Curable resin composition, prepreg, and cured products thereof

Abstract

The present invention provides a curable resin composition which has high heat resistance and excellent ease of decomposition at high temperatures.　Provided is a curable resin composition containing an epoxy resin (A) represented by formula (1) and a phenol resin (B) represented by formula (2). The proportion of the integral value of aromatic carbon atoms to the integral value of all carbon atoms contained in the epoxy resin (A) and the phenol resin (B) in 13C-NMR analysis is 30-60%. (In formulae (1) and (2), the multiple R1 each independently represent a C1-5 alkyl group or an optionally substituted C1-20 aromatic group. The multiple R2 each independently represent a C1-5 alkyl group or an optionally substituted C1-20 aromatic group. The multiple p1 each independently represent an integer of 0-3. The multiple p2 each independently represent an integer of 0-3. G represents a substituted or unsubstituted glycidyl group. The multiple r1 each independently represent 1 or 2. The multiple r2 each independently represent 1 or 2. The multiple X each independently represent an optionally substituted C1-20 hydrocarbon group. The multiple Y each independently represent an optionally substituted C1-20 hydrocarbon group. n1 and n2 are the average number of repetitions, and 1<n1<5, 1<n2<5. )

Description

Curable resin compositions, prepregs, and cured products thereof

[0001] The present invention relates to curable resin compositions, prepregs, and cured products thereof, and is suitably used for lightweight, high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics.

[0002] Epoxy resins, when cured with various curing agents, become cured products with excellent mechanical, water-resistant, chemical-resistant, heat-resistant, and electrical properties, and are used in a wide range of fields such as adhesives, paints, laminates, molding materials, and casting materials. Carbon fiber reinforced composite materials (CFRP), in which epoxy resin and curing agents are impregnated into reinforcing fibers as a matrix resin and cured, can be given properties such as lightness and high strength, and in recent years have been widely used in aircraft structural components, wind turbine blades, automobile body panels, and computer applications such as IC trays and laptop casings (housings), and demand is increasing. In particular, taking advantage of the lightweight and high-strength properties of its molded products, it is used as a matrix resin for aircraft applications.

[0003] Improving the properties of CFRP depends not only on the grade and content of carbon fibers (CF), but also significantly on the role of the resin. In particular, heat resistance, impact resistance, and flame retardancy are strongly influenced by the resin. Therefore, epoxy resins used as the matrix resin in CFRP are required to have strong heat resistance, impact resistance, and flame retardancy (Non-Patent Literature 1).

[0004] On the other hand, CFRP is difficult to decompose, and its significant advantage of being flame-retardant means that incineration incurs enormous fuel costs. As a result, much of the product that has reached the end of its lifespan is currently landfilled as waste, raising concerns about the environmental impact.

[0005] Therefore, technological development for recycling carbon dioxide (CF) in CFRP is underway. Various recycling methods are being considered, one of which is the thermal decomposition method. In this method, the cured epoxy resin used in the matrix resin is thermally decomposed at a temperature of 400°C or higher, and the CF is reused. However, when conventional epoxy resins are used, 20-30% residual carbon remains on the fibers, making regeneration difficult. For this reason, epoxy resin compositions used as the matrix resin in CFRP are required to be easily thermally decomposable at high temperatures (Non-Patent Literature 2).

[0006] Hiroyuki Hirano, Network Polymers Vol. 36 No. 1, 2015. Toru Kamo, Journal of the Japan Society of Waste Management and Resource Recycling Vol. 29 No. 2, pp. 133-141, 2018.

[0007] International Publication No. 2021 / 193303

[0008] Patent Document 1 describes a resin composition of an epoxy resin having an alicyclic skeleton and a phenol novolac. However, the heat resistance of this resin composition is not sufficient to meet the requirements of recent years. Furthermore, conventional high-heat-resistant epoxy resin compositions incorporate many rigid and thermally decomposable aromatic rings into the skeleton, so their thermal decomposition properties at high temperatures are not sufficient for CFRP recycling.

[0009] Therefore, there is a need to obtain resin compositions and their cured products that are excellent in terms of high heat resistance and easy decomposition at high temperatures. The present invention has been made in view of the above points, and aims to provide a curable resin composition that is excellent in terms of high heat resistance and easy decomposition at high temperatures.

[0010] In other words, the present invention relates to the following [1] to [9]. In this application, "(numerical value 1) to (numerical value 2)" indicates that upper and lower limits are included. [1] A curable resin composition comprising an epoxy resin (A) represented by the following formula (1) and a phenolic resin (B) represented by the following formula (2), １３ A curable resin composition in which, in 1C-NMR analysis, the proportion of the integral value of aromatic carbon atoms among the integral values ​​of all carbon atoms contained in the epoxy resin (A) and the phenolic resin (B) is 30% or more and 60% or less.

[0011]

[0012] (In equations (1) and (2), there are multiple R １ Each of these independently represents an alkyl group having 1 to 5 carbon atoms, or an aromatic group having 1 to 20 carbon atoms, which may have substituents. There are multiple R's. ２ Each independently represents an alkyl group having 1 to 5 carbon atoms, or an aromatic group having 1 to 20 carbon atoms which may have substituents. Multiple p1s are each independently integers from 0 to 3. Multiple p2s are each independently integers from 0 to 3. G represents a substituted or unsubstituted glycidyl group. Multiple r1s are each independently 1 or 2. Multiple r2s are each independently 1 or 2. Multiple Xs are each independently representing a hydrocarbon group having 1 to 20 carbon atoms which may have substituents. Multiple Ys are each independently representing a hydrocarbon group having 1 to 20 carbon atoms which may have substituents. n1 and n2 are the average values ​​of the number of repetitions, where 1 < n1 < 5 and 1 < n2 < 5.) [2] The curable resin composition according to the preceding paragraph [1], wherein the epoxy resin (A) is represented by the following formula (3) or (4).

[0013]

[0014] (In equations (3) to (4), there are multiple R １ Each of these independently represents an alkyl group having 1 to 5 carbon atoms, or an aromatic group having 1 to 20 carbon atoms, which may have substituents. There are multiple R's. ３ Each of these independently represents an alkyl group having 1 to 5 carbon atoms, or an aromatic group having 1 to 20 carbon atoms, which may have substituents. There are multiple R's. ４Each independently represents an alkyl group having 1 to 5 carbon atoms or a hydrogen atom. When there are a plurality of p1, each independently is an integer of 0 to 3. When there are a plurality of p3, each independently is an integer of 0 to 3. G represents a substituted or unsubstituted glycidyl group. When there are a plurality of r1, each independently is 1 or 2. When there are a plurality of r5, each independently is 1 or 2. l1 is 0 or 1. n1 is the average value of the repeating number, and 1 < n1 < 5. ) [3] The curable resin composition according to the above [1] or [2], wherein the phenol resin (B) is represented by the following formula (5) or (6).

[0015]

[0016] (In the formulas (5) to (6), when there are a plurality of R ２ each independently represents an alkyl group having 1 to 5 carbon atoms or an aromatic group having 1 to 20 carbon atoms which may have a substituent. When there are a plurality of R ３２ each independently represents an alkyl group having 1 to 5 carbon atoms or an aromatic group having 1 to 20 carbon atoms which may have a substituent. When there are a plurality of R ４２Each of the p2s independently represents an alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. Each of the multiple p2s is an integer from 0 to 3. Each of the multiple p32s is an integer from 0 to 3. Each of the multiple r2s is independently 1 or 2. Each of the multiple r52s is independently 1 or 2. l2 is 0 or 1. n2 is the average value of the number of repetitions, where 1 < n2 < 5.) [4] The curable resin composition according to any one of the preceding paragraphs [1] to [3], further comprising a curing accelerator. [5] A curable resin composition according to any one of items [1] to [4] above, further comprising one or more selected from a polymerization initiator, an epoxy resin other than epoxy resin (A), an active ester compound, a phenolic resin other than phenolic resin (B), a polyphenylene ether compound, 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 a modified thereof, polystyrene and a modified thereof, polyethylene and a modified thereof, and a benzoxazine compound. [6] A cured product obtained by curing the curable resin composition according to any one of items [1] to [5] above. [7] A curable resin composition according to any one of items [1] to [5] above, for use in carbon fiber reinforced plastics. [8] A prepreg in which the curable resin composition for carbon fiber reinforced plastics according to item [7] above is held on a sheet-like fibrous substrate. [9] A cured product obtained by curing the prepreg according to item [8] above.

[0017] According to the present invention, it is possible to provide a curable resin composition and a cured product thereof that exhibit high heat resistance and excellent ease of decomposition at high temperatures.

[0018] This is the GPC chart of Synthesis Example 1. This is the HPLC chart of Synthesis Example 1. This is the GPC chart of Synthesis Example 2. This is the GPC chart of Synthesis Example 3. This is the HPLC chart of Synthesis Example 3. Example 1 １３ This is a C-NMR chart. Example 2 １３ This is a C-NMR chart. Example 3 １３ This is a C-NMR chart. Comparative Example 1 １３ This is a C-NMR chart. Comparative Example 2１３ This is a C-NMR chart.

[0019] The embodiments of the present invention (hereinafter also referred to as "this embodiment") will be described in more detail below.

[0020] The curable resin composition of this embodiment is a curable resin composition containing an epoxy resin (A) represented by the following formula (1) and a phenolic resin (B) represented by the following formula (2).

[0021]

[0022] In equations (1) and (2), there are multiple R's. １ Each of these independently represents an alkyl group having 1 to 5 carbon atoms, or an aromatic group having 1 to 20 carbon atoms, which may have substituents, and preferably an alkyl group having 1 to 5 carbon atoms. Multiple R groups exist. ２ Each independently represents an alkyl group having 1 to 5 carbon atoms, or an aromatic group having 1 to 20 carbon atoms that may have substituents, preferably an alkyl group having 1 to 5 carbon atoms. Each of the multiple p1s is an integer from 0 to 3, preferably 0 or 1, and more preferably 0. Each of the multiple p2s is an integer from 0 to 3, preferably 0 or 1, and more preferably 0. G represents a substituted or unsubstituted glycidyl group, preferably an unsubstituted glycidyl group. Each of the multiple r1s is independently 1 or 2. Each of the multiple r2s is independently 1 or 2. Each of the multiple Xs represents a hydrocarbon group having 1 to 20 carbon atoms that may have substituents. Each of the multiple Ys represents a hydrocarbon group having 1 to 20 carbon atoms that may have substituents. n1 and n2 are the average values ​​of the number of repetitions, 1 < n1 < 5 and 1 < n2 < 5.

[0023] The values ​​of n1 and n2 can be calculated from the number-average molecular weight obtained by gel permeation chromatography (GPC, detector: RI) of epoxy resin (A) or phenolic resin (B), or from the area ratio of the separated peaks.

[0024] By controlling r1 and r2 of the epoxy resin (A) and the phenolic resin (B), the crosslink density of the cured product can be adjusted to obtain a cured product having excellent heat resistance and mechanical properties.

[0025] The curable resin composition of the present embodiment １３ In the C-NMR analysis, it is preferable that the ratio of the integrated value of aromatic carbon atoms among the integrated values of all carbon atoms contained in the epoxy resin (A) and the phenolic resin (B) is 30% or more and 60% or less, more preferably 40% or more and 55% or less, and particularly preferably 45% or more and 53% or less. When it is larger than 60%, the cured product may become extremely rigid and there is a risk of losing the heat decomposability at high temperatures. On the other hand, when it is less than 40%, the heat resistance of the cured product may decrease. In the present embodiment, １３ C-NMR is measured under the following conditions, and the peak in the high magnetic field region of 100 ppm or more is calculated as aliphatic carbon atoms, and the peak in the low magnetic field region of less than 100 ppm is calculated as aromatic carbon atoms.

[0026] ・ １３ C-NMR (nuclear magnetic resonance) analysis Manufacturer: NEC Corporation Apparatus: JNM-ECS400 Number of integrations: 16384 Relaxation time: 2 seconds Solvent used: Aceton-d6 Measurement temperature: room temperature

[0027] [Epoxy resin (A)] The softening point of the epoxy resin (A) is preferably 40°C to 100°C, more preferably 50°C to 90°C, and still more preferably 55°C to 90°C. If the softening point is less than 40°C, there is a risk that solvents or the like remain, and there may be problems such as poor curing and voids during molding. On the other hand, if the softening point exceeds 100°C, the handling property during kneading with other resins may deteriorate.

[0028] The melt viscosity of the epoxy resin (A) is preferably 0.05 Pa·s or more and 3.0 Pa·s or less (ICI melt viscosity (150°C) cone plate method), and more preferably 0.1 Pa·s or more and 2.0 Pa·s or less. When the viscosity is 0.05 Pa·s or more, the solubility in solvents becomes good. Conversely, when the melt viscosity is 3.0 Pa·s or less, the handling property during kneading with other resins becomes good.

[0029] The epoxy equivalent of the epoxy resin (A) is preferably 140 to 250 g / eq., more preferably 160 to 230 g / eq., and particularly preferably 180 to 220 g / eq. If it is less than 140 g / eq., the cured product may become extremely rigid, leading to a decrease in the flexibility of the cured product and a decrease in the thermal decomposition resistance at high temperatures. On the other hand, if it is greater than 250 g / eq., the crosslinking density may decrease, resulting in a decrease in heat resistance.

[0030] As the epoxy resin (A), an epoxy resin represented by the following formula (3) or (4) is preferred.

[0031]

[0032] In formulas (3) to (4), G, R １ , p1, r1, and n1 have the same meanings as in the above formula (1). When there are multiple Rs ３ , each independently represents an alkyl group having 1 to 5 carbon atoms or an aromatic group having 1 to 20 carbon atoms which may have a substituent, preferably an alkyl group having 1 to 5 carbon atoms. When there are multiple Rs ４ , each independently represents an alkyl group having 1 to 5 carbon atoms or a hydrogen atom. When there are multiple p3s, each independently is an integer of 0 to 3, preferably 0 or 1, and more preferably 0. When there are multiple r5s, each independently is 1 or 2. l1 is 0 or 1.

[0033] In the epoxy resin represented by the above formula (3), it is preferable that r1 be either 1 or 2. When r1 is only 1, excellent mechanical strength is exhibited, but the low crosslinking density may result in poor heat resistance. On the other hand, when r1 is only 2, i.e., when the functional group density is increased, heat resistance improves, but the increased crosslinking density makes it hard and brittle, thus reducing mechanical strength, and there is a risk that the water absorption rate will increase significantly. The increased water absorption rate may lead to adverse effects such as a significant decrease in strength after absorbing moisture. This is because the properties deteriorate due to the polarity of the functional groups when the functional group density becomes too high, and because the functional groups are close together, they may not react properly, leaving some unreacted, or crosslinking occurs within the molecule, which may result in problems such as not improving heat resistance much.

[0034] In the epoxy resin represented by the above formula (3), in the total amount of epoxy resin where l1=0, n1=1, and p1=0, the proportion of the component in which one of r1 is 1 and the other is 2 is preferably 1 area% or more and less than 70 area% in terms of HPLC area percentage, more preferably 5 area% or more and less than 50 area%, and particularly preferably 10 area% or more and less than 40 area%. A proportion of less than 70 area% results in a high modulus of elasticity, and a proportion of 1 area% or more results in good heat resistance.

[0035] [Phenolic Resin (B)] The preferred range for the hydroxyl group equivalent of phenolic resin (B) is 60 g / eq. or more and less than 180 g / eq., and more preferably 80 g / eq. or more and less than 160 g / eq. If the hydroxyl group equivalent is less than 60 g / eq., i.e., if the concentration of hydroxyl groups in the phenolic resin is high, the crosslinking density increases, making it hard and brittle and leading to a decrease in mechanical strength, which is undesirable. If the hydroxyl group equivalent is greater than 180 g / eq., the heat resistance of the cured product decreases, which is undesirable. When the hydroxyl group equivalent is appropriate, the heat resistance of the cured product can be improved without causing a decrease in mechanical strength.

[0036] The preferred softening point range for phenolic resin (B) is 80 to 140°C, and more preferably 100 to 130°C. When the softening point is within this range, the resins do not block each other at room temperature, resulting in excellent handling properties.

[0037] As the phenolic resin (B), a phenolic resin represented by the following formula (5) or (6) is preferred.

[0038]

[0039] In formulas (5) to (6), R ２ p2, r2, and n2 have the same meaning as in equation (2) above. Multiple R ３２ Each of these independently represents an alkyl group having 1 to 5 carbon atoms, or an aromatic group having 1 to 20 carbon atoms, which may have substituents, and preferably an alkyl group having 1 to 5 carbon atoms. Multiple R groups exist. ４２ Each of the multiple p32s independently represents an alkyl group having 1 to 5 carbon atoms, or a hydrogen atom. Each of the multiple p32s independently represents an integer from 0 to 3, preferably 0 or 1, and more preferably 0. Each of the multiple r52s independently represents 1 or 2. l2 is 0 or 1.

[0040] In the phenolic resin represented by the above formula (5), it is preferable that r2 be either 1 or 2. When r2 is only 1, excellent mechanical strength is exhibited, but the low crosslink density may result in poor heat resistance. On the other hand, when r2 is only 2, i.e., when the functional group density is increased, heat resistance improves, but the increased crosslink density makes it hard and brittle, thus reducing mechanical strength, and there is a risk that the water absorption rate will increase significantly. The increased water absorption rate may lead to adverse effects such as a significant decrease in strength after absorbing moisture. This is because the properties deteriorate due to the polarity of the functional groups when the functional group density becomes too high, and because the functional groups are close together, they may not react properly, leaving some unreacted, or crosslinking occurs within the molecule, which may result in problems such as not improving heat resistance much.

[0041] In the phenolic resin represented by the above formula (5), in the total amount of phenolic resin where l2=0, n2=1, and p2=0, the proportion of the component in which one of r2 is 1 and the other is 2 is preferably 1 area% or more and less than 70 area% in terms of HPLC area percentage, more preferably 5 area% or more and less than 50 area%, and particularly preferably 10 area% or more and less than 30 area%. A proportion of less than 70 area% results in a high modulus of elasticity, and a proportion of 1 area% or more results in good heat resistance, which is preferable.

[0042] [Method for producing phenolic resin (B)] The method for producing phenolic resin (B) is not limited, but examples include various aldehydes (formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.), various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, di Examples of reactions (condensation) include the reaction (condensation) of phenols with phenols (e.g., isopropenylbiphenyl, butadiene, isoprene), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone), aromatic dimethanols (benzenedimethanol, biphenyldimethanol, etc.), aromatic dichloromethyls (α,α'-dichloroxylene, bischloromethylbiphenyl, etc.), and aromatic bisalkoxymethyls (bismethoxymethylbenzene, bismethoxymethylbiphenyl, bisphenoxymethylbiphenyl, etc.). These can be used individually or in combination of two or more. When reacting (condensing) dicyclopentadiene with phenols, the amount of phenol is preferably in the range of 3 to 20 moles, and particularly preferably 5 to 10 moles, per mole of dicyclopentadiene.

[0043] Examples of phenols include catechol, resorcinol, and hydroquinone, which may have substituents as disubstituted phenols, and phenols which may have substituents as monosubstituted phenols. These may be used individually or in combination of two or more types.

[0044] In the above condensation reaction, it is preferable to use an acid catalyst. Preferred acid catalysts include Lewis acids such as boron trifluoride, anhydrous aluminum chloride, zinc chloride, sulfuric acid, and titanium chloride, and particularly preferred are ether complexes and phenol complexes of the above Lewis acids. These acid catalysts may be used individually or in combination of two or more types.

[0045] The amount of these acid catalysts used is not particularly limited, but can be selected in the range of 0.001 to 0.1 moles relative to the amount of dicyclopentadiene used. Furthermore, when adding these acid catalysts to the reaction system, they can be added gradually by pre-adding them to the heated molten phenols or by diluting them in a suitable solvent.

[0046] These condensation reactions in the presence of acid catalysts are preferably carried out in the range of 40 to 180°C, particularly preferably in the range of 80 to 165°C, and the reaction time can usually be selected in the range of 0.5 to 10 hours. These reactions can also be carried out in the presence of solvents that are inert to the reaction, such as nitrobenzene, diphenyl ether, dichlorobenzene, and carbon disulfide. Furthermore, the reactants thus obtained are neutralized to make the system neutral, or washed repeatedly with water in the presence of a solvent, then the water is separated and drained, and the solvent and unreacted materials are removed under heating and reduced pressure to obtain phenolic resin (B).

[0047] [Method for producing epoxy resin (A)] The method for producing epoxy resin (A) is not limited, but it can be obtained, for example, by the reaction of phenol resin (B) with epihalohydrin.

[0048] The epihalohydrins mentioned above are readily available on the market. The amount of epihalohydrin used is typically 4.0 to 10 moles, preferably 4.5 to 8.0 moles, and more preferably 5.0 to 7.0 moles, per mole of hydroxyl groups in the raw material phenol mixture. During epoxidation, the generated epoxy resin reacts with the unreacted phenolic hydroxyl groups to produce an epoxy resin having glycerin ether moieties. A higher amount of glycerin ether moieties is preferable because it increases the toughness of the cured epoxy resin. On the other hand, a high amount of glycerin ether moieties is undesirable because it increases the melt viscosity due to the increased molecular weight of the epoxy resin, leading to decreased handling properties and increased water absorption of the cured epoxy resin. Therefore, it is necessary to use an amount of epihalohydrin appropriate to the design. Using an excess of epihalohydrin relative to the hydroxyl groups of the raw material phenol resin is preferable because it can suppress intermolecular reactions during epoxidation and yield a low-viscosity epoxy resin.

[0049] In the above reaction, an alkali metal hydroxide can be used as a catalyst to accelerate the epoxidation step. Examples of alkali metal hydroxides that can be used include sodium hydroxide and potassium hydroxide. Solid materials or aqueous solutions thereof may be used, but in this embodiment, the use of solid materials molded into flakes is particularly preferred in terms of solubility and handling. The amount of alkali metal hydroxide used is usually 0.90 to 1.5 moles per mole of hydroxyl groups in the raw material phenol mixture, preferably 0.95 to 1.25 moles, and more preferably 0.99 to 1.15 moles.

[0050] Furthermore, quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, and trimethylbenzylammonium chloride may be added as catalysts to accelerate the reaction. The amount of quaternary ammonium salt used is usually 0.1 to 15 g, preferably 0.2 to 10 g, per mole of hydroxyl groups in the raw material phenol mixture.

[0051] The reaction temperature is usually 30 to 90°C, preferably 35 to 80°C. In this embodiment in particular, a temperature of 50°C or higher is preferred for higher purity epoxidation, and a temperature of 60°C or higher is particularly preferred. The reaction time is usually 0.5 to 10 hours, preferably 1 to 8 hours, and particularly preferably 1 to 3 hours. A reaction time that is too short is undesirable because the reaction will not proceed completely, and a reaction time that is too long is undesirable because byproducts will be formed. After washing the reactants of these epoxidation reactions with water, or without washing with water, the epihalohydrin and solvents are removed by heating under reduced pressure. Furthermore, in order to obtain an epoxy resin with even fewer hydrolyzable halogens, the recovered epoxy resin can be dissolved in a ketone compound having 4 to 7 carbon atoms (for example, methyl isobutyl ketone, methyl ethyl ketone, cyclopentanone, cyclohexanone, etc.) as a solvent, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to carry out the reaction and ensure ring closure. In this case, the amount of alkali metal hydroxide used is usually 0.01 to 0.3 moles, preferably 0.05 to 0.2 moles, per mole of hydroxyl groups in the raw material phenol mixture used for epoxidation. The reaction temperature is usually 50 to 120°C, and the reaction time is usually 0.5 to 2 hours.

[0052] After the reaction is complete, the generated salt is removed by filtration, washing with water, etc., and the solvent is further removed by distillation under reduced pressure and heating to obtain epoxy resin (A).

[0053] In the curable resin composition of this embodiment, the amount of curing agent used is preferably 0.7 to 1.2 equivalents per equivalent of epoxy groups in the epoxy resin. If the amount is less than 0.7 equivalents or more than 1.2 equivalents per equivalent of epoxy groups, curing may be incomplete, and good cured properties may not be obtained.

[0054] [Curing Accelerator] The curable resin composition of this embodiment can also have its curability improved by adding a curing accelerator. The gelation time can also be adjusted by using a curing accelerator. Preferred curing accelerators include anionic curing accelerators that promote the curing reaction by generating anions upon irradiation with ultraviolet light or visible light or by heating, cationic curing accelerators that promote the curing reaction by generating cations upon irradiation with ultraviolet light or visible light or by heating, and phosphines such as triphenylphosphine.

[0055] Examples of anionic curing accelerators other than the imidazole compounds mentioned above include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene, with 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene being preferred. Other examples include phosphines such as triphenylphosphine, tetrabutylammonium salts, triisopropylmethylammonium salts, trimethyldecanylammonium salts, cetyltrimethylammonium salts, and quaternary ammonium salts such as hexadecyltrimethylammonium hydroxide, but are not limited to these. Furthermore, these may be used individually or in combination of multiple types.

[0056] Examples of cationic curing accelerators include quaternary phosphonium salts such as triphenylbenzylphosphonium salt, triphenylethylphosphonium salt, and tetrabutylphosphonium salt (the counterions of the quaternary salts are halogens, organic acid ions, hydroxide ions, etc., with no particular preference, but organic acid ions and hydroxide ions are particularly preferred), cobalt naphthenate, copper naphthenate, lead acetylacetonate, copper acetylacetonate, dibutyltin maleate, manganese naphthenate, tin octoate, zinc carboxylates (zinc 2-ethylhexanoate, zinc stearate, zinc behenate, zinc myristate), and transition metal compounds (transition metal salts) such as zinc phosphate esters (zinc octyl phosphate, zinc stearyl phosphate), but are not limited to these. Furthermore, these may be used individually or in combination of multiple types.

[0057] In the curable resin composition of this embodiment, the amount of curing accelerator used is 0.01 to 5.0 parts by mass, depending on the total amount of epoxy resin (A) and phenolic resin (B) being 100 parts by mass.

[0058] [Inorganic Filler] The curable resin composition of this embodiment may contain an inorganic filler. Examples of inorganic fillers include, but are not limited to, powders such as fused silica, crystalline silica, porous silica, alumina, zircon, calcium silicate, calcium carbonate, quartz powder, silicon carbide, silicon nitride, boron nitride, zirconia, aluminum nitride, graphite, forsterite, steatite, spinel, mullite, titania, talc, clay, iron oxide, asbestos, and glass powder, or inorganic fillers made by shaping these into spheres or crushed forms. Furthermore, these may be used individually or in combination of multiple types.

[0059] When obtaining a curable resin composition for semiconductor encapsulation using an inorganic filler, the amount used is preferably 80 to 92 parts by mass, and more preferably 83 to 90 parts by mass, per 100 parts by mass of the curable resin composition. Furthermore, when obtaining a curable resin composition for interlayer insulating layer forming materials, copper-clad laminates, prepregs, RCCs, and other substrate materials, the amount used of the above-mentioned inorganic filler is preferably 5 to 80 parts by mass, and more preferably 10 to 60 parts by mass, per 100 parts by mass of the curable resin composition.

[0060] [Polymerization Initiator] The curable resin composition of this embodiment can also have its curability improved by adding a polymerization initiator. A polymerization initiator is a compound capable of polymerizing olefin functional groups such as ethylenically unsaturated bonds, and examples include olefin metathesis polymerization initiators, anionic polymerization initiators, cationic polymerization initiators, and radical polymerization initiators. Among these, it is preferable to use a radical polymerization initiator that has curability and appropriate stability. A radical polymerization initiator is a compound that generates radicals by irradiation with ultraviolet light or visible light or by heating, and initiates a chain polymerization reaction. Examples of radical polymerization initiators that can be used include organic peroxides, azo compounds, and benzopinacols, and it is preferable to use organic peroxides because they have little effect on curing temperature control, outgassing suppression, and the electrical properties of decomposition products.

[0061] Examples of the above organic peroxides include ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide, diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as dicumyl peroxide and 1,3-bis(t-butylperoxyisopropyl)benzene, peroxyketals such as t-butyl peroxybenzoate and 1,1-di-t-butylperoxycyclohexane, α-cumyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, t-amyl peroxy-2-ethylhexanoate, and t-butyl peroxy Examples of alkyl peresters such as oxy-2-ethylhexanoate, t-amyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxy-3,5,5-trimethylhexanoate, and t-amyl peroxybenzoate; peroxycarbonates such as di-2-ethylhexyl peroxydicarbonate, bis(4-t-butylcyclohexyl) peroxydicarbonate, t-butyl peroxyisopropyl carbonate, and 1,6-bis(t-butyl peroxycarbonyloxy)hexane; t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyoctoate, and lauroyl peroxide are examples, but are not limited to these. Furthermore, these may be used individually or in combination of multiple types. Among the above organic peroxides, ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, and peroxycarbonates are preferred, with dialkyl peroxides being more preferred.

[0062] Examples of the above-mentioned azo compounds include, but are not limited to, azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), and 2,2'-azobis(2,4-dimethylvaleronitrile). Furthermore, these compounds may be used individually or in combination.

[0063] 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, per 100 parts by mass of the curable resin composition. If the amount of polymerization initiator used is less than 0.01 parts by mass, the molecular weight may not elongate sufficiently during the polymerization reaction, and if it is more than 5 parts by mass, it may impair low dielectric properties such as dielectric constant and dielectric loss tangent.

[0064] [Polymerization Inhibitor] The curable resin composition of this embodiment may contain a polymerization inhibitor. Including a polymerization inhibitor improves storage stability and allows control of the reaction initiation temperature. Controlling the reaction initiation temperature makes it easier to ensure fluidity, prevents impregnation into glass cloth and the like, and facilitates B-stage production such as prepreg formation. If the polymerization reaction proceeds too far during prepreg formation, problems such as difficulty in lamination during the lamination process are likely to occur.

[0065] The amount of polymerization inhibitor used is preferably 0.008 to 1 part by mass, and more preferably 0.01 to 0.5 parts by mass, when the total amount of epoxy resin (A) and phenolic resin (B) is 100 parts by mass.

[0066] Examples of polymerization inhibitors include phenol-based, sulfur-based, phosphorus-based, hindered amine-based, nitroso-based, and nitroxyl radical-based agents. Furthermore, polymerization inhibitors may be used individually or in combination of multiple types. Of these, phenol-based, hindered amine-based, nitroso-based, and nitroxyl radical-based agents are preferred in this invention.

[0067] Examples of the above phenolic polymerization inhibitors include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-p-ethylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, and 2,4-bis[(octylthio)methyl]-o-c Monophenols such as resols, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] N,N'-Hexamethylenebis(3,5-di-t-butyl-4-hydroxyhydrocinnamamide), 2,2-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- Bisphenols such as calcium trimethyl-4-hydroxybenzylsulfonate ethyl, 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 include, but are not limited to, high molecular weight phenols such as 5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-s-triazine 2,4,6-(1H,3H,5H)trione, and tocopherol.

[0068] Examples of sulfur-based polymerization inhibitors include, but are not limited to, dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, and distearyl-3,3'-thiodipropionate.

[0069] Examples of the phosphorus polymerization inhibitors mentioned above include triphenyl phosphite, diphenylisodecyl phosphite, phenyldiisodecyl phosphite, tris(nonylphenyl) phosphite, diisodecylpentaerythritol phosphite, tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis(octadecyl) phosphite, cyclic neopentanetetraylbis(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis(2,4-di-t-butyl-4-methylphenyl) phosphite, and bis[2- Examples include, but are not limited to, phosphites such as t-butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl]hydrogen phosphite, 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.

[0070] Examples of the above hindered amine polymerization inhibitors include Adekastab LA-40MP, Adekastab LA-40Si, Adekastab LA-402AF, Adekastab LA-87, Adekastab LA-82, Adekastab LA-81, Adekastab LA-77Y, Adekastab LA-77G, Adekastab LA-72, Adekastab LA-68, Adekastab LA-63P, Adekastab LA-57, Adekastab Examples include, but are not limited to, LA-52, Chimassorb2020FDL, Chimassorb944FDL, Chimassorb944LD, Tinuvin622SF, TinuvinPA144, Tinuvin765, Tinuvin770DF, TinuvinXT55FB, Tinuvin111FDL, Tinuvin783FDL, Tinuvin791FB, etc.

[0071] Examples of the nitroso polymerization inhibitors mentioned above include, but are not limited to, p-nitrosophenol, N-nitrosodiphenylamine, and ammonium salts of N-nitrosophenylhydroxyamine (cuperone). Of these, ammonium salts of N-nitrosophenylhydroxyamine (cuperone) are preferred.

[0072] Examples of the above-mentioned nitroxyl radical polymerization inhibitors include, but are not limited to, di-tert-butylnitroxide, 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.

[0073] [Flame Retardant] The curable resin composition of this embodiment may contain a flame retardant. Examples of flame retardants include halogen-based flame retardants, inorganic flame retardants (antimony compounds, metal hydroxides, nitrogen compounds, boron compounds, etc.), and phosphorus-based flame retardants, but phosphorus-based flame retardants are preferred from the viewpoint of achieving halogen-free flame retardancy. The phosphorus-based flame retardant may be either reactive or additive type. Specific examples include phosphate esters such as trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixyllenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixyllenyl phosphate, 1,3-phenylenebis(dixyllenyl phosphate), 1,4-phenylenebis(dixyllenyl phosphate), and 4,4'-biphenyl(dixyllenyl phosphate); phosphanes such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; phosphorus-containing epoxy compounds obtained by reacting epoxy resin with the active hydrogen of the above phosphanes; and red phosphorus, but are not limited to these. Furthermore, these may be used individually or in combination of multiple types. Of the above example substances, phosphate esters, phosphans, or phosphorus-containing epoxy compounds are preferred, and 1,3-phenylenebis(dixyllenyl phosphate), 1,4-phenylenebis(dixyllenyl phosphate), 4,4'-biphenyl(dixyllenyl phosphate), or phosphorus-containing epoxy compounds are particularly preferred.

[0074] The flame retardant content is preferably in the range of 0.1 to 0.6 parts by mass, when the total amount of epoxy resin (A) and phenolic resin (B) is 100 parts by mass. If the amount is less than 0.1 parts by mass, the flame retardancy may be insufficient, and if it is more than 0.6 parts by mass, it may adversely affect the low hygroscopicity and low dielectric properties of the cured product.

[0075] [Light stabilizer] The curable resin composition of this embodiment may also contain a light stabilizer. A hindered amine-based light stabilizer, particularly HALS, is preferred as the light stabilizer. Examples of HALS include the 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, the reaction 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 include, but are not limited to, bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(1-octyroxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate bis(1,2,2,6,6-pentamethyl-4-piperidyl). Furthermore, these may be used individually or in combination of multiple types.

[0076] The amount of light stabilizer is preferably in the range of 0.001 to 0.1 parts by mass, when the total amount of epoxy resin (A) and phenolic resin (B) is 100 parts by mass. If the amount is less than 0.001 parts by mass, it may be insufficient to exhibit the light stabilization effect, and if it is more than 0.1 parts by mass, it may adversely affect the low hygroscopicity and low dielectric properties of the cured product.

[0077] [Binder Resin] The curable resin composition of this embodiment may also use a binder resin. Examples of binder resins include butyral resins, acetal resins, acrylic resins, epoxy-nylon resins, NBR-phenolic resins, epoxy-NBR resins, silicone resins, etc., but are not limited to these. Furthermore, these may be used individually or in combination of multiple types.

[0078] The amount of binder resin added is preferably within a range that does not impair the flame retardancy and heat resistance of the cured product. When the total amount of epoxy resin (A) and phenolic resin (B) is 100 parts by mass, the amount is preferably 0.05 to 50 parts by mass, and more preferably 0.05 to 20 parts by mass is used as needed.

[0079] [Additives] The curable resin composition of this embodiment may also contain additives. Examples of additives include modified acrylonitrile copolymers, polyethylene, fluororesins, silicone gels, silicone oils, surface treatment agents for fillers such as silane coupling agents, mold release agents, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

[0080] The amount of additive added is preferably 1 part by mass or less, more preferably 0.7 parts by mass or less, per 100 parts by mass of the curable resin composition.

[0081] The curable resin composition of this embodiment may further contain epoxy resins other than epoxy resin (A), active ester compounds, phenolic resins other than phenolic resin (B), polyphenylene ether compounds, compounds having ethylenically unsaturated bonds, cyanate ester resins, isocyanate resins, polyamide resins, polyimide resins, polybutadiene and its modified counterparts, polystyrene and its modified counterparts, polyethylene and its modified counterparts, and benzoxazine compounds. These may be used individually or in combination of multiple compounds. Among these compounds, it is preferable to include epoxy resins, compounds having ethylenically unsaturated bonds, cyanate ester resins, polyphenylene ether compounds, polybutadiene and its modified counterparts, polystyrene and its modified counterparts, and polyethylene and its modified counterparts, based on a balance of heat resistance, adhesion, and dielectric properties. By including these compounds, the brittleness of the cured product can be improved and adhesion to metals can be enhanced, and cracks in the package can be suppressed during reliability tests such as solder reflow and thermal cycling. Unless otherwise specified, the amount of the above-mentioned compound used is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and most preferably 3 parts by mass or less, relative to the total amount of epoxy resin (A) and phenolic resin (B). Furthermore, the preferred lower limit is 0.1 parts by mass or more, more preferably 0.25 parts by mass or more, and even more preferably 0.5 parts by mass or more. Within this range, the properties of the epoxy resin and phenolic resin can be utilized while adding the effects of each compound. Examples of these components can be used as shown below.

[0082] [Epoxy Resin] In the curable resin composition of this embodiment, epoxy resins other than epoxy resin (A) may be blended. Preferred epoxy resins are exemplified below, but are not limited to these. The epoxy resin may be liquid or solid, and may be used alone or in combination of multiple types.

[0083] Examples of liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, and epoxy resin having a butadiene structure. Specific examples include "RE310S", "RE410S" (both manufactured by Nippon Kayaku Co., Ltd., bisphenol A type epoxy resin), "RE303S", "RE304S", "RE403S", "RE404S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy resin), "HP4032", "HP4032D", "HP4032SS" (all manufactured by DIC Corporation, naphthalene type epoxy resin), "828US", "jER828EL", "825", "828EL" (all manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin), "jE807", "1750" (both manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin), and "jER152" (manufactured by Mitsubishi Chemical Corporation, phenol Examples include novolac-type epoxy resin, "630", "630LSD" (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), "Celoxide 2021P" (manufactured by Daicel Corporation, alicyclic epoxy resin with an ester skeleton), "PB-3600" (manufactured by Daicel Corporation, epoxy resin with a butadiene structure), "ZX1658", "ZX1658GS" (both manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., liquid 1,4-glycidylcyclohexane-type epoxy resin). These may be used individually or in combination of two or more types.

[0084] Preferred solid epoxy resins include, for example, bixylenol-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type tetrafunctional epoxy resin, cresol novolac-type epoxy resin, dicyclopentadiene-type epoxy resin, trisphenol-type epoxy resin, naphthol-type epoxy resin, biphenyl-type epoxy resin, naphthylene ether-type epoxy resin, anthracene-type epoxy resin, bisphenol A-type epoxy resin, bisphenol AF-type epoxy resin, and tetraphenylethane-type epoxy resin.Specific examples include "HP4032H" (manufactured by DIC Corporation, naphthalene-type epoxy resin), "HP-4700", "HP-4710" (both manufactured by DIC Corporation, naphthalene-type tetrafunctional epoxy resins), "N-690" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), "N-695" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (both manufactured by DIC Corporation, dicyclopentadiene-type epoxy resins), "EXA-7311", and "EXA-7311-G3". "EXA-7311-G4", "EXA-7311-G4S", "HP-6000" (all manufactured by DIC Corporation, naphthylene ether type epoxy resin), "EPPN-502H" (manufactured by Nippon Kayaku Co., Ltd., trisphenol type epoxy resin), "NC-7000L", "NC-7300" (both manufactured by Nippon Kayaku Co., Ltd., naphthol-cresol novolac type epoxy resin), "NC-3000H", "NC-3000", "NC-3000L", "NC-3100" (all manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin), "XD-1 "000-2L", "XD-1000-L", "XD-1000-H", "XD-1000-H" (all manufactured by Nippon Kayaku Co., Ltd., dicyclopentadiene type epoxy resin), "ESN475V" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., naphthol type epoxy resin), "ESN485" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., naphthol novolac type epoxy resin), "YX-4000H", "YX-4000", "YL6121" (all manufactured by Mitsubishi Chemical Corporation, biphenyl type epoxy resin), "YX-4000HK" (manufactured by Mitsubishi Chemical Corporation, bixylenol type epoxy resin) Examples include, "YX-8800" (manufactured by Mitsubishi Chemical Corporation, anthracene-type epoxy resin), "PG-100", "CG-500" (manufactured by Osaka Gas Chemical Co., Ltd., fluorene-type epoxy resin), "YL-7760" (manufactured by Mitsubishi Chemical Corporation, bisphenol AF-type epoxy resin), "YL-7800" (manufactured by Mitsubishi Chemical Corporation, fluorene-type epoxy resin), "jER1010" (manufactured by Mitsubishi Chemical Corporation, solid bisphenol A-type epoxy resin), and "jER1031S" (manufactured by Mitsubishi Chemical Corporation, tetraphenylethane-type epoxy resin). These may be used individually or in combination of two or more types.

[0085] [Active Ester Compounds] Active ester compounds are compounds that contain at least one ester bond in their structure, and on both sides of the ester bond, aliphatic chains, aliphatic rings, or aromatic rings are bonded. Examples of active ester compounds include compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. They are obtained by a condensation reaction between at least one compound of a carboxylic acid compound, an acid chloride, or a thiocarboxylic acid compound and at least one compound of a hydroxy compound or a thiol compound. In particular, from the viewpoint of improving heat resistance, it is preferable that they be obtained from a carboxylic acid compound or an acid chloride and a hydroxy compound, and phenol compounds or naphthol compounds are preferred as the hydroxy compound. Active ester compounds may be used alone or in combination of two or more.

[0086] Examples of the carboxylic acid compounds mentioned above include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

[0087] Examples of the above-mentioned acid chlorides include acetyl chloride, acrylate chloride, methacrylate chloride, malonyl chloride, succinate dichloride, diglycolyl chloride, glutarate dichloride, suberate dichloride, sebacate dichloride, adipic acid dichloride, dodecanediol dichloride, azera oil chloride, 2,5-franzicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, and 4,4'-azodibenzoyl dichloride.

[0088] Examples of the above-mentioned phenol compounds and naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, phenol novolac, and phenol resins described later. Here, "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by the condensation of two molecules of phenol with one molecule of dicyclopentadiene.

[0089] Preferred examples of active ester compounds include active ester compounds containing a dicyclopentadiene-type diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated phenol novolac, active ester compounds containing a benzoylated phenol novolac, the compound described in Example 2 of International Publication No. 2020 / 095829, and the compounds disclosed in International Publication No. 2020 / 059625. Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene-type diphenol structure are more preferred. The dicyclopentadiene-type diphenol structure represents a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

[0090] 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 naphthalene structure, and "EXB9416-70BK" (manufactured by DIC Corporation), and phenol novolat Examples of active ester compounds containing acetylated compounds include "DC808" (manufactured by Mitsubishi Chemical Corporation), examples of active ester compounds containing benzoylated compounds of phenol novolac include "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation), examples of active ester curing agents that are acetylated compounds of phenol novolac include "DC808" (manufactured by Mitsubishi Chemical Corporation), and examples of phosphorus atom-containing active ester curing agents include "EXB-9050L-62M" manufactured by DIC Corporation.

[0091] Regarding the blending ratio of the active ester compound and epoxy resin, the ratio of the active ester equivalent (α) to the epoxy equivalent (β) (α / β) is preferably 0.5 to 1.5, more preferably 0.8 to 1.2, and even more preferably 0.90 to 1.10. If it falls outside the above range, there is a risk that excess epoxy groups or active ester groups will remain in the system, which may lead to deterioration of properties in high-temperature storage tests (e.g., 150°C, 1000 hours) or long-term reliability tests under high-temperature and high-humidity conditions (e.g., temperature: 85°C, humidity: 85%).

[0092] [Phenol Resins] Phenolic resins are compounds having two or more phenolic hydroxyl groups in their molecules. Examples of phenol resins other than phenol resin (B) include, but are not limited to, reaction products of phenols and aldehydes, reaction products of phenols and diene compounds, reaction products of phenols and ketones, reaction products of phenols and substituted biphenyls, reaction products of phenols and substituted phenyls, reaction products of bisphenols and aldehydes, etc. Furthermore, these may be used individually or in combination of multiple types. Specific examples of the above raw materials are given below, but are not limited to these. <Phenols> Phenol, alkyl-substituted phenol, aromatic-substituted phenol, hydroquinone, resorcinol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc. <Aldehydes> Formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural, etc. <Diene Compounds> Dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc. <Ketones> Acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, fluorenone, etc. <Substitutive biphenyls> 4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, 4,4'-bis(hydroxymethyl)-1,1'-biphenyl, etc. <Substitutive phenyls> 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene, etc.

[0093] [Polyphenylene ether compounds] From the viewpoint of heat resistance and electrical properties, polyphenylene ether compounds are preferably polyphenylene ether compounds having ethylenically unsaturated bonds, and more preferably polyphenylene ether compounds having acrylic groups, methacrylic groups, or styrene structures. Commercially available products include SA-9000-111 (manufactured by SABIC, a polyphenylene ether compound having methacrylic groups), OPE-2St 1200 (manufactured by Mitsubishi Gas Chemical Co., Ltd., a polyphenylene ether compound having a styrene structure), and OPE-2St 2200 (manufactured by Mitsubishi Gas Chemical Co., Ltd., a polyphenylene ether compound having a styrene structure). The number average molecular weight (Mn) of the polyphenylene ether compound is preferably 500 to 5000, more preferably 2000 to 5000, and even more preferably 2000 to 4000. If the molecular weight is less than 500, the heat resistance of the cured product tends not to be sufficient. Furthermore, if the molecular weight is greater than 5000, the melt viscosity increases, and sufficient fluidity cannot be obtained, which tends to lead to molding defects. In addition, reactivity decreases, requiring a long time for the curing reaction, and the amount of unreacted material that is not incorporated into the curing system increases, lowering the glass transition temperature of the cured product and tending to reduce the heat resistance of the cured product. If the number average molecular weight of the polyphenylene ether compound is between 500 and 5000, it is possible to exhibit excellent heat resistance and moldability while maintaining excellent low dielectric properties. The number average molecular weight here can be specifically measured using gel permeation chromatography or the like.

[0094] Polyphenylene ether compounds may be obtained by polymerization reactions, or by redistributing high molecular weight polyphenylene ether compounds with a number average molecular weight of about 10,000 to 30,000. Alternatively, these may be used as raw materials and reacted with compounds having ethylenically unsaturated bonds, such as methacrylic chloride, acrylic chloride, and chloromethylstyrene, to impart radical polymerizability. Polyphenylene ether compounds obtained by redistribution reactions can 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 induce a redistribution reaction. Polyphenylene ether compounds obtained by such redistribution reactions are preferable because they have hydroxyl groups derived from phenolic compounds that contribute to curing at both ends of the molecular chain, thus maintaining even higher heat resistance, and because functional groups can be introduced to both ends of the molecular chain even after modification with a compound having ethylenically unsaturated bonds. Furthermore, polyphenylene ether compounds obtained by polymerization reactions are preferable because they exhibit excellent fluidity.

[0095] The molecular weight of polyphenylene ether compounds can be adjusted by adjusting polymerization conditions, etc., in the case of polyphenylene ether compounds obtained by polymerization reactions. In the case of polyphenylene ether compounds obtained by redistribution reactions, the molecular weight of the resulting polyphenylene ether compound can be adjusted by adjusting the conditions of the redistribution reaction, etc. More specifically, this can be done by adjusting the amount of phenolic compound used in the redistribution reaction. That is, the higher the amount of phenolic compound used, the lower the molecular weight of the resulting polyphenylene ether compound. In this case, poly(2,6-dimethyl-1,4-phenylene ether) can be used as the high molecular weight polyphenylene ether compound that undergoes the redistribution reaction. Furthermore, the phenolic compound used in the above redistribution reaction is not particularly limited, but polyfunctional phenolic compounds having two or more phenolic hydroxyl groups in the molecule, such as bisphenol A, phenol novolac, and cresol novolac, are preferably used. These may be used individually or in combination of two or more.

[0096] The content of the polyphenylene ether compound is not particularly limited, but is preferably 5 to 1000 parts by mass, and more preferably 10 to 750 parts by mass, when the total amount of epoxy resin (A) and phenolic resin (B) is 100 parts by mass. When the content of the polyphenylene ether compound is within the above range, it is preferable not only because it is excellent in heat resistance and other properties, but also because it is possible to obtain a cured product that fully exhibits the excellent dielectric properties of the polyphenylene ether compound.

[0097] [Compounds containing ethylenically unsaturated bonds] Compounds containing ethylenically unsaturated bonds are compounds that have one or more ethylenically unsaturated bonds in their molecule that can be polymerized by heat or light, regardless of whether a polymerization initiator is used or not. Examples of compounds containing ethylenically unsaturated bonds include, but are not limited to, reaction products of the above-mentioned phenolic resin with halogenated compounds containing ethylenically unsaturated bonds (chloromethylstyrene, allyl chloride, methallyl chloride, acrylate chloride, methacrylate chloride, etc.), reaction products of ethylenically unsaturated phenols (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) with halogenated compounds (1,4-bis(chloromethyl)benzene, 4,4'-bis(chloromethyl)biphenyl, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuryl chloride, etc.), reaction products of epoxy resins or alcohols with (meth)acrylic acids (acrylic acid, methacrylic acid, etc.), and acid-modified products thereof. Furthermore, these may be used individually or in combination of multiple types.

[0098] [Maleimide Compounds] The curable resin composition of this embodiment may contain maleimide compounds. Maleimide compounds are compounds having one or more maleimide groups in their molecule. Examples of maleimide compounds include 4,4'-diphenylmethanebismaleimide, polyphenylmethanemaleimide, m-phenylenebismaleimide, 2,2'-bis[4-(4-maleimoidphenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, 4,4'-diphenyletherbismaleimide, 4,4'-diphenylsulfonebismaleimide, 1,3-bis(3-maleimoidphenoxy)benzene, 1,3-bis(4-maleimoidphenoxy) Phenoxybenzene, Zyloc-type maleimide compounds (anilix maleimide, manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenylaralkyl-type maleimide compounds (solidified by solvent distillation under reduced pressure of a resin solution containing the maleimide compound (M2) described in Example 4 of Japanese Patent Publication No. 2009-001783), bisaminocumylbenzene-type maleimide (maleimide compound described in International Publication No. 2020 / 054601), maleimide compounds having an indan structure described in Japanese Patent No. 6629692 or International Publication No. 2020 / 217679, MATERIAL STAGE Vol. 18, No. 12 2019 "Continued Epoxy Resin CAS Number Story - Curing Agent CAS Number Memo No. 31 Bismaleimide (1)" and MATERIAL STAGE Vol. 19, No. 2. Maleimide compounds, etc., as described in "Continued Story of Epoxy Resin CAS Numbers - Memorandum on CAS Numbers for Hardeners, Part 32: Bismaleimide (2)" (2019), are examples, but are not limited to these. Furthermore, these may be used individually or in combination of multiple types.

[0099] [Cyanate Ester Resins] Cyanate ester resins are cyanate ester compounds obtained by reacting phenol resins with cyanide halides. Specific examples include, but are not limited to, dicyanate benzene, tricyanate benzene, dicyanate naphthalene, dicyanate biphenyl, 2,2'-bis(4-cyanatephenyl)propane, bis(4-cyanatephenyl)methane, bis(3,5-dimethyl-4-cyanatephenyl)methane, 2,2'-bis(3,5-dimethyl-4-cyanatephenyl)propane, 2,2'-bis(4-cyanatephenyl)ethane, 2,2'-bis(4-cyanatephenyl)hexafluoropropane, bis(4-cyanatephenyl)sulfone, bis(4-cyanatephenyl)thioether, phenol novolac cyanate, and phenol-dicyclopentadiene cocondensates in which the hydroxyl groups have been converted to cyanate groups. Furthermore, these may be used individually or in combination of multiple types. In addition, the cyanate ester compound whose synthesis method is described in Japanese Patent Application Publication No. 2005-264154 is particularly preferred as a cyanate ester compound because it has excellent low hygroscopicity, flame retardancy, and dielectric properties. The cyanate ester resin may also contain catalysts such as zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octoate, tin octoate, lead acetylacetonate, or dibutyltin maleate in order to trimerize the cyanate group and form a sym-triazine ring as needed.

[0100] The catalyst is preferably used in an amount of 0.0001 to 0.10 parts by mass, more preferably 0.00015 to 0.0015 parts by mass, per 100 parts by mass of the curable resin composition.

[0101] [Isocyanate resin] An isocyanate resin is a compound that has two or more isocyanate groups in its molecule. Examples of isocyanate resins include, but are not limited to, aromatic diisocyanates such as p-phenylenediisocyanate, m-phenylenediisocyanate, p-xylenediisocyanate, m-xylenediisocyanate, 2,4-tollylenediisocyanate, 2,6-tollylenediisocyanate, 4,4'-diphenylmethanediisocyanate, and naphthalenediisocyanate; aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylenediisocyanate, 4,4'-dicyclohexylmethanediisocyanate, hydrogenated xylenediisocyanate, norbornene diisocyanate, and lysine diisocyanate; polyisocyanates such as one or more isocyanate monomers or isocyanate compounds obtained by trimerizing the above diisocyanate compounds; and polyisocyanates obtained by urethane reaction between the above isocyanate compounds and polyol compounds. Furthermore, these can be used individually or in combination.

[0102] [Polyamide Resins] Examples of polyamide resins include reaction products of one or more of diamines, diisocyanates, or oxazolines with dicarboxylic acids, reaction products of diamines and acid chlorides, and ring-opening polymers of lactam compounds. These may be used individually or in combination of multiple types. Specific examples of the above raw materials are given below, but the material is not limited to these.<Diamines> Ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-diaminopentane, 2-methyl 1,8-diaminooctane, dimer amine, cyclohexanediamine, bis-(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, xylylenediamine, norbornanediamine, isophoronediamine, bisaminomethyltricyclodecane, phenylenediamine, diethyltoluenediamine, naphthalenediamine, diaminodiphenylmethane, bis(4-amino-3,5-dimethylphenyl)methane, bis(4-amino-3,5-diethylphenyl)methane 4,4'-methylenebis-o-toluidine, 4,4'-methylenebis-o-ethylaniline, 4,4'-methylenebis-2-ethyl-6-methylaniline, 4,4'-methylenebis-2,6-diisopropylaniline, 4,4-ethylenedianiline, diaminodiphenylsulfone, diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-amino [phenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, 9,9-bis(4-aminophenyl)fluorene, 2,7-diaminofluorene, aminobenzylamine, diaminobenzophenone, etc.<Diisocyanates> Benzene diisocyanate, toluene diisocyanate, 1,3-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)cyclohexane, bis(4-isocyanatophenyl)methane, isophorone diisocyanate, 1,3-bis(2-isocyanato-2-propyl)benzene, 2,2-bis(4-isocyanatophenyl)hexafluoropropane, dicyclohexylmethane-4,4'-diisocyanate, etc. <Dicarboxylic acids> Oxalic acid, malonic acid, succicic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanediic acid, dodecanediic acid, terephthalic acid, isophthalic acid, 5-hydroxyisophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, cyclohexanedicarboxylic acid, biphenyldicarboxylic acid, naphthalenedicarboxylic acid, benzophenonedicarboxylic acid, francicarboxylic acid, 4,4'-dicarboxydiphenyl ether, 4,4'-dicarboxydiphenyl sulfide, etc. <Acid Chlorides> Acetyl chloride, acrylate chloride, methacrylate chloride, malonyl chloride, succinate dichloride, diglycolyl chloride, glutarate dichloride, suberate dichloride, sebacate dichloride, adipic acid dichloride, dodecane dioyl chloride, azera oil chloride, 2,5-franzicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesinate chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyl dicarbonyl chloride, 4,4'-azodibenzoyl dichloride, etc. <Lactams> ε-caprolactam, ω-undecane lactam, ω-laurolactam, etc.

[0103] [Polyimide Resin] Examples of polyimide resins include, but are not limited to, the reaction products of the above-mentioned diamine and the tetracarboxylic dianhydrides exemplified below. Furthermore, these may be used individually or in combination of multiple types. <Tetracarboxylic Dianhydrides> 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2-dicarboxylic anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4 '-diphenylsulfontetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, methylene-4,4'-diphthalic acid dianhydride, 1,1-ethylidene-4,4'-diphthalic acid dianhydride, 2,2'-propyridene-4,4'-diphthalic acid dianhydride, 1,2-ethylene-4,4'-diphthalic acid dianhydride, 1,3-trimethylene-4,4'-diphthalic acid dianhydride, 1,4-tetramethylene-4,4'-diphthalic acid dianhydride, 1,5-pentamethylene-4,4'- Diphthalic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride, thio-4,4'-diphthalic acid dianhydride, sulfonyl-4,4'-diphthalic acid dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4- [Dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-Dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 2,3,6,7-anthracenetetracarboxylic acid dianhydride, 1,2,7,8-phenanthrenetetracarboxylic acid dianhydride, ethylenetetracarboxylic acid dianhydride, 1,2,3,4-butanetetracarboxylic acid dianhydride, 1, 2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride (Bonic acid) dianhydride, 1,1-ethylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 2,2-propyridene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2,2,2]octo-7-ene-2,3,5,6-tetracarboxylic acid dianhydride Water compounds, rel-[1S,5R,6R]-3-oxabicyclo[3,2,1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, ethylene glycol-bis-(3,4-dicarboxylic acid anhydride phenyl) ether, 4,4'-biphenylbis(trimellitic acid monoester anhydride), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, etc.

[0104] [Polybutadiene and its modified products] Polybutadiene and its modified products are compounds that have polybutadiene or a structure derived from polybutadiene within their molecule. The structure derived from polybutadiene may have some or all of its unsaturated bonds converted to single bonds by hydrogenation. Examples of polybutadiene and its modified products include, but are not limited to, polybutadiene, hydroxyl-terminated polybutadiene, terminally (meth)acrylated polybutadiene, carboxylic acid-terminated polybutadiene, amine-terminated polybutadiene, and styrene-butadiene rubber. Furthermore, these may be used individually 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, RICON-184 (all manufactured by Clay Valley Corporation), and 1,2-SBS (manufactured by Nippon Soda Co., Ltd.). Examples of polybutadiene include B-1000, B-2000, and B-3000 (all manufactured by Nippon Soda Co., Ltd.). The weight-average molecular weight of polybutadiene and styrene-butadiene rubber is preferably 500 to 10000, more preferably 750 to 7500, and even more preferably 1000 to 5000. Below the lower limit of the above range, the volatility is high, making it difficult to adjust the solid content during prepreg preparation, and above the upper limit of the above range, the compatibility with other curable resins deteriorates. In general, in the case of compounds containing heteroatoms such as oxygen and nitrogen, such as bismaleimide and polymaleimide, it is difficult to ensure compatibility with low-polarity compounds such as compounds mainly composed of hydrocarbons or compounds consisting only of hydrocarbons, due to their polarity.

[0105] [Polystyrene and its modified products] Polystyrene and its modified products are polystyrene or compounds that have a structure derived from polystyrene within their molecules. Examples of polystyrene and its modified products include polystyrene, styrene-2-isopropenyl-2-oxazoline copolymer (Epocross RPS-1005, RP-61, both manufactured by Nippon Shokubai Co., Ltd.), SEP (styrene-ethylene-propylene copolymer: Septon 1020, manufactured by Kuraray Co., Ltd.), SEPS (styrene-ethylene-propylene-styrene copolymer: Septon 2002, Septon 2004F, Septon 2005, Septon 2006, Septon 2063, Septon 2104, all manufactured by Kuraray Co., Ltd.), 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 (compound having hydroxyl groups at the ends of styrene-ethylene / ethylene-propylene-styrene block copolymer: 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 7125F, Hybrar 7311F Examples include, but are not limited to, polystyrene-isobutylene-styrene block copolymers (SIBS: SIBSTAR073T, SIBSTAR102T, SIBSTAR103T (all manufactured by Kaneka Corporation), Septon V9827 (manufactured by Kuraray Co., Ltd.)), etc. Furthermore, these may be used individually or in combination. Polystyrene and its modified products are preferable to have those without unsaturated bonds because they have higher heat resistance and are less susceptible to oxidative degradation.Furthermore, while there are no particular restrictions on the weight-average molecular weight of polystyrene and its modified products as long as it is 10,000 or more, if it is too high, the compatibility with polyphenylene ether compounds, as well as low molecular weight components with a weight-average molecular weight of about 50 to 1,000 and oligomer components with a weight-average molecular weight of about 1,000 to 5,000 deteriorates, making it difficult to ensure mixing and solvent stability. Therefore, it is preferable that the weight-average molecular weight be around 10,000 to 300,000.

[0106] [Polyethylene and Modified Products thereof] Polyethylene and modified products thereof refer to polyethylene or compounds having a structure derived from polyethylene within their molecules. Examples of polyethylene and modified products thereof include, but are not limited to, ethylene-propylene copolymers, ethylene-styrene copolymers, ethylene-propylene-ethylidene norbornene copolymers (Mitsui Chemicals, Ltd. EBT: K-8370EM, K-9330M, etc.), ethylene-propylene-vinyl norbornene copolymers (Mitsui Chemicals, Ltd. VNB-EPT: PX-006M, PX-008M, PX-009M, etc.), 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 and ethylene-propylene-vinyl norbornene copolymers that contain a crosslinkable structure. Furthermore, these may be used individually or in combination of multiple types. While there are no particular restrictions on the weight-average molecular weight of polyethylene and its modified products as long as it is 10,000 or more, if it is too high, the compatibility with polyphenylene ether compounds, as well as low molecular weight components with a weight-average molecular weight of about 50 to 1,000 and oligomer components with a weight-average molecular weight of about 1,000 to 5,000 deteriorates, making it difficult to ensure mixing and solvent stability. Therefore, it is preferable that the molecular weight be around 10,000 to 300,000.

[0107] [Benzoxazine Compounds] As benzoxazine compounds, any compound having two or more dihydrobenzoxazine rings in one molecule can be used, as long as it is generally known. Examples include bisphenol A type benzoxazine BA-BXZ (manufactured by Konishi Chemical Co., Ltd.), bisphenol F type benzoxazine BF-BXZ (manufactured by Konishi Chemical Co., Ltd.), bisphenol S type benzoxazine BS-BXZ (manufactured by Konishi Chemical Co., Ltd.), phenolphthalein type benzoxazine, etc., but are not particularly limited. These benzoxazine compounds can be used individually or in appropriate mixtures of two or more.

[0108] The curable resin composition of this embodiment is obtained by preparing the above components in predetermined proportions, pre-curing at 130 to 180°C for 30 to 500 seconds, and then post-curing at 150 to 200°C for 2 to 15 hours to allow the curing reaction to proceed sufficiently and obtain the cured product of this embodiment. Alternatively, the components of the curable resin composition can be uniformly dispersed or dissolved in a solvent, and then cured after removing the solvent.

[0109] The method for preparing the curable resin composition of this embodiment is not particularly limited, but the components may be uniformly mixed or prepolymerized. Mixing or prepolymerizing the components can be done using, for example, an extruder, kneader, or roll in the absence of a solvent, or a reaction vessel with a stirring device in the presence of a solvent.

[0110] A method for uniform mixing involves kneading the mixture using equipment such as a kneader, roll, or planetary mixer at a temperature in the range of 50 to 100°C to obtain a uniform curable resin composition. The obtained curable resin composition can be pulverized and then molded into cylindrical tablets using a molding machine such as a tablet machine, or into granular powder or powdery molded bodies. Alternatively, these compositions can be melted on a surface support and molded into sheets with a thickness of 0.05 mm to 10 mm to obtain molded bodies of curable resin compositions. The obtained molded bodies are non-sticky at 0 to 20°C and maintain almost no decrease in fluidity or curability even when stored at -25 to 0°C for more than a week. The obtained molded bodies can be molded into cured products using a transfer molding machine or a compression molding machine.

[0111] The curable resin composition of this embodiment can also be made into a varnish-like composition (hereinafter simply referred to as varnish) by adding an organic solvent. The curable resin composition of this embodiment can be dissolved in a solvent such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, or N-methylpyrrolidone as needed to make a varnish, which can then be impregnated into a substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, or paper, and the resulting prepreg can be obtained by heat-drying and then hot-press-molding to obtain a cured product of the curable resin composition of this embodiment. In this case, the solvent used is in an amount that accounts for 10 to 70 parts by mass, preferably 15 to 70 parts by mass, in the mixture of the curable resin composition of this embodiment and the solvent. Alternatively, if it is a liquid composition, a curable resin composition containing carbon fibers can be obtained directly, for example, by the RTM method.

[0112] Furthermore, the curable resin composition of this embodiment can also be used as a modifier for film-type compositions. Specifically, it can be used to improve flexibility and other properties in the B-stage. Such a film-type resin composition can be obtained as a sheet-like adhesive by applying the curable resin composition of this embodiment as a curable resin composition varnish onto a release film, removing the solvent under heating, and then performing B-stage formation. This sheet-like adhesive can be used as an interlayer insulating layer in multilayer substrates and the like.

[0113] The curable resin composition of this embodiment can also be heated and melted to reduce viscosity and impregnate reinforcing fibers such as glass fibers, carbon fibers, polyester fibers, polyamide fibers, and alumina fibers to obtain a prepreg. Specific examples include, but are not limited to, glass fibers such as E glass cloth, D glass cloth, S glass cloth, Q glass cloth, spherical glass cloth, NE glass cloth, and T glass cloth, as well as inorganic fibers other than glass, and organic fibers such as poly(p-phenylene terephthalamide) (Kevlar®, manufactured by DuPont), fully aromatic polyamide, polyester, poly(p-phenylene benzoxazole), polyimide, and carbon fibers. The shape of the substrate is not particularly limited, but examples include woven fabrics, nonwoven fabrics, rovings, and chopped strand mats. As for the weaving method of the woven fabric, plain weave, twill weave, etc., are known, and these can be appropriately selected and used depending on the intended application and performance. Furthermore, glass woven fabrics that have been opened or surface-treated with silane coupling agents are preferably used. The thickness of the base material is not particularly limited, but is preferably about 0.01 to 0.4 mm. Alternatively, a prepreg can be obtained by impregnating reinforcing fibers with the above varnish and then heating and drying them.

[0114] Furthermore, laminates can also be manufactured using the above-mentioned prepregs. The laminate is not particularly limited as long as it comprises one or more prepregs, and may have any other layers. The method for manufacturing the laminate is not particularly limited and can be any generally known method as appropriate. For example, when forming a metal foil laminate, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, an autoclave molding machine, etc., can be used, and a laminate can be obtained by laminating the above-mentioned prepregs together and then heating and pressing them. At this time, the heating temperature is not particularly limited, but 65 to 300°C is preferred, and 120 to 270°C is more preferred. The pressurizing pressure is not particularly limited, but if the pressurizing pressure is too high it is difficult to adjust the solid content of the resin in the laminate and the quality is not stable, and if the pressurizing pressure is too low it becomes difficult to form air bubbles and the adhesion between layers is poor, so 2.0 to 5.0 MPa is preferred, and 2.5 to 4.0 MPa is more preferred. The laminate of this embodiment can be suitably used as a metal foil laminate described later by comprising a layer made of metal foil. By cutting the above prepreg into the desired shape, laminating it with copper foil or other materials as needed, and then applying pressure to the laminate using methods such as press molding, autoclave molding, or sheet winding molding while heating and curing a curable resin composition, electrical and electronic laminates (printed wiring boards) and carbon fiber reinforced materials can be obtained.

[0115] The curable resin composition of this embodiment can also be made into a resin sheet. One method for obtaining a resin sheet from the curable resin composition of this embodiment is to apply the curable resin composition onto a support film (support), and then dry it to form a resin composition layer on the support film. When using the curable resin composition of this embodiment to make a resin sheet, it is important that the film softens at the lamination temperature conditions (70°C to 140°C) in the vacuum lamination method and exhibits fluidity (resin flow) that allows for simultaneous lamination of the circuit board and resin filling of via holes or through holes present in the circuit board. It is preferable to blend the above components in such a way as to exhibit such characteristics. Furthermore, in order to ensure that the resulting resin sheet and circuit board (copper-clad laminate, etc.) exhibit consistent performance in any desired area, and to prevent phenomena such as locally different characteristic values ​​caused by phase separation, uniformity of appearance is required.

[0116] Here, the diameter of the through-holes in the circuit board is 0.1 to 0.5 mm, and the depth is 0.1 to 1.2 mm, and it is preferable to be able to fill them with resin within this range. When laminating both sides of the circuit board, it is desirable that the through-holes be filled to about half their extent.

[0117] A specific method for manufacturing the above-mentioned resin sheet is to prepare a varnished resin composition by incorporating an organic solvent, apply the varnished resin composition to the surface of a support film (Y), and then dry the organic solvent by heating or blowing hot air to form a resin composition layer (X).

[0118] The organic solvents used here preferably include ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. It is also preferable to use them in a proportion that results in a non-volatile content of 30 to 60% by mass.

[0119] Furthermore, the thickness of the formed resin composition layer (X) must be greater than or equal to the thickness of the conductor layer. Since the thickness of the conductor layer of the circuit board is in the range of 5 to 70 μm, it is preferable that the thickness of the resin composition layer (X) be 10 to 100 μm. In addition, the resin composition layer (X) in the present invention may be protected by a protective film, which will be described later. By protecting it with a protective film, it is possible to prevent dirt and other debris from adhering to the surface of the resin composition layer and to prevent scratches.

[0120] The above-mentioned support film and protective film can be made of polyolefins such as polyethylene, polypropylene, and polyvinyl chloride, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polycarbonate, polyimide, and also release paper, copper foil, aluminum foil, and other metal foils. The support film and protective film may be treated with a mat treatment, corona treatment, or release treatment. The thickness of the support film is not particularly limited, but is 10 to 150 μm, preferably in the range of 25 to 50 μm. The thickness of the protective film is preferably 1 to 40 μm.

[0121] The support film (Y) described above is peeled off after lamination to the circuit board or after an insulating layer has been formed by heat curing. If the support film (Y) is peeled off after the resin composition layer constituting the resin sheet has been heat cured, it is possible to prevent the adhesion of dust and other debris during the curing process. When peeling off after curing, the support film is treated with a release agent beforehand.

[0122] Furthermore, a multilayer printed circuit board can be manufactured from the resin sheet obtained as described above. For example, if the resin composition layer (X) is protected by a protective film, these are removed, and then the resin composition layer (X) is laminated to one or both sides of the circuit board so that it is in direct contact with the circuit board, for example, by a vacuum lamination method. The lamination method may be batch or continuous on a roll. If necessary, the resin sheet and circuit board may be heated (preheated) before lamination. The lamination conditions are preferably a pressure temperature (lamination temperature) of 70 to 140°C and a pressure of 1 to 11 kgf / cm². ２ (9.8 x 10 ４ ~107.9 x 10 ４ N / m ２ It is preferable to use this method, and it is preferable to laminate under reduced pressure of 20 mmHg (26.7 hPa) or less.

[0123] Furthermore, semiconductor devices can be manufactured using the curable resin composition of this embodiment. Examples of semiconductor devices include DIP (Dual In-Line Package), QFP (Quad Flat Package), BGA (Ball Grid Array), CSP (Chip Size Package), SOP (Small Outline Package), TSOP (Thin Small Outline Package), and TQFP (Thin Quad Flat Package).

[0124] The curable resin composition and its cured product according to this embodiment can be used in a wide range of fields. Specifically, it can be used in various applications such as molding materials, adhesives, composite materials, and paints. Because the cured product of the curable resin composition described in the present invention exhibits excellent low coefficient of thermal expansion and low dielectric properties, it is suitably used in electrical and electronic components such as encapsulants for semiconductor devices, encapsulants for liquid crystal display devices, encapsulants for organic EL devices, laminates (printed wiring boards, BGA substrates, build-up substrates, etc.), composite materials for lightweight, high-strength structural materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, and 3D printing.

[0125] In order to satisfy the heat resistance requirements of the curable resin composition of this embodiment, it is preferable that the glass transition temperature measured by the method shown in the examples described later is 200°C or higher, and more preferably 220°C or higher. Furthermore, in order to satisfy the requirements of easy decomposition at high temperatures, it is preferable that the weight loss rate measured by the method shown in the examples described later is 80% or higher, and more preferably 85% or higher.

[0126] The present invention will be specifically described below with reference to examples and comparative examples. In this text, "parts" and "%" refer to "parts by mass" and "mass%", respectively. The softening point and melt viscosity were measured by the following methods: • Softening point: Measured according to the method in accordance with JIS K-7234. • Melt viscosity: Measured using the ICI melt viscosity (150°C) cone plate method, in units of Pa·s.

[0127] GPC (Gel Permeation Chromatography) Analysis Manufacturer: Waters Columns: SHODEX GPC KF-601 (2), KF-602, KF-602.5, KF-603 Flow Rate: 0.5 ml / min. Column Temperature: 40°C Solvent Used: THF (Tetrahydrofuran) Detector: RI (Differential Refraction Detector)

[0128] ・ １３ C-NMR (Nuclear Magnetic Resonance) Analysis Manufacturer: NEC Corporation Equipment: JNM-ECS400 Number of Total Cycles: 16384 Relaxation Time: 2 seconds Solvent Used: Acetone-d6 Measurement Temperature: Room Temperature

[0129] • High-performance liquid chromatography (HPLC) analysis Shimadzu Corporation liquid delivery unit LC-20AD Shimadzu Corporation photodiode array detector SPD-M20A Shimadzu Corporation column oven CTO-20A Column: Intersil ODS-2, 5 μm, 4.6 × 250 mm 40℃ Mobile Phase A: Acetonitrile (AN) Mobile Phase B: Water (W) Time Program: 0-28 min. AN / W = 30% / 70% → 100% / 0% 28-40 min. AN / W = 100% / 0% Flow Rate: 1.0 mL / min. Detection: UV274m, PDA

[0130] [Synthesis Example 1] 132 parts phenol, 26 parts resorcinol, and 5 parts p-toluenesulfonic acid were charged into a four-necked flask equipped with a stirrer, thermometer, and condenser, and the mixture was stirred and heated to 80°C. A solution of 29 parts dicyclopentadiene dissolved in 6 parts toluene was added dropwise to this reaction mixture, and the mixture was reacted at 80°C for 6 hours, followed by 135°C for 7 hours. After the reaction was complete, excess sodium tripolyphosphate, 40 parts water, and 150 parts toluene were added to neutralize and wash the mixture. Then, unreacted phenol and resorcinol were removed from the oil layer by steam distillation under reduced pressure to obtain 75 parts of the phenol resin (P-1) represented by formula (5) above. In formula (5) above, the obtained phenol resin (P-1) had l2=0, n2=2.3, p2=0, and r2=1 or 2. The softening point of the obtained phenol resin was 109°C, and the hydroxyl group equivalent was 152 g / eq. The GPC results are shown in Figure 1. The GPC chart of the obtained phenolic resin is shown in Figure 1, and the HPLC chart is shown in Figure 2. In the above formula (5), of the total amount of phenolic resin where l2=0, n2=1, and p2=0, the proportion of the component where one of r2 is 1 and the other is 2 was 29.7 area % in HPLC area percentage.

[0131] [Synthesis Example 2] 120 parts of phenol and 8 parts of p-toluenesulfonic acid were charged into a four-necked flask equipped with a stirrer, thermometer, and condenser, and the mixture was stirred and heated to 80°C. 15 parts of 4-hydroxybenzaldehyde were added dropwise to this reaction mixture, and the mixture was reacted at 80°C for 6 hours, followed by 135°C for 7 hours. After the reaction was complete, excess sodium tripolyphosphate, 40 parts of water, and 150 parts of toluene were added to neutralize and wash the mixture. Then, the unreacted phenol was removed from the oil layer under reduced pressure, yielding 68 parts of the phenol resin (P-2) represented by formula (6) above. In formula (6) above, the obtained phenol resin (P-2) is R ４２ The atoms were hydrogen atoms, with p2=0, p32=0, r2=1, r52=1, and n2=1.1. The softening point of the obtained phenolic resin was 120°C, and the hydroxyl equivalent was 98 g / eq. The GPC chart of the obtained phenolic resin is shown in Figure 3.

[0132] [Synthesis Example 3] A flask equipped with a thermometer, dropping funnel, condenser, and stirrer was purged with nitrogen gas and charged with 147 parts by mass of phenol resin obtained in Synthesis Example 1, 506 parts by mass of epichlorohydrin, 97 parts by mass of dimethyl sulfoxide, and 12 parts by mass of water. The mixture was heated to 55°C under stirring and dissolved. Next, 45 parts by mass of flake sodium hydroxide were added in installments over 100 minutes, and the mixture was reacted further at 55°C for 90 minutes and then at 70°C for 30 minutes. After the reaction was complete, the dimethyl sulfoxide and excess epichlorohydrin were removed by distillation using a rotary evaporator under reduced pressure, and 517 parts of methyl isobutyl ketone were added to the residue and dissolved. 188 parts by mass of water were added to this methyl isobutyl ketone solution, and the by-product salt and dimethyl sulfoxide were washed with water, and the aqueous layer was separated and removed. Then, 13 parts by mass of a 30% by weight aqueous sodium hydroxide solution was added and the mixture was reacted at 75°C for 1 hour. The washing solution was then rinsed repeatedly with water until it became neutral. The aqueous layer was then separated and removed, and methyl isobutyl ketone was removed by distillation using a rotary evaporator under reduced pressure, yielding 148 parts by mass of epoxy resin (EP-1) represented by formula (3). In formula (3), the obtained epoxy resin (EP-1) had l1=0, n1=2.5, p1=0, and r1=1 or 2. The obtained epoxy resin had a softening point of 76°C (ASTM), a melt viscosity at 150°C of 0.14 Pa·s, and an epoxy equivalent of 215 g / eq. The GPC results are shown in Figure 4. The HPLC chart of the obtained epoxy resin is shown in Figure 5. In formula (3), of the total amount of epoxy resin where l1=0, n1=1, and p1=0, the proportion of the component where one r1 was 1 and the other was 2 was 24.8 area % in HPLC area percentage.

[0133] Other phenolic and epoxy resins used are listed below: • EP-2: EPPN-503 (manufactured by Nippon Kayaku Co., Ltd., softening point 88°C (ASTM), melt viscosity 1.96 Pa·s, epoxy equivalent 183 g / eq.) • EP-3: EOCN-102S (manufactured by Nippon Kayaku Co., Ltd., softening point 71°C (ASTM), melt viscosity 0.36 Pa·s, epoxy equivalent 213 g / eq.) • PN-3: PN (manufactured by Meiwa Kasei Co., Ltd., softening point 83.6°C, hydroxyl group equivalent 107 g / eq.)

[0134] [Examples 1-3, Comparative Examples 1-2] The obtained epoxy resin, phenolic resin, and triphenylphosphine were weighed out in the proportions (parts by mass) shown in Table 1 and uniformly mixed and kneaded using a mixing roll. １３ The 1C-NMR results are shown in Figures 6-8, and the results for Comparative Examples 1-2 are shown. １３ The results of the C-NMR are shown in Figures 9 and 10, respectively.

[0135]

[0136] [Preparation of Cured Products] The obtained epoxy resin, phenolic resin, and triphenylphosphine were weighed out in the proportions (parts by mass) shown in Table 2 and uniformly mixed and kneaded using a mixing roll. After that, the mixture was molded by transfer molding, demolded, and cured at 160°C for 2 hours and 180°C for 6 hours to obtain evaluation test pieces, after which the cured properties were measured under the following conditions.

[0137] [Heat resistance and glass transition temperature (Tg)] A sample measuring 5 mm wide x 40 mm long x 0.5 mm thick was inserted into a dynamic viscoelasticity tester (TA Instrument, DMA Q800) and heated from 30°C to 270°C at a rate of 2°C / min. The temperature at which tanδ reached its maximum value was measured and defined as Tg.

[0138] [Weight Loss Rate] The weight loss rate from the initial state was measured using a TG / DTA6200 (manufactured by Hitachi High-Tech Science Corporation) when the temperature was increased to 550°C at a rate of 10°C / min under a nitrogen atmosphere and then held at 550°C for 30 minutes.

[0139]

[0140] As shown in Table 1, in Examples 4 to 6, cured products superior in heat resistance and ease of decomposition at high temperatures (weight loss rate) were obtained compared to Comparative Examples 3 and 4.

[0141] The curable resin composition and carbon fiber reinforced composite material of the present invention are suitably used for lightweight, high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics.

Claims

1. A curable resin composition comprising an epoxy resin (A) represented by the following formula (1) and a phenolic resin (B) represented by the following formula (2), １３ A curable resin composition in which, in 1C-NMR analysis, the proportion of the integral value of aromatic carbon atoms among the integral values ​​of all carbon atoms contained in the epoxy resin (A) and the phenolic resin (B) is 30% or more and 60% or less. (In equations (1) and (2), there are multiple R １ Each of these independently represents an alkyl group having 1 to 5 carbon atoms, or an aromatic group having 1 to 20 carbon atoms, which may have substituents. There are multiple R's. ２ Each of the following independently represents an alkyl group having 1 to 5 carbon atoms, or an aromatic group having 1 to 20 carbon atoms that may have substituents. The multiple p1 values ​​are each an integer from 0 to 3. The multiple p2 values ​​are each an integer from 0 to 3. G represents a substituted or unsubstituted glycidyl group. The multiple r1 values ​​are each independently 1 or 2. The multiple r2 values ​​are each independently 1 or 2. The multiple X values ​​are each independently a hydrocarbon group having 1 to 20 carbon atoms that may have substituents. The multiple Y values ​​are each independently a hydrocarbon group having 1 to 20 carbon atoms that may have substituents. n1 and n2 are the average values ​​of the number of repetitions, where 1 < n1 < 5 and 1 < n2 < 5.

2. The curable resin composition according to claim 1, wherein the epoxy resin (A) is represented by the following formula (3) or (4). (In equations (3) to (4), there are multiple R １ Each of these independently represents an alkyl group having 1 to 5 carbon atoms, or an aromatic group having 1 to 20 carbon atoms, which may have substituents. There are multiple R's. ３ Each of these independently represents an alkyl group having 1 to 5 carbon atoms, or an aromatic group having 1 to 20 carbon atoms, which may have substituents. There are multiple R's. ４ Each of the following independently represents an alkyl group with 1 to 5 carbon atoms, or a hydrogen atom. Multiple p1 values ​​are each independently integers from 0 to 3. Multiple p3 values ​​are each independently integers from 0 to 3. G represents a substituted or unsubstituted glycidyl group. Multiple r1 values ​​are each independently 1 or 2. Multiple r5 values ​​are each independently 1 or 2. l1 is 0 or 1. n1 is the average number of repeats, where 1 < n1 < 5.

3. The curable resin composition according to claim 1, wherein the phenolic resin (B) is represented by the following formula (5) or (6). (In formulas (5) to (6), a plurality of R ２ each independently represents an alkyl group having 1 to 5 carbon atoms or an aromatic group having 1 to 20 carbon atoms which may have a substituent. A plurality of R ３２ each independently represents an alkyl group having 1 to 5 carbon atoms or an aromatic group having 1 to 20 carbon atoms which may have a substituent. A plurality of R ４２ each independently represents an alkyl group having 1 to 5 carbon atoms or a hydrogen atom. A plurality of p2s each independently represent an integer of 0 to 3. A plurality of p32s each independently represent an integer of 0 to 3. A plurality of r2s each independently represent 1 or 2. A plurality of r52s each independently represent 1 or 2. l2 is 0 or 1. n2 is an average value of the repeating number, and 1 < n2 < 5.) 4. The curable resin composition according to claim 1, further containing a curing accelerator.

5. The curable resin composition according to claim 1, further comprising one or more selected from a polymerization initiator, epoxy resin other than epoxy resin (A), active ester compound, phenol resin other than phenol resin (B), polyphenylene ether compound, compound having an ethylenically unsaturated bond, isocyanate resin, polyamide resin, maleimide compound, cyanate ester resin, polyimide resin, polybutadiene and modified thereof, polystyrene and modified thereof, polyethylene and modified thereof, and benzoxazine compound.

6. A curable resin composition according to any one of claims 1 to 5, for use with carbon fiber reinforced plastics.

7. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 5.

8. A prepreg comprising a curable resin composition according to claim 6 held on a sheet-like fibrous substrate.

9. A cured product obtained by curing the prepreg described in claim 8.

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