Active ester resin, curable resin composition, and cured product thereof

Abstract

The present invention provides an active ester resin, a curable resin composition, and a cured product thereof, which have a low softening point, excellent low dielectric properties, and heat resistance. [Solution] An activated ester resin (A) represented by the following formula (1). TIFF2026049623000020.tif19170 TIFF2026049623000021.tif32170 TIFF2026049623000022.tif46170 (In formula (1), X A represents the base expressed by equation (2), and X B X represents a group containing at least one aromatic ring. C (This represents the base expressed by equation (3).)

Description

[Technical Field]

[0001] This invention relates to an active ester resin, resin composition, and cured product thereof for epoxy resin curing agent applications, which achieve both outstanding dielectric properties and processability by containing specific molecular structural units and satisfying specific molecular weight conditions. It is suitably used in electrical and electronic components such as semiconductor encapsulants, printed circuit boards, resin sheets, and build-up laminates, as well as lightweight, high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, and in 3D printing applications. [Background technology]

[0002] Epoxy resins are widely used in fields such as electrical and electronic applications (cast products, laminates, IC encapsulation materials, etc.), structural materials, adhesives, and paints due to their excellent electrical, mechanical, adhesive, and thermal properties.

[0003] In recent years, in the electrical and electronic fields, there has been a demand for further improvements in various properties of resin compositions, such as flame retardancy, moisture resistance, adhesion, dielectric properties, high purity, low viscosity for high-density filling of fillers (inorganic or organic fillers), and improved reactivity to shorten molding cycles (Patent Document 1). Furthermore, for structural materials, there is a demand for lightweight materials with excellent mechanical properties in applications such as aerospace materials and leisure and sports equipment. Particularly in the semiconductor encapsulation field and substrates (the substrate itself or its surrounding materials), the evolution of semiconductors has led to increased complexity through thinning, stacking, systemization, and three-dimensionalization, requiring extremely high levels of heat resistance, low water absorption, and low dielectric loss tangent.

[0004] Against this backdrop, polymer materials with excellent low dielectric properties are being investigated. For example, Patent Document 1 proposes a composition containing an active ester as a curing agent for epoxy resins. However, in the field of thermosetting packaging materials for cutting-edge semiconductor devices such as AI chips, dielectric properties at a level unattainable with conventional active ester resins are required. Furthermore, properties that are highly inversely related to dielectric properties, such as fluidity, solvent solubility, and compatibility with other resin components, are also required.

[0005] On the other hand, polyester resins using phthalimide skeleton-containing bisphenol compounds have been known for a long time (Non-Patent Document 1). However, the polyester resin described in that document was designed as a thermoplastic resin, and has a very high molecular weight, poor fluidity, solvent solubility, and compatibility with other resin components, making it unsuitable for thermosetting mounting materials. Furthermore, Patent Document 2 proposes a technology for using the polyester resin as a curing agent for epoxy resins, but the specification states that "the glass transition temperature is 200°C or higher," which clearly indicates that its molecular weight also exceeds the range that can be used for thermosetting mounting materials for state-of-the-art devices. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Journal of Polymer Science, 2(A), pp437-459(1964) [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2009-235165 [Patent Document 2] Patent No. 6676529 [Patent Document 3] Patent No. 7056196 [Overview of the project] [Problems that the invention aims to solve]

[0008] As described above, the active ester resin designed for known epoxy resin curing agent applications cannot satisfy the high dielectric properties required in the state-of-the-art semiconductor field. Further, almost all of the polyester resins using known phthalimide skeleton-containing bisphenol compounds are designed for thermoplastic resin applications, and even the technology proposed as a curing agent for epoxy resins described in Patent Document 2 has poor solubility and fluidity and cannot be applied to the state-of-the-art semiconductor field. Furthermore, it does not have the high heat resistance and low thermal expansion properties that can realize a chiplet system or a 3D mounting system that requires high warp suppression.

[0009] Patent Document 3 discloses a compound having a naphthyl group at the terminal. However, the compound having a naphthyl group has high crystallinity, and when the applicant of the present application synthesized the compound described in Patent Document 3 and stored it in a dissolved state in a solvent such as toluene or MEK, crystals were precipitated. Further, in order to solve this crystal precipitation problem, when the molecular weight is reduced to lower the softening point, a problem occurs in that the heat resistance is lowered.

[0010] As a result of intensive studies on means for solving such problems, the inventors have found that an active ester resin having a specific molecular structure can highly satisfy this problem, and thus have completed the present invention. Specifically, it has been found that those having a specific molecular structure and molecular weight distribution unexpectedly have a low softening point and further excellent heat resistance and dielectric properties.

Means for Solving the Problems

[0011] That is, the present invention relates to the following [1] to

[18] . In the present invention, “(numerical value 1) to (numerical value 2)” indicates that the upper and lower limit values are included. [1] An active ester resin (A) represented by the following formula (1).

[0012]

Chemical formula

[0013] (In formula (1), X A each independently represents a monovalent organic group represented by the following formula (2), and X B each independently represents a divalent organic group containing at least one aromatic ring, and X C each independently represents a divalent organic group represented by the following formula (3). n is the average value of the number of repetitions, and 0 < n ≤ 10.)

[0014] [Chemical formula]

[0015] (In formula (2), when there are plural R's, they exist independently and each represents a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, or an alkoxy group having 1 to 10 carbon atoms. r represents an integer of 0 to 4. * represents a bond.)

[0016] [Chemical formula]

[0017] (In formula (3), when there are plural R's, they exist independently and each 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 of 0 to 4. * represents a bond.) [2] The active ester resin (A) according to the preceding [1], wherein in the above formula (3), m is 0. [3] The active ester resin according to the preceding [1], wherein in the above formula (1), the content of the n = 1 species determined by differential refractive index detector detection in gel permeation chromatography (GPC) is 10 area% or more and 80 area% or less. [4] An active ester resin (A) obtained by polycondensation reaction of a substituted or unsubstituted biphenyl compound (a) having one aromatic hydroxyl group, a compound (b) having two aromatic hydroxyl groups, and an aromatic compound and / or its acid halide having two carboxyl groups, Compound (b) contains bisphenols (f) having the chemical structure represented by the following formula (4): An active ester resin (A) in which the proportion of molecules containing bisphenols (f), as determined by differential refractometer detection in gel permeation chromatography, is 10 to 95 area percent of the total amount of the active ester resin (A).

[0018] [ka]

[0019] (In formula (4), 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.) [5] An active ester resin according to any one of the preceding paragraphs [1] to [4], wherein the weight-average molecular weight is 500 to 8000. [6] An active ester resin (A) according to any one of the preceding paragraphs [1] to [5], wherein the softening point measured by the Mettler softening point method is 40 to 150°C. [7] A resin varnish containing 30% by mass or more of the active ester resin (A) described in any one of the preceding paragraphs [1] to [6], A resin varnish in which the content of organic solvent species with a boiling point of 150°C or lower is 50% by mass or more of the total amount of organic solvents in the resin varnish. [8] A curable resin composition (C) comprising an active ester resin (A) as described in any one of the preceding paragraphs [1] to [6]. [9] Furthermore, the curable resin composition (C) described in paragraph [8] contains at least one selected from a curing accelerator, polymerization initiator, epoxy resin, active ester resin other than active ester resin (A), phenol resin, polyphenylene ether compound, amine resin, compound having an ethylenically unsaturated bond, isocyanate resin, polyamide resin, maleimide compound, cyanate ester resin, polyimide resin, polybutadiene and modified thereof, polystyrene and modified thereof, polyethylene and modified thereof, and benzoxazine compound.

[10] The curable resin composition (C) according to the preceding paragraph [9], wherein the epoxy resin contains 20% by mass or more of epoxy resin with an epoxy equivalent of 250 g / eq. or more.

[11] Furthermore, the thermosetting resin composition (C) according to any one of the preceding paragraphs [8] to

[10] , wherein it contains an inorganic filler (D), and the content of the inorganic filler (D) in the total amount of the curable resin composition is 40% by mass or more.

[12] Furthermore, a curable resin composition (C) according to any one of the preceding paragraphs [8] to

[11] , which contains glass fibers (E).

[13] A cured product obtained by curing a curable resin composition (C) described in any one of the preceding paragraphs [8] to

[12] .

[14] A semiconductor encapsulating material (F) obtained by processing a curable resin composition (C) described in any one of the preceding paragraphs [8] to

[12] .

[15] A copper-clad laminate (G) obtained by processing a curable resin composition (C) described in any one of the preceding paragraphs [8] to

[12] .

[16] An interlayer insulating material (H) for build-up substrates obtained by processing a curable resin composition (C) described in any one of the preceding paragraphs [8] to

[12] .

[17] A semiconductor device obtained by processing at least one material selected from the semiconductor encapsulating material (F) described in the preceding paragraph

[14] , the copper-clad laminate (G) described in the preceding paragraph

[15] , and the interlayer insulating material (H) for build-up substrates described in the preceding paragraph

[16] .

[18] A semiconductor package obtained by processing at least one material selected from the semiconductor encapsulation material (F) described in the preceding paragraph

[14] , the copper-clad laminate (G) described in the preceding paragraph

[15] , and the interlayer insulating material (H) for build-up substrates described in the preceding paragraph

[16] . [Effects of the Invention]

[0020] According to the present invention, it is possible to provide an active ester resin, a curable resin composition, and a cured product thereof that have a low softening point, excellent low dielectric properties, and heat resistance. [Brief explanation of the drawing]

[0021] [Figure 1] The GPC chart for Example 1 is shown. [Figure 2] The GPC chart for Comparative Example 1 is shown. [Figure 3] The GPC chart for Comparative Example 2 is shown. [Modes for carrying out the invention]

[0022] The embodiments of the present invention (hereinafter also referred to as "this embodiment") will be described in more detail below.

[0023] The active ester resin of this embodiment is represented by the following formula (1).

[0024] [ka]

[0025] In the above equation (1), X A Each of these independently represents a monovalent organic group represented by the following formula (2), and X B Each independently represents a divalent organic group containing at least one aromatic ring, X CEach independently represents a divalent organic group represented by the following formula (3). n is the average value of the number of repetitions, where 0 < n ≤ 10, preferably 0.1 ≤ n ≤ 8, more preferably 0.3 ≤ n ≤ 6, and particularly preferably 0.5 ≤ n ≤ 5. The value of n can be inferred from the charging ratio of the raw materials or calculated from the value of the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) measurement. The gel permeation chromatography (GPC) measurement in this embodiment is performed by the method described in the examples below.

[0026]

Chemical formula

[0027] In the above formula (2), a plurality of R's exist independently and each represents a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, or an alkoxy group having 1 to 10 carbon atoms, preferably a hydrocarbon group having 1 to 8 carbon atoms, more preferably a hydrocarbon group having 1 to 5 carbon atoms. r represents an integer from 0 to 4, preferably 0. * represents a bond.

[0028]

Chemical formula

[0029] In the above formula (3), a plurality of R's exist independently and each represents a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom, preferably a hydrocarbon group having 1 to 8 carbon atoms, more preferably a hydrocarbon group having 1 to 5 carbon atoms. m represents an integer from 0 to 4, preferably 0. * represents a bond.

[0030] 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. Being within the above range provides excellent solvent solubility, compatibility, heat resistance, and dielectric properties.

[0031] In the above formula (1), the content of the n = 1 component determined by differential refractive index detection in gel permeation chromatography (GPC) is preferably 10 area% or more and 80 area% or less, more preferably 15 area% or more and 60 area% or less, and particularly preferably 15 area% or more and 40 area% or less. By being within the above range, it is excellent in solvent solubility, compatibility, low thermal expansion property, heat resistance, and dielectric properties.

[0032] The number average molecular weight of the active ester resin of the present embodiment can be determined by differential refractive index detection in gel permeation chromatography (GPC), and is preferably 300 or more and 5000 or less, more preferably 400 or more and 4000 or less, and particularly preferably 500 or more and 3000 or less. The weight average molecular weight determined by differential refractive index detection in gel permeation chromatography (GPC) is preferably 500 or more and 8000 or less, more preferably 600 or more and 6000 or less, and particularly preferably 800 or more and 5000 or less. When the number average molecular weight and the weight average molecular weight are below the above upper limit values, it is excellent in solvent solubility, compatibility, fluidity, curability, low thermal expansion property, and dielectric properties, and when they are above the lower limit values, the cured product is excellent in heat resistance.

[0033] [Organic group X A X in the above formula (1) A will be described in detail. X A has a terminal blocking function necessary to achieve optimization of a specific molecular weight distribution range and viscosity, and further affects the softening point and fluidity of the active ester resin, the dielectric properties, heat resistance, thermal expansion property, elastic modulus, and mechanical properties of the cured product depending on the structure.

[0034] In formula (1), X A each independently has a structure represented by the above formula (2). By having the structure of the above formula (2), it is excellent in low dielectric properties due to the effect of reducing the softening point of the resin caused by stacking inhibition derived from the steric hindrance of the phenyl group and the reduction of polar groups.

[0035] X A It is preferable to use a substituted or unsubstituted biphenyl compound (a) as a raw material, which can be represented by the following formula (2A).

[0036] [ka]

[0037] In the above formula (2A), 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, preferably a hydrocarbon group having 1 to 8 carbon atoms, and more preferably a hydrocarbon group having 1 to 5 carbon atoms. r represents an integer from 0 to 4, preferably 0.

[0038] X A It may contain other monovalent organic groups. 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.

[0039] [Organic group X B ] X in equation (1) above B This will be explained in detail. In equation (1) above, XB Each of these independently represents a divalent organic group containing at least one aromatic ring. B The aromatic ring contained may be either a monocyclic aromatic ring or a fused polycyclic aromatic ring formed by the fusion of two or more monocyclic aromatic rings. Furthermore, the aromatic ring may be either an aromatic carbocyclic ring or an aromatic heterocyclic ring.

[0040] From the viewpoint of significantly obtaining the desired effects of the present invention, X B The aromatic ring contained is preferably an aromatic carbon ring. The number of carbon atoms in the aromatic carbon ring is preferably 6 to 14, more preferably 6 to 12. Therefore, in a preferred embodiment, X B The aromatic rings contained in it are aromatic carbocyclic rings with 6 to 14 carbon atoms.

[0041] X B The aromatic ring contained in may have substituents. The substituent is 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. Among these, one or more selected from hydrocarbon groups having 1 to 10 carbon atoms and alkoxy groups having 1 to 10 carbon atoms is 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, unsaturated aliphatic hydrocarbon groups having 2 to 6 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms is even more preferred, and aryl groups having 6 to 10 carbon atoms are particularly preferred. Also, X A If the aromatic ring contained in 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 an allyl group being more preferred.

[0042] X BIt is preferable to use 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.

[0043] 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, 1,3,5-benzenetricarboxylic acid, and their acid halide compounds.

[0044] [Organic group X C ] X C This is the core skeleton of the active ester resin and has the structure represented by formula (4) above in the present invention. In substrates for high-speed transmission, a dielectric loss tangent (Df) of 0.005 or less is required to reduce transmission loss, and having the structure of formula (4) above results in excellent low dielectric properties, heat resistance, and elastic modulus due to the molecular motion suppression effect derived from the rigid skeleton and the reduction of polar groups due to being a divalent organic group.

[0045] X C It may contain other divalent organic groups. Specifically, examples include bisphenol A, bisphenol F, bisphenol S, bisphenol M, bisphenol AD, biphenol, dihydroxynaphthalene, fluorenebisphenol, terpene diphenol, 4,4'-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, 3,3',5,5'-tetramethyl-(1,1'-biphenyl)-4,4'-diol, hydroquinone, resorcinol, naphthalenediol, tris-(4-hydroxyphenyl)methane, and 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane.

[0046] The active ester equivalent of the active ester resin in this embodiment is preferably 150 g / eq. or more and 2000 g / eq. or less, more preferably 160 g / eq. or more and 1000 g / eq. or less, and particularly preferably 180 g / eq. or more and 500 g / eq. or less. The active ester equivalent represents the mass of the resin containing one equivalent of active ester groups. If the active ester equivalent is less than 150 g / eq., the heat resistance may deteriorate. If the active ester equivalent exceeds 2000 g / eq., the curability may decrease. The active ester equivalent can be estimated from the raw material mixing ratio or calculated from the number-average molecular weight (Mn) value obtained by gel permeation chromatography (GPC).

[0047] The softening point of the activated ester resin in this embodiment is preferably 40 to 150°C, more preferably 60 to 150°C, and even more preferably 80 to 140°C. If the softening point is higher than 150°C, the solvent may be removed before the resin softens when the solvent is distilled off, potentially leading to a large amount of residual solvent and increased load on the stirrer. Furthermore, 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.

[0048] [Method for producing activated ester resin] The method for producing the active ester resin of this embodiment is not particularly limited, but it can be obtained by polycondensation reaction of a substituted or unsubstituted biphenyl compound (a) having one aromatic hydroxyl group, a compound (b) having two aromatic hydroxyl groups, and an aromatic compound and / or its acid halide having two carboxyl groups (c).

[0049] 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 resulting active ester resin (for example, the number of repeats n in formula (1) above) can be adjusted.

[0050] (b) Component contains bisphenols (f) having the chemical structure represented by the following formula (4). Component (f) is preferably present in 20 to 100% by mass of component (b), and more preferably in 40 to 100% by mass.

[0051] [ka]

[0052] In equation (4) above, R and m have the same meaning as in equation (3) above.

[0053] In this embodiment, the proportion of molecules containing component (f), as determined by differential refractometer detection in gel permeation chromatography, is preferably 10 to 95 area%, more preferably 40 to 95 area%, and particularly preferably 60 to 90 area% in the total amount of active ester resin. When only component (f) is used as component (b), the molecules that do not contain component (f) are the reaction products of only components (a) and (c). When a substance other than component (f), (f-1), is used in combination as component (b), the molecules that do not contain component (f) include not only the reaction products of only components (a) and (c), but also the reaction products of components (a), (f-1), and (c).

[0054] 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, and dimethyl sulfone and dimethyl sulfoxide 1,3-dimethyl-2-2-imidazolidinone, but are not limited to these, and two or more solvents may be used in combination.

[0055] 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.

[0056] 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.

[0057] 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 the upper limit, hydrolysis of the compound in this embodiment may proceed, potentially generating by-products. Below the lower limit, the reaction may not proceed sufficiently.

[0058] 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.

[0059] [Curable resin composition] The curable resin composition of this embodiment can be used by mixing various materials in addition to the active ester resin of this embodiment. Examples of materials that can be mixed include epoxy resins, amine compounds, amide compounds, acid anhydride compounds, phenolic resins, active ester resins other than the active ester resin of this embodiment, carboxylic acid compounds, maleimide compounds, cyanate compounds, isocyanate compounds, polyphenylene ether compounds, compounds having ethylenically unsaturated bonds, polyamide compounds, polyimide compounds, allyl compounds, polybutadiene and modified thereof, polystyrene and modified thereof, polyethylene and modified thereof, benzoxazine compounds, etc. These may be used individually or in combination of multiple types. Among these compounds, it is preferable to include epoxy resins, phenolic resins, and active ester resins in order to balance heat resistance, adhesion, dielectric properties, and mechanical properties. By including these compounds, the brittleness of the cured product can be improved and adhesion to metals can be enhanced, and cracks in the package can be suppressed during reliability tests such as solder reflow and thermal cycling. 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 added while taking advantage of the low dielectric properties of the active ester resin of this embodiment. Examples of these components can be used as shown below.

[0060] [Epoxy resin] The following are examples of preferred epoxy resins, but are not limited to these. The epoxy resin may be liquid or solid, and may be used individually or in combination of multiple types.

[0061] Examples of liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin (4,4'-(1,3-phenylenediisopridiene)bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(1,4-phenylenediisopridiene)bisphenol type epoxy resin), bisphenol Z type epoxy resin (4,4'-cyclohexydienebisphenol 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, oxazolidone ring skeleton-containing epoxy resin, and epoxy resin having a butadiene structure.Specific examples include "RE310S", "RE410S" (both manufactured by Nippon Kayaku Co., Ltd., bisphenol A type epoxy resin), "RE303S", "RE304S", "RE403S", "RE404S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy resin), "HP4032", "HP4032D", "HP4032SS" (all manufactured by DIC Corporation, naphthalene type epoxy resin), "828US", "jER828EL", "825", "828EL" (all manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin), "jE807", "1750" (both manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin), "jER152" (manufactured by Mitsubishi Chemical Corporation, phenol novolac type epoxy resin), "jER604", "jER630", "630LSD" (and others). Examples include: (above, manufactured by Mitsubishi Chemical Corporation, glycidylamine type epoxy resin), "GAN", "GOT" (both manufactured by Nippon Kayaku Co., Ltd., glycidylamine type epoxy resin), "TSR-400" (manufactured by DIC Corporation, oxazolidone ring-containing epoxy resin), "ZX1059" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin), "EX-721" (manufactured by Nagase ChemteX Corporation, glycidyl ester type epoxy resin), "Celoxide 2021P" (manufactured by Daicel Corporation, alicyclic epoxy resin with an ester skeleton), "PB-3600" (manufactured by Daicel Corporation, epoxy resin with a butadiene structure), "ZX1658", "ZX1658GS" (both manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., liquid 1,4-glycidylcyclohexane type epoxy resin). These may be used individually or in combination of two or more types.

[0062] Examples of solid epoxy resins include bixylenol-type epoxy resin, naphthol-type epoxy resin, naphthol-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, tetraphenylethane-type epoxy resin, imide-skeleton-type epoxy resin, isocyanur-type epoxy resin, and the like. Specific examples include "HP4032H", "HP-4770" (manufactured by DIC Corporation, naphthalene-type epoxy resin), "HP-4750" (manufactured by DIC Corporation, naphthalene-type trifunctional epoxy resin), "HP-4700", "HP-4710" (both manufactured by DIC Corporation, naphthalene-type tetrafunctional epoxy resin), "N-690" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), and "N-695" (manufactured by DIC Corporation, cresol novolac). (Type epoxy resin), "N-655-EXP-S" (manufactured by DIC Corporation, cresol novolac type epoxy resin), "HP-7200" (manufactured by DIC Corporation, dicyclopentadiene type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (all manufactured by DIC Corporation, dicyclopentadiene type epoxy resin), "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "E XA-7311-G4S, HP-6000 (both manufactured by DIC Corporation, naphthylene ether type epoxy resin), EPPN-502H, FAE-2500 (both manufactured by Nippon Kayaku Co., Ltd., trisphenol type epoxy resin), NC-7000L, NC-7300 (both manufactured by Nippon Kayaku Co., Ltd., naphthol-cresol novolac type epoxy resin), NC-3000H, NC-3000, NC-3000L "NC-3100" (all manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin), "XD-1000-2L", "XD-1000-L", "XD-1000-H" (all manufactured by Nippon Kayaku Co., Ltd., dicyclopentadiene type epoxy resin), "WHR-991S" (imide skeleton type epoxy resin), "ESN475V" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., naphthol type epoxy resin), "ESN485" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.,Naphthol novolac type epoxy resin), "YX-4000H", "YX-4000", "YL6121" (all manufactured by Mitsubishi Chemical Corporation, biphenyl type epoxy resin), "YX-4000HK" (manufactured by Mitsubishi Chemical Corporation, bixylenol type epoxy resin), "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), "YX7760" (manufactured by Mitsubishi Chemical Corporation, Examples include 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), "jER1031S" (manufactured by Mitsubishi Chemical Corporation, tetraphenylethane type epoxy resin), CNE-195LL (manufactured by Changchun Artificial Resin Co., Ltd., orthocresol novolac type epoxy resin), and "TEPIC-S" (manufactured by Nissan Chemical Corporation, isocyanurate type epoxy resin). These may be used individually or in combination of two or more types.

[0063] The epoxy resin used in the curable resin composition of this embodiment preferably contains an epoxy equivalent of 250 g / eq. or more, and its content in the total amount of epoxy resin is preferably 20% by mass or more, 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.

[0064] In the curable resin composition of this embodiment, the proportions of the active ester resin and epoxy resin are preferably such that, in order to obtain good curability and various physical properties of the cured product, the amount of carbonyloxy groups constituting the ester in the active ester resin is 0.8 to 1.5 equivalents per equivalent of epoxy groups in the epoxy resin.

[0065] [Amine compounds] Examples of the above amine compounds include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-methylenebis(2-ethyl-6-methylaniline) (MDEA), 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 2,2'-diaminodiphenylsulfone, diethyltoluenediamine, dimethylthiotoluenediamine, diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, and 3,3'-diethyltoluenediamine. Tyl-4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, 4,4'-diamino-3,3',5,5'-tetramethyldiphenylmethane, 4,4'-diamino-3,3',5,5'-tetraethyldiphenylmethane, 4,4'-diamino-3,3',5,5'-tetraisopropyldiphenylmethane, 3,3'-diisopropyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-4,4'-diaminodiphenylmethane, 3,3'-diisopropyl -5,5'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diisopropyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-5,5'-diisopropyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetra-t-butyl-4,4'-diaminodiphenylmethane 4,4'-methyl N-methylaniline, bis(aminophenyl)fluorene, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 1,3'-bis(4-aminophenoxy)benzene, 1,4'-bis(4-aminophenoxy)benzene, 1,4'-bis(4-aminophenoxy)biphenyl, 4,4'-(1,3-phenylenedisopropylidene)bisaniline, 4,4'-(1,Examples of aromatic amine compounds include, but are not limited to, 4-phenylenediisopropylidene)bisaniline, naphthalenediamine, benzidine, dimethylbenzidine, aromatic amine compounds described in Synthesis Examples 1 and 2 of International Publication No. 2017 / 170551, 1,3-bis(aminomethyl)cyclohexane, isophoronediamine, 4,4'-methylenebis(cyclohexylamine), norbornanediamine, ethylenediamine (EDA), propanediamine (PDA), tetramethylenediamine (TMDA), pentamethylenediamine (PMDA), hexamethylenediamine (HMDA), diethylenetriamine (DETA), triethylenetetramine (TETA), metaxylylenediamine (MXDA), dimer amine, and other aliphatic amines. They can be suitably used depending on the properties to be imparted to the composition. It is preferable to use aromatic amines to ensure pot life, and it is preferable to use aliphatic amines when immediate curing is desired. By using an amine-based compound containing a bifunctional component as the main component as a curing agent, a highly linear network can be constructed during the curing reaction, resulting in particularly excellent toughness.

[0066] [Amide compounds] Examples of the above-mentioned amide compounds include dicyandiamide (DICY).

[0067] [Acid anhydride compound] Examples of the above-mentioned acid anhydride compounds include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, and benzophenonetetracarboxylic acid. Specific examples include "KAYAHARD MCD" (manufactured by Nippon Kayaku Co., Ltd.), "Licacid MH-700" (manufactured by Shin Nippon Rika Co., Ltd., 4-methylhexahydrophthalic anhydride), "Licacid TH" (manufactured by Shin Nippon Rika Co., Ltd., tetrahydrophthalic anhydride), and "Licacid HH" (manufactured by Shin Nippon Rika Co., Ltd., hexahydrophthalic anhydride).

[0068] [Phenolic resin] Examples of the above-mentioned phenolic resins include polyhydric phenols (bisphenol A, bisphenol F, bisphenol S, bisphenol M, bisphenol AD, biphenol, dihydroxynaphthalene, fluorenebisphenol, terpene diphenol, 4,4'-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, 3,3',5,5'-tetramethyl-(1,1'-biphenyl)-4,4'-diol, dihydroxybenzene, naphthalenediol, tris-(4-hydroxyphenyl)methane, and 1,1,2,2-teto Lax(4-hydroxyphenyl)ethane, etc.), the aforementioned polyhydric phenols or phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes (formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, Polycondensates of cinnamaldehyde, etc., or polymers of the aforementioned polyhydric phenols or phenols with various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, disopropenylbiphenyl, butadiene, isoprene, etc.), or polycondensates of the aforementioned polyhydric phenols or phenols with ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.) Examples include polycondensates of the aforementioned polyhydric phenols or phenols with aromatic dimethanols (benzenedimethanol, biphenyldimethanol, etc.), polycondensates of the aforementioned polyhydric phenols or phenols with aromatic dichloromethyls (α,α'-dichloroxylene, bischloromethylbiphenyl, etc.), or polycondensates of the aforementioned polyhydric phenols or phenols with aromatic bisalkoxymethyls (bismethoxymethylbenzene, bismethoxymethylbiphenyl, bisphenoxymethylbiphenyl, etc.).Specific examples include "MEH-7700," "MEH-7810," "MEH-7851," and "PN" (all manufactured by Meiwa Kasei Co., Ltd., phenol novolac resins), and "GPH-65" and "GPH-103" (both manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type phenol resins).

[0069] [Activated ester resin] The above-mentioned active ester resin refers to a compound that contains at least one ester bond in its structure, and on both sides of the ester bond, an aliphatic chain, an aliphatic ring, or an aromatic ring is bonded. 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. The active ester resin may be used alone or in combination of two or more types.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] Preferred examples of active ester resins include active ester resins containing a dicyclopentadiene-type diphenol structure, active ester resins containing a naphthalene structure, active ester resins containing an acetylated phenol novolac, active ester resins containing a benzoylated phenol novolac, the compound described in Example 2 of International Publication No. 2020 / 095829, and the compound disclosed in International Publication No. 2020 / 059625. Among these, active ester resins containing a naphthalene structure and active ester resins containing a dicyclopentadiene-type diphenol structure are more preferred. The dicyclopentadiene-type diphenol structure represents a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

[0074] Commercially available activated ester resins include, for example, "EXB9451," "EXB9460," "EXB9460S," "HPC-8000-65T," "HPC-8000H-65TM," "EXB-8000L-65TM," and "EXB-8150-65T" (manufactured by DIC Corporation), which are activated ester resins containing a dicyclopentadiene-type diphenol structure, and "EXB9416-70BK" (manufactured by DIC Corporation), which is an activated ester resin containing a naphthalene structure. Examples of active ester resins containing acetylated phenol novolacs include "DC808" (manufactured by Mitsubishi Chemical Corporation), active ester resins containing benzoylated phenol novolacs include "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation), "EXB-9050L-62M" (manufactured by DIC Corporation) as a phosphorus atom-containing active ester curing agent, and "Unifiner W-575" as an active ester resin containing a bisphenol A structure.

[0075] [Carboxylic acid compounds] Examples of the carboxylic acid compounds mentioned above include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, oxalic acid, malonic acid, succicic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanediic acid, dodecanediic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic 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, and 4,4'-dicarboxydiphenyl sulfide. A commercially available product is G4-142MHR (manufactured by Nippon Kayaku Co., Ltd.).

[0076] [Maleimide compounds] Examples of the above maleimide compounds include phenylmaleimide, 4,4'-diphenylmethanebismaleimide, polyphenylmethanemaleimide, m-phenylenebismaleimide, 2,2'-bis[4-(4-maleimidophenoxy)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-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, and Zyloc-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, polymaleimide derived from aromatic vinyl compounds and anilines described in Japanese Patent Publication No. 2023-007239, 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 Examples include maleimide compounds described in "~Continued Story of Epoxy Resin CAS Numbers~ Memo on CAS Numbers of Hardeners, Part 32: Bismaleimide (2)". Commercially available examples include MIR-3000-70MT (biphenyl aralkyl type maleimide compound, manufactured by Nippon Kayaku Co., Ltd.) and MIZ-001 (manufactured by Nippon Kayaku Co., Ltd.).

[0077] [Cyanate compounds] Cyanate compounds are obtained by reacting phenol compounds with cyanide halides. Specific examples include 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 compounds obtained by converting the hydroxyl groups of phenol-dicyclopentadiene cocondensates to cyanate groups. A commercially available example is SYTESTER TA (manufactured by Mitsubishi Gas Chemical Company, a bisphenol A type cyanate resin). These can be used individually or in combination. Furthermore, the cyanate compound whose synthesis method is described in Japanese Patent Publication No. 2005-264154 is particularly preferred as a cyanate compound because it has excellent low hygroscopicity, flame retardancy, and dielectric properties. The cyanate compound may also contain catalysts such as zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octoate, tin octoate, lead acetylacetonate, or dibutyltin maleate to trimerize the cyanate group as needed and form a sym-triazine ring.

[0078] 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 compound and the curable resin composition.

[0079] [Isocyanate compounds] An isocyanate compound is a compound that has two or more isocyanate groups in its molecule. Examples of isocyanate compounds include, but are not limited to, aromatic diisocyanates such as p-phenylenediisocyanate, m-phenylenediisocyanate, p-xylenediisocyanate, m-xylenediisocyanate, 2,4-tolylenediisocyanate, 2,6-tolylenediisocyanate, 4,4'-diphenylmethanediisocyanate, and naphthalenediisocyanate; aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylenediisocyanate, 4,4'-dicyclohexylmethanediisocyanate, hydrogenated xylenediisocyanate, norbornene diisocyanate, and lysine diisocyanate; biuret compounds of one or more isocyanate monomers; or isocyanate compounds obtained by trimerizing the above diisocyanate compounds; and polyisocyanates obtained by urethane reaction between the above isocyanate compounds and polyol compounds. Furthermore, these can be used individually or in combination.

[0080] [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. Commercially available products include SA-9000 (manufactured by SABIC, a polyphenylene ether compound having a methacrylic group), OPE-2St 1200, and OPE-2st 2200 (both manufactured by Mitsubishi Gas Chemical Company, polyphenylene ether compounds having a styrene structure). The number-average molecular weight (Mn) of the polyphenylene ether compound is preferably 500 to 5000, more preferably 2000 to 5000, and even more preferably 2000 to 4000. If the number-average molecular weight is less than 500, the heat resistance of the cured product tends 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] [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 acenaphthylene, indene, styrene, divinylbenzene, reaction products of the phenolic resin and halogenated compounds containing ethylenically unsaturated bonds (chloromethylstyrene, allyl chloride, methallyl chloride, acrylate chloride, methacrylate chloride, etc.), reaction products of ethylenically unsaturated phenols (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) and halogenated compounds (1,4-bis(chloromethyl)benzene, 4,4'-bis(chloromethyl)biphenyl, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuryl chloride, etc.), reaction products of epoxy resins or alcohols and (meth)acrylic acids (acrylic acid, methacrylic acid, etc.), and acid-modified products thereof. Specific examples include, but are not limited to, BVPE (bisvinylphenylethane), compounds having a vinylbenzene structure as described in WO2021 / 100658, and KAYARAD R-684. Furthermore, these can be used individually or in combination.

[0085] [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.

[0086] [Polyimide resin] Examples of polyimide resins include, but are not limited to, the reaction products of the diamine and the tetracarboxylic dianhydride exemplified below. Furthermore, these may be used individually or in combination. Specific examples include compounds having the polyimide structure described in WO2023013224A1. <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.

[0087] [Allyl compounds] Examples of the allyl compounds mentioned above include monoallyl isocyanurate, diallyl isocyanurate, and triallyl isocyanurate. Specific examples include "TAIC" (manufactured by Mitsubishi Chemical Corporation), "MA-DGIC," and "DA-MGIC" (both manufactured by Shikoku Chemicals Corporation).

[0088] [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.

[0089] [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.

[0090] [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.

[0091] [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.).

[0092] [Curing accelerator] A curing accelerator may be added to the curable resin composition of this embodiment as needed. Preferably, the curing accelerator is an anionic curing accelerator that promotes the curing reaction by generating anions upon irradiation with ultraviolet light or visible light or by heating, or a cationic curing accelerator that promotes the curing reaction by generating cations upon irradiation with ultraviolet light or visible light or by heating.Examples of usable curing accelerators include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 1,2-dimethylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, and 2-ethyl-4-methylimidazole (2E4MZ), as well as triethylamine, tributylamine, N,N-dimethyl-4-aminopyridine (DMAP), and 2,4,6-tris(dimethylaminomethyl). Tertiary amines such as phenol, 2-(dimethylaminomethyl)phenol, triethylenediamine, triethanolamine, 1,8-diazabicyclo(5,4,0)undecene-7 (DBU), 1,5-diazabicyclo[4,3,0]-nonene-5 (DBN), organophosphines such as triphenylphosphine (TPP), diphenylphosphine, tributylphosphine, triparathylphosphine, diphenylcyclohexylphosphine, tricyclohexylphosphine, trimethylphosphine, triethylphosphine Examples include organic phosphites such as tyl phosphite, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium ethyltriphenylborate, ethyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, butylphosphonium tetraphenylborate, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylphosphinetriphenylborane, tetraphenylphosphonium thiocyanate, tetraphenylphosphonium dicyanamide, butylphenylphosphonium dicyanamide, tetrabutylphosphonium decanoate, and other phosphonium salts, metal compounds such as octopz(2-ethylhexanoate) and tin octylate, tetraphenylborone salts such as 2-ethyl-4-methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate, and carboxymethyl phosphate compounds such as benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthoic acid, and salicylic acid.

[0093] In the curable resin composition of this embodiment, among the curing accelerators mentioned above, N,N-dimethyl-4-aminopyridine (DMAP) and imidazoles are preferred, particularly when used for build-up material applications or circuit board applications, due to their excellent heat resistance, dielectric properties, solder resistance, etc. When used for semiconductor encapsulation material applications, triphenylphosphine is preferred among organic phosphines, and N,N-dimethyl-4-aminopyridine (DMAP) and 1,8-diazabicyclo(5,4,0)undecene-7 (DBU) are preferred among tertiary amines, due to their excellent curability, heat resistance, electrical properties, moisture resistance reliability, etc. The curing accelerators may be used individually or in combination of two or more types.

[0094] The curing accelerator is used as needed, in an amount of 0.01 to 15 parts by weight per 100 parts by weight of epoxy resin.

[0095] [Inorganic fillers] Furthermore, inorganic fillers may be added to the curable resin composition of this embodiment as needed. Examples of inorganic fillers include, but are not limited to, powders such as crystalline silica, fused silica, synthetic silica, hollow silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, aluminum hydroxide, magnesium hydroxide, zircon, calcium silicate, calcium carbonate, magnesium carbonate, magnesium oxide, silicon carbide, silicon nitride, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, zirconium tungstate phosphate, clay, zirconia, fossilite, steatite, spinel, titania, talc, mica powder, zinc oxide, hydrotalcite, boehmite, carbon black, or beads made by shaping these into spheres. These may be used individually or in combination of two or more. The amount of these inorganic fillers used varies depending on the application, but for example, when used as a encapsulant for semiconductors, it is preferable to use them in a proportion of 20% by weight or more in the curable resin composition, more preferably 30% by weight or more, and even more preferably 70-95% by weight in order to improve the coefficient of linear expansion with the lead frame.

[0096] The curable resin composition of this embodiment may contain a release agent to improve mold release during molding. Any conventionally known release agent can be used, but examples include ester waxes such as carnauba wax and montane wax, fatty acids such as stearic acid and palmitic acid and their metal salts, and polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene. These may be used alone or in combination of two or more. The amount of these release agents added is preferably 0.5 to 3% by weight relative to the total organic components. Too little will result in poor mold release, while too much will result in poor adhesion to the lead frame and the like.

[0097] [Coupling agent] The curable resin composition of this embodiment may contain a coupling agent to enhance the adhesion between the inorganic filler and the resin component. Any conventionally known coupling agent can be used, but examples include epoxyalkoxysilanes such as vinylalkoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, various alkoxysilane compounds such as styrylalkoxysilane, methacryloxyalkoxysilane, acryloxyalkoxysilane, aminoalkoxysilanes such as N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, mercaptoalkoxysilanes such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropylmethyldimethoxysilane, isocyanatealkoxysilane, alkoxytitanium compounds, and aluminum chelates. These may be used alone or in combination of two or more. The coupling agent can be added either by first treating the surface of the inorganic filler with the coupling agent and then mixing it with the resin, or by mixing the coupling agent with the resin and then mixing in the inorganic filler.

[0098] [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.

[0099] 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.

[0100] 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.

[0101] [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.

[0102] 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 (DCP) 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, and t-amyl peroxy-2-ethylhexanoate. Examples include alkyl peresters such as noates, t-butyl peroxy-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. Specific examples include Irgacure OXE-04 and Irgacure 290 (both manufactured by BASF), but are not limited to these. Furthermore, these can 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.

[0103] 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.

[0104] 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.

[0105] [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.

[0106] The polymerization inhibitor may be added during the synthesis of the compound of this embodiment or after the synthesis. The amount of polymerization inhibitor used is 0.008 to 1 part by weight, preferably 0.01 to 0.5 parts by weight, per 100 parts by weight of the compound of this embodiment.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] Examples of the above hindered amine polymerization inhibitors include Adekastab (registered trademark) LA-40MP, Adekastab LA-40Si, Adekastab LA-402AF, Adekastab LA-87, Adekastab LA-82, Adekastab LA-81, Adekastab LA-77Y, Adekastab LA-77G, Adekastab LA-72, Adekastab LA-68, Adekastab LA-63P, Adekastab LA-57, Adekastab LA-52 (all from ADE Inc.) Examples include, but are not limited to, products such as KA, 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).

[0112] 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.

[0113] 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.

[0114] [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.

[0115] 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.

[0116] [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.

[0117] 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.

[0118] Furthermore, known additives may be added to the curable resin composition of this embodiment as needed. Specific examples of additives that can be used include polybutadiene and its modified forms, modified acrylonitrile copolymers, polystyrene, polyethylene, fluororesins, silicone gels, silicone oils, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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 weight, preferably 15 to 70% by weight, of the mixture of the curable resin composition of this embodiment and the solvent. If the composition is liquid, a cured product of the curable resin containing carbon fibers can also be obtained directly, for example, by the RTM method.

[0124] Furthermore, the curable 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.

[0125] 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 reinforcing fibers with the above varnish and then heating and drying them.

[0126] 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.

[0127] 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 using the curable resin composition of this embodiment to make a resin sheet, it is important that the film softens at the lamination temperature conditions (70°C to 140°C) in the vacuum lamination method and exhibits fluidity (resin flow) that allows for simultaneous lamination of the circuit board and resin filling of via holes or through holes present in the circuit board. It is preferable to blend the above components in such a way as to exhibit such characteristics. Furthermore, in order to prevent phenomena such as locally different characteristic values ​​caused by phase separation from occurring in the resulting resin sheet or circuit board (copper-clad laminate, etc.), uniformity of appearance is required to ensure that a certain level of performance is achieved in any desired area.

[0128] 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.

[0129] A specific method for manufacturing the above-mentioned resin sheet is to prepare a varnished resin composition by incorporating an organic solvent, apply the varnished resin composition to the surface of a support film (Y), and then dry the organic solvent by heating or blowing hot air to form a resin composition layer (X).

[0130] 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.

[0131] 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 this embodiment, the resin composition layer (X) 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.

[0132] The above-mentioned support film and protective film can be made of polyolefins such as polyethylene, polypropylene, and polyvinyl chloride, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polycarbonate, polyimide, and also release paper, copper foil, aluminum foil, and other metal foils. The support film and protective film may be treated with a mat treatment, corona treatment, or release treatment. The thickness of the support film is not particularly limited, but is 10 to 150 μm, preferably in the range of 25 to 50 μm. The thickness of the protective film is preferably 1 to 40 μm.

[0133] 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 peeling off after the resin composition layer (X) has cured, the support film (Y) is treated with a release agent beforehand.

[0134] 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 removed, and then the resin composition layer (X) is laminated to one or both sides of the circuit board so that it is in direct contact with the circuit board, for example, by a vacuum lamination method. The lamination method may be batch or continuous with a roll. If necessary, the resin sheet and circuit board may be heated (preheated) before lamination. The lamination conditions are preferably a pressure temperature (lamination temperature) of 70 to 140°C and a pressure of 1 to 11 kgf / cm². 2 (9.8 × 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.

[0135] 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).

[0136] 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 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. [Examples]

[0137] Next, the present invention will be described in more detail with reference to examples. Hereinafter, unless otherwise specified, "parts" refers to parts by mass. However, this embodiment is not limited to these examples.

[0138] 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)

[0139] [Example 1] In a flask equipped with a thermometer, condenser, and stirrer, 34.0 parts of orthophenylphenol (Tokyo Chemical Co., Ltd.), 40.6 parts of isophthalic acid chloride (Tokyo Chemical Co., Ltd.), 0.56 parts of tetrabutylammonium bromide (Kanto Chemical Co., Ltd.), and 200 parts of toluene were added and dissolved under nitrogen purging. In a separate container, 39.3 parts of N-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine were dissolved in 106.6 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 60°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 50 parts of water. After removing impurities from the obtained solution by microfiltration, toluene was removed by vacuum distillation using a rotary evaporator to obtain 94.7 parts of the active ester resin (a-1) represented by the following formula (a-1) as a solid resin (Mn: 1057, Mw: 1862). The GPC chart of the obtained compound is shown in Figure 1. The theoretical active 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 (a-1), the content of n=0 isomer was 21.4 area% as detected by differential refractometer detection in gel permeation chromatography (GPC), and the content of n=1 isomer was 27.3 area%.

[0140] [ka]

[0141] [Comparative Example 1] In a flask equipped with a thermometer, condenser, and stirrer, 28.8 parts of 1-naphthol (Tokyo Chemical Co., Ltd.), 40.6 parts of isophthalic acid chloride (Tokyo Chemical Co., Ltd.), 0.54 parts of tetrabutylammonium bromide (Kanto Chemical Co., Ltd.), and 200 parts of toluene were added and dissolved under nitrogen purging. In a separate container, 39.3 parts of N-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine were dissolved in 106.7 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 60°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 50 parts of water. After removing impurities from the obtained solution by microfiltration, toluene was removed by vacuum distillation using a rotary evaporator to obtain 78 parts of the active ester resin (b-1) represented by the following formula (b-1) as a solid resin (Mn: 943, Mw: 1759). The GPC chart of the obtained compound is shown in Figure 2. The theoretical active ester equivalent from the charging ratio of the raw materials was 235 g / eq., and the theoretical number of repeats n was 1. In the following formula (b-1), the content of n=0 isomer was 20.9 area% as detected by differential refractometer detection in gel permeation chromatography (GPC), and the content of n=1 isomer was 23.9 area%.

[0142] [ka]

[0143] [Comparative Example 2] While purging a flask equipped with a thermometer, condenser, and stirrer with nitrogen, 33.4 parts of a polycondensate of dicyclopentadiene and phenol (hydroxyl group equivalent 180 g / eq.), 28.8 parts of 1-naphthol (Tokyo Chemical Industries, Ltd.), 40.6 parts of isophthalic acid chloride (Tokyo Chemical Industries, Ltd.), and 200 parts of toluene were added and dissolved. 65.0 parts of a 25% sodium hydroxide aqueous solution were added dropwise over 2 hours while stirring the previously prepared toluene solution, maintaining the system temperature below 60°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 50 parts of water. After removing impurities from the resulting solution by microfiltration, toluene was removed by vacuum distillation using a rotary evaporator to obtain 82.1 parts of the activated ester resin (b-2) represented by the following formula (b-2) as a solid resin (Mn 712, Mw 1163). The GPC chart of the obtained compound is shown in Figure 3. The theoretical active ester equivalent from the starting material ratio was 221 g / eq., and the theoretical number of repeats n was 1.

[0144] [ka]

[0145] <Softening point measurement> Table 1 shows the results of softening point measurements for the active ester resins (a-1), (b-1), and (b-2) obtained in Experiment 1 and Comparative Examples 1 and 2. Equipment: METTLER TOLEDO FP900 Thermo System Heating rate: 2°C / min

[0146] [Table 1]

[0147] [Example 2, Comparative Examples 3 and 4] The activated ester resins (a-1), (b-1), and (b-2) obtained in Example 1 and Comparative Examples 1 and 2 were used in the amounts shown in Table 1, and vacuum-press molded while sandwiched between mirror-finish copper foil (T4X: manufactured by Fukuda Metal Copper Foil Co., Ltd.), and cured at 180°C for 2 hours. At this time, 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 carried out.

[0148] <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.

[0149] <Heat resistance test (Tg)> The glass transition temperature (the temperature at which tanδ is at its maximum value) was measured using a dynamic viscoelasticity testing machine. • Dynamic viscoelasticity measuring instrument: TA-instruments DMA-2980 • Heating rate: 2°C / min • Frequency: 10Hz

[0150] [Table 2]

[0151] The results in Tables 1 and 2 confirm that the activated ester resin of the present invention exhibits a low softening point, excellent dielectric properties, and heat resistance.

[0152] <Curing test> [Reference example 1] 5 parts of the active ester resin (a-1) obtained in Example 1, 20 parts of NC-3000 (manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin), 0.5 parts of MDEA: 4,4'-methylenebis(2-ethyl-6-methylaniline) (manufactured by Tokyo Chemical Industry Co., Ltd., amine compound), 1 part of DICY: dicyandiamide (manufactured by Tokyo Chemical Industry Co., Ltd., amide compound), 0.5 parts of KAYAHARD MCD (manufactured by Nippon Kayaku Co., Ltd., acid anhydride compound), KAYAHARD 0.5 parts of GPH-65 (manufactured by Nippon Kayaku Co., Ltd., biphenylaralkyl type phenol resin), 0.5 parts of Unifiner W-575 (manufactured by Unitika Corporation, activated ester resin), 0.5 parts of G4-142MHR (manufactured by Nippon Kayaku Co., Ltd., carboxylic acid compound), 2.5 parts of MIR-3000-70MT (manufactured by Nippon Kayaku Co., Ltd., maleimide compound), 2.5 parts of MIZ-001 (manufactured by Nippon Kayaku Co., Ltd., maleimide compound), 0.5 parts of phenylmaleimide (manufactured by Tokyo Chemical Industry Co., Ltd., maleimide compound), 0.5 parts of SYTESTER TA (manufactured by Mitsubishi Gas Chemical Company, bisphenol A type cyanate resin), 60 parts of OPE-2st 2200 (manufactured by Mitsubishi Gas Chemical Company, polyphenylene ether compound), 3 parts of a compound having an ethylenically unsaturated bond as described in WO2021 / 100658, KAYARAD 1 part R-684 (manufactured by Nippon Kayaku Co., Ltd., compound having an ethylenically unsaturated bond), 0.5 parts acenaphthylene (manufactured by Tokyo Chemical Industry Co., Ltd., compound having an ethylenically unsaturated bond), 1 part compound having a polyimide structure as described in WO2023 / 013224A1, 1 part TAIC: triallyl isocyanurate (manufactured by Mitsubishi Chemical Corporation, allyl compound), 1 part Septon 2104 (manufactured by Kuraray Co., Ltd., polystyrene modified product), 1 part benzoxazine Pd (manufactured by Shikoku Chemicals Co., Ltd., benzoxazine compound), 0.5 parts 2E4MZ: 2-ethyl-4-methylimidazole (manufactured by Shikoku Chemicals Co., Ltd., curing accelerator), 0.5 parts TPP: triphenylphosphine (manufactured by Hokko Chemical Co., Ltd., curing accelerator), 0.1 parts Octop Zn (manufactured by Hope Pharmaceutical Co., Ltd., curing accelerator), Sun-Aid 0.1 parts of SI-B5 (manufactured by Sanshin Chemical Co., Ltd., curing accelerator), 1 part of DCP: dicumyl peroxide (manufactured by Kayaku Nurion Co., Ltd., polymerization initiator), 99.2 parts of toluene as solvent, and 49 parts of tetrahydrofuran.By mixing the ingredients in a 6:1 ratio and heating them under a nitrogen atmosphere at 110°C for 10 minutes, then at 220°C for 1 hour, a cured product was obtained.

[0153] [Reference example 2] Five parts of the active ester resin (a-1) obtained in Example 1, 50 parts of NC-3000 (manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin), 10 parts of MIZ-001 (manufactured by Nippon Kayaku Co., Ltd., maleimide compound), 5 parts of the compound having an ethylenically unsaturated bond as described in WO2021 / 100658, 45 parts of KAYARAD R-684 (manufactured by Nippon Kayaku Co., Ltd., compound having an ethylenically unsaturated bond), 1 part of Irgacure OXE-04 (manufactured by BASF, polymerization initiator), and 1 part of Irgacure 290 (manufactured by BASF, polymerization initiator) were mixed and coated onto a PET film to a thickness of 100 μm. A PET film was also attached to the side not in contact with the film, and a pressure test was conducted using a high-pressure mercury lamp (365 nm) at 3000 mJ / cm². 2 By irradiating it with ultraviolet light, a cured product could be obtained. [Industrial applicability]

[0154] The active ester resin of the present invention is suitably used in electrical and electronic components such as semiconductor encapsulants, printed circuit boards, and build-up laminates.

Claims

1. An activated ester resin (A) represented by the following formula (1). 【Chemistry 1】 (In formula (1), X Ａ Each of these independently represents a monovalent organic group represented by the following formula (2), and X Ｂ Each independently represents a divalent organic group containing at least one aromatic ring, X Ｃ Each of these independently represents a divalent organic group represented by the following formula (3). n is the average number of repeats, where 0 < n ≤ 10. 【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. r represents an integer from 0 to 4. * represents a bond.) 【Transformation 3】 (In formula (3), 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 a bond.)

2. The activated ester resin (A) according to claim 1, wherein m is 0 in formula (4) above.

3. The active ester resin according to claim 1, wherein the content of n=1, as determined by differential refractive index detection in gel permeation chromatography (GPC), is 10 area percent or more and 80 area percent or less.

4. An active ester resin (A) obtained by polycondensation reaction of a substituted or unsubstituted biphenyl compound (a) having one aromatic hydroxyl group, a compound (b) having two aromatic hydroxyl groups, and an aromatic compound and / or its acid halide (c) having two carboxyl groups, Compound (b) contains a bisphenol (f) having the chemical structure represented by the following formula (2): An active ester resin (A) in which the proportion of molecules containing bisphenols (f), as determined by differential refractometer detection in gel permeation chromatography, is 10 to 95 area percent of the total amount of the active ester resin (A). 【Chemistry 4】 (In formula (4), 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.)

5. The activated ester resin according to any one of claims 1 to 4, wherein the weight-average molecular weight is 500 to 8000.

6. The activated ester resin (A) according to any one of claims 1 to 4, wherein the softening point measured by the Mettler softening point method is 40 to 150°C.

7. A resin varnish containing 30% by mass or more of the active ester resin (A) described in any one of claims 1 to 4, A resin varnish in which the content of organic solvent species with a boiling point of 150°C or lower is 50% by mass or more of the total amount of organic solvents in the resin varnish.

8. A curable resin composition (C) comprising the active ester resin (A) according to any one of claims 1 to 4.

9. Furthermore, the curable resin composition (C) according to claim 8 contains at least one selected from a curing accelerator, polymerization initiator, epoxy resin, active ester resin other than active ester resin (A), phenol resin, polyphenylene ether compound, amine resin, compound having an ethylenically unsaturated bond, isocyanate resin, polyamide resin, maleimide compound, cyanate ester resin, polyimide resin, polybutadiene and modified thereof, polystyrene and modified thereof, polyethylene and modified thereof, and benzoxazine compound.

10. The curable resin composition (C) according to claim 9, wherein the epoxy resin contains 20% by mass or more of epoxy resin with an epoxy equivalent of 250 g / eq. or more.

11. Furthermore, the thermosetting resin composition (C) according to claim 8 contains an inorganic filler (D), wherein the content of the inorganic filler (D) in the total amount of the curable resin composition is 40% by mass or more.

12. Furthermore, the curable resin composition (C) according to claim 8 contains glass fibers (E).

13. A cured product obtained by curing the curable resin composition (C) described in claim 8.

14. A semiconductor encapsulating material (F) obtained by processing the curable resin composition (C) according to claim 8.

15. A copper-clad laminate (G) obtained by processing the curable resin composition (C) described in claim 8.

16. An interlayer insulating material (H) for a build-up substrate obtained by processing the curable resin composition (C) described in claim 8.

17. A semiconductor device obtained by processing at least one material selected from the semiconductor encapsulating material (F) described in claim 14, the copper-clad laminate (G) described in claim 15, and the interlayer insulating material (H) for build-up substrates described in claim 16.

18. A semiconductor package obtained by processing at least one material selected from the semiconductor encapsulating material (F) described in claim 14, the copper-clad laminate (G) described in claim 15, and the interlayer insulating material (H) for build-up substrates described in claim 16.

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