Epoxy resin, curable resin composition, cured product, and phenolic resin

Abstract

The present invention provides an epoxy resin with excellent high fluidity and heat resistance, a curable resin composition, and a phenolic resin which is an epoxy resin precursor.　The phenolic resin is obtained by reacting a compound represented by formula (a) and a compound represented by formula (b). (In formula (a), the plurality of Rs are each present independently, and each represent a 1-5C hydrocarbon group. The total of the carbon numbers of the plurality of Rs is 2-8. k is an integer 1-3.)

Description

Epoxy resin, curable resin composition, cured product, and phenolic resin

[0001] The present invention relates to an epoxy resin, a curable resin composition, a cured product, and a phenolic resin having a specific structure, and is suitable for use in electrical and electronic components such as semiconductor encapsulants, printed wiring boards, build-up laminates, and optical waveguide devices, lightweight, high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, and 3D printing applications.

[0002] Epoxy resins have excellent electrical properties (dielectric constant, dielectric dissipation factor, insulation), mechanical properties, adhesive properties, and thermal properties (heat resistance, etc.), and are therefore widely used in the electrical and electronic fields, such as in cast products, laminates, and IC encapsulation materials, as well as in structural materials, adhesives, paints, and other fields.

[0003] In recent years, in the electrical and electronic fields, there has been a demand for further improvements in various properties of resin compositions, such as improved flame retardancy, moisture resistance, adhesion, and dielectric properties, higher purity, lower viscosity for higher filler (inorganic or organic filler) loading, and improved reactivity for shorter molding cycles (Patent Document 1). Furthermore, as structural materials, lightweight materials with excellent mechanical properties are required for aerospace materials, leisure and sports equipment applications, and the like. In particular, in the field of semiconductor encapsulation and substrates (the substrate itself or its peripheral materials), semiconductors have become increasingly complex, with thinner layers, stacked structures, systemization, and three-dimensional structures, requiring extremely high levels of heat resistance and high fluidity. In particular, with the expansion of plastic packaging into automotive applications, the demand for improved heat resistance has become even more stringent. Specifically, the rise in semiconductor operating temperatures has led to the demand for extremely high heat resistance. In particular, with the recent trend toward high-gap semiconductors, there is a need for operating temperatures of 175°C and even 200°C or higher (Non-Patent Documents 1 and 2).

[0004] In the semiconductor encapsulation field, there is a demand for further improvements in various properties, including higher purity resin compositions, moisture resistance, adhesion, dielectric properties, lower viscosity for higher filler (inorganic or organic) loading, and improved reactivity for shorter molding cycles. Furthermore, as semiconductor package shapes evolve, they become thinner, stacked, systemized, and three-dimensional, becoming more complex. As the wiring pitches become increasingly narrower and thinner, poor fluidity of resin compositions can lead to wire sweep. Furthermore, this places a strain on the wire connections, adversely affecting them.

[0005] Furthermore, in flip-chip packages, a technique called mold underfill, which seals the chip without using underfill, has attracted attention as a low-cost manufacturing method. In this method, the resin must pass through the extremely narrow gap between the chip and the package substrate, making filler fineness important. Furthermore, sealing resins used in redistribution layers in wafer-level packages and interlayer insulating films used in build-up layers must be thin, and fine fillers are required to reduce the linear expansion coefficient. Meanwhile, finer fillers increase the surface area, which increases the viscosity of the system and can lead to voids, so lower viscosity resin compositions are required.

[0006] 2008 STRJ Report, Semiconductor Roadmap Special Committee, FY2008 Report, Chapter 8, p. 1-1, [online], March 2009, JEITA (Japan Electronics and Information Technology Industries Association), Semiconductor Technology Roadmap Special Committee, [Retrieved May 30, 2012], <http: / / strj-jeita.elisasp.net / strj / nenjihoukoku-2008.cfm> Takakura Nobuyuki et al., Matsushita Electric Industrial Technical Report, Automotive Device Technology, High Temperature Operation C for Automotive Applications, No. 74, Japan, May 31, 2001, pp. 35-40

[0007] JP 2015-147854 A JP 2008-195751 A JP 2010-018669 A

[0008] One method for lowering the viscosity of an epoxy resin composition is to add a low-viscosity epoxy resin, and Patent Document 2 discusses an epoxy resin composition to which a low-molecular-weight bisphenol F epoxy resin has been added. However, low-viscosity epoxy resins often have poor heat resistance, making it difficult to satisfy the need for high heat resistance.

[0009] Another method is to reduce the viscosity of the epoxy resin itself. Specifically, a method of reducing the molecular weight of the epoxy resin is mentioned, and in Patent Document 3, a low-molecular-weight cresol novolac epoxy resin is investigated. However, although the fluidity improves when the molecular weight of the epoxy resin is reduced and the molecular weight distribution becomes narrower, the heat resistance tends to decrease, and Patent Document 3 is no exception.

[0010] Given this background, there is a need for the development of materials that can ensure high fluidity without significantly impairing heat resistance.

[0011] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an epoxy resin, a curable resin composition, and a phenolic resin, which is a precursor of the epoxy resin, that are excellent in high fluidity and heat resistance.

[0012] That is, the present invention relates to the following [1] to [8]. In this application, "(numerical value 1) to (numerical value 2)" indicates that the upper and lower limits are included. [1] A phenolic resin obtained by reacting a compound represented by the following formula (a) with a compound represented by the following formula (b):

[0013]

[0014] (In formula (a), each of the multiple R's independently represents a hydrocarbon group having 1 to 5 carbon atoms. The total number of carbon atoms in the multiple R's is 2 to 8. k is an integer of 1 to 3.) [2] The phenolic resin according to the preceding item [1], wherein the content of a compound represented by the following formula (c) is 75 to 95 area % as determined by differential refractometry detection in gel permeation chromatography:

[0015]

[0016] (In formula (c), each R independently represents a hydrocarbon group having 1 to 5 carbon atoms. In each benzene ring substituted with R, the total number of carbon atoms in the plurality of R is 2 to 8. k is an integer of 1 to 3.) [3] An epoxy resin obtained by reacting the phenolic resin according to the above item [1] or [2] with epihalohydrin. [4] A curable resin composition containing the epoxy resin according to the above item [3]. [5] The curable resin composition according to the above item [4], further containing a curing agent and / or a curing accelerator. [6] The curable resin composition according to the above item [4], further containing at least one selected from the group consisting of a curing accelerator, a polymerization initiator, an epoxy resin, an active ester compound, a phenolic resin, a polyphenylene ether compound, an amine resin, a compound having an ethylenically unsaturated bond, an isocyanate resin, a polyamide resin, a maleimide compound, 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 [4] to [6]. [8] An epoxy resin represented by the following formula (d-1):

[0017]

[0018] (In formula (d-1), each R independently represents a hydrocarbon group having 1 to 5 carbon atoms. In each benzene ring substituted with R, the total number of carbon atoms of the R is 2 to 8. k is an integer of 1 to 3. n is the average number of repetitions and is 1 to 20.)

[0019] According to the present invention, it is possible to provide an epoxy resin, a curable resin composition, and a cured product thereof that are highly fluid and have excellent heat resistance.

[0020] 1 shows a GPC chart of Synthesis Example 1. FIG. 2 shows a GPC chart of Synthesis Example 2.

[0021] Hereinafter, an embodiment of the present invention (hereinafter also referred to as "the present embodiment") will be described in further detail.

[0022] The phenolic resin of the present embodiment is obtained by reacting a compound represented by the following formula (a) with a compound represented by the following formula (b).

[0023]

[0024] In the formula (a), each R independently represents a hydrocarbon group having 1 to 5 carbon atoms, preferably a hydrocarbon group having 1 to 4 carbon atoms. Having 6 or more carbon atoms may impair heat resistance and reduce the elastic modulus of the cured product, which is undesirable from the viewpoint of causing warpage of the substrate when applied to a board material. Without a hydrocarbon group, the cured product may be prone to water absorption, potentially causing swelling during solder reflow. The total number of carbon atoms in each independently present R is 2 to 8, preferably 2 to 6, and more preferably 2 to 5. If the total number of carbon atoms in R is 1, the effect of reducing water absorption may not be fully achieved. If the total number of carbon atoms is 9 or more, the viscosity may increase due to an increase in molecular weight, and heat resistance may decrease. From the viewpoint of achieving both high fluidity and heat resistance, the total number of carbon atoms in R is preferably 2 to 8. k represents an integer from 1 to 3, preferably 2 to 3. For example, if k=2 and all R are methyl groups, the total number of carbon atoms in R is 2.

[0025] As the compound represented by the above formula (a), it is preferable that the compound has alkyl groups at the 2- and 5-positions (or the 3- and 6-positions) relative to the phenolic hydroxyl group. By introducing hydrocarbon groups into these substitution positions, it is possible to obtain phenolic resins with narrow molecular weight distributions and epoxy resins derived therefrom. There are no particular limitations on the compound as long as it has alkyl groups at the 2- and 5-positions (or the 3- and 6-positions) relative to the phenolic hydroxyl group, but preferred examples include 3-methyl-6-t-butylphenol, thymol, carvacrol, and 2,5-dimethylphenol.

[0026] The compound represented by formula (b) has a hydroxyl group at the ortho position of the aldehyde group, and as a result of this, after derivatization into a phenolic resin or an epoxy resin, steric hindrance occurs, which makes it possible to achieve a high elastic modulus and low water absorption of the cured product.

[0027] The reaction between the compound represented by the formula (a) and the compound represented by the formula (b) may be carried out by any known synthesis method, for example, a method in which the reaction is carried out in a solvent in the presence of an acid catalyst.

[0028] The compound of formula (a) is preferably charged in an amount 1.1 to 8 times by mole relative to the compound of formula (b), more preferably 1.25 to 6 times by mole, and even more preferably 1.5 to 4 times by mole. If the amount is less than 1.1 times by mole, the resulting polymer becomes too high, making water washing difficult and significantly reducing the fluidity of the resin. If the amount is more than 8 times by mole, the yield per batch is significantly reduced and waste is also increased, which is undesirable. During the reaction, acid catalysts that can be used include hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, p-toluenesulfonic acid, and methanesulfonic acid, as well as Lewis acids such as aluminum chloride and zinc chloride, activated clay, acid clay, white carbon, zeolite, and silica alumina, and acidic ion exchange resins. These may be used alone or in combination. The amount of catalyst used is 0.01 to 25% by mass, preferably 0.1 to 15% by mass, based on the total mass of the reaction substrates, phenols (compounds of formula (a) above) and salicylaldehyde (compounds of formula (b) above). Using too much catalyst is undesirable because stirring during the synthesis reaction may become difficult and unnecessary waste may increase. Examples of solvents that can be used include water-insoluble solvents such as aromatic solvents such as toluene and xylene, aliphatic solvents such as cyclohexane and n-hexane, ethers such as diethyl ether and diisopropyl ether, ester solvents such as ethyl acetate and butyl acetate, and ketone solvents such as methyl isobutyl ketone and cyclopentanone, as well as alcoholic solvents such as methanol, ethanol, and isopropanol. However, the solvent is not limited to these, and two or more solvents may be used in combination. Furthermore, an aprotic polar solvent may be used in combination with the water-insoluble solvent. Examples of suitable solvents include dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, and N-methylpyrrolidone, and two or more of these may be used in combination. The reaction temperature is preferably 20 to 180°C, more preferably 40 to 160°C, and even more preferably 50 to 130°C. If the reaction temperature is too high, the methine structure of the trisphenolmethane structure may decompose, and if the reaction temperature is too low, the reaction may not proceed sufficiently.After the reaction is complete, the acidic catalyst may be neutralized with an alkaline aqueous solution or the like, followed by solvent recovery to obtain the target phenolic resin together with the neutralized salt. Alternatively, a water-insoluble organic solvent may be added to the oil layer, followed by repeated washing with water until the wastewater becomes neutral, and then the solvent may be removed under heating and reduced pressure to obtain the target phenolic resin. When activated clay or an ion exchange resin is used, the reaction solution is filtered after the reaction is complete to remove the catalyst, and the solvent is recovered to obtain the target phenolic resin. The residual monomer content of the compound represented by formula (a) is preferably 0.01 to 10% by mass, more preferably 0.05 to 7.5% by mass, and even more preferably 0.1 to 5% by mass. The amount of this monomer affects the amount of residual low-molecular-weight epoxy resin, which in turn affects heat resistance and other properties.

[0029] The phenolic resin obtained by reacting the compound represented by formula (a) with the compound represented by formula (b) contains 75 to 95 area % of the compound represented by formula (c) below, as detected by a differential refractometer in gel permeation chromatography analysis. If the content of the compound represented by formula (c) below is less than 75 area %, the phenolic resin of this embodiment, the epoxy resin made therefrom, and the curable resin composition containing them may not have sufficient fluidity, while if it exceeds 95 area %, the phenolic resin of this embodiment, the epoxy resin made therefrom, and the curable resin composition containing them may not have sufficient heat resistance, and may be highly crystalline, resulting in reduced solvent solubility.

[0030]

[0031] In the formula (c), multiple R's each independently represent a hydrocarbon group having 1 to 5 carbon atoms. In each benzene ring substituted with R, the total number of carbon atoms in the multiple R's is 2 to 8. k is an integer of 1 to 3. The preferred values ​​of R and k are the same as those in the formula (a).

[0032] The number average molecular weight (Mn) of the phenolic resin obtained by reacting the compound represented by formula (a) with the compound represented by formula (b) is preferably 300 to 1500, more preferably 325 to 1000, and even more preferably 350 to 800. If the number average molecular weight is below 300, there is a risk of reduced heat resistance due to residual raw materials, etc. If the number average molecular weight is above 1500, there is a risk of reduced fluidity due to increased molecular weight.

[0033] The weight-average molecular weight (Mw) of the phenolic resin obtained by reacting the compound represented by formula (a) with the compound represented by formula (b) is preferably 300 to 1500, more preferably 325 to 1000, and even more preferably 350 to 800. If the weight-average molecular weight is below 300, there is a risk of reduced heat resistance due to residual raw materials, etc. If the weight-average molecular weight is above 1500, there is a risk of reduced fluidity due to increased molecular weight.

[0034] The hydroxyl equivalent of the phenolic resin obtained by reacting the compound represented by formula (a) with the compound represented by formula (b) is preferably 100 to 200 g / eq., more preferably 110 to 180 g / eq., and even more preferably 120 to 160 g / eq. The hydroxyl equivalent may be calculated from the area % of gel permeation chromatography (GPC) analysis, or may be measured by titration. When measuring by titration, for example, a sample is acetylated using acetic anhydride in a pyridine solution, and after acetylation is complete, the remaining acid anhydride is decomposed with water, and the resulting solution is titrated with a 0.5 N KOH ethanol solution using a potentiometric titrator to measure the amount of free acetic acid, and the hydroxyl equivalent can be determined from the results.

[0035] The content of the polymer component of the compound represented by formula (c) is preferably 1 to 25 area % and more preferably 3 to 15 area % as determined by gel permeation chromatography analysis (detection with a differential refractometer). If it exceeds 25 area %, fluidity may decrease, and if it is less than 3 area %, solvent solubility and heat resistance may decrease.

[0036] A typical structure of the phenolic resin obtained by reacting the compound represented by the above formula (a) with the compound represented by the above formula (b) can be represented by the following formula (c-1).

[0037]

[0038] In the above formula (c-1), multiple R's each independently represent a hydrocarbon group having 1 to 5 carbon atoms. In each benzene ring substituted with R, the total number of carbon atoms in the multiple R's is 2 to 8. k is an integer from 1 to 3. The preferred values ​​of R and k are the same as those in the above formula (a). n is the average number of repeating units, and is 1 to 20, preferably 1 to 10, and more preferably 1 to 5. If n is less than 1, there is a risk of a large amount of residual monomer, resulting in a decrease in heat resistance. If n is more than 20, there is a risk of insufficient fluidity being ensured. n can be determined by GPC analysis and may be calculated from the area % of each peak or from the number average molecular weight (Mn).

[0039] The epoxy resin of this embodiment will be described below. The epoxy resin of this embodiment can be obtained by reacting a phenolic resin obtained by reacting a compound represented by formula (a) above with a compound represented by formula (b) above with an epihalohydrin. For example, the epoxy resin can be obtained by subjecting the phenolic resin of this embodiment to an addition or ring-closing reaction with an epihalohydrin in the presence of a solvent and a catalyst. The amount of epihalohydrin used is typically 1.0 to 20.0 mol, preferably 1.5 to 10.0 mol, per mol of phenolic hydroxyl groups in the phenolic resin.

[0040] Examples of alkali metal hydroxides that can be used in the epoxidation reaction include sodium hydroxide and potassium hydroxide. The alkali metal hydroxide may be a solid or an aqueous solution. When an aqueous solution is used, the alkali metal hydroxide may be continuously added to the reaction system while continuously distilling water and epihalohydrin under reduced pressure or normal pressure, followed by liquid separation to remove water and continuously returning the epihalohydrin to the reaction system. The amount of alkali metal hydroxide used is typically 0.9 to 2.5 moles, preferably 0.95 to 1.5 moles, per mole of phenolic hydroxyl groups in the phenolic resin. If the amount of alkali metal hydroxide used is too small, the reaction will not proceed sufficiently. On the other hand, excessive use of more than 2.5 moles of alkali metal hydroxide per mole of phenolic hydroxyl groups in the phenolic resin will result in the production of unnecessary waste by-products.

[0041] To accelerate the reaction, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide, or trimethylbenzylammonium chloride may be added as a catalyst. The amount of quaternary ammonium salt used is typically 0.1 to 15 g, and preferably 0.2 to 10 g, per mole of phenolic hydroxyl groups in the phenolic resin. If the amount used is too small, a sufficient reaction acceleration effect cannot be obtained, while if the amount used is too large, the amount of quaternary ammonium salt remaining in the epoxy resin increases, which may cause a deterioration in electrical reliability.

[0042] In order to advance the epoxidation reaction, it is preferable to add an alcohol such as methanol, ethanol, or isopropyl alcohol, or an aprotic polar solvent such as dimethyl sulfone, dimethyl sulfoxide, tetrahydrofuran, or dioxane. When an alcohol is used, the amount used is usually 2 to 50 mass%, preferably 4 to 20 mass%, based on the amount of epihalohydrin used. When an aprotic polar solvent is used, the amount used is usually 5 to 100 mass%, preferably 10 to 80 mass%, based on the amount of epihalohydrin used. The reaction temperature is usually 30 to 90°C, preferably 35 to 80°C. The reaction time is usually 0.5 to 100 hours, preferably 1 to 30 hours.

[0043] After the reaction is complete, the reaction product is washed with water, or heated under reduced pressure to remove the epihalohydrin and solvent. Furthermore, to obtain an epoxy resin with a reduced hydrolyzable halogen content, the recovered epoxy resin can be dissolved in a solvent such as toluene or methyl isobutyl ketone, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to the reaction mixture to ensure ring closure. In this case, the amount of alkali metal hydroxide used is typically 0.01 to 0.3 mol, preferably 0.05 to 0.2 mol, per mol of phenolic hydroxyl groups in the phenolic resin used for glycidylation. The reaction temperature is typically 50 to 120°C, and the reaction time is typically 0.5 to 24 hours. After the reaction is complete, the resulting salt is removed by filtration, washing with water, or the like, and the solvent is then distilled off under reduced pressure with heating to obtain the epoxy resin of this embodiment.

[0044] The softening point of the epoxy resin of this embodiment is preferably 40 to 150°C, more preferably 45 to 125°C, and even more preferably 50 to 100°C. If the softening point is higher than 150°C, solvent is likely to remain when the resin is removed, leading to voids during curing. Furthermore, significant production issues arise, such as increased foaming during solvent distillation. On the other hand, if the softening point is 40°C or lower, heat resistance and thermal decomposition resistance are adversely affected. Furthermore, the epoxy equivalent is preferably 150 to 300 g / eq., more preferably 160 to 275 g / eq., and even more preferably 170 to 250 g / eq. If the epoxy equivalent is less than 150 g / eq., residual epichlorohydrin and large amounts of epoxidized impurities remain, potentially resulting in deterioration of properties. Furthermore, if the epoxy equivalent exceeds 300 g / eq., reduced heat resistance becomes an issue. The ICI viscosity of the epoxy resin of this embodiment at 150°C is preferably 0.01 to 0.5 Pa·s, more preferably 0.01 to 0.4 Pa·s, and even more preferably 0.01 to 0.3 Pa·s. If the ICI viscosity at 150°C exceeds 0.5 Pa·s, it is difficult to obtain sufficient fluidity. In this embodiment, the steric hindrance of the alkyl group derived from the compound of formula (a) and the orientation of the hydroxyl group derived from the compound of formula (b) (having a hydroxyl group at the ortho position of the aldehyde) are utilized to control the gel time during curing, thereby improving fluidity. If the gel time during curing is too short, the resin will not flow well during molding.

[0045] The epoxy resin of this embodiment contains a compound represented by the following formula (d) in an amount of 75 to 95 area % as detected by a differential refractometer in gel permeation chromatography analysis. If the content of the compound represented by the following formula (d) is less than 75 area %, the epoxy resin of this embodiment and the curable resin composition containing it may not have sufficient fluidity, while if it exceeds 95 area %, the epoxy resin of this embodiment and the curable resin composition containing it may not have sufficient heat resistance and may have high crystallinity and reduced solvent solubility.

[0046]

[0047] In the above formula (d), multiple R's each independently represent a hydrocarbon group having 1 to 5 carbon atoms. In each benzene ring substituted with R, the total number of carbon atoms in the multiple R's is 2 to 8. k is an integer of 1 to 3. The preferred values ​​of R and k are the same as those in the above formula (a).

[0048] A representative structure of the epoxy resin of this embodiment can be represented by the following formula (d-1).

[0049] In the above formula (d-1), multiple R's each independently represent a hydrocarbon group having 1 to 5 carbon atoms. In each benzene ring substituted with R, the total number of carbon atoms in the multiple R's is 2 to 8. k is an integer of 1 to 3. n is the average number of repeating groups and is 1 to 20. The preferred values ​​of R, k, and n are the same as those in the above formula (c-1).

[0050] The curable resin composition of this embodiment will be described below. The epoxy resin used in the curable resin composition of this embodiment may be the epoxy resin of this embodiment described above, used alone, or may be used in combination with other epoxy resins. When used in combination, the proportion of the epoxy resin of this embodiment in the total epoxy resin is preferably 10 to 98 mass%, more preferably 30 to 95 mass%, and even more preferably 60 to 95 mass%. By adding the epoxy resin of this embodiment in an amount of 10% or more, high fluidity and high heat resistance can be achieved.

[0051] Specific examples of other epoxy resins that can be used in combination with the epoxy resin of this embodiment include bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol, bisphenol AD, etc.) or phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes (formaldehyde, acetaldehyde, alkyl aldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, chlorine ... polymers of the phenols with various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc.); polycondensates of the phenols with ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.); polycondensates of the phenols with aromatic dimethanols (benzenedimethanol, biphenyldimethanol, etc.); polycondensates of the phenols with aromatic dichloromethyl ketones (α,α'-dichloroxylene, bischloromethylbiphenyl, etc.); polycondensates of the above-mentioned phenols with aromatic bisalkoxymethyls (bismethoxymethylbenzene, bismethoxymethylbiphenyl, bisphenoxymethylbiphenyl, etc.); polycondensates of the above-mentioned bisphenols with various aldehydes, or glycidyl ether epoxy resins, alicyclic epoxy resins, glycidylamine epoxy resins, glycidyl ester epoxy resins, etc., obtained by glycidylating polycondensates of the above-mentioned bisphenols with various aldehydes or alcohols, but the epoxy resins are not limited to these, so long as they are commonly used. Specific examples include "RE310S" and "RE410S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol A type epoxy resins), "RE303S", "RE304S", "RE403S", and "RE404S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy resins), "HP4032", "HP4032D", and "HP4032SS" (all manufactured by DIC Corporation, naphthalene type epoxy resins), "jER (registered trademark) 828US", "jER828EL", "825", and "828EL" (all manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resins), "jER807", and "jER1750" (all manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resins), and "jER152 (manufactured by Mitsubishi Chemical Corporation, phenol novolac type epoxy resin), "jER630", "jER630LSD" (both manufactured by Mitsubishi Chemical Corporation, glycidylamine type epoxy resin), "ZX1059" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin), "EX-721" (manufactured by Nagase ChemteX Corporation, glycidyl ester type epoxy resin), "Celloxide (registered trademark) 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" (both manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., liquid 1,4-glycidylcyclohexane type epoxy resin), "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", "HP-7200HH", "HP-7200H" (all manufactured by DIC Corporation, dicyclopentadiene type epoxy resin), "EXA-7311 "," "EXA-7311-G3," "EXA-7311-G4," "EXA-7311-G4S," and "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," and "NC-7300" (all manufactured by Nippon Kayaku Co., Ltd., naphthol-cresol novolac type epoxy resin), "NC-3000H," "NC-3000," "NC-3000L," and "NC-3100" (all manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin), "XD-1000-2L", "XD-1000-L", "XD-1000-H" (all manufactured by Nippon Kayaku Co., Ltd., dicyclopentadiene type epoxy resin), "ESN475V" (manufactured by Nippon Steel & 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, bixylenol type epoxy resin) Examples of epoxy resins 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.

[0052] Curing agents that can be used in the curable resin composition of this embodiment include amine-based curing agents, acid anhydride-based curing agents, amide-based curing agents, phenol-based curing agents, and the active ester compounds described below. Specific examples of usable curing agents include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 2,2'-diaminodiphenylsulfone, diethyltoluenediamine, dimethylthiotoluenediamine, diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and the like. diphenylmethane, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, 4,4'-diamino-3,3',5,5'-tetramethyldiphenylmethane, 4,4'-diamino-3,3',5,5'-tetraethyldiphenylmethane, 4,4'-diamino-3,3',5,5'-tetraisopropyldiphenylmethane, 3,3'-diisopropyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-4,4'-diaminodiphenylmethane, 3,3'-diisopropyl propyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diisopropyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-5,5'-diisopropyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetra-t-butyl-4,4' -diaminodiphenylmethane, 4,4'-methylenebis(N-methylaniline), bis(aminophenyl)fluorene, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 1,3'-bis(4-aminophenoxy)benzene, 1,4'-bis(4-aminophenoxy)benzene, 1,4'-bis(4-aminophenoxy)biphenyl,Examples of suitable amines include 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, naphthalenediamine, benzidine, dimethylbenzidine, aromatic amine compounds such as the aromatic amine compounds described in Synthesis Examples 1 and 2 of WO 2017 / 170551, 1,3-bis(aminomethyl)cyclohexane, isophoronediamine, 4,4'-methylenebis(cyclohexylamine), norbornanediamine, ethylenediamine, propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, dimer diamine, metaxylylenediamine, and triethylenetetramine, but are not limited thereto. Suitable amines can be used depending on the properties desired to be imparted to the composition. To ensure pot life, aromatic amines are preferred, while aliphatic amines are preferred when rapid curing is desired. By using an amine compound containing a bifunctional component as a curing agent, a highly linear network can be constructed during the curing reaction, and particularly excellent toughness can be exhibited. Further, amide compounds such as polyamide resins synthesized from dicyandiamide, a dimer of linolenic acid, and ethylenediamine; acid anhydride compounds such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride; bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol, bisphenol AD, etc.) or phenols (phenol, alkyl-substituted phenols) can be used. polycondensates of phenols (e.g., aromatic substituted phenols, naphthol, alkyl-substituted naphthols, dihydroxybenzenes, alkyl-substituted dihydroxybenzenes, dihydroxynaphthalenes) with various aldehydes (e.g., formaldehyde, acetaldehyde, alkyl aldehydes, benzaldehyde, alkyl-substituted benzaldehydes, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural), or polycondensates of the above phenols with various diene compounds (e.g., dicyclopentadiene, terpenes,Examples of suitable phenolic compounds include, but are not limited to, polymers of the phenols with ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, fluorenone, etc.), polycondensates of the phenols with aromatic dimethanols (benzenedimethanol, biphenyldimethanol, etc.), polycondensates of the phenols with aromatic dichloromethyls (α,α'-dichloroxylene, bischloromethylbiphenyl, etc.), polycondensates of the phenols with aromatic bisalkoxymethyls (bismethoxymethylbenzene, bismethoxymethylbiphenyl, bisphenoxymethylbiphenyl, etc.), polycondensates of the bisphenols with various aldehydes, and modified products thereof.

[0053] [Active Ester Compound] The active ester compound refers to a compound containing at least one ester bond in its structure, and having an aliphatic chain, an aliphatic ring, or an aromatic ring bonded to both sides of the ester bond. Examples of active ester compounds include compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. These active ester compounds are obtained by a condensation reaction between at least one compound selected from a carboxylic acid compound, an acid chloride, and a thiocarboxylic acid compound and at least one compound selected from a hydroxy compound and a thiol compound. In particular, from the viewpoint of improving heat resistance, active ester compounds obtained from a carboxylic acid compound or an acid chloride and a hydroxy compound are preferred, and the hydroxy compound is preferably a phenol compound or a naphthol compound. Active ester compounds may be used alone or in combination of two or more.

[0054] 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.

[0055] 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.

[0056] 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 molecule of dicyclopentadiene with two molecules of phenol.

[0057] 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 phenol novolac, active ester compounds containing a benzoylated 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.

[0058] 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, and "EXB9416-70BK" (manufactured by DIC Corporation) as an active ester compound containing a naphthalene structure. Examples of active ester compounds containing acetylated 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), active ester curing agents containing phosphorus atoms include "EXB-9050L-62M" (manufactured by DIC Corporation), and active ester compounds containing a bisphenol A structure include "Unifiner W-575".

[0059] In the curable resin composition of this embodiment, the amount of curing agent used is preferably 0.5 to 1.5 equivalents, and particularly preferably 0.6 to 1.2 equivalents, relative to 1 equivalent of the epoxy group of the epoxy resin. By using an amount of 0.5 to 1.5 equivalents, good curing properties can be obtained.

[0060] When the curing reaction is carried out using the above curing agent, a curing accelerator may be used in combination. Examples of curing accelerators that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, and 2-ethyl-4-methylimidazole, tertiary amines such as 2-(dimethylaminomethyl)phenol, triethylenediamine, triethanolamine, and 1,8-diazabicyclo(5,4,0)undecene-7, organic phosphines such as triphenylphosphine, diphenylphosphine, and tributylphosphine, metal compounds such as tin octoate, tetra-substituted phosphonium tetra-substituted borates such as tetraphenylphosphonium tetraphenylborate and tetraphenylphosphonium ethyltriphenylborate, tetraphenylboron salts such as 2-ethyl-4-methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate, and carboxylic acid compounds such as benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthoic acid, and salicylic acid. From the viewpoint of accelerating the curing reaction between the amine compound and the epoxy resin, a carboxylic acid compound such as salicylic acid is preferred. The curing accelerator is used in an amount of 0.01 to 15 parts by mass per 100 parts by mass of the epoxy resin, as needed.

[0061] Furthermore, inorganic fillers can be added to the curable resin composition of this embodiment as needed. Examples of inorganic fillers include, but are not limited to, powders such as crystalline silica, fused silica, hollow silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, aluminum hydroxide, magnesium hydroxide, zircon, calcium silicate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, zirconium tungstate phosphate, clay, zirconia, fosterite, steatite, spinel, titania, talc, mica powder, zinc oxide, hydrotalcite, boehmite, and carbon black, or beads obtained by spheroidizing these. These may be used alone or in combination of two or more. The amount of these inorganic fillers used varies depending on the application. For example, when used as an encapsulant for semiconductors, the inorganic fillers are used in a proportion of 20% by mass or more, more preferably 30% by mass or more, in terms of the heat resistance, moisture resistance, mechanical properties, flame retardancy, and the like of the cured product of the curable resin composition. In particular, the inorganic fillers are used in a proportion of 70 to 95% by mass in order to improve the linear expansion coefficient with the lead frame.

[0062] A mold release agent can be blended into the curable resin composition of this embodiment to improve mold release during molding. Any conventionally known mold release agent can be used, including ester waxes such as carnauba wax and montan wax, fatty acids such as stearic acid and palmitic acid and their metal salts, and polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene. These may be used alone or in combination of two or more. The blend amount of these mold release agents is preferably 0.5 to 3 mass % of the total organic components. If the amount is less than this, mold release from the mold is poor, and if the amount is too much, adhesion to a lead frame or the like is poor.

[0063] A coupling agent can be blended into the curable resin composition of this embodiment to enhance adhesion between the inorganic filler and the resin component. Any conventionally known coupling agent can be used, including, for example, various alkoxysilane compounds such as vinylalkoxysilane, epoxyalkoxysilane, styrylalkoxysilane, methacryloxyalkoxysilane, acryloxyalkoxysilane, aminoalkoxysilane, mercaptoalkoxysilane, and isocyanatoalkoxysilane, alkoxytitanium compounds, and aluminum chelates. These may be used alone or in combination of two or more. The coupling agent may be added by first treating the surface of the inorganic filler with the coupling agent and then kneading it with the resin, or by mixing the coupling agent with the resin and then kneading the inorganic filler.

[0064] Furthermore, known additives may be blended into the curable resin composition of the present embodiment as needed. Specific examples of usable additives include polybutadiene and modified polybutadiene, modified acrylonitrile copolymers, polyphenylene ether, polystyrene, polyethylene, polyimide, fluororesin, maleimide compounds, cyanate ester compounds, silicone gel, silicone oil, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

[0065] In addition to the components described above, the curable resin composition of this embodiment may also contain the following components. Examples include carboxylic acid compounds, maleimide compounds, cyanate compounds, isocyanate compounds, polyphenylene ether compounds, compounds having an ethylenically unsaturated bond, polyamide compounds, polyimide compounds, allyl compounds, polybutadiene and modified products thereof, polystyrene and modified products thereof, polyethylene and modified products thereof, benzoxazine compounds, flame retardants, and polymerization initiators. These compounds may be used alone or in combination. Among these compounds, polyphenylene ether compounds, compounds having an ethylenically unsaturated bond, cyanate ester resins, polybutadiene and modified products thereof, polystyrene and modified products thereof, benzoxazine compounds, flame retardants, and polymerization initiators 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 total 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 compound of this embodiment. The preferred lower limit is 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 being within the above range, the effect of the heat resistance of the compound of this embodiment can be utilized while the effect of each compound added can be enhanced. The following examples of these components can be used.

[0066] [Carboxylic Acid Compound] Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, 5-hydroxyisophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodiumsulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, cyclohexanedicarboxylic acid, biphenyldicarboxylic acid, naphthalenedicarboxylic acid, benzophenonedicarboxylic acid, furandicarboxylic acid, 4,4'-dicarboxydiphenyl ether, and 4,4'-dicarboxydiphenyl sulfide. Commercially available products include G4-142MHR (manufactured by Nippon Kayaku Co., Ltd.).

[0067] [Maleimide Compound] Examples of the maleimide compound include phenylmaleimide, 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, and Xylox-type maleimide compounds (anilix). maleimide, manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenylaralkyl-type maleimide compounds (solidified by distilling off the solvent under reduced pressure from a resin solution containing the maleimide compound (M2) described in Example 4 of JP 2009-001783 A), bisaminocumylbenzene-type maleimide (maleimide compounds described in WO 2020 / 054601 A), maleimide compounds having an indane structure described in JP 6629692 A or WO 2020 / 217679 A, ​​polymaleimides derived from aromatic vinyl compounds and anilines described in JP 2023-007239 A, and the like, as described in MATERIAL STAGE Vol. 18, No. 12 2019 "Continued Story of Epoxy Resin CAS Numbers - Curing Agent CAS Number Memorandum No. 31 Bismaleimide (1)" and MATERIAL STAGE Vol. 19, No. 2 2019, "Continued Epoxy Resin CAS Number Story - Curing Agent CAS Number Memorandum No. 32 Bismaleimide (2)." Commercially available products include MIR-3000-70MT (biphenylaralkyl maleimide compound, manufactured by Nippon Kayaku Co., Ltd.) and MIZ-001 (manufactured by Nippon Kayaku Co., Ltd.).

[0068] [Cyanate Compound] The cyanate compound is a cyanate compound obtained by reacting a phenol compound with a cyanogen halide, and specific examples include 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 a phenol-dicyclopentadiene co-condensate in which the hydroxyl groups have been converted to cyanate groups. An example of a commercially available product is CYTESTER TA (bisphenol A-type cyanate resin, manufactured by Mitsubishi Gas Chemical Company, Inc.). These may be used alone or in combination. Furthermore, the cyanate compound whose synthesis method is described in JP 2005-264154 A is particularly preferred as the cyanate compound because of its low moisture absorption, flame retardancy, and excellent dielectric properties. If necessary, the cyanate compound may 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.

[0069] 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 cyanate compound and curable resin composition.

[0070] [Isocyanate Compound] An isocyanate compound is a compound having two or more isocyanate groups in the molecule. Examples of the isocyanate compound include 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 compounds of isocyanate monomers or isocyanate compounds obtained by trimerization of the above diisocyanate compounds; and polyisocyanates obtained by a urethanization reaction of the above isocyanate compounds with polyol compounds, but are not limited to these. These may be used alone or in combination.

[0071] [Polyphenylene Ether Compound] From the viewpoint 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 (manufactured by SABIC Corporation, a polyphenylene ether compound having a methacrylic group), OPE-2St 1200, and OPE-2st 2200 (all manufactured by Mitsubishi Gas Chemical Company, polyphenylene ether compounds 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 number average molecular weight is less than 500, the heat resistance of the cured product tends to be insufficient. Furthermore, if the number average molecular weight is greater than 5000, the melt viscosity increases, and sufficient fluidity cannot be obtained, which tends to result in molding defects. Furthermore, the reactivity decreases, the curing reaction takes a long time, and the amount of unreacted polyphenylene ether not incorporated into the curing system increases, which lowers the glass transition temperature of the cured product and reduces the heat resistance of the cured product. If the number average molecular weight of the polyphenylene ether compound is 500 to 5,000, it is possible to exhibit excellent heat resistance and moldability while maintaining excellent dielectric properties. The number average molecular weight here can be measured specifically using gel permeation chromatography or the like.

[0072] The polyphenylene ether compound may be one obtained by a polymerization reaction or one obtained 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. Furthermore, these compounds may be used as raw materials and reacted with a compound having an ethylenically unsaturated bond, such as methacrylic acid chloride, acrylic acid chloride, or chloromethylstyrene, to impart radical polymerizability. A polyphenylene ether compound obtained by a redistribution reaction may be obtained, for example, by heating a high-molecular-weight polyphenylene ether compound in a solvent such as toluene in the presence of a phenolic compound and a radical initiator to cause a redistribution reaction. Such polyphenylene ether compounds obtained by a redistribution reaction are preferred because they have hydroxyl groups derived from 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, polyphenylene ether compounds obtained by a polymerization reaction are preferred because they exhibit excellent fluidity.

[0073] 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. Furthermore, 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.

[0074] 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 curable resin composition. A content of the polyphenylene ether compound within the above range is preferable in that it not only has excellent heat resistance and the like, but also allows a cured product to be obtained that fully exhibits the excellent dielectric properties of the polyphenylene ether compound.

[0075] [Compound Having an Ethylenically Unsaturated Bond] The compound having an ethylenically unsaturated bond is a compound having one or more ethylenically unsaturated bonds in the molecule that can be polymerized by heat or light, regardless of whether a polymerization initiator is used. Examples of the compound containing an ethylenically unsaturated bond include acenaphthylene, indene, styrene, divinylbenzene, reaction products of the phenol resins with ethylenically unsaturated bond-containing halogen-based compounds (chloromethylstyrene, allyl chloride, methallyl chloride, acrylic acid chloride, methacrylic acid chloride, etc.), reaction products of ethylenically unsaturated bond-containing phenols (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) with halogen-based compounds (1,4-bis(chloromethyl)benzene, 4,4'-bis(chloromethyl)biphenyl, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuric chloride, etc.), reaction products of epoxy resins or alcohols with (meth)acrylic acids (acrylic acid, methacrylic acid, etc.), and acid-modified products thereof. Specific examples include, but are not limited to, BVPE (bisvinylphenylethane), compounds having a vinylbenzene structure described in WO2021 / 100658, KAYARAD R-684, etc. These may be used alone or in combination.

[0076] [Polyamide Resin] Examples of polyamide resins include a reaction product of one or more of diamines, diisocyanates, and oxazolines with dicarboxylic acids, a reaction product of diamines with acid chlorides, and ring-opening polymerization products of lactam compounds. These may be used alone or in combination. Specific examples of the above-mentioned raw materials are listed below, but are not limited thereto.<Diamines> Ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-diaminopentane, 2-methyl diamino-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 aniline, 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-aminophenoxy)biphenyl] 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.<Diisocyanates> benzene diisocyanate, toluene diisocyanate, 1,3-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)cyclohexane, bis(4-isocyanatophenyl)methane, isophorone diisocyanate, 1,3-bis(2-isocyanato-2-propyl)benzene, 2,2-bis(4-isocyanatophenyl)hexafluoropropane, dicyclohexylmethane-4,4′-diisocyanate, and the like. <Dicarboxylic acids> 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-sodiumsulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, cyclohexanedicarboxylic acid, biphenyldicarboxylic acid, naphthalenedicarboxylic acid, benzophenonedicarboxylic acid, furandicarboxylic acid, 4,4'-dicarboxydiphenyl ether, 4,4'-dicarboxydiphenyl sulfide, and the like. <Acid chlorides> 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, azelayl 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, etc. <Lactams> ε-caprolactam, ω-undecanelactam, ω-laurolactam, etc.

[0077] [Polyimide Resin] Examples of polyimide resins include, but are not limited to, reaction products of the diamines described above with the tetracarboxylic dianhydrides listed below. These may be used singly or in combination. Specific examples include polyimide compounds obtained by the method described in WO2023013224A1. <Tetracarboxylic Dianhydrides> 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2-dicarboxylic anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-hexafluoroisopropylidene ...4,4'-hexafluoroisopropylidenediphthalic anhydride, 5-(2,5-dioxotetrahydro-3- carboxylic 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 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(3,4-dicarboxyphenoxy)benzene dianhydride Bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenane Tetylenetetracarboxylic dianhydride, ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexa 4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) 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 Aqueous solutions, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic 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 anhydride, ethylene glycol-bis-(3,4-dicarboxylic anhydride phenyl) ether, 4,4'-biphenylbis(trimellitic acid monoester acid anhydride), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, etc.

[0078] [Allyl Compound] Examples of the allyl compound include monoallyl isocyanurate, diallyl isocyanurate, triallyl isocyanurate, etc. Specific examples include "TAIC" (manufactured by Mitsubishi Chemical Corporation), "MA-DGIC", and "DA-MGIC" (all manufactured by Shikoku Chemical Industry Co., Ltd.).

[0079] [Polybutadiene and Modified Products Thereof] Polybutadiene and modified products thereof are compounds having polybutadiene or 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 modified products thereof 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. Of 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 Chemical Industries, Ltd.) and 1,2-SBS (manufactured by Nippon Soda Co., Ltd.). Examples of polybutadienes 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 volatilization is high, making it difficult to adjust the solids content during prepreg production. Above the upper limit of the above range, compatibility with other curable resins deteriorates. In general, in the case of compounds containing heteroatoms such as oxygen and nitrogen, such as bismaleimides and polymaleimides, their polarity makes it difficult to ensure compatibility with low-polarity compounds, such as compounds composed mainly of hydrocarbons or compounds composed only of hydrocarbons. On the other hand, the compound of the present embodiment does not have a skeleton design in which heteroatoms such as oxygen and nitrogen are actively introduced, and therefore has excellent compatibility with materials having low polarity and low dielectric properties and compounds composed only of hydrocarbons.

[0080] [Polystyrene and modified products thereof] Polystyrene and modified products thereof 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 (registered trademark) 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.), and 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 block copolymer: Septon 8004, Septon 8006, Septon 8007L, all manufactured by Kuraray Co., Ltd.), SEEPS-OH (styrene-ethylene / ethylene-propylene-styrene block copolymer with a hydroxyl group at the end: Septon HG252, manufactured by Kuraray Co., Ltd.), SIS (styrene-isoprene-styrene block copolymer: Septon 5125, Septon 5127, all manufactured by Kuraray Co., Ltd.), hydrogenated SIS (hydrogenated styrene-isoprene-styrene block copolymer: Hybrar (registered trademark) 7125F, Hybrar 7311F) Examples of suitable polystyrenes include, but are not limited to, SIBS (styrene-isobutylene-styrene block copolymer: SIBSTAR (registered trademark) 073T, SIBSTAR 102T, SIBSTAR 103T (all manufactured by Kaneka Corporation), and Septon V9827 (manufactured by Kuraray Co., Ltd.). These may be used alone or in combination. Polystyrene and modified products thereof are preferably free of unsaturated bonds, as they have higher heat resistance and are less susceptible to oxidative degradation.Furthermore, there are no particular restrictions on the weight-average molecular weight of polystyrene and modified products thereof as long as it is 10,000 or more. However, if it is too large, compatibility with not only the polyphenylene ether compound but also low-molecular-weight components having a weight-average molecular weight of about 50 to 1,000 and oligomer components having 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.

[0081] [Polyethylene and Modified Polyethylenes] Polyethylene and modified polyethylenes are compounds having polyethylene or a polyethylene-derived structure in the molecule. Examples of polyethylene and modified polyethylenes 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 the polyphenylene ether compound but also low-molecular-weight components having a weight-average molecular weight of about 50 to 1,000 and oligomer components having 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.

[0082] [Benzoxazine Compound] Any benzoxazine compound may be used as long as it is a compound obtained by reacting a compound having a phenolic hydroxyl group, a compound having an amino group, or a compound having an aldehyde group. The compound having a phenolic hydroxyl group is not particularly limited, but for example, the above-mentioned phenolic resin, phenols (which may have a substituent such as an alkenyl group or an alkyl group), and bisphenols can be used. The compound having an amino group is not particularly limited, but the above-mentioned amine resin, diamine, and anilines (which may have a substituent such as an alkenyl group or an alkyl group) can be used. The aldehyde compound may be, for example, the above-mentioned aldehydes, but formaldehyde is preferably used. Commercially available benzoxazine compounds may be used, and examples thereof include benzoxazine P-d, Fa, and ALP-d (all manufactured by Shikoku Chemical Industry Co., Ltd.), JBZ-BA100N, JBZ-FA100N, JBZ-DP100N, JBZ-OP100N, JBZ-OP100D, and JBZ-OP100I (all manufactured by JFE Chemical Corporation), and BTBz (manufactured by Japan Material Technology Co., Ltd.).

[0083] [Flame Retardant] The curable resin composition of the present embodiment 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.

[0084] 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 an epoxy resin with the active hydrogen of the phosphanes; and red phosphorus. These may be used alone or in combination. Of the above-listed substances, phosphate esters, phosphanes, and phosphorus-containing epoxy compounds are preferred, with 1,3-phenylenebis(dixylilenyl phosphate), 1,4-phenylenebis(dixylilenyl phosphate), 4,4'-biphenyl(dixylilenyl phosphate), and phosphorus-containing epoxy compounds being particularly preferred.

[0085] The content of the flame retardant is preferably in the range of 0.1 to 0.6 parts by mass per 100 parts by mass of the curable resin composition. If the content is less than 0.1 part by mass, the flame retardancy may be insufficient, and if the content is more than 0.6 part by mass, the moisture absorption and dielectric properties of the cured product may be adversely affected.

[0086] [Polymerization Initiator] The curability of the curable resin composition of this embodiment can be improved by adding a polymerization initiator. The polymerization initiator is a compound capable of polymerizing an olefin functional group such as an ethylenically unsaturated bond, and examples thereof include an olefin metathesis polymerization initiator, an anionic polymerization initiator, a cationic polymerization initiator, and a radical polymerization initiator. Among these, it is preferable to use a radical polymerization initiator that has curability and appropriate stability. The radical polymerization initiator is a compound that generates radicals upon irradiation with ultraviolet light 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.

[0087] 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 (DCP) 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, and t-amylperoxy-2-ethylhexanoate. alkyl peresters such as di-2-ethylhexyl peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, t-butylperoxyisopropyl carbonate, 1,6-bis(t-butylperoxycarbonyloxy)hexane, t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyoctoate, lauroyl peroxide, etc. Specific examples include, but are not limited to, Irgacure OXE-04 and Irgacure 290 (both manufactured by BASF). Among the above organic peroxides, ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, peroxycarbonates, and the like are preferred, with dialkyl peroxides being more preferred.

[0088] 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.

[0089] The amount of polymerization initiator added is preferably 0.01 to 5 parts by mass, and particularly preferably 0.01 to 3 parts by mass, relative to 100 parts by mass of the curable resin composition. If the amount of polymerization initiator used is less than 0.01 part by mass, the molecular weight may not be sufficiently elongated during the polymerization reaction, while if it is more than 5 parts by mass, the dielectric properties such as the dielectric constant and dielectric loss tangent may be impaired.

[0090] [Polymerization inhibitor] The curable resin composition of the present embodiment may contain a polymerization inhibitor. By containing a polymerization inhibitor, storage stability is improved and the reaction initiation temperature can be controlled. Controlling the reaction initiation temperature makes it easier to ensure fluidity, does not impair impregnation into glass cloth or 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 in the lamination step are likely to occur.

[0091] The polymerization inhibitor may be added during or after the synthesis of the compound of this embodiment. The amount of the polymerization inhibitor used is 0.008 to 1 part by weight, preferably 0.01 to 0.5 parts by weight, based on 100 parts by weight of the compound of this embodiment.

[0092] Examples of the polymerization inhibitor include phenol-based, sulfur-based, phosphorus-based, hindered amine-based, nitroso-based, and nitroxyl radical-based. One type of polymerization inhibitor may be used alone, or multiple types may be used in combination. Among these, in this embodiment, phenol-based, hindered amine-based, nitroso-based, and nitroxyl radical-based inhibitors are preferred.

[0093] 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 polymerizable phenols include, but are not limited to, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-isocyanurate, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-s-triazine-2,4,6-(1H,3H,5H)trione, and tocopherol.

[0094] 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.

[0095] 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 bis(2,4-di-t-butylphenyl) phosphite, cyclic neopentane tetrayl bis(2,4-di-t-butyl-4-methylphenyl) phosphite, bis[2- phosphites such as t-butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl]hydrogen phosphite, and oxaphosphaphenanthrene oxides such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, but are not limited to these.

[0096] Examples of the hindered amine polymerization inhibitor include ADK STAB (registered trademark) LA-40MP, ADK STAB LA-40Si, ADK STAB LA-402AF, ADK STAB LA-87, ADK STAB LA-82, ADK STAB LA-81, ADK STAB LA-77Y, ADK STAB LA-77G, ADK STAB LA-72, ADK STAB LA-68, ADK STAB LA-63P, ADK STAB LA-57, and ADK STAB LA-52 (all manufactured by ADE Corporation). Examples of suitable fluororesin include, but are not limited to, Tinuvin (registered trademark), ...

[0097] Examples of the nitroso-based polymerization inhibitor include, but are not limited to, p-nitrosophenol, N-nitrosodiphenylamine, and the ammonium salt (cupferron) of N-nitrosophenylhydroxyamine. Of these, the ammonium salt (cupferron) of N-nitrosophenylhydroxyamine is preferred.

[0098] 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.

[0099] [Light Stabilizer] The curable resin composition of the present embodiment may contain a light stabilizer. As the light stabilizer, a hindered amine light stabilizer (Hindered Amine Light Stabilizers, HALS) or the like is suitable. Examples of HALS include a reaction product 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, a polycondensation product of dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine, and 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)]. Examples of suitable hydroxybenzyl compounds include, but are not limited to, 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, and bis(1,2,2,6,6-pentamethyl-4-piperidyl) 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate. These compounds may be used alone or in combination.

[0100] The content of the light stabilizer is preferably in the range of 0.001 to 0.1 parts by mass relative to 100 parts by mass of the curable resin composition. 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 moisture absorption and dielectric properties of the cured product may be adversely affected.

[0101] The curable resin composition of this embodiment can be obtained by uniformly mixing the above components. The curable resin composition of this embodiment can be easily cured using methods similar to those known in the art. For example, the curable resin composition of this embodiment can be obtained by thoroughly mixing an epoxy resin and a curing agent, as well as optionally a curing accelerator, an inorganic filler, a mold release agent, a silane coupling agent, and additives, using an extruder, kneader, roll, or the like, until uniform, and then molding the resulting mixture using a melt casting method, transfer molding method, injection molding method, compression molding, or the like, followed by heating at 80 to 200°C for 2 to 10 hours to obtain a cured product.

[0102] The curable resin composition of this embodiment may also contain a solvent, if necessary. The solvent-containing curable resin composition (epoxy resin varnish) is impregnated into a fibrous material (substrate) such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, or paper, and the resulting prepreg is heat-dried and then hot-press molded to produce a cured product of the curable resin composition of this embodiment. The solvent content of this curable resin composition is typically about 10 to 70% by mass, preferably about 15 to 70% by mass. Examples of the solvent include γ-butyrolactones; amide solvents such as N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and N,N-dimethylimidazolidinone; sulfones such as tetramethylene sulfone; ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and propylene glycol monobutyl ether, preferably mono- or di-lower (1 to 3 carbon atoms) alkyl ethers of lower (1 to 3 carbon atoms) alkylene glycols; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, preferably di-lower (1 to 3 carbon atoms) alkyl ketones in which the two alkyl groups may be the same or different; and aromatic solvents such as toluene and xylene. These may be used alone or in combination.

[0103] Alternatively, a sheet-like adhesive can be obtained by applying the epoxy resin varnish onto a release film, removing the solvent under heating, and then B-staging the varnish. This sheet-like adhesive can be used as an interlayer insulating layer in a multilayer substrate or the like.

[0104] The cured product obtained in this embodiment can be used in various applications, specifically, general applications in which thermosetting resins such as epoxy resins are used, such as adhesives, paints, coating agents, molding materials (including sheets, films, FRP, etc.), insulating materials (including printed circuit boards, electric wire coatings, etc.), sealants, and additives for other resins, etc.

[0105] Examples of adhesives include adhesives for civil engineering, construction, automobiles, general office use, and medical use, as well as adhesives for electronic materials. Among these, adhesives for electronic materials include interlayer adhesives for multilayer substrates such as build-up substrates, die bonding agents, semiconductor adhesives such as underfills, underfills for reinforcing BGAs, and mounting adhesives such as anisotropic conductive films (ACFs) and anisotropic conductive pastes (ACPs).

[0106] Examples of the sealant include potting, dipping, and transfer mold sealing for capacitors, transistors, diodes, light-emitting diodes, ICs, and LSIs; potting sealing for COB, COF, TAB, and the like for ICs and LSIs; underfill for flip chips; and sealing (including reinforcing underfill) when mounting IC packages such as QFP, BGA, and CSP.

[0107] The present invention will now be described in more detail with reference to examples. Unless otherwise specified, all parts are by weight. However, the present invention is not limited to these examples.

[0108] The various analytical methods used in the examples are described below. GPC (Gel Permeation Chromatography) Analysis Apparatus: DGU-20A, LC-20AD, SIL-20A, RID-20A, SPD-M40, CTO-20A, CBM-20A Column: SHODEX GPC KF-601 (2 columns), KF-602, KF-602.5, KF-603 Flow rate: 1.5 ml / min Column temperature: 40°C Solvent used: THF (tetrahydrofuran) Detector: RI (differential refractometer) ICI viscosity (150°C): Measured according to JIS K-7117-2 Softening point: Measured using a METTER TOLEDO softening point tester FP90. Epoxy equivalent: Measured by a method in accordance with JIS K-7236.

[0109] Example 1: While purging with nitrogen into a flask equipped with a thermometer, a condenser, and a stirrer, 311.6 parts of 3-methyl-6-t-butylphenol, 0.4 parts of 4-methyl-2-t-butylphenol, 122 parts of salicylaldehyde, 217 parts of methanol, and 5 parts of methanesulfonic acid were added, the temperature was raised to 60°C, and the reaction was carried out for 13 hours. The mixture was allowed to cool to room temperature, neutralized with 4.4 parts of a 48% aqueous sodium hydroxide solution, and the solvent was recovered under reduced pressure at 60°C to obtain a phenolic resin (P1) represented by the following formula (c-2) as a yellow powder. The GPC chart is shown in Figure 1 (the number average molecular weight Mn was 581, and the weight average molecular weight Mw was 601). The hydroxyl equivalent calculated from the GPC area % was 144 g / eq. (the yield was 417 parts, of which 7 g of salt was contained). The total area of ​​the peaks derived from the starting materials 3-methyl-6-t-butylphenol and 4-methyl-2-t-butylphenol was 0.5 area %, the area of ​​the peaks derived from the component of the compound represented by the following formula (c-2) where n = 1 was 91.6 area %, and the area of ​​the peaks derived from compounds higher in molecular weight than the compound represented by the following formula (c-2) where n = 1 was 7.9 area %.

[0110]

[0111] Example 2: While purging nitrogen into a flask equipped with a thermometer, a condenser, and a stirrer, 1305 parts of epichlorohydrin, 386 parts of dimethyl sulfoxide, and 23 parts of water were added to 407 parts of the phenolic resin (P1) obtained in Example 1, and the internal temperature was raised to 45°C. 114 parts of sodium hydroxide were added in portions over 3 hours, and the reaction was carried out at 45°C for 1.5 hours and at 70°C for 0.5 hours. The solvent and excess epichlorohydrin were distilled off under reduced pressure, and 1280 parts of methyl isobutyl ketone was added. After washing the organic layer with 670 parts of water, 25.3 parts of a 30 wt% aqueous sodium hydroxide solution, 26.9 parts of methanol, and 25 parts of water were added, and the reaction was carried out at 75°C for 1 hour. The organic layer was washed with water until the drainage was neutral, and the solvent was distilled off from the resulting solution under reduced pressure, yielding 525 parts of an epoxy resin (E1) represented by the following formula (d-2) as a yellow solid. The epoxy equivalent was 216 g / eq. The ICI viscosity at 150°C was 0.04 Pa s, and the softening point was 72.4°C. A GPC chart of the obtained epoxy resin (E1) is shown in Figure 2 (the number average molecular weight Mn was 593, and the weight average molecular weight Mw was 644). The total value of the peak areas derived from the raw materials, the reaction product of 3-methyl-6-t-butylphenol and epihalohydrin, and the reaction product of 4-methyl-2-t-butylphenol and epihalohydrin, was 0.3 area%, the peak area derived from the component of the compound represented by formula (d-2) below, where n = 1, was 86.0 area%, and the peak area derived from compounds higher in molecular weight than the compound represented by formula (d-2) below was 13.7 area%.

[0112]

[0113] Example 3 and Comparative Example 1 The epoxy resin (E1) obtained in Example 2, an epoxy resin represented by the following formula (e) (FAE-2500, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 216 g / eq., softening point 86°C, ICI viscosity at 150°C 0.29 Pa s), a phenol novolak resin (PN(H-1), manufactured by Meiwa Kasei Co., Ltd., softening point 85°C, hydroxyl equivalent 104 g / eq.) as a curing agent, and triphenylphosphine (hereinafter also referred to as TPP) as a curing accelerator were used, and were compounded in the proportions (parts by weight) shown in Table 1. The mixture was uniformly mixed and kneaded using a mixing roll, and after demolding, cured at 160°C for 2 hours and then at 180°C for 6 hours to obtain a test piece for evaluation.

[0114]

[0115] [Gel time] The time until gelation was measured on a hot plate heated to 175°C. [Heat resistance / glass transition temperature (Tg)] Measured using a dynamic viscoelasticity tester, the temperature at which tanδ reached its maximum value. Dynamic viscoelasticity measuring instrument: TA-instruments DMA-2980. Heating rate: 2°C / min. [5% weight loss temperature] Using a TG / DTA6200 (Hitachi High-Tech Science Corporation), measurements were made from 30°C to 300°C at a nitrogen gas flow rate of 200 mL / min and a heating rate of 10°C / min. [Flexural modulus] Measured in accordance with JIS K-6911 at 30°C. [Water absorption] The initial mass of a disc-shaped test piece measuring 5 cm in diameter and 4 mm in thickness was measured, and then the test piece was immersed in water at 100°C and held there for 24 hours. The mass was then measured, and the water absorption was calculated using the following formula: Water absorption rate (%) = (mass after 24 hours - initial mass) / mass after 24 hours

[0116]

[0117] The phenolic resin P1 and the epoxy resin E1 of the present invention were confirmed to have low ICI viscosity and high fluidity. Furthermore, the curable resin composition of Example 3 of the present invention was confirmed to have excellent fluidity in terms of its long gel time and the long period during which low viscosity can be maintained after melting. Furthermore, the cured product thereof was confirmed to have good heat resistance, as evidenced by a glass transition temperature of 200°C or higher, as well as excellent elastic modulus and low water absorption.

[0118] The epoxy resin of the present invention is suitable for use in electric and electronic parts such as semiconductor encapsulants, printed wiring boards, build-up laminates, and optical waveguide devices.

Claims

1. A phenolic resin obtained by reacting a compound represented by the following formula (a) with a compound represented by the following formula (b): (In formula (a), each R independently represents a hydrocarbon group having 1 to 5 carbon atoms. The total number of carbon atoms in the R is 2 to 8. k is an integer of 1 to 4.) 2. The phenolic resin according to claim 1, wherein the content of the compound represented by the following formula (c) is 75 to 95 area % as determined by differential refractometer detection in gel permeation chromatography: (In formula (c), each R independently represents a hydrocarbon group having 1 to 5 carbon atoms. In each benzene ring substituted with R, the total number of carbon atoms of the R is 2 to 8. k is an integer of 1 to 3.) 3. An epoxy resin obtained by reacting the phenolic resin according to claim 1 or 2 with epihalohydrin.

4. A curable resin composition containing the epoxy resin according to claim 3.

5. The curable resin composition according to claim 4, further comprising a curing agent and / or a curing accelerator.

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

7. A cured product obtained by curing the curable resin composition according to claim 4.

8. An epoxy resin represented by the following formula (d-1): (In formula (d-1), each R independently represents a hydrocarbon group having 1 to 5 carbon atoms. In each benzene ring substituted with R, the total number of carbon atoms of the R is 2 to 8. k is an integer of 1 to 3. n is the average number of repetitions and is 1 to 20.)