Curable resin composition and its cured product

Abstract

The objective is to provide a curable resin composition and a cured product thereof that exhibit excellent low dielectric properties. [Solution] A curable resin composition containing a maleimide resin having a maleimide equivalent of 150 g / eq. to 1200 g / eq. and having at least one maleimide group in its molecule, a cyanate ester resin, and a curable resin represented by the following formula (1). TIFF2026142516000028.tif44170 (In equation (1), the multiple R1 and R2 entities exist independently of each other. R1 represents a hydrocarbon group with 1 to 50 carbon atoms, and R2 represents a hydrocarbon group with 1 to 10 carbon atoms. l and m represent integers from 0 to 4.)

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition and its cured product, and is suitably used in electrical and electronic components such as semiconductor encapsulants, printed circuit boards, build-up laminates, and optical waveguide devices, as well as redistribution layers, lightweight 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 required characteristics of laminates used to mount electrical and electronic components have become broader and more sophisticated due to the expansion of their application fields. While conventional semiconductor chips were mainly mounted on metal lead frames, high-performance semiconductor chips such as central processing units (hereinafter referred to as CPUs) are increasingly being mounted on laminates made of polymer materials.

[0003] The fifth-generation communication system, "5G," aims for even greater capacity and higher speed communication. While 5G will utilize higher frequencies, reducing transmission loss is crucial for achieving high-speed communication using high frequencies, requiring substrate materials with even lower dielectric properties. Transmission loss on printed circuit boards stems from both conductor loss and dielectric loss. As described in Non-Patent Literature 1, conductor loss is proportional to the square root of the dielectric constant and the dielectric loss tangent. Therefore, improving the dielectric loss tangent, which contributes more significantly than the dielectric constant, is effective in reducing transmission loss. Materials with low dielectric loss tangent include thermoplastic materials such as PTFE (polytetrafluoroethylene), LCP (liquid crystal polymer), and rubber materials, but they have poor moldability compared to thermosetting resins. Furthermore, rubber materials have low heat resistance, and when used in substrates, defects may occur during high-temperature mounting processes such as solder reflow testing, potentially compromising product reliability. Therefore, the development of thermosetting resins or compositions containing thermosetting resins with excellent low dielectric properties is desired.

[0004] Against this background, polymer materials excellent in low dielectric properties have been studied. For example, Patent Document 1 proposes a thermosetting resin composition containing an imide compound having a maleimide group and a phenol aralkyl resin having an aliphatic unsaturated bond. However, since phenolic hydroxyl groups that do not participate in the reaction remain during the curing reaction, the electrical properties cannot be said to be sufficient. Patent Document 2 discloses an allyl ether-modified biphenyl aralkyl novolak resin obtained by adding an allyl group together with a phenolic hydroxyl group. However, it has been shown that Claisen rearrangement occurs in allyl ether-modified biphenyl aralkyl novolak resins at 190°C, and at 200°C, which is a common molding temperature for substrates, phenolic hydroxyl groups that do not contribute to the curing reaction are generated, so that satisfactory electrical properties cannot be obtained. Patent Document 3 proposes a composition comprising a monofunctional maleimide compound and an olefin-containing polymer for the purpose of providing a resin composition that gives a cured product with low dielectric properties and high heat resistance, but the electrical properties thereof cannot be said to be sufficient. [Prior Art Document] [Non-Patent Literature]

[0005] [Non-Patent Literature 1] Factors of Signal Loss in High-speed Signal Transmission on Printed Circuit Boards (Mitsui Mining & Smelting Co., Ltd.) 29th Spring Conference of the Japan Institute of Electronics Packaging, 16P1-17 [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 04-359911 [Patent Document 2] International Publication No. 2016 / 002704 [Patent Document 3] Japanese Patent No. 7190649 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] The present invention has been made in view of such circumstances, and an object of the present invention is to provide a curable resin composition excellent in low dielectric properties and a cured product thereof. [Means for Solving the Problems]

[0008] That is, the present invention relates to a curable resin composition containing a maleimide resin having a maleimide equivalent of 150 g / eq. to 1200 g / eq. and having at least one maleimide group in the molecule, a cyanate ester resin, and a curable resin represented by the following formula (1).

[0009] [Chemical Formula]

[0010] (In formula (1), a plurality of R1, R2, l, and m each exist independently; R1 represents a hydrocarbon group having 1 to 50 carbon atoms; R2 represents a hydrocarbon group having 1 to 10 carbon atoms; l and m each represent an integer of 0 to 4.)

[0011] In the present application, "(value 1) to (value 2)" indicates that the upper and lower limit values are included. [Effects of the Invention]

[0012] According to the present invention, a curable resin composition excellent in low dielectric properties and a cured product thereof can be provided. [Brief Description of Drawings]

[0013] [Figure 1] Fig. 1 shows the HP-LC chart of Synthesis Example 1. [Mode for Carrying Out the Invention]

[0014] Hereinafter, an embodiment according to the present invention (hereinafter also referred to as "the present embodiment") will be described in more detail.

[0015] The curable resin composition of this embodiment contains a maleimide resin having a maleimide equivalent of 150 g / eq. to 1200 g / eq. and having at least one maleimide group in its molecule (hereinafter also referred to as the maleimide resin of this embodiment), a cyanate ester resin, and a curable resin represented by the following formula (1).

[0016] [ka]

[0017] In equation (1), the multiple R1, R2, l, and m each exist independently. R1 represents a hydrocarbon group with 1 to 50 carbon atoms. R2 represents a hydrocarbon group with 1 to 10 carbon atoms. l and m represent integers from 0 to 4.

[0018] The maleimide resin of this embodiment is not particularly limited as long as it has at least one maleimide group in its molecule and a maleimide equivalent of 150 g / eq. to 1200 g / eq., however, it is preferable that the maleimide resin is an aromatic maleimide resin in which the maleimide group is directly bonded to an aromatic ring. Here, the maleimide equivalent is the mass of a compound containing one equivalent of a maleimide group. For example, if a maleimide resin with a molecular weight of 150 has one maleimide group attached, the functional group equivalent will be 150 g / eq. The maleimide equivalent can be measured, for example, by the measurement method described in Japanese Patent Application Publication No. 2020-187012. Alternatively, if the maleimide equivalent can be calculated from the structural formula and the number of functional groups, that value may be used. It is preferable that the maleimide resin has two or more maleimide groups in its molecule, and it is particularly preferable that it is a maleimide resin represented by the following formula (2) or a maleimide resin represented by the following formula (3). These may be used individually or in combination.

[0019] [ka]

[0020] In the above formulas (2) and (3), a plurality of X, R3, and p are each independently present, X represents a hydrocarbon group having 1 to 25 carbon atoms, and preferably represents any one of the structures represented by the following formulas (1-a) to (1-f). R1 represents an alkyl group having 1 to 20 carbon atoms, or an aromatic group having 1 to 20 carbon atoms which may have a substituent. The alkyl group preferably has 1 to 5 carbon atoms, and more preferably is a methyl group. p is an integer of 0 to 4. n is the number of repetitions, each independently represents an integer of 1 to 20, n ave is the average value of n, 1<n ave <10 is preferable, 1<n ave <7 is more preferable, 1<n ave <5 is particularly preferable. Formula (3) has structural units of (a) and (b), wherein (a) and (b) are each bonded via *, and the repetition positions may be random. k and o are the numbers of repetitions, each independently represents an integer of 1 to 2000, k ave is the average value of k, k ave usually satisfies 1≦k ave ≦1000, preferably 2≦k ave ≦750, more preferably 3≦k ave ≦500. o ave is the average value of o, o ave usually satisfies 1≦o ave ≦1000, preferably 1≦o ave ≦500, more preferably 1.1≦o ave ≦100, and particularly preferably 1.1≦o ave ≦20. Since the values of k and o are derived from the raw material styrene-maleic acid copolymer, they can be obtained from the acid value thereof. As a preferred range of the molecular weight (weight average molecular weight (Mw) determined by gel permeation chromatography (GPC) measurement) of the raw material styrene-maleic acid copolymer, it is preferably 200 or more and less than 50000, more preferably 300 or more and less than 30000, and particularly preferably 400 or more and less than 20000. When the weight average molecular weight is less than 20000, purification by water washing becomes easy, and when it is 200 or more, the target compound does not volatilize in the solvent distillation step.

[0021] [ka]

[0022] In formulas (1-a) to (1-f), the multiple R4, R5, q, and t each exist independently. R4 represents an alkyl group having 1 to 20 carbon atoms, or an aromatic group having 1 to 20 carbon atoms that may have substituents. R5 represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aromatic group having 1 to 20 carbon atoms that may have substituents. The alkyl group is preferably one with 1 to 5 carbon atoms, and more preferably a methyl group. q is an integer from 0 to 4, and t is an integer from 0 to 3. r is the repeating number, representing an integer from 1 to 20. ave This is the mean value of r, and 1 <r ave <10 is preferred, 1 <r ave <7 is even more preferable, 1 <r ave <5 is particularly preferable.

[0023] In equation (2) above, the value of n can be calculated from the number-average molecular weight obtained by gel permeation chromatography (GPC, detector: RI) of the maleimide resin, or from the area ratio of each separated peak. In equation (3) above, if n=1, the solubility in the solvent is low, and if n is 10 or more, the flowability during molding is poor, and the properties of the cured product cannot be fully exhibited.

[0024] The maleimide equivalent of the maleimide resin in this embodiment is preferably 150 g / eq. or more as a lower limit, more preferably 200 g / eq. or more, even more preferably 250 g / eq. or more, and particularly preferably 300 g / eq. or more. The upper limit is preferably 1200 g / eq. or less, more preferably 1000 g / eq. or less, even more preferably 900 g / eq. or less, even more preferably 800 g / eq. or less, even more preferably 700 g / eq. or less, even more preferably 600 g / eq. or less, and particularly preferably 500 g / eq. or less. If the maleimide equivalent is less than 150 g / eq., the polarity increases, the compatibility with compound (1) deteriorates, and it becomes impossible to obtain a cured product, or if a cured product is obtained, it becomes brittle. On the other hand, if the maleimide equivalent is greater than 1200 g / eq., the heat resistance may deteriorate. When the maleimide equivalent is within the above range, a cured product can be obtained without degrading the heat resistance of the obtained cured product.

[0025] The softening point of the maleimide resin in this embodiment is preferably 50°C to 200°C, more preferably 60°C to 195°C, even more preferably 70°C to 190°C, and particularly preferably 80°C to 185°C. The melt viscosity at 150°C is 0.05 to 100 Pa·s, preferably 0.1 to 40 Pa·s.

[0026] The following describes a method for producing maleimide resin represented by formula (2) above, but is not limited to this method.

[0027] The maleimide resin represented by formula (2) above can use an aromatic amine resin as a precursor. For example, when X in formula (2) is (1-c) and R5 is hydrogen, formula (4) below is the precursor aromatic amine resin, and when X in formula (2) is (1-b) and R5 is a methyl group, formula (5) below is the precursor aromatic amine resin.

[0028] [ka]

[0029] In equations (4) and (5) above, R3, R4, p, q, and n have the same meaning as in equation (2) above.

[0030] There are no particular limitations on the method for obtaining the aromatic amine resin represented by formula (4) above. For example, Japanese Patent Publication No. 3-100016 and Japanese Patent Publication No. 8-16151 describe the reaction of anilines with dihalogenomethyl compounds or dialkoxymethyl compounds. By employing a similar method, the aromatic amine resin represented by formula (4) above can be obtained by reacting aniline with bishalogenomethyl biphenyls or bisalkoxymethyl biphenyls.

[0031] Examples of bishalogenomethyl biphenyls or bisalkoxymethyl biphenyls that can be used include 4,4'-bis(chloromethyl)biphenyl, 4,4'-bis(bromomethyl)biphenyl, 4,4'-bis(fluoromethyl)biphenyl, 4,4'-bis(iodomethyl)biphenyl, 4,4'-dimethoxymethylbiphenyl, 4,4'-diethoxymethylbiphenyl, 4,4'-dipropoxymethylbiphenyl, 4,4'-diisopropoxymethylbiphenyl, 4,4'-diisobutoxymethylbiphenyl, 4,4'-dibutoxymethylbiphenyl, and 4,4'-di-tert-butoxymethylbiphenyl. These may be used alone or in combination of two or more. The amount of bishalogenomethyl biphenyls or bisalkoxymethyl biphenyls used is preferably 0.05 to 0.8 moles, more preferably 0.1 to 0.6 moles, per mole of aniline used.

[0032] During the reaction, acidic catalysts such as hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, zinc chloride, ferric chloride, aluminum chloride, p-toluenesulfonic acid, and methanesulfonic acid may be used as needed. These may be used alone or in combination of two or more. The amount of catalyst used is preferably 0.1 to 0.8 moles per mole of aniline, more preferably 0.5 to 0.7 moles. Too much catalyst will make the reaction solution too viscous and difficult to stir, while too little will slow down the reaction. The reaction may be carried out using organic solvents such as toluene and xylene as needed, or without solvents. For example, after adding the acidic catalyst to a mixed solution of anilines and a solvent, if the catalyst contains water, the water is removed from the system by azeotropy. Subsequently, bishalogenomethyl biphenyls or bisalkoxymethyl biphenyls are added at a temperature of preferably 40-100°C, more preferably 50-80°C, over a period of preferably 1-5 hours, more preferably 2-4 hours. The reaction is then carried out at a temperature of preferably 180-240°C, more preferably 190-220°C, while removing the solvent from the system, for a period of preferably 5-30 hours, more preferably 10-20 hours. After the reaction is complete, the acidic catalyst is neutralized with an alkaline aqueous solution, and the oil layer is washed repeatedly with an insoluble organic solvent until the wastewater becomes neutral. Excess aniline and organic solvent are then removed by distillation under reduced pressure, yielding the aromatic amine resin represented by formula (4) above. Although not mentioned in Japanese Patent Publication No. 8-16151 or Japanese Patent No. 5030297, at this stage, the by-product diphenylamine is usually present in the resin in amounts of 2-10 parts by weight, depending on the amount of catalyst, raw material usage ratio, temperature, time, etc. Diphenylamine cannot be removed by distillation. Diphenylamine can be removed by heating under reduced pressure at a temperature at least above the boiling point of aniline and blowing in water vapor or a large amount of inert gas such as nitrogen gas.

[0033] If diphenylamine is included in the curable resin composition, the crosslinking structure may not be sufficiently formed, potentially leading to a significant decrease in mechanical strength. Furthermore, if diphenylamine is included in the aromatic amine resin represented by formula (4) above, the diphenylamine remains even after maleimidization, and does not contribute to the reaction, remaining in the cured product. This can lead to bleed-out during long-term use and a decrease in thermal decomposition resistance. Therefore, the diphenylamine content is preferably 1 part by weight or less, more preferably 0.5 parts by weight or less, and even more preferably 0.2 parts by weight or less.

[0034] The method for obtaining the aromatic amine resin represented by formula (5) above is not particularly limited, but for example, in Japanese Patent Publication No. 4-75222, the n=1 compound of formula (5) is obtained as the main component by reacting aniline with m-diisopropenylbenzene or m-di(α-hydroxyisopropyl)benzene at 180-250°C in the presence of an acidic catalyst. The n=1 compound contains three isomers: symmetrical compounds with the same orientation to two aniline molecules, such as 1,3-bis(p-aminocumyl)benzene and 1,3-bis(o-aminocumyl)benzene, and asymmetrical compounds with different orientations to two aniline molecules, such as 1-(o-aminocumyl)-3-(p-aminocumyl)benzene. Furthermore, n=2 to n=5 compounds are also produced as minor components, but in Japanese Patent Publication No. 4-75222, these are purified by crystallization to obtain 1,3-bis(p-aminocumyl)benzene with a purity of 98%. Furthermore, Japanese Patent Publication No. 6-37465 describes the synthesis of N,N'-(1,3-phenylene-di-(2,2-propylene)-di-p-phenylene)bismaleimide by maleimidizing 1,3-bis(p-aminocumyl)benzene to obtain a crystalline product. However, heating is required to dissolve this product in a solvent, and if left at room temperature after heating, crystals precipitate within a few hours. Therefore, crystal precipitation is possible when preparing resin compositions, and the likelihood of crystallization increases as the concentration of N,N'-(1,3-phenylene-di-(2,2-propylene)-di-p-phenylene)bismaleimide increases. To create printed circuit boards and composite materials, glass cloth or carbon fiber is impregnated with varnish and then the resin is attached. However, if crystals precipitate, the impregnation process becomes impossible. On the other hand, raising the temperature to maintain the dissolved state accelerates the reaction of the composition, shortening the pot life of the varnish.

[0035] When synthesizing the aromatic amine resin represented by formula (5) above, the acidic catalysts used include hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, zinc chloride, ferric chloride, aluminum chloride, p-toluenesulfonic acid, methanesulfonic acid, and other acidic catalysts. In this embodiment, protic acids such as hydrochloric acid, p-toluenesulfonic acid, and methanesulfonic acid are preferred. These may be used alone or in combination of two or more. The amount of catalyst used is preferably 1 to 12% by mass, more preferably 1 to 10% by mass, and particularly preferably 1 to 7% by mass, relative to 100% by mass of the aniline used. If the amount is greater than 12% by mass, there will be fewer compounds with the desired asymmetric structure, and compounds with a symmetric structure will be preferentially formed. On the other hand, if the amount is less than 1%, not only will the reaction proceed slowly, but the reaction may not be completed, which is undesirable.

[0036] The reaction may be carried out using organic solvents such as toluene and xylene as needed, or without a solvent. For example, after adding an acidic catalyst to a mixed solution of anilines and a solvent, if the catalyst contains water, it is preferable to remove the water from the system by azeotropy. Then, diisopropenylbenzene or di(α-hydroxyisopropyl)benzene is added, and the reaction is carried out at 140-190°C, preferably 160-190°C, for 5-50 hours, preferably 5-30 hours, while removing the solvent from the system. If the reaction temperature is too high, the asymmetric structure will recombine after formation, and the target structure will be preferentially formed, preventing the desired solvent solubility and electrical properties from being exhibited. When di(α-hydroxyisopropyl)benzene is used, water is produced as a by-product, so it is removed from the system by azeotropic reaction with the solvent during heating. After the reaction is complete, the acidic catalyst is neutralized with an alkaline aqueous solution, and then a water-insoluble organic solvent is added to the oil layer and the washing is repeated until the wastewater becomes neutral, and then the solvent and excess anilines are removed under heated reduced pressure. When activated clay or ion exchange resin is used, the reaction solution is filtered after the reaction is complete to remove the catalyst. Furthermore, depending on the reaction temperature and the type of catalyst, diphenylamine may be produced as a by-product, so it is preferable to remove it as needed. The diphenylamine derivative is removed to 1% by mass or less, preferably 0.5% by mass or less, and more preferably 0.2% by mass or less, under high temperature and high vacuum conditions, or by means such as steam distillation.

[0037] Examples of anilines used in the production of aromatic amine resins include aniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 2-ethylaniline, 3-ethylaniline, 4-ethylaniline, 2,3-dimethylaniline, 2,4-dimethylaniline, 2,5-dimethylaniline, 2,6-dimethylaniline, 3,4-dimethylaniline, 3,5-dimethylaniline, 2-propylaniline, 3-propylaniline, 4-propylaniline, 2-isopropylaniline, 3-isopropylaniline, 4-isopropylaniline, 2-ethyl-6-methylaniline, 2-sec-butylaniline, 2-tert-butylaniline, 4-butylaniline, 4-sec-butylaniline, 4-tert-butylaniline, 2,3-diethylaniline, 2,4-diethylaniline, 2,5-diethylaniline, 2,6-diethylaniline, 2-isopropyl-6-methylaniline, and 4-aminobiphenyl. These can be used individually or in combination of two or more.

[0038] The maleimide resin represented by formula (2) above is obtained by adding or dehydrating and condensing the aromatic amine resin obtained by the above process with maleic acid or maleic anhydride (hereinafter also referred to as "maleic anhydride") in the presence of a solvent and a catalyst.

[0039] Since the water generated during the reaction must be removed from the system, it is preferable to use a solvent that is not water-soluble. Examples 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, but are not limited to these, and two or more may be used in combination.

[0040] In addition, a non-water-soluble solvent can be used in combination with the above-mentioned non-water-soluble solvent. Examples include dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, and N-methyl-2-pyrrolidone, and two or more of these may be used in combination. When using a non-water-soluble solvent, it is preferable to use one with a higher boiling point than the non-water-soluble solvent used in combination.

[0041] Furthermore, the catalyst used in the reaction is an acidic catalyst and is not particularly limited, but examples include p-toluenesulfonic acid, hydroxy-p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, and phosphoric acid. The amount of acidic catalyst used is usually 0.1 to 10% by mass, preferably 1 to 5% by mass, relative to the aromatic amine resin.

[0042] For example, an aromatic amine resin represented by formulas (4) and (5) above is dissolved in toluene and N-methyl-2-pyrrolidone, maleic anhydride is added to produce amical, and then p-toluenesulfonic acid is added, and the reaction is carried out under reflux conditions while removing the water produced from the system.

[0043] Alternatively, maleic anhydride is dissolved in toluene, and under stirring, an N-methyl-2-pyrrolidone solution of the aromatic amine resin represented by formulas (4) and (5) above is added to produce amitic acid. Then, p-toluenesulfonic acid is added, and the reaction is carried out under reflux conditions while removing the water produced from the system.

[0044] Alternatively, maleic anhydride is dissolved in toluene, p-toluenesulfonic acid is added, and the N-methyl-2-pyrrolidone solution of the aromatic amine resin represented by formulas (4) and (5) above is added dropwise under stirring and reflux conditions, while removing any water that forms an azeotrope from the system and returning the toluene to the system as the reaction proceeds (this completes the first stage reaction).

[0045] In either method, maleic anhydride is typically used in an amount of 1.0 to 3.0 equivalents, preferably 1.2 to 2.0 equivalents, relative to the amino group of the aromatic amine resin represented by formulas (4) and (5) above.

[0046] To reduce the amount of unclosed amic acid, after the maleimide reaction listed above, water is added to the reaction solution to separate it into a resin solution layer and an aqueous layer. Excess maleic acid, maleic anhydride, aprotic polar solvent, and catalyst are dissolved in the aqueous layer, so these are removed by liquid-liquid extraction, and the same procedure is repeated to thoroughly remove excess maleic acid, maleic anhydride, aprotic polar solvent, and catalyst. The catalyst is then added back to the maleimide resin solution in the organic layer from which the excess maleic acid, maleic anhydride, aprotic polar solvent, and catalyst have been removed, and the dehydration and ring-closing reaction of the remaining amic acid is carried out again under heated reflux conditions to obtain a maleimide resin solution with a low acid value (the above is the second stage reaction).

[0047] The re-dehydration and ring-closing reaction takes approximately 1 to 5 hours, preferably 1 to 3 hours, and the aforementioned aprotic polar solvent may be added as needed. After the reaction is complete, the mixture is cooled and washed with water repeatedly until the water becomes neutral. Then, the water is removed by azeotropic dehydration under reduced pressure, and the solvent may be removed by distillation or another solvent may be added to adjust the resin solution to the desired concentration, or the solvent may be completely removed to obtain the solid resin.

[0048] The maleimide resin represented by formula (2) above preferably has a molecular weight distribution, and the content of n=1 as determined by GPC analysis (RI) in formula (2) above is preferably 98 area% or less, more preferably 20 to 90 area%, even more preferably 30 to 80 area%, and particularly preferably 40 to 80 area%. When the content of n=1 is 98 area% or less, the heat resistance is good. Crystallinity is reduced and solvent solubility is good. On the other hand, when the lower limit of n=1 is 20 area% or more, the viscosity of the resin solution is reduced and impregnation is good. Also, since the solvent can be removed at a low temperature when extracting it as a solid, self-polymerization is less likely to occur and handling is easy.

[0049] The following describes a method for producing maleimide resin represented by formula (3) above, but is not limited to this method.

[0050] The maleimide resin represented by formula (3) above can be synthesized, for example, by reacting a styrene-maleic acid copolymer with a compound containing two or more amino groups in its molecule and maleic anhydride.

[0051] Specifically, it can be obtained by a method that involves a first step of imidizing a styrene-maleic acid copolymer with a compound having two or more amino groups in its molecule in a solvent in the presence of a catalyst, followed by a second step of adding maleic anhydride to perform maleimidization. In the first step of imidization, by adding an excess of amino groups from the amine compound to 1 mole of acid anhydride contained in the styrene-maleic acid copolymer, gelation due to three-dimensional crosslinking during the reaction process can be prevented. In this case, the preferred range for the value (α / β) obtained by dividing the number of moles of amino groups in the raw material amine (α) by the number of moles of acid anhydride in the styrene-maleic acid copolymer (β) is 1.1 to 20, preferably 1.1 to 15, and more preferably 1.1 to 10. If the amine is below the above range, gelation will occur, making production difficult. If it is above the above range, the amount of polystyrene introduced decreases, and sufficient improvement in electrical properties cannot be expected. Examples of solvents that can be used include, but are not limited to, water-insoluble solvents such as aromatic solvents like toluene and xylene, aliphatic solvents like cyclohexane and n-hexane, ethers like diethyl ether and diisopropyl ether, ester solvents like ethyl acetate and butyl acetate, and ketone solvents like methyl isobutyl ketone and cyclopentanone. Two or more solvents may be used in combination. In addition to the water-insoluble solvents mentioned above, aprotic polar solvents may also be used in combination. Examples include dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, and N-methylpyrrolidone, and two or more of these may be used in combination. When using aprotic polar solvents, it is preferable to use those with a higher boiling point than the water-insoluble solvents used in combination. During the reaction, if necessary, catalysts such as hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, p-toluenesulfonic acid, methanesulfonic acid, Lewis acids such as aluminum chloride and zinc chloride, solid acids such as activated clay, acid clay, white carbon, zeolite, and silica-alumina, and acidic ion exchange resins may be used. These may be used alone or in combination of two or more. The amount of catalyst used is usually 0.1 to 0.8 moles, preferably 0.2 to 0.7 moles, per mole of amino groups in the amine compound used.If too much catalyst is used, the viscosity of the reaction solution may become too high, making stirring difficult. If too little is used, the reaction may proceed slowly. In addition, basic co-catalysts such as triethylamine can be used alone or in combination as co-catalysts for imidation. When sulfonic acid is used as a catalyst, neutralization with alkali metals such as sodium hydroxide or potassium hydroxide may be performed before proceeding to the extraction step. For the extraction step, aromatic hydrocarbon solvents such as toluene or xylene may be used alone, or non-aromatic hydrocarbons such as cyclohexane or toluene may be used in combination. After extraction, the organic layer is washed with water until the wastewater is neutral, and the solvent is removed using an evaporator or the like to obtain the maleimide resin represented by formula (3) above.

[0052] Styrene-maleic acid copolymers are obtained by copolymerizing styrene and maleic anhydride. Any known polymerization method may be used, including radical polymerization, coordination polymerization, and various living polymerization methods. For example, they can be obtained by reacting styrene and maleic anhydride in toluene in the presence of a radical polymerization initiator. The resulting polymer may be a random polymer, a periodic copolymer, a block polymer, or an alternating copolymer. The stereoregularity of the polystyrene segments may be syndiotactic, atactic, isotactic, etc. The molecular weight is preferably 500 to 50000, more preferably 750 to 40000, even more preferably 1000 to 30000, and particularly preferably 1500 to 20000. If the molecular weight is less than 500, the resulting product becomes easily volatile, and the weight of the resin component decreases during heating, making it difficult to apply to the manufacturing process of substrate materials. Furthermore, if the molecular weight is greater than 30,000, it becomes difficult to expand sales during manufacturing, and purification by washing with water becomes difficult.

[0053] Next, we will explain cyanate ester resins.

[0054] Conventional known cyanate ester resins can be used as the cyanate ester resin. Specific examples of cyanate ester resins include, but are not limited to, cyanate ester compounds obtained by reacting polycondensates of phenols and various aldehydes, polymers of phenols and various diene compounds, polycondensates of phenols and ketones, polycondensates of bisphenols and various aldehydes, phenols and aromatic dimethanols, phenols and aromatic dichloromethyls, phenols and aromatic bisalkoxymethyls, etc., with cyanide halides. These may be used individually or in combination of two or more.

[0055] Examples of the above-mentioned phenols include phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, and dihydroxynaphthalene.

[0056] Examples of the above-mentioned aldehydes include formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, and the like.

[0057] Examples of the various diene compounds mentioned above include dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, and the like.

[0058] Examples of the above-mentioned ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, and benzophenone.

[0059] Examples of aromatic dimethanols include benzenedimethanol and biphenyldimethanol; examples of aromatic dichloromethyls include α,α'-dichloroxylene and bischloromethylbiphenyl; and examples of aromatic bisalkoxymethyls include bismethoxymethylbenzene, bismethoxymethylbiphenyl, and bisphenoxymethylbiphenyl.

[0060] Examples of cyanate ester resins include those represented by the following formulas (6), (7), and (8).

[0061] [ka]

[0062] (In formula (6), R6 to R9 may be the same or different, and represent an alkyl group or phenyl group having 1 to 10 carbon atoms. Y represents one of the structures represented by the following formulas (6-a) to (6-f).)

[0063] [ka]

[0064] (In equations (6-a) to (6-f), * represents a bond to a benzene ring.)

[0065] [ka]

[0066] (In formula (7), R 10 ~R 13 The repeating elements may be the same or different, and represent a hydrogen atom, an alkyl group with 1 to 10 carbon atoms, or a phenyl group. j is the number of repeating elements, and its average value is j. ave is 1 <j ave <5.

[0067] [ka]

[0068] (In equation (8), Z represents one of the structures represented by equations (8-a) to (8-c) below. j is the number of repetitions, and its average value j) ave is 1 <j ave <5.

[0069] [ka]

[0070] (In equations (8-a) to (8-c), * represents a bond to the naphthalene ring.)

[0071] In the curable resin composition of the present invention, the ratio of maleimide resin to cyanate ester resin is preferably 5.0 to 80.0% by weight of cyanate ester resin, more preferably 10.0 to 70.0% by weight, even more preferably 20.0 to 60.0% by weight, and particularly preferably 30.0 to 55.0% by weight, relative to the total weight of maleimide resin and cyanate ester resin. If the amount of cyanate ester resin is less than the above range, the heat resistance deteriorates. On the other hand, if the amount of cyanate ester resin is more than the above range, the dielectric properties deteriorate. When the amount of cyanate ester resin is within the above range, a cured product with excellent properties of both heat resistance and dielectric properties can be obtained without deterioration of both.

[0072] Next, we will explain the curable resin represented by the following formula (1). [ka]

[0073] In formula (1) above, each of the multiple R1s independently represents a hydrocarbon group having 1 to 50 carbon atoms, preferably a hydrocarbon group having 1 to 5 carbon atoms or a hydrocarbon group represented by the following formula (a-0), more preferably a hydrocarbon group having 1 to 3 carbon atoms or a structure represented by the following formula (a-0), and even more preferably an alkyl group having 1 to 3 carbon atoms or a structure represented by the following formula (a-0). Each of the multiple R2s independently represents a hydrocarbon group having 1 to 10 carbon atoms, preferably a hydrocarbon group having 1 to 5 carbon atoms, and more preferably a hydrocarbon group having 1 to 3 carbon atoms. When the number of carbon atoms is 10 or less, molecular vibration is less likely to occur when exposed to high frequency, resulting in excellent electrical properties. Also, if it is a hydrogen atom, deterioration of dielectric properties and water absorption properties due to the formation of polar groups resulting from the oxidation reaction of alkyl groups during high-temperature storage tests can be suppressed. Each of the multiple ls independently represents an integer from 0 to 4, preferably 0. Each of the multiple ms independently represents an integer from 0 to 4, and the average value of m is m ave is 0≦m ave ≤ 4. ave This can be calculated from the raw material mixing ratio or from the NMR analysis results. From the viewpoint of solvent solubility and heat resistance, 0 ≤ m ave Preferably, ≤3, and 0 ≤ m ave It is more preferable that m ≤ 2. ave If the value is greater than 4, steric hindrance increases, which may reduce the hardening properties.

[0074] [ka]

[0075] In formula (a) above, * represents the bonding position to the fluorene structure in formula (1) above. There are multiple R 14Each of these independently represents a hydrocarbon group having 1 to 5 carbon atoms, preferably a hydrocarbon group having 1 to 3 carbon atoms. When the number of carbon atoms is 5 or less, molecular vibration is less likely to occur when exposed to high frequencies, resulting in excellent electrical properties. In addition, if it is a hydrogen atom, deterioration of dielectric properties and water absorption properties due to the formation of polar groups resulting from the oxidation reaction of alkyl groups during high-temperature storage tests can be suppressed. E1 represents a direct bond or a methylene group. E2 and E3 represent a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or a substituted or unsubstituted phenyl group. Each of the u independently represents an integer from 0 to 2. The multiple s each independently represents an integer from 0 to 5, preferably 0 or 1.

[0076] The hydrocarbon group represented by formula (a) above is preferably one or more selected from the following formulas (a-1) to (a-8).

[0077] [ka]

[0078] In the above equations (a-1) to (a-8), * represents the bonding position to the fluorene structure in equation (1). There are multiple R 14 Each of the 's's independently represents a hydrocarbon group having 1 to 5 carbon atoms, preferably a hydrocarbon group having 1 to 3 carbon atoms. When the number of carbon atoms is 5 or less, molecular vibration is less likely to occur when exposed to high frequencies, resulting in excellent electrical properties. Furthermore, when it is a hydrogen atom, the deterioration of dielectric properties and water absorption properties due to the formation of polar groups resulting from the oxidation reaction of alkyl groups during high-temperature storage tests can be suppressed. Each of the multiple 's's independently represents an integer from 0 to 5, preferably 0 or 1.

[0079] Formulas (a-1) to (a-8) above may consist of only one type or a mixture of multiple types. For example, the value (X / Y) obtained by dividing the number of substituents (X) represented by formula (a-2) above by the number of substituents (Y) represented by formula (a-1) above is preferably 0.25 ≤ (X / Y) ≤ 8, more preferably 0.5 ≤ (X / Y) ≤ 6, particularly preferably 0.75 ≤ (X / Y) ≤ 4, and most preferably 0.75 ≤ (X / Y) ≤ 2. The higher the content of substituents represented by formula (a-2), the better the heat resistance, low water absorption, and low dielectric properties. The value of (X / Y) can be calculated from the raw material ratio when synthesizing the compound represented by formula (A) described later.

[0080] The method for producing the curable resin represented by formula (1) above is not particularly limited, but it can be obtained by reacting a compound represented by the following formula (A) with a mixture containing the compound represented by the following formula (B).

[0081] [ka]

[0082] In the above formula (A), each of the multiple R1s independently represents a hydrocarbon group having 1 to 50 carbon atoms, preferably a hydrocarbon group having 1 to 5 carbon atoms or a structure represented by the following formula (1-1), more preferably a hydrocarbon group having 1 to 3 carbon atoms or a structure represented by the following formula (1-1), and even more preferably an alkyl group having 1 to 3 carbon atoms or a structure represented by the following formula (1-1). Each of the multiple ms independently represents an integer from 0 to 4. The average value of m is m ave is 0≦m ave ≤ 4. ave This can be calculated from the raw material mixing ratio or from the NMR analysis results. From the viewpoint of solvent solubility and heat resistance, 0 ≤ m ave Preferably, ≤3, and 0 ≤ m ave It is more preferable that m ≤ 2. ave If the value is greater than 4, steric hindrance increases, which may reduce the hardening properties.

[0083] [ka]

[0084] In formula (a) above, * represents the bonding position to the fluorene structure in formula (1) above. There are multiple R 14 Each of these independently represents a hydrocarbon group having 1 to 5 carbon atoms, preferably a hydrocarbon group having 1 to 3 carbon atoms. When the number of carbon atoms is 5 or less, molecular vibration is less likely to occur when exposed to high frequencies, resulting in excellent electrical properties. In addition, if it is a hydrogen atom, deterioration of dielectric properties and water absorption properties due to the formation of polar groups resulting from the oxidation reaction of alkyl groups during high-temperature storage tests can be suppressed. E1 represents a direct bond or a methylene group. E2 and E3 represent a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or a substituted or unsubstituted phenyl group. Each of the u independently represents an integer from 0 to 2. The multiple s each independently represents an integer from 0 to 5, preferably 0 or 1.

[0085] The hydrocarbon group represented by formula (a) above is preferably one or more selected from formulas (a-1) to (a-6), and formulas (a-1) to (a-6) may be just one or a mixture of multiple types. For example, the value (X / Y) obtained by dividing the number of substituents introduced (X) represented by formula (a-2) above by the number of substituents introduced (Y) represented by formula (a-1) above is preferably 0.25 ≤ (X / Y) ≤ 8, more preferably 0.5 ≤ (X / Y) ≤ 6, particularly preferably 0.75 ≤ (X / Y) ≤ 4, and most preferably 0.75 ≤ (X / Y) ≤ 2. The higher the content of substituents represented by formula (a-2), the better the heat resistance and low water absorption.

[0086] [ka]

[0087] A mixture containing the compound represented by formula (B) above includes a compound in which the orientation between the vinyl group and the halomethyl group is meta and a compound in which the orientation between the vinyl group and the halomethyl group is para. For a mixture containing the compound represented by formula (B), the ratio of the meta compound to the para compound is preferably 5:95 to 60:40, more preferably 20:80 to 60:40, more preferably 30:70 to 60:40, even more preferably 40:60 to 60:40, and particularly preferably 45:55 to 55:45.

[0088] In formula (B) above, each of the multiple R2s independently represents a hydrocarbon group having 1 to 5 carbon atoms, preferably a hydrocarbon group having 1 to 3 carbon atoms. When the number of carbon atoms is 5 or less, molecular vibration is less likely to occur when exposed to high frequencies, resulting in excellent electrical properties. Furthermore, if it is a hydrogen atom, deterioration of dielectric properties and water absorption properties due to the formation of polar groups resulting from the oxidation reaction of alkyl groups during high-temperature storage tests can be suppressed. X represents a halogen atom, and from the viewpoint of reactivity and waste generation suppression, it is preferably a bromine atom or a chlorine atom, and more preferably a chlorine atom. Each l independently represents an integer from 0 to 4, preferably 0.

[0089] When synthesizing the curable resin represented by formula (1) above, when α is the number of moles of the compound represented by formula (A) above and β is the number of moles of the mixture containing the compound represented by formula (B) above, it is preferable that β / α is 1.8 or more and 2.1 or less, more preferably 1.8 or more and 2.0 or less, and particularly preferably 1.8 or more and 1.95 or less. If β / α is less than 1.8, the compound represented by formula (A) above remains unreacted, which may reduce the toughness of the cured film and worsen the dielectric properties. This is because the unreacted compound represented by formula (A) above does not have a crosslinkable structure, and oxygen reacts with the methylene structure at position 9 of the compound represented by formula (A) above to generate a ketone, increasing its polarity. If β / α is greater than 2.1, halogen elements in the mixture containing the compound represented by formula (B) above, which could not be completely removed by purification, may desorb during curing (e.g., at temperatures of 175°C or higher) or during high-temperature and high-humidity testing (e.g., 85°C, 85% humidity or 120°C, 100% humidity), potentially leading to corrosion of copper wiring. The amount of residual halogen contained in the compound of this embodiment is preferably 1 to 10,000 ppm, more preferably 1 to 3,000 ppm, and even more preferably 1 to 2,000 ppm.

[0090] The reaction between the compound represented by formula (A) and a mixture containing the compound represented by formula (B) will be described in detail. The curable resin represented by formula (1) is obtained by reacting the compound represented by formula (A) and a mixture containing the compound represented by formula (B) in an aprotic polar solvent in the presence of a basic catalyst. Examples of aprotic polar solvents include dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, and N-methylpyrrolidone, and two or more may be used in combination. In addition, a water-insoluble solvent may be used in combination as needed. Examples of water-insoluble solvents 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, but are not limited to these, and two or more may be used in combination. The catalyst is not particularly limited, but basic catalysts such as sodium hydroxide, potassium hydroxide, and potassium carbonate are examples. The order in which the compound represented by formula (A), the mixture containing the compound represented by formula (B), and the base are added can be changed as needed, but it is preferable to add the compound represented by formula (A), an aprotic polar solvent, and a base, and after the compound represented by formula (A) has been sufficiently ionized, add the mixture containing the compound represented by formula (B). If the reaction is carried out without using an aprotic polar solvent, the reaction rate will decrease significantly. When an aprotic polar solvent is not used, the reaction is generally carried out using an interlayer transfer catalyst. In this case, the raw materials are dissolved in a water-insoluble solvent such as toluene, and the mixture containing the compound represented by formula (A) and the compound represented by formula (B) is reacted in the presence of a base catalyst such as an aqueous sodium hydroxide solution and an interlayer transfer catalyst such as tetrabutylammonium bromide.In this case, it is difficult to completely remove interlayer transfer catalysts such as tetrabutylammonium bromide, making it difficult to achieve low dielectric properties (low dielectric constant and low dielectric loss tangent). Furthermore, residual interlayer transfer catalysts may cause problems such as ion migration when substrate materials using the compound of this embodiment are subjected to long-term moist heat reliability tests. The reaction temperature is preferably 0 to 120°C, more preferably 0 to 100°C, and even more preferably 0 to 80°C. Above the upper limit, self-polymerization of the compound of this embodiment may proceed, potentially leading to gelation. Below the lower limit, the reaction may not proceed sufficiently. As a post-reaction treatment, neutralization may be performed with any acid compound. Alternatively, if necessary, an alcohol compound or water may be added to the reaction solution to recover the target product as crystals. The obtained reaction solution or crystals may also be redissolved in any solvent and an extraction step may be performed. For the extraction step, aromatic hydrocarbon solvents such as toluene or xylene may be used alone, or non-aromatic hydrocarbons such as cyclohexane or toluene may be used in combination. After extraction, the organic layer is washed with water until the wastewater becomes neutral, and the solvent is removed using an evaporator or the like to obtain the desired compound.

[0091] If the compound represented by formula (A) above has the structure represented by formula (1-1) below, it is derived from fluorene and the compound represented by formula (c) or (d) below.

[0092] [ka]

[0093] In equations (c) and (d) above, there are multiple R 14Each of the following independently represents a hydrocarbon group having 1 to 5 carbon atoms, preferably a hydrocarbon group having 1 to 3 carbon atoms. When the number of carbon atoms is 5 or less, molecular vibration is less likely to occur when exposed to high frequency, resulting in excellent electrical properties. Also, if it is a hydrogen atom, deterioration of dielectric properties and water absorption properties due to the formation of polar groups resulting from the oxidation reaction of alkyl groups during high-temperature storage tests can be suppressed. Each of the following independently represents an integer from 0 to 2. The multiple s each independently represents an integer from 0 to 5, preferably 0 or 1. Z represents a hydroxyl group or a halogen atom, and from the viewpoint of reactivity and suppression of waste generation, it is preferably a hydroxyl group, a bromine atom or a chlorine atom, and more preferably a hydroxyl group or a chlorine atom. E1 represents a directly bonded or methylene group. E2 and E3 represent hydrocarbon groups of 1 to 5 carbon atoms, or substituted or unsubstituted phenyl groups. Of the compounds represented by the above formula (c) or (d), it is preferable to use the compound represented by the above formula (c) from the viewpoint of suppressing the self-polymerization reaction of the raw materials.

[0094] When reacting fluorene with the compound represented by formula (c) or (d) above, it is preferable to react 0.01 to 10 moles of the compound represented by formula (c) or (d) above with 1 mole of fluorene, more preferably 0.1 to 7.5 moles, even more preferably 0.2 to 5 moles, and most preferably 0.3 to 4 moles. If the number of moles of compound (c) or (d) reacted with fluorene is less than 0.01 moles, there is a concern that the storage stability after solvent dissolution will deteriorate, such as the precipitation of crystals when left standing for a long time after solvent dissolution. If the amount is greater than 10 moles, there is a risk of decreased heat resistance, or that the compound represented by formula (c) or (d) above will be in excess, leading to self-polymerization and a decrease in the purity of the desired product.

[0095] When reacting fluorene with the compound represented by formula (c) or (d) above, a catalyst such as hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, p-toluenesulfonic acid, methanesulfonic acid, Lewis acids such as aluminum chloride and zinc chloride, solid acids such as activated clay, acid clay, white carbon, zeolite, and silica alumina, and acidic ion exchange resins may be used as necessary. These may be used alone or in combination of two or more. The amount of catalyst used is preferably 0.1 to 40% by weight, more preferably 0.1 to 20% by weight, relative to the total weight of the fluorene and the compound represented by formula (c) or (d) above. If too much catalyst is used, the viscosity of the reaction solution may become too high, making stirring difficult, and if too little is used, the reaction may proceed slowly. The reaction may be carried out using organic solvents such as hexane, cyclohexane, octane, toluene, and xylene as needed, or it may be carried out without a solvent. For example, an acidic catalyst is added to a mixed solution of fluorene, a compound represented by formula (c) or (d) above, and a solvent (or no solvent). If the catalyst contains water, the water is removed from the system by azeotropy or the like. After that, the reaction is carried out at 40 to 300°C, preferably 50 to 250°C, for 0.5 to 40 hours. After the reaction is complete, the acidic catalyst may be neutralized with an alkaline aqueous solution, but the process can also proceed to the water washing step without neutralization. In the water washing step, a water-insoluble organic solvent is added to the oil layer and the washing is repeated until the wastewater becomes neutral.

[0096] Furthermore, with respect to the compound represented by formula (A) obtained in the above reaction, a neutralizing agent such as an alkali and an aprotic polar solvent may be added to the reaction solution, followed by the addition of a base catalyst and a mixture containing the compound represented by formula (B), to continuously convert it into a curable resin represented by formula (1).

[0097] The softening point of the compound represented by formula (A) above is preferably 150°C or lower, and more preferably 120°C or lower. When the softening point is 150°C or lower, the viscosity when it is converted to the curable resin represented by formula (1) above is lower. This makes it easier to ensure fluidity, does not impair the impregnation properties of glass cloth or carbon fiber, and facilitates B-stage processes such as prepreg formation. If the viscosity is lowered by increasing the dilution solvent, the resin may not adhere sufficiently to the fibrous material during the impregnation process.

[0098] The curable resin represented by formula (1) above can be cured on its own by heating or other means, but its performance can also be improved by adding various materials to form a curable resin composition.

[0099] The lower limit of the maleimide resin content in the total amount of the curable resin composition of this embodiment is preferably 1% by mass or more, more preferably 5% by mass or more, more preferably 10% by mass or more, more preferably 12.5% ​​by mass or more, and particularly preferably 15% by mass or more. The upper limit is preferably 99% by mass or less, more preferably 95% by mass or less, more preferably 90% by mass or less, more preferably 87.5% by mass or less, more preferably 85% by mass or less, more preferably 80% by mass or less, more preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less. The lower limit of the curable resin content represented by formula (1) in the total amount of the curable resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, more preferably 10% by mass or more, more preferably 12.5% ​​by mass or more, and particularly preferably 15% by mass or more. The upper limit is preferably 99% by mass or less, more preferably 95% by mass or less, more preferably 90% by mass or less, more preferably 87.5% by mass or less, more preferably 85% by mass or less, more preferably 80% by mass or less, more preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less. If the maleimide resin content is less than the above range, the coefficient of thermal expansion will not show a good value. If the maleimide resin content is more than the above range, the dielectric loss tangent may deteriorate. If it is within the above range, good dielectric properties can be obtained without deteriorating the coefficient of thermal expansion. If the content of the curable resin represented by formula (1) is less than the above range, the water absorption rate may increase. If the content of the curable resin represented by formula (1) is more than the above range, the cured product may become brittle. If it is within the above range, a strong cured product can be obtained, and a good water absorption rate can be obtained.

[0100] The dielectric loss tangent Df of the cured product obtained by curing the curable resin composition of this embodiment is preferably 0.0050 or less, more preferably 0.0045 or less, and particularly preferably 0.0040 or less.

[0101] [Curing accelerator] The curable resin composition of this embodiment can also have its curability improved by adding a curing accelerator. Preferred curing accelerators are anionic curing accelerators that promote the curing reaction by generating anions upon irradiation with ultraviolet light or visible light or by heating, or cationic curing accelerators that promote the curing reaction by generating cations upon irradiation with ultraviolet light or visible light or by heating.

[0102] Examples of anionic curing accelerators include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole; trialkylamines such as triethylamine and tributylamine; 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene, with 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene being preferred. Other examples include phosphines such as triphenylphosphine, tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, and quaternary ammonium salts such as hexadecyltrimethylammonium hydroxide, but are not limited to these. These can be used individually or in combination.

[0103] Examples of cationic curing accelerators include quaternary phosphonium salts such as triphenylbenzylphosphonium salt, triphenylethylphosphonium salt, and tetrabutylphosphonium salt (the counterions of the quaternary salts are halogens, organic acid ions, hydroxide ions, etc., with no particular preference, but organic acid ions and hydroxide ions are particularly preferred), tin octoate, zinc carboxylates (zinc 2-ethylhexanoate, zinc stearate, zinc behenate, zinc myristate), and zinc phosphate esters (zinc octyl phosphate, zinc stearyl phosphate), but are not limited to these. Furthermore, these may be used individually or in combination of multiple types. Among these, quaternary phosphonium salts and zinc carboxylates are preferred.

[0104] The amount of curing accelerator added is 0.01 to 5.0 parts by mass per 100 parts by mass of the curable resin composition, as needed.

[0105] [Inorganic fillers] The curable resin composition of this embodiment may contain an inorganic filler. Examples of inorganic fillers include, but are not limited to, powders such as fused silica, crystalline silica, porous silica, alumina, zircon, calcium silicate, calcium carbonate, quartz powder, silicon carbide, silicon nitride, boron nitride, zirconia, aluminum nitride, graphite, forsterite, steatite, spinel, mullite, titania, talc, clay, iron oxide asbestos, and glass powder, or inorganic fillers made by shaping these into spheres or crushed forms. Furthermore, these may be used individually or in combination of multiple types.

[0106] When obtaining a curable resin composition for semiconductor encapsulation, the amount of inorganic filler used is preferably 80 to 92 parts by mass, and more preferably 83 to 90 parts by mass, per 100 parts by mass of the curable resin composition. Furthermore, when obtaining a curable resin composition for interlayer insulating layer forming materials, copper-clad laminates, prepregs, RCCs, and other substrate materials, the amount of the above-mentioned inorganic filler used is preferably 5 to 80 parts by mass, and more preferably 10 to 60 parts by mass, per 100 parts by mass of the curable resin composition.

[0107] [Polymerization initiator] The curable resin composition of this embodiment can also have its curability improved by adding a polymerization initiator. A polymerization initiator is a compound capable of polymerizing olefin functional groups such as ethylenically unsaturated bonds, and examples include olefin metathesis polymerization initiators, anionic polymerization initiators, cationic polymerization initiators, and radical polymerization initiators. Among these, it is preferable to use a radical polymerization initiator that has both curability and appropriate stability. A radical polymerization initiator is a compound that generates radicals by irradiation with ultraviolet or visible light or by heating, and initiates a chain polymerization reaction. Examples of radical polymerization initiators that can be used include organic peroxides, azo compounds, and benzopinacols, and it is preferable to use organic peroxides because they have little effect on curing temperature control, outgassing suppression, and the electrical properties of decomposition products. However, from the viewpoint of exhibiting low dielectric properties, it is preferable not to add them.

[0108] Examples of the above organic peroxides include ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide, diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as dicumyl peroxide and 1,3-bis-(t-butylperoxyisopropyl)benzene, peroxyketals such as t-butyl peroxybenzoate and 1,1-di-t-butylperoxycyclohexane, α-cumyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, t-amyl peroxy-2-ethylhexanoate, and t-butyl peroxy Examples of such substances include alkyl peresters such as -oxy-2-ethylhexanoate, t-amyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxy-3,5,5-trimethylhexanoate, and t-amyl peroxybenzoate; peroxycarbonates such as di-2-ethylhexyl peroxydicarbonate, bis(4-t-butylcyclohexyl) peroxydicarbonate, t-butyl peroxyisopropyl carbonate, and 1,6-bis(t-butyl peroxycarbonyloxy)hexane; t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyoctoate, and lauroyl peroxide, but are not limited to these. Furthermore, these may be used individually or in combination. Among the above organic peroxides, ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, and parkervonates are preferred, with dialkyl peroxides being more preferred.

[0109] Examples of the above-mentioned azo compounds include, but are not limited to, azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), and 2,2'-azobis(2,4-dimethylvaleronitrile). Furthermore, these compounds may be used individually or in combination.

[0110] The amount of polymerization initiator added is preferably 0.01 to 5 parts by mass, and particularly preferably 0.01 to 3 parts by mass, per 100 parts by mass of the curable resin composition. If the amount of polymerization initiator used is less than 0.01 parts by mass, the molecular weight may not elongate sufficiently during the polymerization reaction, and if it is more than 5 parts by mass, dielectric properties such as dielectric constant and dielectric loss tangent may be impaired.

[0111] [Polymerization inhibitor] The curable resin composition of this embodiment may contain a polymerization inhibitor. Including a polymerization inhibitor improves storage stability and allows control of the reaction initiation temperature. Controlling the reaction initiation temperature makes it easier to ensure fluidity, prevents impregnation of glass cloth and the like, and facilitates B-stage processes such as prepreg formation. If the polymerization reaction proceeds too far during prepreg formation, problems such as difficulty in lamination during the lamination process are likely to occur.

[0112] The polymerization inhibitor may be added when synthesizing the maleimide resin or cyanate ester resin represented by formulas (2) and (3) above, or the curable resin represented by formula (1) above, or after synthesis. It may also be added when preparing the resin composition. The amount of polymerization inhibitor used is 0.008 to 1 part by mass, preferably 0.01 to 0.5 parts by mass, per 100 parts by mass of the maleimide resin represented by formulas (2) and (3) above.

[0113] Examples of polymerization inhibitors include phenol-based, sulfur-based, phosphorus-based, hindered amine-based, nitroso-based, and nitroxyl radical-based agents. Furthermore, polymerization inhibitors may be used individually or in combination of multiple types. Of these, phenol-based, hindered amine-based, nitroso-based, and nitroxyl radical-based agents are preferred in this embodiment.

[0114] Examples of the above phenolic polymerization inhibitors include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-p-ethylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, and 2,4-bis[(octylthio)methyl]-o-c Monophenols such as resols, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] [T], N,N'-Hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 3,9-bis[1,1-dimethyl-2-{β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane, bis(3,5-di-t- Bisphenols such as calcium ethyl hydroxybenzylsulfonate, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, tris-(3,Examples include, but are not limited to, high molecular weight phenols such as 5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, and tocopherol.

[0115] Examples of sulfur-based polymerization inhibitors include, but are not limited to, dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, and distearylul-3,3'-thiodipropionate.

[0116] Examples of the phosphorus polymerization inhibitors mentioned above include triphenyl phosphite, diphenylisodecyl phosphite, phenyldiisodecyl phosphite, tris(nonylphenyl) phosphite, diisodecylpentaerythritol phosphite, tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis(octadecyl) phosphite, cyclic neopentanetetraylbi(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbi(2,4-di-t-butyl-4-methylphenyl) phosphite, and bis[2-t Examples include, but are not limited to, phosphites such as -butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl]hydrogen phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0117] Examples of the above-mentioned hindered amine polymerization inhibitors include, but are not limited to, Adekastab LA-40MP, Adekastab LA-40Si, Adekastab LA-402AF, Adekastab LA-87, Adekastab LA-82, Adekastab LA-81, Adekastab LA-77Y, Adekastab LA-77G, Adekastab LA-72, Adekastab LA-68, Adekastab LA-63P, Adekastab LA-57, Adekastab LA-52, Chimassorb2020FDL, Chimassorb944FDL, Chimassorb944LD, Tinuvin622SF, TinuvinPA144, Tinuvin765, Tinuvin770DF, TinuvinXT55FB, Tinuvin111FDL, Tinuvin783FDL, and Tinuvin791FB.

[0118] Examples of the nitroso polymerization inhibitors mentioned above include, but are not limited to, p-nitrosophenol, N-nitrosodiphenylamine, ammonium salts of N-nitrosophenylhydroxyamine, (cuperone), etc. Of these, ammonium salts of N-nitrosophenylhydroxyamine (cuperone) are preferred.

[0119] Examples of the above-mentioned nitroxyl radical polymerization inhibitors include, but are not limited to, di-tert-butylnitroxide, 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-acetoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl.

[0120] [Flame retardant] The curable resin composition of this embodiment may contain a flame retardant. Examples of flame retardants include halogen-based flame retardants, inorganic flame retardants (antimony compounds, metal hydroxides, nitrogen compounds, boron compounds, etc.), and phosphorus-based flame retardants, but phosphorus-based flame retardants are preferred from the viewpoint of achieving halogen-free flame retardancy. The phosphorus-based flame retardants mentioned above may be reactive or additive types. Specific examples include phosphate esters such as trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixyllenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixyllenyl phosphate, 1,3-phenylenebis(dixyllenyl phosphate), 1,4-phenylenebis(dixyllenyl phosphate), and 4,4'-biphenyl(dixyllenyl phosphate); phosphanes such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 10(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; phosphorus-containing epoxy compounds obtained by reacting epoxy resin with the active hydrogen of the above phosphanes; and red phosphorus, but are not limited to these. Furthermore, these may be used individually or in combination of multiple types. Among the above example substances, phosphate esters, phosphans, or phosphorus-containing epoxy compounds are preferred, and 1,3-phenylenebis(dixyllenyl phosphate), 1,4-phenylenebis(dixyllenyl phosphate), 4,4'-biphenyl(dixyllenyl phosphate), or phosphorus-containing epoxy compounds are particularly preferred.

[0121] The flame retardant content is preferably in the range of 0.1 to 0.6 parts by mass per 100 parts by mass of the curable resin composition. If the content is less than 0.1 parts by mass, the flame retardancy may be insufficient, and if it is more than 0.6 parts by mass, it may adversely affect the hygroscopicity and dielectric properties of the cured product.

[0122] [Light stabilizer] The curable resin composition of this embodiment may also contain a light stabilizer. Suitable light stabilizers include hindered amine-based light stabilizers, particularly HALS. Examples of HALS include the reaction product of dibutylamine·1,3,5-triazine·N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, the reaction product of dimethyl-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine succinate, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], bis(1,2 Examples include, but are not limited to, 2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(1-octyroxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, and 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate bis(1,2,2,6,6-pentamethyl-4-piperidyl). Furthermore, these may be used individually or in combination.

[0123] The amount of light stabilizer is preferably in the range of 0.001 to 0.1 parts by mass per 100 parts by mass of the curable resin composition. If the amount is less than 0.001 parts by mass, it may be insufficient to exhibit the light stabilization effect, and if it is more than 0.1 parts by mass, it may adversely affect the hygroscopicity and dielectric properties of the cured product.

[0124] [Binder resin] The curable resin composition of this embodiment may also use a binder resin. Examples of binder resins include, but are not limited to, but include butyral resins, acetal resins, acrylic resins, epoxy-nylon resins, NBR-phenolic resins, epoxy-NBR resins, and silicone resins. Furthermore, these may be used individually or in combination of multiple types.

[0125] The amount of binder resin added is preferably within a range that does not impair the flame retardancy and heat resistance of the cured product, and is preferably 0.05 to 50 parts by mass per 100 parts by mass of the curable resin composition, and more preferably 0.05 to 20 parts by mass as needed.

[0126] [Additives] The curable resin composition of this embodiment may also contain additives. Examples of additives include modified acrylonitrile copolymers, polyethylene, fluororesins, silicone gels, silicone oils, surface treatment agents for fillers such as silane coupling agents, mold release agents, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

[0127] The amount of additive added is preferably 1,000 parts by mass or less, and more preferably 700 parts by mass or less, per 100 parts by mass of the curable resin composition.

[0128] The curable resin composition of this embodiment may further contain maleimide resins other than the maleimide resin of this embodiment, epoxy resins, active ester compounds, phenolic resins, polyphenylene ether compounds, amine resins, compounds having ethylenically unsaturated bonds, isocyanate resins, polyamide resins, cyanate ester resins other than the cyanate ester resin of this embodiment, polyimide resins, polybutadiene and its modified counterparts, polystyrene and its modified counterparts, polyethylene and its modified counterparts, benzoxazine compounds, etc., and these may be used individually or in combination of multiple types. Among these compounds, it is preferable to include maleimide resin, polyphenylene ether compounds, compounds having ethylenically unsaturated bonds, cyanate ester resins, polybutadiene and its modified counterparts, polystyrene and its modified counterparts, polyethylene and its modified counterparts, based on the balance of heat resistance, adhesion, and dielectric properties. By including these compounds, the brittleness of the cured product can be improved and adhesion to metal can be enhanced, and cracks in the package can be suppressed during reliability tests such as solder reflow and thermal cycling. The total amount of the above compounds used is preferably 10 times or less by mass, more preferably 5 times or less by mass, and most preferably 3 times or less by mass, relative to the maleimide resin of this embodiment, unless otherwise specified. Furthermore, the preferred lower limit is 0.1 times or more by mass, more preferably 0.25 times or more by mass, and even more preferably 0.5 times or more by mass. Within this range, the effects of each added compound can be enhanced while taking advantage of the dielectric properties (low dielectric loss tangent) of the curable resin composition of this embodiment. Examples of these components can be used as shown below.

[0129] [Epoxy resin] The following are examples of preferred epoxy resins, but are not limited to these. The epoxy resin may be liquid or solid, and may be used individually or in combination of multiple types.

[0130] Examples of liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, glycidylamine type epoxy resin, and epoxy resin having a butadiene structure. Specific examples include "RE310S", "RE410S" (both manufactured by Nippon Kayaku Co., Ltd., bisphenol A type epoxy resin), "RE303S", "RE304S", "RE403S", "RE404S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy resin), "HP4032", "HP4032D", "HP4032SS" (all manufactured by DIC Corporation, naphthalene type epoxy resin), "jER828US", "jER828EL", "jER825", "jER828EL" (all manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin), "jER807", "jER1750" (both manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin), and "jER152" (Mitsubishi Chemical Corporation). Examples include "630" and "630LSD" (both manufactured by Mitsubishi Chemical Corporation, glycidylamine type epoxy resins), "ZX1059" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin), "EX-721" (manufactured by Nagase ChemteX Corporation, glycidyl ester type epoxy resin), "Celoxide 2021P" (manufactured by Daicel Corporation, alicyclic epoxy resin with an ester skeleton), "PB-3600" (manufactured by Daicel Corporation, epoxy resin with a butadiene structure), "ZX1658" and "ZX1658GS" (both manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., liquid 1,4-glycidylcyclohexane type epoxy resins). These may be used individually or in combination of two or more types.

[0131] Preferred solid epoxy resins include, for example, bixylenol-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type tetrafunctional epoxy resin, cresol novolac-type epoxy resin, dicyclopentadiene-type epoxy resin, trisphenol-type epoxy resin, naphthol-type epoxy resin, biphenyl-type epoxy resin, naphthylene ether-type epoxy resin, anthracene-type epoxy resin, bisphenol A-type epoxy resin, bisphenol AF-type epoxy resin, and tetraphenylethane-type epoxy resin.Specific examples include "HP4032H" (manufactured by DIC, naphthalene-type epoxy resin), "HP-4700", "HP-4710" (both manufactured by DIC, naphthalene-type tetrafunctional epoxy resins), "N-690" (manufactured by DIC, cresol novolac-type epoxy resin), "N-695" (manufactured by DIC, cresol novolac-type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (both manufactured by DIC, dicyclopentadiene-type epoxy resins), "EXA-7311", "EXA-7311 -G3", "EXA-7311-G4", "EXA-7311-G4S", "HP-6000" (all manufactured by DIC Corporation, naphthylene ether type epoxy resin), "EPPN-502H" (manufactured by Nippon Kayaku Co., Ltd., trisphenol type epoxy resin), "NC-7000L", "NC-7300" (both manufactured by Nippon Kayaku Co., Ltd., naphthol-cresol novolac type epoxy resin), "NC-3000H", "NC-3000", "NC-3000L", "NC-3100" (all manufactured by Nippon Kayaku Co., Ltd., biphenyl aralkyl type epoxy resin) ), "XD-1000-2L", "XD-1000-L", "XD-1000-H" (all manufactured by Nippon Kayaku Co., Ltd., dicyclopentadiene type epoxy resin), "ESN475V" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., naphthol type epoxy resin), "ESN485" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., naphthol novolac type epoxy resin), "YX-4000H", "YX-4000", "YL6121" (all manufactured by Mitsubishi Chemical Corporation, biphenyl type epoxy resin), "YX-4000HK" (manufactured by Mitsubishi Chemical Corporation, bixylenol type epoxy resin) Examples include "YX-8800" (manufactured by Mitsubishi Chemical Corporation, anthracene-type epoxy resin), "PG-100", "CG-500" (manufactured by Osaka Gas Chemical Co., Ltd., fluorene-type epoxy resin), "YL-7760" (manufactured by Mitsubishi Chemical Corporation, bisphenol AF-type epoxy resin), "YL-7800" (manufactured by Mitsubishi Chemical Corporation, fluorene-type epoxy resin), "jER1010" (manufactured by Mitsubishi Chemical Corporation, solid bisphenol A-type epoxy resin), and "jER1031S" (manufactured by Mitsubishi Chemical Corporation, tetraphenylethane-type epoxy resin). These may be used individually or in combination of two or more types.

[0132] [Activated ester compounds] An active ester compound is a compound that contains at least one ester bond in its structure, with aliphatic chains, aliphatic rings, or aromatic rings bonded to both sides of the ester bond. Examples of active ester compounds include compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. These are obtained by a condensation reaction between at least one compound of a carboxylic acid compound, an acid chloride, or a thiocarboxylic acid compound and at least one compound of a hydroxy compound or a thiol compound. Particularly from the viewpoint of improving heat resistance, it is preferable that they be obtained from a carboxylic acid compound or an acid chloride and a hydroxy compound, and phenol compounds or naphthol compounds are preferred as the hydroxy compound. Active ester compounds may be used alone or in combination of two or more.

[0133] Examples of the carboxylic acid compounds mentioned above include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

[0134] Examples of the above-mentioned acid chlorides include acetyl chloride, acrylate chloride, methacrylate chloride, malonyl chloride, succinate dichloride, diglycolyl chloride, glutarate dichloride, suberic acid dichloride, sebacate dichloride, adipic acid dichloride, dodecanediol dichloride, azera oil chloride, 2,5-franzicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, and 4,4'-azodibenzoyl dichloride.

[0135] Examples of the above-mentioned phenol compounds and naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, phenol novolac, and phenol resins described later. Here, "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by the condensation of two molecules of phenol with one molecule of dicyclopentadiene.

[0136] Preferred examples of active ester compounds include active ester compounds containing a dicyclopentadiene-type diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated phenol novolac, active ester compounds containing a benzoylated phenol novolac, the compounds described in Example 2 of International Publication No. 2020 / 095829, and the compounds disclosed in International Publication No. 2020 / 059625. Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene-type diphenol structure are more preferred. The dicyclopentadiene-type diphenol structure represents a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

[0137] Commercially available active ester compounds include, for example, "EXB9451," "EXB9460," "EXB9460S," "HPC-8000-65T," "HPC-8000H-65TM," "EXB-8000L-65TM," and "EXB-8150-65T" (manufactured by DIC Corporation) as active ester compounds containing a naphthalene structure, and "EXB9416-70BK" (manufactured by DIC Corporation), and phenol no Examples of active ester compounds containing acetylated volacs include "DC808" (manufactured by Mitsubishi Chemical Corporation), examples of active ester compounds containing benzoylated phenol novolacs include "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation), examples of active ester curing agents that are acetylated phenol novolacs include "DC808" (manufactured by Mitsubishi Chemical Corporation), and examples of phosphorus atom-containing active ester curing agents include "EXB-9050L-62M" manufactured by DIC Corporation.

[0138] Regarding the blending ratio of the active ester compound and epoxy resin, the ratio of the active ester equivalent (α) to the epoxy equivalent (β) (α / β) is preferably 0.5 to 1.5, more preferably 0.8 to 1.2, and even more preferably 0.90 to 1.10. If it falls outside the above range, there is a risk that excess epoxy groups or active ester groups will remain in the system, which may lead to deterioration of properties in high-temperature storage tests (e.g., 150°C, 1000 hours) or long-term reliability tests under high-temperature and high-humidity conditions (e.g., temperature: 85°C, humidity: 85%).

[0139] [Phenolic resin] Phenolic resins are compounds having two or more phenolic hydroxyl groups in their molecule. Examples of phenolic resins include, but are not limited to, reaction products of phenols and aldehydes, reaction products of phenols and diene compounds, reaction products of phenols and ketones, reaction products of phenols and substituted biphenyls, reaction products of phenols and substituted phenyls, and reaction products of bisphenols and aldehydes. Furthermore, these can be used individually or in combination of multiple types. Specific examples of each of the above ingredients are given below, but this list is not exhaustive. <Phenols> Phenols, alkyl-substituted phenols, aromatic-substituted phenols, hydroquinones, resorcinols, naphthols, alkyl-substituted naphthols, dihydroxybenzenes, alkyl-substituted dihydroxybenzenes, dihydroxynaphthalenes, etc. <Aldehydes> Formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural, etc. <Diene compounds> Dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc. <Ketones> Acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, fluorenone, etc. <Substituted biphenyls> 4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, 4,4'-bis(hydroxymethyl)-1,1'-biphenyl, etc. <Substituted Phenyl Groups> 1,4-Bis(chloromethyl)benzene, 1,4-Bis(methoxymethyl)benzene, 1,4-Bis(hydroxymethyl)benzene, etc.

[0140] [Polyphenylene ether compounds] From the viewpoint of heat resistance and electrical properties, the polyphenylene ether compound is preferably a polyphenylene ether compound having an ethylenically unsaturated bond, and more preferably a polyphenylene ether compound having an acrylic group, a methacrylic group, or a styrene structure. Commercially available products include SA-9000 (manufactured by SABIC, a polyphenylene ether compound having a methacrylic group), OPE-2St 1200, and OPE-2St 2200 (manufactured by Mitsubishi Gas Chemical Company, a polyphenylene ether compound having a styrene structure). The number-average molecular weight (Mn) of the polyphenylene ether compound is preferably 500 to 5000, more preferably 2000 to 5000, and even more preferably 2000 to 4000. If the molecular weight is less than 500, the heat resistance of the cured product tends not to be sufficient. If the molecular weight is greater than 5000, the melt viscosity increases, and sufficient fluidity cannot be obtained, which tends to lead to molding defects. In addition, the reactivity decreases, the curing reaction takes a long time, the amount of unreacted material that is not incorporated into the curing system increases, the glass transition temperature of the cured product decreases, and the heat resistance of the cured product tends to decrease. If the number-average molecular weight of the polyphenylene ether compound is between 500 and 5000, it is possible to achieve excellent heat resistance and moldability while maintaining excellent dielectric properties. Specifically, the number-average molecular weight can be measured using methods such as gel permeation chromatography.

[0141] Polyphenylene ether compounds may be obtained by polymerization reactions, or by redistributing high molecular weight polyphenylene ether compounds with a number average molecular weight of approximately 10,000 to 30,000. Alternatively, these may be used as raw materials and reacted with compounds having ethylenically unsaturated bonds, such as methacrylic chloride, acrylic chloride, and chloromethylstyrene, to impart radical polymerizability. Polyphenylene ether compounds obtained by redistribution reactions can be obtained, for example, by heating a high molecular weight polyphenylene ether compound in a solvent such as toluene in the presence of a phenolic compound and a radical initiator to induce a redistribution reaction. Polyphenylene ether compounds obtained by such redistribution reactions are preferable because they maintain even higher heat resistance due to having hydroxyl groups derived from phenolic compounds that contribute to curing at both ends of the molecular chain, and because functional groups can be introduced to both ends of the molecular chain even after modification with compounds having ethylenically unsaturated bonds. Furthermore, polyphenylene ether compounds obtained by polymerization reactions are preferable because they exhibit excellent fluidity.

[0142] The molecular weight of polyphenylene ether compounds can be adjusted by adjusting polymerization conditions, etc., in the case of polyphenylene ether compounds obtained by polymerization reactions. In the case of polyphenylene ether compounds obtained by redistribution reactions, the molecular weight of the resulting polyphenylene ether compound can be adjusted by adjusting the conditions of the redistribution reaction, etc. More specifically, this can be done by adjusting the amount of phenolic compound used in the redistribution reaction. That is, the higher the amount of phenolic compound used, the lower the molecular weight of the resulting polyphenylene ether compound. In this case, poly(2,6-dimethyl-1,4-phenylene ether) can be used as the high molecular weight polyphenylene ether compound that undergoes the redistribution reaction. Furthermore, the phenolic compound used in the above redistribution reaction is not particularly limited, but polyfunctional phenolic compounds having two or more phenolic hydroxyl groups in the molecule, such as bisphenol A, phenol novolac, and cresol novolac, are preferably used. These may be used individually or in combination of two or more.

[0143] The polyphenylene ether compound content in the curable resin composition is preferably 10% to 80% by mass, more preferably 20% to 70% by mass, even more preferably 30% to 60% by mass, and particularly preferably 40% to 50% by mass.

[0144] [Amine resin] Amine resins are compounds that have two or more amino groups in their molecule. Examples of amine resins include diaminodiphenylmethane, diaminodiphenylsulfone, isophoronediamine, naphthalenediamine, aniline novolac (reaction product of aniline and formalin), N-methylaniline novolac (reaction product of N-methylaniline and formalin), orthoethylaniline novolac (reaction product of orthoethylaniline and formalin), reaction product of 2-methylaniline and formalin, reaction product of 2,6-diisopropylaniline and formalin, reaction product of 2,6-diethylaniline and formalin, reaction product of 2-ethyl-6-ethylaniline and formalin, reaction product of 2,6-dimethylaniline and formalin, and those obtained by the reaction of aniline with xylylene chloride. Examples of aniline resins include, but are not limited to, aniline and substituted biphenyls (such as 4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl) as described in Japanese Patent Publication No. 6429862, aniline and substituted phenyls (such as 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene), 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, aniline and diisopropenylbenzene, and dimer amines. Furthermore, these may be used individually or in combination.

[0145] [Isocyanate resin] Isocyanate resins are compounds that have two or more isocyanate groups in their molecule. Examples of isocyanate resins include, but are not limited to, aromatic diisocyanates such as p-phenylenediisocyanate, m-phenylenediisocyanate, p-xylenediisocyanate, m-xylenediisocyanate, 2,4-tollylenediisocyanate, 2,6-tollylenediisocyanate, 4,4'-diphenylmethanediisocyanate, and naphthalenediisocyanate; aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylenediisocyanate, 4,4'-dicyclohexylmethanediisocyanate, hydrogenated xylenediisocyanate, norbornenediisocyanate, and lysinediisocyanate; biuret compounds of one or more isocyanate monomers; or isocyanates obtained by trimerizing the above diisocyanate compounds; and polyisocyanates obtained by urethane reaction between the above isocyanate compounds and polyol compounds. Furthermore, these can be used individually or in combination.

[0146] [Polyamide resin] Examples of polyamide resins include reaction products of one or more of diamines, diisocyanates, or oxazolines with dicarboxylic acids, reaction products of diamines and acid chlorides, and ring-opening polymers of lactam compounds. These can be used individually or in combination. Specific examples of each of the above ingredients are given below, but this list is not exhaustive. <Diamine> Ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-diaminopentane, 2-methyl 1,8-diaminooctane, dimer amine, cyclohexanediamine, bis-(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, xylylenediamine, norbornanediamine, isophoronediamine, bisaminomethyltricyclodecane, phenylenediamine, diethyltoluenediamine, naphthalenediamine, diaminodiphenylmethane, bis(4-amino-3,5-dimethylphenyl)methane, bis(4-amino-3,5-diethylphenyl)methane 4,4'-methylenebis-o-toluidine, 4,4'-methylenebis-o-ethylaniline, 4,4'-methylenebis-2-ethyl-6-methylaniline, 4,4'-methylenebis-2,6-diisopropylaniline, 4,4-ethylenedianiline, 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-amino [phenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, 9,9-bis(4-aminophenyl)fluorene, 2,7-diaminofluorene, aminobenzylamine, diaminobenzophenone, etc. <Diisocyanate> Benzene diisocyanate, toluene diisocyanate, 1,3-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)cyclohexane, bis(4-isocyanatophenyl)methane, isophorone diisocyanate, 1,3-bis(2-isocyanato-2-propyl)benzene, 2,2-bis(4-isocyanatophenyl)hexafluoropropane, dicyclohexylmethane-4,4'-diisocyanate, etc. <Dicarboxylic acid> Oxalic acid, malonic acid, succicic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanediic acid, dodecanediic acid, terephthalic acid, isophthalic acid, 5-hydroxyisophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, cyclohexanedicarboxylic acid, biphenyldicarboxylic acid, naphthalenedicarboxylic acid, benzophenonedicarboxylic acid, francicarboxylic acid, 4,4'-dicarboxydiphenyl ether, 4,4'-dicarboxydiphenyl sulfide, etc. <Acid chlorides> Acetyl chloride, acrylate chloride, methacrylate chloride, malonyl chloride, succinate dichloride, diglycolyl chloride, glutarate dichloride, suberate dichloride, sebacate dichloride, adipic acid dichloride, dodecanediol dichloride, azera oil chloride, 2,5-franzicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesinate chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, 4,4'-azodibenzoyl dichloride, etc. <Lactam> ε-caprolactam, ω-undecanlactam, ω-laurolactam, etc.

[0147] [Polyimide resin] Examples of polyimide resins include, but are not limited to, the reaction products of the above-mentioned diamine and the tetracarboxylic dianhydride exemplified below. Furthermore, these can be used individually or in combination. <Tetracarboxylic acid dianhydride> 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methylcyclohexene-1,2-dicarboxylic acid anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 2,2',3,3'-benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 2,2',3, 3'-Biphenyltetracarboxylic acid dianhydride, methylene-4,4'-diphthalic acid dianhydride, 1,1-ethylidene-4,4'-diphthalic acid dianhydride, 2,2'-propyridene-4,4'-diphthalic acid dianhydride, 1,2-ethylene-4,4'-diphthalic acid dianhydride, 1,3-trimethylene-4,4'-diphthalic acid dianhydride, 1,4-tetramethylene-4,4'-diphthalic acid dianhydride, 1,5-pentamethylene-4,4'-diphthalic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride, thio-4,4'-diphthalic acid dianhydride, sulfonyl-4,4'-diphthalic acid Dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]meth Dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 3,4,9,10-Perylenetetracarboxylic dianhydride, 2,3,6,7-Anthracenetetracarboxylic dianhydride, 1,2,7,8-Phenanthrenetetracarboxylic dianhydride, Ethylenetetracarboxylic dianhydride, 1,2,3,4-Butanetetracarboxylic dianhydride, 1,2,3,4-Cyclobutanetetracarboxylic dianhydride, Cyclopentanetetracarboxylic dianhydride, Cyclohexane-1,2,3,4-Tetracarboxylic dianhydride, Cyclohexane-1,2,4,5-Tetracarboxylic dianhydride Tracarboxylic acid dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic acid dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 2,2-propyridene -4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2,2,2]octo-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, rel-[1S,5R,6R]-3-oxabicyclo[3,2 ,1] Octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, ethylene glycol-bis-(3,4-dicarboxylic acid anhydride phenyl) ether, 4,4'-biphenylbis(trimellitic acid monoester anhydride), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, etc.

[0148] [Maleimide resin] The curable resin composition of this embodiment may contain maleimide resins other than the maleimide resin of this embodiment, specifically maleimide resins with a maleimide equivalent of less than 150 g / eq. or greater than 1200 g / eq., for example, 4,4'-diphenylmethanebismaleimide, polyphenylmethanemaleimide, m-phenylenebismaleimide, 2,2'-bis[4-(4-maleimoidphenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, 4,4'-diphenyletherbismaleimide, 4,4'-diphenylsulfonebismaleimide, 1,3-bis(3-maleimoidphenoxy)benzene, 1,3-bis(4-maleimoidphenoxy)benzene), and Zylok-type maleimide resins (anilix). Maleimide (manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenyl aralkyl type maleimide resin (solidified by solvent distillation under reduced pressure of a resin solution containing maleimide resin (M2) described in Example 4 of Japanese Patent Publication No. 2009-001783), bisaminocumylbenzene type maleimide (maleimide resin described in International Publication No. 2020 / 054601), maleimide resin having an indan structure as described in Japanese Patent No. 6629692 or International Publication No. 2020 / 217679, MATERIAL STAGE Vol. 18, No. 12 2019 "~Continued Epoxy Resin CAS Number Story~ Curing Agent CAS Number Memo No. 31 Bismaleimide (1)" and MATERIAL STAGE Vol. 19, No. 2 2019 "~Continued Epoxy Resin CAS Number Story~ Curing Agent CAS Number Memo No. 32" Examples include, but are not limited to, the maleimide resins described in "Bismaleimide (2)". Furthermore, these may be used individually or in combination.

[0149] [Polybutadiene and its modified forms] Polybutadiene and its modified products are compounds that contain polybutadiene or a structure derived from polybutadiene within their molecule. The structure derived from polybutadiene may have some or all of its unsaturated bonds converted to single bonds by hydrogenation. Examples of polybutadiene and its modified products include, but are not limited to, polybutadiene, hydroxyl-terminated polybutadiene, terminally (meth)acrylated polybutadiene, carboxylic acid-terminated polybutadiene, amine-terminated polybutadiene, and styrene-butadiene rubber. These may be used individually or in combination. Of these, polybutadiene or styrene-butadiene rubber is preferred from the viewpoint of dielectric properties. Examples of styrene-butadiene rubber (SBR) include RICON-100, RICON-181, RICON-184 (all manufactured by Clay Valley Corporation), and 1,2-SBS (manufactured by Nippon Soda Co., Ltd.), while examples of polybutadiene include B-1000, B-2000, and B-3000 (all manufactured by Nippon Soda Co., Ltd.). The weight-average molecular weight of polybutadiene and styrene-butadiene rubber is preferably 500 to 10000, more preferably 750 to 7500, and even more preferably 1000 to 5000. Below the lower limit of the above range, the amount of volatilization is high, making it difficult to adjust the solid content during prepreg preparation, and above the upper limit of the above range, compatibility with other curable resins deteriorates. Generally, in the case of compounds containing heteroatoms such as oxygen and nitrogen, such as bismaleimide and polymaleimide, it is difficult to ensure compatibility with low-polarity compounds such as compounds composed mainly of hydrocarbons or compounds composed only of hydrocarbons, due to their polarity. On the other hand, the maleimide resin, cyanate ester resin and compound (1) of this embodiment do not have a framework design that actively incorporates heteroatoms such as oxygen and nitrogen, and therefore exhibit excellent compatibility with materials that have low polarity and low dielectric loss tangent, as well as compounds composed only of hydrocarbons.

[0150] [Polystyrene and its modified forms] Polystyrene and its modified products are compounds that have polystyrene or a structure derived from polystyrene within their molecule. Examples of polystyrene and its modified products include polystyrene, styrene-2-isopropenyl-2-oxazoline copolymer (Epocross RPS-1005, RP-61, both manufactured by Nippon Shokubai Co., Ltd.), SEP (styrene-ethylene-propylene copolymer: Septon 1020, manufactured by Kuraray Co., Ltd.), SEPS (styrene-ethylene-propylene-styrene copolymer: Septon 2002, Septon 2004F, Septon 2005, Septon 2006, Septon 2063, Septon 2104, all manufactured by Kuraray Co., Ltd.), SEEPS (styrene-ethylene / ethylene-propylene-styrene block copolymer: Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099, all manufactured by Kuraray Co., Ltd.), and SEBS (styrene-ethylene-butylene-styrene). Examples of block copolymers include Septon 8004, Septon 8006, Septon 8007L (all manufactured by Kuraray Co., Ltd.), SEEPS-OH (a compound having hydroxyl groups at the ends of styrene-ethylene / ethylene-propylene-styrene block copolymers: Septon HG252, manufactured by Kuraray Co., Ltd.), SIS (styrene-isoprene-styrene block copolymers: Septon 5125, Septon 5127, both manufactured by Kuraray Co., Ltd.), hydrogenated SIS (hydrogenated styrene-isoprene-styrene block copolymers: Hybrar 7125F, Hybrar 7311F, both manufactured by Kuraray Co., Ltd.), SIBS (styrene-isobutylene-styrene block copolymers: SIBSTAR073T, SIBSTAR102T, SIBSTAR103T (all manufactured by Kaneka Corporation), Septon V9827 (manufactured by Kuraray Co., Ltd.)), but are not limited to these. Furthermore, these can be used individually or in combination of multiple types. Polystyrene and its modified products are preferable to be those without unsaturated bonds, as they have higher heat resistance and are less susceptible to oxidative degradation. Furthermore, while there are no particular restrictions on the weight-average molecular weight of polystyrene and its modified products as long as it is 10,000 or more, if it is too high, the compatibility with polyphenylene ether compounds, as well as low molecular weight components with a weight-average molecular weight of about 50 to 1,000 and oligomer components with a weight-average molecular weight of about 1,000 to 5,000 deteriorates, making it difficult to ensure mixing and solvent stability. Therefore, it is preferable that the molecular weight be around 10,000 to 300,000.

[0151] [Polyethylene and its modified forms] Polyethylene and its modified products refer to polyethylene or compounds having a polyethylene-derived structure within their molecules. Examples of polyethylene and its modified products include, but are not limited to, ethylene-propylene copolymers, ethylene-styrene copolymers, ethylene-propylene-ethylidene norbornene copolymers (Mitsui Chemicals EBT: K-8370EM, K-9330M, etc.), ethylene-propylene-vinyl norbornene copolymers (Mitsui Chemicals VNB-EPT: PX-006M, PX-008M, PX-009M, etc.), ethylene-vinyl alcohol copolymers, and ethylene-vinyl acetate copolymers. From the viewpoint of improving heat resistance, it is preferable to use ethylene-propylene-ethylidene norbornene copolymers or ethylene-propylene-vinyl norbornene copolymers that contain a crosslinkable structure. Furthermore, these may be used individually or in combination of multiple types. While there are no particular restrictions on the weight-average molecular weight of polyethylene and its modified products as long as it is 10,000 or more, if it is too high, the compatibility with polyphenylene ether compounds, as well as low molecular weight components with a weight-average molecular weight of about 50 to 1,000 and oligomer components with a weight-average molecular weight of about 1,000 to 5,000 deteriorates, making it difficult to ensure mixing and solvent stability. Therefore, it is preferable that the molecular weight be around 10,000 to 300,000.

[0152] [Benzoxazine compounds] As the benzoxazine compound, any compound having two or more dihydrobenzoxazine rings in one molecule can be used, and any generally known compound can be used. For example, bisphenol A type benzoxazine BA-BXZ (manufactured by Konishi Chemical Co., Ltd.), bisphenol F type benzoxazine BF-BXZ (manufactured by Konishi Chemical Co., Ltd.), bisphenol S type benzoxazine BS-BXZ (manufactured by Konishi Chemical Co., Ltd.), phenolphthalein type benzoxazine, etc. are examples, but there are no particular limitations. These benzoxazine compounds can be used individually or in appropriate mixtures of two or more.

[0153] [Compounds containing ethylenically unsaturated bonds] A compound having an ethylenically unsaturated bond is a compound that has one or more ethylenically unsaturated bonds in its molecule that can be polymerized by heat or light, regardless of whether a polymerization initiator is used or not. Compounds containing an ethylenically unsaturated bond are compounds other than the maleimide resin described above, the maleimide resin of this embodiment, polybutadiene and its modified products, and the curable resin represented by formula (1). Styryl groups and methacrylic groups are preferred as the ethylenically unsaturated bond, with styryl groups being particularly preferred. The ethylenically unsaturated bond equivalent is preferably 50 g / eq. to 3000 g / eq., more preferably 75 g / eq. to 2500 g / eq., even more preferably 90 g / eq. to 2000 g / eq., and particularly preferably 100 g / eq. to 1500 g / eq. Compounds containing ethylenically unsaturated bonds may be copolymerized with the olefin compounds listed below. Examples include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, and 12-ethyl-1-tetradecene. Examples of cyclic olefins with 5 to 20 carbon atoms include ethylidene norbornene, norbornene, and cyclopentene. Examples of compounds having ethylenically unsaturated bonds include the reaction products of the phenol resin and halogenated compounds having ethylenically unsaturated bonds (chloromethylstyrene, allyl chloride, methallyl chloride, acrylate chloride, methacrylate chloride, etc.), and phenols having ethylenically unsaturated bonds (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) and halogenated compounds (1,4-bis(chloromethyl)ben Reaction products of zen, 4,4'-bis(chloromethyl)biphenyl, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuryl chloride, etc., reaction products of epoxy resins or alcohols with (meth)acrylic acids (acrylic acid, methacrylic acid, etc.) and acid-modified products thereof, poly(arylene ether) polymers (HC-G0037, HC-G0024, HC-G0030, HC-G0038, all manufactured by JSR Corporation. These are pyridazine, pyrimidine or (May contain monomer units containing a pyrazine group.) Reaction products of fluorenes or indenes with halogenated compounds having ethylenically unsaturated bonds (chloromethylstyrene, allyl chloride, metharyl chloride, acrylate chloride, methacrylate chloride, etc.), compounds described in Japanese Patent No. 6951829, copolymers containing divinylbenzene as a constituent unit (ODV-XET(X3), ODV-XET(X4), ODV-XET(X5), all manufactured by Nippon Steel Chemical & Material Co., Ltd.), styrene, vinylitol Examples include, but are not limited to, ethyl vinylbenzene, vinyl naphthalene, vinyl biphenyl, vinyl fluorene, divinylbenzene, divinyl naphthalene, divinyl biphenyl, divinyl fluorene, BVPM (bis(vinylphenyl)methane), BVPE (bis(vinylphenyl)ethane), BVPH (bis(vinylphenyl)hexane), trivinylcyclohexane, and thermosetting cycloolefin copolymers (Mitsui Chemicals: GigaFreak, Zeon Corporation: TU-01A). These can be used individually or in combination.

[0154] The curable resin composition of this embodiment is obtained by preparing the above components in predetermined proportions, pre-curing at 130-180°C for 30-500 seconds, and then post-curing at 150-200°C for 2-15 hours to allow the curing reaction to proceed sufficiently and obtain the cured product of this embodiment. Alternatively, the components of the curable resin composition can be uniformly dispersed or dissolved in a solvent, and then cured after removing the solvent.

[0155] The method for preparing the curable resin composition of this embodiment is not particularly limited, but the components may be uniformly mixed or prepolymerized. For example, a mixture of the maleimide resin of this embodiment and the curable resin represented by formula (1) may be prepolymerized by heating in the presence or absence of a curing accelerator and polymerization initiator, and in the presence or absence of a solvent. Similarly, compounds such as amine compounds, compounds having ethylenically unsaturated bonds, maleimide resin, cyanate ester compounds, polybutadiene and its modified products, polystyrene and its modified products, inorganic fillers, and other additives may be added and prepolymerized. Mixing or prepolymerizing the components may be done using, for example, an extruder, kneader, or roll in the absence of a solvent, and using a reaction vessel with a stirring device in the presence of a solvent.

[0156] For uniform mixing, the resin composition is kneaded using equipment such as a kneader, roll, or planetary mixer at a temperature in the range of 50 to 100°C. After pulverization, the resulting resin composition can be molded into cylindrical tablets using a molding machine such as a tablet machine, or into granular powder or powdered molded bodies. Alternatively, these compositions can be melted on a surface support and molded into sheets with a thickness of 0.05 mm to 10 mm to produce curable resin composition molded bodies. The resulting molded bodies are non-sticky at 0 to 20°C and maintain almost no decrease in fluidity or curability even after storage at -25 to 0°C for more than a week. The resulting molded body can be molded into a hardened product using a transfer molding machine or a compression molding machine.

[0157] The curable resin composition of this embodiment can also be converted into a varnish-like composition (hereinafter simply referred to as varnish) by adding an organic solvent. The curable resin composition of this embodiment can be dissolved in a solvent such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, or N-methylpyrrolidone as needed to form a varnish, which can then be impregnated into a substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, or paper, and the resulting prepreg, which is heat-dried, can be hot-press-molded to obtain a cured product of the curable resin composition of this embodiment. In this case, the solvent used is in an amount that accounts for 10 to 70% by weight, preferably 15 to 70% by weight, of the mixture of the curable resin composition of this embodiment and the solvent. If it is a liquid composition, a cured product of the curable resin containing carbon fibers can also be obtained directly, for example, by the RTM method.

[0158] Furthermore, the curable resin composition of this embodiment can also be used as a modifier for film-type compositions. Specifically, it can be used to improve flexibility and other properties in the B-stage. Such a film-type resin composition can be obtained as a sheet-like adhesive by applying the curable resin composition of this embodiment as a curable resin composition varnish onto a release film, removing the solvent under heating, and then performing B-stage formation. This sheet-like adhesive can be used as an interlayer insulating layer in multilayer substrates and the like.

[0159] The curable resin composition of this embodiment can also be heated and melted to reduce viscosity and impregnate reinforcing fibers such as glass fibers, carbon fibers, polyester fibers, polyamide fibers, and alumina fibers to obtain a prepreg. Specific examples include, but are not limited to, glass fibers such as E glass cloth, D glass cloth, S glass cloth, Q glass cloth, spherical glass cloth, NE glass cloth, and T glass cloth, as well as inorganic fibers other than glass, and organic fibers such as poly(p-phenylene terephthalamide) (Kevlar®, manufactured by DuPont), fully aromatic polyamide, polyester, poly(p-phenylene benzoxazole), polyimide, and carbon fiber. The shape of the substrate is not particularly limited, but examples include woven fabrics, nonwoven fabrics, rovings, and chopped strand mats. As for the weaving method of the woven fabric, plain weave, twill weave, etc., are known, and these can be appropriately selected and used depending on the intended application and performance. Furthermore, glass woven fabrics that have been opened or surface-treated with silane coupling agents are preferably used. The thickness of the base material is not particularly limited, but is preferably about 0.01 to 0.4 mm. Alternatively, a prepreg can be obtained by impregnating reinforcing fibers with the above varnish and then heating and drying them.

[0160] Furthermore, laminates can also be manufactured using the above-mentioned prepregs. The laminate is not particularly limited as long as it comprises one or more prepregs, and may have any other layers. The method for manufacturing the laminate is not particularly limited and can be any generally known method as appropriate. For example, when forming a metal foil laminate, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, an autoclave molding machine, etc., can be used, and a laminate can be obtained by laminating the above-mentioned prepregs together and heating and pressing them. At this time, the heating temperature is not particularly limited, but 65 to 300°C is preferred, and 120 to 270°C is more preferred. The pressurizing pressure is not particularly limited, but if the pressurizing pressure is too high it is difficult to adjust the solid content of the resin in the laminate and the quality is not stable, and if the pressurizing pressure is too low it becomes difficult to form air bubbles and the adhesion between layers is poor, so 2.0 to 5.0 MPa is preferred, and 2.5 to 4.0 MPa is more preferred. The laminate of this embodiment can be suitably used as a metal foil laminate described later by comprising a layer made of metal foil. By cutting the above prepreg into the desired shape, laminating it with copper foil or other materials as needed, and then applying pressure to the laminate using methods such as press molding, autoclave molding, or sheet winding molding while heating and curing a curable resin composition, electrical and electronic laminates (printed wiring boards) and carbon fiber reinforced materials can be obtained.

[0161] The curable resin composition of this embodiment can also be made into a resin sheet. One method for obtaining a resin sheet from the curable resin composition of this embodiment is to apply the curable resin composition onto a support film (support), dry it, and then form a resin composition layer on the support film. When using the curable resin composition of this embodiment to make a resin sheet, it is important that the film softens at the lamination temperature conditions (70°C to 140°C) in the vacuum lamination method and exhibits fluidity (resin flow) that allows for simultaneous lamination of the circuit board and resin filling of via holes or through holes present in the circuit board. It is preferable to blend the above components in such a way as to exhibit such characteristics. Furthermore, in order to prevent phenomena such as locally different characteristic values ​​caused by phase separation from occurring in the resulting resin sheet or circuit board (copper-clad laminate, etc.), uniformity of appearance is required to ensure that a certain level of performance is achieved in any desired area.

[0162] Here, the diameter of the through-holes in the circuit board is 0.1 to 0.5 mm, and the depth is 0.1 to 1.2 mm. It is preferable to be able to fill the holes with resin within this range. When laminating both sides of the circuit board, it is desirable that the through-holes be filled to about half their extent.

[0163] A specific method for manufacturing the above-mentioned resin sheet is to prepare a varnished resin composition by incorporating an organic solvent, apply the varnished resin composition to the surface of a support film (Y), and then dry the organic solvent by heating or blowing hot air to form a resin composition layer (X).

[0164] The organic solvents used here preferably include ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; and it is preferable to use them in a proportion that results in a non-volatile content of 30 to 60% by mass.

[0165] Furthermore, the thickness of the formed resin composition layer (X) must be greater than or equal to the thickness of the conductor layer. Since the thickness of the conductor layer of the circuit board is in the range of 5 to 70 μm, it is preferable that the thickness of the resin composition layer (X) be 10 to 100 μm. In this embodiment, the resin composition layer (X) may be protected by a protective film, which will be described later. By protecting it with a protective film, it is possible to prevent dust and other debris from adhering to the surface of the resin composition layer and to prevent scratches.

[0166] The above-mentioned support film and protective film can be made of polyolefins such as polyethylene, polypropylene, and polyvinyl chloride, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polycarbonate, polyimide, and also release paper, copper foil, aluminum foil, and other metal foils. The support film and protective film may be treated with a mat treatment, corona treatment, or release treatment. The thickness of the support film is not particularly limited, but is 10 to 150 μm, preferably in the range of 25 to 50 μm. The thickness of the protective film is preferably 1 to 40 μm.

[0167] The support film (Y) described above is peeled off after lamination to the circuit board or after an insulating layer has been formed by heat curing. If the support film (Y) is peeled off after the resin composition layer constituting the resin sheet has been heat cured, it is possible to prevent the adhesion of dust and other debris during the curing process. When peeling off after curing, the support film is treated with a release agent beforehand.

[0168] Furthermore, a multilayer printed circuit board can be manufactured from the resin sheet obtained as described above. For example, if the resin composition layer (X) is protected by a protective film, these are removed, and then the resin composition layer (X) is laminated to one or both sides of the circuit board so that it is in direct contact with the circuit board, for example, by a vacuum lamination method. The lamination method may be batch or continuous on a roll. If necessary, the resin sheet and circuit board may be heated (preheated) before lamination. The lamination conditions are preferably a pressure temperature (lamination temperature) of 70 to 140°C and a pressure of 1 to 11 kgf / cm². 2 (9.8 × 10 4 ~107.9×10 4 N / m 2 It is preferable to use this method, and it is preferable to laminate under reduced pressure of 20 mmHg (26.7 hPa) or less.

[0169] Furthermore, semiconductor devices can be manufactured using the curable resin composition of this embodiment. Examples of semiconductor devices include DIP (Dual In-Line Package), QFP (Quad Flat Package), BGA (Ball Grid Array), CSP (Chip Size Package), SOP (Small Outline Package), TSOP (Thin Small Outline Package), and TQFP (Thin Quad Flat Package).

[0170] The curable resin composition and its cured product according to this embodiment can be used in a wide range of fields. Specifically, it can be used in various applications such as molding materials, adhesives, composite materials, and paints. Because the cured product of the curable resin composition described in this embodiment exhibits excellent heat resistance and dielectric properties, it is suitably used in electrical and electronic components such as encapsulants for semiconductor devices, encapsulants for liquid crystal display devices, encapsulants for organic EL devices, laminates (printed wiring boards, BGA substrates, build-up substrates, etc.), composite materials for lightweight, high-strength structural materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, and 3D printing. [Examples]

[0171] Next, the present invention will be described in more detail with reference to examples. Hereinafter, unless otherwise specified, parts refer to parts by mass. However, the present invention is not limited to these examples.

[0172] The various analytical methods used in the examples are described below.

[0173] <High-Performance Liquid Chromatography (HP-LC)> HP-LC: Liquid delivery unit (LC-20AB), online degasser (DGU-20A3), autosampler (SIL-20A), column oven (CTO-20A), system controller (CBM-20A), absorbance detector (SPD-M20A) (all manufactured by Shimadzu Corporation) Column: ODS-2 (manufactured by GL Sciences Co., Ltd.) Linking eluent: tetrahydrofuran:water = 3:1 (no gradient) Flow rate: 0.5ml / min. Column temperature: 40℃ Detection: PDA (Photodiode Array Detector)

[0174] [Synthesis Example 1] A flask equipped with a thermometer, condenser, and stirrer was purged with nitrogen, and 200 parts of DMSO, 33.3 parts of fluorene, and 24 parts of sodium hydroxide were added and stirred at 35°C for 30 minutes. Then, while maintaining the internal temperature below 40°C, 58.0 parts of CMS-P (AGC Seimi Chemical Co., Ltd., a mixture of 4-chloromethylstyrene and 3-chloromethylstyrene, 4-chloromethylstyrene:3-chloromethylstyrene = 1:1 (mol ratio), purity 95.59 wt) was added dropwise over 1 hour and reacted at 40°C for 20 hours. 200 parts of methanol and 100 parts of water were added to crystallize, and the crystals were collected by filtration. The collected crystals were dissolved in 200 parts of toluene, and the organic layer was washed five times with 100 parts of water. The obtained organic layer was concentrated to obtain 56.4 parts of olefin compound (O-1). The HP-LC chart of the obtained olefin compound (O-1) is shown in Figure 1. The olefin equivalent calculated from the structural formula was 199 g / eq.

[0175] [ka]

[0176] • Maleimide resin MIR-3000 (manufactured by Nippon Kayaku Co., Ltd.; maleimide equivalent was measured by the method described in Japanese Patent Publication No. 2020-187012 and was 302 g / eq.; the softening point was 115.5°C and the viscosity at 150°C was 5.3 Pa·s.) • Cyanate ester resin CYTESTER TA (manufactured by Mitsubishi Gas Co., Ltd., bisphenol A type cyanate ester resin) • Polyphenylene ether compounds OPE-2St 2200 (manufactured by Mitsubishi Gas Chemical Company, Inc.) • Curing accelerator 18% Octope Zn (manufactured by Hope Pharmaceutical Co., Ltd.)

[0177] [Example 1, Comparative Example 1] [Preparation of cured product] Each material was measured out in the proportions (parts by mass) shown in Table 1, and toluene was added to achieve a resin solids content of 50% by mass. Varnish was then prepared by mixing. The varnish was heated in a vacuum dryer at 80°C for 30 minutes and then at 100°C for 30 minutes to prepare a curable resin composition. The obtained curable resin composition was sandwiched between copper foils and cured under vacuum at a pressure of 1 MPa at 200°C for 2 hours. Comparative Example 1 was cured at 220°C for 2 hours. The results are shown in Table 1.

[0178] <Dielectric constant test / Dielectric loss tangent test> Tests were conducted using a 10GHz cavity resonator manufactured by AET Co., Ltd. at 25°C using the cavity resonator perturbation method. The sample size was 2.5 mm wide x 50 mm long with a thickness of 0.25 mm.

[0179] [Table 1]

[0180] As is clear from Table 1, Example 1 was confirmed to exhibit good dielectric properties. [Industrial applicability]

[0181] The curable resin composition of the present invention is suitable for use in semiconductor encapsulants, printed circuit boards, build-up laminates, optical waveguide devices and other electrical and electronic components, redistribution layers, lightweight high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, and 3D printing applications.

[0182] [Note] As described above, this embodiment includes the following disclosures. [1] A curable resin composition comprising a maleimide resin having a maleimide equivalent of 150 g / eq. to 1200 g / eq. and containing at least one maleimide group in its molecule, a cyanate ester resin, and a curable resin represented by the following formula (1).

[0183] [ka]

[0184] (In equation (1), the multiple R1, R2, l, and m each exist independently. R1 represents a hydrocarbon group with 1 to 50 carbon atoms. R2 represents a hydrocarbon group with 1 to 10 carbon atoms. l and m represent integers from 0 to 4.) [2] The curable resin composition according to [1], wherein the maleimide resin is a maleimide resin represented by the following formula (2) and / or a maleimide resin represented by the following formula (3).

[0185] [ka]

[0186] (In formulas (2) and (3), the multiple X, R3, and p each exist independently, with X representing a hydrocarbon group having 1 to 25 carbon atoms, R3 representing an alkyl group having 1 to 20 carbon atoms, or an aromatic group having 1 to 20 carbon atoms that may have substituents, and p being an integer from 0 to 4. n represents the number of repetitions, and the average value of n is 1 <n ave <10. Equation (3) has structural units (a) and (b), (a) and (b) are joined by *, and the repeating positions may be random. k and o represent the number of repeats, and the average value of k is 1 ≤ k. ave ≤ 1000, the mean of o is 1 ≤ o ave (≤ 1000.) [3] A curable resin composition according to [1] or [2], wherein the aforementioned X is represented by the following formulas (1-a) to (1-f).

[0187] [ka]

[0188] (In formulas (1-a) to (1-f), the multiple R4, R5, q, and t each exist independently. R4 represents an alkyl group having 1 to 20 carbon atoms, or an aromatic group having 1 to 20 carbon atoms that may have substituents. R5 represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aromatic group having 1 to 20 carbon atoms that may have substituents. q is an integer from 0 to 4, and t is an integer from 0 to 3. r is the number of repetitions, and the average value of r is 1.) <r ave <10. [4] A curable resin composition according to any one of [1] to [3], wherein the content of the curable resin represented by formula (1) is 5% to 50% by mass of the total amount of the curable resin composition. [5] A curable resin composition according to any one of [1] to [4], further comprising a polyphenylene ether compound. [6] The curable resin composition according to any one of [1] to [5], wherein the curable resin represented by formula (1) is a reaction product of a mixture containing a compound represented by the following formula (A) and a compound represented by the following formula (B), and the mixture contains a compound in which the orientation between the vinyl group and the halomethyl group is at the meta position and a compound in which the orientation between the vinyl group and the halomethyl group is at the para position.

[0189] [ka]

[0190] (In formulas (A) and (B), the multiple R1, R2, m, and l each exist independently. In formula (A), R1 represents a hydrocarbon group with 1 to 50 carbon atoms, and m represents an integer from 0 to 4. In formula (B), R2 represents a hydrocarbon group with 1 to 10 carbon atoms, l is an integer from 0 to 4, and W represents a halogen atom.) [7] Furthermore, the curable resin composition according to any one of [1] to [6] contains at least one selected from a curing accelerator, a polymerization initiator, an epoxy resin, an active ester compound, a phenolic resin, an amine resin, an isocyanate resin, a polyamide resin, a maleimide resin, a polyimide resin, a polybutadiene and modified thereof, polystyrene and modified thereof, polyethylene and modified thereof, a benzoxazine compound, and a compound having an ethylenically unsaturated bond. [8] A cured product obtained by curing any of the curable resin compositions described in [1] to [7].

Claims

1. A curable resin composition comprising a maleimide resin having a maleimide equivalent of 150 g / eq. to 1200 g / eq. and containing at least one maleimide group in its molecule, a cyanate ester resin, and a curable resin represented by the following formula (1). 【Chemistry 1】 (In equation (1), there are multiple R １ , R ２ l and m exist independently of each other, R １ R represents a hydrocarbon group with 1 to 50 carbon atoms. ２ (where l and m represent integers from 0 to 4.)

2. The curable resin composition according to claim 1, wherein the maleimide resin is a maleimide resin represented by the following formula (2) and / or a maleimide resin represented by the following formula (3). 【Chemistry 2】 (In formulas (2) and (3), a plurality of X and R ３ and p are each independently present, and X represents a hydrocarbon group having 1 to 25 carbon atoms. R ３ represents an alkyl group having 1 to 20 carbon atoms, or an aromatic group having 1 to 20 carbon atoms which may have a substituent, p is an integer of 0 to 4, n represents the number of repetitions, and the average value of n satisfies 1 < n ａｖｅ < 10. Formula (3) has structural units (a) and (b), (a) and (b) are each bonded via *, and the repetition positions may be random. k and o represent the number of repetitions, and the average value of k satisfies 1 ≤ k ａｖｅ ≤ 1000, and the average value of o satisfies 1 ≤ o ａｖｅ ≤ 1000. )

3. The curable resin composition according to claim 1, wherein the aforementioned X is represented by the following formulas (1-a) to (1-f). 【Transformation 3】 (In equations (1-a) to (1-f), there are multiple R ４ , R ５ q and t exist independently of each other, R ４ R represents an alkyl group having 1 to 20 carbon atoms, or an aromatic group having 1 to 20 carbon atoms which may have substituents. ５ represents a hydrogen atom, a C1-C20 alkyl group, or an aromatic group having C1-C20 which may have substituents. q is an integer from 0 to 4, and t is an integer from 0 to 3. r is the number of repetitions, and the average value of r is 1 < r ａｖｅ (It is 10.)

4. The curable resin composition according to claim 1, wherein the content of the curable resin represented by formula (1) is 5% by mass to 50% by mass of the total amount of the curable resin composition.

5. The curable resin composition according to claim 1, further comprising a polyphenylene ether compound.

6. The curable resin composition according to claim 1, wherein the curable resin represented by formula (1) is a reaction product of a mixture containing a compound represented by the following formula (A) and a compound represented by the following formula (B), and the mixture contains a compound in formula (B) in which the orientation between the vinyl group and the halomethyl group is at the meta position and a compound in which the orientation between the vinyl group and the halomethyl group is at the para position. 【Chemistry 4】 (In equations (A) and (B), there are multiple R １ , R ２ m and l exist independently of each other, and in equation (A), R １ R represents a hydrocarbon group having 1 to 50 carbon atoms, and m represents an integer from 0 to 4. In formula (B), R ２ (where l is a hydrocarbon group with 1 to 10 carbon atoms, l is an integer from 0 to 4, and W represents a halogen atom.)

7. The curable resin composition according to claim 1, further comprising at least one selected from a curing accelerator, polymerization initiator, epoxy resin, active ester compound, phenol resin, amine resin, isocyanate resin, polyamide resin, maleimide resin, polyimide resin, polybutadiene and modified thereof, polystyrene and modified thereof, polyethylene and modified thereof, benzoxazine compound, and compound having an ethylenically unsaturated bond.

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

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