Polyimide resin, resin composition containing said polyimide resin, and cured product thereof

Abstract

To provide a resin material which is suitably usable for a printed wiring board and has a new structure, and a resin composition which contains the resin material, is excellent in a coating property to a base material, and provides a cured product that is excellent in adhesion to a metallic foil having low roughness and a base material, mechanical characteristics, heat resistance and dielectric characteristics.SOLUTION: A polyimide resin is a copolymer of an amino compound (A) containing a linear aliphatic diamino compound (a1) which has amino groups at both terminals and 1 to 4 methyl groups and / or ethyl groups at a side chain, and has a 17-24C main chain and an aromatic diamino compound (a2), and a tetrabasic acid dianhydride (B).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to polyimide resins having novel structures, resin compositions containing the same, and cured products of the resin compositions. [Background technology]

[0002] Printed wiring boards are essential components for mobile communication devices such as smartphones and tablets, communication base station equipment, computers, car navigation systems, etc. Printed wiring boards are made of various resin materials that have excellent properties such as adhesion to metal foil, heat resistance, and flexibility. Furthermore, in recent years, development has been underway for high-speed, high-capacity printed wiring boards for next-generation high-frequency wireless applications, and in addition to the above-mentioned characteristics, resin materials are required to have low transmission loss, i.e., low dielectric constant and low dielectric dissipation factor.

[0003] Polyimide resins, which have excellent properties such as heat resistance, flame retardancy, flexibility, electrical properties, and chemical resistance, are widely used in electrical and electronic components, semiconductors, communication devices and their circuit components, peripheral devices, etc. On the other hand, hydrocarbon compounds such as petroleum and natural oils are known to exhibit high insulating properties and low dielectric constants. Patent Documents 1 and 2 describe examples in which long-chain alkyl chains are introduced into polyimide resins, while Patent Document 3 describes examples in which a dimer diamine skeleton, an alkyl with a longer carbon chain, is introduced into polyimide resins. However, although these polyimide resins excel in terms of low dielectric loss tangent, they have high melt viscosities and poor embedding ability in substrate irregularities. As a result, they are prone to the inclusion of air bubbles and reduced adhesion to the substrate, and their heat resistance is insufficient. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-308551 [Patent Document 2] WO2021 / 049503A1 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-119361 Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to provide a resin material having a novel structure that can be suitably used for printed wiring boards, and a resin composition containing the resin material, which has excellent coatability onto substrates, and when cured, has excellent adhesion to metal foils with low roughness and substrates, mechanical properties, heat resistance, and dielectric properties. [Means for solving the problem]

[0006] As a result of extensive research, the present inventors have found that the above problems can be solved by using a polyimide resin having a specific structure, and have thus completed the present invention. That is, the present invention is (1) A polyimide resin which is a copolymer of an amino compound (A) and a tetrabasic acid dianhydride (B), the amino compound (A) including a linear aliphatic diamino compound (a1) having amino groups at both ends and 1 to 4 methyl and / or ethyl groups in the side chain, and an aromatic diamino compound (a2) having 17 to 24 carbon atoms in the main chain, (2) The tetrabasic acid dianhydride (B) is represented by the following formulas (1) to (9):

[0007] [ka]

[0008] (In formula (4), Y represents C(CF3)2, SO2, CO, an oxygen atom, a direct bond, or a group represented by the following formula (10):

[0009] [ka]

[0010] represents a divalent linking group represented by the formula: The polyimide resin according to the above item (1), which contains a compound selected from the group consisting of: (3) The aromatic diamino compound (a2) is (11) to (14)

[0011] [ka]

[0012] In formula (13), R2 independently represents a methyl group or a trifluoromethyl group, and in formula (14), Z represents CH(CH3), SO2, CH2, O-C6H4-O, an oxygen atom, a direct bond, or a group represented by the following formula (10):

[0013] [ka]

[0014] and R3 independently represents a hydrogen atom, a methyl group, an ethyl group, or a trifluoromethyl group. (4) A resin composition containing the polyimide resin according to any one of (1) to (3) above and a thermosetting resin (C). (5) The resin composition according to the above item (4), wherein the thermosetting resin (C) is a maleimide resin. (6) The resin composition according to the above (4) or (5), further containing a curing agent. (7) A cured product of the resin composition according to any one of (4) to (6) above, and (8) An article comprising the cured product according to the preceding item (7). Regarding. [Effects of the Invention]

[0015] The polyimide resin of the present invention has a low melt viscosity, good embedding properties for irregularities in a substrate, and high adhesiveness. Furthermore, by using the polyimide resin of the present invention, it is possible to provide a printed wiring board or the like that is excellent in heat resistance, mechanical properties, low dielectric properties, etc.

[0016] The polyimide resin of the present invention is a copolymer of an amino compound (A) (hereinafter also referred to simply as "component (A)") containing a linear aliphatic diamino compound (a1) (hereinafter also referred to simply as "component (a1)") having 17 to 24 carbon atoms in the main chain, which has amino groups at both terminals and 1 to 4 methyl and / or ethyl groups in its side chains, and an aromatic diamino compound (a2) (hereinafter also referred to simply as "component (a2)"), and a tetrabasic acid dianhydride (B) (hereinafter also referred to simply as "component (B)").

[0017] The component (a1) used in the synthesis of the polyimide resin of the present invention is not particularly limited as long as it is a straight-chain aliphatic hydrocarbon compound having 17 to 24 carbon atoms, has amino groups at both terminals of the main chain, and has 1 to 4 methyl and / or ethyl groups in the side chains. The straight-chain aliphatic hydrocarbon having 17 to 24 carbon atoms that forms the main chain of the component (a1) may be either saturated or unsaturated. Specific examples of the (a1) component include 7-ethylhexadecanediamine, 7,12-dimethyloctadecanediamine, 8,13-dimethyloctadecanediamine, 8-methylnonadecanediamine, 9-methylnonadecanediamine, 7,12-dimethyloctadecanediamine-7,11-ene, and 8,13-dimethyloctadecanediamine-8,12-ene. These may be used alone or in combination of two or more. A commercially available product, Diamine H20 (manufactured by Okamura Oil Mills, Ltd.), is preferably used. The main chain of component (a1) is preferably a saturated aliphatic hydrocarbon, i.e., alkylene, and the number of carbon atoms is preferably 17 to 22, and more preferably 17 to 20. The number of methyl and / or ethyl groups in the side chain is preferably 1 to 3, and more preferably 1 or 2.

[0018] The amount of component (a1) used when synthesizing the polyimide resin of the present invention is preferably an amount within the range of 10 to 50 mass% of the mass (mass of the polyimide resin of the present invention) obtained by subtracting twice the moles of water (water produced by the dehydration condensation reaction) from the mass of component (A). By keeping the amount of component (a1) within this range, the amount of units derived from component (a1) in the polyimide resin falls within the preferred range, thereby preventing an increase in the melt viscosity of the polyimide resin. As a result, the ability of a resin composition containing the polyimide resin (described below) to fill in the irregularities on the substrate surface and the adhesion between the cured resin composition and the substrate are improved, and the incorporation of air bubbles at the interface between the substrate and the resin composition when the resin composition is applied to the substrate is reduced. If the amount of component (a1) is below the above range, the amount of units derived from component (a1) in the polyimide resin will be too small, resulting in a high dielectric loss tangent of the cured product of the resin composition. If the amount of component (a1) is above the above range, the amount of units derived from component (a1) in the polyimide resin will be too large, resulting in a low heat resistance of the cured product of the resin composition.

[0019] The component (a2) used in the synthesis of the polyimide resin of the present invention is not particularly limited as long as it is a compound having two amino groups directly bonded to an aromatic ring in one molecule, and the use of the component (a2) can improve the heat resistance of the polyimide resin. Specific examples of the component (a2) include m-phenylenediamine, p-phenylenediamine, m-tolylenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl thioether, 3,3'-dimethyl-4,4'-diaminodiphenyl thioether, 3,3'-diethoxy-4,4'-diaminodiphenyl thioether, 3,3'- Diaminodiphenyl thioether, 4,4'-diaminobenzophenone, 3,3'-dimethyl-4,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-dimethoxy-4,4'-diaminodiphenyl thioether, 2,2'-bis(3-aminophenyl)propane, 2,2'-bis(4-aminophenyl)propane, 4,4'-diaminodiphenyl Sulfoxide, 3,3'-diaminodiphenylsulfone sulfone, 4,4'-diaminodiphenylsulfone sulfone, benzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 3,3'-diaminobiphenyl, p-xylylenediamine, m-xylylenediamine, o-xylylenediamine, 2,2'-bis(3-aminophenoxyphenyl)propane, 2,2'-bis(4-aminophenoxyphenyl)propane, 1,3-biphenyl Examples of the bis(4-aminophenoxyphenyl)benzene include bis(4-aminophenoxyphenyl)benzene, 1,3'-bis(3-aminophenoxyphenyl)propane, bis(4-amino-3-methylphenyl)methane, bis(4-amino-3,5-dimethylphenyl)methane, bis(4-amino-3-ethylphenyl)methane, bis(4-amino-3,5-diethylphenyl)methane, bis(4-amino-3-propylphenyl)methane, and bis(4-amino-3,5-dipropylphenyl)methane. These may be used alone or in combination of two or more.

[0020] The component (a2) used in the synthesis of the polyimide resin of the present invention preferably contains a compound selected from the group consisting of the following formulae (11) to (14), from the viewpoints of the solubility of the final polyimide resin in a solvent and the heat resistance of a cured product when a resin composition containing the polyimide resin is prepared.

[0021] [ka]

[0022] In formula (13), R2 independently represents a methyl group or a trifluoromethyl group; in formula (14), Z independently represents CH(CH3), SO2, CH2, O-C6H4-O, an oxygen atom, a direct bond, or a divalent linking group represented by formula (10):

[0023] [ka]

[0024] The component (A) used in the synthesis of the polyimide resin of the present invention may be used in combination with a diamino compound (a3) other than the components (a1) and (a2) (hereinafter simply referred to as "component (a3)"). The component (a3) is not particularly limited as long as it is a compound other than the components (a1) and (a2) and has two amino groups in one molecule, but an aliphatic diamino compound other than the component (a1) is preferred, and an aliphatic diamino compound having 6 to 36 carbon atoms other than the component (a1) is preferred because it allows the production of a polyimide resin with a low dielectric constant and dielectric dissipation factor, with dimer diamine being more preferred. Specific examples of the component (a3) include, in addition to the above-mentioned dimer diamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,3-bisaminomethylcyclohexane, norbornanediamine, isophoronediamine, dimer diamine, 2-methyl-1,5-diaminopentane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,4-bis(aminomethyl)cyclohexane, 4,4'-methylenebiscyclohexylamine, and diaminopolysiloxanes having 6 to 36 carbon atoms. These may be used alone or in combination of two or more.

[0025] The dimer diamines described in the section on specific examples of component (a3) are dimers in which two carboxyl groups of a dimer acid, which is a dimer of an unsaturated fatty acid such as oleic acid, have been substituted with primary amino groups (see, for example, Japanese Patent Application Laid-Open No. 9-12712). Specific examples of commercially available dimer diamines include PRIAMINE 1074 and PRIAMINE 1075 (both manufactured by Croda Japan Co., Ltd.) and Versamine 551 (manufactured by Cognis Japan Co., Ltd.). These may be used alone or in combination of two or more. Non-limiting general formulas of dimer diamines are shown below (in each formula, m+n=6 to 17, and p+q=8 to 19, respectively; the dashed lines represent carbon-carbon single or double bonds).

[0026] [ka]

[0027] The tetrabasic acid dianhydride (B) used in the synthesis of the polyimide resin of the present invention is not particularly limited as long as it has two acid anhydride groups in one molecule. Specific examples of component (B) include pyromellitic anhydride, ethylene glycol bis(anhydrotrimellitate), glycerin bis(anhydrotrimellitate) monoacetate, 1,2,3,4-butanetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylethertetracarboxylic dianhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methylcyclohexene-1,2 -dicarboxylic acid anhydride, 3a,4,5,9b-tetrahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, bicyclo(2,2,2)-oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride and bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic acid dianhydride, 5,5'-((propane-2,2-diylbis(4,1-phenylene))bis(oxy))bis(isobenzofuran-1,3-dione), 4,4'-oxydiphthalic anhydride, and the like. Among these, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride or 3,3',4,4'-diphenylethertetracarboxylic dianhydride, and 4,4'-oxydiphthalic anhydride are preferred in terms of solvent solubility and adhesion to substrates. These may be used alone or in combination of two or more.

[0028] The tetrabasic acid dianhydride (B) used in the synthesis of the polyimide resin of the present invention preferably contains a compound selected from the group consisting of the following formulas (1) to (9), from the viewpoint of the solvent solubility of the final polyimide resin.

[0029] [ka]

[0030] In formula (4), Y represents C(CF3)2, SO2, CO, an oxygen atom, a direct bond, or a divalent linking group represented by formula (10) above.

[0031] In the (A) component used in the synthesis of the polyimide resin of the present invention, the number of moles of component (a1) is a1M, the number of moles of component (a2) is a2M, and the number of moles of component (a3) is a3M. The value of (a1M + a3M) / (a1M + a2M + a3M) is preferably greater than 0.2 but less than 0.9, and more preferably greater than 0.3 but less than 0.6. If (a1M + a3M) / (a1M + a2M + a3M) is 0.2 or less, the dielectric properties of the cured resin composition tend to deteriorate, and the solvent solubility of the polyimide resin tends to decrease. Furthermore, if (a1M + a3M) / (a1M + a2M + a3M) is 0.9 or more, the heat resistance of the cured resin composition tends to decrease.

[0032] Furthermore, the value of a2M / (a1M+a2M+a3M) is preferably greater than 0.1 and less than 0.8, and more preferably greater than 0.2 and less than 0.6. When a2M / (a1M+a2M+a3M) is 0.1 or less, the solder heat resistance of the cured product of the resin composition tends to deteriorate. When a2M / (a1M+a2M+a3M) is 0.8 or more, the solvent solubility of the polyimide resin tends to deteriorate.

[0033] When the molar number of component (A) used in the synthesis of the polyimide resin of the present invention is defined as MA and the molar number of component (B) as MB, copolymerization of components (A) and (B) in amounts such that MA / MB > 1 results in a polyimide resin having a polyamic acid resin with amino groups at both ends. In this case, the MA / MB ratio is preferably greater than 1.0 but less than 10.0, and more preferably greater than 1.0 but less than 5.0. If the ratio is greater than 10.0, the resulting polyimide resin will not be sufficiently polymerized. Furthermore, the residual percentage of unreacted raw materials will be high, potentially resulting in reduced heat resistance and other properties of the resin composition (described below) after curing.

[0034] When the molar number of component (A) used in the synthesis of the polyimide resin of the present invention is MA and the molar number of component (B) is MB, copolymerization of component (A) and component (B) satisfying the relationship MB / MA > 1 results in a polyimide resin that is a polyamic acid resin having carboxylic anhydride groups at both ends. In this case, the MB / MA value is preferably greater than 1.0 but less than 10.0, and more preferably greater than 1.0 but less than 5.0. If this value is greater than 10.0, the final polyimide resin will not be sufficiently polymerized. Furthermore, the residual proportion of unreacted raw materials will be high, potentially resulting in reduced properties such as heat resistance after curing of the resin composition (described below).

[0035] The polyimide resin of the present invention can be synthesized by a known method. For example, components (A) and (B) used for synthesis are dissolved in a solvent, and then heated and stirred at 10 to 140°C under an inert atmosphere such as nitrogen, whereby a copolymerization reaction between the diamines and the tetrabasic acid dianhydrides occurs, yielding a polyamic acid resin solution.

[0036] Furthermore, if necessary, a dehydrating agent and / or catalyst may be added to the polyamic acid resin solution obtained above, followed by heating and stirring at 100 to 300°C to induce an imidization reaction (a ring-closing reaction accompanied by dehydration), thereby obtaining the polyimide resin of the present invention. Examples of dehydrating agents that can be used include toluene and xylene, and examples of catalysts include tertiary amines and dehydration catalysts. Preferred tertiary amines include heterocyclic tertiary amines, such as pyridine, picoline, quinoline, and isoquinoline. Examples of dehydration catalysts include acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride. While the reaction time for synthesizing polyamic acid resins and polyimide resins is significantly affected by the reaction temperature, it is preferable to carry out the reaction until the viscosity increase accompanying the reaction reaches equilibrium and the maximum molecular weight is obtained, which typically takes several minutes to 20 hours.

[0037] The above example is a method for synthesizing a polyimide resin via a polyamic acid. Alternatively, the polyimide resin of the present invention may be obtained by dissolving the components (A) and (B) used in the synthesis in a solvent, adding a dehydrating agent or catalyst as needed, and heating and stirring at 100 to 300°C to carry out the copolymerization reaction and the imidization reaction simultaneously.

[0038] Solvents that can be used in synthesizing the polyimide resin of the present invention include methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl butyl ketone, methyl isobutyl ketone, methyl n-hexyl ketone, diethyl ketone, diisopropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, acetylacetone, γ-butyrolactone, diacetone alcohol, cyclohexen-1-one, dipropyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran, tetrahydropyran, ethyl isoamyl ether, ethyl t-butyl ether, ethyl benzyl ether, cresyl methyl ether, anisole, phenetole, methyl acetate, ethyl acetate, propyl acetate, and isopropyl acetate. Examples of the solvent include, but are not limited to, methyl acetoacetate, butyl acetate, isobutyl acetate, amyl acetate, isoamyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, benzyl acetate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, butyl propionate, benzyl propionate, methyl butyrate, ethyl butyrate, isopropyl butyrate, butyl butyrate, isoamyl butyrate, methyl lactate, ethyl lactate, butyl lactate, ethyl isovalerate, isoamyl isovalerate, diethyl oxalate, dibutyl oxalate, methyl benzoate, ethyl benzoate, propyl benzoate, methyl salicylate, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide. These may be used alone or in combination of two or more.

[0039] The amount of solvent used during synthesis should be adjusted appropriately depending on the viscosity and use of the resulting resin, but the solid content is preferably 60 to 10 mass %, more preferably 50 to 20 mass %.

[0040] During synthesis of the polyimide resin of the present invention, it is preferable to use a catalyst to promote the dehydration reaction, and the amount of the catalyst used is preferably 1 to 30%, more preferably 5 to 15%, of twice the number of moles of the tetrabasic acid dianhydride (B) (the number of moles of water generated by dehydration condensation). Specific examples of catalysts that can be used include known general basic catalysts such as triethylamine and pyridine. Among these, triethylamine is preferred because of its low boiling point and low residue.

[0041] Next, the resin composition of the present invention will be described. The resin composition of the present invention contains the above-mentioned polyimide resin of the present invention and a thermosetting resin (C). Specific examples of the thermosetting resin (compound) contained in the resin composition of the present invention include epoxy resins, maleimide resins, carbodiimide resins, benzoxazine compounds, and compounds having an ethylenically unsaturated group, etc. These resins or compounds can be used alone or in appropriate mixtures of two or more types depending on the physical properties and applications of the resulting cured product. In the resin composition of the present invention, by using a thermosetting resin (compound) in combination with a polyimide resin, it is possible to impart thermal stability and high adhesiveness to the cured product of the resin composition.

[0042] The thermosetting resin (compound) contained in the resin composition of the present invention is preferably a maleimide resin or a compound having an ethylenically unsaturated group, since the cured product of the resin composition has particularly excellent heat resistance and adhesiveness. In addition, when the number of moles of component (A) used in the synthesis of the polyimide resin of the present invention is MA, the number of moles of component (B) is MB, the number of moles of thermosetting resin (C) is MC, and the number of moles of terminal functional groups of the polyimide resin of the present invention is MP, for polyimide resins in which the value of MA / MB exceeds 1 and the value of MC / MP is greater than 0 but less than 1, it is also preferable to use an epoxy resin as the thermosetting resin.

[0043] Furthermore, from the viewpoint of suppressing an increase in the viscosity of the varnish, the thermosetting resin (C) preferably has a molecular weight of 100 to 50,000. Note that the molecular weight in this specification means the weight average molecular weight of a polystyrene standard determined by gel permeation chromatography (GPC).

[0044] The maleimide resin as the thermosetting resin (C) is not particularly limited as long as it has two or more maleimide groups in one molecule. However, maleimide resins having an aromatic ring such as a benzene ring, a biphenyl ring, or a naphthalene ring are preferred because the cured product of the resin composition will have excellent properties such as mechanical strength and flame retardancy. Specific examples thereof include MIR-3000 (manufactured by Nippon Kayaku Co., Ltd.) and MIR-5000 (manufactured by Nippon Kayaku Co., Ltd.). The maleimide resin is added for the purpose of reacting with the ethylenically unsaturated double bond groups of the polyimide resin, thereby increasing the crosslink density of the cured product, improving resistance to polar solvents, and improving adhesion to substrates and heat resistance. The curing temperature of the resin composition containing the maleimide resin is preferably 150 to 250° C. The curing time depends on the curing temperature, but is generally from several minutes to several hours. The content of the maleimide resin in the resin composition of the present invention containing the maleimide resin is preferably an amount such that the number of maleimide group equivalents of the maleimide resin is 0.1 to 500 equivalents per equivalent of the ethylenically unsaturated double bond group of the polyimide resin.

[0045] To the resin composition of the present invention containing a maleimide resin, various radical initiators can be added as a curing agent (D) as needed for the purpose of accelerating the curing reaction of the maleimide resin. Examples of radical initiators include peroxides such as dicumyl peroxide and dibutyl peroxide, and azo compounds such as 2,2'-azobis(isobutyronitrile) and 2,2'-azobis(2,4-dimethylvaleronitrile). The amount of radical initiator added to the resin composition of the present invention containing a maleimide resin is 0.1 to 10% by mass relative to the maleimide resin.

[0046] The epoxy resin as the thermosetting resin (C) is not particularly limited as long as it has two or more epoxy groups in one molecule. However, since the cured product of the resin composition has excellent properties such as mechanical strength and flame retardancy, epoxy resins having an aromatic ring such as a benzene ring, a biphenyl ring, or a naphthalene ring are preferred, and specific examples thereof include jER828 (manufactured by Mitsubishi Chemical Corporation), NC-3000, and XD-1000 (all manufactured by Nippon Kayaku Co., Ltd.). The epoxy resin is added for the purpose of reacting with the terminal amino groups or acid anhydride groups of the polyimide resin, thereby increasing the crosslink density of the cured product, improving resistance to polar solvents, and improving adhesion to the substrate and heat resistance. The curing temperature of the resin composition containing the epoxy resin is preferably 150 to 250° C. The curing time depends on the curing temperature, but is generally from several minutes to several hours.

[0047] The content of the epoxy resin in the resin composition of the present invention containing an epoxy resin is preferably such that the epoxy group equivalent of the epoxy resin relative to 1 equivalent of the active hydrogen and acid anhydride in the phenolic hydroxyl group and terminal amino group of the polyimide resin is 0.1 to 500. Since the epoxy groups of the epoxy resin are reactive with the terminal functional groups of the polyimide resin, it is a preferred embodiment to add an epoxy resin in an amount such that the epoxy equivalent of the epoxy resin relative to 1 equivalent of the terminal functional group of the polyimide resin is 0.1 to 500 equivalents, as needed.

[0048] A curing agent (D) may be added to the resin composition of the present invention containing an epoxy resin, if necessary, to promote the curing reaction of the epoxy resin. Examples of the curing agent (D) include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole; tertiary amines such as 2-(dimethylaminomethyl)phenol and 1,8-diaza-bicyclo(5,4,0)undecene-7; phosphines such as triphenylphosphine; and metal compounds such as tin octoate. The amount of the curing agent (D) added to the resin composition of the present invention containing an epoxy resin is 0.1 to 10% by mass based on the epoxy resin.

[0049] The compound having an ethylenically unsaturated group as the thermosetting resin is not particularly limited as long as it has an ethylenically unsaturated group in one molecule. Specific examples of the compound having an ethylenically unsaturated group 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, tetrahydrofurfuryl (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, and polypropylene glycol di(meth)acrylate. , adipic acid epoxy di(meth)acrylate, bisphenol ethylene oxide di(meth)acrylate, hydrogenated bisphenol ethylene oxide (meth)acrylate, bisphenol di(meth)acrylate, ε-caprolactone-modified hydroxypivalic acid neopen glycol di(meth)acrylate, 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 ethylene oxide adducts thereof; pentaerythritol tri(meth)acrylate, and ethylene oxide adducts thereof; pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and ethylene oxide adducts thereof.

[0050] Other specific examples of the compound having an ethylenically unsaturated group include urethane (meth)acrylates having both a (meth)acryloyl group and a urethane bond in the same molecule; polyester (meth)acrylates having both a (meth)acryloyl group and an ester bond in the same molecule; epoxy (meth)acrylates derived from epoxy resins and having both a (meth)acryloyl group; and reactive oligomers in which these bonds are used in combination.

[0051] Examples of urethane (meth)acrylates include reaction products of a hydroxyl group-containing (meth)acrylate with a polyisocyanate and other alcohols used as needed. Examples 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; pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate; and the like. Examples of the urethane (meth)acrylates include those obtained by reacting sugar alcohol (meth)acrylates such as methyl methacrylate with polyisocyanates such as toluene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, xylene diisocyanate, hydrogenated xylene diisocyanate, dicyclohexanemethylene diisocyanate, and their isocyanurates and biuret reaction products.

[0052] 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; di(poly)ester (meth)acrylates such as hydroxypivalic acid ester neopentyl glycol di(meth)acrylate, caprolactone-modified hydroxypivalic acid 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 a cyclic lactone compound such as ε-caprolactone, γ-butyrolactone, or δ-valerolactone to 1 mole of trimethylolpropane or glycerin.

[0053] Other examples include 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, or mono(meth)acrylates or poly(meth)acrylates of polyhydric alcohols such as triols, tetraols, pentaols, or hexaols.

[0054] Further examples include polyfunctional (poly)ester (meth)acrylates such as (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 formed from diol components, polybasic acids, and their anhydrides with ε-caprolactone, γ-butyrolactone, δ-valerolactone, and the like.

[0055] Epoxy (meth)acrylates are carboxylate compounds of a compound having an epoxy group and (meth)acrylic acid. Examples include phenol novolac epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, trishydroxyphenylmethane epoxy (meth)acrylate, dicyclopentadienephenol epoxy (meth)acrylate, bisphenol A epoxy (meth)acrylate, bisphenol F epoxy (meth)acrylate, biphenol epoxy (meth)acrylate, bisphenol A novolac epoxy (meth)acrylate, naphthalene skeleton-containing epoxy (meth)acrylate, glyoxal epoxy (meth)acrylate, heterocyclic epoxy (meth)acrylate, and acid anhydride-modified epoxy acrylates thereof.

[0056] Specific examples of the compound having an ethylenically unsaturated group include vinyl ethers such as ethyl vinyl ether, propyl vinyl ether, hydroxyethyl vinyl ether, and ethylene glycol divinyl ether; styrenes such as styrene, methylstyrene, ethylstyrene, and divinylbenzene; and compounds having a vinyl group such as triallyl isocyanurate, trimethallyl isocyanurate, and bisallylnadimide.

[0057] The compound having an ethylenically unsaturated group may be a commercially available product, such as KAYARAD (registered trademark) ZCA-601H (trade name, manufactured by Nippon Kayaku Co., Ltd.), propylene glycol monomethyl ether acetate of TrisP-PA epoxy acrylate compound (manufactured by Nippon Kayaku Co., Ltd., KAYARAD (registered trademark) ZCR-6007H (trade name), KAYARAD (registered trademark) ZCR-6001H (trade name), KAYARAD (registered trademark) ZCR-6002H (trade name), KAYARAD (registered trademark) ZCR-6006H (trade name), and KAYARAD (registered trademark) ZXR-1889H (trade name, manufactured by Nippon Kayaku Co., Ltd.). These compounds having an ethylenically unsaturated group may be used alone or in appropriate mixtures of two or more types.

[0058] The content of the compound having an ethylenically unsaturated group in the resin composition of the present invention containing the compound having an ethylenically unsaturated group is preferably an amount that is 0.1 to 500 equivalents relative to the equivalent weight of the ethylenically unsaturated double bond group of the polyimide resin.

[0059] To the resin composition of the present invention containing a compound having an ethylenically unsaturated group, a curing agent (D) such as a radical initiator can be added as needed to promote the curing reaction between the polyimide resin and the ethylenically unsaturated group. Specific examples of radical initiators include peroxides such as dicumyl peroxide and dibutyl peroxide, and azo compounds such as 2,2'-azobis(isobutyronitrile) and 2,2'-azobis(2,4-dimethylvaleronitrile). The amount of radical initiator added to the resin composition of the present invention containing a compound having an ethylenically unsaturated group is 0.1 to 10% by mass based on the ethylenically unsaturated group in the entire composition.

[0060] The resin composition of the present invention can be used in combination with an organic solvent to form a varnish-like composition (hereinafter simply referred to as "varnish"). Examples of solvents that can be used include amide-based solvents such as γ-butyrolactones, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and N,N-dimethylimidazolidinone, sulfones such as tetramethylene sulfone, ether-based 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-based solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone, and aromatic solvents such as toluene and xylene. The organic solvent is used in such a range that the solids concentration excluding the organic solvent in the varnish is preferably 10 to 80% by mass, more preferably 20 to 70% by mass.

[0061] The resin composition of the present invention may be used in combination with known additives as necessary.Specific examples of the additives that can be used in combination include epoxy resin curing agents, polybutadiene or its modified products, modified acrylonitrile copolymers, polyphenylene ether, polystyrene, polyethylene, polyimide, fluororesin, maleimide compounds, cyanate ester compounds, silicone gel, silicone oil, and inorganic fillers such as silica, alumina, calcium carbonate, quartz powder, aluminum powder, graphite, talc, clay, iron oxide, titanium oxide, aluminum nitride, asbestos, mica, and glass powder, surface treatment agents for fillers such as silane coupling agents, release agents, colorants such as carbon black, phthalocyanine blue, and phthalocyanine green, thixotropy-imparting agents such as Aerosil, silicone-based and fluorine-based leveling agents and antifoaming agents, hydroquinone, hydroquinone monomethyl ether, phenol-based polymerization inhibitors, stabilizers, antioxidants, photopolymerization initiators, photobase generators, and photoacid generators. The amount of these additives to be 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 resin composition. As the additive, a silane coupling agent having an acrylic group or a methacrylic group is particularly preferred from the viewpoint of heat resistance.

[0062] The method for preparing the resin composition of the present invention is not particularly limited, and the components may be simply mixed uniformly, or may be prepolymerized. For example, the polyimide resin or terminal-modified polyimide resin of the present invention and a reactive compound may be heated in the presence or absence of a catalyst and in the presence or absence of a solvent to form a prepolymer. For mixing or prepolymerization of the components, an extruder, kneader, rolls, or the like may be used in the absence of a solvent, and a reactor equipped with a stirrer may be used in the presence of a solvent.

[0063] The resin composition of the present invention can be cured by heating. The curing temperature and curing time of the resin composition may be selected taking into consideration the combination of the functional groups of the polyimide resin of the present invention and the reactive groups of the thermosetting resin. For example, the curing temperature of a resin composition containing a maleimide resin or a resin composition containing an epoxy resin is preferably 120 to 250°C, and the curing time is generally from several tens of minutes to several hours.

[0064] A prepreg can be obtained by heating and melting the resin composition of the present invention to reduce the viscosity and impregnating it into reinforcing fibers such as glass fibers, carbon fibers, polyester fibers, polyamide fibers, alumina fibers, etc. Alternatively, a prepreg can be obtained by impregnating reinforcing fibers with the varnish and drying them by heating. The prepreg is cut into a desired shape and laminated with copper foil or the like as needed. The resin composition is then heated and cured while applying pressure to the laminate using a press molding method, autoclave molding method, sheet winding molding method or the like, to obtain a substrate (article) comprising the cured product of the present invention, such as an electrical and electronic laminate (printed wiring board) or a carbon fiber reinforced material. Alternatively, a substrate having the cured product of the present invention can be obtained by coating a copper foil, drying the solvent, laminating a polyimide film or LCP (liquid crystal polymer), hot pressing, and then heat curing. In some cases, a substrate having the cured product of the present invention can be obtained by coating a polyimide film or LCP side and laminating it with copper foil. Furthermore, a substrate having the cured product of the present invention can also be obtained by coating the resin composition of the present invention on copper foil, drying the solvent, and then laminating a prepreg in which the resin is impregnated into reinforcing fibers such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, or alumina fiber, and then heat-pressing and curing the prepreg.

[0065] The substrate comprising the polyimide resin of the present invention can be used for copper clad laminates (CCL), or printed wiring boards and multilayer wiring boards having a circuit pattern on the copper foil of the CCL. [Example]

[0066] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples, "parts" means parts by mass, and "%" means % by mass. The GPC measurement conditions in the examples are as follows: Model: TOSOH ECOSEC Elite HLC-8420GPC Column: TSKgel Super AWM-H Eluent: NMP (N-methylpyrrolidone); 0.5 ml / min, 40°C Detector: UV (differential refractometer) Molecular weight standard: polystyrene

[0067] Example 1 (Synthesis of Polyimide Resin 1 of the Present Invention) A 300 ml reactor equipped with a thermometer, reflux condenser, Dean-Stark apparatus, powder inlet, nitrogen inlet, and stirrer was charged with 11.70 parts of Diamine H20 (Okamura Oil Mills, molecular weight 325.09 g / mol), 7.76 parts of BAFL (9,9-bis(4-aminophenyl)fluorene, JFE Chemical Corporation, molecular weight 348.16 g / mol), and 65.17 parts of anisole, and heated to 70 ° C. Next, 14.33 parts of ODPA (oxydiphthalic anhydride, Manac Corporation, molecular weight 310.22 g / mol), 0.95 parts of triethylamine, and 14.77 parts of toluene were added, and the reaction was continued for 8 hours at 130 ° C. while removing the water generated by the ring closure of the amic acid by azeotropy with toluene to obtain a polyimide resin 1 solution (polyimide resin molecular weight 62,000). The molar ratio of the amino compound (A) to the tetrabasic acid dianhydride (B) (number of moles of diamine component / number of moles of acid anhydride component) was 1.02.

[0068] Example 2 (Synthesis of Polyimide Resin 2 of the Present Invention) A 300 ml reactor equipped with a thermometer, a reflux condenser, a Dean-Stark apparatus, a powder inlet, a nitrogen introducing apparatus, and a stirrer was charged with 10.33 parts of Diamine H20 (manufactured by Okamura Oil Mills, Ltd., molecular weight 325.09 g / mol), 2.56 parts of BAFL (9,9-bis(4-aminophenyl)fluorene, manufactured by JFE Chemical Corporation, molecular weight 348.16 g / mol), 2.64 parts of PRIAMINE1075 (manufactured by Croda Japan, molecular weight 534.38 g / mol), and 66.45 parts of anisole, and the mixture was heated to 70°C. Next, 14.33 parts of ODPA (oxydiphthalic anhydride, manufactured by Manac Corporation, molecular weight 310.22 g / mol), 0.93 parts of triethylamine, and 14.86 parts of toluene were added, and the mixture was reacted at 130°C for 8 hours while removing water generated by ring closure of the amic acid via azeotropy with toluene, to obtain a polyimide resin 2 solution (polyimide resin molecular weight 41,000). The molar ratio of the amino compound (A) to the tetrabasic acid dianhydride (B) (number of moles of diamine component / number of moles of acid anhydride component) was 1.02.

[0069] Example 3 (Synthesis of Polyimide Resin 3 of the Present Invention) A 300 ml reactor equipped with a thermometer, reflux condenser, Dean-Stark apparatus, powder inlet, nitrogen inlet, and stirrer was charged with 11.68 parts of Diamine H20 (Okamura Oil Mills, molecular weight 325.09 g / mol), 7.76 parts of BAPP (2,2-bis(4-(4-aminophenoxy)phenyl)propane, Wakayama Seika Co., Ltd., molecular weight 410.52 g / mol), and 66.13 parts of anisole, and heated to 70 ° C. Next, 14.33 parts of ODPA (oxydiphthalic anhydride, Manac Corporation, molecular weight 310.22 g / mol), 0.94 parts of triethylamine, and 14.36 parts of toluene were added, and the reaction was continued for 8 hours at 130 ° C. while removing the water generated by the ring closure of the amic acid azeotropically with toluene to obtain a polyimide resin 3 solution (polyimide resin molecular weight 43,000). The molar ratio of the amino compound (A) to the tetrabasic acid dianhydride (B) (number of moles of diamine component / number of moles of acid anhydride component) was 1.02.

[0070] Comparative Example 1 (Synthesis of Comparative Polyimide Resin 1) A 300 ml reactor equipped with a thermometer, reflux condenser, Dean-Stark apparatus, powder inlet, nitrogen inlet, and stirrer was charged with 11.70 parts of PRIAMINE 1075 (manufactured by Croda Japan Co., Ltd., molecular weight 534.38 g / mol), 7.77 parts of BAFL (9,9-bis(4-aminophenyl)fluorene, manufactured by JFE Chemical Corporation, molecular weight 348.16 g / mol), and 75.25 parts of anisole, and heated to 70 ° C. Next, 14.33 parts of ODPA (oxydiphthalic anhydride, manufactured by Manac Corporation, molecular weight 310.22 g / mol), 0.94 parts of triethylamine, and 15.74 parts of toluene were added, and the mixture was reacted at 130 ° C. for 8 hours while azeotropically removing water generated by the ring closure of the amic acid with toluene to obtain a comparative polyimide resin 1 solution (polyimide resin molecular weight 37,000).

[0071] Comparative Example 2 (Synthesis of Comparative Polyimide Resin 2) A 300 ml reactor equipped with a thermometer, reflux condenser, Dean-Stark apparatus, powder inlet, nitrogen inlet, and stirrer was charged with 11.70 parts of 1,10-decanediamine (Tokyo Chemical Industry Co., Ltd., molecular weight 172.32 g / mol), 7.77 parts of BAFL (9,9-bis(4-aminophenyl)fluorene, JFE Chemical Corporation, molecular weight 348.16 g / mol), and 75.25 parts of anisole, and heated to 70 ° C. Next, 14.33 parts of ODPA (oxydiphthalic anhydride, Manac Corporation, molecular weight 310.22 g / mol), 0.94 parts of triethylamine, and 15.74 parts of toluene were added, and the mixture was reacted at 130 ° C. for 8 hours while azeotropically removing water generated by the ring closure of the amic acid with toluene to obtain a comparative polyimide resin 2 solution (polyimide resin molecular weight 37,000).

[0072] Examples 4 to 9 and Comparative Examples 3 and 4 (Preparation of Resin Compositions of the Present Invention and Comparative Examples) The components were blended in the amounts shown in Table 1 (unit: "parts," the numbers in the table being the number of parts converted to solid content excluding solvent), and then anisole was added as a solvent in an amount to give a solid content concentration of 20 mass %, and the mixture was mixed uniformly to prepare the resin compositions of the present invention and the comparative examples.

[0073] The components in Table 1 are as follows: <Polyimide resin> (A-1) to (A-3) Polyimide resins 1 to 3 of the present invention obtained in Examples 1 to 3 (A-4) and (A-5) are comparative polyimide resins 1 and 2 obtained in Comparative Examples 1 and 2. <Thermosetting resin> MIR-3000-70MT: Maleimide resin, manufactured by Nippon Kayaku Co., Ltd. XD-1000: Epoxy resin, manufactured by Nippon Kayaku Co., Ltd. ZXR-1889H: Epoxy acrylate resin, manufactured by Nippon Kayaku Co., Ltd. <Curing agent> DCP: Dicumyl peroxide, manufactured by Kayaku Nouryon Co., Ltd. <Additives> KR-513: Silane coupling agent, manufactured by Shin-Etsu Chemical Co., Ltd.

[0074] Using each of the resin compositions obtained in Examples 4 to 9 and Comparative Examples 3 and 4, the adhesive strength to copper foil, thermal properties, storage stability, and dielectric properties (dielectric constant and dielectric loss tangent) of the cured resin compositions were evaluated by the following methods.

[0075] (Evaluation of adhesive strength) The resin compositions of Examples 14 to 9 and Comparative Examples 3 and 4 were applied to the rough surface of ultra-low roughness, non-roughened electrolytic copper foil CF-T49A-DS-HD (hereafter referred to as "T49A") manufactured by Fukuda Metal Foil & Powder Co., Ltd. using an automatic applicator in an amount such that the resin composition layer would have a thickness of 30 μm after application and drying, and then heated and dried at 120°C for 10 minutes. Kapton 20EN (manufactured by DuPont-Toray Co., Ltd.) was placed on the resulting resin composition layer on the copper foil, and the resulting layer was vacuum-pressed at 200°C for 60 minutes under 3 MPa. The resulting test specimens were cut to a width of 10 mm, and the 90° peel strength (peel speed: 50 mm / min) between the copper foil and the cured resin composition layer was measured using an autograph AGS-X-500N (manufactured by Shimadzu Corporation). The results are shown in Table 1.

[0076] (Evaluation of thermal properties) Test pieces prepared in the same manner as in the "Evaluation of Adhesion Strength" above were floated in a solder bath heated to 288°C using a POT-200C (manufactured by Taiyo Electric Industry Co., Ltd.), and the time until blisters appeared was measured. The thermal properties were evaluated according to the following criteria. The results are shown in Table 1. ◎ No swelling over 600 ○ Blisters occur between 10 seconds and 600 seconds × Blisters appear in less than 10 seconds

[0077] (Evaluation of Coatability) For test pieces prepared in the same manner as in the "Evaluation of Adhesion Strength" above, voids (air bubbles) contained in the recesses of the roughened copper foil surface were confirmed using an optical microscope. Depending on the percentage of recesses where voids were observed, the coatability on the rough surface was evaluated according to the following criteria. ○ The percentage of concave portions where voids were observed was 0% or more but less than 1% △: The percentage of concave portions where voids were observed was 1% or more but less than 2% × The percentage of concave portions where voids were observed is 2% or more

[0078] (Evaluation of dielectric constant and dielectric loss tangent) The same method as described above for "Evaluation of Adhesion Strength" was used to form a coating of the resin composition on the rough surface of T49A, except that the amount of resin composition applied was changed to an amount that would result in a resin composition layer thickness of 100 μm after drying. The coating was then heat-cured at 200°C for 60 minutes. The copper foil was etched away from the resulting laminate of the cured resin composition layer and copper foil using an iron(III) chloride solution with a liquid specific gravity of 45 Baume. The resulting laminate was washed with ion-exchanged water and dried at 105°C for 10 minutes to obtain a film-like cured resin composition. The stress at break, elongation at break, and modulus of elasticity of the cured film were measured using an Autograph AGS-X-500N (Shimadzu Corporation), and the dielectric constant and dielectric loss tangent at 10 GHz were measured using a network analyzer 8719ET (Agilent Technologies) by cavity resonance. The results are shown in Table 1.

[0079] [Table 1]

[0080] The results in Table 1 show that the resin compositions containing the polyimide resins of the present invention are excellent in all of adhesive strength, heat resistance, coatability, and dielectric properties, whereas the resin compositions of the comparative examples are inferior in adhesive strength, heat resistance, and varnish storage stability. [Industrial Applicability]

[0081] By using the polyimide resin having the specific structure of the present invention, heat resistance, mechanical properties, low dielectric properties, It is possible to provide a printed wiring board or the like having excellent properties such as adhesiveness.

Claims

1. The polyimide resin is a copolymer of an amino compound (A) and a tetrabasic acid dianhydride (B), the amino compound (A) including a linear aliphatic diamino compound (a1) and an aromatic diamino compound (a2), each having amino groups at both ends and 1 to 4 methyl and / or ethyl groups in its side chain, and each having 17 to 24 carbon atoms in its main chain.

2. The tetrabasic acid dianhydride (B) is represented by the following formulas (1) to (9): 【Chemical 1】 (In formula (4), Y is C(CF ３ ) ２ , S.O. ２ , CO, an oxygen atom, a direct bond, or the following formula (10): 【Chemistry 2】 represents a divalent linking group represented by the formula: The polyimide resin according to claim 1, comprising a compound selected from the group consisting of:

3. The aromatic diamino compound (a2) is represented by the following formulas (11) to (14): 【Chemistry 3】 (In formula (13), R ２ independently represent a methyl group or a trifluoromethyl group, and in formula (14), Z is CH(CH ３ ), SO ２ , C.H. ２ , O-C ６ H ４ -O, an oxygen atom, a direct bond, or the following formula (10) 【Chemistry 4】 and a divalent linking group represented by R ３ and (iii) independently represent a hydrogen atom, a methyl group, an ethyl group, or a trifluoromethyl group.

4. A resin composition comprising the polyimide resin according to claim 1 and a thermosetting resin (C).

5. The resin composition according to claim 4, wherein the thermosetting resin (C) is a maleimide resin.

6. The resin composition according to claim 4 or 5, further comprising a radical initiator as a curing agent.

7. A cured product of the resin composition according to any one of claims 4 to 6.

8. An article comprising the cured product according to claim 7.

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