JP7836816B2 - Resin compositions, varnishes, laminates, printed circuit boards, and molded products - Google Patents

Description

The present invention relates to a resin composition having low dielectric properties (low relative permittivity, low dielectric loss tangent) that can be used in electronic and electrical components such as laminates, printed circuit boards, adhesives, sealants, paints, and molded products.

Traditionally, thermosetting resins such as epoxy resins, polyimide resins, unsaturated polyester resins, and phenolic resins have been used as heat-resistant resins in the field of electronic materials. These thermosetting resins are selected based on their application and properties. Among these, polyimide resins are particularly well-suited for applications requiring high heat resistance due to their excellent heat resistance and moisture-heat resistance (heat resistance after moisture absorption). Modified polyimide resins, which have improved performance through combinations with other resins such as epoxy resins, are also used.

In the semiconductor substrate field, mounting methods that directly mount semiconductor chips onto substrates are becoming widespread. Therefore, materials used in semiconductors require high heat resistance to withstand high-temperature processing during the mounting process. Epoxy resins are commonly used as semiconductor materials, and research has been conducted to address the demand for improved heat resistance, resulting in the proposal of resins with excellent heat resistance. For example, Patent Document 1 describes a resin composition obtained by melting a component containing a polymaleimide compound.

International Publication WO2020/161926

In recent years, with the increasing performance, capacity, and speed of various electronic devices, electrical signals have been traveling at even higher frequencies. While higher frequencies are advantageous for faster and higher-capacity communications, they can lead to increased dielectric loss, causing signal attenuation and potentially reducing reliability. Therefore, further improvements in low dielectric properties are required for resin compositions suitable for high-frequency substrates used in next-generation communications.
Therefore, the present invention aims to provide a resin composition containing a bismaleimide compound that further improves low dielectric properties. It also aims to provide a resin composition containing a bismaleimide compound that has good solubility and curability in low-boiling point solvents and is easy to handle.

The present invention relates to a resin composition obtained by melting a resin mixture containing (A) a bismaleimide compound, characterized in that the (A) bismaleimide compound comprises an aliphatic bismaleimide compound represented by formula (1) and an aromatic bismaleimide compound represented by formula (2).
(In formula (1), ^R1 is an alkylene group having 6 to 12 carbon atoms.)
(In formula (2), ^R2 is a hydrocarbon group having an aromatic ring with 6 to 30 carbon atoms, ^X1 is independently an oxygen atom or a single bond, ^R3 and ^R4 are hydrocarbon groups having 1 to 6 carbon atoms, and a and b are integers between 0 and 3.)

By including aliphatic bismaleimide compounds and aromatic bismaleimide compounds in the resin composition, it is possible to improve the heat resistance of the cured product while maintaining low dielectric properties. Therefore, it is possible to provide a resin composition with excellent low dielectric properties (low relative permittivity, low dielectric loss tangent) while maintaining heat resistance, which is generally a trade-off with low dielectric properties.

This graph shows the GPC measurement results for the resin composition of Example 67, where the synthesis time was 2.5 minutes.

<First Embodiment>
(Resin composition)
The resin composition of this embodiment is a resin composition obtained by melting a resin mixture containing 30 to 65 parts by mass of (A) a bismaleimide compound, 5 to 25 parts by mass of (B) a coumarone resin, and 1 to 30 parts by mass of (C) an amine compound in 100 parts by mass of the resin component of the resin mixture. The following describes each component (A) to (C) and other components that may be contained in the resin composition. In the present invention, the numerical range "A to B" means "A or more and B or less". The material before melting and mixing each component is called a "resin mixture", and the material after melting and mixing and cooling is called a "resin composition".

(A) Bismaleimide Compounds Bismaleimide compounds are compounds having two maleimide groups and contain an aliphatic bismaleimide compound represented by formula (1) shown in the section on means for solving the problem. By using aliphatic bismaleimide compounds, the low dielectric properties of the cured resin composition are improved. In addition, the cured product has a low water absorption rate after being cured by hot pressing and reaching an oven-dry state. For this reason, even after time has passed since manufacturing, the cured product can stably maintain the low dielectric properties it had immediately after manufacturing.

From the viewpoint of producing a cured product with low dielectric properties, the aliphatic bismaleimide compound is preferably such that ^R1 is an alkylene group having 7 to 11 carbon atoms, and more preferably such that ^R1 is an alkylene group having 9 carbon atoms. Furthermore, an aliphatic bismaleimide compound having a melting point of 120°C or lower is preferred. Examples of such aliphatic bismaleimide compounds include 1,6-bismaleimide(2,2,4-trimethyl)hexane, hexamethylenediaminebismaleimide, N,N'-1,2-ethylenebismaleimide, N,N'-1,3-propylenebismaleimide, and N,N'-1,4-tetramethylenebismaleimide. An example of a commercially available aliphatic bismaleimide compound is BMI-TMH (product name, manufactured by Yamato Chemical Industries, Ltd.).

The bismaleimide compound further contains an aromatic bismaleimide compound represented by formula (2) shown in the section on means for solving the problem. Aromatic bismaleimide compounds with a melting point of 130°C or higher are even more preferred. By containing both an aliphatic bismaleimide compound and an aromatic bismaleimide compound in the resin composition, it is possible to improve the heat resistance of the cured product while maintaining low dielectric properties. Furthermore, because solvent solubility and curability are improved, the resulting resin composition is easy to handle and readily achieves an appropriate B-stage state during prepreg formation.

Aromatic bismaleimide compounds represented by formula (2) include 4,4'-diphenylmethanebismaleimide, bisphenol A diphenyl ether bismaleimide, and 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide. Commercially available aromatic bismaleimide compounds include BMI-1000, BMI-4000, BMI-5000, and BMI-5100 (all product names, manufactured by Yamato Chemical Industries, Ltd.).

From the viewpoint of the heat resistance of the cured product, it is preferable that the ^R2 in formula (2) of the aromatic bismaleimide compound represented by formula (2) is the group represented by formula (3). An example of such an aromatic bismaleimide compound is bisphenol A diphenyl ether bismaleimide.

From the viewpoint of improving the low dielectric properties and heat resistance of the cured product, as well as improving solubility in low-boiling point solvents, the mass ratio of the aliphatic bismaleimide compound to the aromatic bismaleimide compound is preferably 3.0:7.0 to 7.0:3.0, more preferably 4.0:6.0 to 6.0:4.0, and even more preferably 4.5:5.5 to 5.5:4.5, as the ratio of aliphatic bismaleimide compound to aromatic bismaleimide compound.

The content of the bismaleimide compound in 100 parts by mass of the resin component of the resin mixture is 30 to 65 parts by mass. From the viewpoint of achieving both high heat resistance and low dielectric properties of the cured product, the content of the bismaleimide compound in 100 parts by mass is more preferably 40 to 62 parts by mass, and even more preferably 50 to 60 parts by mass. Two or more types of bismaleimide compounds are used in combination. Components (B) to (I) described later and other components can be used individually or in combination of two or more.

(B) Coumarone resin Coumarone resin is a copolymer resin mainly composed of coumarone, indene, and styrene. Commercially available products include G-90, V-120, L-5, L-20, and H-100 (all product names, manufactured by Nippon Paint Chemical Co., Ltd.). From the viewpoint of low dielectric properties of the cured product, coumarone resin having a softening point of 100°C or lower is preferred. Also from the same viewpoint, a weight-average molecular weight of 850 or less is preferred, and a weight-average molecular weight of 800 or less is more preferred. Coumarone resin that is bead-like (solid) at room temperature is preferred over a liquid at room temperature.

From the viewpoint of high heat resistance and low dielectric properties of the cured product, the content of coumarone resin in 100 parts by mass of the resin component of the resin mixture is preferably 5 to 25 parts by mass, more preferably 10 to 20 parts by mass, and even more preferably 13 to 18 parts by mass.

From the viewpoint of solubility in low-boiling point solvents and stability of the dissolved state, the coumarone resin content is more preferably 15 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the bismaleimide compound (A). From the viewpoint of obtaining a cured product with good heat resistance, the coumarone resin content is more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less, per 100 parts by mass of the bismaleimide compound.

(C) Amine compound Aliphatic bismaleimide compounds represented by formula (1) have the problem that once dissolved, they do not solidify and remain liquid. To solve this problem regarding handling, the resin composition of this embodiment contains 1 to 30 parts by mass of an amine compound in addition to the aliphatic bismaleimide compound per 100 parts by mass of the resin component. The content of the amine compound is preferably 2 to 15 parts by mass, and more preferably 3 to 8 parts by mass, from the viewpoint of the curability of the resin composition and the low dielectric properties and heat resistance of the cured product.

Examples of amine compounds include aromatic amines such as bisaniline and 1,3-bis(3-aminophenoxy)benzene. From the viewpoint of obtaining a resin composition with good handling properties as a prepreg, bisaniline is preferred. Examples of commercially available products include bisaniline M and bisaniline-P (manufactured by Mitsui Chemicals Fine, Inc.); ODA, BODA, BAPP, HFBAAPP, BAPB, TPE-M and TPE-Q (all manufactured by Seika Co., Ltd.); Kayabond C-200S (manufactured by Nippon Kayaku Co., Ltd.), BAN (manufactured by Nippon Kayaku Co., Ltd.), and others.

Bisaniline is more preferably an aromatic amine represented by formula (4).
(In formula (4), R ⁵ is a hydrocarbon group having an aromatic ring and between 6 and 30 carbon atoms, and X ¹ is independently either an oxygen atom or a single bond.)

Examples of bisanilines represented by formula (4) include 4,4'-[dimethylmethylenebis(4,1-phenyleneoxy)]bisaniline, 4,4'-[biphenyl-4,4'-diylbis(oxy)]bisaniline, bisaniline-M, and bisaniline-P. Commercially available bisanilines represented by formula (4) include bisaniline-M and bisaniline-P (manufactured by Mitsui Chemicals Fine, Inc.); BODA, BAPP, and BAPB (manufactured by Seika Co., Ltd.).

(D) Benzooxazine compound The benzooxazine compound may have at least one benzooxazine ring in its molecule, but a dihydrobenzooxazine compound represented by the following general formula (5) or (6) is preferred, and a p-d type dihydrobenzooxazine represented by the following general formula (6) is more preferred.
(In formulas (5) and (6), ^R6 and ^R7 represent a hydrogen atom and a substituted or unsubstituted hydrocarbon group having 1 to 3 carbon atoms.)

The content of the benzoxazine compound in 100 parts by mass of the resin component of the resin mixture is preferably 5 to 20 parts by mass, more preferably 10 to 20 parts by mass, and even more preferably 15 to 20 parts by mass, from the viewpoint of high heat resistance and low dielectric properties of the cured product, as well as the solubility of the resin composition in low boiling point solvents.

From the viewpoint of solubility in low-boiling point solvents and stability in the dissolved state in low-boiling point solvents, the content of the benzoxazine compound is more preferably 15 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the bismaleimide compound. From the viewpoint of obtaining a cured product with good heat resistance, the content of the benzoxazine compound is more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less, per 100 parts by mass of the bismaleimide compound.

(E) Bisphenol A type cyanate ester Bisphenol A type cyanate ester is a bisphenol A type cyanate ester (triazine) that hardens by forming a triazine ring. The curability of the resin mixture is improved by the inclusion of bisphenol A type cyanate ester. Bisphenol A type cyanate ester exists as a monomer and a (homo)polymer (polymer), but from the viewpoint of obtaining a cured product with excellent low dielectric properties, the monomer of bisphenol A type cyanate ester is preferred.

From the viewpoint of achieving low dielectric properties of the cured product and preventing precipitation of components at the prepreg stage, the content of bisphenol A type cyanate ester in 100 parts by mass of the resin component of the resin mixture is preferably 0.1 to 3 parts by mass, more preferably 0.5 to 2 parts by mass, and even more preferably 0.7 to 1.3 parts by mass.

(F) Epoxy resin The resin composition may contain epoxy resin as needed, for example, to complement various properties such as flame retardancy. The inclusion of epoxy resin may improve the interlayer adhesion and insulation properties of the laminate obtained by stacking prepregs, which are sheets impregnated with the resin composition into a substrate, and subjecting them to pressurized heat treatment.

Any epoxy resin containing epoxy groups is acceptable, but from the viewpoint of achieving both heat resistance and low dielectric properties of the cured product, biphenyl aralkyl epoxy resins, epoxy resins containing naphthalene rings, and compounds having three epoxy groups are preferred. Among epoxy resins containing naphthalene rings, α-naphthol type epoxy resins are preferred. A commercially available epoxy resin containing naphthalene rings is ESN-475V (product name, manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., α-naphthol type epoxy resin), in which each naphthalene ring has two epoxy groups. Another commercially available high heat-resistant trifunctional epoxy resin is VG3101L (product name, manufactured by Printec Co., Ltd.).

Other epoxy resins besides those mentioned above include bisphenol A type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, triphenylole type epoxy resin, and dicyclopentadiene type epoxy resin.

However, the heat resistance of the cured product can be improved by reducing the content of bisphenol A type epoxy resin in the resin component of the resin mixture. Therefore, from the viewpoint of improving the heat resistance of the cured product, it is preferable that the resin mixture does not contain bisphenol A type epoxy resin. Here, "not containing bisphenol A type epoxy resin" means substantially not containing it, that is, the resin mixture does not contain an amount of bisphenol A type epoxy resin that would affect its properties. For example, if the content of bisphenol A type epoxy resin in 100 parts by mass of the resin component of the resin mixture is 1 part by mass or less, and in some cases 0.3 parts by mass or less or 0.1 parts by mass or less, it will not affect the properties of the resin mixture, such as low dielectric properties.

From the viewpoint of high heat resistance and low dielectric properties of the cured product, the epoxy resin content per 100 parts by mass of the resin component of the resin mixture is preferably 1 to 12 parts by mass, more preferably 2 to 10 parts by mass, and even more preferably 3 to 8 parts by mass.

<Second Embodiment>
(Resin composition)
The resin composition of this embodiment is a resin composition obtained by melting a resin mixture containing (A) a bismaleimide compound, wherein (A) the bismaleimide compound includes an aliphatic bismaleimide compound represented by formula (1) and an aromatic bismaleimide compound represented by formula (2), as shown in the section on means for solving the problem. The resin composition, by containing an aliphatic bismaleimide compound and an aromatic bismaleimide compound, can improve the heat resistance of the cured product while maintaining the low dielectric properties of the cured product. Regarding the bismaleimide compound, matters common to the first embodiment will be omitted from the explanation, and the differences will be explained below.

From the viewpoint of increasing the heat resistance of the cured product, the mass ratio of the two types of bismaleimide compounds in the resin mixture is preferably 25:55 to 45:35, and more preferably 27:53 to 47:38, as aliphatic bismaleimide compound:aromatic bismaleimide compound.

(H) Triallyl isocyanurate The resin composition contains triallyl isocyanurate in the resin mixture from the viewpoint of increasing solubility in low-boiling point solvents. The content of triallyl isocyanurate in 100 parts by mass of the resin component of the resin mixture is preferably 16 to 26 parts by mass, and more preferably 18 to 24 parts by mass. By including triallyl isocyanurate, a resin composition with high solubility in low-boiling point solvents is obtained, which allows for the preparation of a 60% by mass methyl ethyl ketone solution. Examples of commercially available triallyl isocyanurate include TAIC (trademark, manufactured by Mitsubishi Chemical Corporation).

From the viewpoint of improving handling by maintaining the state in the B stage as a solid rather than a viscous solid, the resin composition preferably further contains an amine compound and a carboxylic acid dianhydride.

(C) Amine compound The same amine compound as in the first embodiment can be used. From the viewpoint of providing a resin composition that becomes solid in stage B and has high solubility in low boiling point solvents, if the resin mixture contains triallyl isocyanurate, the content of the amine compound in 100 parts by mass of the resin component of the resin mixture is preferably 8 to 20 parts by mass, more preferably 10 to 18 parts by mass, and even more preferably 12 to 16 parts by mass.

(I) Carboxylic acid dianhydrides Examples of tetracarboxylic acid dianhydrides include BPADA, 6FDA, SFDA, BzDA: Enehyde (trademark, manufactured by ENEOS), TAHQ (abbreviation is shown in the examples). From the viewpoint of obtaining a resin composition that becomes solid in stage B and has high solubility in low boiling point solvents, when the resin mixture contains triallyl isocyanurate, the content of carboxylic acid dianhydrides in 100 parts by mass of the resin component of the resin mixture is preferably 10 to 35 parts by mass, more preferably 15 to 30 parts by mass, and even more preferably 20 to 27 parts by mass.

(G) Curing accelerator When using the resin composition of the present invention as described in the first and second embodiments, a curing accelerator may be added. The timing for adding the curing accelerator may be when the resin composition is dissolved in a solvent to make a varnish, when the varnish is made into a prepreg, or when the substrate or laminate is manufactured. The following description is common to the resin composition of the first and second embodiments.

Examples of curing accelerators include imidazoles such as dicumyl peroxide, 4,4'-diaminodiphenylmethane, 2-methylimidazole, 2-ethyl-4-methylimidazole, and 2-heptylimidazole; amines such as triethanolamine, triethylenediamine, and N-methylmorpholine; organophosphines such as triphenylphosphine and tritlylphosphine; tetraphenylborone salts such as tetraphenylphosphonium tetraphenylborate and triethylammonium tetraphenylborate; 1,8-diazarbicyclo(5,4,0)undecene-7 and its derivatives; and organometallic salts such as lead naphthenate, lead stearate, zinc naphthenate, tin oleate, manganese naphthenate, cobalt naphthenate, and cobalt octoate. Organic peroxides and azo compounds may also be used in combination as needed.

The curing accelerator is incorporated into the varnish or prepreg in a quantity that yields the desired gelling time. For example, the curing accelerator is used in an amount ranging from 0.01 to 5 parts by mass per 100 parts by mass of the total resin components contained in the resin composition.

The resin composition and the resin mixture before melt mixing may contain components other than those listed in (A) to (I) above. For example, organic or inorganic fillers can be used to obtain a base material for a molded product by curing the resin composition. Examples of fillers include oxides such as silica, diatomaceous earth, alumina, zinc chloride, titanium dioxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, and ferrites; hydroxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, and basic magnesium carbonate; carbonates such as calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, dawsonite, and hydrotalcite; sulfates such as calcium sulfate, barium sulfate, and gypsum fiber; calcium silicate (wollonite, xonotlite), talc Examples of materials include clay, mica, montmorillonite, bentonite, activated clay, sepiolite, imogolite, sericite, glass fibers, glass beads, silica-based balloons and other silicates; nitrides such as aluminum nitride, boron nitride, and silicon nitride; carbon compounds such as carbon black, graphite, carbon fibers, carbon balloons, and charcoal powder; and various other metal powders, potassium titanate, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide, stainless steel fibers, zinc borate, various magnetic powders, slag fibers, and ceramic powders.

The filler is preferably spherical or flake-shaped. Additionally, a silane coupling agent having two or more different reactive groups in its molecule (one that reacts chemically with an inorganic material and another that reacts chemically with an organic material) may be used in combination as needed.

When using organic or inorganic fillers, their content is preferably 5.0 to 250 parts by mass per 100 parts by mass of the resin component of the resin mixture.

Flame retardants may be added to the resin composition as needed. Examples of flame retardants include organic flame retardants such as brominated epoxy resins and phosphorus compounds such as condensed phosphate esters, and inorganic flame retardants such as aluminum hydroxide, magnesium hydroxide, tin compounds, and antimony compounds.

Furthermore, it is desirable that the flame retardant be present in a quantity that achieves sufficient flame retardancy (for example, meeting the V-0 condition in the UL94 standard) without impairing the heat resistance and moisture heat resistance of the cured resin composition. In the case of organic flame retardants, for example, 1 to 20 parts by mass per 100 parts by mass of the total resin components including the organic flame retardant in the resin composition is used, and in the case of inorganic flame retardants, 10 to 300 parts by mass per 100 parts by mass of the total resin components is used.

When using the resin composition, other additives can be added depending on the application. Examples of other additives include various silicone oils, thermoplastic resins, synthetic rubbers such as NBR, and leveling agents. For example, the content of the other additives in the resin composition is 0.0001 to 5 parts by mass per 100 parts by mass of the total of the other additives and the resin components.

(Melting and mixing process)
The resin composition of the present invention is manufactured by a melt-mixing process in which a resin mixture is heated and mixed in a molten state. Conventional mixing means can be used in the melt-mixing process. A kneader, a twin-screw kneader, etc., are preferred as mixing means. The temperature during melt-mixing should be above the melting temperature of the resin mixture and below 400°C, but 130 to 230°C is preferred, 150 to 210°C is more preferred, and 170 to 190°C is even more preferred.

The melt-mixing step is preferably carried out under conditions that result in a resin composition with a weight-average molecular weight of 1000 to 2500, and more preferably under conditions that result in a molecular weight of 1200 to 1800. The time for the melt-mixing step is, for example, about 0.1 to 10 minutes, but it is preferable to set the conditions such as the temperature during the melt-mixing step so that the time is about 0.5 to 4 minutes.

After the melt-mixing step, the resin composition of the present invention is obtained by cooling by natural cooling or forced cooling. The cooling method can be appropriately selected from known methods. For example, natural cooling in an environment of 0 to 40°C or forced cooling using a refrigerant can be employed. Alternatively, a method of cooling after melt-mixing in a constant temperature apparatus at an environment of 30 to 300°C may be employed. After cooling, the obtained resin composition can be used as a solid resin composition in subsequent processes.

During the melt-mixing process, at least a portion of the bismaleimide compound is modified by the reaction of the aliphatic bismaleimide compound, the aromatic bismaleimide compound, and other components in the resin mixture. This makes it possible to produce a resin composition with high heat resistance, low dielectric properties, and good solubility and curability in low-boiling point solvents.

From the viewpoint of improving solubility in low-boiling point solvents, it is preferable that the resin composition produced by the melt-mixing process contains components with a molecular weight of 4500 to 4800. The proportion of components with a molecular weight of 4500 to 4800 in 100% by mass of the resin composition is preferably 10 to 20% by mass, and more preferably 12 to 18% by mass. The proportion of components with a molecular weight of 4500 to 4800 can be determined by gel permeation chromatography (GPC) measurement.

(varnish)
The varnish of the resin composition according to the present invention is obtained by dissolving the resin composition obtained by the above-described manufacturing method in a solvent having a boiling point of 120°C or lower and a relative permittivity of 10 to 30.
Examples of solvents with a boiling point of 120°C or lower and a dielectric constant of 10 to 30 include ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ether solvents such as propylene glycol monomethyl ether; and alcohol solvents such as ethanol, 1-propanol, 2-propanol, and 1-butanol. Considering ease of handling, ketone solvents are preferred among the exemplified solvents. Other solvents may also be included.

The resin composition content in 100 parts by mass of varnish is usually 40 to 80 parts by mass, preferably 50 to 70 parts by mass. The varnish can be obtained by dissolving the resin composition in a solvent at room temperature or under heating. When dissolving under heating, the conditions for dissolution depend on the boiling point of the solvent, but for example, the temperature is about 50 to 200°C for about 0.1 to 24 hours.

The prepreg is manufactured by applying or impregnating a substrate with the above-mentioned varnish, and then drying it to remove the solvent. As the substrate, known substrates conventionally used for prepregs, such as glass nonwoven fabric, glass cloth, carbon fiber cloth, organic fiber cloth, and paper, can be used.

After applying or impregnating the above-mentioned varnish to the above-mentioned substrate, a prepreg is manufactured through a drying process. However, the application method, impregnation method, and drying method are not particularly limited, and conventionally known methods can be used. The drying conditions can be appropriately determined depending on the boiling point of the solvent used, but excessively high temperatures are not desirable. It is desirable to dry the prepreg so that the amount of solvent remaining in 100 parts by mass is 3 parts by mass or less.

When manufacturing the prepreg, fillers other than the resin composition described above may be added to the varnish. Examples of fillers include silica particles, alumina particles, and polyphenylene ether resins. From the viewpoint of imparting high heat resistance, low dielectric constant, and low dielectric loss tangent to the cured product, the amount of filler added when preparing the prepreg is preferably 10 to 100 parts by mass, more preferably 10 to 50 parts by mass, and even more preferably 20 to 40 parts by mass, per 100 parts by mass of the resin component of the resin composition. Examples of commercially available silica particle and alumina particle fillers include the AdmaFine series (product name, manufactured by Admatex Co., Ltd.), and examples of commercially available polyphenylene ether resins include SA90, SA120, and SA9000 (product names, all manufactured by SABIC Japan LLC).

The resin composition of the present invention is suitable for printed circuit boards, and the present invention can also be implemented as a molded article obtained by curing the resin composition. Examples of molded articles include cured products obtained by curing only the resin composition, composite materials and laminates obtained by combining the resin composition with other raw materials.

Composite materials and laminates are obtained by heating and curing a single prepreg sheet under pressure using a hot press or the like, or by laminating multiple prepreg sheets and heating them under pressure to integrate them. The heating and pressing conditions when manufacturing composite materials are not particularly limited, but examples include a heating temperature of 100 to 300°C, preferably 150 to 250°C, more preferably 200 to 250°C, a pressure of 10 to 100 kg/ ^cm² , preferably 20 to 40 kg/cm², and a heating and pressing time of 10 to 300 minutes, preferably 30 to 180 minutes.

A laminate can be formed by laminating and integrating metal foil or metal plates onto one or both sides of the laminate, making it suitable for use in multilayer printed circuit boards and the like. The laminate is manufactured by laminating metal foil or metal plates onto one or both sides of a single prepreg, or by laminating metal foil or metal plates onto one or both sides of the outermost layer of multiple prepregs, and then heat-curing the prepreg by hot pressing to integrate them.

Copper, aluminum, iron, stainless steel, etc., can be used as the metal foil or metal plate. For example, a laminate using copper as the metal foil is called a copper-clad laminate (CCL). The conditions for heat curing are preferably the same as those for manufacturing composite materials. Alternatively, a laminate for multilayer printed circuit boards may be used with an inner core material.
The present invention can also be implemented as an adhesive, a sealant, and a coating containing the above-described resin composition.

The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The test methods and raw materials used in the examples and comparative examples are as follows.

1. Test Method [Solvent Solubility (MEK Solubility)]
Sixty parts by mass of the measurement sample (resin composition) and fourty parts by mass of methyl ethyl ketone (solvent) were mixed under conditions of 50°C or below, and the dissolution state after applying ultrasonic vibration for a predetermined time was visually evaluated using the following criteria.
○: After 100 minutes of ultrasonic vibration, the liquid is a clear brown color with no undissolved particles, separation, or turbidity.
×: After 100 minutes of ultrasonic vibration, there is undissolved material, separation, or turbidity.

[Glass transition temperature (Tg)]
[Thermal expansion coefficient: CTE (ppm/°C)]
The cured resin composition was cut to a predetermined size to serve as a sample for glass transition temperature measurement. The glass transition temperature (temperature, °C) and thermal expansion coefficient (CTE) of the sample were measured using DSC (Differential Scanning Calorimeter) and TMA (Thermomechanical Analysis) under the following conditions.
(DSC)
Measuring instrument: Rigaku Thermo Plus EVO2 DSC8231
Sample weight: 5 mg
Atmosphere: N ₂
Measurement temperature: 30-350℃
Heating rate: 10°C/min.
Measurement mode: Heat flux type (TMA)
Measuring instrument: Rigaku Thermo Plus TMA8310
Sample dimensions: Length (vertical) 19 mm x Width (horizontal) 5 mm x Thickness 0.1 mm
Atmosphere: N ₂
Measurement temperature: 30-350℃
Heating rate: 10°C/min.
Measurement mode: Tensile

[Relative permittivity (Dk), dielectric loss tangent (Df)]
Measurements were taken immediately after manufacturing and 24 hours after manufacturing using the cavity resonator method under 1 GHz or 10 GHz conditions. The results obtained using the cavity resonator method were substantially similar under both 1 GHz and 10 GHz conditions. For the measurement of relative permittivity (Dk) and dielectric loss tangent (Df), copper-clad laminates (CCLs) were manufactured using copper as metal foil on both sides of a single prepreg (2116E-glass, resin impregnation rate 40 ± 10%, thickness 0.1 ± 20%). The conditions for hot pressing to heat-cur and integrate the prepreg were a heating temperature of 230°C, a pressure of 20 kg/ ^cm² , and a heating and pressing time of 120 minutes.

For Examples 1 to 42 and Comparative Examples 1 to 4, the relative permittivity (Dk) and dielectric loss tangent (Df) were measured for the cured products.
Examples 43-67 and Comparative Examples 5-7 involved removing copper foil from CCL and cutting it out using a mold to a size of x:y:z = 80 mm × 20 mm × 0.1 mm. The ends of the cut-out pieces were smoothed by removing burrs using sandpaper or the like, and these pieces were used as the measurement targets. The longitudinal direction of the cut-out piece was defined as x, the transverse direction as y, and the thickness direction as z. The dimensions in the y and z directions were measured at three locations with a 20 mm gap in the x direction, and the average value was calculated. The value, rounded to three decimal places, was used as the dimension of the measurement target in the y and z directions.

[Water absorption rate]
The cured samples of Examples 66, 67, and Comparative Example 6 were made into pieces measuring 60 mm in width (vertical) x 60 mm in length (horizontal) x 1.2 mm in height, with all four sides smoothed. The weight of these samples was measured before and after 48 hours of storage under conditions of 85°C and 85% humidity, and the water absorption rate (%) under high temperature and high humidity conditions was evaluated.

[Stage B (Solidification)]
The resin composition was heated to 150-200°C, stirred for 3-5 minutes, and then allowed to cool completely under room temperature conditions. The state of the resin was then evaluated according to the following criteria.
○: The resin becomes a powder or solid, making it easy to recover.
×: The resin becomes a viscous solid, making it difficult to recover.

2. Raw materials (A) Polymaleimide compound BMI-TMH (product name, manufactured by Yamato Chemical Industries, Ltd., 1,6-bismaleimide-(2,2,4-trimethyl)hexane, melting point 73-110°C)
• BMI-4000 (Product name, manufactured by Yamato Chemical Industries, Ltd., bisphenol A diphenyl ether bismaleimide, melting point 134-163°C)
• BMI-2300 (Product name, manufactured by Yamato Chemical Industries, Ltd., polyphenylmethane polymaleimide, melting point 70-145°C)

(B) Coumaron resin G-90 (product name, manufactured by Nippon Paint Chemical Co., Ltd., solid at room temperature, softening point 90°C, weight-average molecular weight 770)
(C) Amine compound - BAPP (product name, manufactured by Seika Co., Ltd., 2,2-bis[4-(4-aminophenoxy)phenyl]propane)
・Bisaniline M (manufactured by Mitsui Chemicals Fine, Inc.)
- Kayabond C-200S (product name, manufactured by Nippon Kayaku Co., Ltd., 4,4'-methylenebis(2,6-dimethylamine))
- ODA (product name, manufactured by Seika Co., Ltd., 4,4'-diaminodiphenyl ether)
BAPB (product name, manufactured by Seika Co., Ltd., 4,4'-bis(4-aminophenoxy)biphenyl)
APB-N (1,3-bis(3-aminophenoxy)benzene)
• BAN (product name, manufactured by Nippon Kayaku Co., Ltd.)

(D) Benzoxazine compound BZO: (P-d type) benzoxazine (manufactured by Shikoku Chemicals Co., Ltd.)

(E) Bisphenol A type cyanate ester triazine (product name, manufactured by Mitsubishi Gas Chemical Company, Inc., CAS No. 1156-51-0, monomer of bisphenol A type cyanate ester, 2,2-bis(4-cyanatophenyl)propane)
(F) Epoxy resin ESN-475V (product name, manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., α-naphthol aralkyl type epoxy resin)

(H) Triallyl isocyanurate Tyke (product name, manufactured by Mitsubishi Chemical Corporation, CAS No. 1025-15-6)

(I) Tetracarboxylic acid dianhydride・BPADA: 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic acid dianhydride・6FDA: 4,4'-(hexafluoroisopropylidene)diphthaltetracarboxylic acid dianhydride・SFDA: spiro[fluorene-9,9'-xanthene]-2',3',6',7'-tetracarboxylic acid dianhydride・6FBBPADA: 5,5'-(((perfluoropropane-2,2-diyl)bis(4,1-phenylene))bis(oxy))bis(isobenzofuran-1,3-dione)
• BzDA: EneHyde (trademark, manufactured by ENEOS)
TAHQ: Bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)1,4-phenylene (CAS No. 2770-49-2)

(Other ingredients: fillers)
• SC2500-SXJ: (Product name, manufactured by Admatex Co., Ltd., silica particles)

(Examples, Comparative Examples)
A resin composition was manufactured by melt-mixing (melt-kneading) resin mixtures in the proportions (parts by mass) shown in Tables 1 to 8 using a twin-screw mixer (kneader). The melt-mixing process was carried out under conditions that the temperature of the resin composition at the outlet of the twin-screw mixer was 170°C ± 10°C.

A resin varnish was produced by mixing 45 parts by mass of the resin mixture manufactured as described above with 55 parts by mass of a solvent under room temperature conditions. In Examples 1 to 22 and Comparative Examples 1 to 4, tetrahydrofuran was used as the solvent, while in Examples 23 to 67 and Comparative Examples 5 to 7, methyl ethyl ketone was used as the solvent.

In Examples 65 and 67, a filler (SC2500-SXJ) was added and dispersed in a ratio of 100 parts by mass per 100 parts by mass of the resin component in the resin composition of the varnish, and this mixture was impregnated into a glass cloth 2116 in a single layer (1-ply) to produce a prepreg. In the other Examples 43 to 67 and Comparative Examples 5 to 7, the prepreg was produced by impregnating the glass cloth 2116 in a single layer without adding polyphenylene ether to the varnish.

Tables ¹ to 8 show the results of measuring the glass transition temperature (Tg), relative permittivity (Dk), and dielectric loss tangent (Df) of each cured product obtained by curing the prepregs of each example and comparative example under the following conditions: press conditions: 180°C × 30 kg/cm² × 1 hour, and main curing conditions: 230°C × 2 hours. Examples 48 and 49 were not included in the measurements because there was a large amount of resin streaking at the time of manufacturing the prepregs.

As shown in Table 1, when a resin mixture containing two bismaleimide compounds, an aliphatic bismaleimide compound of formula (1) and an aromatic bismaleimide compound of formula (2), was melted as (A), the Tg of the cured product was improved compared to when only one of these compounds was used. It is presumed that the improvement in Tg is due to the increased molecular density resulting from the use of the two types of bismaleimide compounds, which led to a cured product with a strong and high-density molecular structure.

The cured resin compositions using the two types of bismaleimide compounds shown in Table 1 exhibit excellent heat resistance and low dielectric properties. However, while they dissolve in high-boiling point solvents such as NMP (N-methyl-2-pyrrolidone), their solubility in low-boiling point solvents such as methyl ethyl ketone is low.
As shown in Table 2, by containing 16 to 23 parts by mass of (H) triallyl isocyanurate in 100 parts by mass of the resin mixture, it was possible to obtain a resin composition that dissolves in low-boiling point solvents while maintaining the characteristics of the cured product, such as excellent heat resistance and low dielectric properties.

The results shown in Tables 2 and 3 indicate that in order to obtain a resin composition with high solubility in low-boiling point solvents by incorporating (H) triallyl isocyanurate, it is necessary to keep the ratio of the two bismaleimide compounds within a predetermined range. Specifically, by setting the mass ratio of the aliphatic bismaleimide compound content to the aromatic bismaleimide compound content in the resin mixture to 25:55 to 45:35, a resin composition with high solubility in low-boiling point solvents was obtained.

As shown in Tables 2 and 3, by setting the mass ratio of the two bismaleimide compounds in the resin mixture within a predetermined range and incorporating (H) triallyl isocyanurate, a resin composition with high solubility in low-boiling point solvents was obtained. However, this resin composition became a viscous solid in the B stage, resulting in poor handling.
As shown in Tables 4 and 5, it was found that by blending 8 to 20 parts by mass of (C) amine compound and 15 to 30 parts by mass of (I) carboxylic acid dianhydride in 100 parts by mass of the resin component of the resin mixture, a resin composition that becomes solid in stage B and has excellent handling properties is obtained. From the viewpoint of obtaining a resin composition with high solubility in low boiling point solvents, the (C) amine compound is preferably one or more selected from the group consisting of APB-N, BAN, and BAPP, and the (I) carboxylic acid dianhydride is preferably one or more selected from the group consisting of BPDA, 6FDA, and SFDA.

From the results shown in Table 6, the following can be concluded.
A cured product with low dielectric properties could be produced using a prepreg made from a resin composition obtained by melting a resin mixture containing components (A) to (C) in 100 parts by mass of the resin component of the resin mixture.
(C) By using bisaniline represented by formula (4) as the amine compound, a resin composition with good handling properties as a prepreg was obtained.
A resin composition obtained by melting a resin mixture containing (A) BMI-TMH and BMI-4000 as polymaleimide compounds and (C) BAPP as an amine compound exhibited good heat resistance (Tg (DSC)) and low dielectric properties (Df (after 24 hours)).

From the results shown in Tables 7 and 8, the following can be concluded.
By setting the mass ratio of BMI-TMH to BMI-4000 to 3.0:7.0 to 7.0:3.0, a cured product with low CTE was obtained.
By limiting the G-90 content in 100 parts by mass of the resin mixture to 12 parts by mass or less, the heat resistance (Tg) of the cured product could be increased.
A cured product with excellent heat resistance was obtained regardless of the triazine content. The inclusion of triazine in the resin mixture increased its viscosity (hardness), improving its handling properties.
From the viewpoint of obtaining a cured product with excellent low dielectric properties, the content of triazine in 100 parts by mass of the resin mixture is preferably 2.0 parts by mass or less, and more preferably 1.0 part by mass or less.
Regardless of the epoxy content, cured products with excellent heat resistance and low dielectric properties were obtained.
In Example 67, where SC2500-SXJ was dispersed as a filler, the best low dielectric properties were achieved. This is presumed to be because molecular bonding due to aggregation was inhibited and resolved by the filler, resulting in the acquisition of high-density molecular bonding.
By using BMI-TMH and BMI-4000 as bismaleimide, a cured product with a lower water absorption rate was obtained compared to Comparative Example 5, which used BMI-2300. Since the cured product obtained by curing the resin composition of the present invention has a low water absorption rate after curing by hot pressing, it is possible to stably maintain the excellent low dielectric properties immediately after manufacturing.

[Consideration of manufacturing conditions]
The optimal manufacturing conditions for the resin composition of Example 67 were investigated from the viewpoint of solvent solubility.
Figure 1 shows the GPC results for a resin composition synthesized for 2.5 minutes.
Table 9 shows the effect of synthesis time on the properties of the resin composition.
[Synthesis conditions]
Resin temperature 170℃±10℃
[Geltime]
Curing time measured on a 171°C hot plate [peak area]
GPC (gel permeation chromatography) measurements were used to determine whether or not components with molecular weights of 4500 to 4800 were detected, and if detected, the percentage of the peak area of components with molecular weights of 4500 to 4800 out of the total peak area was determined.
[Weight average molecular weight]
The weight-average molecular weight of the resin composition was determined by GPC measurement.
Solvent solubility was evaluated using the following criteria.
Sixty parts by mass of the measurement sample (resin composition) and fourty parts by mass of methyl ethyl ketone (solvent) were mixed under conditions of 50°C or below, and the dissolution state after applying ultrasonic vibration for a predetermined time was visually evaluated using the following criteria.
[MEK solubility (168 hours)]
MEK solutions of resins were prepared using the solvent solubility (MEK solubility) method described above, and the condition of the sample after being left for a predetermined time was visually evaluated using the following criteria.
○: No resin precipitation occurred after 168 hours under room temperature conditions.
×: Resin precipitation was observed after 168 hours of storage under room temperature conditions.

From the results shown in Table 9, the following can be concluded.
By increasing the synthesis time, that is, the time spent melting and mixing the resin mixture, the reaction proceeded faster and the gel time was shortened.
Differences in synthesis time resulted in differences in MEK solubility when left standing for extended periods. By increasing the synthesis time to 2.5 minutes or more, a resin composition with good MEK solubility was obtained.
The difference in synthesis time resulted in differences in the peak area and weight-average molecular weight of components with molecular weights of 4500 to 4800 as measured by GPC. Therefore, these can be considered indicators of the synthesis time required to produce resin compositions with good MEK solubility.
By setting the proportion of components with molecular weights of 4500 to 4800, corresponding to the peaks marked with a 1 in the graph of Figure 1, to 10 to 20% of the total, a resin composition with good MEK solubility was obtained.
By setting the weight-average molecular weight to 1100-2500, a resin composition with good MEK solubility was obtained.

[Solvent solubility]
The resin composition of Example 67 (peak area 12.3%, Mw = 1257), synthesized for 2.5 minutes, was evaluated for solubility in solvents other than MEK. As a result, PGM (propylene glycol monomethyl ether), PGM-Ac (propylene glycol monomethyl ether acetate), DMAc (dimethylacetamide), NMP (N-methylpyrrolidone), γ-butyrolactone, ethyl acetate, acetone, toluene, THF (tetrahydrofuran), cyclohexanone, DMF (dimethylformamide), methoxybenzene (anisole), 2-(2-butoxyethoxy)ethanol (ethylene glycol monoethyl ether), and 2-(2-ethoxyethoxy)ethyl acetate (ethyl carbitol acetate) were found to be a brownish transparent liquid after 100 minutes of ultrasonic vibration, with no undissolved residue, separation, or turbidity, indicating good solubility.

The resin composition of the present invention has good solubility in solvents, low dielectric properties (low relative permittivity, low dielectric loss tangent), and high heat resistance. Therefore, it can be used as a raw material for adhesives, sealants, paints, molded products, laminates, and printed circuit boards that are suitable for various high-performance, high-capacity, and high-speed electronic devices and have excellent heat resistance and low dielectric properties.

Claims (19)

(A) A resin composition obtained by melting a resin mixture containing a bismaleimide compound,
The (A) bismaleimide compound is
An aliphatic bismaleimide compound represented by formula (1),
The compound comprises an aromatic bismaleimide compound represented by formula (2),
The resin mixture further contains (H) triallyl isocyanurate,
The resin component is characterized in that, in 100 parts by mass of the resin component comprising an aliphatic bismaleimide compound represented by formula (1), an aromatic bismaleimide compound represented by formula (2), and the (H) triallyl isocyanurate , the content of the (H) triallyl isocyanurate is 16 to 23 parts by mass.
Resin composition.
(In formula (1), ^R1 is an alkylene group having 6 to 12 carbon atoms.)
(In formula (2), ^R2 is a hydrocarbon group having an aromatic ring with 6 to 30 carbon atoms, ^X1 is independently an oxygen atom or a single bond, ^R3 and ^R4 are hydrocarbon groups having 1 to 6 carbon atoms, and a and b are independently integers between 0 and 3.) In the above formula (1), ^R1 is an alkylene group having 9 carbon atoms,
In the above formula (2), ^R2 is the group represented by formula (3),
The resin composition according to claim 1.
The aliphatic bismaleimide compound is 1,6-bismaleimide(2,2,4-trimethyl)hexane,
The aromatic bismaleimide compound is bisphenol A diphenyl ether bismaleimide.
The resin composition according to claim 1. The mass ratio of the content of the aliphatic bismaleimide compound to the content of the aromatic bismaleimide compound in the resin mixture is such that the ratio of the aliphatic bismaleimide compound to the aromatic bismaleimide compound is 25:55 to 45:35.
The resin composition according to claim 3. The resin mixture further contains (C) an amine compound and (I) a carboxylic acid dianhydride.
In 100 parts by mass of a resin component comprising an aliphatic bismaleimide compound represented by formula (1), an aromatic bismaleimide compound represented by formula (2), the (H) triallyl isocyanurate, the (C) amine compound, and the (I) carboxylic acid dianhydride ,
The content of the (C) amine compound is 10 to 20 parts by mass,
The content of the (I) carboxylic acid dianhydride is 15 to 30 parts by mass.
The resin composition according to claim 1. (A) A resin composition obtained by melting a resin mixture containing a bismaleimide compound,
The (A) bismaleimide compound is
An aliphatic bismaleimide compound represented by formula (1),
The compound comprises an aromatic bismaleimide compound represented by formula (2),
The resin mixture further contains (B) coumarone resin and (C) an amine compound.
In 100 parts by mass of a resin component comprising an aliphatic bismaleimide compound represented by formula (1), an aromatic bismaleimide compound represented by formula (2), the coumarone resin (B), and the amine compound (C) ,
The content of the (A) bismaleimide compound, which consists of an aliphatic bismaleimide compound represented by formula (1) and an aromatic bismaleimide compound represented by formula (2), is 30 to 65 parts by mass.
The content of (B) coumarone resin is 5 to 25 parts by mass,
The content of the (C) amine compound is 1 to 30 parts by mass.
Resin composition.
(In formula (1), ^R1 is an alkylene group having 6 to 12 carbon atoms.)
(In formula (2), ^R2 is a hydrocarbon group having an aromatic ring with 6 to 30 carbon atoms, ^X1 is independently an oxygen atom or a single bond, ^R3 and ^R4 are hydrocarbon groups having 1 to 6 carbon atoms, and a and b are independently integers between 0 and 3.) The mass ratio of the content of the aliphatic bismaleimide compound to the content of the aromatic bismaleimide compound is such that the ratio of the aliphatic bismaleimide compound to the aromatic bismaleimide compound is 3.0:7.0 to 7.0:3.0.
The resin composition according to claim 6. The (C) amine compound is bisaniline.
The resin composition according to claim 6. The (C) amine compound is bisaniline represented by formula (4).
The resin composition according to claim 6.
(In formula (4), R ⁵ is a hydrocarbon group having an aromatic ring and between 6 and 30 carbon atoms, and X ¹ is independently either an oxygen atom or a single bond.) The (C) amine compound is bisaniline M, 4,4'-[dimethylmethylenebis(4,1-phenyleneoxy)]bisaniline or (4,4'-[biphenyl-4,4'-diylbis(oxy)]bisaniline).
The resin composition according to claim 6. The resin mixture further contains (D) benzoxazine,
The content of (D) benzoxazine in 100 parts by mass of the resin mixture is 5 to 20 parts by mass.
The resin composition according to claim 6. The aforementioned resin mixture further contains (E) bisphenol A type cyanate ester,
In 100 parts by mass of the resin mixture, the content of (E) bisphenol A type cyanate ester is 0.5 to 2 parts by mass.
The resin composition according to claim 11. The aforementioned resin mixture further contains (F) epoxy,
The content of (F) epoxy in 100 parts by mass of the resin mixture is 1 to 9 parts by mass.
The resin composition according to claim 12. The weight-average molecular weight is 1000 to 2500.
It contains components with a molecular weight of 4500 to 4800, and the proportion of these components is 10 to 20%.
The resin composition according to claim 6. The resin composition according to claim 1, 5, or 6, for use in printed circuit boards. A varnish obtained by dissolving the resin composition according to claim 1, 5, or 6 in a solvent having a boiling point of 120°C or lower and a dielectric constant of 10 to 30. A laminate manufactured using the resin composition described in claim 1, 5, or 6. A printed circuit board manufactured using the resin composition described in claim 1, 5, or 6. A molded article obtained by curing the resin composition according to claim 1, 5, or 6.