Maleimide compound, curable resin composition and cured product thereof, amine compound, and reaction product of amine compound and maleic anhydride

Abstract

This invention provides maleimide compounds with high heat resistance, excellent low dielectric properties and good curability, curable resin compositions and their cured products, as well as amine compounds as raw materials and reactants of amine compounds with maleic anhydride. The maleimide compounds are shown in the following formula (1). (In formula (1), multiple Rs exist independently and represent hydrocarbon groups or haloalkyl groups having 1 to 10 carbon atoms. X is shown in the following formula (2). m is an integer from 0 to 4, n is the number of repetitions, and n is the average value of n.) ave Satisfy 1≤n ave ≤20)(in formula (2), there are multiple Rs that exist independently and represent a hydrocarbon group or a haloalkyl group having 1 to 10 carbon atoms. p represents an integer from 0 to 4, and q represents an integer from 0 to 3. r is the number of repetitions, and the average value of r is r ave Satisfy 1≤r ave ≤20. * indicates the bonding position with the aromatic ring in the aforementioned formula (1).

Description

Technical Field

[0001] This invention relates to maleimide compounds, curable resin compositions and their cured products, as well as amine compounds and reactants of amine compounds and maleic anhydride, suitable for use in semiconductor sealing materials, printed circuit boards, laminates and other electrical and electronic components, lightweight and high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, and 3D printing applications. Background Technology

[0002] In recent years, the requirements for the characteristics of laminates that house electrical and electronic components have become more extensive and sophisticated due to the expanding applications. In the past, semiconductor chips were mainly mounted on metal lead frames, but semiconductor chips with higher processing power, such as central processing units (CPUs), are increasingly mounted on laminates made of polymer materials.

[0003] Next, in order to meet the heating characteristics of the heat-resistant laminate specifications, a heat resistance (Tg) of at least 160°C is required (Non-Patent Document 1).

[0004] Furthermore, the accelerated development of the fifth-generation communication system "5G" is expected to lead to greater capacity and higher speeds. This will further increase the demand for low-loss tangent materials, requiring a loss tangent of at least 0.005 at 10GHz.

[0005] Furthermore, the development of electronics in the automotive industry sometimes involves placing sophisticated electronic devices near the engine drive unit, thus requiring high levels of heat and moisture resistance. The use of SiC semiconductors in electric vehicles and air conditioning systems necessitates extremely high heat resistance in the sealing materials for these semiconductor components, which conventional epoxy resin sealants cannot meet.

[0006] In light of this background, polymeric materials that can combine heat resistance and low loss tangential properties have been explored. For example, Patent Document 1 proposes a composition comprising a maleimide resin and a phenolic resin containing an propylene group. Additionally, Patent Document 2 proposes an allyl ether resin with allyl groups replacing hydroxyl groups.

[0007] Furthermore, in recent years, 3D printing, as a three-dimensional modeling technique, has attracted considerable attention and is being applied in reliable fields such as aerospace, automotive, and connectors for electronic components used in these industries. In particular, photocurable and thermocurable resins are being examined for applications such as stereolithography (SLA) and digital light processing (DLP). Therefore, while traditional mold-transfer methods primarily require shape stability and accuracy, 3D printing applications demand various properties such as heat resistance, mechanical properties, toughness, flame retardancy, and electrical properties, leading to the development of related materials. Additionally, changes in properties due to moisture absorption are a challenge when used in structural components. Currently, acrylic resins or epoxy resins are used in these applications.

[0008] [Existing Technical Documents]

[0009] [Patent Literature]

[0010] Patent Document 1: Japanese Patent Application Publication No. 04-359911

[0011] Patent Document 2: International Publication No. 2016 / 002704.

[0012] [Non-patent literature]

[0013] Non-patent literature 1: Toshio Katayama, “Basic Lecture “Substrate Materials” No. 5, Heat-resistant Glass Epoxy Laminates”, Circuit Technology, The Japan Institute of Electronics Packaging, 1993, Vol. 8, No. 6, pp. 505-511. Summary of the Invention

[0014] [Problems to be Solved by the Invention]

[0015] However, in compositions containing maleimide resin and phenolic resin containing propylene groups, phenolic hydroxyl groups that do not participate in the reaction remain during the curing reaction, so the electrical properties are not considered sufficient.

[0016] In addition, in allyl ether resins where hydroxyl groups are replaced by allyl groups, Claisen rearrangement occurs at 190°C, and phenolic hydroxyl groups that do not participate in the curing reaction are generated at 200°C, which is the typical molding temperature of a substrate. Therefore, the electrical properties cannot be satisfied.

[0017] Furthermore, the cured acrylic or epoxy resins used in 3D printing contain a large number of ester bonds, ether bonds, and hydroxyl groups, and their hygroscopic properties are not sufficient.

[0018] The present invention was developed in view of this situation and aims to provide maleimide compounds with high heat resistance, excellent low dielectric properties and good curability, curable resin compositions and their cured products, as well as amine compounds as raw materials thereto and reactants of amine compounds with maleic anhydride.

[0019] [Methods used to solve problems]

[0020] That is, this invention relates to [1] to [8] below. In addition, in this invention, "(numerical value 1) to (numerical value 2)" indicates that it includes upper and lower limits.

[0021] [1] A maleimide compound represented by the following formula (1).

[0022]

[0023] In equation (1), multiple Rs exist independently and represent hydrocarbon groups or haloalkyl groups with 1 to 10 carbon atoms. X is shown in equation (2) below. m is an integer from 0 to 4, n is the number of repetitions, and the average value of n is n ave Satisfying 1≤n ave ≤20)

[0024]

[0025] In equation (2), multiple Rs exist independently and represent hydrocarbon groups or haloalkyl groups with 1 to 10 carbon atoms. p represents an integer from 0 to 4, and q represents an integer from 0 to 3. r is the repetition number, and r is the average value of r. ave Satisfying 1≤r ave ≤20. * indicates the bonding position with the aromatic ring in the aforementioned equation (1)

[0026] [2] A maleimide compound represented by the following formula (3).

[0027]

[0028] In equation (3), X is as shown in equation (4) below. n is the number of repetitions, and the average value of n is n ave Satisfying 1.1≤n ave ≤20)

[0029]

[0030] In equation (4), multiple R exist independently and represent hydrocarbon groups with 1 to 5 carbon atoms. p represents an integer from 0 to 4, r is the repetition number, and r is the average value of r. ave Satisfying 1.1≤r ave ≤20. * indicates the bonding position of the aromatic ring of the compound with formula (3).

[0031] [3] The maleimide compound as described in [2] above, wherein in the aforementioned formula (4), p is 2 and the substitution position of R is ortho to the maleimide group.

[0032] [4] A curable resin composition comprising any one of the maleimide compounds described in [1] to [3] above.

[0033] [5] The curable resin composition as described in [4] above also contains a free radical polymerization initiator.

[0034] [6] A hardened material obtained by hardening the hardening resin composition described in [4] or [5] above.

[0035] [7] An amine compound represented by the following formula (5).

[0036]

[0037] In equation (5), multiple Rs exist independently and represent hydrocarbon groups or haloalkyl groups with 1 to 10 carbon atoms. p represents an integer from 0 to 4, and q represents an integer from 0 to 3. r is the repetition number, and r is the average value of r. ave Satisfying 1≤r ave ≤20).

[0038] [8] A reactant is the reactant of the compound described in [7] above with maleic anhydride.

[0039] [Effects of the invention]

[0040] The cured maleimide compound of the present invention exhibits excellent properties such as high heat resistance and low dielectric properties. Therefore, it is a material that can be used for sealing electrical and electronic components, circuit boards, carbon fiber composites, etc. Attached Figure Description

[0041] Figure 1 The GPC diagram shows the amine compound of Example 1.

[0042] Figure 2 The image shows the GPC diagram of the maleimide compound from Example 1.

[0043] Figure 3 This refers to the maleimide compound of Example 1. 1 H-NMR spectrum.

[0044] Figure 4 The GPC diagram shows the amine compound of Example 2.

[0045] Figure 5 The GPC diagram shows the maleimide compound of Example 2.

[0046] Figure 6This refers to the maleimide compound of Example 2. 1 H-NMR spectrum.

[0047] Figure 7 The GPC diagram shows the amine compound synthesized in Example 1.

[0048] Figure 8 The GPC diagram shows the maleimide compound synthesized in Example 2. Detailed Implementation

[0049] The maleimide compound in this embodiment is shown in the following formula (1).

[0050]

[0051] In equation (1), multiple Rs exist independently and represent hydrocarbon groups or haloalkyl groups with 1 to 10 carbon atoms. X is shown in equation (2) below. m is an integer from 0 to 4, n is the number of repetitions, and the average value of n is n ave Satisfying 1≤n ave ≤20)

[0052]

[0053] In equation (2), multiple Rs exist independently and represent hydrocarbon groups or haloalkyl groups with 1 to 10 carbon atoms. p represents an integer from 0 to 4, and q represents an integer from 0 to 3. r is the repetition number, and r is the average value of r. ave Satisfying 1≤r ave ≤20. * indicates the bonding position with the aromatic ring in the aforementioned equation (1)

[0054] In the aforementioned formulas (1) and (2), R is a hydrocarbon group or haloalkyl group with 1 to 10 carbon atoms, more preferably a hydrocarbon group with 1 to 10 carbon atoms, more preferably a hydrocarbon group with 1 to 5 carbon atoms, and especially preferably a hydrocarbon group with 1 to 3 carbon atoms. When R has a small number of carbon atoms, molecular vibration becomes more difficult when exposed to high frequencies. Therefore, when R is a hydrocarbon group with 1 to 3 carbon atoms as described above, the electrical properties are particularly excellent.

[0055] In the aforementioned formula (1), m is usually an integer from 0 to 4, more preferably from 0 to 3, more preferably from 0 to 1, and especially preferably 0. n is the repetition number, and the average value of n is n ave Usually, 1 ≤ n ave ≤20, preferably satisfying 1.1≤n ave ≤20, more preferably 1.1≤n ave ≤18, preferably satisfying 1.1≤n ave ≤15. The average value of n. aveThe number average molecular weight (Mn) can be calculated from the value obtained by colloidal permeation chromatography (GPC) of the compound shown in formula (1). The number average molecular weight is preferably 200 or higher and less than 10,000, more preferably 1,000 or higher and less than 7,500, and most preferably 2,000 or higher and less than 5,000. If the number average molecular weight is less than 10,000, purification by washing with water is easier; if it is 200 or higher, the likelihood of the target compound volatilizing during the solvent removal step is lower.

[0056] In the aforementioned formula (2), p typically represents an integer from 0 to 4, more preferably from 0 to 3, and even more preferably from 0 to 2. q typically represents an integer from 0 to 3, more preferably from 0 to 2, even more preferably from 0 to 1, and especially preferably 0. r is the repetition number, and the average value of r is r ave Usually, 1 ≤ r is satisfied. ave ≤20, preferably satisfying 1.1≤r ave ≤20, and more preferably 1.1≤r ave ≤18, preferably satisfying 1.1≤r ave ≤15.

[0057] A preferred example of the maleimide compound shown in formula (1) is the maleimide compound shown in formula (3) below.

[0058]

[0059] In equation (3), X is as shown in equation (4) below. n is the number of repetitions, and the average value of n is n ave Satisfying 1.1≤n ave ≤20)

[0060]

[0061] In equation (4), multiple R exist independently and represent hydrocarbon groups with 1 to 5 carbon atoms. p represents an integer from 0 to 4, r is the repetition number, and r is the average value of r. ave Satisfying 1.1≤r ave ≤20. * indicates the bonding position of the aromatic ring of the compound with formula (3).

[0062] In the aforementioned formula (4), from the viewpoints of molecular weight control, solvent solubility, dielectric properties, low water absorption, and heat resistance, R is preferably substituted with two substituents at the ortho position of maleimide.

[0063] The maleimide compound shown in formula (1) can be obtained, for example, by reacting a polymer of the amine compound shown in formula (5) with maleic anhydride. The polymerization and maleimation reactions of the amine compound shown in formula (5) can be carried out separately, but the polymerization and maleimation reactions of the amine compound shown in formula (5) can be carried out in the presence of an acid catalyst such as methanesulfonic acid. The conditions for the maleimation reaction are not particularly limited. The solvents used can be, for example, aromatic solvents such as toluene and xylene, aliphatic solvents such as cyclohexane and n-hexane, ethers such as diethyl ether and diisopropyl ether, ester solvents such as ethyl acetate and butyl acetate, ketone solvents such as methyl isobutyl ketone and cyclopentanone, etc., but are not limited to these, and two or more solvents can be used together. In addition, aprotic polar solvents can be used in addition to the aforementioned aprotic solvents. Examples of suitable catalysts include dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidineone, and N-methylpyrrolidone, and two or more can be used in combination. When using aprotic polar solvents, it is preferable to use a solvent with a higher boiling point than the water-insoluble solvent used in combination. Hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, p-toluenesulfonic acid, and methanesulfonic acid can be used as catalysts during the reaction. Additionally, Lewis acids such as aluminum chloride and zinc chloride, activated clay, acid clay, white carbon, zeolite, silica, and alumina, as well as acidic ion exchange resins, can be used. These can be used alone or in combination. The amount of catalyst used is typically 0.1 to 0.8 moles relative to 1 mole of the amine group of the amine compound used, preferably 0.2 to 0.7 moles. Excessive catalyst usage may result in excessively high viscosity of the reaction solution, making stirring difficult; insufficient catalyst usage may slow down the reaction. Alternatively, basic co-catalysts such as triethylamine, which are imidized, can be used alone or in combination with other co-catalysts. When using sulfonic acid or similar catalysts, neutralization with alkali metals such as sodium hydroxide or potassium hydroxide can be performed before the extraction step. The extraction step can use aromatic hydrocarbon solvents such as toluene or xylene alone, or in combination with non-aromatic hydrocarbons such as cyclohexane or toluene. After extraction, the organic layer is washed with water until the wastewater becomes neutral, and the solvent is removed by distillation using an evaporator or similar method, thereby obtaining the desired maleimide compound.

[0064]

[0065] In equation (5), multiple Rs exist independently and represent hydrocarbon groups or haloalkyl groups with 1 to 10 carbon atoms. p represents an integer from 0 to 4, and q represents an integer from 0 to 3. r is the repetition number, and r is the average value of r. ave Satisfying 1≤r ave ≤20).

[0066] The definition of R in the aforementioned equation (5), and p, q, r ave The preferred range is the same as that in equation (2) above.

[0067] In the aforementioned formula (5), from the viewpoints of molecular weight control, solvent solubility, dielectric properties, low water absorption, and heat resistance, in the benzene ring with amine bonds, it is particularly preferred that p=2 and the substitution position of R is at the 2 ortho positions of the amine group.

[0068] The softening point of the amine compound shown in formula (5) is preferably below 120°C, and more preferably below 110°C. If the softening point is below 120°C, the viscosity of the maleimide compound derived from formula (1) is lower. This makes it easier to ensure the flowability of the curable resin composition, and the curable resin composition can be easily pre-impregnated or otherwise made into a semi-cured state (B-stage) without compromising its impregnation properties with fibrous materials such as glass cloth or carbon fiber. The viscosity of the curable resin composition can be reduced by increasing the diluent, but in this case, the curable resin composition may not be able to fully adhere to fibrous materials during the impregnation step. Therefore, it is preferable that the softening point of the amine compound shown in formula (5) is below 120°C.

[0069] The amine compound represented by formula (5) above can be obtained, for example, by reacting diisopropenylbenzene (or α,α,α',α'-tetramethylbenzenedimethanol) with aniline in the presence of an acid catalyst. In this case, the substituents of the aniline compound are preferably unsubstituted or have alkyl groups having 1 to 5 carbon atoms. From the viewpoints of molecular weight control, solvent solubility, dielectric properties, low water absorption, and heat resistance, unsubstituted or having two alkyl groups having 1 to 3 carbon atoms or adjacent to the benzene ring to which the amine group is bonded are more preferably unsubstituted.

[0070] In the synthesis, liquid acid catalysts such as hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, p-toluenesulfonic acid, and methanesulfonic acid can be used. Additionally, solid acid catalysts such as Lewis acids (aluminum chloride, zinc chloride, etc.), activated clay, acid clay, white carbon, zeolite, silica-alumina, and acidic ion exchange resins can be used. These acid catalysts can be used alone or in combination of two or more. The amount of acid catalyst used relative to the total weight of the reaction matrix diisopropenylbenzene (or α,α,α',α'-tetramethylbenzenedimethanol) and aniline is 0.01 to 50% by weight, preferably 0.1 to 35% by weight. Excessive use of acid catalyst raises concerns about increased waste, while insufficient use may slow down the reaction. 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 and butyl acetate, and ketone solvents such as methyl isobutyl ketone and cyclopentanone, which are non-water-soluble solvents. However, these are not limited to these, and two or more solvents may be used in combination. In addition to the aforementioned non-water-soluble solvents, aprotic polar solvents may also be used in combination. Examples include dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidineone, and N-methylpyrrolidone, and two or more of these may also be used in combination. When using aprotic polar solvents, it is preferable to use solvents with a higher boiling point than the non-water-soluble solvents used in combination. The reaction temperature is preferably 80 to 250°C, more preferably 90 to 240°C, and even more preferably 100 to 230°C. If the reaction temperature is too high, it may cause a useless thermal decomposition reaction; if the reaction temperature is too low, there is a concern that the reaction may not proceed sufficiently. When using α,α,α',α'-tetramethylbenzyldiethanol as a raw material, or when using an acid catalyst containing water, the generated water or water in the system is azeotropically reacted with the solvent during heating and removed from the system. After the reaction is complete, the acid catalyst is neutralized with an alkaline aqueous solution, and a non-water-soluble organic solvent is added to the oil layer. The mixture is repeatedly washed with water until the wastewater becomes neutral, and then the solvent is removed under reduced pressure. When using activated clay or ion exchange resin, the reaction solution can be filtered after the reaction to remove the acid catalyst.

[0071] Examples of the aforementioned anilines include aniline, o-methylaniline, m-methylaniline, p-methylaniline, o-ethylaniline, m-ethylaniline, p-ethylaniline, o-propylaniline, m-propylaniline, p-propylaniline, o-isopropylaniline, m-isopropylaniline, p-isopropylaniline, 2,6-dimethylaniline, 2,6-diethylaniline, 2,6-dipropylaniline, 2,6-isopropylaniline, 2-ethyl-6-methylaniline, 2-propyl-6-methylaniline, 2-isopropyl-6-methylaniline, 2-ethyl-6-propylaniline, and 2-ethyl-6-isopropylaniline, but are not limited to these. These can be used alone or in combination of two or more. If the number of carbon atoms is large, the solvent solubility will be improved, but the heat resistance will be reduced. Therefore, it is more preferable to have no substitution or to be substituted with alkyl groups having 1 to 3 carbon atoms, more preferably to have no substitution or to be substituted with alkyl groups having 1 to 2 carbon atoms, and most preferably to have no substitution or to be substituted with methyl groups.

[0072] Examples of the aforementioned diisopropylbenzene include 1,2-diisopropylbenzene, 1,3-diisopropylbenzene, 1,4-diisopropylbenzene, and their alkyl-substituted derivatives.

[0073] Examples of the aforementioned α,α,α',α'-tetramethylbenzyl alcohols include α,α,α',α'-tetramethyl-1,2-benzyl alcohol, α,α,α',α'-tetramethyl-1,3-benzyl alcohol, α,α,α',α'-tetramethyl-1,4-benzyl alcohol, and their alkyl-substituted derivatives.

[0074] The aforementioned diisopropenylbenzene and the aforementioned α,α,α',α'-tetramethylbenzyldiethanol can be used alone or in combination of two or more. The amount used is preferably 1.0 to 10 moles relative to 1 mole of the amino group of aniline, more preferably 1.0 to 7.5 moles, and even more preferably 1.0 to 5.0 moles.

[0075] [Polymerization initiator]

[0076] The curable resin composition of this embodiment can also have its curability improved by adding a polymerization initiator. The polymerization initiator is a compound that can polymerize olefin functional groups such as ethylene unsaturated bonds; examples include olefin transposition polymerization initiators, anionic polymerization initiators, cationic polymerization initiators, and free radical polymerization initiators. Free radical polymerization initiators, which possess both curability and moderate stability, are preferred. Olefin transposition polymerization initiators such as Schrock catalysts with molybdenum as the central metal, anionic polymerization initiators such as n-butyllithium (n-BuLi), or cationic polymerization initiators such as triethylaluminum, exhibit poor stability due to reactions with moisture in the air.

[0077] Free radical polymerization initiators are compounds that generate free radicals and initiate chain polymerization reactions by irradiation with ultraviolet or visible light or heating. Examples of usable free radical polymerization initiators include organic peroxides, azo compounds, and benzopinnatols. Considering the need to control the curing temperature and minimize the impact of gas release and decomposition products on electrical properties, organic peroxides are preferred.

[0078] Examples of the aforementioned organic peroxides include ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide; diacyl peroxides such as benzoyl peroxide; dialkyl peroxides such as diisopropylbenzene peroxide and 1,3-bis-(tert-butylperoxyisopropyl)benzene; peroxyketals such as tert-butyl peroxide and 1,1-di-tert-butylperoxycyclohexane; α-isopropylphenyl peroxyneodecanoate; tert-butyl peroxyneodecanoate; tert-butyl peroxyneodecanoate; 1,1,3,3-tetramethylbutyl peroxyneodecanoate; and 2-ethylhexanoate peroxide. Alkyl peroxides such as tert-amyl peroxide, tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, and tert-amyl peroxybenzoate; peroxides such as di-2-ethylhexyl peroxydicarbonate, bis(4-tert-butylcyclohexyl) peroxydicarbonate, tert-butyl peroxyisopropyl carbonate, and 1,6-bis(tert-butylperoxycarbonyloxy)hexane; tert-butyl hydroperoxide; cumene hydroperoxide; tert-butyl peroxyoctanoate; and lauroyl peroxide, but not limited to these. Furthermore, one or more of these can be used. Ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peroxides, and peroxycarbonates are more preferred among the above-mentioned organic peroxides.

[0079] Examples of the aforementioned azo compounds include azobisisobutyronitrile, 4,4'-azobis(4-cyanopentaic acid), and 2,2'-azobis(2,4-dimethylpentanonitrile), but they are not limited to these. Furthermore, one or more of these compounds may be used.

[0080] When the total amount of non-volatile components excluding inorganic fillers (fillers) in the curing resin composition is 100 parts by mass, the amount of polymerization initiator added is preferably 0.01 to 5 parts by mass, and more preferably 0.01 to 3 parts by mass. If the amount of polymerization initiator used is less than 0.01 parts by mass, there is a concern that the molecular weight may not be sufficiently elongated during the polymerization reaction; if it is more than 5 parts by mass, there is a concern that the dielectric constant, loss tangent, and other dielectric properties may be impaired.

[0081] [Polymerization inhibitor]

[0082] The curable resin composition of this embodiment may contain a polymerization inhibitor. Containing a polymerization inhibitor improves storage stability and allows for control of the reaction initiation temperature. Controlling the reaction initiation temperature makes it easier to ensure the flowability of the curable resin composition, facilitating B-stage processes such as prepreg forming without compromising impregnation with fibrous materials such as glass cloth or carbon fibers. If the polymerization reaction is excessive during prepreg forming, problems such as lamination difficulties can easily occur in the lamination steps.

[0083] The polymerization inhibitor may be added during the synthesis of the compound shown in formula (1) or after the synthesis. The amount of polymerization inhibitor used is 0.008 to 1 part by weight relative to 100 parts by weight of the compound shown in formula (1), preferably 0.01 to 0.5 parts by weight.

[0084] Examples of polymerization inhibitors include phenolic, sulfur-based, phosphorus-based, hindered amine-based, nitroso-based, and nitroxide-radical-based inhibitors. Furthermore, one or more inhibitors may be used. Among these, phenolic, hindered amine, nitroso-based, and nitroxide-radical-based inhibitors are preferred in this embodiment.

[0085] Examples of the aforementioned phenolic polymerization inhibitors include 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-p-ethylphenol, stearyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, isooctyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-trimethylaniline. Monophenols such as 2,4-bis[(octylthio)methyl]-o-cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 4,4'-butylenebis(3-methyl-6-tert-butylphenol), and triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxy] [3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrogenated cinnamamide), 2,2-thio-diethylidenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 3,5-di-tert-butyl-4-hydroxybenzyl phosphate diethyl ester, 3,9-bis[1, 1-Dimethyl-2-{β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane, bis(3,5-di-tert-butyl-4-hydroxybenzylsulfonate ethyl ester) calcium and other bisphenols, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5- Di-tert-butyl-4-hydroxybenzyl)benzene, tetra-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-tert-butylphenyl)butyrate]diol ester, tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-triisocyanate, 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-S-tris- The list includes high molecular weight phenols such as -2,4,6-(1H,3H,5H)triones and tocopherols, but is not limited to these.

[0086] Examples of sulfur-based polymerization inhibitors include dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, and distearate-3,3'-thiodipropionate, but they are not limited to these.

[0087] Examples of the aforementioned phosphorus-based polymerization inhibitors include triphenyl phosphite, diphenyl isodecanyl phosphite, phenyl diisodecyl phosphite, tri(nonylphenyl) phosphite, diisodecyl pentaerythritol phosphite, tris(2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetrayl bis(octadecyl) phosphite, cyclic neopentanetetrayl bis(2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetrayl bis(2,4-di-tert-butyl-4-methylphenyl) phosphite, and bis[2-tert-butyl-6-methylphenyl] phosphite. Phosphites such as methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl]hydrophosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-tert-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decoxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and oxaphosphaphenanthrene oxides, etc., but not limited to these.

[0088] Examples of the hindered amine polymerization inhibitors mentioned above include ADK STAB LA-40MP, ADK STAB LA-40Si, ADK STAB LA-402AF, ADK STAB LA-87, ADK STAB LA-82, ADK STAB LA-81, ADK STAB LA-77Y, ADK STAB LA-77G, ADK STAB LA-72, ADK STAB LA-68, ADK STAB LA-63P, ADK STAB LA-57, and ADK STAB. LA-52, Chimassorb2020FDL, Chimassorb944FDL, Chimassorb944LD, Tinuvin622SF, TinuvinPA144, Tinuvin765, Tinuvin770DF, TinuvinXT55FB, Tinuvin111FDL, Tinuvin783FDL, Tinuvin791FB, etc., but not limited to these.

[0089] Examples of the aforementioned nitrosyl-based polymerization inhibitors include, but are not limited to, ammonium salts of p-nitrosophenol, N-nitrosodiphenylamine, and N-nitrosophenylhydroxylamine (copper ferrol). Among these, ammonium salts of N-nitrosophenylhydroxylamine (copper ferrol) are preferred.

[0090] Examples of the aforementioned nitrogen oxide free radical polymerization inhibitors include di-tert-butyl oxynitride, 2,2,6,6-tetramethylpiperidine-1-oxide, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxide, 4-sideoxy-2,2,6,6-tetramethylpiperidine-1-oxide, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxide, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxide, 4-acetoxy-2,2,6,6-tetramethylpiperidine-1-oxide, and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxide, but they are not limited to these.

[0091] [Inorganic filler]

[0092] The curable resin composition of this embodiment may contain inorganic fillers. Examples of inorganic fillers include, for example, fused silica, crystalline silica, porous silica, alumina, zircon, calcium silicate, calcium carbonate, quartz powder, silicon carbide, silicon nitride, boron nitride, zirconium dioxide, aluminum nitride, graphite, forsterite, block talc, spinel, aluminum-rich andalusite, titanium dioxide, talc, clay, iron oxide asbestos, glass powder, etc., or inorganic fillers formed into spherical or fragmented shapes, but are not limited to these. Furthermore, one or more of these fillers may be used.

[0093] When obtaining a curable resin composition for semiconductor sealing, the amount of inorganic filler used is preferably 80 to 92 parts by weight, and more preferably 83 to 90 parts by weight, out of 100 parts by weight of the curable resin composition. Furthermore, when obtaining a curable resin composition for interlayer insulating layer forming materials, copper foil laminates or prepregs, RCC and other substrate materials, the amount of the aforementioned inorganic filler used is preferably 5 to 80 parts by weight, and more preferably 10 to 60 parts by weight, out of 100 parts by weight of the curable resin composition.

[0094] [Hardening Accelerator]

[0095] The curing properties of the curable resin composition of this embodiment can also be improved by adding a curing accelerator. The curing accelerator is preferably an anionic curing accelerator that generates anions to promote the curing reaction by irradiation with ultraviolet or visible light or by heating, or a cationic curing accelerator that generates cations to promote the curing reaction by irradiation with ultraviolet or visible light or by heating.

[0096] Examples of anionic hardening accelerators include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole; trialkylamines such as triethylamine and tributylamine; 4-dimethylaminopyridine; benzyldimethylamine; 2,4,6-tris(dimethylaminomethyl)phenol; and 1,8-diazabicyclo(5,4,0)-undecene, with 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene being more preferred. Other examples include phosphines such as triphenylphosphine; quaternary ammonium salts such as tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecylammonium salt, cetyltrimethylammonium salt, and hexadecyltrimethylammonium hydroxide.

[0097] Examples of cationic hardening accelerators include quaternary phosphonium salts such as triphenylbenzylphosphonium salt, triphenylethylphosphonium salt, and tetrabutylphosphonium salt (the relative ions of the quaternary salts are halogen ions, organic acid ions, hydroxide ions, etc., without particular specification, but organic acid ions and hydroxide ions are particularly preferred), tin octoate, zinc carboxylate (zinc 2-ethylhexanoate, zinc stearate, zinc docosinate, zinc myristate), and zinc phosphate esters (zinc octyl phosphate, zinc stearyl phosphate), etc., but are not limited to these. Furthermore, one or more of these can be used.

[0098] The curing accelerator is optionally added in an amount of 0.01 to 5.0 parts by weight relative to 100 parts by weight of the total non-volatile components excluding inorganic fillers (fillers) in the curing resin composition.

[0099] [Flame retardant]

[0100] Flame retardants can also be used in the curable resin composition of this embodiment. 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. From the viewpoint of achieving halogen-free flame retardancy, phosphorus-based flame retardants are preferred.

[0101] The aforementioned phosphorus-based flame retardants can be reactive or additive. Specific examples include phosphate esters such as trimethyl phosphate, triethyl phosphate, tricresyl phosphate, tri(xyl) phosphate, cresol diphenyl phosphate, cresol-di-2,6-xylyl phosphate, 1,3-phenylenebis(bisxylyl phosphate), 1,4-phenylenebis(bisxylyl phosphate), and 4,4'-biphenyl(bisxylyl phosphate); phosphine derivatives 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 phosphine derivatives; and red phosphorus, but are not limited to these. Furthermore, one or more of these can be used in combination. The substances exemplified above are preferably phosphate esters, phosphines, or phosphorus-containing epoxy compounds, and particularly preferably 1,3-phenylenebis(bis-xylyl phosphate), 1,4-phenylenebis(bis-xylyl phosphate), 4,4'-biphenyl(bis-xylyl phosphate), or phosphorus-containing epoxy compounds.

[0102] When the total amount of non-volatile components excluding inorganic fillers (fillers) in the curing resin composition is 100 parts by weight, the flame retardant content is preferably in the range of 0.1 to 0.6 parts by weight. At 0.1 parts by weight, there is concern that the flame retardancy may be insufficient; if it exceeds 0.6 parts by weight, there is concern that it may adversely affect the hygroscopicity and dielectric properties of the cured material.

[0103] [Light stabilizer]

[0104] The curable resin composition of this embodiment may also use a light stabilizer. The light stabilizer is preferably a hindered amine-based light stabilizer, and particularly preferably HALS. Examples of HALS include dibutylamine and 1,3,5-trimethylamine. The reaction product of N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl-1,6-hexamethylenediamine with N-(2,2,6,6-tetramethyl-4-piperidinyl)butylamine, the reaction product of dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine, and poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-trimethyl... The following are examples of bis(1,2,2,6,6-pentamethyl-4-piperidinyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidinyl)imino}, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl] butyl malonate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-n-butylmalonic acid bis(1,2,2,6,6-pentamethyl-4-piperidinyl), etc., but are not limited to these. In addition, these can be used in one or in combination.

[0105] When the total amount of non-volatile components excluding inorganic fillers (fillers) in the curing resin composition is 100 parts by weight, the content of the light stabilizer is preferably in the range of 0.001 to 10 parts by weight. If it is less than 0.001 parts by weight, there is a concern that the light stabilizing effect may not be sufficient, and if it is more than 10 parts by weight, there is a concern that it may adversely affect the hygroscopicity and dielectric properties of the cured material.

[0106] [Adhesive Resin]

[0107] The curable resin composition of this embodiment may also use an adhesive resin. Examples of adhesive resins include butyraldehyde resins, acetal resins, acrylic resins, epoxy-nylon resins, NBR-phenol resins, epoxy-NBR resins, polysiloxane resins, etc., but are not limited to these. In addition, one or more of these may be used.

[0108] The amount of adhesive resin is preferably within a range that does not impair the flame retardancy and heat resistance of the cured product. When the total amount of non-volatile components excluding inorganic fillers (fillers) in the cured resin composition is 100 parts by weight, it is preferably 0.05 to 50 parts by weight, and more preferably 0.05 to 20 parts by weight.

[0109] [additive]

[0110] Additives may also be used in the curable resin composition of this embodiment. Examples of additives include modified acrylonitrile copolymers, polyethylene, fluororesins, polysiloxane gels, polysiloxane oils, surface treatment agents for silane coupling agents and other fillers, release agents, carbon black, phthalocyanine blue, phthalocyanine green and other colorants.

[0111] The amount of additive is preferably 1,000 parts by weight or less, and more preferably 700 parts by weight or less, relative to 100 parts by weight of the curing resin composition.

[0112] The curable resin composition of this embodiment can further utilize epoxy resin, reactive ester compound, phenolic resin, amine resin, maleimide compound, compound having vinyl unsaturated bonds, isocyanate resin, polyamide resin, polyimide resin, cyanate ester resin, polyphenylene ether compound, polybutadiene and its modified forms, polystyrene and its modified forms, etc., and one or more of these can be used. Among these compounds, considering the balance of heat resistance, adhesion, and dielectric properties, compounds having vinyl unsaturated bonds, cyanate ester resins, polyphenylene ether compounds, polybutadiene and its modified forms, and polystyrene and its modified forms are more preferred. By containing these compounds, the brittleness of the cured product can be improved and the adhesion to metals can be enhanced, and the cracking of the package can be suppressed during solder reflow or reliability tests such as thermal cycling.

[0113] Unless otherwise specified, the amount of the compound used relative to the compound shown in formula (1) is preferably 10 times or less by mass, more preferably 5 times or less by mass, and particularly preferably 3 times or less by mass. Furthermore, the lower limit is preferably 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 the above range, the heat resistance or dielectric properties of the compound shown in formula (1) can be achieved, and the effects of each added compound can be further enhanced. Examples of these components are shown below.

[0114] [Epoxy Resin]

[0115] The following examples are preferred embodiments of epoxy resins, but are not limited to these. Furthermore, the epoxy resin may be in liquid or solid form, and one or more types may be used.

[0116] Examples of liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, epoxy propylene ester type epoxy resin, epoxy propylene amine type epoxy resin, phenolic varnish type epoxy resin, alicyclic epoxy resin with ester skeleton, cyclohexane type epoxy resin, cyclohexanediethanol type epoxy resin, and epoxy resin with butadiene structure. Specific examples include “RE310S”, “RE410S” (these are bisphenol A type epoxy resins manufactured by Nippon Kayaku Co., Ltd.), “RE303S”, “RE304S”, “RE403S”, “RE404S” (these are bisphenol F type epoxy resins manufactured by Nippon Kayaku Co., Ltd.), “HP4032”, “HP4032D”, “HP4032SS” (these are naphthalene type epoxy resins manufactured by DIC Corporation), “828US”, “jER828EL”, “825”, “828EL” (these are bisphenol A type epoxy resins manufactured by Mitsubishi Chemical Co., Ltd.). Epoxy resins, including "jE807", "1750" (the above are bisphenol F type epoxy resins manufactured by Mitsubishi Chemical Corporation), "jER152" (phenolic varnish type epoxy resins manufactured by Mitsubishi Chemical Corporation), "630", "630LSD" (the above are epoxy propylene amine type epoxy resins manufactured by Mitsubishi Chemical Corporation), "ZX1059" (a mixture of bisphenol A type epoxy resins and bisphenol F type epoxy resins manufactured by Nippon Steel & Sumitomo Metal Chemicals Corporation), "EX-721" (epoxy propylene ester type epoxy resins manufactured by Nagasechemtex Corporation), "Celloxide 2021P" (alicyclic epoxy resins with an ester skeleton manufactured by Daicel Corporation), "PB-3600" (epoxy resins with a butadiene structure manufactured by Daicel Corporation), "ZX1658", "ZX1658GS" (the above are liquid 1,4-epoxypropylcyclohexane type epoxy resins manufactured by Nippon Steel & Sumitomo Metal Chemicals Corporation), etc. These can be used individually or in combination of two or more.

[0117] Solid epoxy resins are preferably, for example, xylenol-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type tetrafunctional epoxy resin, cresol phenolic varnish-type epoxy resin, dicyclopentadiene-type epoxy resin, triphenol-type epoxy resin, naphthol-type epoxy resin, biphenyl-type epoxy resin, naphthyl ether-type epoxy resin, anthracene-type epoxy resin, bisphenol A-type epoxy resin, bisphenol AF-type epoxy resin, and tetraphenylethane-type epoxy resin. Examples include naphthol-type epoxy resin, bisphenol AF-type epoxy resin, naphthalene-type epoxy resin, and biphenyl-type epoxy resin. Specific examples include "HP4032H" (naphthalene-based epoxy resin manufactured by DIC), "HP-4700", "HP-4710" (the above are naphthalene-based tetrafunctional epoxy resins manufactured by DIC), "N-690" (cresol-phenolic varnish-type epoxy resin manufactured by DIC), "N-695" (cresol-phenolic varnish-type epoxy resin manufactured by DIC), "HP-7200" (dicyclopentadiene-type epoxy resin manufactured by DIC), "HP-7200", "HP-7200HH", and "HP-7200H" (the above are dicyclopentadiene-type epoxy resins manufactured by DIC). Epoxy resins), "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP-6000" (the above are naphthyl ether type epoxy resins manufactured by DIC), "EPPN-502H" (triphenol type epoxy resins manufactured by Nippon Kayaku Co., Ltd.), "NC-7000L", "NC-7300" (the above are naphthol-cresol phenolic varnish type epoxy resins manufactured by Nippon Kayaku Co., Ltd.), "NC-3000H", "NC-3000", "NC-3000L", "NC-3 100 (the above are biphenyl aralkyl type epoxy resins manufactured by Nippon Chemical Co., Ltd.), "XD-1000-2L", "XD-1000-L", "XD-1000-H" (the above are dicyclopentadiene type epoxy resins manufactured by Nippon Chemical Co., Ltd.), "ESN475V" (naphthol type epoxy resins manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), "ESN485" (naphthol phenolic varnish type epoxy resins manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), "YX-4000H", "YX-4000", "YL6121" (the above are biphenyl type epoxy resins manufactured by Mitsubishi Chemical Co., Ltd.), "YX The following epoxy resins are available: "-4000HK" (bis(xylenol) type epoxy resin manufactured by Mitsubishi Chemical Corporation), "YX-8800" (anthracene type epoxy resin manufactured by Mitsubishi Chemical Corporation), "PG-100", "CG-500" (fluorene-based epoxy resin manufactured by Osaka Gas Chemical Co., Ltd.), "YL-7760" (bisphenol AF type epoxy resin manufactured by Mitsubishi Chemical Corporation), "YL-7800" (fluorene type epoxy resin manufactured by Mitsubishi Chemical Corporation), "jER1010" (solid bisphenol A type epoxy resin manufactured by Mitsubishi Chemical Corporation), and "jER1031S" (tetraphenylethane type epoxy resin manufactured by Mitsubishi Chemical Corporation). These can be used individually or in combination of two or more.

[0118] [Active ester compounds]

[0119] An active ester compound is a compound whose structure contains at least one ester bond and is flanked by an aliphatic chain, aliphatic ring, or aromatic ring. Examples of active ester compounds include phenolic esters, thiophenolic esters, N-hydroxyamine esters, and esters of heterocyclic hydroxyl compounds, which are compounds with two or more highly reactive ester groups per molecule. They can be obtained through a condensation reaction of at least one carboxylic acid compound, acyl chloride, or thiocarboxylic acid compound with at least one hydroxyl compound or thiol compound. From the viewpoint of improving heat resistance, the case obtained by reacting a carboxylic acid compound or acyl chloride with a hydroxyl compound is preferred; the hydroxyl compound is preferably a phenolic compound or a naphthol compound. Active ester compounds can be used alone or in combination of two or more.

[0120] Examples of the aforementioned carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, isophthalic acid, terephthalic acid, and pyrocyanic acid.

[0121] Examples of the aforementioned acyl chlorides include acetyl chloride, acryloyl chloride, methacryloyl chloride, malonyl chloride, succinyl dichloride, 2,2'-oxydiacetyl chloride, glutaryl dichloride, octanoyl dichloride, sebacyl dichloride, adipyl dichloride, dodecyl dichloride, azelaic chloride, 2,5-furandicarboxyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesoyl chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarboxyl chloride, and 4,4'-azodibenzoyl chloride.

[0122] Examples of the aforementioned phenolic compounds and naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, acid phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthol, 1,6-dihydroxynaphthol, 2,6-dihydroxynaphthol, dihydroxydiphenyl ketone, trihydroxydiphenyl ketone, tetrahydroxydiphenyl ketone, phloroglucinol, phenylglycerol, dicyclopentadiene-type diphenol compounds, phenolic varnishes, and phenolic resins described later. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

[0123] Preferred examples of active ester compounds include active ester compounds containing a dicyclopentadiene-type diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated form of phenolic varnish, active ester compounds containing a benzoyl form of phenolic varnish, the compound described in Example 2 of International Publication No. 2020 / 095829, and the compound disclosed in International Publication No. 2020 / 059625. More preferred examples are active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene-type diphenol structure. The dicyclopentadiene-type diphenol structure represents a divalent structural unit composed of phenylene-dicyclopentylene-phenylene.

[0124] Commercially available active ester compounds include, for example, those containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", "HPC-8000H-65TM", "EXB-8000L-65TM", and "EXB-8150-65T" (manufactured by DIC), and those containing a naphthalene structure such as "EXB9416-70BK" (manufactured by DIC). Examples of active ester compounds containing acetylated compounds in phenolic varnishes include "DC808" (manufactured by Mitsubishi Chemical Corporation); examples of active ester compounds containing benzoyl compounds in phenolic varnishes include "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation); examples of active ester curing agents containing acetylated compounds in phenolic varnishes include "DC808" (manufactured by Mitsubishi Chemical Corporation); and examples of active ester curing agents containing phosphorus atoms include "EXB-9050L-62M" manufactured by DIC Corporation.

[0125] Regarding the blending ratio of the reactive ester compound and the epoxy resin, the ratio (α / β) of the reactive ester equivalent (α) to the epoxy group equivalent (β) is preferably 0.5 to 1.5, more preferably 0.8 to 1.2, and even more preferably 0.90 to 1.10. Beyond these ranges, there are concerns about excess epoxy groups or reactive ester groups remaining in the system, and concerns about property degradation during high-temperature storage tests (150°C, 1000 hours, etc.) or long-term reliability tests under high-temperature and high-humidity conditions (temperature: 85°C, humidity: 85%, etc.).

[0126] [Phenolic resin]

[0127] Phenolic resins refer to compounds with two or more phenolic hydroxyl groups within their molecules. Examples of phenolic resins include reactants of phenols and aldehydes, reactants of phenols and dienes, reactants of phenols and ketones, reactants of phenols and substituted biphenyls, reactants of phenols and substituted phenyl groups, and reactants of bisphenols and aldehydes, but are not limited to these. Furthermore, one or more of these can be used.

[0128] The following are specific examples of the above-mentioned raw materials, but are not limited to these.

[0129] <Phenolic compounds>

[0130] Phenols, alkyl-substituted phenols, aromatic-substituted phenols, hydroquinone, resorcinol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.

[0131] Aldehydes

[0132] Formaldehyde, acetaldehyde, alkyl aldehydes, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthal, glutaraldehyde, o-phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural, etc.

[0133] <Diene Compounds>

[0134] Dicyclopentadiene, terpenes, vinylcyclohexene, norcamphexene, vinylnorcamphexene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc.

[0135] Ketones

[0136] Acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, diphenyl ketone, fluorene, etc.

[0137] <Substituted biphenyls>

[0138] 4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, 4,4'-bis(hydroxymethyl)-1,1'-biphenyl, etc.

[0139] <Substituted benzene>

[0140] 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene, etc.

[0141] [Amine resin]

[0142] Amine resins are compounds with two or more amine groups within their molecules. Examples of amine resins include diaminodiphenylmethane, diaminodiphenyl sulfone, isophorone diamine, naphthyldiamine, aniline phenolic varnish (a product of the reaction of aniline and formalin), N-methylaniline phenolic varnish (a product of the reaction of N-methylaniline and formalin), o-ethylaniline phenolic varnish (a product of the reaction of o-ethylaniline and formalin), 2-methylaniline reacting with formalin, 2,6-diisopropylaniline reacting with formalin, 2,6-diethylaniline reacting with formalin, 2-ethyl-6-ethylaniline reacting with formalin, 2,6-dimethylaniline reacting with formalin, and resins obtained by the reaction of aniline with xylene chloride. The aniline resin, the reaction product of aniline with substituted biphenyls (such as 4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl, as described in Japanese Patent No. 6429862, the reaction product of aniline with substituted phenyls (such as 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene, 4,4'-(1,3-phenylene diisopropylidene)bisaniline, 4,4'-(1,4-phenylene diisopropylidene)bisaniline, the reaction product of aniline with diisopropylbenzene, and dimeric diamines, etc., are not limited to these. Furthermore, one or more of these can be used.

[0143] [Maleimide compounds other than those shown in formula (1)]

[0144] Maleimide compounds are compounds having one or more maleimide groups within their molecules. The curable resin composition of this embodiment may also contain maleimide compounds other than the maleimide compound shown in formula (1). Examples of maleimide compounds other than those shown in formula (1) include 4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, 2,2'-bis[4-(4-maleimide phenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-epoxyphenyl bismaleimide, 4,4'-diphenyl ether bismaleimide, 4,4'-diphenyl sulfone bismaleimide, 1,3-bis(3-maleimide phenoxy)benzene, 1,3-bis(4-maleimide phenoxy)benzene, Zylok-type maleimide compounds (ANILIX maleimide, MITSUI FINE) CHEMICALS, Inc.), biphenyl aralkyl maleimide compounds (cured by distilling off the solvent from a resin solution containing the maleimide compound (M2) described in Example 4 of Japanese Patent Application Publication No. 2009-001783 under reduced pressure), diaminoisopropylphenylbenzene maleimide (maleimide compound described in International Publication No. 2020 / 054601), maleimide compounds with an indane structure described in Japanese Patent No. 6629692 or International Publication No. 2020 / 217679, MATERIAL STAGE Vol. 18, No. 12 2019 "Continued from Epoxy Resin CAS Numbering Story to Hardener CAS Numbering Memorandum, No. 31, Bismaleimide (1)", or MATERIAL STAGE Vol. 19, No. 2 The maleimide compounds disclosed in 2019 "Continuation of the CAS Number Story of Epoxy Resins to CAS Number Memorandum of Hardeners, No. 32, Bismaleimide (2)" are not limited to these. In addition, one or more of these can be used.

[0145] The amount of maleimide compound other than that shown in formula (1) is preferably 10 times or less by mass, more preferably 5 times or less by mass, and particularly preferably 3 times or less by mass, relative to the maleimide compound shown in formula (1). Furthermore, the lower limit is preferably 0.01 times or more by mass, more preferably 0.1 times or more by mass. Within the above range, the heat resistance, dielectric properties, and low water absorption of the compound shown in formula (1) can be achieved.

[0146] [Compounds containing vinyl unsaturated bonds]

[0147] Compounds containing ethylene unsaturated bonds are compounds with one or more ethylene unsaturated bonds in their molecules that can be polymerized by heat or light, regardless of the use of a polymerization initiator.

[0148] Examples of compounds containing vinyl unsaturated bonds include, for instance, reactants of the aforementioned phenolic resins with halogen compounds containing vinyl unsaturated bonds (chloromethylstyrene, allyl chloride, methylallyl chloride, acryloyl chloride, methacryloyl chloride, etc.); reactants of phenols containing vinyl unsaturated bonds (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) with halogen compounds (1,4-bis(chloromethyl)benzene, 4,4'-bis(chloromethyl)biphenyl, 4,4'-difluorodiphenyl ketone, 4,4'-dichlorodiphenyl ketone, 4,4'-dibromodiphenyl ketone, cyanuric trichloroethylene, etc.); reactants of epoxy resins or alcohols with (meth)acrylic acids (acrylic acid, methacrylic acid, etc.); and acid-modified derivatives of these compounds, but are not limited to these examples. Furthermore, one or more of these compounds may be used in combination.

[0149] [Isocyanate resin]

[0150] Isocyanate resins refer to compounds having two or more isocyanate groups within their molecules. Examples of isocyanate resins include aromatic diisocyanates such as terephthalic diisocyanate, isophthalic diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and naphthalene diisocyanate; aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate, norcamphene diisocyanate, and lysine diisocyanate; biuret forms of one or more isocyanate monomers; polyisocyanates such as isocyanates formed by trimerization of the above diisocyanate compounds; and polyisocyanates obtained by ethyl carbamate esterification of the above isocyanate compounds with polyol compounds, but are not limited to these. In addition, these can be used in one or in combination.

[0151] [Polyamide resin]

[0152] Examples of polyamide resins include diamines, diisocyanates, etc. Reactions of any one or more azoline compounds with dicarboxylic acids, reactions of diamines with acyl chlorides, and ring-opening polymers of lactam compounds. Additionally, one or more of these may be used.

[0153] The following are specific examples of the above-mentioned raw materials, but are not limited to these.

[0154] <Diamine>

[0155] Ethylenediamine, Trimethylenediamine, Tetramethylenediamine, Pentamethylenediamine, Hexamethylenediamine, Heptamethylenediamine, Octamethylenediamine, Nonamethylenediamine, Decanediamine, Undecanediamine, Dodecanediamine, Tridecanediamine, Tetradecanediamine, Pentadecanediamine, Hexadecanediamine, Heptadecanediamine, Octadecanediamine, Nonadecanediamine, Eicosanediamine, 2-Methyl-1,5-Diaminopentane, 2-Methyl-1,8-Diaminooctane, Dimer Diamine, cyclohexanediamine, bis-(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, xylenediamine, norcamphenediamine, isophoronediamine, diaminomethyltricyclodecane, phenylenediamine, diethyltoluenediamine, naphthyldiamine, 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-ethylidene diphenylamine, diaminodiphenyl sulfone, diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-aminophenoxy) [4-(4-aminophenoxy)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, diaminodiphenyl ketone, etc.

[0156] Diisocyanate

[0157] Benzene diisocyanate, toluene diisocyanate, 1,3-bis(isocyanomethyl)benzene, 1,3-bis(isocyanomethyl)cyclohexane, bis(4-isocyanophenyl)methane, isophorone diisocyanate, 1,3-bis(2-isocyano-2-propyl)benzene, 2,2-bis(4-isocyanophenyl)hexafluoropropane, dicyclohexylmethane-4,4'-diisocyanate, etc.

[0158] Dicarboxylic acid

[0159] Oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanoic acid, terephthalic acid, isophthalic acid, 5-hydroxyisophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, sodium 5-sulfoisophthalate, hexahydroterephthalic acid, hexahydroisophthalic acid, cyclohexanedicarboxylic acid, biphenyl dicarboxylic acid, naphthalene dicarboxylic acid, diphenyl ketone dicarboxylic acid, furan dicarboxylic acid, 4,4'-dicarboxylic diphenyl ether, 4,4'-dicarboxylic diphenyl sulfide, etc.

[0160] Acyl chloride

[0161] Acetyl chloride, acryloyl chloride, methacryloyl chloride, malonyl chloride, succinyl dichloride, 2,2'-oxydiacetyl chloride, glutaryl dichloride, octanoyl dichloride, sebacyl dichloride, adipyl dichloride, dodecyl dichloride, azelaic chloride, 2,5-furandicarboxyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesoyl chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarboxyl chloride, 4,4'-azodibenzoyl chloride, etc.

[0162] <lactam>

[0163] ε-caprolactam, ω-undecanolactam, ω-laurolactam, etc.

[0164] [Polyimide resin]

[0165] Examples of polyimide resins include, but are not limited to, the reaction products of the aforementioned diamines and the tetracarboxylic dianhydrides exemplified below. Furthermore, one or more of these can be used.

[0166] Tetracarboxylic dianhydride

[0167] 4,4'-(hexafluoroisopropylidene) phthalic anhydride, 5-(2,5-di-sideoxytetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2-dicarboxylic anhydride, pyrolithic dianhydride, 1,2,3,4-benzenetetracarboxylic anhydride, 3,3',4,4'-diphenylketonetetracarboxylic anhydride, 2,2',3,3'-diphenylketonetetracarboxylic anhydride, 3,3',4,4'-biphenyltetracarboxylic anhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic anhydride, 2,2',3,3'-biphenyltetracarboxylic anhydride, methylene-4,4'-phthalic anhydride, 1,1-ethylidene-4,4'-phthalic anhydride, 2,2'-propylidene-4,4'-phthalic anhydride, 1,2-ethyleneidene 1,3-Trimethylene-4,4'-Diphthalic dianhydride, 1,4-Tetramethylene-4,4'-Diphthalic dianhydride, 1,5-Pentamethylene-4,4'-Diphthalic dianhydride, 4,4'-Oxybisphthalic dianhydride, Thio-4,4'-Diphthalic dianhydride, Sulfonyl-4,4'-Diphthalic dianhydride, 1,3-Bis(3,4-dicarboxyphenyl)phthalic dianhydride, 1,3-Bis(3,4-dicarboxyphenoxy)phthalic dianhydride, 1,4-Bis(3,4-dicarboxyphenoxy)phthalic dianhydride, 1,3-Bis[2-(3,4-dicarboxyphenyl)-2-propyl]phthalic dianhydride, 1,4-Bis[2-(3,4-dicarboxyphenyl)-2- [Propyl]phenyl dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 2,3,6,7-anthracitetetracarboxylic acid dianhydride, 1,2,7 8-Phenylacetetrate dianhydride, ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3,3',4,4'-biscyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 2,2-propylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid)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]oct-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-disideloxytetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, ethylene glycol-bis-(3,4-dicarboxylic anhydride phenyl) ether, 4,4'-biphenylbis(triphenyltriester anhydride), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dihydride, etc.

[0168] [Cyanate ester resin]

[0169] Cyanate ester resins are cyanate ester compounds obtained by reacting phenolic resins with cyanide halides. Specific examples include benzene dicyanate, benzene tricyanate, naphthalene dicyanate, biphenyl dicyanate, 2,2'-bis(4-cyanophenyl)propane, bis(4-cyanophenyl)methane, bis(3,5-dimethyl-4-cyanophenyl)methane, 2,2'-bis(3,5-dimethyl-4-cyanophenyl)propane, 2,2'-bis(4-cyanophenyl)ethane, 2,2'-bis(4-cyanophenyl)hexafluoropropane, bis(4-cyanophenyl)sulfone, bis(4-cyanophenyl) sulfide, phenolic varnish cyanate, and cyanate esters obtained by converting the hydroxyl groups of phenol / dicyclopentadiene cocondensates to cyanate ester groups, but are not limited to these. Furthermore, one or more of these can be used.

[0170] Furthermore, the cyanate ester compound synthesized by the method described in Japanese Patent Application Publication No. 2005-264154 has excellent low hygroscopicity, flame retardancy, and dielectric properties, and is therefore a preferred cyanate ester compound.

[0171] Cyanate ester resins can optionally trimerize cyanate ester groups to form sym-trimer. The catalyst may contain zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octanoate, tin octanoate, lead acetylacetone, dibutyltin maleate, etc.

[0172] The amount of catalyst used relative to 100 parts by weight of cyanate ester resin is 0.0001 to 0.10 parts by weight, more preferably 0.00015 to 0.0015 parts by weight.

[0173] [Polyphenylene ether compounds]

[0174] From the viewpoint of heat resistance and electrical properties, polyphenylene ether compounds are more preferably polyphenylene ether compounds with vinyl unsaturated bonds, and more preferably polyphenylene ether compounds with acryloyl, methacryl, or styrene structures. Commercially available examples include SA-9000 (a polyphenylene ether compound with methacryl groups manufactured by SABIC) and OPE-2St1200 (a polyphenylene ether compound with a styrene structure manufactured by Mitsubishi Gas Chemical Co., Ltd.).

[0175] The number average molecular weight (Mn) of the polyphenylene ether compound is preferably 500 to 5000, more preferably 2000 to 5000, and even more preferably 2000 to 4000. If the molecular weight is less than 500, there is a tendency to not obtain sufficient heat resistance of the cured product. In addition, if the molecular weight is greater than 5000, the melt viscosity will increase, and sufficient fluidity will not be obtained, so there is a tendency for poor molding. Furthermore, the reactivity will also decrease, the curing reaction will require a long time, and the number of unreacted substances that have not entered the curing system will increase, which will lower the glass transition temperature of the cured product and tend to reduce the heat resistance of the cured product.

[0176] Polyphenylene ether compounds with a number-average molecular weight of 500 to 5000 can exhibit excellent heat resistance and moldability while maintaining excellent dielectric properties. Furthermore, this number-average molecular weight can be specifically determined using methods such as colloidal permeation chromatography.

[0177] Polyphenylene ether compounds can be obtained through polymerization or by redistribution reactions of high molecular weight polyphenylene ether compounds with a number average molecular weight of approximately 10,000 to 30,000. Alternatively, these compounds can be used as raw materials and reacted with compounds containing vinyl unsaturated bonds, such as methacryloyl chloride, acryloyl chloride, and chloromethylstyrene, thereby imparting free radical polymerization properties. Polyphenylene ether compounds obtained through redistribution reactions can be obtained, for example, by heating high molecular weight polyphenylene ether compounds in a solvent such as toluene in the presence of a phenolic compound and a free radical initiator. As described above, polyphenylene ether compounds obtained through redistribution reactions have hydroxyl groups derived from phenolic compounds at both ends of the molecular chain that participate in curing, thus maintaining higher heat resistance. Furthermore, functional groups can be introduced at both ends of the molecular chain after modification with compounds containing vinyl unsaturated bonds, which is preferable. Additionally, polyphenylene ether compounds obtained through polymerization reactions exhibit excellent flowability, which is also preferable.

[0178] The molecular weight of polyphenylene ether compounds can be adjusted by adjusting polymerization conditions when the compound is obtained through polymerization. Conversely, when the compound is obtained through redistribution reactions, the molecular weight can be adjusted by adjusting the conditions of the redistribution reaction. More specifically, adjusting the amount of phenolic compounds used in the redistribution reaction is a consideration. That is, the higher the amount of phenolic compounds used, the lower the molecular weight of the resulting polyphenylene ether compound. In this case, high molecular weight polyphenylene ether compounds undergoing the redistribution reaction can be poly(2,6-dimethyl-1,4-phenylene ether), etc. Furthermore, there are no particular limitations on the phenolic compounds used in the aforementioned redistribution reaction; however, polyfunctional phenolic compounds with two or more phenolic hydroxyl groups, such as bisphenol A, phenolic varnish, and cresol varnish, are preferred. These can be used alone or in combination of two or more.

[0179] The content of the polyphenylene ether compound is not particularly limited, but it is more preferably 5 to 1000 parts by mass relative to 100 parts by mass of the compound shown in formula (1) above, and more preferably 10 to 750 parts by mass. If the content of the polyphenylene ether compound is within the above range, it not only has excellent heat resistance, but also a cured product that fully utilizes the excellent dielectric properties of the polyphenylene ether compound can be obtained, which is more preferred from this point of view.

[0180] Polybutadiene and its modified derivatives

[0181] Polybutadiene and its modified derivatives refer to polybutadiene or compounds with structures derived from polybutadiene within their molecules. These polybutadiene-derived structures can be converted, through hydrogenation, into single bonds, either partially or completely.

[0182] Examples of polybutadiene and its modified derivatives include, but are not limited to, polybutadiene, hydroxyl-terminated polybutadiene, terminal (meth)acrylated polybutadiene, carboxylic acid-terminated polybutadiene, amine-terminated polybutadiene, and styrene-butadiene rubber. Furthermore, one or more of these can be used. From the viewpoint of dielectric properties, polybutadiene or styrene-butadiene rubber is preferred. Examples of styrene-butadiene rubber (SBR) include RICON-100, RICON-181, RICON-184 (all manufactured by CRAY VALLEY), and 1,2-SBS (manufactured by Nippon Soda), while examples of polybutadiene include B-1000, B-2000, and B-3000 (all manufactured by Nippon Soda). The molecular weight of both polybutadiene and styrene-butadiene rubber is preferably 500 to 10,000 by weight average, more preferably 750 to 7,500, and even more preferably 1,000 to 5,000. Below the lower limit of the above range, the amount of volatiles is relatively high, making it difficult to adjust the solids content when making the prepreg. Above the upper limit of the above range, the compatibility with other curing resins deteriorates. Generally speaking, when it is a compound containing heteroatoms such as bismaleimide or polymaleimide, its polarity makes it difficult to guarantee compatibility with low-polarity compounds such as compounds mainly composed of hydrocarbons or compounds composed only of hydrocarbons. On the other hand, the compound shown in the above formula (1) is not designed with a skeleton that actively incorporates heteroatoms such as oxygen or nitrogen, so its compatibility with low-polarity materials with low dielectric properties or compounds composed only of hydrocarbons is also excellent.

[0183] The content of polybutadiene and its modifiers is not particularly limited, but is preferably 5 to 1000 parts by mass relative to 100 parts by mass of the compound shown in formula (1), and more preferably 10 to 750 parts by mass. If the content of polybutadiene and its modifiers is within the above range, it not only has excellent heat resistance, but also yields a cured product that fully utilizes the excellent dielectric properties of polybutadiene and its modifiers, which is preferred from this point of view.

[0184] Polystyrene and its modified forms

[0185] Polystyrene and its modified products refer to polystyrene or compounds with structures derived from polystyrene within their molecules.

[0186] Examples of polystyrene and its modified derivatives include polystyrene, styrene·2-isopropenyl-2- Azoline copolymers (Epocros RPS-1005, RP-61, both manufactured by Nippon Catalyst Co., Ltd.), SEP (styrene-ethylene-propylene copolymer: Septon 1020, manufactured by Kurara), SEPS (styrene-ethylene-propylene-styrene copolymer: Septon 2002, Septon 2004F, Septon 2005, Septon 2006, Septon 2063, Septon 2104, all manufactured by Kurara), SEEPS (styrene-ethylene / ethylene-propylene-styrene block copolymer: Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099, all manufactured by Kurara), SEBS (styrene-ethylene-butene / styrene block copolymer: Septon 8004, Septon 8006, Septon... The following are examples of styrene products, but not limited to these: 8007L (all manufactured by Kuraray), SEEPS-ОH (a compound with hydroxyl groups at the end of a styrene-ethylene / ethylene·propylene / styrene block copolymer: Septon HG252, manufactured by Kuraray), SIS (styrene-isoprene-styrene block copolymers: Septon 5125, Septon 5127, both manufactured by Kuraray), hydrogenated SIS (hydrogenated styrene / isoprene / styrene block copolymers: hybrar7125F, hybrar 7311F, both manufactured by Kuraray), SIBS (styrene-isobutylene-styrene block copolymers: SIBSTAR073T, SIBSTAR102T, SIBSTAR103T (all manufactured by Kaneka), Septon V9827 (manufactured by Kuraray)). Furthermore, one or more of these products may be used. To ensure high heat resistance and resistance to oxidation and degradation, polystyrene and its modified forms are preferably free of unsaturated bonds. Furthermore, there are no particular restrictions on the weight-average molecular weight of polystyrene and its modified forms exceeding 10,000. However, if the weight-average molecular weight is too high, the compatibility with low molecular weight components (around 50 to 1000) and oligomer components (around 1000 to 5000) will deteriorate, making it difficult to ensure mixing and solvent stability. Therefore, a weight-average molecular weight of around 10,000 to 300,000 is preferred.

[0187] The content of polystyrene and its modifiers is not particularly limited, but is preferably 5 to 1000 parts by mass relative to 100 parts by mass of the compound shown in formula (1), and more preferably 10 to 750 parts by mass. If the content of styrene and its modifiers is within the above range, it not only has excellent heat resistance, but also yields a cured product that fully utilizes the excellent dielectric properties of polystyrene and its modifiers, and is therefore preferred.

[0188] The curable resin composition of this embodiment can be obtained by mixing the above-mentioned components in a specific ratio, pre-curing at 130 to 180°C for 30 to 500 seconds, and then further curing at 150 to 200°C for 2 to 15 hours to fully carry out the curing reaction and obtain the cured product of this embodiment. Alternatively, post-curing can be performed by uniformly dispersing or dissolving the components of the curable resin composition in a solvent or the like and then removing the solvent.

[0189] The method for preparing the curable resin composition of this embodiment is not particularly limited; the components may be simply mixed uniformly or prepolymerized. For example, a mixture of maleimide compound and other compounds as shown in formula (1) may be prepolymerized by heating in the presence or absence of a curing accelerator or polymerization initiator, or in the presence or absence of a solvent. Similarly, amine compounds, compounds having ethylene unsaturated bonds, maleimide compounds other than those shown in formula (1), cyanate compounds, polybutadiene and its modified forms, polystyrene and its modified forms, inorganic fillers, and other additives may be added and prepolymerized. The mixing or prepolymerization of the components may be carried out in the absence of a solvent, for example using an extruder, kneader, roller, etc., or in the presence of a solvent using a reactor with a stirring device, etc.

[0190] As a homogeneous mixing method, a kneading method can be used within a temperature range of 50 to 100°C to form a homogeneous resin composition. The resulting resin composition can be pulverized and molded into cylindrical tablets, granular powder, or powder-based molded articles using a molding machine such as a pressing machine. Alternatively, these compositions can be melted onto a surface support and molded into sheets with a thickness of 0.05 mm to 10 mm to form a cured resin composition molded article. The resulting molded article is non-sticky at 0 to 20°C, and its fluidity and curability are almost unaffected even after storage at -25 to 0°C for more than one week.

[0191] The resulting molded body can be transferred to a molding machine or a compression molding machine to be molded into a hardened material.

[0192] The curable resin composition of this embodiment can also be supplemented with an organic solvent to form a varnish-like composition (hereinafter simply referred to as varnish). The curable resin composition of this embodiment is optionally dissolved in solvents such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone to form a varnish. This varnish is then impregnated into a substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, or paper and dried by heating. The resulting prepreg is then hot-pressed to form a cured product of the curable resin composition of this embodiment. The solvent used in this process is preferably in an amount of 10 to 70% by weight, more preferably 15 to 70% by weight, in the mixture of the curable resin composition and the solvent of this embodiment. Alternatively, if it is a liquid composition, a cured product containing carbon fibers can be obtained directly, for example, by RTM (Resin Transfer Molding).

[0193] Alternatively, the curing composition of this embodiment can also be used as a modifier for film-type compositions. Specifically, it can be used to improve flexibility in the B stage, etc. The film-type resin composition is prepared by coating the curing resin composition of this embodiment onto a release film as a varnish of the aforementioned curing resin composition, removing the solvent under heat, and then performing B-stage curing to obtain a sheet-like adhesive. This sheet-like adhesive can be used as an interlayer insulating layer in multilayer substrates, etc.

[0194] The curable resin composition of this embodiment can also be obtained by heating and melting, reducing viscosity, and impregnating it in reinforcing fibers such as glass fibers, carbon fibers, polyester fibers, polyamide fibers, and alumina fibers to obtain a prepreg. Specific examples include 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 fibers of inorganic materials other than glass, or poly(p-phenylene terephthalamide) (Kevlar (registered trademark), manufactured by DuPont), fully aromatic polyamides, polyesters, and poly(p-phenylene terephthalamide)... Organic fibers such as azole, polyimide, and carbon fiber are used, but are not limited to these. The shape of the substrate is not particularly limited, and examples include woven fabric, nonwoven fabric, roving, and diced felt. Furthermore, the weaving methods are known, including plain weave, square plain weave, and twill weave, which can be appropriately selected and used by those skilled in the art according to the intended use or performance. Additionally, glass fabrics that have undergone defiberization or surface treatment with silane coupling agents are suitable. The thickness of the substrate is not particularly limited, but is preferably around 0.01 to 0.4 mm. Furthermore, the aforementioned varnish can be impregnated with reinforcing fibers and heated and dried to obtain a prepreg.

[0195] Alternatively, the aforementioned prepregs can be used to manufacture laminates. There are no particular limitations on the laminate as long as it has one or more prepregs; it can have any other layers. The manufacturing method of the laminate can appropriately use generally known methods and is not particularly limited. For example, in the molding of a metal foil-coated laminate, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, an autoclave molding machine, etc., can be used to stack the aforementioned prepregs together and heat and pressurize them to obtain the laminate. In this case, the heating temperature is not particularly limited, but 65 to 300°C is preferred, and 120 to 270°C is more preferred. Furthermore, the pressure applied is not particularly limited. If the pressure is too high, it will be difficult to adjust the solids content of the resin in the laminate, resulting in unstable quality. Conversely, if the pressure is too low, air bubbles or poor adhesion between layers will occur. Therefore, 2.0 to 5.0 MPa is preferred, and 2.5 to 4.0 MPa is more preferred. The laminate of this embodiment has a layer made of metal foil, and is therefore suitable for use as a metal foil-clad laminate as described later.

[0196] The prepreg is cut into the desired shape and optionally laminated with copper foil, etc. Pressure is applied to the laminate by compression molding, autoclave molding, sheet winding molding, etc., while the curable resin composition is heated and cured, thereby obtaining an electrical and electronic laminate (printed circuit board) or carbon fiber reinforced material.

[0197] The curable resin composition of this embodiment can also be formed into a resin sheet. As a method for obtaining a resin sheet from the curable resin composition of this embodiment, a method can be exemplified by coating the curable resin composition onto a support film (support) and then drying it to form a resin composition layer on the support film. When using the curable resin composition of this embodiment for a resin sheet, it is important that the film softens under the lamination temperature conditions (70°C to 140°C) in a vacuum lamination process and exhibits fluidity (resin flow) that allows the resin to fill through-holes or vias present in the circuit board, simultaneously with the lamination of the circuit board. It is preferable to incorporate the aforementioned components in a manner that exhibits this characteristic. Furthermore, in order to prevent the occurrence of localized inconsistent characteristic values ​​due to phase separation or other issues in the resulting resin sheet or circuit board (copper foil laminate, etc.) and to ensure consistent fixation performance at any location, uniform appearance is required.

[0198] Here, the diameter of the through-hole in the circuit board is 0.1 to 0.5 mm, and the depth is 0.1 to 1.2 mm, preferably within this range for resin filling. Furthermore, when laminating both sides of the circuit board, it is preferable to fill approximately half of the through-hole.

[0199] A specific method for manufacturing the aforementioned resin sheet is to mix an organic solvent and prepare a varnished resin composition, then coat the varnished resin composition onto the surface of a support film (Y), and further dry the organic solvent by heating or blowing hot air to form a resin composition layer (X).

[0200] The organic solvents used herein are preferably ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetates such as ethyl acetate, butyl acetate, ceroxox acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as ceroxox and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide; dimethylacetamide; and N-methylpyrrolidone. Furthermore, it is preferred that the solvents be used at a ratio of 30 to 60% by mass of non-volatile components.

[0201] Furthermore, the thickness of the aforementioned resin composition layer (X) needs to be greater than or equal to the thickness of the conductor layer. Since the thickness of the conductor layer in the circuit board is in the range of 5 to 70 μm, the thickness of the aforementioned resin composition layer (X) is preferably 10 to 100 μm. Additionally, the aforementioned resin composition layer (X) in this embodiment can be protected by a protective film, as described later. Protecting the surface of the resin composition layer with a protective film prevents the adhesion of dirt or scratches.

[0202] Examples of the aforementioned support film and protective film include polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate; polycarbonate; polyimide; and release paper or metal foils such as copper foil and aluminum foil. In addition to matte treatment and corona treatment, the support film and protective film can also undergo release treatment. The thickness of the support film is not particularly limited, and is preferably in the range of 10 to 150 μm, or more preferably 25 to 50 μm. The thickness of the protective film is preferably 1 to 40 μm.

[0203] The aforementioned support film (Y) is peeled off after being laminated onto the circuit board or after forming an insulating layer through heat curing. If the support film (Y) is peeled off after the resin composition layer constituting the resin sheet has been heat-cured, the adhesion of contaminants or other substances from the curing process can be prevented. During peeling after curing, the support film undergoes a pre-molding treatment.

[0204] Alternatively, a multilayer printed circuit board can be manufactured from the resin sheet obtained in the aforementioned manner. For example, when the aforementioned resin composition layer (X) is protected with a protective film, after these are peeled off, the resin composition layer (X) is directly bonded to the circuit board, and laminated on one or both sides of the circuit board, for example, by a vacuum lamination method. The lamination method can be batch lamination or continuous roller lamination. Optionally, the resin sheet and the circuit board can be heated (preheated) before lamination. The lamination conditions are preferably a pressing temperature (lamination temperature) of 70 to 140°C and a pressing pressure of 1 to 11 kgf / cm². 2 (9.8×10⁴ to 107.9×10⁴) 4 N / m 2 It is more preferably laminated under reduced pressure at an air pressure of 20 mmHg (26.7 hPa) or below.

[0205] 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 Scale Package), SOP (Small Outline Package), TSOP (Thin Small Outline Package), and TQFP (Thin Quad Flat Package).

[0206] The curable resin composition and its cured product of 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 coatings. The cured product of the curable resin composition described in this embodiment exhibits excellent heat resistance and dielectric properties, and is therefore suitable for use in electrical and electronic components such as sealing materials for semiconductor components, sealing materials for liquid crystal display components, sealing materials for organic EL components, laminates (printed circuit boards, BGA substrates, add-on substrates, etc.), or composite materials such as lightweight, high-strength structural materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, as well as 3D printing.

[0207] (Example)

[0208] The present invention will then be further described in detail through examples. Hereinafter, unless otherwise specified, parts refer to parts by weight. Furthermore, the present invention is not limited to these examples.

[0209] The following describes the various analytical methods used in the examples.

[0210] GPC (Colloidal Permeation Chromatography) Analysis

[0211] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) are calculated using a polystyrene standard solution and by conversion to polystyrene.

[0212] GPC: Online degassing unit (DGU-20A3R), binary liquid delivery unit (LC-20AD), autosampler (SIL-20AHT), differential refractive index detector (RID-20A), column oven (CTO-20A), system controller (CBM-20A) (all manufactured by Shimadzu Corporation)

[0213] Tube Columns: Shodex KF-603×1, KF-602.5×1, KF-602×1, KF-601×1 (all manufactured by Showa Denko Corporation)

[0214] Protective tubing string: Shodex KF-G 4A (manufactured by Showa Denko Corporation)

[0215] Connecting solution: tetrahydrofuran

[0216] Flow rate: 1.5 ml / min.

[0217] Column temperature: 40℃

[0218] Detection: RI (Differential Refraction Detector)

[0219] · 1 H-NMR analysis

[0220] Apparatus: Nuclear Magnetic Resonance Imaging System (JNM-ECS400), manufactured by Japan Electronics Corporation.

[0221] [Example 1]

[0222] In a flask equipped with a thermometer, cooling pipe, stirrer, and Dean-Stark apparatus, 24.3 parts of 2,6-dimethylaniline, 136 parts of α,α,α',α'-tetramethyl-1,3-benzenedimethanol, 100 parts of toluene, and 35 parts of activated clay were added. The mixture was reacted at an internal temperature of 110-135°C for 1.5 hours while removing the generated water using azeotropic dehydration. Subsequently, while removing the toluene, the internal temperature was raised to 210°C and the reaction was continued for 4 hours. After cooling, the removed toluene was returned to the system, and 200 parts of new toluene were added. The activated clay was removed by filtration, yielding a toluene solution (T-1) containing the amine compound shown in formula (6). The GPC chart of the obtained amine compound is shown in [reference needed]. Figure 1 .

[0223] Next, 100 parts of toluene, 29.4 parts of maleic anhydride, and 5.4 parts of methanesulfonic acid were added to a flask equipped with a thermometer, cooling pipe, stirrer, and Dean-Stark apparatus. T-1 was added dropwise over 4 hours while maintaining the internal temperature at 110°C. Further polymerization of the olefin portion of the amine shown in formula (6) and maleimidation of the amino group were carried out at 110°C for 9 hours. After cooling, 200 parts of toluene were added, and the organic layer was washed 5 times with 100 parts of water. The solvent was removed by distillation under reduced pressure, thereby obtaining 133 parts of a brown solid resin, maleimide compound (M-1) shown in formula (7). The GPC chart of the obtained maleimide compound is shown in [reference needed]. Figure 2 The number-average molecular weight (Mn) was 2082, and the weight-average molecular weight (Mw) was 3169. Furthermore, the obtained maleimide compound... 1 H-NMR charts (deuterated chloroform) are presented in Figure 3 . 1 A signal originating from maleimide groups was observed at 6.85 ppm in the H-NMR chart.

[0224]

[0225] [Example 2]

[0226] 35.4 parts of 2,6-diisopropylaniline, 136 parts of α,α,α',α'-tetramethyl-1,3-benzenedimethanol, 100 parts of toluene, and 35 parts of activated clay were added to a flask equipped with a thermometer, cooling pipe, stirrer, and Dean-Stark apparatus. The mixture was reacted at an internal temperature of 110-135°C for 2 hours while removing the generated water using azeotropic dehydration. Subsequently, the internal temperature was raised to 210°C and the reaction was continued for 9 hours while removing the toluene. After cooling, the removed toluene was returned to the system, and 200 parts of new toluene were added. The activated clay was removed by filtration, yielding a toluene solution (T-2) containing the amine compound shown in formula (8). The GPC chart of the obtained amine compound is shown in... Figure 1 .

[0227] Next, 100 parts of toluene, 29.4 parts of maleic anhydride, and 5.4 parts of methanesulfonic acid were added to a flask equipped with a thermometer, cooling pipe, stirrer, and Dean-Stark apparatus. T-2 was added dropwise over 2 hours while maintaining the internal temperature at 110°C. Further polymerization of the olefin portion of the amine shown in formula (8) and maleimidation of the amino group were carried out at 110°C for 10 hours. After cooling, 200 parts of toluene were added, and the organic layer was washed 5 times with 100 parts of water. The solvent was removed by distillation under heating and reduced pressure, thereby obtaining 125 parts of a brown solid resin, maleimide compound (M-2) shown in formula (9). The GPC chart of the obtained maleimide compound is shown in [reference needed]. Figure 5The number-average molecular weight (Mn) was 2007, and the weight-average molecular weight (Mw) was 3301. Furthermore, the obtained maleimide compound... 1 H-NMR charts (deuterated chloroform) are presented in Figure 6 . 1 A signal originating from maleimide groups was observed at 6.85 ppm in the H-NMR chart.

[0228]

[0229] [Synthesis example 1]

[0230] In a flask equipped with a thermometer, cooling pipe, stirrer, and Dean-Stark apparatus, 48.5 parts of 2,6-dimethylaniline, 155.4 parts of α,α,α',α'-tetramethyl-1,3-benzenedimethanol, 100 parts of toluene, and 30.6 parts of activated clay were added. While removing toluene and the generated water using azeotropic dehydration, the internal temperature was raised to 210°C over 2 hours, and the reaction was carried out for 3 hours (GPC chart shown). Figure 7 After cooling the internal temperature to 120°C, 145.4 parts of 2,6-dimethylaniline were added and reacted at 220°C for 3 hours. After cooling, the extracted toluene was returned to the system, and 200 parts of new toluene were added. The activated clay was removed by filtration, and the solvent and excess 2,6-dimethylaniline were distilled off, thereby obtaining 207 parts (amine equivalent: 272.7 g / eq.) of the amine compound (A-1) of the following formula (10) in brown solid form. The GPC chart of the obtained amine compound is shown in Figure 7 The number-average molecular weight (Mn) is 1048, and the weight-average molecular weight (Mw) is 1252.

[0231]

[0232] [Synthesis example 2]

[0233] 50 parts toluene, 53.9 parts maleic anhydride, and 2 parts methanesulfonic acid were added to a flask equipped with a thermometer, cooling pipe, stirrer, and Dean-Stark apparatus. While maintaining reflux, a toluene and N-methylpyrrolidone (NMP) solution (A-1: 100 parts, toluene: 75 parts, NMP: 25 parts) was added dropwise over 1 hour. The maleimide reaction of the amino group was carried out under reflux for 2 hours. After cooling, 100 parts toluene were added, and the organic layer was washed 5 times with 100 parts water. The solvent was removed by distillation under reduced pressure, thereby obtaining 117 parts of a maleimide compound (M-3) of the following formula (11) in a brown solid resin. The GPC chart of the obtained maleimide compound is shown in [reference needed]. Figure 8 The number-average molecular weight (Mn) is 1353, and the weight-average molecular weight (Mw) is 1562.

[0234]

[0235] [Examples 3 to 6, Comparative Example 1]

[0236] The maleimide compounds (M-1, M-2, M-3) obtained in Examples 1 and 2 and Synthesis Example 2, and the thermal free radical polymerization initiator DCP (diisopropylbenzene peroxide, manufactured by Tokyo Chemical Co., Ltd.) were mixed at the ratios shown in Tables 1 and 2, respectively. The mixtures were then vacuum-pressed while being sandwiched between mirror copper foil (T4X: manufactured by Fukuda Metal Copper Foil Co., Ltd.), and cured at 220°C for 2 hours. During this process, a 150mm diameter and 150mm diameter section was cut from the center of a 250μm thick buffer paper to serve as a spacer. For evaluation, a laser cutter was optionally used to cut the test pieces to the desired dimensions and then the evaluation was performed. The evaluation results are presented in Tables 1 and 2.

[0237] <Dielectric coefficient test, loss tangent test>

[0238] The experiment was conducted using a 10GHz cavity resonator manufactured by AET Corporation, employing the cavity resonator perturbation method. The sample dimensions were 1.7mm wide × 100mm long and 0.3mm thick.

[0239] [Table 1]

[0240]

[0241] <Heat Resistance: Differential Scanning Calorimetry (DSC)>

[0242] The glass transition point Tg of the samples in Examples 5 and 6 was determined using a differential scanning calorimeter.

[0243] Differential scanning calorimeter: DSC6220 (manufactured by SII NanoTechnology)

[0244] Measurement temperature range: 30 to 330℃

[0245] Heating rate: 10℃ / minute

[0246] Environment: Nitrogen (30 mL / min)

[0247] Sample size: 5mg

[0248] Tg: The inflection point of the DSC chart is taken as Tg.

[0249] [Table 2]

[0250]

[0251] The results in Tables 1 and 2 confirm that the curable resin composition of the present invention has excellent dielectric properties and heat resistance.

[0252] This application claims priority based on Japanese Special Application No. 2022-052578 filed on March 28, 2022.

[0253] (Industrial utilization)

[0254] The curable resin composition containing maleimide compounds of the present invention and the cured product obtained by curing therefrom are suitable for use in electrical and electronic components such as semiconductor sealing materials, printed circuit boards, and laminates.

Claims

1. A maleimide compound represented by formula (1) below, In equation (1), there are multiple Rs that exist independently and represent hydrocarbon groups or haloalkyl groups with 1 to 10 carbon atoms, X is shown in equation (2) below, m is an integer from 0 to 4, n is the average of the number of repetitions, and 1 ≤ n ≤ 20; In equation (2), there are multiple Rs that exist independently and represent hydrocarbon groups or haloalkyl groups with 1 to 10 carbon atoms, p represents an integer from 0 to 4, q represents an integer from 0 to 3, r is the average of the number of repetitions and is 1≤r≤20, and * represents the bonding position with the aromatic ring of the aforementioned equation (1).

2. A maleimide compound represented by formula (3) below, In equation (3), X is as shown in equation (4) below, and n is the average number of repetitions and is 1.1≤n≤20; In equation (4), multiple Rs exist independently and represent hydrocarbon groups with 1 to 5 carbon atoms, p represents an integer from 0 to 4, and r is the average of the number of repetitions, and 1.1 ≤ r ave ≤20, * indicates the bonding position of the aromatic ring of the compound with formula (3).

3. The maleimide compound according to claim 2, wherein, In the aforementioned formula (4), p is 2, and the substitution position of R is ortho relative to the maleimide group.

4. A curable resin composition comprising the maleimide compound according to any one of claims 1 to 3.

5. The curable resin composition according to claim 4 further comprises a free radical polymerization initiator.

6. A cured material obtained by curing the curable resin composition according to claim 4 or 5.

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