Curable resin composition and its cured product

Abstract

To provide: a curable resin composition that has a high biomass degree and is excellent in high thermostability, low dielectric properties, and mechanical characteristics; and a cured matter of the curable resin composition.SOLUTION: A curable resin composition includes an epoxy resin represented by the following formula (1), and a lignin modified phenol resin or a cashew modified phenol resin. (In formula (1), n is an average value of repeating numbers and indicates a real number of 1<n<15.)SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a curable resin composition containing a specific epoxy resin and a lignin-modified phenolic resin or a cashew-modified phenolic resin, and a cured product thereof, and is suitably used in the fields of semiconductor device encapsulating materials, printed wiring boards, build-up laminated boards and other electrical and electronic components, lightweight and high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, 3D printing applications, and adhesives.

Background Art

[0002] Epoxy resins are widely used in the fields of electrical and electronic components, structural materials, adhesives, paints, etc. due to their workability and the excellent electrical properties, heat resistance, adhesiveness, moisture resistance (water resistance), etc. of their cured products. In recent years, particularly in the electrical and electronic fields, with the development, further improvement of various resin properties such as heat resistance, low dielectric constant, and low dielectric tangent has been demanded. Also, as structural materials, materials that are lightweight and have excellent mechanical properties are demanded in aerospace materials, leisure and sports equipment applications, etc.

[0003] In recent years, biomass resources have attracted attention as carbon-neutral resources from the perspective of environmental issues. Furfural is known as a compound derived from biomass, and Patent Document 1 discloses an epoxy resin using furfural as a raw material.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since Patent Document 1 uses full furfural as a raw material, mixes it with an epoxy resin and a phenol novolak resin which is a curing agent derived from petrochemicals to form an epoxy resin composition, the biomass content of the composition is low.

[0006] Generally, when trying to increase the biomass content, it becomes difficult to maintain the performance required for the curable resin composition. Therefore, a curable resin composition that satisfies the required characteristics while having a high biomass content has been demanded.

[0007] The present invention has been made in view of the above situation, and an object thereof is to provide a curable resin composition having a high biomass content and excellent high heat resistance, low dielectric properties, and mechanical properties, and a cured product thereof.

Means for Solving the Problems

[0008] That is, the present invention relates to the following [1] to [9]. In the present invention, “(numerical value 1) to (numerical value 2)” indicates that the upper and lower limit values are included. [1] A curable resin composition containing an epoxy resin represented by the following formula (1) and a lignin-modified phenol resin or a cashew-modified phenol resin.

[0009]

Chemical formula

[0010] (In formula (1), n is the average value of the number of repetitions, and represents a real number of 1 < n < 15.) [2] The curable resin composition according to the above item [1], wherein the biomass content of the lignin-modified phenol resin or the cashew-modified phenol resin is 20% or more. [3] The curable resin composition according to the above item [1] or [2], wherein the ICI viscosity (150 ° C) of the epoxy resin is 0.01 to 0.20 Pa·s. [4] The curable resin composition according to any one of [1] to [3] above, having a biomass content of 20% or more. [5] The curable resin composition according to any one of [1] to [4] above, which is for carbon fiber reinforced plastics. [6] The curable resin composition according to any one of [1] to [4] above, which is for semiconductor element encapsulation materials. [7] The curable resin composition according to any one of [1] to [4] above, which is for printed wiring boards. [8] A cured product obtained by curing the curable resin composition according to any one of [1] to [7] above. [Effects of the Invention]

[0011] The present invention relates to a curable resin composition having a high biomass content and excellent high heat resistance, low dielectric properties, and mechanical properties. Therefore, the present invention is useful for insulating materials for electric and electronic components (such as high reliability semiconductor encapsulation materials), laminates (such as printed wiring boards, build-up substrates, etc.), various composite materials including CFRP, adhesives, and the like. [Brief Description of the Drawings]

[0012] [Figure 1] Shows the GPC chart of Synthesis Example 1. [Figure 2] Shows the GPC chart of the lignin-modified phenolic resin used in Example 1. [Modes for Carrying Out the Invention]

[0013] The curable resin composition of the present embodiment contains an epoxy resin represented by the following formula (1) and a lignin-modified phenolic resin or a cashew-modified phenolic resin. 4]

[0014] [Chemical Formula]

[0015] (In formula (1), n is the average value of the number of repetitions and represents a real number where 1 < n < 15.)

[0016] In the above formula (1), the value of n can be determined from the number average molecular weight obtained by measuring the epoxy resin by gel permeation chromatography (GPC, detector: RI), or from the area ratio of each separated peak. It is preferable that n is a real number where 1 < n < 15, more preferably 1 < n < 10, and particularly preferably 1 < n < 5.)

[0017] The epoxy resin represented by the above formula (1) can be obtained by reacting a phenol resin represented by the following formula (2) with epihalohydrin.)

[0018] [Chemical formula]

[0019] (In formula (2), n is the average value of the number of repetitions and represents a real number where 1 < n < 15.)

[0020] The preferable range of n in the above formula (2) is the same as that of the above formula (1).

[0021] The epihalohydrin can be easily obtained from the market. The amount of epihalohydrin used is preferably 2.0 to 10 moles, more preferably 3.0 to 8.0 moles, and even more preferably 3.5 to 6.0 moles per 1 mole of the hydroxyl group of the raw material phenol mixture.)

[0022] In the above reaction, an alkali metal hydroxide can be used as a catalyst to promote the epoxidation step. Examples of the alkali metal hydroxide that can be used include sodium hydroxide, potassium hydroxide, etc. A solid may be used, or an aqueous solution thereof may be used. In this embodiment, in particular, from the viewpoints of solubility and handling, it is preferable to use a solid molded into flakes.) The amount of alkali metal hydroxide used is preferably 0.90 to 1.5 moles, more preferably 0.95 to 1.25 moles, and even more preferably 0.99 to 1.15 moles, per mole of hydroxyl groups in the raw material phenol mixture.

[0023] Furthermore, quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, and trimethylbenzylammonium chloride may be added as catalysts to accelerate the reaction. The amount of quaternary ammonium salt used is preferably 0.1 to 15 g, and more preferably 0.2 to 10 g, per mole of hydroxyl groups in the raw material phenol mixture.

[0024] The reaction temperature is preferably 30 to 90°C, and more preferably 35 to 80°C. In this embodiment in particular, a temperature of 50°C or higher is preferred for higher purity epoxidation, and especially preferably 60°C or higher. The reaction time is preferably 0.5 to 10 hours, more preferably 1 to 8 hours, and especially preferably 1 to 3 hours. A reaction time that is too short is undesirable because the reaction will not proceed completely, and a reaction time that is too long is undesirable because byproducts will form. After washing the reactants from these epoxidation reactions with water, or without washing, the epihalohydrins and solvents are removed by heating under reduced pressure. Furthermore, to obtain an epoxy resin with fewer hydrolyzable halogens, the recovered epoxy resin can be dissolved in a ketone compound having 4 to 7 carbon atoms (for example, methyl isobutyl ketone, methyl ethyl ketone, cyclopentanone, cyclohexanone, etc.) as a solvent, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to carry out the reaction and ensure ring closure. In this case, the amount of alkali metal hydroxide used is preferably 0.01 to 0.3 moles, more preferably 0.05 to 0.2 moles, per mole of hydroxyl groups in the raw material phenol mixture used for epoxidation. The reaction temperature is preferably 50 to 120°C, and the reaction time is preferably 0.5 to 2 hours.

[0025] After the reaction is complete, the generated salt is removed by filtration, washing with water, etc., and the solvent is further removed by distillation under reduced pressure and heating to obtain the epoxy resin represented by formula (1).

[0026] In the synthesis method of the phenolic resin represented by formula (2) above, when a reaction (condensation) of furfural with phenols is carried out, the amount of phenols is preferably in the range of 1.5 to 20 moles, and particularly preferably 3 to 10 moles, per mole of furfural.

[0027] Examples of phenols include catechol, resorcinol, and hydroquinone as disubstituted phenols, and phenol as a monosubstituted phenol. These can be used individually or in combination of two or more types.

[0028] Examples of solvents include methanol, ethanol, propanol, isopropanol, toluene, and xylene, but are not limited to these; they may be used alone or in combination of two or more. When a solvent is used, the amount used is preferably 5 to 500 parts by weight, and more preferably 10 to 300 parts by weight, per 100 parts by weight of phenol.

[0029] In the above condensation reaction, it is preferable to use a basic catalyst. Although condensation polymerization is possible with an acidic catalyst, reactions between furfural molecules also occur, resulting in a large amount of by-products. There is also a method using organometallic compounds, but it is disadvantageous in terms of cost. Specific examples of basic catalysts include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; alkaline earth metal hydroxides such as magnesium hydroxide and calcium hydroxide; alkali metal alkoxides such as sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide, and potassium tert-butoxide; and alkaline earth metal alkoxides such as magnesium methoxide and magnesium ethoxide. However, the catalyst is not limited to these, and one or more catalysts may be used in combination. The amount of catalyst used is preferably 0.005 to 2.0 moles per mole of phenol, and more preferably 0.01 to 1.1 moles.

[0030] These condensation reactions in the presence of base catalysts are preferably carried out in the range of 40 to 180°C, particularly preferably in the range of 80 to 165°C, and the reaction time is preferably selected in the range of 0.5 to 10 hours. The reactants thus obtained are neutralized to make the system neutral, or repeatedly washed with water in the presence of a solvent, then the water is separated and drained, and the solvent and unreacted substances are removed under heating and reduced pressure to obtain the phenol resin represented by formula (2).

[0031] The curable resin composition of this embodiment contains an epoxy resin represented by formula (1) along with a lignin-modified phenol resin or a cashew-modified phenol resin. A lignin-modified phenol resin is a phenol resin modified using lignin, and one described in Japanese Patent Application Publication No. 2021-138806 is known. In addition, PLN-0051LP, a lignin-modified phenol resin, can be obtained from Aica Kogyo Co., Ltd. A cashew-modified phenol resin is a phenol resin modified using cashew oil, and one described in Japanese Patent Application Publication No. 2007-2032 is known. The amount of lignin-modified phenol resin or cashew-modified phenol resin is preferably 0.7 to 1.2 equivalents per equivalent of epoxy groups in the epoxy resin represented by formula (1). If the amount is less than 0.7 equivalents or more than 1.2 equivalents per equivalent of epoxy groups, curing may be incomplete, and good cured physical properties may not be obtained.

[0032] From an environmental perspective, the biomass content of the epoxy resin represented by formula (1) is preferably 20% or more. The biomass content of the lignin-modified phenol resin or cashew-modified phenol resin is preferably 20% or more. The biomass content of the curable resin composition of this embodiment is preferably 20% or more, and more preferably 25% or more. The upper limit of the biomass content is not particularly limited and may be 100%, but considering the balance with the cured physical properties, it is preferably 60% and more preferably 40%. A high biomass content can also reduce the amount of fossil resource-based materials such as petroleum used, and is therefore significant in terms of the sustainable use of resources.

[0033] The biomass content of each material and curable resin composition can be determined by accelerator gravimetric analysis in accordance with ASTM D6866-21.

[0034] In the curable resin composition of this embodiment, the epoxy resin represented by formula (1) can be used alone or in combination with other epoxy resins. When used in combination, the proportion of the epoxy resin represented by formula (1) in the total epoxy resin is preferably 5 to 95% by weight, more preferably 10 to 95% by weight, and even more preferably 15 to 95% by weight. If the amount added is small, sufficient heat resistance may not be achieved.

[0035] Specific examples of epoxy resins that can be used in combination with the epoxy resin represented by formula (1) above include polycondensates of bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol, bisphenol AD, etc.) or phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes (formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.); and polycondensates of the phenols and various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylben Polymers of phenols (such as divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc.); polycondensates of the phenols and ketones (such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.); polycondensates of the phenols and aromatic dimethanols (such as benzenedimethanol, biphenyldimethanol, etc.); polycondensates of the phenols and aromatic dichloromethyls (such as α,α'-dichloroxylene, bischloromethylbiphenyl, etc.); polycondensates of the phenols and aromatic bisalkoxymethyls (such as bismethoxymethylbenzene, bismethoxymethylbiphenyl, bisphenoxymethylbiphenyl, etc.); glycidyl ether epoxy resins, alicyclic epoxy resins, glycidylamine epoxy resins, glycidyl ester epoxy resins, etc. obtained by glycidly obtaining polycondensates of the bisphenols and various aldehydes or alcohols, etc. Specific examples of epoxy resins containing plant-derived components include compounds obtained by polycondensing cardanol derived from cashew oil with various aldehydes, as well as compounds obtained by epoxidizing linseed oil or soybean oil. However, these are not the only commonly used epoxy resins. These may be used individually or in combination of two or more.In particular, using it in combination with epoxy resins containing plant-derived components is preferable because it can increase the biomass content.

[0036] The curable resin composition of this embodiment may also be used in combination with curing agents other than gunin-modified phenol resin or cashew-modified phenol resin. Examples include acid anhydride compounds, amine compounds, amide compounds, phenol compounds, and active ester compounds. Specific examples of curing agents that can be used in combination include acid anhydride compounds such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride; and amide compounds such as dicyandiamide and polyamide resins synthesized from a linolenic acid dimer and ethylenediamine.o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 2,2'-diaminodiphenylsulfone, diethyltoluenediamine, dimethylthiotoluenediamine, diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenyl Lumethane, 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, 4,4'-methylenebis(N-methylaniline), bis(aminophenyl)fluorene, 3,4'-diaminodiphenyl Ether, 4,4'-diaminodiphenyl ether, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 1,3'-bis(4-aminophenoxy)benzene, 1,4'-bis(4-aminophenoxy)benzene, 1,4'-bis(4-aminophenoxy)biphenyl, 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenedi Aromatic amine compounds such as sopropylidene)bisaniline, naphthalenediamine, benzidine, and dimethylbenzidine; aliphatic amine compounds such as 1,3-bis(aminomethyl)cyclohexane, isophoronediamine, 4,4'-methylenebis(cyclohexylamine), norbornanediamine, ethylenediamine, propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, dimeramine, and triethylenetetramine;Polycondensates of bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol, bisphenol AD, etc.) or phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes (formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.), or the aforementioned phenols and various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc.) Phenolic compounds such as polymers of phenols, polycondensates of phenols and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.), polycondensates of phenols and aromatic dimethanols (benzenedimethanol, biphenyldimethanol, etc.), polycondensates of phenols and aromatic dichloromethyls (α,α'-dichloroxylene, bischloromethylbiphenyl, etc.), polycondensates of phenols and aromatic bisalkoxymethyls (bismethoxymethylbenzene, bismethoxymethylbiphenyl, bisphenoxymethylbiphenyl, etc.), polycondensates of bisphenols and various aldehydes, and modified versions thereof; active ester compounds such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds; and are not limited thereto.

[0037] The curable resin composition of this embodiment may be used in combination with a curing accelerator. Examples of curing accelerators that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, and 2-ethyl-4-methylimidazole; tertiary amines such as 2-(dimethylaminomethyl)phenol, triethylenediamine, triethanolamine, and 1,8-diazabicyclo[5,4,0]undecene-7; organophosphines such as triphenylphosphine, diphenylphosphine, and tributylphosphine; metal compounds such as tin octylate; tetraphenylphosphonium-tetraphenylborate and tetraphenylphosphonium-ethyltriphenylborate; tetraphenylboron salts such as 2-ethyl-4-methylimidazole-tetraphenylborate and N-methylmorpholine-tetraphenylborate; and carboxylic acid compounds such as benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthoic acid, and salicylic acid. 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.

[0038] The curable resin composition of this embodiment may contain inorganic fillers as needed. Examples of inorganic fillers include, but are not limited to, powders such as crystalline silica, fused silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, zirconia, fossterite, steatite, spinel, titania, and talc, or beads formed from these. These may be used individually or in combination of two or more. The amount of inorganic fillers used varies depending on the application, but for example, when used as a encapsulant for semiconductor devices, 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 especially preferable to use them in a proportion of 70 to 95% by weight to improve the coefficient of linear expansion with the lead frame.

[0039] The curable resin composition of this embodiment may contain a release agent to improve release from the mold 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 release from the mold, and too much will result in poor adhesion to the lead frame, etc.

[0040] 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 various alkoxysilane compounds such as vinylalkoxysilane, epioxyalkoxysilane, styrylalkoxysilane, methacryloxyalkoxysilane, acryloxyalkoxysilane, aminoalkoxysilane, mercaptoalkoxysilane, and isocyanatealkoxysilane, as well as alkoxytitanium compounds and aluminum chelates. These may be used alone or in combination of two or more. The coupling agent may be added by first treating the surface of the inorganic filler with the coupling agent and then kneading it with the resin, or by mixing the coupling agent with the resin and then kneading the inorganic filler.

[0041] The curable resin composition of this embodiment may contain known additives as needed. Specific examples of additives that can be used include polybutadiene and its modified forms, modified acrylonitrile copolymers, polyphenylene ether, polystyrene, polyethylene, polyimide, fluororesin, maleimide compounds, cyanate ester compounds, silicone gels, silicone oils, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

[0042] The curable resin composition of this embodiment is obtained by uniformly mixing the above components. The method for producing the curable resin composition of this embodiment is not particularly limited, but for example, it can be obtained by thoroughly mixing an epoxy resin with a curing agent, curing accelerator, inorganic filler, mold release agent, silane coupling agent, additives, etc., using an extruder, kneader, roll, planetary mixer, etc., until uniform.

[0043] The resulting curable resin composition can take various forms, such as resin sheets and prepregs, depending on the molding method. The prepreg form can be obtained, for example, by heating and melting the curable resin composition and / or resin sheet of this embodiment to reduce its viscosity and impregnating it into a fibrous substrate.

[0044] 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-like composition (hereinafter also simply referred to as 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 create a prepreg. In this case, the solvent used is in an amount that accounts 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.

[0045] Carbon fiber reinforced plastic (CFRP) can be obtained by cutting the above prepregs into the desired shape, laminating them, and then applying pressure to the laminate using methods such as press molding, autoclave molding, or sheet winding molding while heating and curing an epoxy resin composition. Furthermore, copper foil or organic film can also be laminated during the prepreg lamination process.

[0046] In addition to the methods described above, CFRP can also be molded using known methods. For example, resin transfer molding (RTM) can be used, in which a preform (a pre-molded body before resin impregnation) is prepared by cutting, laminating, and shaping a carbon fiber substrate (usually carbon fiber fabric), the preform is placed in a mold and the mold is closed, resin is injected to impregnate and harden the preform, and then the mold is opened to remove the molded product. Furthermore, various RTM methods can be used, such as the VaRTM method, the SCRIMP (Seeman's Composite Resin Infusion Molding Process) method, and the CAPRI (Controlled Atmospheric Pressure Resin Infusion) method, which more appropriately controls the resin injection process, especially the VaRTM method, by evacuating the resin supply tank described in Japanese Patent Publication No. 2005-527410 to a pressure lower than atmospheric pressure, using circulating compression, and controlling the net molding pressure. Furthermore, methods such as film stacking, which sandwiches the fiber substrate between resin sheets (films); attaching powdered resin to the reinforced fiber substrate to improve impregnation; molding methods (Powder Impregnated Yarn) that use a fluidized bed or fluid slurry method in the process of mixing resin with the fiber substrate; and methods that blend resin fibers into the fiber substrate can also be used.

[0047] Examples of carbon fibers include acrylic, pitch, and rayon-based carbon fibers, with acrylic-based carbon fibers being preferred due to their high tensile strength. While twisted, untwisted, and untwisted forms of carbon fibers can be used, untwisted or untwisted yarns are preferred because they offer a good balance between the moldability and strength characteristics of the fiber-reinforced composite material.

[0048] The cured product of the curable resin composition of this embodiment can be used for various applications other than those described above, such as adhesives, paints, coatings, molding materials (including sheets, films, CFRP, rotor fixing members, etc.), encapsulants for semiconductor elements, encapsulants for liquid crystal display elements, encapsulants for organic EL elements, printed circuit boards (BGA substrates, build-up substrates, etc.), electrical and electronic components, 3D printing, and as additives to other resins.

[0049] The aforementioned adhesives include those for civil engineering, construction, automotive, general office, and medical applications, as well as adhesives for electronic materials. Among these, adhesives for electronic materials include interlayer adhesives for multilayer substrates such as Hibuildup substrates, die bonding agents, semiconductor adhesives such as underfills, underfills for BGA reinforcement, and adhesives for mounting such as anisotropic conductive films (ACF) and anisotropic conductive pastes (ACP), and are applicable to a wide range of uses.

[0050] When applying the curable resin composition of this embodiment to a semiconductor device encapsulant, the curable resin composition of this embodiment can be molded by placing a lead frame or semiconductor package substrate equipped with a semiconductor device into a mold, using a molten casting method, transfer molding method, injection molding method, compression molding method, etc., and then heating at 80 to 200°C for 2 to 10 hours to obtain a cured product. Examples of semiconductor devices manufactured using this encapsulant include potting, dipping, and transfer mold encapsulation for capacitors, transistors, diodes, light-emitting diodes, ICs, and LSIs; potting encapsulation for COB, COF, TAB, etc. of ICs and LSIs; underfill for flip chips; and encapsulation (including reinforcing underfill) when mounting IC packages such as QFP, BGA, and CSP.

[0051] When applying the curable resin composition of this embodiment to printed circuit board applications, a prepreg can also be obtained by heating and melting it to reduce its viscosity and impregnating it with reinforcing fibers such as glass fibers and polyamide fibers. Specific examples include, but are not limited to, glass fibers such as E glass cloth, D glass cloth, S glass cloth, Q glass cloth, spherical glass cloth, NE glass cloth, and T glass cloth, and / or organic fibers. The shape of the substrate is not particularly limited, but examples include woven fabrics, nonwoven fabrics, rovings, and chopped strand mats. As for the weaving method of the woven fabric, plain weave, twill weave, etc., are known, and these can be appropriately selected and used depending on the intended application and performance. Furthermore, glass woven fabrics that have been opened or surface-treated with silane coupling agents are preferably used. The thickness of the substrate is not particularly limited, but is preferably about 0.01 to 0.4 mm. Furthermore, a prepreg can be obtained by impregnating reinforcing fibers with the varnish and heating and drying it, and a copper-clad laminate (CCL) can be made from this prepreg. A laminate using the curable resin composition of this embodiment can also be made by hot-press molding the obtained prepreg and CCL. The laminate is not particularly limited as long as it has one or more prepregs, and may have any other layers. In addition, a sheet-like adhesive can be obtained by applying the varnish to a release film, removing the solvent under heating, and performing B-stage formation. This sheet-like adhesive can be used as an interlayer insulating layer in multilayer substrates or as an adhesive sheet when mounting semiconductors. Furthermore, the curable resin composition of this embodiment can be suitably used for special substrate materials such as package substrates and HDI (high-density interconnects).

[0052] When the curable resin composition of this embodiment is used for a rotor fixing member, the curable resin composition of this embodiment is placed in a mold for the rotor fixing member, molded by a molten casting method, transfer molding method, injection molding method, compression molding method, etc., and then heated at 80 to 200°C for 2 to 10 hours to obtain a cured product. [Examples]

[0053] The present invention will be described in more detail below with reference to synthesis examples and embodiments. The materials, processing content, processing procedures, etc., shown below can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below. Unless otherwise specified, parts refer to parts by weight.

[0054] The following conditions were used for various analytical methods. Epoxy equivalent The measurement was performed using the method described in JIS K-7236, and the unit is g / eq. ·Softening point The measurement was performed according to the method compliant with JIS K-7234, and the unit is °C. • Melt viscosity ICI melt viscosity (150°C) was measured using the cone-plate method, and the unit is Pa·s. • Biomass content analysis (accelerator gravimetric analysis) Measurements and calculations were performed in accordance with ASTM D6866-21. The unit is %, (%).

[0055] [Synthesis Example 1] In a flask equipped with a stirrer, reflux condenser, and stirring device, 254 parts by weight of phenol, 63 parts by weight of water, and 27 parts by weight of sodium hydroxide were charged, stirred, dissolved, and heated to 110°C. 44 parts by weight of furfural were then added dropwise over 2 hours. The mixture was then reacted at 110°C for 3 hours, and then the temperature was raised to 145°C. During the heating process, the water distilled out was removed from the system. After reaching 145°C, the mixture was reacted for 4 hours. The mixture was then cooled to 80°C, 63 parts by weight of water was added, and neutralization was performed by adding 4 parts by weight of phosphoric acid and 63 parts by weight of 35% hydrochloric acid. After repeated washing with water, the unreacted phenol was removed by distillation under reduced pressure to obtain 109 parts by weight of phenolic resin. To 78 parts by weight of the obtained phenolic resin, 254 parts by weight of epichlorohydrin (ECH, hereafter the same), 64 parts by weight of dimethyl sulfoxide (DMSO, hereafter the same), and 13 parts by weight of water were charged into a reaction vessel. After heating, stirring, and dissolution, 23 parts by weight of flake sodium hydroxide were added in installments over 2 hours while maintaining the temperature at 45°C. The reaction was then carried out further at 45°C for 2 hours and at 70°C for 60 minutes. After repeated washing with water to remove the by-product salts and dimethyl sulfoxide, excess epichlorohydrin was distilled off from the oil layer under heated reduced pressure, and 218 parts by weight of methyl isobutyl ketone was added to the residue and dissolved. This methyl isobutyl ketone solution was heated to 70°C, 7 parts by weight of a 30% sodium hydroxide aqueous solution was added, and the mixture was reacted for 1 hour. The reaction solution was then washed with water repeatedly until the washing solution became neutral. Next, methyl isobutyl ketone was distilled off from the oil layer under reduced pressure, yielding 97 parts by weight of epoxy resin A represented by formula (1). The epoxy equivalent was 214 g / eq., the softening point was 49°C, the ICI melt viscosity was 0.04 Pa·s, the average number of repeats n from GPC was 2.1, and the biomass content was 25%. The GPC chart for epoxy resin A is shown in Figure 1.

[0056] [Synthesis Example 2] Cashew-modified phenolic resin was synthesized in accordance with Japanese Patent Publication No. 2007-2032. In a flask equipped with a stirrer, reflux condenser, and stirring device, 250 parts by weight of phenol, 138 parts by weight of 37% formalin, 110 parts by weight of cashew oil, and 2 parts by weight of sulfuric acid were charged and reacted at 100°C under reflux for 1 hour. Subsequently, the temperature was raised to 190°C while performing vacuum distillation to obtain 254 parts by weight of cashew-modified phenolic resin. The softening point of this resin was 80°C and the biomass content was 31%.

[0057] [Example 1] Using epoxy resin A obtained in Synthesis Example 1 as the main component, lignin-modified phenolic resin (PLN-0051LP, manufactured by Aica Kogyo Co., Ltd., softening point 106°C, GPC chart shown in Figure 2) was added as a curing agent, and TPP (triphenylphosphine) was added as a curing accelerator in the weight ratios shown in Table 1. The mixture was then cured at 180°C for 6 hours to produce a cured product.

[0058] [Example 2] Using epoxy resin A obtained in Synthesis Example 1 as the main component, cashew-modified phenol resin obtained in Synthesis Example 2 as the curing agent, and TPP (triphenylphosphine) as the curing accelerator, the mixture was kneaded in the weight ratios shown in Table 1, and cured at 180°C for 6 hours to produce a cured product.

[0059] [Comparative Example 1] Using epoxy resin A obtained in Synthesis Example 1 as the main component, PN (phenol novolac resin, manufactured by Meiwa Kasei Co., Ltd., hydroxyl group equivalent 103 g / eq.) was added as a curing agent and TPP (triphenylphosphine) as a curing accelerator in the weight ratios shown in Table 1. The mixture was then cured at 180°C for 6 hours to produce a cured product.

[0060] The physical properties were measured under the following conditions. <Heat resistance (Tg) measurement conditions> Dynamic viscoelasticity measuring instrument: TA-instruments, DMA-Q800 Measurement temperature range: 25~300℃ Heating rate: 2°C / min Tg was defined as the peak point of Tg:Tanδ. <Dielectric constant and dielectric loss tangent tests> 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 2.5 mm wide x 50 mm long with a thickness of 0.3 mm. <Tensile modulus of elasticity, maximum tensile stress> Using the Autograph AGS-X from Shimadzu Corporation, the test specimen was clamped to a length of 5 cm and subjected to tensile testing at a tensile speed of 0.5 mm / min in a 180° direction.

[0061] [Table 1]

[0062] The results in Table 1 confirm that Examples 1 and 2 have a high biomass content and exhibit excellent high heat resistance, low dielectric properties, and mechanical strength.

Claims

1. A curable resin composition containing an epoxy resin represented by the following formula (1) and a lignin-modified phenol resin or a cashew-modified phenol resin. 【Chemistry 1】 (In equation (1), n ​​is the average value of the number of repetitions and represents a real number between 1 and 15.)

2. The curable resin composition according to claim 1, wherein the biomass content of the lignin-modified phenol resin or cashew-modified phenol resin is 20% or more.

3. The curable resin composition according to claim 1, wherein the ICI viscosity (150°C) of the epoxy resin is 0.01 to 0.20 Pa·s.

4. The curable resin composition according to claim 1, wherein the biomass content is 20% or more.

5. A curable resin composition according to any one of claims 1 to 4, for use with carbon fiber reinforced plastics.

6. A curable resin composition according to any one of claims 1 to 4, for use as a semiconductor device encapsulant.

7. A curable resin composition according to any one of claims 1 to 4, for use in printed circuit boards.

8. A cured product obtained by curing a curable resin composition according to any one of claims 1 to 4.

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