregnated with varnish to adhere the resin. However, if crystals precipitate, the impregnation process becomes impossible. On the other hand, raising the temperature to maintain the soluble state accelerates the reaction of the composition, shortening the usable life of the varnish.

[0034] Examples of acidic catalysts used in synthesizing the aromatic amine resin represented by formula (4) include hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, zinc chloride, ferric chloride, aluminum chloride, p-toluenesulfonic acid, and methanesulfonic acid. In the present invention, protonic acids such as hydrochloric acid, p-toluenesulfonic acid, and methanesulfonic acid are preferred. These may be used alone or in combination. The amount of catalyst used is preferably 1 to 12 mass%, more preferably 1 to 10 mass%, and particularly preferably 1 to 7 mass%, relative to 100 mass% of the aniline used. If the amount exceeds 12 mass%, the desired compound with an asymmetric structure will be scarce, and compounds with a symmetric structure will be preferentially produced. On the other hand, if the amount is less than 1%, not only will the reaction proceed slowly, but the reaction may not be completed, which is undesirable.

[0035] The reaction may be carried out using an organic solvent such as toluene or xylene, or without a solvent, as needed. For example, after adding an acidic catalyst to a mixed solution of anilines and a solvent, if the catalyst contains water, it is preferable to remove the water from the system by azeotropy. Diisopropenylbenzene or di(α-hydroxyisopropyl)benzene is then added, and the reaction is then carried out while removing the solvent from the system by heating to 140-190°C, preferably 160-190°C, for 5-50 hours, preferably 5-30 hours. If the reaction temperature is too high, the asymmetric structure recombines after formation, resulting in the formation of a symmetric structure, which results in the failure to achieve the desired solvent solubility and electrical properties. When di(α-hydroxyisopropyl)benzene is used, water is by-produced, and is removed from the system by azeotropy with the solvent during heating. After the reaction is complete, the acidic catalyst is neutralized with an alkaline aqueous solution. A water-insoluble organic solvent is added to the oil layer, and the mixture is repeatedly washed with water until the wastewater becomes neutral. The solvent and excess anilines are then removed under reduced pressure after heating. When activated clay or ion exchange resin is used, the reaction mixture is filtered after the reaction to remove the catalyst. Depending on the reaction temperature and the type of catalyst, diphenylamine may be produced as a by-product, and it is therefore preferable to remove it as needed. The diphenylamine derivative is removed to 1% by mass or less, preferably 0.5% by mass or less, and more preferably 0.2% by mass or less, by means of high temperature and high vacuum, or by steam distillation.

[0036] Examples of anilines used in the production of the aromatic amine resin represented by the formula (4) include aniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 2-ethylaniline, 3-ethylaniline, 4-ethylaniline, 2,3-dimethylaniline, 2,4-dimethylaniline, 2,5-dimethylaniline, 2,6-dimethylaniline, 3,4-dimethylaniline, 3,5-dimethylaniline, 2-propylaniline, 3-propylaniline, and 4-propylaniline. , 2-isopropylaniline, 3-isopropylaniline, 4-isopropylaniline, 2-ethyl-6-methylaniline, 2-sec-butylaniline, 2-tert-butylaniline, 4-butylaniline, 4-sec-butylaniline, 4-tert-butylaniline, 2,3-diethylaniline, 2,4-diethylaniline, 2,5-diethylaniline, 2,6-diethylaniline, 2-isopropyl-6-methylaniline, 4-aminobiphenyl, etc. These may be used alone or in combination of two or more.

[0037] [Maleimide resin manufacturing method] The maleimide compound represented by the formula (3) can be obtained by subjecting the aromatic amine resin represented by the formula (4) obtained by the above process to an addition or dehydration condensation reaction with maleic acid or maleic anhydride (hereinafter also referred to as "maleic anhydride") in the presence of a solvent and a catalyst.

[0038] The solvent used in the reaction is preferably a water-insoluble solvent, since water generated during the reaction must be removed from the system. Examples of the solvent include, but are not limited to, 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.

[0039] In addition to the water-insoluble solvent, an aprotic polar solvent can also be used in combination. Examples include dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, and N-methyl-2-pyrrolidone, and two or more of these can be used in combination. When using an aprotic polar solvent, it is preferable to use one with a higher boiling point than the water-insoluble solvent used in combination.

[0040] The catalyst used in the reaction is an acid catalyst, and is not particularly limited, but examples thereof include p-toluenesulfonic acid, hydroxy-p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, phosphoric acid, etc. The amount of the acid catalyst used is usually 0.1 to 10% by mass, and preferably 1 to 5% by mass, based on the aromatic amine resin.

[0041] For example, the aromatic amine resin represented by the formula (4) is dissolved in toluene and N-methyl-2-pyrrolidone, and maleic anhydride is added thereto to generate an amic acid. Then, p-toluenesulfonic acid is added, and the reaction is carried out under reflux conditions while removing the generated water from the system.

[0042] Alternatively, maleic anhydride is dissolved in toluene, and an N-methyl-2-pyrrolidone solution of the aromatic amine resin represented by the formula (4) is added under stirring to generate an amic acid, and then p-toluenesulfonic acid is added to the solution, and the reaction is carried out under reflux conditions while removing the generated water from the system.

[0043] Alternatively, maleic anhydride is dissolved in toluene, p-toluenesulfonic acid is added, and the N-methyl-2-pyrrolidone solution of the aromatic amine resin represented by formula (4) is added dropwise under stirring and reflux, while the water that forms an azeotropic mixture is removed from the system and the toluene is returned to the system to carry out the reaction (this is the first-stage reaction).

[0044] In either method, maleic anhydride is usually used in an amount of 1.0 to 3.0 times equivalent, preferably 1.2 to 2.0 times equivalent, relative to the amino groups of the aromatic amine resin represented by the formula (4).

[0045] To reduce the amount of uncyclized amic acid, water is added to the reaction solution after the maleimidation reaction listed above, separating the solution into a resin solution layer and an aqueous layer. Excess maleic acid, maleic anhydride, aprotic polar solvent, catalyst, etc., which are dissolved in the aqueous layer, are removed by liquid separation, and the same procedure is repeated to thoroughly remove the excess maleic acid, maleic anhydride, aprotic polar solvent, and catalyst. A catalyst is added again to the maleimide resin solution in the organic layer from which the excess maleic acid, maleic anhydride, aprotic polar solvent, and catalyst have been removed, and the dehydration and cyclization reaction of the remaining amic acid is carried out again under heated reflux conditions, yielding a maleimide resin solution with a low acid value (this is the second-stage reaction).

[0046] The re-dehydration ring-closing reaction time is usually 1 to 5 hours, preferably 1 to 3 hours, and the aforementioned aprotic polar solvent may be added if necessary. After completion of the reaction, the reaction mixture is cooled and repeatedly washed with water until the wash water becomes neutral. Thereafter, the water is removed by azeotropic dehydration under heating and reduced pressure, and the solvent may be distilled off or another solvent may be added to prepare a resin solution of the desired concentration, or the solvent may be completely distilled off to obtain a solid resin.

[0047] The maleimide equivalent of the maleimide compound (A) is preferably 250 g / eq. to 1000 g / eq., more preferably 260 g / eq. to 900 g / eq., and particularly preferably 270 g / eq. to 800 g / eq. Here, the maleimide equivalent is the value obtained by dividing the molecular weight of the maleimide compound by the number of maleimide groups. The maleimide equivalent of the maleimide compound (A) can be measured, for example, by the measurement method described in JP-A-2020-187012. Furthermore, if the maleimide equivalent can be calculated from the structural formula and the number of functional groups, that value may be used.

[0048] The curable resin composition of the present invention contains an amine compound (B).

[0049] The amine compound (B) used in the present invention is preferably a compound having two or more amino groups in one molecule. Examples of the amine compound include diaminodiphenylmethane, isophoronediamine, naphthalenediamine, aniline novolak (a reaction product of aniline and formalin), N-methylaniline novolak (a reaction product of N-methylaniline and formalin), orthoethylaniline novolak (a reaction product of orthoethylaniline and formalin), a reaction product of 2-methylaniline and formalin, a reaction product of 2,6-diisopropylaniline and formalin, a reaction product of 2,6-diethylaniline and formalin, a reaction product of 2-ethyl-6-ethylaniline and formalin, a reaction product of 2,6-dimethylaniline and formalin, and aniline obtained by the reaction of aniline and xylylene chloride. Examples of the amine compound include, but are not limited to, the reaction products of aniline and substituted biphenyls (such as 4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl) described in Japanese Patent No. 6429862, reaction products of aniline and substituted phenyls (such as 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene), 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, reaction products of aniline and diisopropenylbenzene, and dimer diamine. These compounds may be used alone or in combination of two or more. From the viewpoint of reactivity, aromatic amine compounds are preferred, and aromatic amine compounds provide superior storage stability of the curable resin composition before curing compared to aliphatic amines or alicyclic amines. Furthermore, alkyl group-substituted aromatic amine compounds are more preferred, and aromatic amine compounds having an alkyl group at the ortho- or para-position of the amino group are particularly preferred. By using an alkyl group-substituted aromatic amine compound, more preferably an ortho- or para-substituted aromatic amine compound, the electron donating ability of the amino group can be improved, thereby improving reactivity. Therefore, excellent curability can be achieved even under milder conditions than aliphatic amines and alicyclic amines.

[0050] The amine equivalent of the amine compound (B) is preferably 50 g / eq. to 400 g / eq., more preferably 75 g / eq. to 300 g / eq., and particularly preferably 90 g / eq. to 250 g / eq. Here, the amine equivalent is the value obtained by dividing the molecular weight of the amine compound by the number of amino groups. If the amine equivalent is less than 50 g / eq., the crosslinking density will be too high, resulting in poor toughness of the cured product. On the other hand, if the amine equivalent is more than 400 g / eq., heat resistance may be reduced. When the amine equivalent is within the above range, a cured product can be obtained without deterioration in toughness or heat resistance.

[0051] The curable resin composition of the present invention satisfies the following formula (I). 1.5≦(mass of maleimide compound (A) content / maleimide equivalent) / (mass of amine compound (B) content / amine equivalent)≦2.5 Formula (I)

[0052] The value of (mass of maleimide compound (A) content / maleimide equivalent) / (mass of amine compound (B) content / amine equivalent) is more preferably 1.6 or more and 2.4 or less, and particularly preferably 1.7 or more and 2.3 or less. If it is less than 1.5, i.e., if the amount of amine compound used is too large, the crosslink density will be too high, resulting in poor toughness of the cured product or no cured product being obtained. On the other hand, if it is more than 2.5, i.e., if the amount of amine compound used is too small, the degree of cure will be insufficient, resulting in poor heat resistance of the cured product or no cured product being obtained. By satisfying formula (I), a cured product can be obtained without poor toughness or heat resistance.

[0053] The curable resin composition of the present invention has a low linear expansion coefficient and excellent low dielectric properties. The linear expansion coefficient is preferably 70 ppm / °C or less, more preferably 65 ppm / °C or less, and particularly preferably 60 ppm / °C or less. A high linear expansion coefficient increases the difference in linear expansion coefficient between thin substrates such as package substrates and the semiconductor chips and copper foils used therein, which can lead to warping and possible breakage. Therefore, a low linear expansion coefficient is required for thin substrates. Regarding dielectric properties, substrate materials used in high-frequency regions must have a low dielectric dissipation factor to minimize signal transmission loss. When measured at 10 GHz, the dielectric dissipation factor is preferably 0.0035 or less, more preferably 0.0033 or less, and even more preferably 0.0032 or less.

[0054] [Curing accelerator] The curability of the resin composition of the present invention can be improved by adding a curing accelerator. As the curing accelerator, an anionic curing accelerator that accelerates the curing reaction by generating anions upon irradiation with ultraviolet light or visible light or heating, or a cationic curing accelerator that accelerates the curing reaction by generating cations upon irradiation with ultraviolet light or visible light or heating, is preferred.

[0055] Examples of anionic curing accelerators include imidazole compounds. Examples of imidazole compounds include 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole. Commercially available products include Curesol SIZ (manufactured by Shikoku Chemicals Co., Ltd., the same applies hereinafter), Curesol C11Z, Curesol C17Z, Curesol 1,2DMZ, Curesol 2PZ, Curesol 2P4MZ, Curesol 1B2MZ, Curesol 1B2PZ, and Curesol. Examples of suitable curing agents include, but are not limited to, Curazol 2MZ-CN, Curazol C11Z-CN, Curazol 2E4MZ-CN, Curazol 2PZ-CN, Curazol 2PZCNS-PW, Curazol 2MZ-A, Curazol C11Z-A, Curazol 2E4MZ-A, Curazol 2MA-OK, Curazol 2PHZ-PW, Curazol 2P4MHZ-PW, and Curazol 2MZA-PW. These may be used alone or in combination, and may be manufactured or commercially available products.

[0056] The content of the imidazole compound is preferably 1 to 10 parts by mass, more preferably 1 to 6 parts by mass, and even more preferably 1 to 4 parts by mass, per 100 parts by mass of the total of the maleimide compound (A) and the amine compound (B). If the amount of the imidazole compound added is less than 1 part by mass, there is a risk of a decrease in curability and copper foil adhesion, whereas if it is more than 10 parts by mass, there is a risk of a decrease in dielectric properties, water absorption properties, and thermal decomposition properties.

[0057] Examples of anionic curing accelerators other than the imidazole compound include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene, with 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene being preferred. Other examples include phosphines such as triphenylphosphine, and quaternary ammonium salts such as tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, and hexadecyltrimethylammonium hydroxide, but are not limited thereto. These may be used alone or in combination.

[0058] Examples of cationic curing accelerators include quaternary phosphonium salts such as triphenylbenzylphosphonium salt, triphenylethylphosphonium salt, and tetrabutylphosphonium salt (the counter ion of the quaternary salt may be a halogen, an organic acid ion, a hydroxide ion, or the like, but is not particularly limited, with organic acid ions and hydroxide ions being particularly preferred), and transition metal compounds (transition metal salts) such as cobalt naphthenate, copper naphthenate, lead acetylacetonate, copper acetylacetonate, dibutyltin maleate, manganese naphthenate, tin octoate, zinc carboxylates (zinc 2-ethylhexanoate, zinc stearate, zinc behenate, zinc myristate), and zinc phosphates (zinc octylphosphate, zinc stearylphosphate). These may be used alone or in combination.

[0059] The curing accelerator may be added to the resin composition of the present invention in an amount of 0.01 to 5.0 parts by mass, if necessary, relative to 100 parts by mass of the total of the maleimide compound (A) and the amine compound (B).

[0060] [Inorganic filler] The resin composition of the present invention may contain an inorganic filler. Examples of inorganic fillers include, but are not limited to, 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, as well as inorganic fillers obtained by forming these into spherical or crushed shapes. These fillers may be used alone or in combination.

[0061] When a curable resin composition for semiconductor encapsulation is obtained, the amount of inorganic filler used is preferably 80 to 92 parts by mass, and more preferably 83 to 90 parts by mass, per 100 parts by mass of the curable resin composition. When a curable resin composition for interlayer insulating layer formation, or a substrate material such as a copper-clad laminate, prepreg, or RCC is obtained, the amount of inorganic filler used is preferably 5 to 80 parts by mass, and more preferably 10 to 60 parts by mass, per 100 parts by mass of the curable resin composition.

[0062] [Polymerization initiator] The curability of the curable resin composition of the present invention can be improved by adding a polymerization initiator. The polymerization initiator is a compound capable of polymerizing olefin functional groups such as ethylenically unsaturated bonds, and examples thereof include olefin metathesis polymerization initiators, anionic polymerization initiators, cationic polymerization initiators, and radical polymerization initiators. Among these, it is preferable to use a radical polymerization initiator that has curability and appropriate stability. A radical polymerization initiator is a compound that generates radicals upon irradiation with ultraviolet or visible light or heating, thereby initiating a chain polymerization reaction. Usable radical polymerization initiators include organic peroxides, azo compounds, and benzopinacols. Organic peroxides are preferred because they are effective in controlling the curing temperature, suppress outgassing, and minimize the impact of decomposition products on electrical properties.

[0063] Examples of the organic peroxides 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-butylperoxymethyl ... Examples of the peroxycarbonates include, but are not limited to, alkyl peresters such as di-2-ethylhexyl peroxydicarbonate, t-amylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, and t-amylperoxybenzoate, peroxycarbonates such as di-2-ethylhexyl peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, t-butylperoxyisopropyl carbonate, and 1,6-bis(t-butylperoxycarbonyloxy)hexane, t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyoctoate, and lauroyl peroxide. These peroxycarbonates may be used alone or in combination. Among the above organic peroxides, ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, percarbonates, etc. are preferred, with dialkyl peroxides being more preferred.

[0064] Examples of the azo compounds include, but are not limited to, azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2,4-dimethylvaleronitrile), etc. These compounds may be used alone or in combination.

[0065] The amount of polymerization initiator added is preferably 0.01 to 5 parts by mass, particularly preferably 0.01 to 3 parts by mass, per 100 parts by mass of the total of the maleimide compound (A) and the amine compound (B). If the amount of polymerization initiator used is less than 0.01 part by mass, there is a risk that the molecular weight will not be sufficiently elongated during the polymerization reaction, and if it is more than 5 parts by mass, there is a risk that low dielectric properties such as dielectric constant and dielectric loss tangent will be impaired.

[0066] [Polymerization inhibitor] The curable resin composition of the present invention may contain a polymerization inhibitor. The inclusion of a polymerization inhibitor improves storage stability and enables control of the reaction initiation temperature. 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.

[0067] The amount of the polymerization inhibitor used is preferably 0.008 to 1 part by mass, and more preferably 0.01 to 0.5 parts by mass, when the total amount of the maleimide compound (A) and the amine compound (B) is 100 parts by mass.

[0068] Examples of the polymerization inhibitor include phenol-based, sulfur-based, phosphorus-based, hindered amine-based, nitroso-based, and nitroxyl radical-based inhibitors. One type of polymerization inhibitor may be used alone, or multiple types may be used in combination. Among these, phenol-based, hindered amine-based, nitroso-based, and nitroxyl radical-based inhibitors are preferred in the present invention.

[0069] Examples of the phenolic polymerization inhibitor 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-3,5-di-t-butylanilino)-1,3,5-triazine, 2,4-bis[(octylthio)methyl]-o ...butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyanisole, butylated hydroxyani Monophenols such as resol, 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 Bisphenols such as calcium ethyl-4-hydroxybenzylsulfonate, 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,Examples of the phenolic compound include, but are not limited to, polymeric phenols such as 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.

[0070] Examples of the sulfur-based polymerization inhibitor include, but are not limited to, dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, and distearyl-3,3'-thiodipropionate.

[0071] Examples of the phosphorus-based polymerization inhibitor 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 bi(2,4-di-t-butylphenyl) phosphite, cyclic neopentane tetrayl bi(2,4-di-t-butyl-4-methylphenyl) phosphite, bis[2-t 10-(3,5-di-t-butyl-4-hydroxybenzyl)-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, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and the like, but are not limited to these.

[0072] Examples of the hindered amine polymerization inhibitor include, but are not limited to, ADK STAB LA-40MP, ADK STAB LA-40Si, ADK STAB LA-402AF, ADK STAB LA-87, DECASTAB LA-82, DECASTAB 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, ADK STAB LA-52, Chimassorb 2020FDL, Chimassorb 944FDL, Chimassorb 944LD, Tinuvin 622SF, Tinuvin PA144, Tinuvin 765, Tinuvin 770DF, Tinuvin XT55FB, Tinuvin 111FDL, Tinuvin 783FDL, and Tinuvin 791FB.

[0073] Examples of the nitroso-based polymerization inhibitor include, but are not limited to, p-nitrosophenol, N-nitrosodiphenylamine, ammonium salt of N-nitrosophenylhydroxyamine, (cupferron), etc. Among these, the ammonium salt of N-nitrosophenylhydroxyamine (cupferron) is preferred.

[0074] Examples of the nitroxyl radical polymerization inhibitor include 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, but are not limited to these.

[0075] [Flame retardant] The curable resin composition of the present invention may contain a flame retardant. Examples of the flame retardant include halogen-based flame retardants, inorganic flame retardants (antimony compounds, metal hydroxides, nitrogen compounds, boron compounds, etc.), and phosphorus-based flame retardants. From the viewpoint of achieving halogen-free flame retardancy, phosphorus-based flame retardants are preferred. The phosphorus-based flame retardant may be either a reactive type or an additive type. Specific examples include phosphate esters such as trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylylene phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixylylene phosphate, 1,3-phenylenebis(dixylylene phosphate), 1,4-phenylenebis(dixylylene phosphate), and 4,4'-biphenyl(dixylylene phosphate); phosphanes such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 10(2,5-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. These may be used alone or in combination. Of the above-mentioned exemplified substances, phosphate esters, phosphanes, and phosphorus-containing epoxy compounds are preferred, and 1,3-phenylenebis(dixylilenyl phosphate), 1,4-phenylenebis(dixylilenyl phosphate), 4,4'-biphenyl(dixylilenyl phosphate), and phosphorus-containing epoxy compounds are particularly preferred. The content of the flame retardant is preferably in the range of 0.1 to 0.6 parts by mass, assuming that the total of the maleimide compound (A) and the amine compound (B) is 100 parts by mass. If the content is less than 0.1 part by mass, the flame retardancy may be insufficient, while if the content is more than 0.6 part by mass, the low moisture absorption and low dielectric properties of the cured product may be adversely affected.

[0076] [Light stabilizer] The curable resin composition of the present invention may contain a light stabilizer, and as the light stabilizer, a hindered amine light stabilizer, particularly HALS, etc., is preferred. Examples of HALS include reaction products 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, reaction products 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}], 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, bis(1,2,2,6,6-pentamethyl-4-piperidyl)2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate, etc., but are not limited thereto. These may be used alone or in combination.

[0077] The content of the light stabilizer is preferably in the range of 0.001 to 0.1 parts by mass, assuming that the total of the maleimide compound (A) and the amine compound (B) is 100 parts by mass. If the content is less than 0.001 part by mass, the light stabilizing effect may be insufficient, and if the content is more than 0.1 part by mass, the low moisture absorption and low dielectric properties of the cured product may be adversely affected.

[0078] [Binder resin] The curable resin composition of the present invention may contain a binder resin. 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, and silicone resins. These may be used alone or in combination.

[0079] The amount of binder resin to be added 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 mass, and more preferably 0.05 to 20 parts by mass, based on 100 parts by mass of the total of the maleimide compound (A) and the amine compound (B).

[0080] [Additives] The curable resin composition of the present invention may contain additives, such as modified acrylonitrile copolymers, polyethylene, fluororesins, silicone gels, silicone oils, surface treatment agents for fillers such as silane coupling agents, release agents, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

[0081] The amount of the additive to be added is preferably 1 part by mass or less, more preferably 0.7 parts by mass or less, per 100 parts by mass of the total of the maleimide compound (A) and the amine compound (B).

[0082] The curable resin composition of this embodiment may further contain maleimide compounds other than the maleimide compound (A), epoxy resins, active ester compounds, phenolic resins, polyphenylene ether compounds, amine resins other than the amine compound (B), compounds having an ethylenically unsaturated bond, isocyanate resins, polyamide resins, cyanate ester resins, polyimide resins, polybutadiene and modified products thereof, polystyrene and modified products thereof, polyethylene and modified products thereof, benzoxazine compounds, etc., which may be used alone or in combination. Among these compounds, maleimide compounds other than the maleimide compound (A), 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 are preferred in terms of the balance of heat resistance, adhesion, and dielectric properties. The inclusion of these compounds 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. Unless otherwise specified, the amount of the above compounds used is preferably 10 times by mass or less, more preferably 5 times by mass or less, and particularly preferably 3 times by mass or less, relative to the total amount of the maleimide compound (A) and the amine compound (B). The lower limit is preferably 0.1 times by mass or more, more preferably 0.25 times by mass or more, and even more preferably 0.5 times by mass or more. By keeping the amount within the above range, it is possible to enhance the effects of each compound added while taking advantage of the properties of the maleimide compound and the amine compound. The following examples of these components can be used.

[0083] [Epoxy resin] Preferred examples of epoxy resins include, but are not limited to, the following. The epoxy resin may be liquid or solid, and may be used alone or in combination.

[0084] Examples of liquid epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexanedimethanol type epoxy resins, glycidyl amine type epoxy resins, and epoxy resins having a butadiene structure. Specific examples include "RE310S" and "RE410S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol A type epoxy resin), "RE303S", "RE304S", "RE403S", and "RE404S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy resin), "HP4032", "HP4032D", and "HP4032SS" (all manufactured by DIC Corporation, naphthalene type epoxy resin), "828US", "jER828EL", "825", and "828EL" (all manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin), "jE807", and "1750" (all manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin), and "jER152" (manufactured by Mitsubishi Chemical Corporation, phenol Novolac epoxy resin), "630", "630LSD" (all manufactured by Mitsubishi Chemical Corporation, glycidylamine epoxy resin), "ZX1059" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin), "EX-721" (manufactured by Nagase ChemteX Corporation, glycidyl ester epoxy resin), "Celloxide 2021P" (manufactured by Daicel Corporation, alicyclic epoxy resin having an ester skeleton), "PB-3600" (manufactured by Daicel Corporation, epoxy resin having a butadiene structure), "ZX1658", "ZX1658GS" (all manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., liquid 1,4-glycidylcyclohexane epoxy resin), etc. These may be used alone or in combination of two or more.

[0085] Preferred examples of solid epoxy resins include bixylenol-type epoxy resins, naphthalene-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol AF-type epoxy resins, and tetraphenylethane-type epoxy resins, and examples of such solid epoxy resins include naphthol-type epoxy resins, bisphenol AF-type epoxy resins, naphthalene-type epoxy resins, and biphenyl-type epoxy resins.Specific examples include "HP4032H" (manufactured by DIC Corporation, naphthalene-type epoxy resin), "HP-4700", "HP-4710" (all manufactured by DIC Corporation, naphthalene-type tetrafunctional epoxy resin), "N-690" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), "N-695" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), "HP-7200" (manufactured by DIC Corporation, dicyclopentadiene-type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (all manufactured by DIC Corporation, dicyclopentadiene-type epoxy resin). epoxy resin), "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP-6000" (all manufactured by DIC Corporation, naphthylene ether type epoxy resin), "EPPN-502H" (manufactured by Nippon Kayaku Co., Ltd., trisphenol type epoxy resin), "NC-7000L", "NC-7300" (all manufactured by Nippon Kayaku Co., Ltd., naphthol-cresol novolac type epoxy resin), "NC-3000H", "NC-3000", "NC-3000L", "NC-3100" (all manufactured by Nippon Kayaku Co., Ltd., biphenyl ether type epoxy resin), raryl-type epoxy resin), "XD-1000-2L", "XD-1000-L", "XD-1000-H", "XD-1000-H" (all manufactured by Nippon Kayaku Co., Ltd., dicyclopentadiene-type epoxy resin), "ESN475V" (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., naphthol-type epoxy resin), "ESN485" (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., naphthol novolac-type epoxy resin), "YX-4000H", "YX-4000", "YL6121" (all manufactured by Mitsubishi Chemical Corporation, biphenyl-type epoxy resin), "YX-4000HK" (manufactured by Mitsubishi Chemical Corporation, biphenyl-type epoxy resin) Examples of epoxy resins that can be used include "YX-8800" (manufactured by Mitsubishi Chemical Corporation, anthracene-type epoxy resin), "PG-100" and "CG-500" (manufactured by Osaka Gas Chemicals Co., Ltd., fluorene-based epoxy resin), "YL-7760" (manufactured by Mitsubishi Chemical Corporation, bisphenol AF-type epoxy resin), "YL-7800" (manufactured by Mitsubishi Chemical Corporation, fluorene-type epoxy resin), "jER1010" (manufactured by Mitsubishi Chemical Corporation, solid bisphenol A-type epoxy resin), and "jER1031S" (manufactured by Mitsubishi Chemical Corporation, tetraphenylethane-type epoxy resin).These may be used alone or in combination of two or more.

[0086] [Active ester compounds] An active ester compound refers to a compound containing at least one ester bond in its structure, with an aliphatic chain, an aliphatic ring, or an aromatic ring bonded to both sides of the ester bond. Examples of active ester compounds include phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, which have two or more highly reactive ester groups per molecule. These compounds are obtained by a condensation reaction between at least one of a carboxylic acid compound, an acid chloride, or a thiocarboxylic acid compound and at least one of a hydroxy compound or a thiol compound. From the viewpoint of improving heat resistance, active ester compounds are preferably obtained from a carboxylic acid compound or an acid chloride and a hydroxy compound, with phenol compounds or naphthol compounds being preferred as the hydroxy compound. Active ester compounds may be used singly or in combination of two or more.

[0087] 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.

[0088] Examples of the acid chloride include acetyl chloride, acrylic acid chloride, methacrylic acid chloride, malonyl chloride, succinic acid dichloride, diglycolyl chloride, glutaric acid dichloride, suberic acid dichloride, sebacic acid dichloride, adipic acid dichloride, dodecandioyl dichloride, azelaic acid chloride, 2,5-furandicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, and 4,4'-azodibenzoyl dichloride.

[0089] Examples of the phenol compound and naphthol compound 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, phloroglucinol, benzenetriol, dicyclopentadiene-type diphenol compounds, phenol novolak, and the phenolic resins described below. Here, the term "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing one dicyclopentadiene molecule with two phenol molecules.

[0090] Preferred specific examples of the active ester compound include active ester compounds containing a dicyclopentadiene-type diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated product of phenol novolac, active ester compounds containing a benzoylated product of phenol novolac, the compound described in Example 2 of WO 2020 / 095829, and the compounds disclosed in WO 2020 / 059625. Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene-type diphenol structure are more preferred. The dicyclopentadiene-type diphenol structure refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

[0091] Commercially available active ester compounds include, for example, "EXB9451," "EXB9460," "EXB9460S," "HPC-8000-65T," "HPC-8000H-65TM," "EXB-8000L-65TM," and "EXB-8150-65T" (manufactured by DIC Corporation) as active ester compounds containing a dicyclopentadiene-type diphenol structure, "EXB9416-70BK" (manufactured by DIC Corporation) as an active ester compound containing a naphthalene structure, and "EXB9416-70BK" (manufactured by DIC Corporation) as an active ester compound containing a phenol novolak structure. Examples of active ester compounds containing benzoylated phenol novolac include "DC808" (manufactured by Mitsubishi Chemical Corporation), active ester compounds containing benzoylated phenol novolac include "YLH1026," "YLH1030," and "YLH1048" (manufactured by Mitsubishi Chemical Corporation), an active ester curing agent that is an acetylated phenol novolac is "DC808" (manufactured by Mitsubishi Chemical Corporation), and an active ester curing agent containing a phosphorus atom is "EXB-9050L-62M" (manufactured by DIC Corporation).

[0092] Regarding the compounding ratio of the active ester compound and the epoxy resin, the ratio (α / β) of the active ester equivalent (α) to the epoxy equivalent (β) is preferably 0.5 to 1.5, more preferably 0.8 to 1.2, and even more preferably 0.90 to 1.10. If the ratio is outside this range, excess epoxy groups or active ester groups may remain in the system, which may deteriorate the properties in high-temperature storage tests (e.g., 150°C, 1000 hours) or long-term reliability tests under high-temperature and high-humidity conditions (e.g., temperature: 85°C, humidity: 85%).

[0093] [Phenol resin] A phenolic resin is a compound having two or more phenolic hydroxyl groups in the molecule. Examples of phenolic resins include, but are not limited to, reaction products of phenols and aldehydes, reaction products of phenols and diene compounds, reaction products of phenols and ketones, reaction products of phenols and substituted biphenyls, reaction products of phenols and substituted phenyls, and reaction products of bisphenols and aldehydes. These may be used alone or in combination. Specific examples of the above raw materials are given below, but are not limited to these. <Phenols> Phenol, alkyl-substituted phenol, aromatic-substituted phenol, hydroquinone, resorcinol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc. <Aldehydes> Formaldehyde, acetaldehyde, alkyl aldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural, and the like. <Diene compounds> Dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, and the like. <Ketones> Acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, fluorenone, etc. <Substituted biphenyls> 4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, 4,4'-bis(hydroxymethyl)-1,1'-biphenyl and the like. <Substituted phenyls> 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene and the like.

[0094] [Polyphenylene ether compounds] From the viewpoints of heat resistance and electrical properties, the polyphenylene ether compound is preferably a polyphenylene ether compound having an ethylenically unsaturated bond, and more preferably a polyphenylene ether compound having an acrylic group, a methacrylic group, or a styrene structure. Commercially available products include SA-9000-111 (manufactured by SABIC, a polyphenylene ether compound having a methacrylic group), OPE-2St 1200 (manufactured by Mitsubishi Gas Chemical Company, Inc., a polyphenylene ether compound having a styrene structure), and OPE-2St 2200 (manufactured by Mitsubishi Gas Chemical Company, Inc., 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 low dielectric properties while exhibiting excellent heat resistance, moldability, etc. The number average molecular weight here can be specifically measured using gel permeation chromatography, etc.

[0095] 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 bond, such as methacryl chloride, acrylic chloride, or chloromethylstyrene, to impart radical polymerizability. The polyphenylene ether compound obtained by the 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. The polyphenylene ether compound obtained by the redistribution reaction thus has hydroxyl groups derived from the phenolic compound 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 bond. Furthermore, the polyphenylene ether compound obtained by the polymerization reaction is preferred because it exhibits excellent flowability.

[0096] 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.

[0097] The content of the polyphenylene ether compound is not particularly limited, but is preferably 5 to 1,000 parts by mass, and more preferably 10 to 750 parts by mass, relative to 100 parts by mass of the total of the maleimide compound (A) and the amine compound (B). A content of the polyphenylene ether compound within the above range is preferable in that it not only has excellent heat resistance, etc., but also allows a cured product to be obtained that fully exhibits the excellent dielectric properties of the polyphenylene ether compound.

[0098] [Amine resins other than amine compound (B)] The amine resin other than the amine compound (B) is a compound having two or more amino groups in the molecule, other than the amine compound (B). Examples of the amine resin include diaminodiphenylmethane, diaminodiphenylsulfone, isophoronediamine, naphthalenediamine, aniline novolak (a reaction product of aniline and formalin), N-methylaniline novolak (a reaction product of N-methylaniline and formalin), orthoethylaniline novolak (a reaction product of orthoethylaniline and formalin), a reaction product of 2-methylaniline and formalin, a reaction product of 2,6-diisopropylaniline and formalin, a reaction product of 2,6-diethylaniline and formalin, a reaction product of 2-ethyl-6-ethylaniline and formalin, a reaction product of 2,6-dimethylaniline and formalin, and a reaction product obtained by the reaction of aniline and xylylene chloride. Examples of suitable aniline resins include, but are not limited to, aniline resins disclosed in Japanese Patent No. 6429862, reaction products of aniline and substituted biphenyls (such as 4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl), reaction products of aniline and substituted phenyls (such as 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene), 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, reaction products of aniline and diisopropenylbenzene, and dimer diamine. These may be used singly or in combination.

[0099] [Compounds containing ethylenically unsaturated bonds] A compound containing an ethylenically unsaturated bond is a compound having one or more ethylenically unsaturated bonds in the molecule that are polymerizable by heat or light, regardless of whether a polymerization initiator is used. The ethylenically unsaturated bond is preferably a styryl group or a methacrylic group, with a styryl group being particularly preferred. The ethylenically unsaturated bond equivalent is preferably 50 g / eq. to 3000 g / eq., more preferably 75 g / eq. to 2500 g / eq., even more preferably 90 g / eq. to 2000 g / eq., and particularly preferably 100 g / eq. to 1500 g / eq. Examples of the compound containing an ethylenically unsaturated bond include a reaction product of the above-mentioned phenol resin with an ethylenically unsaturated bond-containing halogen-based compound (chloromethylstyrene, allyl chloride, methallyl chloride, acrylic acid chloride, methacrylic acid chloride, etc.), a reaction product of an ethylenically unsaturated bond-containing phenol (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) with a halogen-based compound (1,4-bis(chloromethyl)benzene), and a reaction product of an ethylenically unsaturated bond-containing phenol (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) with a halogen-based compound (1,4-bis(chloromethyl)benzene). reaction products of epoxy resins or alcohols with (meth)acrylic acids (acrylic acid, methacrylic acid, etc.) and their acid-modified products; poly(arylene ether) polymers (HC-G0037, HC-G0024, HC-G0030, HC-G0038, all manufactured by JSR Corporation. These are pyridazine, pyrimidine, or (It may contain a monomer unit containing a pyrazine group.) Reaction products of fluorenes or indenes with halogen-based compounds containing ethylenically unsaturated bonds (chloromethylstyrene, allyl chloride, methallyl chloride, acrylic acid chloride, methacrylic acid chloride, etc.), compounds described in Japanese Patent No. 6951829, copolymers containing divinylbenzene as a constituent unit (ODV-XET(X3), ODV-XET(X4), ODV-XET(X5), all manufactured by Nippon Steel Chemical & Material Co., Ltd.), styrene, vinyltoluene, methyl methacrylate, methyl styrene ... Examples of suitable vinyl olefins include, but are not limited to, vinylene, ethylvinylbenzene, vinylnaphthalene, vinylbiphenyl, vinylfluorene, divinylbenzene, divinylnaphthalene, divinylbiphenyl, divinylfluorene, BVPM (bis(vinylphenyl)methane), BVPE (bis(vinylphenyl)ethane), BVPH (bis(vinylphenyl)hexane), trivinylcyclohexane, and thermosetting cycloolefin copolymers (Gigafreak manufactured by Mitsui Chemicals, Inc., and TU-01A manufactured by Zeon Corporation). These may be used alone or in combination.

[0100] [Cyanate ester resin] Cyanate ester resins are cyanate ester compounds obtained by reacting phenolic resins with cyanogen halides. Specific examples include, but are not limited to, dicyanatobenzene, tricyanatobenzene, dicyanatonaphthalene, dicyanatobiphenyl, 2,2'-bis(4-cyanatophenyl)propane, 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. These compounds may be used alone or in combination. Furthermore, the cyanate ester compound, the synthesis method of which is described in JP-A-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 optionally contain a catalyst such as zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octoate, tin octoate, lead acetylacetonate, or dibutyltin maleate to trimerize the cyanate group to form a sym-triazine ring.

[0101] The catalyst is preferably used in an amount of 0.0001 to 0.10 parts by mass, and more preferably 0.00015 to 0.0015 parts by mass, per 100 parts by mass of the curable resin composition.

[0102] [Isocyanate resin] An isocyanate resin is a compound that has two or more isocyanate groups in its molecule. Examples of the isocyanate resin include, but are not limited to, 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 one or more biuret forms of isocyanate monomers or isocyanate forms obtained by trimerizing the above-mentioned diisocyanate compounds; and polyisocyanates obtained by a urethanization reaction between the above-mentioned isocyanate compounds and polyol compounds. These may be used alone or in combination.

[0103] [Polyamide resin] Examples of polyamide resins include reaction products of one or more of diamines, diisocyanates, and oxazolines with dicarboxylic acids, reaction products of diamines with acid chlorides, and ring-opening polymers of lactam compounds. These may be used alone or in combination. Specific examples of the above raw materials are given below, but are not limited to these. <Diamine> Ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-diaminopentane, 2-methyl 1,8-diaminooctane, dimer diamine, cyclohexanediamine, bis-(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, xylylenediamine, norbornanediamine, isophoronediamine, bisaminomethyltricyclodecane, phenylenediamine, diethyltoluenediamine, naphthalenediamine, diaminodiphenylmethane, bis(4-amino-3,5-dimethylphenyl)methane, bis(4-amino-3,5-diethylphenyl)methane , 4,4'-methylenebis-o-toluidine, 4,4'-methylenebis-o-ethylaniline, 4,4'-methylenebis-2-ethyl-6-methylaniline, 4,4'-methylenebis-2,6-diisopropylaniline, 4,4-ethylenedianiline, diaminodiphenyl sulfone, diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-amino 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, 9,9-bis(4-aminophenyl)fluorene, 2,7-diaminofluorene, aminobenzylamine, diaminobenzophenone, and the like. <Diisocyanate> Benzene diisocyanate, toluene diisocyanate, 1,3-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)cyclohexane, bis(4-isocyanatophenyl)methane, isophorone diisocyanate, 1,3-bis(2-isocyanato-2-propyl)benzene, 2,2-bis(4-isocyanatophenyl)hexafluoropropane, dicyclohexylmethane-4,4'-diisocyanate, and the like. <Dicarboxylic acid> Oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 5-hydroxyisophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, cyclohexanedicarboxylic acid, biphenyldicarboxylic acid, naphthalenedicarboxylic acid, benzophenonedicarboxylic acid, furandicarboxylic acid, 4,4'-dicarboxydiphenyl ether, 4,4'-dicarboxydiphenyl sulfide, etc. <Acid chloride> Acetyl chloride, acrylic acid chloride, methacrylic acid chloride, malonyl chloride, succinic acid dichloride, diglycolyl chloride, glutaric acid dichloride, suberic acid dichloride, sebacic acid dichloride, adipic acid dichloride, dodecandioyl dichloride, azelaic acid chloride, 2,5-furandicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, 4,4'-azodibenzoyl dichloride and the like. <Lactam> ε-caprolactam, ω-undecanelactam, ω-laurolactam, and the like.

[0104] [Polyimide resin] Examples of polyimide resins include, but are not limited to, reaction products of the above diamines with the following tetracarboxylic dianhydrides. These may be used alone or in combination. <Tetracarboxylic acid dianhydride> 4,4'-(Hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2dicarboxylic anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic 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, sulfonyl-4,4'-diphthalic acid Dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]meth 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 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, 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-oxabicyclo[3,2 ,1]Octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, ethylene glycol-bis-(3,4-dicarboxylic acid anhydride phenyl) ether, 4,4'-biphenyl bis(trimellitic acid monoester acid anhydride), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, etc.,

[0105] [Maleimide Compounds Other Than Maleimide Compound (A)] The curable resin composition of the present embodiment may contain a maleimide compound other than the maleimide compound (A). Specifically, it may contain an aliphatic maleimide resin or an aromatic maleimide resin having a maleimide equivalent of less than 250 g / eq. or more than 1000 g / eq., and examples thereof include 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), Xyloc-type maleimide resin (anilix), Maleimide, manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenylaralkyl-type maleimide resin (solidified by distilling off the solvent under reduced pressure from a resin solution containing the maleimide resin (M2) described in Example 4 of JP 2009-001783 A), bisaminocumylbenzene-type maleimide (maleimide resin described in WO 2020 / 054601 A), maleimide resins having an indane structure described in Japanese Patent No. 6629692 or WO 2020 / 217679, MATERIAL STAGE Vol. 18, No. 12 2019 "Continued Story of Epoxy Resin CAS Numbers - Hardener CAS Number Memorandum No. 31 Bismaleimide (1)" and MATERIAL STAGE Vol. 19, No. 2 2019 "Continued Story of Epoxy Resin CAS Numbers - Hardener CAS Number Memorandum No. 32" Examples of the maleimide resin include, but are not limited to, the maleimide resins described in "Bismaleimide (2)." These may be used alone or in combination.

[0106] [Polybutadiene and its modified products] Polybutadiene and its modified products are polybutadiene or compounds having a structure derived from polybutadiene in the molecule. The unsaturated bonds in the polybutadiene-derived structure may be partially or entirely converted to single bonds by hydrogenation. Examples of polybutadiene and its modified products include, but are not limited to, polybutadiene, hydroxyl-terminated polybutadiene, (meth)acrylate-terminated polybutadiene, carboxylic acid-terminated polybutadiene, amine-terminated polybutadiene, and styrene-butadiene rubber. These may be used alone or in combination. Among these, polybutadiene or styrene-butadiene rubber is preferred from the viewpoint of dielectric properties. Examples of styrene-butadiene rubber (SBR) include RICON-100, RICON-181, and RICON-184 (all manufactured by Cray Valley Corporation), and 1,2-SBS (manufactured by Nippon Soda Co., Ltd.). Examples of polybutadiene include B-1000, B-2000, and B-3000 (all manufactured by Nippon Soda Co., Ltd.). The molecular weight of polybutadiene and styrene-butadiene rubber is preferably a weight-average molecular weight of 500 to 10,000, more preferably 750 to 7,500, and even more preferably 1,000 to 5,000. Below the lower limit of the above range, the amount of evaporation is high, making it difficult to adjust the solids content during prepreg production, while above the upper limit of the above range, compatibility with other curable resins deteriorates. Generally, in the case of compounds containing heteroatoms such as oxygen or nitrogen, such as bismaleimides and polymaleimides, it is difficult to ensure compatibility with low-polarity compounds, such as compounds composed mainly of hydrocarbons or compounds composed only of hydrocarbons, due to their polarity. On the other hand, the maleimide compounds of the present invention, which do not have a skeleton design that actively incorporates heteroatoms such as oxygen or nitrogen, exhibit excellent compatibility with materials having low polarity and low dielectric properties, as well as compounds composed only of hydrocarbons.

[0107] [Polystyrene and its modified products] Polystyrene and its modified products are polystyrene or compounds having a structure derived from polystyrene in the molecule. Examples of polystyrene and modified products thereof include polystyrene, styrene-2-isopropenyl-2-oxazoline copolymer (Epocross RPS-1005, RP-61, both manufactured by Nippon Shokubai Co., Ltd.), SEP (styrene-ethylene-propylene copolymer: Septon 1020, manufactured by Kuraray Co., Ltd.), SEPS (styrene-ethylene-propylene-styrene copolymer: Septon 2002, Septon 2004F, Septon 2005, Septon 2006, Septon 2063, Septon 2104, all manufactured by Kuraray Co., Ltd.), SEEPS (styrene-ethylene / ethylene-propylene-styrene block copolymer: Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099, all manufactured by Kuraray Co., Ltd.), SEBS (styrene-ethylene-butylene-styrene copolymer: Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099, all manufactured by Kuraray Co., Ltd.), Examples of suitable block copolymers include Septon 8004, Septon 8006, and Septon 8007L (all manufactured by Kuraray Co., Ltd.), SEEPS-OH (a styrene-ethylene / ethylene-propylene-styrene block copolymer having a terminal hydroxyl group: Septon HG252, manufactured by Kuraray Co., Ltd.), SIS (styrene-isoprene-styrene block copolymer: Septon 5125 and Septon 5127, both manufactured by Kuraray Co., Ltd.), hydrogenated SIS (hydrogenated styrene-isoprene-styrene block copolymer: Hybrar 7125F and Hybrar 7311F, both manufactured by Kuraray Co., Ltd.), and SIBS (styrene-isobutylene-styrene block copolymer: SIBSTAR 073T, SIBSTAR 102T, and SIBSTAR 103T (all manufactured by Kaneka Corporation), and Septon V9827 (manufactured by Kuraray Co., Ltd.)), but are not limited to these. These may be used alone or in combination. Polystyrene and its modified products are preferably free of unsaturated bonds, since they have higher heat resistance and are less susceptible to oxidative degradation. The weight-average molecular weight of polystyrene and its modified products is not particularly limited as long as it is 10,000 or more, but if it is too large, compatibility with not only polyphenylene ether compounds but also low-molecular-weight components with a weight-average molecular weight of about 50 to 1,000 and oligomer components with a weight-average molecular weight of about 1,000 to 5,000 deteriorates, making it difficult to ensure mixing and solvent stability. Therefore, the weight-average molecular weight is preferably about 10,000 to 300,000.

[0108] [Polyethylene and its modified products] Polyethylene and its modified products are polyethylene or compounds having a polyethylene-derived structure in the molecule. Examples of polyethylene and its modified products include, but are not limited to, ethylene-propylene copolymers, ethylene-styrene copolymers, ethylene-propylene-ethylidene norbornene copolymers (EBT: K-8370EM, K-9330M, etc., manufactured by Mitsui Chemicals, Inc.), ethylene-propylene-vinyl norbornene copolymers (VNB-EPT: PX-006M, PX-008M, PX-009M, etc., manufactured by Mitsui Chemicals, Inc.), ethylene-vinyl alcohol copolymers, and ethylene-vinyl acetate copolymers. From the viewpoint of improving heat resistance, it is preferable to use ethylene-propylene-ethylidene norbornene copolymers or ethylene-propylene-vinyl norbornene copolymers containing a crosslinkable structure. These may be used alone or in combination. There are no particular restrictions on the weight-average molecular weight of polyethylene and modified polyethylenes thereof as long as it is 10,000 or more. However, if it is too large, compatibility with not only polyphenylene ether compounds but also low-molecular-weight components with a weight-average molecular weight of about 50 to 1,000 and oligomer components with a weight-average molecular weight of about 1,000 to 5,000 deteriorates, making it difficult to ensure mixing and solvent stability. Therefore, it is preferably about 10,000 to 300,000.

[0109] [Benzoxazine compounds] As the benzoxazine compound, any known compound having two or more dihydrobenzoxazine rings in one molecule can be used. Examples include, but are not limited to, bisphenol A benzoxazine BA-BXZ (manufactured by Konishi Chemical Co., Ltd.), bisphenol F benzoxazine BF-BXZ (manufactured by Konishi Chemical Co., Ltd.), bisphenol S benzoxazine BS-BXZ (manufactured by Konishi Chemical Co., Ltd.), and phenolphthalein benzoxazine. These benzoxazine compounds can be used alone or in combination of two or more.

[0110] The curable resin composition of the present invention can be obtained by preparing the above-mentioned components in a predetermined ratio, pre-curing the composition at 130 to 180°C for 30 to 500 seconds, and then post-curing the composition at 150 to 200°C for 2 to 15 hours, thereby allowing the curing reaction to proceed sufficiently and producing the cured product of the present invention. Alternatively, the components of the curable resin composition can be uniformly dispersed or dissolved in a solvent or the like, and then cured after removing the solvent.

[0111] The method for preparing the curable resin composition of the present invention is not particularly limited, and the components may be simply mixed uniformly or may be prepolymerized. The mixing or prepolymerization of the components may be carried out using, for example, an extruder, kneader, or roll in the absence of a solvent, or using a reaction vessel equipped with a stirrer in the presence of a solvent.

[0112] To achieve uniform mixing, the components 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 curable resin composition. The resulting curable resin composition can be pulverized and then molded into cylindrical tablets using a molding machine such as a tablet machine, or into granular powder or powder-like molded products. Alternatively, these compositions can be melted on a surface support and molded into a sheet with a thickness of 0.05 mm to 10 mm to obtain a molded curable resin composition. The resulting molded product is non-sticky at 0 to 20°C, and exhibits little loss of 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.

[0113] The curable resin composition of the present invention can also be converted into a varnish-like composition (hereinafter simply referred to as varnish) by adding an organic solvent. The curable resin composition of the present invention 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 the present invention. The solvent used in this process is in an amount of 10 to 70 parts by mass, preferably 15 to 70 parts by mass, based on the mixture of the curable resin composition of the present invention and the solvent. Furthermore, if the composition is in liquid form, a cured curable resin containing carbon fiber can also be obtained directly, for example, by the RTM method.

[0114] The curable resin composition of the present invention can also be used as a modifier for film-type 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 the present invention as a varnish onto a release film, removing the solvent under heating, and then performing B-stage formation. This sheet-type adhesive can be used as an interlayer insulating layer in a multilayer substrate, etc.

[0115] The curable resin composition of the present invention can also be used to obtain a prepreg by heating and melting it to reduce its viscosity and impregnating it into reinforcing fibers such as glass fibers, carbon fibers, polyester fibers, polyamide fibers, and alumina fibers. Specific examples include, but are not limited to, glass fibers such as E-glass cloth, D-glass cloth, S-glass cloth, Q-glass cloth, spherical glass cloth, NE-glass cloth, and T-glass cloth; inorganic fibers other than glass; and organic fibers such as polyparaphenylene terephthalamide (Kevlar®, manufactured by DuPont), wholly aromatic polyamide, polyester, polyparaphenylene benzoxazole, polyimide, and carbon fiber. The shape of the substrate is not particularly limited, but examples include woven fabric, nonwoven fabric, roving, and chopped strand mat. Known weaving methods for woven fabrics include plain weave, saddle weave, and twill weave, and these known methods can be appropriately selected 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.

[0116] A laminate can also be manufactured using the prepreg. The laminate is not particularly limited as long as it includes one or more prepregs, and may also include any other layers. The method for manufacturing the laminate can be any generally known method, and is not particularly limited. For example, when molding a metal foil-clad laminate, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, an autoclave molding machine, or the like can be used. The prepregs are laminated together and then heated and pressure molded 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 if the pressure is too high, it becomes difficult to adjust the resin solid content of the laminate, resulting in unstable quality. If the pressure is too low, air bubbles will form and adhesion between the laminate layers will be poor. Therefore, a pressure of 2.0 to 5.0 MPa is preferred, and 2.5 to 4.0 MPa is more preferred. The laminate of this embodiment, having a layer made of metal foil, can be suitably used 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.

[0117] The curable resin composition of the present invention can also be made into a resin sheet. A method for obtaining a resin sheet from the curable resin composition of the present invention includes, for example, applying the curable resin composition onto a support film (support), followed by drying to form a resin composition layer on the support film. When the curable resin composition of the present invention is used for a resin sheet, it is essential that the film softens under the lamination temperature conditions (70°C to 140°C) in the vacuum lamination method, and exhibits fluidity (resin flow) that allows resin to fill via holes or through holes present in the circuit board simultaneously with lamination of the circuit board. It is preferable to blend the above-mentioned components so as to exhibit such properties. The resin sheet or circuit board ( In the case of laminates (e.g., copper-clad laminates), uniform appearance is required to ensure consistent performance at any given location without causing phenomena such as phase separation, which can result in locally varying characteristic values.

[0118] Here, the diameter of the through-holes in the circuit board is 0.1 to 0.5 mm, and the depth is 0.1 to 1.2 mm, and it is preferable to make it possible to fill the resin within this range. When laminating both sides of the circuit board, it is desirable to fill about half of the through-holes.

[0119] A specific method for producing the resin sheet includes preparing a resin composition varnished by blending an organic solvent, applying the varnished resin composition to the surface of a support film (Y), and then drying the organic solvent by heating or blowing hot air, etc., to form a resin composition layer (X).

[0120] The organic solvent used here is preferably, for example, a ketone such as acetone, methyl ethyl ketone, or cyclohexanone; an acetate ester such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, or carbitol acetate; a carbitol such as cellosolve or butyl carbitol; an aromatic hydrocarbon such as toluene or xylene; dimethylformamide, dimethylacetamide, or N-methylpyrrolidone; and it is preferably used in a proportion such that the nonvolatile content is 30 to 60% by mass.

[0121] The thickness of the resin composition layer (X) to be formed must be equal to or greater than the thickness of the conductor layer. Since the thickness of the conductor layer of the circuit board is in the range of 5 to 70 μm, the thickness of the resin composition layer (X) is preferably 10 to 100 μm. The resin composition layer (X) in the present invention may be protected with a protective film, which will be described later. Protection with a protective film can prevent the adhesion of dust and the like to the surface of the resin composition layer and scratches.

[0122] Examples of the support film and protective film include polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate; polycarbonate; polyimide; and release paper and metal foils such as copper foil and aluminum foil. The support film and protective film may be subjected to a mud treatment, corona treatment, or release treatment. The thickness of the support film is not particularly limited, but is generally in the range of 10 to 150 μm, preferably 25 to 50 μm. The thickness of the protective film is preferably 1 to 40 μm.

[0123] The support film (Y) is peeled off after laminating it onto a circuit board or after forming an insulating layer by heat curing. If the support film (Y) is peeled off after the resin composition layer constituting the resin sheet has been heat cured, adhesion of dust and the like during the curing process can be prevented. When peeling off after curing, the support film is previously subjected to a release treatment.

[0124] A multilayer printed circuit board can be produced from the resin sheet obtained as described above. For example, when the resin composition layer (X) is protected by a protective film, the film is peeled off, and then the resin composition layer (X) is laminated onto one or both sides of the circuit board so as to be in direct contact with the circuit board, for example, by a vacuum lamination method. The lamination method may be a batch method or a continuous method using a roll. If necessary, the resin sheet and the circuit board may be heated (preheated) before lamination. The lamination conditions are preferably a pressure bonding temperature (lamination temperature) of 70 to 140°C and a pressure bonding pressure of 1 to 11 kgf / cm. 2 (9.8×10 4 ~107.9×10 4 N / m 2 ), and lamination is preferably carried out under reduced air pressure of 20 mmHg (26.7 hPa) or less.

[0125] The curable resin composition of the present invention can be used to manufacture semiconductor devices, such as DIP (dual in-line package), QFP (quad flat package), BGA (ball grid array), CSP (chip size package), SOP (small outline package), TSOP (thin small outline package), and TQFP (thin quad flat package).

[0126] The curable resin composition and its cured product of the present invention can be used in a wide range of fields. Specifically, they can be used in various applications such as molding materials, adhesives, composite materials, and paints. Because the cured product of the curable resin composition of the present invention exhibits an excellent low coefficient of linear expansion and low dielectric properties, it is suitable for use in electrical and electronic components such as encapsulants for semiconductor devices, encapsulants for liquid crystal display devices, encapsulants for organic EL devices, laminates (printed wiring boards, BGA substrates, build-up substrates, etc.), lightweight, high-strength structural composite materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, 3D printing, etc. [Example]

[0127] The present invention will be described in detail below with reference to examples and comparative examples. In the text, "parts" and "%" represent "parts by mass" and "% by mass", respectively. The softening point and melt viscosity were measured by the following methods. Softening point: Measured according to JIS K-7234 Melt viscosity: Measured by the ICI melt viscosity (150°C) cone-plate method, with units of Pa·s.

[0128] GPC (gel permeation chromatography) analysis Manufacturer:Waters Columns: SHODEX GPC KF-601 (2 columns), KF-602, KF-602.5, KF-603 Flow rate: 0.5ml / min. Column temperature: 40℃ Solvent used: THF (tetrahydrofuran) Detector: RI (differential refractive index detector)

[0129] · HPLC (High Performance Liquid Chromatography) analysis Column: Inertsil ODS-2 Flow rate: 1.0ml / min. Column temperature: 40℃ Solvent used: acetonitrile, water Detector: Photodiode array (225 nm)

[0130] [Synthesis Example 1] Synthesis of aromatic amine resin (A-1) A flask equipped with a thermometer, condenser, Dean-Stark azeotropic distillation trap, and stirrer was charged with 192 parts of aniline, 112 parts of toluene, and 100 parts of 1,3-bis(2-hydroxy-2-propyl)benzene, and 21.5 parts of 35% hydrochloric acid was added dropwise over 10 minutes. The system was heated to 160°C, and the reaction was carried out at the same temperature for 17 hours while distilling off water and toluene. After cooling to 80°C, 124 parts of toluene was added, and 30 parts of 30% aqueous sodium hydroxide solution was added dropwise over 10 minutes. The mixture was then stirred at the same temperature for 2 hours and allowed to stand for 30 minutes. The separated lower aqueous layer was removed, and the reaction solution was repeatedly washed with water until the washings became neutral. Next, the excess aniline and toluene were distilled off from the oil layer using a rotary evaporator under reduced pressure and heating, yielding 158 parts of aromatic amine resin (A-1) represented by formula (2). The aromatic amine resin (A-1) had an amine equivalent of 186.1 g / eq and a softening point of 58.8°C. GPC analysis (RI) showed that the n=1 unit was 62.5 area %. The GPC chart is shown in Figure 1.

[0131] [Synthesis Example 2] Synthesis of maleimide resin (M-1) A flask equipped with a thermometer, condenser, Dean-Stark azeotropic distillation trap, and stirrer was charged with 73.5 parts maleic anhydride, 126 parts toluene, 1.86 parts methanesulfonic acid, and 12.6 parts N-methyl-2-pyrrolidone, and heated to reflux. Next, a resin solution prepared by dissolving 93 parts of aromatic amine resin (A-1) in 55.8 parts toluene was added dropwise over 4 hours while maintaining reflux. During this time, the condensed water and toluene that formed azeotropically under reflux conditions were cooled and separated in the Dean-Stark azeotropic distillation trap. The organic layer, toluene, was then returned to the system, and the water was discharged outside. After the resin solution was added dropwise, the reaction was continued for 10 hours while maintaining reflux and dehydration. After the reaction was completed, the mixture was washed four times to remove methanesulfonic acid and excess maleic anhydride. Water was then removed from the system by azeotroping toluene with water under reduced pressure and heating at 70°C or below. Next, 0.93 parts of methanesulfonic acid was added, and the reaction was carried out under reflux for 4 hours. After the reaction was completed, the mixture was washed four times until the wash water became neutral. Water was then removed from the system by azeotroping toluene with water under reduced pressure and heating at 70°C or below. The toluene was then distilled off under reduced pressure and heating to a resin concentration of approximately 70-80%, after which additional toluene was added to adjust the resin concentration to 60%. This yielded a maleimide solution (V-1) containing the maleimide (M-1) of the present invention. GPC analysis (RI) of the resulting maleimide resin (M-1) revealed that the n=1 isomer was 57.4 area %, the n=2 isomer was 21.3 area %, and the n=3 or more isomer was 21.3 area %. The orientation ratio (ortho-ortho / para-para / ortho-para) in n = 1 isomer was 32.0 area% / 25.4 area% / 42.6 area% by HPLC analysis (225 nm). The softening point was 115.5°C and the viscosity was 6.0 Pa·s. The maleimide equivalent was measured using the method described in JP 2020-187012 A and was found to be 311 g / eq. The GPC chart is shown in Figure 2.

[0132] [Examples 1 to 3, Comparative Examples 1 to 3] [Preparation of cured product] A maleimide compound and an amine compound were weighed out in the proportions (parts by mass) shown in Table 1, and acetone was added to the mixture to give a resin solids content of 70% by mass. A curable resin composition was prepared by heating the varnish in a vacuum dryer at 60°C for 30 minutes and then at 80°C for 30 minutes. The resulting curable resin composition was sandwiched between copper foils and cured at 220°C for 2 hours under a vacuum pressure of 1 MPa. A mark of "O" indicates that a cured product was obtained, and a mark of "X" indicates that a cured product was not obtained. The results are shown in Table 1.

[0133] The cured product obtained above was subjected to measurement of the linear expansion coefficient and the dielectric loss tangent under the following conditions.

[0134] [Linear expansion coefficient measurement] Manufacturer: TA Instruments Equipment: TMAQ400 Measurement mode: Tensile Heating rate: 2℃ / min. Measurement temperature range: 25℃~330℃ A first run was carried out at the heating rate and within the measurement temperature range described above, followed by cooling to 25°C. A second run was then carried out at the same heating rate and within the same measurement temperature range, and the measurement results in the range of 60°C to 90°C were used as the linear expansion coefficient.

[0135] [Dielectric loss tangent measurement] Manufacturer: AET Co., Ltd. Equipment: 10GHz cavity resonator A test piece measuring 2.5 mm in width and 5 cm in length was dried in a dryer at 120°C for 2 hours before measurement.

[0136] [Table 1]

[0137] Maleimide compound: BMI-70 (K.I. Chemicals Co., Ltd., bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, molecular weight 442, number of functional groups 2, maleimide equivalent weight 221 g / eq.) Amine compound: Bisaniline M (Mitsui Fine Chemicals, Inc., 1,3-bis[1-(4-aminophenyl)-1-methylethyl]benzene, molecular weight 345, number of functional groups 2, amine equivalent 173 g / eq.)

[0138] From the results in Table 1, Comparative Examples 1 and 2 were brittle and no cured products could be obtained. In Comparative Example 3, a cured product could be obtained, but the linear expansion coefficient and dielectric loss tangent were insufficient. In Examples 1 to 3, both the linear expansion coefficient and dielectric loss tangent were excellent, and cured products that achieved both properties were obtained.

[0139] <Curing test> [Reference example 1] 20 parts of NC-3000 (Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin), 0.5 parts of MDEA: 4,4'-methylenebis(2,6-diethylaniline) (Tokyo Chemical Industry Co., Ltd., amine compound), 0.5 parts of Bisaniline M (Tokyo Chemical Industry Co., Ltd., amine compound), 1 part of DICY: dicyandiamide (Tokyo Chemical Industry Co., Ltd., amide compound), 0.5 parts of KAYAHARD MCD (Nippon Kayaku Co., Ltd., acid anhydride compound), KAYAHARD 0.5 parts of GPH-65 (Nippon Kayaku Co., Ltd., biphenyl aralkyl type phenol resin), 0.5 parts of Unifiner W-575 (Unitika Ltd., activated ester resin), 0.5 parts of G4-142MHR (Nippon Kayaku Co., Ltd., carboxylic acid compound), 2.5 parts of MIR-3000-70MT (Nippon Kayaku Co., Ltd., maleimide compound), 2.5 parts of MIR-5000-60T (Nippon Kayaku Co., Ltd., maleimide compound), 2.5 parts of MIZ-001 (Nippon Kayaku Co., Ltd., maleimide compound), 0.5 parts of phenylmaleimide (Tokyo Chemical Industry Co., Ltd., maleimide compound), 0.5 parts of CYTESTER TA (Mitsubishi Gas Chemical Co., Ltd., bisphenol A type cyanate resin), OPE-2st 60 parts of 2200 (Mitsubishi Gas Chemical Co., Ltd., polyphenylene ether compound), 3 parts of the compound described in Example 10 of Japanese Patent No. 6951829 (a compound having an ethylenically unsaturated bond), KAYARAD R-684 (manufactured by Nippon Kayaku Co., Ltd., compound having an ethylenically unsaturated bond) 1 part, acenaphthylene (manufactured by Tokyo Chemical Industry Co., Ltd., compound having an ethylenically unsaturated bond) 0.5 parts, 1 part of a polyimide compound obtained by the method described in WO2023 / 013224A1, TAIC: triallyl isocyanurate (manufactured by Mitsubishi Chemical Corporation, allyl compound) 1 part, Septon 2104 (manufactured by Kuraray Co., Ltd., modified polystyrene) 1 part, Pd-type benzoxazine (manufactured by Shikoku Chemical Industry Co., Ltd., benzoxazine compound) 1 part, 2E4MZ: 2-ethyl-4-methylimidazole (manufactured by Shikoku Chemical Industry Co., Ltd., curing accelerator) 0.5 parts, TPP: triphenylphosphine (manufactured by Hokko Chemical Industry Co., Ltd., curing accelerator) 0.5 parts, Octope Zn (manufactured by Hope Pharmaceutical Co., Ltd., curing accelerator) 0.1 parts, San-Aid 0.1 parts of SI-B5 (Sanshin Chemical Co., Ltd., curing accelerator), 1 part of DCP: dicumyl peroxide (Kayaku Nouryon Co., Ltd., polymerization initiator), and 99.9% toluene as a solvent.A cured product was obtained by mixing 2 parts of acrylic acid and 49.6 parts of tetrahydrofuran and heating in a nitrogen atmosphere at 110°C for 10 minutes and then at 220°C for 1 hour.

[0140] [Reference example 2] 50 parts of NC-3000 (Nippon Kayaku Co., Ltd., biphenylaralkyl type epoxy resin), 10 parts of MIZ-001 (Nippon Kayaku Co., Ltd., maleimide compound), 10 parts of MIR-5000-60T (Nippon Kayaku Co., Ltd., maleimide compound), 6 parts of Bisaniline M (Tokyo Chemical Industry Co., Ltd., amine compound), 5 parts of the compound described in Example 10 of Japanese Patent No. 6951829 (Nippon Kayaku Co., Ltd., compound having an ethylenically unsaturated bond), 45 parts of KAYARAD R-684 (Nippon Kayaku Co., Ltd., compound having an ethylenically unsaturated bond), 1 part of Irgacure OXE-04 (BASF, polymerization initiator), Irgacure 290 (BASF, polymerization initiator) was mixed in a ratio of 1 part and coated onto a PET film to a film thickness of 100 μm. A PET film was also attached to the side not in contact with the film, and the coating was irradiated with a high-pressure mercury lamp (365 nm) at 3000 mJ / cm 2 A cured product was obtained by irradiating the composition with ultraviolet light.

[0141] The curable resin composition, resin sheet and cured product thereof of the present invention are suitable for use in electric and electronic parts such as semiconductor encapsulants, printed wiring boards and build-up laminates.

[0142] [Note] As described above, the present embodiment includes the following disclosures.

[0143] [1] A curable resin composition containing a maleimide compound (A) having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), and an amine compound (B), and satisfying the following formula (I): 1.5≦(mass of maleimide compound (A) content / maleimide equivalent) / (mass of amine compound (B) content / amine equivalent)≦2.5 Formula (I)

[0144] [ka]

[0145] (In formulas (1) and (2), R1 and R2 each independently represent an alkyl group having 1 to 20 carbon atoms or an aromatic group having 1 to 20 carbon atoms which may have a substituent, p is an integer of 0 to 3, and q is an integer of 0 to 4.) [2] The curable resin composition according to item [1] above, wherein the maleimide compound (A) is represented by the following formula (3):

[0146] [ka]

[0147] In formula (3), R1 and R2 each independently represent an alkyl group having 1 to 20 carbon atoms or an aromatic group having 1 to 20 carbon atoms which may have a substituent, p is an integer of 0 to 3, and q is an integer of 0 to 4. n is the number of repetitions, the average value of which is 1. <n<5である。)[3] The curable resin composition according to the above item [1] or [2], wherein the amine compound (B) is an aromatic amine compound. [4] The curable resin composition according to any one of items [1] to [3], wherein the maleimide compound (A) has a maleimide equivalent of 250 g / eq. to 1000 g / eq., and the amine compound (B) has an amine equivalent of 50 g / eq. to 400 g / eq. [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 items [1] to [5] above, further comprising at least one selected from the group consisting of a polymerization initiator, an epoxy resin, an activated ester compound, a phenolic resin, a polyphenylene ether compound, an amine resin other than the amine compound (B), a compound having an ethylenically unsaturated bond, an isocyanate resin, a polyamide resin, a maleimide compound other than the maleimide compound (A), a cyanate ester resin, a polyimide resin, polybutadiene and modified products thereof, polystyrene and modified products thereof, polyethylene and modified products thereof, and a benzoxazine compound. [7] A cured product obtained by curing the curable resin composition according to any one of the above items [1] to [6]. [8] A prepreg comprising a sheet-shaped fiber substrate and the curable resin composition according to any one of the above items [1] to [6]. [9] A cured product obtained by curing the prepreg described in the preceding item [8].

Claims

1. A curable resin composition containing a maleimide compound (A) having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), and an amine compound (B), and satisfying the following formula (I): 1.5≦(mass of maleimide compound (A) content / maleimide equivalent) / (mass of amine compound (B) content / amine equivalent)≦2.5... Formula (I) 【Chemistry 1】 (In formulas (1) and (2), R １ , R ２ each independently represents an alkyl group having 1 to 20 carbon atoms or an aromatic group having 1 to 20 carbon atoms which may have a substituent, p is an integer of 0 to 3, and q is an integer of 0 to 4.

2. The curable resin composition according to claim 1, wherein the maleimide compound (A) is represented by the following formula (3): 【Chemistry 2】 (In formula (3), R １ , R ２ each independently represents an alkyl group having 1 to 20 carbon atoms or an aromatic group having 1 to 20 carbon atoms which may have a substituent, p is an integer of 0 to 3, q ​​is an integer of 0 to 4, n is the number of repetitions, and the average value is 1<n<5.

3. The curable resin composition according to claim 1, wherein the amine compound (B) is an aromatic amine compound.

4. 2. The curable resin composition according to claim 1, wherein the maleimide compound (A) has a maleimide equivalent of 250 g / eq. to 1000 g / eq., and the amine compound (B) has an amine equivalent of 50 g / eq. to 400 g / eq.

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 at least one selected from the group consisting of a polymerization initiator, an epoxy resin, an active ester compound, a phenolic resin, a polyphenylene ether compound, an amine resin other than the amine compound (B), a compound having an ethylenically unsaturated bond, an isocyanate resin, a polyamide resin, a maleimide compound other than the maleimide compound (A), a cyanate ester resin, a polyimide resin, polybutadiene and modified products thereof, polystyrene and modified products thereof, polyethylene and modified products thereof, and a benzoxazine compound.

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

8. A prepreg comprising a sheet-like fiber substrate and the curable resin composition according to any one of claims 1 to 6 held thereon.

9. A cured product obtained by curing the prepreg according to claim 8.

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