Curable resin composition and cured product thereof

Abstract

The present invention provides: a curable resin composition having excellent heat resistance and low dielectric properties; and a cured product of the curable resin composition.　This curable resin composition comprises: a maleimide resin that has a maleimide equivalent of 250-1000 g / eq. and has one or more structures represented by formula (1) in the molecule thereof; and a copolymer containing ethylene, styrene, and divinylbenzene. (In the formula (1), Ar is a substituted or unsubstituted aryl group.)

Description

Curable resin composition and its cured product

[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 lightweight, high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, and in 3D printing applications.

[0002] In recent years, the required characteristics of laminates on which electrical and electronic components are mounted 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, there is a need for the development of thermosetting resins or compositions containing thermosetting resins that maintain heat resistance while exhibiting excellent low dielectric properties.

[0004] Against this backdrop, the development of thermosetting resins with excellent low dielectric properties and compositions containing thermosetting resins is being considered. For example, Patent Document 1 proposes a composition containing maleimide resin and propenyl group-containing phenol resin. However, on the other hand, phenolic hydroxyl groups that do not participate in the reaction remain during the curing reaction, so the electrical properties are not sufficient. Patent Document 2 discloses an allyl ether resin in which hydroxyl groups are substituted with allyl groups. However, it has been shown that a Claisen rearrangement occurs at 190°C, and at 200°C, which is the typical molding temperature for substrates, phenolic hydroxyl groups that do not contribute to the curing reaction are generated, so the electrical properties cannot be satisfied. Furthermore, Patent Document 3 proposes a composition having a monofunctional maleimide resin and an olefin-containing polymer with the aim of providing a resin composition that can obtain a cured product with low dielectric properties and high heat resistance, but the electrical properties are not sufficient.

[0005] Signal Loss Factors in High-Speed ​​Signal Transmission on Printed Circuit Boards (Mitsui Mining & Smelting Co., Ltd.) 29th Spring Conference of the Japan Society for Electronics Packaging 16P1-17

[0006] Japanese Patent Publication No. 04-359911, International Publication No. 2016 / 002704, Japanese Patent No. 7190649

[0007] Regarding heat resistance, it is not just the glass transition temperature (Tg) of the cured material that matters, but also how the elastic modulus changes from room temperature to high temperatures. If the elastic modulus changes in multiple stages from room temperature to high temperatures, stress will accumulate at each stage, which may cause defects such as delamination of the copper foil or prepreg on the substrate, or cracks in the substrate. In other words, the development of resin materials and resin compositions that reduce the number of inflection points in the elastic modulus is also desired.

[0008] This invention has been made in view of the above circumstances, and aims to provide a curable resin composition and a cured product thereof that are excellent in heat resistance and low dielectric properties.

[0009] In other words, the present invention relates to the following [1] to [6]. In this application, "(numerical value 1) to (numerical value 2)" indicates that upper and lower limits are included. [1] A curable resin composition containing a maleimide resin having a maleimide equivalent of 250 g / eq. to 1000 g / eq. and having one or more structures represented by the following formula (1) in its molecule, and a copolymer containing ethylene, styrene, and divinylbenzene.

[0010]

[0011] (In formula (1), Ar is a substituted or unsubstituted aryl group.)

[0012] [2] The curable resin composition according to paragraph [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).

[0013]

[0014] (In equations (2) and (3), there are multiple X and R １ p exists independently, and X represents a hydrocarbon group with 1 to 25 carbon atoms. １ represents 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 is an integer from 0 to 4. n is the average number of repeats, where 1 < n < 10. Formula (3) has structural units (a) and (b), where (a) and (b) are linked by *, and the repeating positions may be random. m and o are the average number of repeats, where 1 ≤ m ≤ 1000 and 1 ≤ o ≤ 1000.

[0015] [3] The curable resin composition according to item [2] above, wherein X is one of the structures represented by the following formulas (1-a) to (1-f).

[0016]

[0017] (In equations (1-a) to (1-f), there are multiple R ２ , R ３ q and t exist independently of each other, R ２ 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. ３represents an alkyl group having 1 to 20 carbon atoms, or an aromatic group having 1 to 20 carbon atoms which may have substituents. q is an integer from 0 to 4, and t is an integer from 0 to 3. r is the average value of the number of repeats, where 1 < r < 10. * represents the bond position.) [4] The curable resin composition according to any one of the preceding paragraphs [1] to [3], wherein the content of the copolymer is 5 to 50% by mass of the total amount of the curable resin composition. [5] The curable resin composition according to any one of the preceding paragraphs [1] to [4], further comprising a curing accelerator, a polymerization initiator, an epoxy resin, an active ester compound, a phenol resin, a polyphenylene ether compound, an amine resin, a compound having an ethylenically unsaturated bond, an isocyanate resin, a polyamide resin, a maleimide resin other than the maleimide resin, a cyanate ester resin, a polyimide resin, polybutadiene and a modified product thereof, polystyrene and a modified product thereof, polyethylene and a modified product thereof, and a benzoxazine compound. [6] A cured product obtained by curing any one of the curable resin compositions described in item [1] to [5] above.

[0018] According to the present invention, it is possible to provide a curable resin composition and a cured product thereof that are excellent in heat resistance and low dielectric properties.

[0019] The GPC chart for synthesis example 1 is shown. The GPC chart for synthesis example 2 is shown. The GPC chart for synthesis example 3 is shown.

[0020] The embodiments of the present invention (hereinafter also referred to as "this embodiment") will be described in more detail below.

[0021] The curable resin composition of this embodiment contains a maleimide resin (hereinafter also referred to as the maleimide resin of this embodiment) having a maleimide equivalent of 250 g / eq. to 1000 g / eq. and having one or more structures represented by the following formula (1) in its molecule, and a copolymer containing ethylene, styrene, and divinylbenzene (hereinafter also referred to as the copolymer of this embodiment).

[0022]

[0023] In formula (1), Ar is a substituted or unsubstituted aryl group. Examples of aryl groups include phenyl, naphthyl, anthryl, biphenylyl, and terphenyl groups, with phenyl being preferred. Examples of substituents include C1 to C20 alkyl groups or C1 to C20 aromatic groups which may have substituents, and the alkyl group is preferably C1 to C5, and more preferably a methyl group.

[0024] The maleimide resin of this embodiment is not particularly limited as long as it has one or more structures of formula (1) in its molecule and a maleimide equivalent of 250 to 1000 g / eq. Here, maleimide equivalent is the mass of a compound containing one equivalent of maleimide groups. For example, if a maleimide resin with a molecular weight of 250 has one maleimide group attached, the functional group equivalent will be 250 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 molecule has two or more maleimide groups, and it is particularly preferable that the maleimide resin is represented by the following formula (2) or the following formula (3). These may be used individually or in combination.

[0025]

[0026] In equations (2) and (3) above, there are multiple X and R. １ p exists independently, and X represents a hydrocarbon group having 1 to 25 carbon atoms, preferably one of the structures represented by the following formulas (1-a) to (1-f). １represents 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, more preferably a methyl group. p is an integer of 0 to 4. n is an average value of the number of repetitions, and 1 < n < 10. Formula (3) has structural units of (a) and (b), and (a) and (b) are each bonded by *, and the repeating positions may be random. m and o are average values of the number of repetitions. Usually, 1 ≤ m ≤ 1000, preferably 2 ≤ m ≤ 750, and more preferably 3 ≤ m ≤ 500. Usually, 1 ≤ o ≤ 1000, preferably 1 ≤ o ≤ 500, more preferably 1.1 ≤ o ≤ 100, and particularly preferably 1.1 ≤ o ≤ 20. Since the values of m and o are derived from the styrene-maleic acid copolymer used as a raw material, they can be determined from its acid value. The preferred range of the molecular weight of the styrene-maleic acid copolymer used as a raw material (weight average molecular weight (Mw) determined by measurement of gel permeation chromatography (GPC)) 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 evaporation step.

[0027]

[0028] In Formulas (1-a) to (1-f), when there are a plurality of R's ２ , R ３ , q, and t each exist independently, and R ２ 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, and 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. The alkyl group preferably has 1 to 5 carbon atoms, more preferably a methyl group. q is an integer of 0 to 4, and t is an integer of 0 to 3. r is an average value of the number of repetitions, and 1 < r < 10. * represents a bonding position.

[0029] In the above formula (2), the value of n can be determined by measuring the number average molecular weight of the maleimide resin by gel permeation chromatography (GPC, detector: RI), or can be calculated from the area ratio of each separated peak. In the above formula (1), when n = 1, the solubility in the solvent is low, and when n is 10 or more, the flowability during molding deteriorates, and the properties of the cured product cannot be fully exhibited.

[0030] The maleimide equivalent of the maleimide resin of this embodiment is preferably 250 to 1000 g / eq., more preferably 275 to 950 g / eq., and particularly preferably 300 to 900 g / eq. Here, the maleimide equivalent is the value obtained by dividing the molecular weight of the maleimide resin by the number of maleimide groups. The maleimide equivalent of the maleimide resin can be measured, for example, by the measurement method described in JP-A-2020-187012. Also, when the maleimide equivalent can be calculated from the structural formula and the number of functional groups, that value may be used. If the maleimide equivalent is less than 250 g / eq., the polarity becomes high, the compatibility with the copolymer deteriorates, and a cured product cannot be obtained or, if obtained, becomes brittle. On the other hand, if the maleimide equivalent is more than 1000 g / eq., there is a risk of deterioration in heat resistance. When the maleimide equivalent is within the above range, a cured product can be obtained without deteriorating the heat resistance of the obtained cured product.

[0031] The softening point of the maleimide resin of this embodiment is preferably 50 to 200°C, more preferably 60 to 195°C, still more preferably 70 to 190°C, and particularly preferably 80 to 185°C. Also, the melt viscosity at 150°C is 0.05 to 100 Pa·s, preferably 0.1 to 40 Pa·s.

[0032] Hereinafter, the production method of the maleimide resin represented by the above formula (2) will be described, but it is not limited to this production method.

[0033] For the maleimide resin represented by the above formula (2), an aromatic amine resin can be used as a precursor. For example, when X in the above formula (2) is (1 - c), R ３When it is hydrogen, the following formula (4) is the precursor aromatic amine resin, X in the above formula (2) is (1-b), and R ３ When is a methyl group, the following formula (5) becomes the precursor aromatic amine resin.

[0034]

[0035] In the above formulas (4) and (5), R １ , R ２ , p, q, and n have the same meanings as in the above formula (2).

[0036] The method for obtaining the aromatic amine resin represented by the above formula (4) is not particularly limited. For example, Japanese Patent Application Laid-Open No. 3-100016 and Japanese Patent Publication No. 8-16151 describe the reaction of anilines with dihalogenomethyl compounds or dialkoxymethyl compounds. By adopting a method similar to these, aniline is reacted with bis(halogenomethyl)biphenyls or bis(alkoxymethyl)biphenyls to obtain the aromatic amine resin represented by the above formula (4).

[0037] Examples of the bis(halogenomethyl)biphenyls or bis(alkoxymethyl)biphenyls 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, 4,4'-di-tert-butoxymethylbiphenyl, and the like. These may be used alone or in combination of two or more. The amount of bis(halogenomethyl)biphenyls or bis(alkoxymethyl)biphenyls used is preferably 0.05 to 0.8 mol, more preferably 0.1 to 0.6 mol, per 1 mol of aniline used.

[0038] 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 to 100°C, more preferably 50 to 80°C, over a period of preferably 1 to 5 hours, more preferably 2 to 4 hours. The reaction is then carried out at a temperature of preferably 180 to 240°C, more preferably 190 to 220°C, over a period of preferably 5 to 30 hours, more preferably 10 to 20 hours, while removing the solvent from the system. 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 heating pressure to obtain 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 to 10 parts by weight, although this varies depending on the amount of catalyst, the ratio of raw materials used, the temperature, the 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.

[0039] 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.

[0040] 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 (4) above is obtained as the main component by reacting aniline with m-diisopropenylbenzene or m-di(α-hydroxyisopropyl)benzene at 180 to 250°C in the presence of an acidic catalyst. The n=1 compound contains three isomers of compounds with a symmetric structure having the same orientation to two aniline molecules, such as 1,3-bis(p-aminocumyl)benzene and 1,3-bis(o-aminocumyl)benzene, and compounds with an asymmetric structure having 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.

[0041] 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, the desired asymmetric structure compound will be less abundant, 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.

[0042] 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 to 190°C, preferably 160 to 190°C, for 5 to 50 hours, preferably 5 to 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 symmetric structure will take precedence, 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. 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, or by means such as steam distillation.

[0043] 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, and 2-isopropylaniline. Examples include ropylaniline, 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 may be used individually or in combination of two or more.

[0044] 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.

[0045] 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. However, the solvents are not limited to these, and two or more may be used in combination.

[0046] 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.

[0047] 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, phosphoric acid, etc. 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.

[0048] 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.

[0049] 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.

[0050] 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 is the first stage reaction).

[0051] 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 groups of the aromatic amine resin represented by formulas (4) and (5) above.

[0052] To reduce the amount of un-ring-closed 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).

[0053] The re-dehydration and ring-closing reaction takes typically 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 heating pressure, and the solvent may be removed by distillation or another solvent may be added to prepare a resin solution of the desired concentration, or the solvent may be completely removed to obtain a solid resin.

[0054] 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.

[0055] The following describes a method for producing maleimide resin represented by the above formula (3), but it is not limited to this method.

[0056] The maleimide resin represented by the above formula (3) 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.

[0057] 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 even 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, silica, and 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 of 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.

[0058] 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 50,000, more preferably 750 to 40,000, even more preferably 1,000 to 30,000, and particularly preferably 1,500 to 20,000. 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, diffusion becomes difficult during manufacturing, and purification by washing with water becomes difficult.

[0059] The following describes copolymers containing ethylene, styrene, and divinylbenzene. Copolymers can be obtained by copolymerizing at least ethylene, styrene, and divinylbenzene.

[0060] The number-average molecular weight (Mn) of the copolymer in this embodiment can be obtained by GPC, and is preferably 500 or more and less than 30,000, more preferably 750 or more and less than 27,500, and particularly preferably 1,000 or more and less than 25,000.

[0061] The ethylene content in the copolymer of this embodiment is preferably 20% by mass or more and 90% by mass or less, more preferably 25% by mass or more and 90% by mass or less, and particularly preferably 30% by mass or more and 90% by mass or less. When the ethylene content is 20% by mass or more, the toughness (elongation) and impact resistance of the cured product are improved, and cracking during curing and cracking during heat cycle testing of the cured product becomes less likely to occur.

[0062] The styrene content in the copolymer of this embodiment is preferably 0% by mass or more and 90% by mass or less, more preferably 5% by mass or more and 70% by mass or less, and particularly preferably 10% by mass or more and 60% by mass or less. When the styrene content is less than 70% by mass, the glass transition temperature of the cured product is lowered, which is preferable because it improves the toughness and elongation at room temperature. When the styrene content is 10% by mass or more, the aromaticity of the copolymer is improved, the compatibility with flame retardants and fillers is improved, bleed-out of flame retardants can be avoided, and the filler-filling properties can be improved. Furthermore, it is possible to obtain a cured resin composition with high peel strength from copper foil and copper wiring.

[0063] The copolymer of this embodiment may further contain an olefin compound. The olefin compound is one or more selected from α-olefins having 2 to 20 carbon atoms and cyclic olefins having 5 to 20 carbon atoms, and is a compound that is substantially free of oxygen, nitrogen, and halogens, and is composed of carbon and hydrogen. Examples of α-olefins having 2 to 20 carbon atoms include 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, and 3-methyl-1-butene Examples include 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 having 5 to 20 carbon atoms include norbornene and cyclopentene.

[0064] The copolymer of this embodiment may further contain a styrene compound. The styrene compound is an aromatic compound having 8 to 20 carbon atoms and one vinyl group, such as paramethylstyrene, paraisobutylstyrene, vinylnaphthalene, and vinylanthracene. It is not limited to these, and may be used individually or in combination.

[0065] The copolymer of this embodiment may further contain a divinyl compound. A divinyl compound is a compound having 5 to 20 carbon atoms and two vinyl groups, and examples include divinylnaphthalene, divinylanthracene, p-2-propenylstyrene, and p-3-butenylstyrene. Alternatively, for example, 1,2-bis(vinylphenyl)ethane (abbreviated as BVPE) can be used.

[0066] The copolymer of this embodiment may further contain polar groups, such as olefins containing oxygen atoms, nitrogen atoms, etc., aromatic vinyl compounds containing oxygen atoms, nitrogen atoms, etc., or aromatic polyenes containing oxygen atoms, nitrogen atoms, etc. However, the total mass of monomers containing these polar groups is preferably 10% by mass or less, more preferably 3% by mass or less, of the total mass of the resin composition, and most preferably no monomers containing polar groups are included. By keeping it at 10% by mass or less, the dielectric properties of the cured product obtained by curing the curable resin composition of this embodiment can be improved.

[0067] Examples of copolymers in this embodiment include ethylene-styrene-divinylbenzene copolymer, ethylene-propylene-styrene-divinylbenzene copolymer, ethylene-1-hexene-styrene-divinylbenzene copolymer, and ethylene-1-octene-styrene-divinylbenzene copolymer. Specifically, examples include Snecton S-700 (development product number: LDM-03-07), Snecton S-2000 (development product number: LDM-02-C), Snecton N-5000 (development product number: LDM-05-A), Snecton N-7000 (development product number: LDM-07-A), and Snecton S-710 (development product number: LDM-03L) (manufactured by Denka Co., Ltd.).

[0068] The copolymer content in the total amount of the curable resin composition of this embodiment is preferably 1% to 50% by mass, more preferably 3% to 40% by mass, and particularly preferably 5% to 20% by mass. If the content is less than the above range, the dielectric properties of the cured product will not be satisfactory. If the content is more than the above range, the heat resistance will decrease, and defects may occur during solder reflow. Within the above range, good dielectric properties can be obtained without degrading the heat resistance of the cured product.

[0069] When the cured product obtained by curing the curable resin composition of this embodiment is subjected to DMA analysis, it is preferable that the number of inflections in the change of storage modulus at 30°C to 300°C is 1 or less. If the number of inflections is 2 or more, stress will be applied in stages during heating and cooling processes such as substrate fabrication or solder reflow, which may cause delamination of the copper foil or prepreg. If the number of inflections is 1 or less, the application of excess stress can be reduced, and delamination of the copper foil or prepreg can be suppressed. Since the copolymer used in this embodiment has a double bond, it forms a uniform molecular chain by forming a bond with the aromatic maleimide resin, and the number of inflections in the change of elastic modulus can be reduced to 1 or less.

[0070] The Tg of the cured product obtained by curing the curable resin composition of this embodiment, as determined by DMA analysis, is preferably 200°C or higher, more preferably 220°C or higher, and particularly preferably 240°C or higher. The dielectric loss tangent Df is preferably 0.0025 or less, more preferably 0.0023 or less, and particularly preferably 0.0020 or less.

[0071] [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.

[0072] 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 may be used individually or in combination.

[0073] 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.

[0074] The amount of curing accelerator used is 0.01 to 5.0 parts by mass per 100 parts by mass of the curable resin composition, as needed.

[0075] [Inorganic Fillers] The curable resin composition of this embodiment may contain inorganic fillers. 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.

[0076] 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.

[0077] [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 curability and appropriate stability. A radical polymerization initiator is a compound that generates radicals by irradiation with ultraviolet light 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.

[0078] 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 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 are examples, but are not limited to these. Furthermore, these may be used individually or in combination of multiple types. Among the above organic peroxides, ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, and peroxycarbonates are preferred, with dialkyl peroxides being more preferred.

[0079] 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.

[0080] 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.

[0081] [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 into glass cloth and the like, and facilitates B-stage production 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.

[0082] The polymerization inhibitor may be added when synthesizing the aromatic maleimide resin represented by formulas (2) and (3) above, or when synthesizing the copolymer having the constituent units of ethylene, styrene, and divinylbenzene, or it may be added 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 aromatic maleimide resin represented by formulas (2) and (3) above.

[0083] Examples of polymerization inhibitors include phenol-based, sulfur-based, phosphorus-based, hindered amine-based, nitroso-based, and nitroxyl radical-based agents. Furthermore, one polymerization inhibitor may be used, or multiple inhibitors may be used in combination. Of these, phenol-based, hindered amine-based, nitroso-based, and nitroxyl radical-based agents are preferred in this embodiment.

[0084] 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] N,N'-Hexamethylenebis(3,5-di-t-butyl-4-hydroxyhydrocinnamamide), 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 trimethyl-4-hydroxybenzylsulfonate ethyl, 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.

[0085] Examples of sulfur-based polymerization inhibitors include, but are not limited to, dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, and distearyl-3,3'-thiodipropionate.

[0086] Examples of the phosphorus polymerization inhibitors mentioned above include triphenyl phosphite, diphenylisodecyl phosphite, phenyldiisodecyl phosphite, tris(nonylphenyl) phosphite, diisodecylpentaerythritol phosphite, tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis(octadecyl) phosphite, cyclic neopentanetetraylbis(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis(2,4-di-t-butyl-4-methylphenyl) phosphite, and bis[2- Examples include, but are not limited to, phosphites such as t-butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl]hydrogen phosphite, oxaphosphaphenanthrene oxides such as 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.

[0087] Examples of the above hindered amine polymerization inhibitors include 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 Examples include, but are not limited to, LA-52, Chimassorb2020FDL, Chimassorb944FDL, Chimassorb944LD, Tinuvin622SF, TinuvinPA144, Tinuvin765, Tinuvin770DF, TinuvinXT55FB, Tinuvin111FDL, Tinuvin783FDL, Tinuvin791FB, etc.

[0088] Examples of the nitroso polymerization inhibitors mentioned above include, but are not limited to, p-nitrosophenol, N-nitrosodiphenylamine, and ammonium salts of N-nitrosophenylhydroxyamine (cuperone). Of these, ammonium salts of N-nitrosophenylhydroxyamine (cuperone) are preferred.

[0089] 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.

[0090] [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 retardant may be either reactive or additive type. Specific examples include phosphate esters such as trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixylenyl phosphate, 1,3-phenylenebis(dixylenyl phosphate), 1,4-phenylenebis(dixylenyl phosphate), and 4,4'-biphenyl(dixylenyl 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. Of the above example substances, phosphate esters, phosphans, or phosphorus-containing epoxy compounds are preferred, and 1,3-phenylenebis(dixyllinyl phosphate), 1,4-phenylenebis(dixylenyl phosphate), 4,4'-biphenyl(dixylenyl phosphate), or phosphorus-containing epoxy compounds are particularly preferred.

[0091] 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 it 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.

[0092] [Light stabilizer] The curable resin composition of this embodiment may also contain a light stabilizer. A hindered amine-based light stabilizer, particularly HALS, is preferred as the light stabilizer. 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 succinate and 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine, and 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 Examples include, but are not limited to, bis(1,2,2,6,6-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, 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.

[0093] 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.

[0094] [Binder Resin] The curable resin composition of this embodiment may also use a binder resin. Examples of binder resins include butyral resins, acetal resins, acrylic resins, epoxy-nylon resins, NBR-phenolic resins, epoxy-NBR resins, silicone resins, etc., but are not limited to these. Furthermore, these may be used individually or in combination of multiple types.

[0095] 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 is used as needed.

[0096] [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.

[0097] The amount of additive added is preferably 1,000 parts by mass or less, more preferably 700 parts by mass or less, per 100 parts by mass of the curable resin composition.

[0098] The curable resin composition of this embodiment may further contain maleimide resins other than the maleimide resin of this embodiment, epoxy resins, activated ester compounds, phenolic resins, polyphenylene ether compounds, amine resins, compounds having ethylenically unsaturated bonds, isocyanate resins, polyamide resins, cyanate ester resins, polyimide resins, polybutadiene and its modified counterparts, polystyrene and its modified counterparts, polyethylene and its modified counterparts, benzoxazine compounds, etc., and these may be used individually or in combination of multiple types. Among these compounds, it is preferable to include 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, unless otherwise specified, is preferably 80% by mass or less, more preferably 60% by mass or less, and most preferably 40% by mass or less, in the curable resin composition of this embodiment. Furthermore, the preferred lower limit is 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. Within this range, the effects of each added compound can be added 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.

[0099] [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 alone or in combination of multiple types.

[0100] 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, and epoxy resin having a butadiene structure. Specific examples include "RE310S", "RE410S" (both manufactured by Nippon Kayaku Co., Ltd., bisphenol A type epoxy resin), "RE303S", "RE304S", "RE403S", "RE404S" (all manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy resin), "HP4032", "HP4032D", "HP4032SS" (all manufactured by DIC Corporation, naphthalene type epoxy resin), "828US", "jER828EL", "825", "828EL" (all manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin), "jE807", "1750" (both manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin), and "jER152" (manufactured by Mitsubishi Chemical Corporation, phenol Examples include novolac-type epoxy resin, "630", "630LSD" (both manufactured by Mitsubishi Chemical Corporation, glycidylamine-type epoxy resin), "ZX1059" (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., a mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin), "EX-721" (manufactured by Nagase ChemteX Corporation, glycidyl ester-type epoxy resin), "Celoxide 2021P" (manufactured by Daicel Corporation, alicyclic epoxy resin with an ester skeleton), "PB-3600" (manufactured by Daicel Corporation, epoxy resin with a butadiene structure), "ZX1658", "ZX1658GS" (both manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., liquid 1,4-glycidylcyclohexane-type epoxy resin). These may be used individually or in combination of two or more types.

[0101] 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 Corporation, naphthalene-type epoxy resin), "HP-4700", "HP-4710" (both manufactured by DIC Corporation, naphthalene-type tetrafunctional epoxy resins), "N-690" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), "N-695" (manufactured by DIC Corporation, cresol novolac-type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (both manufactured by DIC Corporation, dicyclopentadiene-type epoxy resins), "EXA-7311", and "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-1 "000-2L", "XD-1000-L", "XD-1000-H", "XD-1000-H" (all manufactured by Nippon Kayaku Co., Ltd., dicyclopentadiene type epoxy resin), "ESN475V" (manufactured by Nippon Steel & 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.

[0102] [Active Ester Compounds] Active ester compounds are compounds that contain at least one ester bond in their structure, and on both sides of the ester bond, aliphatic chains, aliphatic rings, or aromatic rings are bonded. 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. They are obtained by a condensation reaction between at least one compound of a carboxylic acid compound, an acid chloride, or a thiocarboxylic acid compound and at least one compound of a hydroxy compound or a thiol compound. In particular, from the viewpoint of improving heat resistance, it is preferable that 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.

[0103] 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.

[0104] Examples of the above-mentioned acid chlorides include 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, trimesic acid chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyldicarbonyl chloride, and 4,4'-azodibenzoyl dichloride.

[0105] 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.

[0106] 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 compound 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.

[0107] Commercially available active ester compounds include, for example, active ester compounds containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", "HPC-8000H-65TM", "EXB-8000L-65TM", and "EXB-8150-65T" (manufactured by DIC Corporation), and active ester compounds containing a naphthalene structure such as "EXB9416-70BK" (manufactured by DIC Corporation), and phenol no Examples of active ester compounds containing acetylated volac include "DC808" (manufactured by Mitsubishi Chemical Corporation), active ester compounds containing benzoylated phenol novolac include "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation), active ester curing agent which is an acetylated phenol novolac includes "DC808" (manufactured by Mitsubishi Chemical Corporation), and phosphorus atom-containing active ester curing agent includes "EXB-9050L-62M" manufactured by DIC Corporation.

[0108] 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%).

[0109] [Phenol Resins] Phenolic resins are compounds having two or more phenolic hydroxyl groups in their molecules. 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, reaction products of bisphenols and aldehydes, etc. Furthermore, these may be used individually or in combination of multiple types. Specific examples of the above raw materials are given below, but are not limited to these. <Phenols> Phenol, alkyl-substituted phenol, aromatic-substituted phenol, hydroquinone, resorcinol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, 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. <Substitutive biphenyls> 4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, 4,4'-bis(hydroxymethyl)-1,1'-biphenyl, etc. <Substitutive phenyls> 1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene, etc.

[0110] [Polyphenylene Ether Compounds] From the viewpoint of heat resistance and electrical properties, polyphenylene ether compounds are preferably polyphenylene ether compounds having ethylenically unsaturated bonds, and more preferably polyphenylene ether compounds having acrylic groups, methacrylic groups, or styrene structures. Commercially available products include SA-9000 (manufactured by SABIC, a polyphenylene ether compound having methacrylic groups), OPE-2St 1200, and OPE-2St 2200 (manufactured by Mitsubishi Gas Chemical Co., Ltd., 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. Also, if the molecular weight is greater than 5000, the melt viscosity becomes high, and sufficient fluidity cannot be obtained, which tends to lead to molding defects. Furthermore, reduced reactivity leads to a longer curing time, an increase in unreacted material not incorporated into the curing system, a decrease in the glass transition temperature of the cured product, and a tendency for the heat resistance of the cured product to decrease. If the number-average molecular weight of the polyphenylene ether compound is between 500 and 5000, it is possible to exhibit 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.

[0111] 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 about 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 have hydroxyl groups derived from phenolic compounds that contribute to curing at both ends of the molecular chain, thus maintaining even higher heat resistance, and because functional groups can be introduced to both ends of the molecular chain even after modification with a compound having ethylenically unsaturated bonds. Furthermore, polyphenylene ether compounds obtained by polymerization reactions are preferable because they exhibit excellent fluidity.

[0112] 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.

[0113] [Amine Resins] Amine resins are compounds having 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.

[0114] [Isocyanate resin] An isocyanate resin is a compound that has two or more isocyanate groups in its 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.

[0115] [Polyamide Resins] 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 may be used individually or in combination of multiple types. Specific examples of the above raw materials are given below, but the material is not limited to these.<Diamines> Ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-diaminopentane, 2-methyl 1,8-diaminooctane, dimeramine, cyclohexanediamine, bis-(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, xylylenediamine, norbornanediamine, isophoronediamine, bisaminomethyltricyclodecane, phenylenediamine, diethyltoluenediamine, naphthalenediamine, diaminodiphenylmethane, bis(4-amino-3,5-dimethylphenyl)methane, bis(4-amino-3,5-diethylphenyl)methane 4,4'-methylenebis-o-toluidine, 4,4'-methylenebis-o-ethylaniline, 4,4'-methylenebis-2-ethyl-6-methylaniline, 4,4'-methylenebis-2,6-diisopropylaniline, 4,4-ethylenedianiline, diaminodiphenylsulfone, diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-amino [phenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(1,3-phenylenediisopropylidene)bisaniline, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, 9,9-bis(4-aminophenyl)fluorene, 2,7-diaminofluorene, aminobenzylamine, diaminobenzophenone, etc.<Diisocyanates> 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 acids> 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, dodecane dioyl chloride, azera oil chloride, 2,5-franzicarbonyl dichloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, trimesinate chloride, bis(4-chlorocarbonylphenyl) ether, 4,4'-diphenyl dicarbonyl chloride, 4,4'-azodibenzoyl dichloride, etc. <Lactams> ε-caprolactam, ω-undecane lactam, ω-laurolactam, etc.

[0116] [Polyimide Resin] Examples of polyimide resins include, but are not limited to, the reaction products of the above-mentioned diamine and the tetracarboxylic dianhydrides exemplified below. Furthermore, these may be used individually or in combination of multiple types. <Tetracarboxylic Dianhydrides> 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2-dicarboxylic anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4 '-diphenylsulfontetracarboxylic 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]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-Dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 2,3,6,7-anthracenetetracarboxylic acid dianhydride, 1,2,7,8-phenanthrenetetracarboxylic acid dianhydride, ethylenetetracarboxylic acid dianhydride, 1,2,3,4-butanetetracarboxylic acid dianhydride, 1, 2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic 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 (Bonic 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 Water compounds, 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.

[0117] [Maleimide resins other than the maleimide resin of this embodiment] The curable resin composition of this embodiment may contain maleimide resins other than the maleimide resin of this embodiment, specifically aliphatic maleimide resins or aromatic maleimide resins with a maleimide equivalent of less than 250 g / eq. or greater than 1000 g / eq., for example, 4,4'-diphenylmethanebismaleimide, polyphenylmethanemaleimide, m-phenylenebismaleimide, 2,2'-bis[4-(4-maleimidophenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, 4,4'-diphenyletherbismaleimide, 4,4'-diphenylsulfonebismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3- Bis(4-maleimidephenoxy)benzene, Zyloc-type maleimide resin (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 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. Maleimide resins, etc., as described in "Continued Story of Epoxy Resin CAS Numbers - Memorandum on Hardener CAS Numbers, Part 32: Bismaleimide (2)" (2019) are examples, but are not limited to these. Furthermore, these may be used individually or in combination of multiple types.

[0118] [Cyanate Ester Resins] Cyanate ester resins are cyanate ester compounds obtained by reacting phenol resins with cyanide halides. Specific examples include, but are not limited to, dicyanate benzene, tricyanate benzene, dicyanate naphthalene, dicyanate biphenyl, 2,2'-bis(4-cyanatephenyl)propane, bis(4-cyanatephenyl)methane, bis(3,5-dimethyl-4-cyanatephenyl)methane, 2,2'-bis(3,5-dimethyl-4-cyanatephenyl)propane, 2,2'-bis(4-cyanatephenyl)ethane, 2,2'-bis(4-cyanatephenyl)hexafluoropropane, bis(4-cyanatephenyl)sulfone, bis(4-cyanatephenyl)thioether, phenol novolac cyanate, and phenol-dicyclopentadiene cocondensates in which the hydroxyl groups have been converted to cyanate groups. Furthermore, these may be used individually or in combination of multiple types. In addition, the cyanate ester compound whose synthesis method is described in Japanese Patent Application Publication No. 2005-264154 is particularly preferred as a cyanate ester compound because it has excellent low hygroscopicity, flame retardancy, and dielectric properties. The cyanate ester resin may also contain catalysts such as zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octoate, tin octoate, lead acetylacetonate, or dibutyltin maleate in order to trimerize the cyanate group and form a sym-triazine ring as needed.

[0119] The catalyst is preferably used in an amount of 0.0001 to 0.10 parts by mass, more preferably 0.00015 to 0.0015 parts by mass, per 100 parts by mass of the cyanate ester resin and curable resin composition.

[0120] [Polybutadiene and its modified products] Polybutadiene and its modified products are compounds that have 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. Furthermore, 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.). 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 volatility is high, making it difficult to adjust the solid content during prepreg preparation, and above the upper limit of the above range, the compatibility with other curable resins deteriorates. In general, 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 mainly composed of hydrocarbons or compounds consisting only of hydrocarbons, due to their polarity. On the other hand, the maleimide resin and copolymer of this embodiment do not have a framework design that actively incorporates heteroatoms such as oxygen and nitrogen, resulting in materials that exhibit low polarity and low dielectric loss tangent, as well as excellent compatibility with compounds composed solely of hydrocarbons.

[0121] [Polystyrene and its modified products] Polystyrene and its modified products are polystyrene or compounds that have a structure derived from polystyrene within their molecules. 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.), and SEEPS (styrene-ethylene / ethylene-propylene-styrene block copolymer: Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099). All manufactured by Kuraray Co., Ltd.), SEBS (styrene-ethylene-butylene-styrene block copolymer: Septon 8004, Septon 8006, Septon 8007L, all manufactured by Kuraray Co., Ltd.), SEEPS-OH (compound having hydroxyl groups at the ends of styrene-ethylene / ethylene-propylene-styrene block copolymer: Septon HG252, manufactured by Kuraray Co., Ltd.), SIS (styrene-isoprene-styrene block copolymer: Septon 5125, Septon 5127, all manufactured by Kuraray Co., Ltd.), Hydrogenated SIS (hydrogenated styrene-isoprene-styrene block copolymer: Hybrar 7125F, Hybrar 7311F Examples include, but are not limited to, polystyrene-isobutylene-styrene block copolymers (SIBS: SIBSTAR073T, SIBSTAR102T, SIBSTAR103T (all manufactured by Kaneka Corporation), Septon V9827 (manufactured by Kuraray Co., Ltd.)), etc. Furthermore, these may be used individually or in combination. Polystyrene and its modified products are preferable to have those without unsaturated bonds because 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 weight-average molecular weight be around 10,000 to 300,000.

[0122] [Polyethylene and Modified Products thereof] Polyethylene and modified products thereof refer to polyethylene or compounds having a structure derived from polyethylene within their molecules. Examples of polyethylene and modified products thereof include, but are not limited to, ethylene-propylene copolymers, ethylene-styrene copolymers, ethylene-propylene-ethylidene norbornene copolymers (Mitsui Chemicals, Ltd. EBT: K-8370EM, K-9330M, etc.), ethylene-propylene-vinyl norbornene copolymers (Mitsui Chemicals, Ltd. 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 and 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.

[0123] [Compounds containing ethylenically unsaturated bonds] Compounds containing ethylenically unsaturated bonds are compounds that have ethylenically unsaturated bonds in their molecule, which can be polymerized by heat or light, regardless of whether a polymerization initiator is used or not. However, compounds that contain ethylenically unsaturated bonds among the aforementioned maleimide resins, copolymers containing ethylene, styrene and divinylbenzene, polystyrene and its modified products, polybutadiene and its modified products, polyethylene and its modified products, etc., are not included in this classification.

[0124] Functional groups having ethylenically unsaturated bonds include, but are not limited to, the following disclosures, vinyl groups, allyl groups (2-propenyl groups), 1-propenyl groups, methallyl groups (2-methyl-2-propenyl groups), (meth)acrylic groups, acenaphthyl groups, indenyl groups, citraconimide groups, itaconimide groups, nadiimide groups, allylnadiimide groups, and cyclopentadienyl groups. Vinyl groups, styryl groups, (meth)acrylic groups, acenaphthyl groups, and indenyl groups are preferred, and vinyl groups, (meth)acrylic groups, acenaphthyl groups, and indenyl groups are more preferred. (Meth)acrylic groups mean methacrylic groups and / or acrylic groups, and (meth)acrylates mean methacrylates and / or acrylates.

[0125] Examples of compounds having a vinyl group include, but are not limited to, compounds having a styryl group, trivinylcyclohexane, 9-vinylfluorene, and thermosetting cycloolefin copolymers (Gigafreak, manufactured by Mitsui Chemicals, and TU-01A, manufactured by Nippon Zeon Co., Ltd.).

[0126] Compounds having a styryl group include, but are not limited to, styrene, vinyltoluene, 2-vinylbiphenyl, 3-vinylbiphenyl, 4-vinylbiphenyl, 1-vinylnaphthalene, 2-vinylnaphthalene, 2-vinylfluorene, α-methylstyrene, α-ethylstyrene, α-propylstyrene, α-n-butylstyrene, α-isobutylstyrene, α-t-butylstyrene, α-n-pentylstyrene, α-2-methylbutylstyrene, α-3-methylbutylstyrene, α-t-pentylstyrene, α-n-hexyl Glustystyrene, α-2-methylpentylstyrene, α-3-methylpentylstyrene, α-1-methylpentylstyrene, α-2,2-dimethylbutylstyrene, α-2,3-dimethylbutylstyrene, α-2,4-dimethylbutylstyrene, α-3,3-dimethylbutylstyrene, α-3,4-dimethylbutylstyrene, α-4,4-dimethylbutylstyrene, α-2-ethylbutylstyrene, α-1-ethylbutylstyrene, α-cyclohexylstyrene, o-ethylvinylbenzene, m-ethylvinylbenzene, p-ethylvinylbenzene, 2-vinyl 2'-ethylbiphenyl, 2-vinyl-3'-ethylbiphenyl, 2-vinyl-4'-ethylbiphenyl, 3-vinyl-2'-ethylbiphenyl, 3-vinyl-3'-ethylbiphenyl, 3-vinyl-4'-ethylbiphenyl, 4-vinyl-2'-ethylbiphenyl, 4-vinyl-3'-ethylbiphenyl, 4-vinyl-4'-ethylbiphenyl, 1-vinyl-2-ethylnaphthalene, 1-vinyl-3-ethylnaphthalene, 1-vinyl-4-ethylnaphthalene, 1-vinyl-5-ethylnaphthalene, 1-vinyl-6-ethylnaphthalene, 1-vinyl- 7-ethylnaphthalene, 1-vinyl-8-ethylnaphthalene, 2-vinyl-1-ethylnaphthalene, 2-vinyl-3-ethylnaphthalene, 2-vinyl-4-ethylnaphthalene, 2-vinyl-5-ethylnaphthalene, 2-vinyl-6-ethylnaphthalene, 2-vinyl-7-ethylnaphthalene, 2-vinyl-8-ethylnaphthalene, m-methylstyrene, p-methylstyrene, m-propylstyrene, p-propylstyrene, m-n-butylstyrene, p-n-butylstyrene, m-t-butylstyrene, p-t-butylstyrene, m-n-hexylstyrene,p-n-hexylstyrene, m-cyclohexylstyrene, p-cyclohexylstyrene, 2-vinyl-2'-propylbiphenyl, 2-vinyl-3'-propylbiphenyl, 2-vinyl-4'-propylbiphenyl, 3-vinyl-2'-propylbiphenyl, 3-vinyl-3'-propylbiphenyl, 3-vinyl-4'-propylbiphenyl, 4-vinyl-2'-propylbiphenyl, 4-vinyl-3'-propylbiphenyl, 4-vinyl-4'-propylbiphenyl, 1-vinyl-2-propylnaphthalene, 1-vinyl-3-propylnaphthalene, 1- Vinyl-4-propylnaphthalene, 1-vinyl-5-propylnaphthalene, 1-vinyl-6-propylnaphthalene, 1-vinyl-7-propylnaphthalene, 1-vinyl-8-propylnaphthalene, 2-vinyl-1-propylnaphthalene, 2-vinyl-3-propylnaphthalene, 2-vinyl-4-propylnaphthalene, 2-vinyl-5-propylnaphthalene, 2-vinyl-6-propylnaphthalene, 2-vinyl-7-propylnaphthalene, 2-vinyl-8-propylnaphthalene, o-ethoxystyrene, m-ethoxystyrene, p-ethoxystyrene, o- Propoxystyrene, m-propoxystyrene, p-propoxystyrene, o-n-butoxystyrene, m-n-butoxystyrene, p-n-butoxystyrene, o-isobutoxystyrene, m-isobutoxystyrene, p-isobutoxystyrene, o-t-butoxystyrene, m-t-butoxystyrene, p-t-butoxystyrene, o-n-pentoxystyrene, m-n-pentoxystyrene, p-n-pentoxystyrene, α-methyl-o-butoxystyrene, α-methyl-m-butoxystyrene, α-methyl-p-butoxystyrene, o-t-pent Xystyrene, m-t-pentoxystyrene, p-t-pentoxystyrene, o-n-hexoxystyrene, m-n-hexoxystyrene, p-n-hexoxystyrene, α-methyl-o-pentoxystyrene, α-methyl-m-pentoxystyrene, α-methyl-p-pentoxystyrene, o-cyclohexoxystyrene, m-cyclohexoxystyrene, p-cyclohexoxystyrene, o-phenoxystyrene, m-phenoxystyrene, p-phenoxystyrene, divinylbenzene, divinylnaphthalene, divinylbiphenyl, divinylfluorene,BVPM (bis(vinylphenyl)methane), BVPE (bis(vinylphenyl)ethane), BVPH (bis(vinylphenyl)hexane), poly(arylene ether) polymers (HC-G0037, HC-G0024, HC-G0030, HC-G0038, all manufactured by JSR Corporation. These may contain monomer units containing pyridazine, pyrimidine, or pyrazine groups), fluorenes or indenes and halogenated compounds containing ethylenically unsaturated bonds (chromium Examples include reaction products with methylstyrene (such as allyl chloride, metharyl chloride, acrylate chloride, and methacrylate chloride), compounds described in Japanese Patent No. 6951829, copolymers containing divinylbenzene as a constituent unit (not limited to the following examples, but such as ODV-XET(X3), ODV-XET(X4), and ODV-XET(X5), all manufactured by Nippon Steel Chemical & Material Co., Ltd.), and reaction products of the aforementioned phenolic resin and chloromethylstyrene.

[0127] Compounds having an allyl group include, but are not limited to, the aforementioned phenol resin and allyl chloride reaction products, and reaction products of ethylenically unsaturated bond-containing phenols (2-allylphenol, 4-allylphenol, eugenol, etc.) and halogenated compounds (1,4-bis(chloromethyl)benzene, 4,4'-bis(chloromethyl)biphenyl, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuryl chloride, etc.).

[0128] Compounds having a 1-propenyl group include, but are not limited to, the following disclosures, examples of which are reaction products of ethylenically unsaturated bond-containing phenols (2-propenylphenol, 4-propenylphenol, isoeugenol, etc.) and halogenated compounds (1,4-bis(chloromethyl)benzene, 4,4'-bis(chloromethyl)biphenyl, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuryl chloride, etc.).

[0129] Compounds having a methallyl group include, but are not limited to, the reaction products of the aforementioned phenolic resin and methallyl chloride.

[0130] Compounds having a (meth)acrylic group include, but are not limited to, monofunctional (meth)acrylates, polyfunctional (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, epoxy (meth)acrylates, and reactive oligomers in which these bonds are used in combination, as well as acid-modified products thereof.

[0131] Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, lauryl (meth)acrylate, polyethylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate monomethyl ether, phenylethyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, and tetrahydrofurfuryl (meth)acrylate.

[0132] Examples of polyfunctional (meth)acrylates include tridiclodecane dimethanol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, nonanediol di(meth)acrylate, glycol di(meth)acrylate, diethylene di(meth)acrylate, polyethylene glycol di(meth)acrylate, tris(meth)acryloyloxyethyl isocyanurate, polypropylene glycol di(meth)acrylate, bisphenolethylene oxide di(meth)acrylate, hydrogenated bisphenolethylene oxide (meth)acrylate, bisphenol di(meth)acrylate, ε- Examples include neopentyl glycol di(meth)acrylate modified from caprolactone hydroxypivalate, ε-caprolactone modified dipentaerythritol hexa(meth)acrylate, ε-caprolactone modified dipentaerythritol poly(meth)acrylate, dipentaerythritol poly(meth)acrylate, trimethylolpropane tri(meth)acrylate, triethylolpropane tri(meth)acrylate and its ethylene oxide adducts, pentaerythritol tri(meth)acrylate and its ethylene oxide adducts, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate and its ethylene oxide adducts.

[0133] Also included are mono, di, tri, or tetra(meth)acrylates of triols obtained by adding 1 mole or more of a cyclic lactone compound such as ε-caprolactone, γ-butyrolactone, or δ-valerolactone to 1 mole of pentaerythritol, dimethylolpropane, trimethylolpropane, or tetramethylolpropane; mono or poly(meth)acrylates of triols obtained by adding 1 mole or more of a cyclic lactone compound such as ε-caprolactone, γ-butyrolactone, or δ-valerolactone to 1 mole of dipentaerythritol; and mono(meth)acrylates or poly(meth)acrylates of polyhydric alcohols such as tetraol, pentaol, or hexaol.

[0134] Examples of urethane (meth)acrylates include reaction products of hydroxyl group-containing (meth)acrylates with polyisocyanates and other alcohols used as needed.

[0135] Examples of hydroxyl group-containing (meth)acrylates include hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate; glycerin (meth)acrylates such as glycerin mono (meth)acrylate and glycerin di (meth)acrylate; sugar alcohol (meth)acrylates such as pentaerythritol di (meth)acrylate, pentaerythritol tri (meth)acrylate, dipentaerythritol penta (meth)acrylate, and dipentaerythritol hexa (meth)acrylate; and epoxy (meth)acrylates, which will be described later.

[0136] Examples of polyisocyanates include toluene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, xylene diisocyanate, hydrogenated xylene diisocyanate, dicyclohexanemethylene diisocyanate, and polyisocyanates such as their isocyanurates and biuret reaction products.

[0137] Other alcohols include, for example, tricyclodecanedimethanol, hydrogenated polybutadiene polyol, dimergol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-icosanediol, 1-methyl-1,8- Examples include octanediol, 2-methyl-1,8-octanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, cyclohexane-1,4-dimethanol, polyethylene glycol, polypropylene glycol, diols such as bisphenol A poly(n≒2-20)ethoxydiol and bisphenol A poly(n≒2-20)propoxydiol, and polyester polyols which are reaction products of these diols with dibasic acids or their anhydrides (e.g., succinic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, isophthalic acid, terephthalic acid, phthalic acid, or their anhydrides).

[0138] Examples of polyester (meth)acrylates include monofunctional (poly)ester (meth)acrylates such as caprolactone-modified 2-hydroxyethyl (meth)acrylate, ethylene oxide and / or propylene oxide-modified phthalic acid (meth)acrylate, ethylene oxide-modified succinic acid (meth)acrylate, and caprolactone-modified tetrahydrofurfuryl (meth)acrylate; polyfunctional (poly)ester (meth)acrylates such as hydroxypivalate ester neopentyl glycol di(meth)acrylate, caprolactone-modified hydroxypivalate ester neopentyl glycol di(meth)acrylate, and epichlorohydrin-modified phthalic acid di(meth)acrylate; and mono, di, or tri(meth)acrylates of triols obtained by adding 1 mole or more of cyclic lactone compounds such as ε-caprolactone, γ-butyrolactone, and δ-valerolactone to 1 mole of trimethylolpropane or glycerin.

[0139] Furthermore, examples include (meth)acrylates of polyester polyols, which are reaction products of diol components such as (poly)ethylene glycol, (poly)propylene glycol, (poly)tetramethylene glycol, (poly)butylene glycol, 3-methyl-1,5-pentanediol, and hexanediol with polybasic acids such as maleic acid, fumaric acid, succinic acid, adipic acid, phthalic acid, isophthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid, dimer acid, sebacic acid, azelaic acid, and 5-sodium sulfoisophthalic acid, and their anhydrides; and (meth)acrylates of cyclic lactone-modified polyester diols, which consist of diol components, polybasic acids, and their anhydrides with ε-caprolactone, γ-butyrolactone, δ-valerolactone, etc.

[0140] Examples of epoxy (meth)acrylates include reaction products of the aforementioned epoxy resin with compounds that contain both polymerizable ethylenically unsaturated groups and carboxyl groups in a single molecule.

[0141] Examples of compounds that contain both polymerizable ethylenically unsaturated groups and carboxyl groups in a single molecule include (meth)acrylic acids, crotonic acid, α-cyanocinnamic acid, cinnamic acid, or reaction products of saturated or unsaturated dibasic acids with unsaturated group-containing monoglycidyl compounds. Examples of acrylic acids include (meth)acrylic acid, β-styrylacrylic acid, β-furfurylacrylic acid, (meth)acrylic acid dimers, semi-esters which are equimolar reaction products of saturated or unsaturated dibasic acid anhydrides with (meth)acrylate derivatives having one hydroxyl group per molecule, and semi-esters which are equimolar reaction products of saturated or unsaturated dibasic acids with monoglycidyl (meth)acrylate derivatives.

[0142] Furthermore, examples of polycarboxylic acid compounds having multiple carboxyl groups in a single molecule include semi-esters which are equimolar reaction products with (meth)acrylate derivatives having multiple hydroxyl groups in a single molecule, and semi-esters which are equimolar reaction products with saturated or unsaturated dibasic acids and glycidyl (meth)acrylate derivatives having multiple epoxy groups.

[0143] Acid-modified (meth)acrylates are those obtained by reacting all or part of the alcoholic hydroxyl groups of a (meth)acrylate, which has alcoholic hydroxyl groups, with a carboxylic acid or its anhydride to introduce carboxyl groups. Examples of carboxylic acids or their anhydrides include succinic acid, maleic acid, isophthalic acid, terephthalic acid, tetrahydroisophthalic acid, hexahydroisophthalic acid, itaconic acid, 3-methyltetrahydroisophthalic acid, 4-methylhexahydroisophthalic acid, hydrogenated trimellitic acid, trimellitic acid, allylsuccinic acid, citraconic acid, methylsuccinic acid, 2,2-dimethylsuccinic acid, pentadecenylsuccinic acid, dodecenylsuccinic acid, decylsuccinic acid, dodecylsuccinic acid, hexadecylsuccinic acid, octadecylsuccinic acid, bicyclo[2.2.2]octo-2-ene-2,3-dicarboxylic acid, succinic anhydride, maleic anhydride, and phthalic acid anhydride. Examples include aqueous solutions, tetrahydroisophthalic anhydride, hexahydroisophthalic anhydride, itaconic anhydride, 3-methyl-tetrahydroisophthalic anhydride, 4-methyl-hexahydroisophthalic anhydride, hydrogenated trimellitic anhydride, trimellitic anhydride, allylsuccinic anhydride, citraconic anhydride, methylsuccinic anhydride, 2,2-dimethylsuccinic anhydride, pentadecenylsuccinic anhydride, dodecenylsuccinic anhydride, decylsuccinic anhydride, dodecylsuccinic anhydride, hexadecylsuccinic anhydride, octadecylsuccinic anhydride, and bicyclo[2.2.2]octo-2-ene-2,3-dicarboxylic acid anhydride.

[0144] Compounds having an acenaphthyl group are not limited to the following disclosures, but include, for example, acenaphthylene, 1-methylacenaphthylene, 3-methylacenaphthylene, 4-methylacenaphthylene, 5-methylacenaphthylene, 1-ethylacenaphthylene, 3-ethylacenaphthylene, 4-ethylacenaphthylene, 5-ethylacenaphthylene, 5-propylacenaphthylene, 3,8-dimethylacenaphthylene, 5,6-dimethylacenaphthylene, 1-chloroacenaphthylene, 3-chloroacenaphthylene, 4-chloroacenaphthylene, 5-chloroacenaphthylene Examples include phthalene, 1-bromoacenaphthalene, 3-bromoacenaphthalene, 4-bromoacenaphthalene, 5-bromoacenaphthalene, 1-phenylacenaphthalene, 3-phenylacenaphthalene, 4-phenylacenaphthalene, 5-phenylacenaphthalene, 3-methoxyacenaphthalene, 3-ethoxyacenaphthalene, 3-butoxyacenaphthalene, 4-methoxyacenaphthalene, 4-ethoxyacenaphthalene, 4-butoxyacenaphthalene, 5-methoxyacenaphthalene, 5-ethoxyacenaphthalene, and 5-butoxyacenaphthalene.

[0145] Compounds having an indenyl group include, but are not limited to, indene, methyl indene, ethyl indene, propyl indene, butyl indene, t-butyl indene, sec-butyl indene, n-pentyl indene, 2-methyl-butyl indene, 3-methyl-butyl indene, n-hexyl indene, 2-methyl-pentyl indene, 3-methyl-pentyl indene, 4-methyl-pentyl indene, methoxy indene, ethoxy indene, butoxy indene, t-butoxy indene, sec-butoxy indene, n-pentoxy indene, 2-methyl-butoxy indene, 3-methyl-butoxy indene, n-hexoxy indene, 2-methyl-pentoxy indene, 3-methyl-pentoxy indene, and 4-methyl-pentoxy indene.

[0146] Compounds having a citracomide group include, but are not limited to, o-phenylenebiscitraconimide, m-phenylenebiscitraconimide, p-phenylenebiscitraconimide, 4,4-diphenylmethanebiscitraconimide, 2,2-bis[4-(4-citraconimidophenoxy)phenyl]propane, bis(3,5-dimethyl-4-citraconimidophenyl)methane, bis(3-ethyl-5-methyl-4-citraconimidophenyl)methane, and bis(3,5-diethyl-4-citraconimidophenyl)methane.

[0147] Compounds having an itaconiamide group include, but are not limited to, N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, and N-laurylitaconimide.

[0148] Compounds having a nadiimide group include, but are not limited to, the following disclosures, 5-norbornene-2,3-dicarboxylic acid imide (so-called nadiimide), N-methylnadiimide, N-phenylnadiimide, o-phenylenebisnadiimide, m-phenylenebisnadiimide, p-phenylenebisnadiimide, 4,4'-diphenylmethanebisnadiimide, 2,2-bis[4-(4-nadiimoidphenoxy)phenyl]propane, bis(3,5-dimethyl-4-nadiimoidphenyl)methane, bis(3-ethyl-5-methyl-4-nadiimoidphenyl)methane, and bis(3,5-diethyl-4-nadiimoidphenyl)methane.

[0149] Compounds having an arylnadiimide group include, but are not limited to, the following disclosures, N-arylnadiimide (N-allyl-5-norbornene-2,3-dicarboxylic acid imide), N-allyl-N-methylnadiimide, N-allyl-N-phenylnadiimide, o-phenylenebis(N-arylnadiimide), m-phenylenebis(N-arylnadiimide), p-phenylenebis(N-arylnadiimide), 4,4'-diphenylmethanebis(N-arylnadiimide), 2,2-bis[4-(4-N-arylnadiimoidphenoxy)phenyl]propane, bis(3,5-dimethyl-4-N-arylnadiimoidphenyl)methane, and bis(3-ethyl-5-methyl-4-N-arylnadiimoidphenyl)methane.

[0150] Compounds having a cyclopentadienyl group include, but are not limited to, 1,3-cyclopentadiene, 1-methyl-1,3-cyclopentadiene, 2-methyl-1,3-cyclopentadiene, 1,2,3,4-tetramethyl-1,3-cyclopentadiene, and 1,2,3,4,5-pentamethyl-1,3-cyclopentadiene.

[0151] [Benzoxazine Compounds] As benzoxazine compounds, any compound having two or more dihydrobenzoxazine rings in one molecule can be used, as long as it is generally known. Examples include 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., but are not particularly limited. These benzoxazine compounds can be used individually or in appropriate mixtures of two or more.

[0152] The curable resin composition of this embodiment is obtained by preparing the above components in predetermined proportions, pre-curing at 130 to 180°C for 30 to 500 seconds, and then post-curing at 150 to 200°C for 2 to 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.

[0153] The method for preparing the curable resin composition of this embodiment is not particularly limited, but each component may be uniformly mixed or prepolymerized. For example, a mixture of the maleimide resin and copolymer of this embodiment can 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 each component can 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.

[0154] 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 powdery 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 their fluidity and curability with almost no decrease even after storage at -25 to 0°C for more than a week. The resulting molded bodies can be molded into cured products using a transfer molding machine or a compression molding machine.

[0155] The curable resin composition of this embodiment can also be made 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 make 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 can be obtained by heat-drying and then hot-press-molding 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 composition containing carbon fibers can also be obtained directly, for example, by the RTM method.

[0156] 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.

[0157] 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 fibers. The shape of the substrate is not particularly limited, but examples include woven fabrics, nonwoven fabrics, rovings, and chopped strand mats. As for the weaving method of the woven fabric, plain weave, twill weave, etc., are known, and these can be appropriately selected and used depending on the intended application and performance. Furthermore, glass woven fabrics that have been opened or surface-treated with silane coupling agents are preferably used. The thickness of the 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.

[0158] 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 then 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.

[0159] 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), and then dry it to 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 ensure that the resulting resin sheet and circuit board (copper-clad laminate, etc.) exhibit consistent performance in any desired area, and to prevent phenomena such as locally different characteristic values ​​caused by phase separation, uniformity of appearance is required.

[0160] 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.

[0161] 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).

[0162] The organic solvents used here preferably include ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. It is also preferable to use them in a proportion that results in a non-volatile content of 30 to 60% by mass.

[0163] 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 dirt and other debris from adhering to the surface of the resin composition layer and to prevent scratches.

[0164] 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.

[0165] 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.

[0166] 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 x 10 ４ ~107.9 x 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.

[0167] 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).

[0168] 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.

[0169] The curable resin composition of this embodiment exhibits excellent heat resistance and low dielectric properties. Heat resistance can be indicated by the glass transition temperature (Tg) and the change in storage modulus from 30°C to 300°C. Specifically, it is preferable that the heat resistance is 200°C or higher. It is preferable that there is only one inflection point in the elastic modulus from 30°C to 300°C (i.e., only the Tg point). This is because if the elastic modulus changes in multiple stages, stress will accumulate each time, which may cause defects such as peeling of the copper foil or prepreg on the substrate, or cracking of the substrate. Heat resistance can be determined by DMA measurement as shown in the examples described later.

[0170] Low dielectric properties can be determined by the dielectric loss tangent test shown in the examples described later, and it is preferable that the dielectric loss tangent at 10 GHz is 0.0025 or less, and more preferably 0.0020 or less.

[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. • GPC (Gel Permeation Chromatography) analysis columns: SHODEX GPC KF-601 (2), KF-602, KF-602.5, KF-603 Flow rate: 1.5 ml / min. (Synthesis Examples 1 and 2), 0.3 ml / min. (Synthesis Example 3) Column temperature: 40°C Solvent used: THF (Tetrahydrofuran) Detector: RI (Differential Refraction Detector)

[0173] [Synthesis Example 1] Synthesis of Aromatic Amine Resin (A-1) 192 parts aniline, 112 parts toluene, and 100 parts 1,3-bis(2-hydroxy-2-propyl)benzene were charged into a flask equipped with a thermometer, condenser, Dean-Stark azeotropic distillation trap, and stirrer, and 21.5 parts 35% hydrochloric acid was added dropwise over 10 minutes. The system was heated to 160°C, and the reaction was carried out at the same temperature for 17 hours while distilling off water and toluene. After cooling to 80°C, 124 parts toluene was added, and 30 parts 30% sodium hydroxide aqueous solution was added dropwise over 10 minutes. The mixture was then stirred at the same temperature for 2 hours and allowed to stand for 30 minutes. The separated lower aqueous layer was removed, and the reaction solution was washed with water repeatedly until the washing solution was neutral. Then, 158 parts of aromatic amine resin (A-1) represented by formula (2) above were obtained by distilling off excess aniline and toluene from the oil layer under heated reduced pressure using a rotary evaporator. The aromatic amine resin (A-1) had an amine equivalent of 186.1 g / eq. and a softening point of 58.8°C. GPC analysis (RI) revealed that the n=1 compound represented 62.5 area %. The GPC chart is shown in Figure 1.

[0174] [Synthesis Example 2] Synthesis of Maleimide Resin (M-1) A flask equipped with a thermometer, condenser, Dean-Stark azeotropic distillation trap, and stirrer was charged with 73.5 parts maleic anhydride, 126 parts toluene, 1.86 parts methanesulfonic acid, and 12.6 parts N-methyl-2-pyrrolidone, and heated under reflux. Next, a resin solution prepared by dissolving 93 parts aromatic amine resin (A-1) in 55.8 parts toluene was added dropwise over 4 hours while maintaining reflux. During this time, the condensed water and toluene that formed azeotropically under reflux conditions were cooled and separated in the Dean-Stark azeotropic distillation trap. The toluene, which is the organic layer, was returned to the system, and the water was discharged from the system. After the addition of the resin solution dropwise was completed, the reaction was carried out for 10 hours while maintaining reflux and performing dehydration. After the reaction was completed, the mixture was washed with water four times to remove methanesulfonic acid and excess maleic anhydride, and the water was removed from the system by azeotropy of toluene and water under reduced pressure at a temperature below 70°C. Next, 0.93 parts of methanesulfonic acid were added, and the reaction was carried out under reflux for 4 hours. After the reaction was complete, the mixture was washed with water four times until the water became neutral. Then, under reduced pressure and heating at 70°C, water was removed from the system by azeotrope with toluene and water. After that, the solvent was removed by distillation under reduced pressure and heating of toluene until the resin concentration was approximately 70-80%, and then toluene was added to adjust the resin concentration to 60%. This yielded a maleimide solution (V-1) containing maleimide resin (M-1). GPC analysis (RI) of the obtained maleimide resin (M-1) showed that the n=1 isomer was 57.4 area%, the n=2 isomer was 21.3 area%, and the n=3 or more isomers were 21.3 area%. The orientation ratio (ortho-ortho isomer / para-para isomer / ortho-para isomer) in the n=1 isomer was 32.0 area% / 25.4 area% / 42.6 area% by HPLC analysis (225 nm). Furthermore, the softening point was 115.5°C, and the viscosity at 150°C was 6.0 Pa·s. The maleimide equivalent was measured by the method described in Japanese Patent Publication No. 2020-187012 and was 311 g / eq. The GPC chart is shown in Figure 2.

[0175] [Synthesis Example 3] Synthesis of Maleimide Resin (M-2) 191.8 parts toluene, 63.9 parts n-methylpyrrolidone, 123.6 parts 4,4-methylenebis(2-ethyl-6-methylaniline), 4.9 parts methanesulfonic acid, and 260.1 parts styrene-maleic anhydride copolymer (acid value: 151, Mn: 2,454, Mw: 4,997) were charged into a flask equipped with a thermometer, condenser, Dean-Stark azeotropic distillation trap, and stirrer, and the mixture was reacted at 120°C for 15 hours. After cooling, 95.9 parts toluene, 32.0 parts n-methylpyrrolidone, and 103.0 parts maleic anhydride were added, and the reaction was continued under reflux for 6 hours. After cooling, the reaction solution was diluted with 4610.6 parts of toluene, and the organic layer was washed with 1,740 parts of 10% saline solution until the waste liquid became neutral. The organic layer was then washed three times with 1,740 parts of 16.0% isopropanol aqueous solution. Maleimide resin (M-2) was obtained by distilling off the solvent under heating and reduced pressure. The GPC chart of the obtained compound is shown in Figure 3. From the acid value and molecular weight of the raw material styrene-maleic anhydride copolymer, m was calculated to be 41.6 and n to be 6.7. The maleimide equivalent was measured by the method described in Japanese Patent Publication No. 2020-187012 and was 830 g / eq.

[0176] • Maleimide resins: 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., with a softening point of 115.5°C and a viscosity of 5.3 Pa·s at 150°C.) BMI-70 (manufactured by K.I. Chemicals Co., Ltd., bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, molecular weight 442, number of functional groups 2, maleimide equivalent 221 g / eq., with a softening point of 165°C.) BMI-1500 (manufactured by Designer Molecules Inc., molecular weight 1504, number of functional groups 2, maleimide equivalent 752 g / eq.)・Copolymer Snekton S-700 (Development product number: LDM-03-07) (Manufactured by Denka Co., Ltd., copolymer containing ethylene-styrene-divinylbenzene, Mn was 7000.) Snekton S-2000 (Development product number: LDM-02-C) (Manufactured by Denka Co., Ltd., copolymer containing ethylene-styrene-divinylbenzene, Mn was 20000.) Snekton N-5000 (Development product number: LDM-05-A) (Manufactured by Denka Co., Ltd., copolymer containing ethylene-styrene-divinylbenzene, Mn was 9500.) Snekton N-7000 (Development product number: LDM-07-A) (Manufactured by Denka Co., Ltd., copolymer containing ethylene-styrene-divinylbenzene, Mn was 12000.) Snekton S-710 (Development product number: LDM-03L) (Manufactured by Denka Co., Ltd., copolymer containing ethylene-styrene-divinylbenzene, Mn was 4000.) • Polyphenylene ether compound OPE-2St 2200 (manufactured by Mitsubishi Gas Chemical Company, Inc., a polyphenylene ether compound with terminal styrene groups) • Elastomer Septon 2104 (manufactured by Kuraray Co., Ltd., a styrene-ethylene-propylene-styrene copolymer) • Curing accelerator DCP (manufactured by Kayaku Nurion Co., Ltd., dicumyl peroxide) 2E4MZ (manufactured by Shikoku Chemicals Co., Ltd., 2-ethyl-4-methylimidazole)

[0177] [Examples 1-17, Comparative Examples 1-6] [Preparation of Cured Products] Each material was measured out in the proportions (parts by mass) shown in Tables 1-4, and a mixed solvent of toluene / acetone = 3 / 1 (mass%) was added to achieve a resin solid content of 50% by mass. The mixture was then mixed to prepare a varnish. 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 220°C for 2 hours. In Examples 11 and 12, curing was performed at 200°C for 2 hours. If a cured product was obtained, it was marked with ○; if not, it was marked with ×. The results are shown in Tables 1-4.

[0178] <Heat Resistance Test> ・DMA Analysis Using a DMAQ800 manufactured by TA Instruments, the temperature at which a tanδ peak was obtained was defined as Tg under the conditions of a heating rate of 2°C / min, a measurement temperature range of 25°C to 350°C, and a measurement frequency of 10 Hz. In addition, the number of inflection points of the storage modulus from 30°C to 300°C was counted. The sample size was 5 mm wide x 40 mm long, and the test was performed with a thickness of 0.25 mm.

[0179] <Dielectric Constant Test and Dielectric Loss Tangent Test> Tests were performed using a 10 GHz 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.

[0180]

[0181]

[0182]

[0183]

[0184] As is clear from Tables 1 to 4, no cured product was obtained in Comparative Example 1, and Comparative Example 2 showed insufficient heat resistance. Comparative Examples 3 to 6, which used elastomers instead of copolymers, had two inflection points in their storage modulus and two Tg values. On the other hand, Examples 1 to 17 showed excellent dielectric properties while maintaining heat resistance, and had only one inflection point in their storage modulus from 30°C to 300°C.

[0185] The curable resin composition of the present invention 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 lightweight, high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, and in 3D printing applications.

Claims

1. A curable resin composition containing a maleimide resin having a maleimide equivalent of 250 to 1000 g / eq. and having one or more structures represented by the following formula (1) in its molecule, and a copolymer containing ethylene, styrene, and divinylbenzene. (In formula (1), Ar is a substituted or unsubstituted aryl group.) 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). (In formulas (2) and (3), X, R which are present in plural １ , and p each independently exist, and X represents a hydrocarbon group having 1 to 25 carbon atoms. R １ 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, and p is an integer of 0 to 4. n is an average value of the number of repetitions, and 1 < n < 10. Formula (3) has structural units of (a) and (b), and (a) and (b) are each bonded by *, and the repeating positions may be random. m and o are average values of the number of repetitions, and 1 ≤ m ≤ 1000, 1 ≤ o ≤ 1000.) 3. The curable resin composition according to claim 2, wherein X is one of the structures represented by the following formulas (1-a) to (1-f). (In equations (1-a) to (1-f), there are multiple R ２ , R ３ q and t exist independently of each other, R ２ 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. ３ represents a hydrogen atom, a C1-C20 alkyl group, or an aromatic group having C1-C20 that may have substituents. q is an integer from 0 to 4, and t is an integer from 0 to 3. r is the average number of repeats, where 1 < r < 10. * represents the bond position.

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

5. 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, polyphenylene ether compound, amine resin, compound having an ethylenically unsaturated bond, isocyanate resin, polyamide resin, maleimide resin other than the maleimide resin, cyanate ester resin, polyimide resin, polybutadiene and modified thereof, polystyrene and modified thereof, polyethylene and modified thereof, and benzoxazine compound.

6. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 5.

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