Curable resin composition and its cured product

Abstract

The present invention provides a curable resin composition that exhibits excellent heat resistance, low dielectric properties, and mechanical properties. [Solution] A resin composition containing an active ester resin represented by formula (1) and an epoxy resin. TIFF2026049652000016.tif17170 (In equation (1), X represents a divalent organic group represented by equation (2), Y represents a divalent organic group, and Z represents a monovalent organic group. n is the average value of the number of repetitions, and 0 <n≦20である。) TIFF2026049652000017.tif35170 (In formula (2), R independently represents a hydrocarbon group, a halogen atom, or an alkoxy group. m represents an integer from 0 to 4. * represents the bond position with the oxygen atom in formula (1).)

Description

Technical Field

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

Background Art

[0002] In recent years, due to the expansion of the fields of use of laminated boards on which electrical and electronic components are mounted, the required characteristics have become extensive and sophisticated. For example, mobile communication terminals typified by smartphones are rapidly advancing in multifunctionality, high performance, and thinning and miniaturization. In printed wiring boards used for these, high performance such as wiring miniaturization, multilayerization of wiring layers, thinning, and mechanical properties is required. In particular, with the thinning of printed wiring boards, there is a problem that warping occurs in semiconductor packages, and mounting defects are likely to occur. Especially in semiconductor packages (hereinafter referred to as PKGs) used in smartphones and the like, in order to meet the requirements of miniaturization, thinning, and high density, thinning of the PKG substrate is required. However, when the PKG substrate becomes thinner, its rigidity decreases, so problems such as large warping occur due to heating when the PKG is soldered to a mother board (PCB). These are due to the difference in the linear expansion coefficients of each member. For the PKG substrate material used for connecting a silicon chip and a mother board, in addition to the approach of material design with a small linear expansion coefficient having a high Tg above the soldering temperature, a method of reducing elasticity at high temperatures to relieve the stress generated during solder reflow (reflow furnace temperature: 260°C) may also be taken. Also, these are in the sense of imparting rigidity, and it is also important to have a high elastic modulus around room temperature (25°C).

[0003] In addition, the fifth-generation communication system "5G," whose development is currently accelerating, is expected to achieve even greater capacity and higher speed communication. 5G will utilize higher frequencies, and reducing transmission loss is crucial for realizing high-speed communication using high frequencies, thus requiring even lower dielectric properties for substrate materials. Transmission loss on printed circuit boards originates from conductor loss and dielectric loss. As described in Non-Patent Literature 1, conductor loss is proportional to the square root of the relative permittivity and the dielectric loss tangent of the dielectric material. Therefore, improving the dielectric loss tangent, which contributes more than the relative permittivity, is effective in reducing transmission loss. Examples of low-dielectric materials include thermoplastic materials such as PTFE (polytetrafluoroethylene) and LCP (liquid crystal polymer), but they have poor moldability compared to thermosetting resins. Therefore, the development of thermosetting resins with excellent low dielectric properties is desired. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] "Signal Loss Factors in High-Speed ​​Signal Transmission on Printed Circuit Boards," 29th Spring Conference of the Japan Society for Electronics Packaging, Session ID: 16P1-17, 2015. [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 04-359911 [Patent Document 2] Patent No. 7307896 [Overview of the project] [Problems that the invention aims to solve]

[0006] Against this backdrop, polymer materials with high heat resistance and excellent low dielectric properties are being investigated. For example, Patent Document 1 proposes a composition containing maleimide resin and propenyl group-containing phenol resin. However, on the other hand, because phenolic hydroxyl groups that do not participate in the reaction remain during the curing reaction, the electrical properties and low water absorption are not sufficient. Patent Document 2 investigates an epoxy resin composition using hindered phenol as a curing agent. In this composition, the Tg is deliberately lowered to around 150°C or below from the viewpoint of stress relaxation, and there is a risk that sufficient electrical properties cannot be exhibited due to the influence of hydroxyl groups generated by the curing of the epoxy resin by the phenol resin.

[0007] This invention has been made in view of the above circumstances, and aims to provide a curable resin composition and a cured product thereof that are excellent in heat resistance, low dielectric properties, and mechanical properties. [Means for solving the problem]

[0008] In other words, the present invention relates to a curable resin composition containing an activated ester resin and an epoxy resin represented by the following formula (1).

[0009] [ka]

[0010] (In equation (1), the multiple X, Y, and Z each exist independently, X represents a divalent organic group represented by equation (2) below, Y represents a divalent organic group, and Z represents a monovalent organic group. n is the average value of the number of repetitions, and 0 <n≦20である。)

[0011] [ka]

[0012] (In formula (2), the plurality of R's each independently exist and represent a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, or an alkoxy group having 1 to 10 carbon atoms. m is an integer from 0 to 4. * represents the bonding position with the oxygen atom in formula (1).)

[0013] In the present invention, "(numerical value 1) to (numerical value 2)" indicates that the upper and lower limit values are included.

Advantages of the Invention

[0014] An object of the present invention is to provide a curable resin composition and a cured product thereof that are excellent in heat resistance, low dielectric properties, and mechanical properties.

Brief Description of the Drawings

[0015] [Figure 1] Shows the GPC chart of Synthesis Example 1. [Figure 2] Shows the GPC chart of Synthesis Example 2. [Figure 3] Shows the GPC chart of Synthesis Example 3. [Figure 4] Shows the GPC chart of Synthesis Example 4. [Figure 5] Shows the GPC chart of Synthesis Example 5.

Modes for Carrying Out the Invention

[0016] Hereinafter, the embodiments according to the present invention (hereinafter, also referred to as "the present embodiment") will be described in more detail.

[0017] The curable resin composition of the present embodiment contains an active ester resin and an epoxy resin represented by the following formula (1).

[0018]

Chemical formula

[0019] In formula (1), the plurality of X, Y, and Z exist independently. X represents a divalent organic group represented by the following formula (2), Y represents a divalent organic group, and Z represents a monovalent organic group. n is the average value of the number of repetitions, where 0 < n ≤ 20, preferably 0 < n ≤ 15, more preferably 0.1 < n ≤ 10, even more preferably 0.3 ≤ n ≤ 8, even more preferably 0.5 < n ≤ 5, and particularly preferably 1 ≤ n ≤ 3. The value of n can be calculated from the value of the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) measurement. It can also be calculated from the charging ratio of the raw materials. The gel permeation chromatography (GPC) measurement in this embodiment is performed by the method described in the examples below. In the above formula (1), the content of the n = 0 form determined by differential refractive index detector detection in gel permeation chromatography (GPC) is preferably 5 area% or more and 90 area% or less, more preferably 10 area% or more and 70 area% or less, and most preferably 10 area% or more and 50 area% or less. Being within the above range provides excellent solvent solubility, compatibility, low thermal expansion, heat resistance, and dielectric properties.

[0020] Y is preferably a hydrocarbon group having 1 to 30 carbon atoms, more preferably a hydrocarbon group having 1 to 20 carbon atoms, and even more preferably a hydrocarbon group having 1 to 15 carbon atoms, from the viewpoint of dielectric properties and solubility in nonpolar solvents such as toluene. From the viewpoint of heat resistance and dielectric properties, Y is most preferably an arylene group. Any known compound can be used as the arylene group, but it is preferably one or more of phenylene, biphenylene, naphthylene, terphenylene, and anthracenylene, more preferably one or more of phenylene, biphenylene, and naphthylene, and most preferably a phenylene structure. The above arylene group may have substituents, preferably one or more selected from halogen atoms, hydrocarbon groups, and alkoxy groups, and more preferably one or more selected from hydrocarbon groups and alkoxy groups. In particular, one or more selected from hydrocarbon groups having 1 to 10 carbon atoms and alkoxy groups having 1 to 10 carbon atoms are more preferred, one or more selected from alkyl groups having 1 to 6 carbon atoms, aryl groups having 6 to 10 carbon atoms, arylalkyl groups having 7 to 10 carbon atoms (also called aralkyl groups), unsaturated aliphatic hydrocarbon groups having 2 to 6 carbon atoms and alkoxy groups having 1 to 6 carbon atoms are even more preferred, and aryl groups having 6 to 10 carbon atoms are particularly preferred.

[0021] From the viewpoint of dielectric properties and solvent solubility, Z is preferably a hydrocarbon group having 1 to 30 carbon atoms, more preferably a hydrocarbon group having 1 to 20 carbon atoms, and even more preferably a hydrocarbon group having 1 to 15 carbon atoms. From the viewpoint of heat resistance and dielectric properties, Z is most preferably an aryl group. Any known compound can be used as the aryl group, but it is preferably one or more of the phenyl group, biphenyl group, naphthyl group, terphenyl group, and anthracenyl group, and more preferably one or more of the phenyl group, biphenyl group, and naphthyl group. The above aryl group may have substituents, preferably one or more selected from halogen atoms, hydrocarbon groups, and alkoxy groups, and more preferably one or more selected from hydrocarbon groups and alkoxy groups. In particular, one or more selected from hydrocarbon groups having 1 to 10 carbon atoms and alkoxy groups having 1 to 10 carbon atoms are more preferred, one or more selected from alkyl groups having 1 to 6 carbon atoms, aryl groups having 6 to 10 carbon atoms, arylalkyl groups having 7 to 10 carbon atoms (also called aralkyl groups), unsaturated aliphatic hydrocarbon groups having 2 to 6 carbon atoms and alkoxy groups having 1 to 6 carbon atoms are even more preferred, and aryl groups having 6 to 10 carbon atoms are particularly preferred. When the above aryl group has an unsaturated aliphatic hydrocarbon group as a substituent, the unsaturated aliphatic hydrocarbon group is preferably an alkenyl group, an alkynyl group, or an allyl group, with the allyl group being more preferred. Z also has the end-sealing function necessary to achieve a specific molecular weight distribution range and viscosity optimization.

[0022] [ka]

[0023] In formula (2), each of the multiple R's exists independently and represents a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, or an alkoxy group having 1 to 10 carbon atoms. More preferably, it is an aryl group, an aralkyl group, or an alkyl group having 1 to 10 carbon atoms, even more preferably an alkyl group having 1 to 5 carbon atoms, and particularly preferably an alkyl group having 1 to 3 carbon atoms. m is an integer from 0 to 4, preferably 0 to 2, more preferably 0 to 1, and most preferably 0. * represents the bond position with the oxygen atom in formula (1).

[0024] The number-average molecular weight of the active ester resin represented by formula (1) above can be determined by differential refractometer detection in gel permeation chromatography (GPC), and is preferably 200 to 5000, more preferably 400 to 2000, and particularly preferably 600 to 1000. The weight-average molecular weight determined by differential refractometer detection in gel permeation chromatography (GPC) is preferably 500 to 8000, more preferably 600 to 4000, and particularly preferably 800 to 2000. When the number-average molecular weight and weight-average molecular weight are below the above upper limits, the solvent solubility, compatibility, fluidity, curability, low thermal expansion, and dielectric properties are excellent, and when they are above the lower limits, the heat resistance of the cured product is excellent.

[0025] The ester equivalent of the active ester resin represented by formula (1) above is preferably 150 g / eq. to 2000 g / eq., more preferably 160 g / eq. to 1000 g / eq., and particularly preferably 180 g / eq. to 500 g / eq. The ester equivalent represents the mass of the resin containing one equivalent of ester groups. If the ester equivalent is less than 150 g / eq., the heat resistance may deteriorate. If the ester equivalent exceeds 2000 g / eq., the curability may decrease. The ester equivalent can be calculated from the raw material charging ratio, or from the number-average molecular weight (Mn) value obtained by gel permeation chromatography (GPC).

[0026] The softening point of the active ester resin represented by formula (1) above is preferably 40 to 250°C, more preferably 60 to 220°C, and even more preferably 80 to 200°C. If the softening point is higher than 250°C, solvent solubility and compatibility with other resins may decrease. If the softening point is lower than 40°C, blocking may occur during storage. The softening point can be determined by the Mettler softening point method described in the examples below.

[0027] The method for producing the active ester resin represented by formula (1) above is not particularly limited, but it can be obtained by polycondensation reaction of a compound (a) having one hydroxyl group in the molecule, a compound (b) having two hydroxyl groups in the molecule, and a compound and / or an acid halide thereof having two carboxyl groups in the molecule (c). In the polycondensation reaction of components (a), (b), and (c), polycondensation reactions (esterification) proceed between component (a) and component (c), and between component (b) and component (c). In this reaction, the degree of condensation between component (b) and component (c) can be adjusted by changing conditions such as the ratio of each component, and the structure of the obtained active ester resin (for example, the number of repeats n in formula (1) above) can be adjusted. Component (b) contains bisphenols having the chemical structure represented by the following formula (3). Bisphenols having the chemical structure represented by formula (3) are preferably present in 20 to 100% by mass of component (b), and more preferably in 40 to 100% by mass. Bisphenols having the chemical structure represented by formula (3) have a cardi structure similar to bisphenol fluorene compounds, and molecular rotation is suppressed, so active ester resins using them as raw materials exhibit high heat resistance and high modulus of elasticity at room temperature. Furthermore, when the Tg exceeds a certain level, the molecular rotation of the cardi structure leads to reduced elasticity, which contributes to stress relaxation (i.e., effectively suppresses warping of the substrate).

[0028] [ka]

[0029] In equation (3) above, R and m have the same meaning as in equation (2) above.

[0030] The aforementioned component (a) has a structure derived from a monovalent phenol compound. Specifically, for example, phenol, cresol, xylenol, mesitol, orthophenylphenol, metaphenylphenol, paraphenylphenol, orthoallylphenol, metaallylphenol, paraallylphenol, 2,4-diallylphenol, 2,6-diallylphenol, 2-allyl-4-methylphenol, 2-allyl-6-methylphenol, 2-allyl-4-methoxy-6-methylphenol, 2-propargylphenol, 3-propargylphenol, Examples include 4-propargylphenol, 1-naphthol, 2-naphthol, 2-allyl-1-naphthol, 3-allyl-1-naphthol, 1-allyl-2-naphthol, 3-allyl-2-naphthol, 5-allyl-1-naphthol, 6-allyl-1-naphthol, diallylnaphthol, 2-allyl-4-methoxy-1-naphthol, 2-propargyl-1-naphthol, 3-propargyl-1-naphthol, 1-propargyl-2-naphthol, and 3-propargyl-2-naphthol.

[0031] The aforementioned component (b) may also include other phenolic resins and bisphenols described later.

[0032] The aforementioned component (c) has a structure derived from an aromatic carboxylic acid compound or an aromatic carboxylic acid halide compound. The aromatic carboxylic acid compound may contain one carboxyl group per molecule, but it is preferable to contain two or more carboxyl groups per molecule, and it is particularly preferable to contain two carboxyl groups per molecule. Furthermore, it is preferable that the carboxyl group is directly bonded to the aromatic ring. Specifically, examples include, but are not limited to, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4'-biphenylcarboxylic acid, 3,4'-biphenylcarboxylic acid, 3,3'-biphenylcarboxylic acid, 2,4'-biphenylcarboxylic acid, 2,3'-biphenylcarboxylic acid, 2,2'-biphenylcarboxylic acid, 1,3,5-benzenetricarboxylic acid and acid halide compounds thereof.

[0033] Polycondensation reactions may proceed without a solvent, or in an organic solvent. Examples of solvents that can be used include aromatic solvents such as toluene and xylene, aliphatic solvents such as cyclohexane and n-hexane, ethers such as diethyl ether and diisopropyl ether, ester solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate, ketone solvents such as acetone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone, carbitol solvents such as cellosolve and butyl carbitol, amide solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, and N-methyl-2-pyrrolidone, dimethyl sulfone, dimethyl sulfoxide, and 1,3-dimethyl-2-2-imidazolidinone, but are not limited to these, and two or more solvents may be used in combination.

[0034] Bases may be used in polycondensation reactions. Examples of bases include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as potassium carbonate, and tertiary amines such as triethylamine, pyridine, and N,N-dimethyl-4-aminopyridine (DMAP). Two or more bases may be used in combination.

[0035] In polycondensation reactions, condensing agents and phase transfer catalysts may also be used. Examples of condensing agents and phase transfer catalysts include alkylammonium salts and crown ethers, but are not limited to these; any conventionally known condensing agents and catalysts that can be used in esterification reactions may be used. These may be used individually or in combination of two or more types.

[0036] The reaction temperature is not particularly limited as long as the polycondensation reaction proceeds, but it is preferably 0 to 120°C, more preferably 0 to 100°C, and even more preferably 0 to 80°C. Above 120°C, hydrolysis of the active ester resin may proceed, potentially generating by-products. Below 0°C, the reaction may not proceed sufficiently.

[0037] The activated ester resin may be purified after the polycondensation reaction. For example, an alcohol compound or water may be added to the reaction solution to recover the target product as crystals. Alternatively, the obtained reaction solution or crystals may be redissolved in any solvent and an extraction process may be carried out. After the extraction process, purification treatments such as washing with water and microfiltration may be performed to remove by-product salts and excess starting materials from the system. Specifically, the amount of water necessary to dissolve the by-product salts is mixed, and the aqueous layer is removed by standing liquid-liquid separation. If necessary, an acid is added to neutralize the mixture, and washing with water is repeated. After that, the activated ester resin can be obtained by removing impurities through a dehydration process using a dehydrating agent or azeotrope and microfiltration, and then, if necessary, by distillation to remove the organic solvent. The organic solvent may be used as a solvent in the resin composition without completely removing it.

[0038] [Epoxy resin] The curable resin composition of this embodiment contains an epoxy resin. 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.

[0039] Examples of liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, glycidylamine type epoxy resin, and epoxy resin having a butadiene structure. Specific examples include "RE310S", "RE410S" (both manufactured by Nippon Kayaku Co., Ltd., bisphenol A type epoxy resin), "RE303S", "RE304S", "RE403S", "RE404S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy resin), "HP-4032", "HP-4032D", "HP-4032SS" (all manufactured by DIC Corporation, naphthalene type epoxy resin), "jER(registered trademark)828US", "jER828EL", "jER825", "jER828EL" (all manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin), "jER807", "jER1750" (both manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin), and "jER152" (manufactured by Mitsubishi Chemical Corporation, phenol Examples include novolac-type epoxy resins, "jER630", "jER630LSD" (both manufactured by Mitsubishi Chemical Corporation, glycidylamine-type epoxy resins), "ZX1059" (manufactured by Nippon Steel Chemical & Material Corporation, 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 (registered trademark) 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 Chemical & Material Corporation, liquid 1,4-glycidylcyclohexane-type epoxy resins), etc. These may be used individually or in combination of two or more types.

[0040] 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, naphthalene-type epoxy resin), "HP-4700", "HP-4710" (both manufactured by DIC, naphthalene-type tetrafunctional epoxy resins), "N-690" (manufactured by DIC, cresol novolac-type epoxy resin), "N-695" (manufactured by DIC, cresol novolac-type epoxy resin), "HP-7200" (manufactured by DIC, dicyclopentadiene-type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (all manufactured by DIC, dicyclopentadiene-type epoxy resins), "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP-6000" (all manufactured by DIC Corporation, naphthylene ether type epoxy resin), "EPPN-502H" (manufactured by Nippon Kayaku Co., Ltd., trisphenol type epoxy resin), "NC-7000L", "NC-7300" (both manufactured by Nippon Kayaku Co., Ltd., naphthol-cresol novolac type epoxy resin), "NC-3000H", "NC-3000", "NC-3000L", "NC-3100" (all manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin) Epoxy resins), "XD-1000-2L", "XD-1000-L", "XD-1000-H", "XD-1000-H" (all manufactured by Nippon Kayaku Co., Ltd., dicyclopentadiene type epoxy resin), "ESN475V" (manufactured by Nippon Steel Chemical & Material Co., Ltd., naphthol type epoxy resin), "ESN485" (manufactured by Nippon Steel Chemical & Material Co., Ltd., naphthol novolac type epoxy resin), "YX-4000H", "YX-4000", "YL6121" (all manufactured by Mitsubishi Chemical Corporation, biphenyl type epoxy resin), "YX-4000HK" (manufactured by Mitsubishi Chemical Corporation, biphenyl type epoxy resin) Examples include xylenol-type epoxy resin, "YX-8800" (manufactured by Mitsubishi Chemical Corporation, anthracene-type epoxy resin), "PG-100", "CG-500" (manufactured by Osaka Gas Chemical Co., Ltd., fluorene-based epoxy resin), "YL-7760" (manufactured by Mitsubishi Chemical Corporation, bisphenol AF-type epoxy resin), "YL-7800" (manufactured by Mitsubishi Chemical Corporation, fluorene-type epoxy resin), "jER1010" (manufactured by Mitsubishi Chemical Corporation, solid bisphenol A-type epoxy resin), and "jER1031S" (manufactured by Mitsubishi Chemical Corporation, tetraphenylethane-type epoxy resin).These may be used individually or in combination of two or more types.

[0041] The epoxy resin used in the curable resin composition of this embodiment preferably contains an epoxy resin with an epoxy equivalent of 250 g / eq. or more. When multiple epoxy resins are used, it is preferable that the epoxy resin with an epoxy equivalent of 250 g / eq. or more constitutes 20% by mass or more of the total amount of epoxy resin, more preferably 40% by mass or more, and particularly preferably 60% by mass or more. The upper limit of the content is within the above range, resulting in excellent dielectric properties.

[0042] In the curable resin composition of this embodiment, the mixing ratio f of the active ester resin and epoxy resin represented by formula (1) is represented by the following formula (A), and the mixing ratio f is preferably 0.9 to 3.0, more preferably 1.25 to 2.5, and particularly preferably 1.5 to 2.0. Mixing ratio f = (Amount of activated ester resin / Ester equivalent of activated ester resin) / (Amount of epoxy resin / Epoxy equivalent of epoxy resin) ... (A)

[0043] When the mixing ratio f is within the above range, the curability and dielectric properties are good, and it is highly elastic at around room temperature (25°C), and becomes less elastic at around 260°C during solder reflow, thereby reducing the warping of the substrate due to stress relaxation. When using the activated ester compound described later in combination, it is preferable to calculate the amount to be added while also considering the ester equivalent of the activated ester resin represented by formula (1) above and adjust it to the above range.

[0044] The curable resin composition of this embodiment can be further improved in performance by adding various materials.

[0045] [Curing accelerator] The curable resin composition of this embodiment can also have its curability improved by adding a curing accelerator. Preferred curing accelerators are anionic curing accelerators that promote the curing reaction by generating anions upon irradiation with ultraviolet light or visible light or by heating, or cationic curing accelerators that promote the curing reaction by generating cations upon irradiation with ultraviolet light or visible light or by heating.

[0046] Examples of anionic curing accelerators include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole; trialkylamines such as triethylamine and tributylamine; 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene, with 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene being preferred. Other examples include phosphines such as triphenylphosphine, tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, and quaternary ammonium salts such as hexadecyltrimethylammonium hydroxide, but are not limited to these. These can be used individually or in combination.

[0047] Examples of cationic curing accelerators include quaternary phosphonium salts such as triphenylbenzylphosphonium salt, triphenylethylphosphonium salt, and tetrabutylphosphonium salt (the counterions of the quaternary salts are halogens, organic acid ions, hydroxide ions, etc., with no particular preference, but organic acid ions and hydroxide ions are particularly preferred), tin octoate, zinc carboxylates (zinc 2-ethylhexanoate, zinc stearate, zinc behenate, zinc myristate), and zinc phosphate esters (zinc octyl phosphate, zinc stearyl phosphate), but are not limited to these. Furthermore, these may be used individually or in combination of multiple types.

[0048] The amount of curing accelerator added is 0.01 to 5.0 parts by mass per 100 parts by mass of the curable resin composition, as needed. The curing accelerator is preferably an anionic curing accelerator, and is preferably one or more of the following: imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, 4-dimethylaminopyridine, and 1,8-diazabicyclo(5,4,0)-undecene, with one or more of the imidazoles and dimethylaminopyridine being particularly preferred. The amount (α) of the anionic curing accelerator added is particularly preferably 0.98 ≤ α < 2.0 parts by mass per 100 parts by mass of the active ester resin in this embodiment, from the viewpoint of curability, heat resistance, and dielectric properties.

[0049] [Inorganic fillers] 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.

[0050] When obtaining a curable resin composition for semiconductor encapsulation, the amount of inorganic filler used is preferably 80 to 92 parts by mass, and more preferably 83 to 90 parts by mass, per 100 parts by mass of the curable resin composition. Unless otherwise specified, the 100 parts by mass of the curable resin composition does not contain solvent. Furthermore, when obtaining a curable resin composition for interlayer insulating layer forming materials, copper-clad laminates and prepregs, and substrate materials such as RCC (Resin Coated Copper), the amount of the above-mentioned inorganic filler used is preferably 5 to 80 parts by mass, and more preferably 10 to 60 parts by mass, per 100 parts by mass of the curable resin composition.

[0051] [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 both curability and appropriate stability. A radical polymerization initiator is a compound that generates radicals upon irradiation with ultraviolet or visible light or heating, thereby initiating a chain polymerization reaction. 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 less influence on curing temperature control, outgassing suppression, and the electrical properties of decomposition products.

[0052] 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 such substances include 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, but are not limited to these. Furthermore, these may be used individually or in combination. 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.

[0053] 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.

[0054] 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, dielectric properties such as dielectric constant and dielectric loss tangent may be impaired.

[0055] [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 of glass cloth and the like, and facilitates B-stage processes such as prepreg formation. If the polymerization reaction proceeds too far during prepreg formation, problems such as difficulty in lamination during the lamination process are likely to occur.

[0056] The polymerization inhibitor is present in an amount of 0.008 to 1 part by mass, preferably 0.01 to 0.5 parts by mass, per 100 parts by mass of the curable resin composition of this embodiment.

[0057] 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 embodiment.

[0058] 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] [T], N,N'-Hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 3,9-bis[1,1-dimethyl-2-{β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane, bis(3,5-di-t- Bisphenols such as calcium ethyl hydroxybenzylsulfonate, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, tris-(3,Examples 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.

[0059] 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.

[0060] 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, 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.

[0061] Examples of the above hindered amine polymerization inhibitors include ADEKA® LA-40MP, ADEKA® LA-40Si, ADEKA® LA-402AF, ADEKA® LA-87, ADEKA® LA-82, ADEKA® LA-81, ADEKA® LA-77Y, ADEKA® LA-77G, ADEKA® LA-72, ADEKA® LA-68, ADEKA® LA-63P, ADEKA® LA-57, and ADEKA® LA-52 (all manufactured by ADEKA Corporation). Examples include, but are not limited to, Chimassorb® 2020FDL, Chimassorb 944FDL, Chimassorb 944LD, Tinuvin® 622SF, Tinuvin PA144, Tinuvin 765, Tinuvin 770DF, Tinuvin XT55FB, Tinuvin 111FDL, Tinuvin 783FDL, and Tinuvin 791FB (all manufactured by BASF).

[0062] 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.

[0063] 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.

[0064] [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.

[0065] The phosphorus-based flame retardants mentioned above may be reactive or additive types. Specific examples include phosphorus 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 aforementioned phosphanes; and red phosphorus, but are not limited to these. Furthermore, these may be used individually or in combination of multiple types. Among 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.

[0066] The flame retardant content is preferably in the range of 0.1 to 0.6 parts by mass per 100 parts by mass of the curable resin composition. If the content is less than 0.1 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 hygroscopicity and dielectric properties of the cured product.

[0067] [Light stabilizer] The curable resin composition of this embodiment may also contain a light stabilizer. Suitable light stabilizers include hindered amine light stabilizers (HALS). 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-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine succinate, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], bis(1,2 Examples include, but are not limited to, 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, and 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.

[0068] The amount of light stabilizer is preferably in the range of 0.001 to 0.1 parts by mass per 100 parts by mass of the curable resin composition. 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 hygroscopicity and dielectric properties of the cured product.

[0069] [Binder resin] The curable resin composition of this embodiment may also use a binder resin. Examples of binder resins include, but are not limited to, but include butyral resins, acetal resins, acrylic resins, epoxy-nylon resins, NBR-phenolic resins, epoxy-NBR resins, and silicone resins. Furthermore, these may be used individually or in combination of multiple types.

[0070] 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, and is preferably 0.05 to 50 parts by mass per 100 parts by mass of the curable resin composition, and more preferably 0.05 to 20 parts by mass as needed.

[0071] [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.

[0072] The amount of additive added is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less, per 100 parts by mass of the curable resin composition.

[0073] The curable resin composition of this embodiment may further contain active ester resins other than the active ester resin of formula (1) above, phenolic resins, polyphenylene ether compounds, amine resins, compounds having ethylenically unsaturated bonds, isocyanate resins, polyamide resins, maleimide compounds, cyanate ester resins, polyimide resins, polybutadiene and its modified counterparts, polystyrene and its modified counterparts, polyethylene and its modified counterparts, benzoxazine compounds, etc., and these may be used individually or in combination of multiple types. Among these compounds, it is preferable to include polyphenylene ether compounds, compounds having ethylenically unsaturated bonds, cyanate ester resins, polybutadiene and its modified counterparts, polystyrene and its modified counterparts, in order to balance heat resistance, adhesion, and dielectric properties. By including these compounds, the brittleness of the cured product can be improved and adhesion to metal can be enhanced, and cracks in the package can be suppressed during reliability tests such as solder reflow and thermal cycling. The total amount of the above compounds used is preferably 10 times or less by mass, more preferably 5 times or less by mass, and most preferably 3 times or less by mass, relative to the active ester resin of this embodiment, unless otherwise specified. Furthermore, the preferred lower limit is 0.1 times or more by mass, more preferably 0.25 times or more by mass, and even more preferably 0.5 times or more by mass. Within this range, the effects of each added compound can be enhanced while taking advantage of the low dielectric properties of the compounds of this embodiment. Examples of these components can be used as shown below.

[0074] [Activated ester resins other than the activated ester resin of this embodiment] An active ester resin is a compound that contains at least one ester bond in its structure, with aliphatic chains, aliphatic rings, or aromatic rings bonded to both sides of the ester bond. Examples of active ester resins include compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. These are obtained by a condensation reaction between at least one compound of a carboxylic acid compound, an acid chloride, or a thiocarboxylic acid compound and at least one compound of a hydroxy compound or a thiol compound. In particular, from the viewpoint of improving heat resistance, it is preferable that the active ester resin is obtained from a carboxylic acid compound or an acid chloride and a hydroxy compound, and phenol compounds or naphthol compounds are preferred as the hydroxy compound. Active ester resins may be used alone or in combination of two or more types.

[0075] 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.

[0076] Examples of the above-mentioned acid chlorides include acetyl chloride, acrylate chloride, methacrylate chloride, malonyl chloride, succinate dichloride, diglycolyl chloride, glutarate dichloride, suberic acid 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.

[0077] 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.

[0078] 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 compounds 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.

[0079] Examples of commercially available active ester compounds include, for example, "EXB9451," "EXB9460," "EXB9460S," "HPC-8000-65T," "HPC-8000H-65TM," "EXB-8000L-65TM," and "EXB-8150-65T" (manufactured by DIC Corporation) as active ester compounds containing a dicyclopentadiene-type diphenol structure; "EXB9416-70BK" (manufactured by DIC Corporation) as an active ester compound containing a naphthalene structure; "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing an acetylated phenol novolac; "YLH1026," "YLH1030," and "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester compounds containing a benzoylated phenol novolac; and "EXB-9050L-62M" (manufactured by DIC Corporation) as a phosphorus atom-containing active ester curing agent.

[0080] [Phenolic resin] Phenolic resins are compounds having two or more phenolic hydroxyl groups in their molecule. Examples of phenolic resins include, but are not limited to, reaction products of phenols and aldehydes, reaction products of phenols and diene compounds, reaction products of phenols and ketones, reaction products of phenols and substituted biphenyls, reaction products of phenols and substituted phenyls, and reaction products of bisphenols and aldehydes. Furthermore, these can be used individually or in combination of multiple types. Specific examples of each of the above ingredients are given below, but this list is not exhaustive. <Phenols> Phenols, alkyl-substituted phenols, aromatic-substituted phenols, hydroquinones, resorcinols, naphthols, alkyl-substituted naphthols, dihydroxybenzenes, alkyl-substituted dihydroxybenzenes, dihydroxynaphthalenes, etc. <Aldehydes> Formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, biphenylaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural, etc. <Diene compounds> Dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, diisopropenylbenzene, butadiene, isoprene, etc. <Ketones> Acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, indanone, fluorenone, etc. <Substituted biphenyls> 4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, 4,4'-bis(hydroxymethyl)-1,1'-biphenyl, etc. <Substituted Phenyl Groups> 1,4-bis(chloromethyl)benzene, 1,3-bis(chloromethyl)benzene, 1,2-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, 1,3-bis(methoxymethyl)benzene, 1,2-bis(methoxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene, 1,3-bis(hydroxymethyl)benzene, 1,2-bis(hydroxymethyl)benzene, α,α,α',α'-tetramethyl-1,4-benzenedimethanol, α,α,α',α'-tetramethyl-1,3-benzenedimethanol, α,α,α',α'-tetramethyl-1,2-benzenedimethanol, etc.

[0081] [Polyphenylene ether compounds] From the viewpoint of heat resistance and electrical properties, the polyphenylene ether compound is preferably a polyphenylene ether compound having an ethylenically unsaturated bond, and more preferably a polyphenylene ether compound having an acrylic group, a methacrylic group, or a styrene structure. Examples of commercially available products include SA-9000 (manufactured by SABIC, a polyphenylene ether compound having a methacrylic group) and OPE-2St 1200 (manufactured by Mitsubishi Gas Chemical Company, a polyphenylene ether compound having a styrene structure). The number-average molecular weight (Mn) of the polyphenylene ether compound is preferably 500 to 5000, more preferably 2000 to 5000, and even more preferably 2000 to 4000. If the number-average molecular weight is less than 500, the heat resistance of the cured product tends not to be sufficient. If the number-average molecular weight is greater than 5000, the melt viscosity increases, and sufficient fluidity cannot be obtained, which tends to lead to molding defects. Furthermore, the reactivity decreases, requiring a long time for the curing reaction, increasing the amount of unreacted material that is not incorporated into the curing system, 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 achieve excellent heat resistance and moldability while maintaining excellent dielectric properties. Specifically, the number-average molecular weight can be measured using methods such as gel permeation chromatography.

[0082] 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 approximately 10,000 to 30,000. Alternatively, these may be used as raw materials and reacted with compounds having ethylenically unsaturated bonds, such as methacrylate chloride, acrylate 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 maintain even higher heat resistance due to having hydroxyl groups derived from phenolic compounds that contribute to curing at both ends of the molecular chain, and because functional groups can be introduced to both ends of the molecular chain even after modification with compounds having ethylenically unsaturated bonds. Furthermore, polyphenylene ether compounds obtained by polymerization reactions are preferable because they exhibit excellent fluidity.

[0083] The molecular weight of polyphenylene ether compounds can be adjusted by adjusting polymerization conditions, etc., in the case of polyphenylene ether compounds obtained by polymerization reactions. In the case of polyphenylene ether compounds obtained by redistribution reactions, the molecular weight of the resulting polyphenylene ether compound can be adjusted by adjusting the conditions of the redistribution reaction, etc. More specifically, this can be done by adjusting the amount of phenolic compound used in the redistribution reaction. That is, the higher the amount of phenolic compound used, the lower the molecular weight of the resulting polyphenylene ether compound. In this case, poly(2,6-dimethyl-1,4-phenylene ether) can be used as the high molecular weight polyphenylene ether compound that undergoes the redistribution reaction. Furthermore, the phenolic compound used in the redistribution reaction is not particularly limited, but polyfunctional phenolic compounds having two or more phenolic hydroxyl groups in the molecule, such as bisphenol A, phenol novolac, and cresol novolac, are preferably used. These may be used individually or in combination of two or more.

[0084] 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, per 100 parts by mass of the curable resin composition. When the content of the polyphenylene ether compound is within the above range, it is preferable not only to obtain a cured product that is excellent in heat resistance and the like, but also in that the excellent dielectric properties of the polyphenylene ether compound are fully exhibited.

[0085] [Amine resin] Amine resins are compounds that have two or more amino groups in their molecule. For example, diaminodiphenylmethane, diaminodiphenylsulfone, isophoronediamine, naphthalenediamine, aniline novolac (reaction product of aniline and formalin), N-methylaniline novolac (reaction product of N-methylaniline and formalin), orthoethylaniline novolac (reaction product of orthoethylaniline and formalin), reaction product of 2-methylaniline and formalin, reaction product of 2,6-diisopropylaniline and formalin, reaction product of 2,6-diethylaniline and formalin, reaction product of 2-ethyl-6-ethylaniline and formalin, reaction product of 2,6-dimethylaniline and formalin, and aniline obtained by reaction of aniline with xylylene chloride. Examples of such materials include, but are not limited to, resins, reaction products of aniline and substituted biphenyls (such as 4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl) as described in Japanese Patent Publication No. 6429862, reaction products of aniline and substituted phenyls (such as 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene), 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, reaction products of aniline and diisopropenylbenzene, and dimer amines. Furthermore, these may be used individually or in combination of multiple materials.

[0086] [Compounds containing ethylenically unsaturated bonds] A compound containing an ethylenically unsaturated bond is a compound that has one or more ethylenically unsaturated bonds in its 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 the reaction products of the phenol resin and halogenated compounds containing ethylenically unsaturated bonds (chloromethylstyrene, allyl chloride, methallyl chloride, acrylate chloride, methacrylate chloride, etc.), and phenols containing ethylenically unsaturated bonds (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) and halogenated compounds (1,4-bis(chloromethyl)benzyl Reaction products of 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, poly(arylene ether) polymers (HC-G0037, HC-G0024, HC-G0030, HC-G0038, all manufactured by JSR Corporation. These are pyridazine, pyrimidine or (May contain monomer units containing a pyrazine group.) Reaction products of fluorenes or indenes with halogenated compounds containing ethylenically unsaturated bonds (chloromethylstyrene, allyl chloride, metharyl chloride, acrylate chloride, methacrylate chloride, etc.), compounds described in Japanese Patent No. 6951829, copolymers containing divinylbenzene as a constituent unit (ODV-XET(X3), ODV-XET(X4), ODV-XET(X5), all manufactured by Nippon Steel Chemical & Material Co., Ltd.), styrene, vinylitol Examples include, but are not limited to, ethyl vinylbenzene, vinyl naphthalene, vinyl biphenyl, vinyl fluorene, divinylbenzene, divinyl naphthalene, divinyl biphenyl, divinyl fluorene, BVPM (bis(vinylphenyl)methane), BVPE (bis(vinylphenyl)ethane), BVPH (bis(vinylphenyl)hexane), trivinylcyclohexane, and thermosetting cycloolefin copolymers (Mitsui Chemicals: GigaFreak, Zeon Corporation: TU-01A). These can be used individually or in combination.

[0087] [Isocyanate resin] Isocyanate resins are compounds that have two or more isocyanate groups in their 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, norbornenediisocyanate, and lysinediisocyanate; biuret compounds of one or more isocyanate monomers; or isocyanates 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.

[0088] [Polyamide resin] 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 can be used individually or in combination. Specific examples of each of the above ingredients are given below, but this list is not exhaustive. <Diamine> Ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-diaminopentane, 2-methyl 1,8-diaminooctane, dimeramine, 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. <Diisocyanate> Benzene diisocyanate, toluene diisocyanate, 1,3-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)cyclohexane, bis(4-isocyanatophenyl)methane, isophorone diisocyanate, 1,3-bis(2-isocyanato-2-propyl)benzene, 2,2-bis(4-isocyanatophenyl)hexafluoropropane, dicyclohexylmethane-4,4'-diisocyanate, etc. <Dicarboxylic acid> 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, dodecanediol dichloride, azera oil chloride, 2,5-franzicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesinate chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, 4,4'-azodibenzoyl dichloride, etc. <Lactam> ε-caprolactam, ω-undecanlactam, ω-laurolactam, etc.

[0089] [Polyimide resin] Examples of polyimide resins include, but are not limited to, the reaction products of the diamine and the tetracarboxylic dianhydrides exemplified below. Furthermore, these can be used individually or in combination. <Tetracarboxylic acid dianhydride> 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methylcyclohexene-1,2-dicarboxylic acid anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 2,2',3,3'-benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 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]meth 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 dianhydride, 2,3,6,7-Anthracenetetracarboxylic dianhydride, 1,2,7,8-Phenanthrenetetracarboxylic dianhydride, Ethylenetetracarboxylic dianhydride, 1,2,3,4-Butanetetracarboxylic dianhydride, 1,2,3,4-Cyclobutanetetracarboxylic dianhydride, Cyclopentanetetracarboxylic dianhydride, Cyclohexane-1,2,3,4-Tetocarboxylic dianhydride, Cyclohexane-1,2,4,5-Tetocarboxylic dianhydride Dianhydride of 3,3',4,4'-bicyclohexyltetracarboxylic acid 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, 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, 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.

[0090] [Maleimide compounds] Maleimide compounds are compounds that have 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)benzene, and Zylok-type maleimide compounds (anilix). Maleimide (manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenylaralkyl type maleimide compound (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 compound 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 2019 "~Continued Epoxy Resin CAS Number Story~ Curing Agent CAS Number Memo No. 32" Examples include, but are not limited to, the maleimide compounds listed in "Bismaleimide (2)". Furthermore, these may be used individually or in combination.

[0091] [Cyanate ester resin] Cyanate ester resins are cyanate ester compounds obtained by reacting phenol resins with cyanide halides. Specific examples include, but are not limited to, dicyanatebenzene, tricyanatebenzene, dicyanatenaphthalene, dicyanatebiphenyl, 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. These compounds may be used individually or in combination. Furthermore, the cyanate ester compound whose synthesis method is described in Japanese Patent Publication No. 2005-264154 is particularly preferred as a cyanate ester compound because it has excellent low hygroscopicity, flame retardancy, and dielectric properties. Cyanate ester resins may also contain catalysts such as zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octoate, tin octoate, lead acetylacetonate, and dibutyltin maleate to trimerize the cyanate groups as needed and form sym-triazine rings.

[0092] It is preferable to use 0.0001 to 0.10 parts by mass, preferably 0.00015 to 0.0015 parts by mass, of the catalyst per 100 parts by mass of the cyanate ester resin and the curable resin composition.

[0093] [Polybutadiene and its modified forms] Polybutadiene and its modified products are compounds that contain 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. 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.), while 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 volatilization rate is high, making it difficult to adjust the solid content during prepreg preparation, and above the upper limit of the above range, compatibility with other curable resins deteriorates. Generally, in the case of compounds containing heteroatoms such as oxygen and nitrogen, such as bismaleimide and polymaleimide, it is difficult to ensure compatibility with low-polarity compounds such as compounds composed mainly of hydrocarbons or compounds composed only of hydrocarbons, due to their polarity. On the other hand, the compound of this embodiment does not have a framework design that actively incorporates heteroatoms such as oxygen and nitrogen, and therefore exhibits excellent compatibility with materials that have low polarity and low dielectric properties, as well as compounds composed only of hydrocarbons.

[0094] [Polystyrene and its modified forms] Polystyrene and its modified products are compounds that have polystyrene or a structure derived from polystyrene within their molecule. 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.), SEEPS (styrene-ethylene / ethylene-propylene-styrene block copolymer: Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099, all manufactured by Kuraray Co., Ltd.), and SEBS (styrene-ethylene-butylene-styrene). Examples of block copolymers include, but are not limited to, Septon 8004, Septon 8006, Septon 8007L (all manufactured by Kuraray Co., Ltd.), SEEPS-OH (a compound having hydroxyl groups at the ends of styrene-ethylene / ethylene-propylene-styrene block copolymers: Septon HG252, manufactured by Kuraray Co., Ltd.), SIS (styrene-isoprene-styrene block copolymers: Septon 5125, Septon 5127, both manufactured by Kuraray Co., Ltd.), Hydrogenated SIS (hydrogenated styrene-isoprene-styrene block copolymers: Hybler® 7125F, Hybler 7311F, both manufactured by Kuraray Co., Ltd.), SIBS (styrene-isobutylene-styrene block copolymers: SIBSTAR® 073T, SIBSTAR 102T, SIBSTAR 103T (all manufactured by Kaneka Corporation), Septon V9827 (manufactured by Kuraray Co., Ltd.)), etc. Furthermore, these can be used individually or in combination of multiple types. Polystyrene and its modified products are preferable to be those without unsaturated bonds, as they have higher heat resistance and are less susceptible to oxidative degradation. In addition, 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, but 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 it be around 10,000 to 300,000.

[0095] [Polyethylene and its modified forms] Polyethylene and its modified products refer to polyethylene or compounds having a polyethylene-derived structure within their molecules. Examples of polyethylene and its modified products include, but are not limited to, ethylene-propylene copolymers, ethylene-styrene copolymers, ethylene-propylene-ethylidene norbornene copolymers (Mitsui Chemicals EBT: K-8370EM, K-9330M, etc.), ethylene-propylene-vinyl norbornene copolymers (Mitsui Chemicals 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 or 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.

[0096] [Benzoxazine compounds] As the benzoxazine compound, any compound obtained by reacting a compound having a phenolic hydroxyl group, a compound having an amino group, or a compound having an aldehyde group may be used. The compound having a phenolic hydroxyl group is not particularly limited, but for example, the aforementioned phenolic resins, phenols (which may have substituents such as alkenyl groups or alkyl groups), and bisphenols can be used. The compound having an amino group is not particularly limited, but for example, the aforementioned amine resins, diamines, and anilines (which may have substituents such as alkenyl groups or alkyl groups) can be used. As the aldehyde compound, for example, the aforementioned aldehydes can be used, but formaldehyde is preferred. Commercially available benzoxazine compounds may be used, including benzoxazine Pd, Fa, ALP-d (all manufactured by Shikoku Chemicals Co., Ltd.), JBZ-BA100N, JBZ-FA100N, JBZ-DP100N, JBZ-OP100N, JBZ-OP100D, JBZ-OP100I (all manufactured by JFE Chemical Corporation), and BTBz (manufactured by Nippon Materials Technology Co., Ltd.).

[0097] The curable resin composition of this embodiment is obtained by preparing the above components in predetermined proportions, pre-curing at 130-180°C for 30-500 seconds, and then post-curing at 150-200°C for 2-15 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.

[0098] The method for preparing the curable resin composition of this embodiment is not particularly limited, but may be done by simply mixing each component uniformly or by prepolymerization. For example, prepolymerization can be performed by heating a mixture containing the compounds of this embodiment in the presence or absence of a curing accelerator and polymerization initiator, in the presence or absence of a solvent. Similarly, prepolymerization may be performed by adding compounds such as amine compounds, compounds having ethylenically unsaturated bonds, maleimide compounds, cyanate ester compounds, polybutadiene and its modified products, polystyrene and its modified products, inorganic fillers, and other additives. Mixing or prepolymerization of each component can be performed using, for example, an extruder, kneader, or roll in the absence of a solvent, and a reaction vessel with a stirring device can be used in the presence of a solvent.

[0099] For uniform mixing, the resin composition is kneaded using equipment such as a kneader, roll, or planetary mixer at a temperature in the range of 50 to 100°C. After pulverization, the resulting resin composition can be molded into cylindrical tablets using a molding machine such as a tablet machine, or into granular powder or powdered 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 produce curable resin composition molded bodies. The resulting molded bodies are non-sticky at 0 to 20°C and maintain almost no decrease in fluidity or curability even after storage at -25 to 0°C for more than a week. The resulting molded body can be molded into a hardened product using a transfer molding machine or a compression molding machine.

[0100] The curable resin composition of this embodiment can also be converted into a varnish-like composition (hereinafter simply referred to as varnish) by adding an organic solvent. The curable resin composition of this embodiment can be dissolved in a solvent such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, or N-methylpyrrolidone as needed to form a varnish, which can then be impregnated into a substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, or paper, and heated and dried to obtain a prepreg. The resulting prepreg can then be hot-press molded to obtain a cured product of the curable resin composition of this embodiment. In this case, the solvent used should account for 10 to 70% by mass, preferably 15 to 70% by mass, of the mixture of the curable resin composition of this embodiment and the solvent. Alternatively, if the composition is in liquid form, a cured resin product containing carbon fibers can be obtained directly, for example, by the RTM method.

[0101] 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 varnish onto a release film, removing the solvent under heating, and then performing the B-stage process. This sheet-like adhesive can be used as an interlayer insulating layer in multilayer substrates and the like.

[0102] 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 fiber. 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 the reinforcing fibers with the varnish and then heating and drying them.

[0103] 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 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.

[0104] 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), dry it, and then form a resin composition layer on the support film. When the curable resin composition of this embodiment is used 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 each component 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.

[0105] 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. It is preferable to be able to fill the holes 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.

[0106] A specific method for manufacturing the aforementioned 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).

[0107] 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 the organic solvent in a proportion such that the non-volatile content is 30 to 60% by mass of the total.

[0108] Furthermore, the thickness of the formed resin composition layer (X) must be greater than or equal to the thickness of the conductive layer of the circuit board to which the resin composition layer (X) is laminated. Since the thickness of the conductive 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 this embodiment 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 (X) and to prevent scratches.

[0109] The 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.

[0110] The support film (Y) is peeled off after the resin composition layer (X) is laminated to the circuit board, or after an insulating layer is formed by heat curing the resin composition layer (X). If the support film (Y) is peeled off after the resin composition layer (X) 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 the support film (Y) is peeled off after the resin composition layer (X) has been cured, the support film (Y) is subjected to a release treatment beforehand.

[0111] 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, the protective film is peeled off from the resin composition layer (X), 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 type or continuous type using a roll. In addition, 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 × 10 4 ~107.9×10 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.

[0112] 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).

[0113] 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 this embodiment exhibits excellent heat resistance and dielectric properties, it is suitably used in electrical and electronic components such as encapsulants for semiconductor devices, encapsulants for liquid crystal display devices, encapsulants for organic EL devices, laminates (printed wiring boards, BGA (ball grid array) 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.

[0114] The curable resin of this embodiment has excellent mechanical properties, and the elastic modulus obtained in the DMA measurement described in the examples below preferably has a high maximum value near room temperature, while the elastic modulus in the high-temperature range preferably has a low value. Specifically, the maximum value of the elastic modulus is preferably 3000 MPa or more, more preferably 3200 MPa or more, even more preferably 3400 MPa or more, and particularly preferably 3500 MPa or more. Having an elastic modulus of 3000 MPa or more near room temperature makes it possible to obtain sufficient rigidity. The minimum value of the elastic modulus is preferably 100 MPa or less, more preferably 50 MPa or less, and even more preferably 30 MPa or less. The larger the value obtained by subtracting the elastic modulus in the high-temperature range from the elastic modulus near room temperature, the greater the effect of low warping due to stress relaxation. The value obtained by subtracting the minimum value of the elastic modulus from the maximum value of the elastic modulus is preferably 3000 MPa or more and 5000 MPa or less, more preferably 3500 MPa or more and 4500 MPa or less, and even more preferably 3800 MPa or more and 4200 MPa or less.

[0115] The curable resin of this embodiment has excellent heat resistance, and the glass transition temperature (Tg) obtained in the DMA measurement described in the examples below is preferably 150°C or higher, more preferably 155°C or higher, particularly preferably 160°C or higher, and most preferably 180°C or higher. The upper temperature limit is preferably 300°C or lower, more preferably 350°C or lower, particularly preferably 220°C or lower, and most preferably 200°C or lower. [Examples]

[0116] Next, the present invention will be described in more detail with reference to examples. Hereinafter, unless otherwise specified, parts refer to parts by mass. However, the present invention is not limited to these examples.

[0117] The various analytical methods used in the examples are described below. <Number average molecular weight (Mn), weight average molecular weight (Mw)> The calculation was performed using polystyrene standard solutions and converted to polystyrene equivalents. GPC: DGU-20A3R, LC-20AD, SIL-20AHT, RID-20A, SPD-20A, CTO-20A, CBM-20A (all manufactured by Shimadzu Corporation) Columns: Shodex KF-603, KF-602 x2, KF-601 x2) Linking eluent: tetrahydrofuran Flow rate: 0.5ml / min. Column temperature: 40℃ Detection: RI (Differential Refraction Detector)

[0118] [Synthesis Example 1] In a flask equipped with a thermometer, condenser, and stirrer, 204 parts of orthophenylphenol (Tokyo Chemical Co., Ltd.), 243.6 parts of isophthalic acid chloride (Tokyo Chemical Co., Ltd.), 3.6 parts of tetrabutylammonium bromide (Kanto Chemical Co., Ltd.), and 1200 parts of xylene were added and dissolved under nitrogen purging. In a separate container, 235.8 parts of N-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine were dissolved in 639.6 parts of 15% sodium hydroxide aqueous solution. This sodium hydroxide aqueous solution was added dropwise over 2 hours while stirring the previously prepared xylene solution, maintaining the system temperature below 35°C. After addition, the system temperature was raised to 65°C and stirring continued for 1 hour. After the reaction was complete, the organic layer was washed five times with 100 parts of water. The obtained solution was microfiltered to remove impurities, and then xylene was distilled under reduced pressure using a rotary evaporator to obtain 94.7 parts of the active ester resin (a-1) represented by the following formula (E1) as a solid resin (Mn: 1009, Mw: 1799). The GPC chart of the obtained compound is shown in Figure 1. The theoretical ester equivalent from the charging ratio of the raw materials was 248 g / eq., and the theoretical number of repeats n was 1. In the following formula (E1), the content of n=0 isomer was 22.7 area% as detected by differential refractometer detection in gel permeation chromatography (GPC), and the content of n=1 isomer was 26.9 area%.

[0119] [ka]

[0120] [Synthesis Example 2] In a flask equipped with a thermometer, condenser, and stirrer, 34 parts of orthophenylphenol (Tokyo Chemical Co., Ltd.), 35.5 parts of isophthalic acid chloride (Tokyo Chemical Co., Ltd.), 0.5 parts of tetrabutylammonium bromide (Kanto Chemical Co., Ltd.), and 200 parts of xylene were added and dissolved under nitrogen purging. In a separate container, 29.5 parts of N-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine were dissolved in 93.3 parts of 15% sodium hydroxide aqueous solution. This sodium hydroxide aqueous solution was added dropwise over 2 hours while stirring the previously prepared xylene solution, maintaining the system temperature below 35°C. After addition, the system temperature was raised to 65°C and stirring continued for 1 hour. After the reaction was complete, the organic layer was washed five times with 25 parts of water. The obtained solution was microfiltered to remove impurities, and then xylene was distilled under reduced pressure using a rotary evaporator to obtain 79.1 parts of the active ester resin (a-2) represented by the following formula (E2) as a solid resin (Mn: 864, Mw: 1490). The GPC chart of the obtained compound is shown in Figure 2. The theoretical ester equivalent from the charging ratio of the raw materials was 247 g / eq., and the theoretical number of repeats n was 0.75. In the following formula (E2), the content of n=0 isomer was 29.5 area% as detected by differential refractometer detection in gel permeation chromatography (GPC), and the content of n=1 isomer was 28.9 area%.

[0121] [ka]

[0122] [Synthesis Example 3] In a flask equipped with a thermometer, condenser, and stirrer, 13.6 parts of 2,3,6-trimethylphenol (Tokyo Chemical Co., Ltd.), 20.3 parts of isophthalic acid chloride (Tokyo Chemical Co., Ltd.), 0.2 parts of tetrabutylammonium bromide (Kanto Chemical Co., Ltd.), and 150 parts of toluene were added and dissolved under nitrogen purging. In a separate container, 19.7 parts of N-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine were dissolved in 53.3 parts of 15% sodium hydroxide aqueous solution. This sodium hydroxide aqueous solution was added dropwise over 2 hours while stirring the previously prepared toluene solution, maintaining the system temperature below 35°C. After addition, the system temperature was raised to 65°C and stirring continued for 1 hour. After the reaction was complete, the organic layer was washed five times with 25 parts of water. After removing impurities from the obtained solution by microfiltration, toluene was removed by vacuum distillation using a rotary evaporator to obtain 46.3 parts of the active ester resin (a-3) represented by the following formula (E3) as a solid resin (Mn: 1043, Mw: 1945). The GPC chart of the obtained compound is shown in Figure 3. The theoretical ester equivalent from the charging ratio of the raw materials was 231 g / eq., and the theoretical number of repeats n was 1. In the following formula (E3), the content of the n=0 isomer was 16.7 area% as detected by differential refractometer detection in gel permeation chromatography (GPC), and the content of the n=1 isomer was 22.8 area%.

[0123] [ka]

[0124] [Synthesis Example 4] In a flask equipped with a thermometer, condenser, and stirrer, 14.4 parts of 1-naphthol (Tokyo Chemical Co., Ltd.), 20.3 parts of isophthalic acid chloride (Tokyo Chemical Co., Ltd.), 0.3 parts of tetrabutylammonium bromide (Kanto Chemical Co., Ltd.), and 150 parts of toluene were added and dissolved under nitrogen purging. In a separate container, 19.7 parts of N-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine were dissolved in 53.3 parts of 15% sodium hydroxide aqueous solution. This sodium hydroxide aqueous solution was added dropwise over 2 hours while stirring the previously prepared toluene solution, maintaining the system temperature below 35°C. After addition, the system temperature was raised to 65°C and stirring continued for 1 hour. After the reaction was complete, the organic layer was washed five times with 100 parts of water. The obtained solution was microfiltered to remove impurities, and then xylene was distilled under reduced pressure using a rotary evaporator to obtain 46 parts of the active ester resin (a-4) represented by the following formula (E4) as a solid resin (Mn: 715, Mw: 1625). The GPC chart of the obtained compound is shown in Figure 4. The theoretical ester equivalent from the starting ratio of the raw materials was 235 g / eq., and the theoretical number of repeats n was 1. In the following formula (E4), the content of the n=0 isomer was 20.3 area% as detected by differential refractometer detection in gel permeation chromatography (GPC), and the content of the n=1 isomer was 28.3 area%.

[0125] [ka]

[0126] [Synthesis Example 5] While purging a flask equipped with a thermometer, condenser, and stirrer with nitrogen, 27.2 parts of 2,3,6-trimethylphenol (Tokyo Chemical Co., Ltd.), 20.3 parts of isophthalic acid chloride (Tokyo Chemical Co., Ltd.), 0.1 parts of tetrabutylammonium bromide (Kanto Chemical Co., Ltd.), and 100 parts of toluene were added and dissolved. Dissolved in 32 parts of 25% sodium hydroxide aqueous solution, and the previously prepared toluene solution was added dropwise over 2 hours while stirring, maintaining the system temperature below 35°C. After addition, the system temperature was raised to 65°C and stirring continued for 1 hour. After the reaction was complete, the organic layer was washed five times with 25 parts of water. After removing impurities from the obtained solution by microfiltration, toluene was distilled under reduced pressure using a rotary evaporator to obtain 46.3 parts of the active ester resin (a-5) represented by the following formula (E5) as a solid resin. The GPC chart of the obtained compound is shown in Figure 5. The theoretical ester equivalent from the starting ratio of the raw materials was 201 g / eq.

[0127] [ka]

[0128] [Examples 1-5, Comparative Example 1] <Specimen Preparation> The activated ester resins (E1-E5) obtained in Synthesis Examples 1-5, NC-3000-H epoxy resin (epoxy equivalent: 288 g / eq.), and dimethylaminopyridine (DMAP) as a curing accelerator were used in the amounts shown in Table 1. These were then vacuum-press molded while sandwiched between mirror-finish copper foil (T4X: manufactured by Fukuda Metal Copper Foil Co., Ltd.) and cured at 200°C for 2 hours. A 250 μm thick cushion paper with a 150 mm x 150 mm cutout in the center was used as a spacer. For evaluation, test pieces were cut to the desired size using a laser cutter as needed, and the evaluation was performed.

[0129] <Heat resistance (DMA)> Dynamic viscoelasticity measuring instrument: TA-instruments, DMA-2980 Measurement temperature range: 30~350℃ Heating rate: 2°C / min Frequency: 10Hz Test specimen size: A piece cut to 5mm x 50mm was used (thickness 0.2mm).

[0130] <Dielectric Loss Tangent Test> Tests were conducted using a 10GHz cavity resonator manufactured by AET Co., Ltd. at 25°C using the cavity resonator perturbation method. The sample size was 1.7 mm wide x 100 mm long with a thickness of 0.3 mm.

[0131] [Table 1]

[0132] The results in Table 1 confirm that the curable resin composition of the present invention exhibits excellent heat resistance, low dielectric properties, and mechanical properties.

[0133] [Note] As described above, this embodiment includes the following disclosures.

[0134] [1] A curable resin composition containing an active ester resin and an epoxy resin represented by the following formula (1).

[0135] [ka]

[0136] (In equation (1), the multiple X, Y, and Z each exist independently, X represents a divalent organic group represented by equation (2) below, Y represents a divalent organic group, and Z represents a monovalent organic group. n is the average value of the number of repetitions, and 0 <n≦20である。)

[0137] [ka]

[0138] (In formula (2), each of the multiple R's exists independently and represents a hydrocarbon group with 1 to 10 carbon atoms, a halogen atom, or an alkoxy group with 1 to 10 carbon atoms. m represents an integer from 0 to 4. * represents the bond position with the oxygen atom in formula (1).)

[0139] [2] The curable resin composition according to the preceding paragraph [1], wherein Y in formula (1) is one or more of optionally substituted phenylene, optionally substituted naphthylene, or optionally substituted biphenylene.

[0140] [3] The curable resin composition according to item [1] or [2] above, wherein Z in formula (1) is one or more of the following: a naphthyl group which may have a substituent, a biphenyl group which may have a substituent, and a phenyl group which may have a substituent.

[0141] [4] The curable resin composition according to item [1] or [2] above, wherein Z in formula (1) is a phenyl group which may have a substituent.

[0142] [5] A curable resin composition according to any one of the preceding items [1] to [4], wherein the mixing ratio f represented by the following formula (A) is 1.25 to 2.5. Mixing ratio f = (Amount of activated ester resin / Ester equivalent of activated ester resin) / (Amount of epoxy resin / Epoxy equivalent of epoxy resin) ... (A)

[0143] [6] A curable resin composition according to any one of the preceding paragraphs [1] to [5], wherein, in a measurement of the elastic modulus using a dynamic viscoelasticity measuring instrument in a temperature range of 30 to 350°C, the value obtained by subtracting the minimum elastic modulus from the maximum elastic modulus is 3800 MPa or more and 5000 MPa or less.

[0144] [7] A curable resin composition according to any one of the preceding paragraphs [1] to [6], wherein the number average molecular weight of the active ester resin represented by formula (1) is 600 or more and 1000 or less.

[0145] [8] A curable resin composition according to any one of the preceding paragraphs [1] to [7], further containing a curing accelerator.

[0146] [9] Furthermore, the curable resin composition according to any one of the preceding paragraphs [1] to [8], wherein it contains an inorganic filler, and the amount of the inorganic filler is 40% by mass or more of the total amount of the curable resin composition.

[0147]

[10] Furthermore, the curable resin composition according to any one of the preceding paragraphs [1] to [9] contains at least one selected from a polymerization initiator, an epoxy resin, an active ester resin other than the active ester resin represented by formula (1), a phenol resin, a polyphenylene ether compound, an amine resin, a compound having an ethylenically unsaturated bond, an isocyanate resin, a polyamide resin, a maleimide compound, a cyanate ester resin, a polyimide resin, a polybutadiene and a modified thereof, polystyrene and a modified thereof, polyethylene and a modified thereof, and a benzoxazine compound.

[0148]

[11] A cured product obtained by curing a curable resin composition described in any one of the preceding paragraphs [1] to

[10] . [Industrial applicability]

[0149] The curable resin composition and cured product of the present invention are suitably used in electrical and electronic components such as semiconductor encapsulants, printed circuit boards, build-up laminates, and optical waveguide devices.

Claims

1. A curable resin composition containing an active ester resin and an epoxy resin represented by the following formula (1). 【Chemistry 1】 (In equation (1), the multiple X, Y, and Z each exist independently. X represents a divalent organic group represented by equation (2) below, Y represents a divalent organic group, and Z represents a monovalent organic group. n is the average number of repetitions, where 0 < n ≤ 20.) 【Chemistry 2】 (In formula (2), each of the multiple R's exists independently and represents a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, or an alkoxy group having 1 to 10 carbon atoms. m represents an integer from 0 to 4. * represents the bond position with the oxygen atom in formula (1).)

2. The curable resin composition according to claim 1, wherein Y in formula (1) is one or more of optionally substituted phenylene, optionally substituted naphthylene, and optionally substituted biphenylene.

3. The curable resin composition according to claim 1, wherein Z in formula (1) is one or more of a naphthyl group which may have a substituent, a biphenyl group which may have a substituent, and a phenyl group which may have a substituent.

4. The curable resin composition according to claim 1, wherein Z in formula (1) is a phenyl group which may have a substituent.

5. The curable resin composition according to claim 1, wherein the mixing ratio f represented by the following formula (A) is 1.25 to 2.

5. Mixing ratio f = (Ester equivalent of activated ester resin × Amount of activated ester) / (Epoxy equivalent of epoxy resin × Amount of epoxy resin) ... (A)

6. The curable resin composition according to claim 1, wherein, in a measurement of the elastic modulus using a dynamic viscoelasticity measuring instrument in a temperature range of 30 to 350°C, the value obtained by subtracting the minimum elastic modulus from the maximum elastic modulus is 3800 MPa or more and 5000 MPa or less.

7. The curable resin composition according to claim 1, wherein the number average molecular weight of the active ester resin represented by formula (1) is 600 or more and 1000 or less.

8. The curable resin composition according to claim 1, further containing a curing accelerator.

9. Furthermore, the curable resin composition according to claim 1, wherein it contains an inorganic filler, and the amount of the inorganic filler is 40% by mass or more of the total amount of the curable resin composition.

10. Furthermore, the curable resin composition according to claim 1 contains at least one selected from a polymerization initiator, an epoxy resin, an active ester resin other than the active ester resin represented by formula (1), a phenol resin, a polyphenylene ether compound, an amine resin, a compound having an ethylenically unsaturated bond, an isocyanate resin, a polyamide resin, a maleimide compound, a cyanate ester resin, a polyimide resin, a polybutadiene and a modified thereof, polystyrene and a modified thereof, polyethylene and a modified thereof, and a benzoxazine compound.

11. A cured product obtained by curing a curable resin composition according to any one of claims 1 to 10.

Images