Curable compound, and resin composition containing the compound

Abstract

To provide a curable compound that does not precipitate crystals when dissolved in low-boiling point solvents such as toluene and PGMEA, whose cured product can be molded into a film, has low dielectric constant and dielectric loss tangent, and high heat resistance. [Solution] We have found that the above problem can be solved by using a compound obtained by subjecting a polyfunctional maleimide resin of a specific structure to a Michael addition reaction with an aliphatic secondary amine.

Description

Technical Field

[0001] The present invention relates to a compound that can be easily formed into a film by casting a solution into a substrate, can undergo a thermal or photocuring reaction by being used in combination with a radical initiator, and the cured product thereof is excellent in dielectric properties and adhesiveness and is excellent in solvent solubility before curing.

Background Art

[0002] Aromatic bismaleimide is known as a compound having excellent heat resistance and dielectric properties. However, it generally has poor solvent solubility and dissolves only in high-boiling aprotic polar solvents such as NMP and DMF, so it is difficult to use in the field of electronic materials that use low-boiling solvents such as toluene and methyl ethyl ketone. In addition, since the cured product is generally rigid and has no flexibility, it has been difficult to use for film applications. Patent Document 1 discloses a polyfunctional maleimide obtained by reacting a polyfunctional amine resin obtained by reacting aniline with a bishalogenomethyl aralkyl derivative or an aralkyl alcohol derivative with maleic anhydride. Although the maleimide resin having such a structure is soluble in a mixed solvent of toluene and methyl ethyl ketone to some extent, there is a problem that crystals precipitate when left at room temperature for a while. Patent Document 2 discloses a method for improving solvent solubility by subjecting an aromatic bismaleimide to a Michael addition reaction with an aliphatic diamine to increase its molecular weight. However, the polymer composed of this bismaleimide compound and diamine compound has a secondary amine remaining in its structure, and this secondary amine easily reacts with the maleimide group at the molecular end and is likely to cause a crosslinking reaction, so there is a problem that it is likely to gel during the reaction. Patent Documents 3 and 4 disclose methods for improving stability by reacting acetic anhydride with the secondary amine generated after reacting bismaleimide with diamine to acetylate it. However, the resin obtained by such a method has an extremely high linear expansion coefficient of the cured product and a low glass transition temperature, so it is not suitable for applications such as electronic devices that require reliability.

Prior Art Documents

[0003] [Patent Document 1] Patent No. 6429862 [Patent Document 2] Japanese Patent Publication No. 2006-241300 [Patent Document 3] Patent No. 6948907 [Patent Document 4] Publication US8637611 [Overview of the project] [Problems that the invention aims to solve]

[0004] The present invention has been made in view of the above points, and aims to provide a curable compound that has excellent solubility in low-boiling point solvents such as toluene and PGMEA (propylene glycol monomethyl ether acetate), whose cured product has sufficient flexibility to form a film, and which has low dielectric constant and dielectric loss tangent, and low coefficient of linear expansion. [Means for solving the problem]

[0005] As a result of diligent research, the inventors of this invention discovered that the above problems could be solved by using a compound with a specific structure, and thus completed the present invention. In other words, the present invention is (1) Compound represented by the following formula (1)

[0006] [ka]

[0007] (In the formula, R1 and R2 each independently represent an alkyl group having 1 to 18 carbon atoms. m is the average value of the repeating units, ranging from 0.1 to 100. n' is the average value of the repeating units, ranging from 0 to 100.) (2) A resin composition comprising the polymer compound and radical initiator described in item (1) above, (3) The resin composition according to item (2) above, comprising a radical-reactive monomer having one or more functional groups in one molecule. (4) The resin composition according to item (2) above, comprising a radical-reactive polymer having two or more functional groups in one molecule. (5) A cured product of any one of the resin compositions described in item (2) to (4) above, Regarding. [Effects of the Invention]

[0008] The compound and resin composition containing the same according to the present invention exhibit excellent solubility in PGMEA and toluene, which are commonly used in electronic materials, and can be cured by applying heat or light energy in combination with a radical initiator. The cured product of the resin composition can provide a compound with excellent dielectric properties and heat resistance. [Modes for carrying out the invention]

[0009] As a result of diligent research, the inventors discovered that a compound obtained by reacting an aromatic polyfunctional maleimide compound of a specific structure with an aliphatic secondary amine in a specific ratio solves the above problem, and thus completed the present invention.

[0010] The compound of the present invention is a compound represented by the above formula (1). In formula (1), R1 and R2 each independently represent an alkyl group having 1 to 18 carbon atoms. m is the average value of the number of repeating units and is in the range of 0.1 to 100. n' is the average value of the number of repeating units and is in the range of 0 to 100. The relationship with n, which will be described later, is n = m + n'. m is preferably in the range of 0.1 to 80, more preferably in the range of 0.1 to 60, even more preferably in the range of 0.1 to 20, and particularly preferably in the range of 0.1 to 12. n' is preferably in the range of 0 to 80, more preferably in the range of 0.1 to 60, even more preferably in the range of 0.1 to 20, and particularly preferably in the range of 0.1 to 12.

[0011] The aforementioned compound is obtained by reacting a polyfunctional maleimide with an aliphatic secondary amine.

[0012] As the polyfunctional maleimide, a compound of the following formula (2) is used. The polyfunctional maleimide of the following formula (2) may be a commercially available product, and can be obtained, for example, as MIR-3000 (product name, manufactured by Nippon Kayaku Co., Ltd.).

[0013] [Chemical formula]

[0014] In the formula, n is the average value of the number of repeating units and is in the range of 0.1 to 120. n is preferably in the range of 0.1 to 100, more preferably in the range of 0.2 to 80, still more preferably in the range of 0.3 to 50, and particularly preferably in the range of 0.3 to 15.

[0015] Specific examples of the aliphatic secondary amine include dipropylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecanyl amine, n-methyl-n-octylamine, n-methyl-n-nonylamine, n-methyl-n-decanyl amine, n-methyl-n-hexadecylamine, n-methyl-n-octadecylamine, and the like.

[0016] The compound represented by the formula (1) can be obtained by subjecting the polyfunctional maleimide compound having the specific structure and the aliphatic secondary amine to a Michael addition reaction.

[0017] It is preferable to use a solvent in the reaction. Examples of the usable solvent include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and the like. The amount of the solvent used is preferably 10 to 300% with respect to the solid content, and more preferably 20 to 200%.

[0018] The charging ratio of the polyfunctional maleimide compound and the aliphatic secondary amine is preferably 0.05 to 0.5 mol, particularly preferably 0.1 to 0.4 mol of the aliphatic secondary amine per 1 equivalent of maleimide. A reaction catalyst may not be used. The reaction temperature is usually 50 to 150 °C, preferably 60 to 140 °C, and the reaction time is usually 0.5 to 30 hours, preferably 1 to 20 hours. The end of the reaction may be determined by the disappearance of the N-H vibration peak of the secondary amine observed at 3400 to 3500 cm -1 in FT-IR (Fourier transform infrared spectrometer). The solvent used in the reaction may be distilled off under heating and reduced pressure, or may be used as it is as the solvent for the resin composition varnish.

[0019] The resin composition of the present invention contains the compound of the present invention and a radical initiator. The radical initiator may be a thermal radical initiator or a photo radical initiator. Preferred thermal radical initiators include, for example, benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, t-butyl cumyl peroxide, α,α-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumyl peroxide, di-t-butyl peroxyisophthalate, t-butyl peroxybenzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, peroxides such as di(trimethylsilyl) peroxide and trimethylsilyl triphenylsilyl peroxide.

[0020] Examples of preferred photoradical initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, and other benzoin and its alkyl ethers; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, and 1,1-dichloroacetophenone; anthraquinones such as 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone, and 1-chloroanthraquinone; thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, and 2-chlorothioxanthone; acetophenone dimethyl ketal, ben Examples include ketals such as zyldimethylketal; benzophenones such as benzophenone; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1; acylphosphine oxides and xanthones; and oxime esters such as 1,2-octanedione, 1-[4-(phenylthio)phenyl]-,2-(o-benzoyl oxime), ethanone, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(o-acetyl oxime).

[0021] The amount of radical initiator in the resin composition is usually 0.1 to 10 parts by mass, preferably 0.1 to 8 parts by mass, based on 100 parts by mass of the total resin components, such as the compound of the present invention and the radical-reactive monomer, which is an optional component described later.

[0022] The resin composition may also contain radical-reactive monomers. By using radical-reactive monomers in combination, the reactivity of the resin composition of the present invention and the heat resistance of the cured product can be improved. Preferably, radical-reactive monomers have one or more functional groups, and specific examples include acenaphthylene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, glycerin dimethacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, bisphenol A ethylene oxide adduct methacrylate, trimethylolpropane trimethacrylate, tricyclodecane dimethanol dimethacrylate, glycerin dimethacrylate, trimethylolpropane trimethacrylate, ethoxylated isocyanurate triacrylate, ε-caprolactone modified tris-(2-acryloxyethyl) isocyanurate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol polyacrylate, dipentaerythritol hexaacrylate, triallyl isocyanurate, triallyl cyanurate, divinylbenzene, divinyl isophthalate, N-phenyl-maleimide, N-phenyl-methylmaleimide, N-phenyl-chloromaleic acid Mido, Np-chlorophenyl-maleimide, Np-methoxyphenyl-maleimide, Np-methylphenyl-maleimide, Np-nitrophenyl-maleimide, Np-phenoxyphenyl-maleimide, Np-phenylaminophenyl-maleimide, Np-phenoxycarbonylphenyl-maleimide, 1-maleimide-4-acetoxysuccinimide-benzene, 4-maleimide-4'-acetoxysuccinimide-diphenylmethane, 4-maleimide-4'-acetoxysuccinimide- Examples include diphenyl ether, 4-maleimide-4'-acetamide-diphenyl ether, 2-maleimide-6-acetamide-pyridine, 4-maleimide-4'-acetamide-diphenylmethane, and Np-phenylcarbonylphenyl-maleimide N-ethylmaleimide, N-2,6-xylylmaleimide, N-cyclohexylmaleimide, N-2,3-xylylmaleimide, xylylmaleimide, 2,6-xylenemaleimide, and 4,4'-bismaleimide-diphenylmethane. These radical-reactive monomers may be used individually or in combination of two or more.

[0023] The resin composition of the present invention may also contain a radical-reactive polymer. By using a radical-reactive polymer, the adhesion and heat resistance of the cured product of the resin composition of the present invention can be improved. Preferably, the radical-reactive polymer has two or more functional groups, and specific examples include a copolymer of styrene and butadiene, or a modified polyphenylene ether resin, or an imide-extended bismaleimide, or the following formula (4)

[0024] [ka]

[0025] Examples include polymers represented by (3) (wherein m is the average value of the number of repeating units, each independently ranging from 1 to 20).

[0026] The copolymer of styrene and butadiene may be a random copolymer (commonly known as SBR) or a block copolymer. Alternatively, a copolymer obtained by hydrogenating the double bonds derived from butadiene in a block copolymer to create a saturated hydrocarbon (commonly known as SEBS resin) may also be used. The ratio of styrene to butadiene in the polymer is usually 10:90 to 90:10. The number-average molecular weight is usually 1,000 to 100,000. Specific examples of SBR products include Clay Valley's Ricon100, Ricon181, and Ricon184, while specific examples of SEBS resin products include Asahi Kasei Corporation's ToughTec series and Kraton's G Polymer series.

[0027] Examples of modified polyphenylene ether resins include those having methacryloyl groups, acryloyl groups, or vinyl groups at both ends of the molecule and having a number average molecular weight of 1,000 to 10,000. Specific examples include the compound represented by formula (4) below (product name SA9000, manufactured by SABIC Japan LLC), which has methacryloyl groups at both ends and a number average molecular weight of approximately 1,700, or the compound represented by formula (5) below (product name OPE-2St 1200 or OPE-2St 2200, manufactured by Mitsubishi Gas Chemical Company, Ltd.), which has vinyl groups at both ends and a number average molecular weight of approximately 1,200 or 2,200.

[0028] [ka]

[0029] [ka]

[0030] The imide-extended bismaleimide resin used in the present invention can be obtained by known methods described in Japanese Patent Publication No. 5328006, etc. Specifically, it can be obtained by carrying out a dehydration condensation reaction of an aliphatic diamine and an aromatic or aliphatic tetracarboxylic diacitol anhydride in an excess molar ratio in an organic solvent using an acid catalyst, followed by dehydration condensation of the amino group present at the polymer terminal with maleic anhydride, and then removing the catalyst by washing with water.

[0031] Specific examples of aliphatic diamines include 1,10-diaminodecane, 1,12-diaminododecane, dimeramine, 1,2-diamino-2-methylpropane, 1,2-diaminocyclohexane, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,7-diaminoheptane, 1,8-diaminomentane, 1,8-diaminooctane, 1,9-diaminononane, 3,3'-diamino-N-methyldipropylamine, diaminomaleonitrile, 1,3-diaminopentane, and 9,10-diaminophenanthrene, but dimeramine is particularly preferred.

[0032] Specific examples of aromatic or aliphatic tetracarboxylic dianhydrides include pyromellitic anhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bicyclo(2.2.2)octo-7-ene-2,3,5,6-tetracarboxylic dianhydride, diethylenetriaminepentaacetic acid dianhydride, ethylenediaminetetraacetic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, and 4,4'-bisphenol A Diphthalic anhydride, 5-(2,5-dioxytetrahydro)-3-methyl-3-cyclohexene-1,2-dicarbon anhydride, ethylene glycol bis(trimellitic anhydride), hydroquinone diphthalic anhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,1'-bicyclohexane-3,3',4,4'-teto Examples include 3,4:3',4'-dianhydride of racarboxylic acid, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, bicyclo[2.2.2]octo-7-ene-2,3,5,6-tetracarboxylic acid anhydride, 2,3,4,5-tetrahydrofurantetracarboxylic acid anhydride, and 3,5,6-tricarboxy-2-norbornaneacetic acid anhydride, but pyromellitic anhydride and 1,2,4,5-cyclohexanetetracarboxylic acid anhydride are particularly preferred. A specific product name is BMI-3000 from Designer Molecules Inc.

[0033] Organic solvents may be used in combination with the resin composition. Specific examples of organic solvents include aromatic solvents such as toluene and xylene; ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether monoacetate, and propylene glycol monobutyl ether; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone; lactones such as γ-butyrolactone and γ-valerolactone; amide solvents such as N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide, and N,N-dimethylimidazolidinone; and sulfones such as tetramethylene sulfone. The content of the organic solvent in the resin composition of the present invention is usually 90% by mass or less, preferably 30 to 80% by mass.

[0034] The resin composition may also contain a polymerization inhibitor to improve its storage stability. The polymerization inhibitor that can be used is not particularly limited as long as it is generally known, and examples include quinones such as hydroquinone, methylhydroquinone, p-benzoquinone, chloranil, and trimethylquinone, as well as aromatic diols and di-t-butylhydroxytoluene.

[0035] The aforementioned resin composition can be used by adding fillers and additives in amounts that do not impair its original properties, in order to impart desired performance according to its application. The fillers may be in the form of fibers or powders, and examples include silica, carbon black, alumina, talc, mica, glass beads, glass hollow spheres, etc.

[0036] The resin composition may also be used in combination with flame retardant compounds, additives, etc. These are not particularly limited as long as they are commonly used. For example, flame retardant compounds include bromine compounds such as 4,4-dibromoviphenyl, phosphate esters, melamine phosphate, phosphorus-containing epoxy resins, nitrogen compounds such as melamine and benzoguanamine, oxazine ring-containing compounds, and silicon-based compounds. Additives such as UV absorbers, antioxidants, photopolymerization initiators, fluorescent whitening agents, photosensitizers, dyes, pigments, thickeners, lubricants, defoamers, dispersants, leveling agents, and glossing agents can be used in appropriate combinations as desired.

[0037] The aforementioned resin composition can be used by coating or impregnating various substrates. For example, when a thermal radical initiator is used, it can be used as an interlayer insulating layer for multilayer printed circuit boards by coating it onto a PET film, as a coverlay by coating it onto a polyimide film, or as resin-coated copper foil by coating and drying it onto copper foil. It can also be used as a prepreg for printed wiring boards or CFRP by impregnating it with glass cloth, glass paper, carbon fiber, or various nonwoven fabrics. Furthermore, by using a photoradical initiator, it can be used as various resists.

[0038] The aforementioned interlayer insulating layer, coverlay, resin-coated copper foil, prepreg, etc., can be cured by heating and pressing them using a hot press machine or similar device. [Examples]

[0039] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to these examples.

[0040] Example 1 (Synthesis of the compound of the present invention) In a flask equipped with a thermometer, condenser, and stirrer, 30 parts (0.1 maleimide equivalent) of the aromatic polyfunctional maleimide resin represented by formula (2) (product name: MIR-3000, manufactured by Nippon Kayaku Co., Ltd.), 7.23 parts (0.03 mol) of di-n-octylamine, and 30 parts of PGMEA were added and reacted at 100°C for 6 hours. After confirming the disappearance of the peak derived from the NH vibration of di-n-octylamine by FT-IR, a 50% PGMEA solution of the compound of the present invention represented by formula (6) was obtained by adjusting the amount of PGMEA.

[0041] [ka]

[0042] Since the number-average molecular weight of the polyfunctional maleimide compound used as the raw material was 650, the value of the repeating units is calculated to be 1.4 (n=1.4), and therefore the average number of functional groups in this resin is 2.4. Di-n-octylamine was charged at a molar ratio of 0.3 times the amount of maleimide equivalent, and since all of it reacted, the value of m in equation (6) is calculated to be 0.72 and the value of n' is calculated to be 0.68. No crystals precipitated when the PGMEA solution of the compound obtained above was left at room temperature for one week.

[0043] Example 2 (Synthesis of the compound of the present invention) In a flask equipped with a thermometer, condenser, and stirrer, the same procedure was followed except that 30 parts of PGMEA were replaced with 30 parts of toluene to obtain a 50% toluene solution of the compound of the present invention represented by formula (6) as in Example 1. No crystals precipitated when this toluene solution of the compound was left at room temperature for one week.

[0044] Example 3 (Preparation of Resin Composition) The resin composition of the present invention was obtained by uniformly mixing 10 parts of a PGMEA solution of the polymer compound of the present invention obtained in Example 1 with 0.05 parts of dicumyl peroxide as a radical initiator.

[0045] Example 4 (Evaluation of dielectric properties and heat resistance of cured resin composition) The resin composition obtained in Example 3 was applied to a mirror surface of an 18 μm thick copper foil to a thickness of 140 μm using an applicator, and the solvent was dried by heating at 130°C for 10 minutes. The resulting film-like adhesive on the copper foil was heated and cured in a vacuum oven at 180°C for 1 hour, and then the copper foil was removed by immersion in an etching solution. A cured product with a thickness of 70 μm that could be handled as a film was obtained from the film-like adhesive made from the resin composition of the present invention, and the dielectric properties were evaluated using the cured product obtained above. The dielectric properties were evaluated by measuring the dielectric constant and dielectric loss tangent at 10 GHz using the cavity resonance method with a network analyzer 8719ET (manufactured by Agilent Technologies). The glass transition temperature and linear expansion coefficient (α1) of the test piece were also determined using a TMA (thermomechanical analyzer). The results are shown in Table 1.

[0046] [Table 1]

[0047] Comparative Example 1 When 30 parts of MIR-3000 and 30 parts of PGMEA were stirred at 100°C until completely dissolved, and then returned to room temperature, fine crystals began to precipitate and the solution became cloudy. A comparative resin composition was obtained by adding 0.05 parts of dicumyl peroxide as a radical initiator to 10 parts of this solution and mixing uniformly. Similar to the example, it was coated to a thickness of 140 μm onto the matte surface of a 12 μm thick low-roughness copper foil for high-frequency applications, heated at 130°C for 10 minutes to dry the solvent, and then heated and cured in a vacuum oven at 180°C for 1 hour. After that, the copper foil was removed by immersion in an etching solution. The cured product was brittle and it was impossible to measure its physical properties as a film.

[0048] As described above, the compounds of the present invention are soluble in low-boiling point solvents commonly used in electronic materials, such as PGMEA and toluene. When cured with a radical initiator, the compositions form flexible films and exhibit excellent dielectric properties and heat resistance.

Claims

1. A compound represented by the following formula (1). 【Chemistry 1】 (In the formula, R １ , R ２ Each of these independently represents an alkyl group having 1 to 18 carbon atoms. m is the average value of the repeating units, ranging from 0.1 to 100. n' is the average value of the repeating units, ranging from 0 to 100.

2. A resin composition comprising the compound and radical initiator described in claim 1.

3. The resin composition according to claim 2, comprising a radical-reactive monomer having one or more functional groups in one molecule.

4. The resin composition according to claim 2, comprising a radical-reactive polymer having two or more functional groups in one molecule.

5. A cured product of the resin composition according to any one of claims 2 to 4.

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