Curable resin composition, cured product, adhesive, and adhesive film

Abstract

The purpose of the present invention is to provide a curable resin composition that has excellent heat resistance, thermal conductivity, and adhesiveness. Another purpose of the present invention is to provide a cured product of said curable resin composition, as well as an adhesive agent and adhesive film which are obtained by using said curable resin composition. The present invention is a curable resin composition containing a curable resin, a curing agent, and a thermally conductive filler, wherein the curing agent includes an imide oligomer and the thermal conductivity of the curable resin composition after being cured is 1 W / mK or more.

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition that is excellent in heat resistance, thermal conductivity, and adhesiveness. The present invention also relates to a cured product of the curable resin composition, and to an adhesive and adhesive film made using the curable resin composition. [Background technology]

[0002] As a method for dissipating heat from electronic components, a heat dissipation material is generally used to prevent heat generated by the electronic component from accumulating in the electronic component. As such a heat dissipation material, adhesives using curable resin compositions with excellent thermal conductivity and heat resistance are being considered. As curable resin compositions with excellent thermal conductivity and heat resistance, for example, Patent Document 1 discloses an adhesive composition having an epoxy resin and a siloxane-modified polyamide-imide component, and Patent Document 2 discloses a curable resin composition containing a polyimide silicone resin having two or more phenolic hydroxyl groups in one molecule and an epoxy resin. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2003-193016 [Patent Document 2] Japanese Patent Publication No. 2005-113059 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] When conventional curable resin compositions disclosed in Patent Documents 1 and 2 were used as adhesives for electronic components, problems such as poor contact could occur due to the adhesion of low molecular weight siloxane compounds derived from these compositions to the electronic components. In contrast, while non-silicone materials do not present the aforementioned problems, it is difficult to obtain materials that fully satisfy the requirements for heat resistance, thermal conductivity, and adhesion. The present invention aims to provide a curable resin composition that exhibits excellent heat resistance, thermal conductivity, and adhesive properties. Furthermore, the present invention aims to provide a cured product of the curable resin composition, as well as an adhesive and adhesive film made using the curable resin composition. [Means for solving the problem]

[0005] Disclosure 1 This is a curable resin composition comprising a curable resin, a curing agent, and a thermally conductive filler, wherein the curing agent comprises an imide oligomer, and the curable resin composition has a thermal conductivity of 1 W / m·K or more after curing. Disclosure 2 is a curable resin composition of Disclosure 1 in which the curable resin and curing agent described above do not contain compounds having a siloxane skeleton. Disclosure 3 is a curable resin composition according to Disclosure 1 or 2, wherein the curable resin comprises at least one selected from the group consisting of epoxy resin, cyanate resin, maleimide resin, and benzoxazine resin. Disclosure 4 is a curable resin composition of Disclosure 1, 2, or 3, wherein the molecular weight of the imide oligomer is 5000 or less. Disclosure 5 is a curable resin composition of Disclosure 1, 2, 3, or 4 in which the imide oligomer has reactive functional groups that can react with the curable resin. Disclosure 6 is a curable resin composition of Disclosure 5, wherein the reactive functional group is at least one selected from the group consisting of an acid anhydride group, a phenolic hydroxyl group, and an amino group. Disclosure 7 is a curable resin composition of Disclosure 1, 2, 3, 4, 5, or 6, wherein the thermally conductive filler comprises at least one selected from the group consisting of alumina, aluminum nitride, silicon carbide, boron nitride, silicon nitride, magnesium oxide, zinc oxide, boron carbide, titanium carbide, zirconia, aluminum, and diamond. Disclosure 8 is a curable resin composition according to Disclosure 1, 2, 3, 4, 5, 6, or 7, wherein the content of the above-mentioned thermal conductive filler in the curable resin composition (excluding the solvent) is 50% by volume or more. Disclosure 9 is a curable resin composition of Disclosure 1, 2, 3, 4, 5, 6, 7, or 8, wherein the curable resin composition further contains a polymer component, and the polymer component has a number average molecular weight of 5000 or more. Disclosure 10 is a curable resin composition of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, or 9 that does not contain a compound having an amide skeleton. Disclosure 11 is a curable resin composition of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, wherein the shear adhesion strength of the cured product to aluminum is 4 MPa or more. Disclosure 12 is a curable resin composition of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11, wherein the temperature at which the 1% weight loss after curing is 350°C or higher. Disclosure 13 is a cured product of a curable resin composition of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12. Disclosure 14 is an adhesive made using the curable resin composition of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12. Disclosure 15 is an adhesive film made using the cured product of Disclosure 13 or the adhesive of Disclosure 14. The present invention will be described in detail below.

[0006] The present inventors have discovered that a curable resin composition with excellent heat resistance, thermal conductivity, and adhesive properties can be obtained by further incorporating a thermally conductive filler into a curable resin composition containing a curable resin and an imide oligomer as a curing agent, so that the thermal conductivity of the cured curable resin composition becomes 1 W / m·K or higher, thereby completing the present invention.

[0007] The curable resin composition of the present invention has a lower limit of 1 W / m·K in thermal conductivity after curing. Because the above-mentioned thermal conductivity after curing is 1 W / m·K or higher, the curable resin composition of the present invention can be suitably used as a heat-dissipating adhesive. A preferred lower limit for the above-mentioned thermal conductivity after curing is 1.5 W / m·K, and a more preferred lower limit is 2 W / m·K. Furthermore, while there is no particular preferred upper limit for the thermal conductivity after curing, the practical upper limit is 20 W / m·K. The above thermal conductivity can be measured at 23°C according to ASTM D5470. Examples of measuring devices used for measuring the above thermal conductivity include the "T3Ster DynTIM Tester" from Mentor, a Siemens Business. Furthermore, the cured material used for measuring the above thermal conductivity is obtained by drying a curable resin composition and then curing it by heating it at 190°C for 1 hour.

[0008] The curable resin composition of the present invention contains a curable resin. Examples of the curable resins mentioned above include epoxy resins, cyanate resins, phenolic resins, polyimide resins, maleimide resins, benzoxazine resins, silicone resins, acrylic resins, and fluororesins. In particular, the curable resin preferably contains at least one selected from the group consisting of epoxy resins, cyanate resins, maleimide resins, and benzoxazine resins, and more preferably contains epoxy resin. The curable resins may be used individually or in combination of two or more types.

[0009] Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, 2,2'-diallylbisphenol A type epoxy resin, hydrogenated bisphenol type epoxy resin, propylene oxide-added bisphenol A type epoxy resin, resorcinol type epoxy resin, biphenyl type epoxy resin, sulfide type epoxy resin, diphenyl ether type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, naphthylene ether type epoxy resin, phenol novolak type epoxy resin, ortho-cresol novolak type epoxy resin, dicyclopentadiene novolak type epoxy resin, biphenyl novolak type epoxy resin, naphthalene phenol novolak type epoxy resin, glycidylamine type epoxy resin, alkyl polyol type epoxy resin, rubber-modified type epoxy resin, glycidyl ester compound, etc. Among them, an epoxy resin that is liquid at 25°C is preferable because it has a low viscosity and it is easy to adjust the workability of the resulting curable resin composition. The above epoxy resin may be used alone or in combination of two or more kinds.

[0010] As described later, it is preferable that the curable resin does not contain a compound having a siloxane skeleton.

[0011] The curable resin composition of the present invention further contains a curing agent. The above curing agent contains an imide oligomer. By using the above imide oligomer as the above curing agent, the cured product of the curable resin composition of the present invention has excellent heat resistance.

[0012] It is preferable that the above imide oligomer has a reactive functional group capable of reacting with the above curable resin. The above-mentioned reactive functional group depends on the type of curable resin used, but when epoxy resin is used as the curable resin, it is preferable that it be at least one selected from the group consisting of acid anhydride groups, phenolic hydroxyl groups, and amino groups. Among these, acid anhydride groups or phenolic hydroxyl groups are particularly preferred from the viewpoint of storage stability and heat resistance. The above-mentioned imide oligomer preferably has the above-mentioned reactive functional group at the end of the main chain, and more preferably has it at both ends of the main chain.

[0013] The above-mentioned imide oligomer preferably has a structure represented by the following formula (1-1) or formula (1-2), or by the following formula (2-1) or formula (2-2). By having a structure represented by the following formula (1-1) or formula (1-2), or by the following formula (2-1) or formula (2-2), the above-mentioned imide oligomer exhibits superior reactivity and compatibility with the above-mentioned curable resin.

[0014] [ka]

[0015] In formulas (1-1) and (1-2), A is an acid dianhydride residue, in formula (1-1), B is an aliphatic diamine residue or an aromatic diamine residue, and in formula (1-2), Ar is an optionally substituted divalent aromatic group.

[0016] [ka]

[0017] In formulas (2-1) and (2-2), A is an acid dianhydride residue, B is an aliphatic triamine residue or an aromatic triamine residue, and in formula (2-2), Ar is an optionally substituted divalent aromatic group.

[0018] The above acid dianhydride residue is preferably a tetravalent group represented by the following formula (3-1) or formula (3-2).

[0019] [ka]

[0020] In formulas (3-1) and (3-2), * represents a bond position, and in formula (3-1), Z is a bond, an oxygen atom, a carbonyl group, a sulfur atom, a sulfonyl group, a linear or branched divalent hydrocarbon group, or a divalent group having an aromatic ring. When Z is a hydrocarbon group, there may be an oxygen atom between the hydrocarbon group and each aromatic ring in formula (3-1), and when Z is a divalent group having an aromatic ring, there may be an oxygen atom between the divalent group having an aromatic ring and each aromatic ring in formula (3-1). The hydrogen atoms of the aromatic rings in formulas (3-1) and (3-2) may be substituted.

[0021] In formula (3-1) above, if Z is a linear or branched divalent hydrocarbon group, or a divalent group having an aromatic ring, these groups may be substituted. Examples of substituents when the above-mentioned linear or branched divalent hydrocarbon group, or the above-mentioned divalent group having an aromatic ring, is substituted include halogen atoms, linear or branched alkyl groups, linear or branched alkenyl groups, alicyclic groups, aryl groups, alkoxy groups, nitro groups, cyano groups, and the like.

[0022] Examples of acid dianhydrides from which the above-mentioned acid dianhydride residues originate include the acid dianhydride represented by formula (9) described later.

[0023] When B in formula (1-1) is the aliphatic diamine residue, or when B in formula (2-1) or formula (2-2) is the aliphatic triamine residue, the preferred lower limit for the number of carbon atoms in the aliphatic diamine residue and the aliphatic triamine residue is 4. Having 4 or more carbon atoms in the aliphatic diamine residue and the aliphatic triamine residue results in a curable resin composition that is superior in flexibility and processability before curing, and in dielectric properties after curing. A more preferred lower limit for the number of carbon atoms in the aliphatic diamine residue and the aliphatic triamine residue is 5, and an even more preferred lower limit is 6. Furthermore, there is no particular preferred upper limit for the number of carbon atoms in the above-mentioned aliphatic diamine residue and aliphatic triamine residue, but the practical upper limit is 60.

[0024] Examples of aliphatic diamines from which the above-mentioned aliphatic diamine residues are derived include aliphatic diamines derived from dimer acids, linear or branched aliphatic diamines, aliphatic ether diamines, and aliphatic alicyclic diamines. Examples of aliphatic diamines derived from the above-mentioned dimer acids include dimer amines and hydrogenated dimer amines. Examples of the above-mentioned linear or branched aliphatic diamines include 1,4-butanediamine, 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1,16-hexadecanediamine, 1,18-octadecanediamine, 1,20-eicosanediamine, 2-methyl-1,8-octanediamine, 2-methyl-1,9-nonanediamine, and 2,7-dimethyl-1,8-octanediamine. Examples of the above-mentioned aliphatic ether diamines include 2,2'-oxybis(ethylamine), 3,3'-oxybis(propylamine), and 1,2-bis(2-aminoethoxy)ethane. Examples of the above-mentioned aliphatic alicyclic diamines include 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, cyclohexanediamine, methylcyclohexanediamine, and isophoronediamine. In particular, the aliphatic diamine residue is preferably an aliphatic diamine residue derived from the dimer acid.

[0025] Examples of aliphatic triamines from which the above-mentioned aliphatic triamine residues are derived include aliphatic triamines derived from trimer acids, linear or branched aliphatic triamines, aliphatic ether triamines, and aliphatic alicyclic triamines. Examples of aliphatic triamines derived from the above-mentioned trimer acids include trimer triamines and hydrogenated trimer triamines. Examples of the linear or branched aliphatic triamines mentioned above include 3,3'-diamino-N-methyldipropylamine, 3,3'-diaminodipropylamine, diethylenetriamine, bis(hexamethylene)triamine, and 2,2'-bis(methylamino)-N-methyldiethylamine. In particular, the aliphatic triamine residue is preferably an aliphatic triamine residue derived from the trimer acid.

[0026] Furthermore, a mixture of the dimer amine and trimer triamine may be used as the aliphatic diamine and / or aliphatic triamine.

[0027] Examples of commercially available aliphatic diamines and / or aliphatic triamines derived from the above-mentioned dimer acids and / or trimer acids include aliphatic diamines and / or aliphatic triamines manufactured by BASF and aliphatic diamines and / or aliphatic triamines manufactured by Croda. Examples of the aliphatic diamines and / or aliphatic triamines manufactured by BASF include Versamin 551 and Versamin 552. Examples of the aliphatic diamines and / or aliphatic triamines manufactured by Croda include Priamine 1071, Priamine 1073, Priamine 1074, and Priamine 1075.

[0028] When B in formula (1-1) above is the aromatic diamine residue, it is preferable that the aromatic diamine residue is a divalent group represented by the following formula (4-1) or formula (4-2).

[0029] [ka]

[0030] In formulas (4-1) and (4-2), * represents a bond position, and in formula (4-1), Y is a bond, an oxygen atom, a carbonyl group, a sulfur atom, a sulfonyl group, a linear or branched divalent hydrocarbon group, or a divalent group having an aromatic ring. When Y is a hydrocarbon group, there may be an oxygen atom between the hydrocarbon group and each aromatic ring in formula (4-1), and when Y is a divalent group having an aromatic ring, there may be an oxygen atom between the divalent group having an aromatic ring and each aromatic ring in formula (4-1). The hydrogen atoms of the aromatic rings in formulas (4-1) and (4-2) may be substituted.

[0031] In formula (4-1) above, if Y is a linear or branched divalent hydrocarbon group, or a divalent group having an aromatic ring, these groups may be substituted. Examples of substituents when the above-mentioned linear or branched divalent hydrocarbon group, or the above-mentioned divalent group having an aromatic ring, is substituted include halogen atoms, linear or branched alkyl groups, linear or branched alkenyl groups, alicyclic groups, aryl groups, alkoxy groups, nitro groups, cyano groups, and the like.

[0032] Examples of aromatic diamines from which the above aromatic diamine residues originate include cases where the diamine represented by formula (10), described later, is an aromatic diamine.

[0033] As described later, the curing agent described above preferably does not contain a compound having a siloxane skeleton. In particular, if the imide oligomer has a siloxane skeleton in its structure, it may lower the glass transition temperature of the cured product of the curable resin composition, contaminate the adherend, and cause poor adhesion. Therefore, it is preferable that the imide oligomer does not have a siloxane skeleton in its structure.

[0034] The molecular weight of the above imide oligomer is preferably 5000 or less. A molecular weight of 5000 or less of the above imide oligomer results in a cured product of the resulting curable resin composition exhibiting superior long-term heat resistance. A more preferable upper limit for the molecular weight of the above imide oligomer is 4000, and an even more preferable upper limit is 3000. In particular, the molecular weight of the imide oligomer is preferably 900 to 5000 when it has the structure represented by formula (1-1) or formula (2-1), and preferably 550 to 4000 when it has the structure represented by formula (1-2) or formula (2-2). A more preferred lower limit for the molecular weight when it has the structure represented by formula (1-1) or formula (2-1) is 950, and an even more preferred lower limit is 1000. A more preferred lower limit for the molecular weight when it has the structure represented by formula (1-2) or formula (2-2) is 580, and an even more preferred lower limit is 600. In this specification, the "molecular weight" refers to the molecular weight determined from the structural formula for compounds whose molecular structure is specified. However, for compounds with a wide distribution of polymerization degrees and compounds with unspecified modification sites, the number-average molecular weight may be used. Furthermore, the "number-average molecular weight" is determined by measuring it using gel permeation chromatography (GPC) with tetrahydrofuran as the solvent and converting it to polystyrene equivalent. Examples of columns used when measuring the number-average molecular weight in polystyrene equivalent by GPC include JAIGEL-2H-A (manufactured by Nippon Analytical Engineering Co., Ltd.).

[0035] The above-mentioned imide oligomer is preferably an imide oligomer represented by the following formula (5-1), (5-2), (5-3), (5-4), or (5-5), or an imide oligomer represented by the following formula (6-1), (6-2), (6-3), (6-4), (6-5), or (6-6).

[0036] [ka]

[0037] In formulas (5-1) to (5-5), A is the above-mentioned acid dianhydride residue, and in formulas (5-1) to (5-5), A may be the same or different in each case. In formulas (5-1) to (5-4), B is the above-mentioned aliphatic diamine residue or the above-mentioned aromatic diamine residue, and in formulas (5-3) and (5-4), B may be the same or different in each case. In formula (5-5), B is the above-mentioned aliphatic triamine residue or the above-mentioned aromatic triamine residue. In formula (5-2), X is a hydrogen atom, a halogen atom, or an optionally substituted monovalent hydrocarbon group, and in formula (5-4), W is a hydrogen atom, a halogen atom, or an optionally substituted monovalent hydrocarbon group. In formulas (5-3) and (5-4), n is the number of repetitions.

[0038] [ka]

[0039] In formulas (6-1) to (6-6), A is the above-mentioned acid dianhydride residue, and A in formulas (6-1) to (6-6) may be the same or different. In formulas (6-1) to (6-6), R is a hydrogen atom, a halogen atom, or an optionally substituted monovalent hydrocarbon group, and R in formulas (6-1), (6-2), (6-4), and (6-6) may be the same or different. In formulas (6-3) and (6-5), W is a hydrogen atom, a halogen atom, or an optionally substituted monovalent hydrocarbon group. In formulas (6-2) to (6-4), B is the above-mentioned aliphatic diamine residue or aromatic diamine residue, and B in formulas (6-4) and (6-5) may be the same or different. In formula (6-6), B is either the above-mentioned aliphatic triamine residue or the above-mentioned aromatic triamine residue.

[0040] In the above formulas (5-1) to (5-5) and (6-1) to (6-6), A is preferably a tetravalent group represented by the following formula (7-1) or formula (7-2).

[0041] [ka]

[0042] In formulas (7-1) and (7-2), * represents a bond position, and in formula (7-1), Z is a bond, an oxygen atom, a carbonyl group, a sulfur atom, a sulfonyl group, a linear or branched divalent hydrocarbon group, or a divalent group having an aromatic ring. When Z is a hydrocarbon group, there may be an oxygen atom between the hydrocarbon group and each aromatic ring in formula (7-1), and when Z is a divalent group having an aromatic ring, there may be an oxygen atom between the divalent group having an aromatic ring and each aromatic ring in formula (7-1). The hydrogen atoms of the aromatic rings in formulas (7-1) and (7-2) may be substituted.

[0043] In the above formulas (5-1) to (5-4) and (6-2) to (6-5), B is preferably a divalent group represented by the following formula (8-1) or formula (8-2).

[0044] [ka]

[0045] In formulas (8-1) and (8-2), * represents a bond position, and in formula (8-1), Y is a bond, an oxygen atom, a carbonyl group, a sulfur atom, a sulfonyl group, a linear or branched divalent hydrocarbon group, or a divalent group having an aromatic ring. When Y is a hydrocarbon group, there may be an oxygen atom between the hydrocarbon group and each aromatic ring in formula (8-1), and when Y is a divalent group having an aromatic ring, there may be an oxygen atom between the divalent group having an aromatic ring and each aromatic ring in formula (8-1). The hydrogen atoms of the aromatic rings in formulas (8-1) and (8-2) may be substituted.

[0046] Methods for producing imide oligomers having the structure represented by formula (1-1) include, for example, reacting an acidic dianhydride represented by formula (9) with a diamine represented by formula (10). Alternatively, by using an aliphatic triamine or an aromatic triamine instead of the diamine represented by formula (10), imide oligomers having the structure represented by formula (2-1) can be produced.

[0047] [ka]

[0048] In formula (9), A is the same tetravalent group as A in formula (1-1) above.

[0049] [ka]

[0050] In formula (10), B is the same divalent group as B in formula (1-1) above, and R 1 ~R 4 Each of these is independently either a hydrogen atom or a monovalent hydrocarbon group.

[0051] A specific example of a method for reacting the acid dianhydride represented by formula (9) with the diamine represented by formula (10) is shown below. First, the diamine represented by formula (10) is dissolved in a solvent in which the amic acid oligomer obtained by the reaction is soluble (for example, N-methylpyrrolidone). The acid dianhydride represented by formula (9) is then added to the resulting solution and reacted to obtain an amic acid oligomer solution. Next, the solvent is removed by heating or reduced pressure, and the amic acid oligomer is further reacted by heating at approximately 200°C or higher for at least one hour. By adjusting the molar ratio of the acid dianhydride represented by formula (9) to the diamine represented by formula (10) and the imidation conditions, an imide oligomer having a desired number-average molecular weight and the structure represented by formula (1-1) at both ends can be obtained. Furthermore, by replacing a portion of the acid dianhydride represented by formula (9) with the acid anhydride represented by formula (11) below, an imide oligomer having a desired number-average molecular weight, having the structure represented by formula (1-1) above at one end, and the structure derived from the acid anhydride represented by formula (11) below at the other end can be obtained. In this case, the acid dianhydride represented by formula (9) and the acid anhydride represented by formula (11) below may be added simultaneously or separately. Furthermore, by replacing a portion of the diamine represented by formula (10) with the monoamine represented by formula (12) below, an imide oligomer having a desired number-average molecular weight, having the structure represented by formula (1-1) above at one end, and the structure derived from the monoamine represented by formula (12) below at the other end can be obtained. In this case, the diamine represented by formula (10) and the monoamine represented by formula (12) below may be added simultaneously or separately.

[0052] [ka]

[0053] In formula (11), Ar is an optionally substituted divalent aromatic group.

[0054] [ka]

[0055] In formula (12), Ar is an optionally substituted monovalent aromatic group, and R 5 and R 6 Each of these is independently either a hydrogen atom or a monovalent hydrocarbon group.

[0056] Methods for producing imide oligomers having the structure represented by formula (1-2) include, for example, a method of reacting an acid dianhydride represented by formula (9) with a phenolic hydroxyl group-containing monoamine represented by formula (13), or a method of reacting an acid dianhydride represented by formula (9) with a diamine represented by formula (10) with a phenolic hydroxyl group-containing monoamine represented by formula (13). Furthermore, by using an aliphatic triamine or an aromatic triamine instead of the diamine represented by formula (10), imide oligomers having the structure represented by formula (2-2) can be produced.

[0057] [ka]

[0058] In formula (13), Ar is an optionally substituted divalent aromatic group, and R 7 and R 8 Each of these is independently either a hydrogen atom or a monovalent hydrocarbon group.

[0059] A specific example of a method for reacting an acid dianhydride represented by formula (9) with a phenolic hydroxyl group-containing monoamine represented by formula (13) is shown below. First, the phenolic hydroxyl group-containing monoamine represented by formula (13) is dissolved in a solvent in which the amic acid oligomer obtained by the reaction is soluble (for example, N-methylpyrrolidone). The acid dianhydride represented by formula (9) is then added to the resulting solution and reacted to obtain an amic acid oligomer solution. Next, the solvent is removed by heating or reduced pressure, and the amic acid oligomer is further reacted by heating at approximately 200°C or higher for at least one hour. By adjusting the molar ratio of the acid dianhydride represented by formula (9) to the phenolic hydroxyl group-containing monoamine represented by formula (13) and the imidation conditions, an imide oligomer having a desired number-average molecular weight and the structure represented by formula (1-2) at both ends can be obtained. Furthermore, by replacing a portion of the phenolic hydroxyl group-containing monoamine represented by formula (13) with the monoamine represented by formula (12), an imide oligomer having a desired number-average molecular weight, having the structure represented by formula (1-2) at one end, and the structure derived from the monoamine represented by formula (12) at the other end can be obtained. In this case, the phenolic hydroxyl group-containing monoamine represented by formula (13) and the monoamine represented by formula (12) may be added simultaneously or separately.

[0060] A specific example of a method for reacting the acid dianhydride represented by formula (9) above with the diamine represented by formula (10) above with the phenolic hydroxyl group-containing monoamine represented by formula (13) above is shown below. First, the phenolic hydroxyl group-containing monoamine represented by formula (13) and the diamine represented by formula (10) are dissolved in a solvent in which the amic acid oligomer obtained by the reaction is soluble (for example, N-methylpyrrolidone). The acid dianhydride represented by formula (9) is then added to the resulting solution and reacted to obtain an amic acid oligomer solution. Next, the solvent is removed by heating or reduced pressure, and the amic acid oligomer is further reacted by heating at approximately 200°C or higher for at least one hour. By adjusting the molar ratio of the acid dianhydride represented by formula (9), the diamine represented by formula (10), and the phenolic hydroxyl group-containing monoamine represented by formula (13), and the imidation conditions, an imide oligomer having a desired number-average molecular weight and the structure represented by formula (1-2) at both ends can be obtained. Furthermore, by replacing a portion of the phenolic hydroxyl group-containing monoamine represented by formula (13) with the monoamine represented by formula (12), an imide oligomer having a desired number-average molecular weight, having the structure represented by formula (1-2) at one end, and the structure derived from the monoamine represented by formula (12) at the other end can be obtained. In this case, the phenolic hydroxyl group-containing monoamine represented by formula (13) and the monoamine represented by formula (12) may be added simultaneously or separately.

[0061] Examples of acid dianhydrides represented by formula (9) above include pyromellitic anhydride, 3,3'-oxydiphthalic anhydride, 3,4'-oxydiphthalic anhydride, 4,4'-oxydiphthalic anhydride, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, acid dianhydride of 4,4'-bis(2,3-dicarboxylphenoxy)diphenyl ether, p-phenylenebis(trimellitate anhydride), and 2,3,3',4'-biphenyltetracarboxylic dianhydride. In particular, as the acid dianhydride used as a raw material for the above-mentioned imide oligomer has superior solubility and heat resistance, aromatic acid dianhydrides with a melting point of 240°C or lower are preferred, aromatic acid dianhydrides with a melting point of 220°C or lower are more preferred, aromatic acid dianhydrides with a melting point of 200°C or lower are even more preferred, and 3,4'-oxydiphthalic acid dianhydride (melting point 180°C) and 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic acid anhydride (melting point 190°C) are especially preferred. In this specification, the term "melting point" refers to the value measured as the endothermic peak temperature when the temperature is increased at 10°C / min using a differential scanning calorimeter. Examples of differential scanning calorimeters include the EXTEAR DSC6100 (manufactured by SII Nanotechnology Co., Ltd.).

[0062] Among the diamines represented by the above formula (10), aromatic diamines include, for example, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, bis(4-(4-aminophenoxy)phenyl)methane, and 2,2-bis(4-(4-aminophenoxy)phenyl)methane. Examples include s(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(2-(4-aminophenyl)-2-propyl)benzene, 1,4-bis(2-(4-aminophenyl)-2-propyl)benzene, 3,3'-diamino-4,4'-dihydroxyphenylmethane, 4,4'-diamino-3,3'-dihydroxyphenylmethane, 3,3'-diamino-4,4'-dihydroxyphenyl ether, bisaminophenylfluorene, bistorydinfluorene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-diamino-3,3'-dihydroxyphenyl ether, 3,3'-diamino-4,4'-dihydroxybiphenyl, and 4,4'-diamino-2,2'-dihydroxybiphenyl.Among these, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 1,3-bis(2-(4-aminophenyl)-2-propyl)benzene, 1,4-bis(2-(4-aminophenyl)-2-propyl)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, and 1,4-bis(4-aminophenoxy)benzene are preferred due to their excellent availability, and 1,3-bis(2-(4-aminophenyl)-2-propyl)benzene, 1,4-bis(2-(4-aminophenyl)-2-propyl)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, and 1,4-bis(4-aminophenoxy)benzene are even more preferred due to their excellent solubility and heat resistance.

[0063] Examples of acid anhydrides represented by the above formula (11) include phthalic anhydride, 3-methylphthalic anhydride, 4-methylphthalic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, 1,8-naphthalic anhydride, 2,3-anthracene dicarboxylate anhydride, 4-tert-butylphthalic anhydride, 4-ethynylphthalic anhydride, 4-phenylethynylphthalic anhydride, 4-fluorophthalic anhydride, 4-chlorophthalic anhydride, 4-bromophthalic anhydride, and 3,4-dichlorophthalic anhydride.

[0064] Examples of monoamines represented by the above formula (12) include aniline, o-toluidine, m-toluidine, p-toluidine, 2,4-dimethylaniline, 3,4-dimethylaniline, 3,5-dimethylaniline, 2-tert-butylaniline, 3-tert-butylaniline, 4-tert-butylaniline, 1-naphthylamine, 2-naphthylamine, 1-aminoanthracene, 2-aminoanthracene, 9-aminoanthracene, 1-aminopyrene, 3-chloroaniline, o-anisidine, m-anisidine, p-anisidine, 1-amino-2-methylnaphthalene, 2,3-dimethylaniline, 2,4-dimethylaniline, 2,5-dimethylaniline, 3,4-dimethylaniline, 4-ethylaniline, 4-ethynylaniline, 4-isopropylaniline, 4-(methylthio)aniline, and N,N-dimethyl-1,4-phenylenediamine.

[0065] Examples of phenolic hydroxyl group-containing monoamines represented by the above formula (13) include 3-aminophenol, 4-aminophenol, 4-amino-o-cresol, 5-amino-o-cresol, 4-amino-2,3-xylenol, 4-amino-2,5-xylenol, 4-amino-2,6-xylenol, 4-amino-1-naphthol, 5-amino-2-naphthol, 6-amino-1-naphthol, and 4-amino-2,6-diphenylphenol. Among these, 4-amino-o-cresol and 5-amino-o-cresol are preferred because they have excellent availability and storage stability, and a high glass transition temperature can be obtained after curing.

[0066] When the above imide oligomer is produced by the manufacturing method described above, the imide oligomer is obtained as part of a mixture (imide oligomer composition) of multiple imide oligomers having the structure represented by formula (1-1) or multiple imide oligomers having the structure represented by formula (1-2) and each raw material. When an aliphatic triamine or aromatic triamine is used instead of the diamine represented by formula (10), the imide oligomer is obtained as part of a mixture (imide oligomer composition) of multiple imide oligomers having the structure represented by formula (2-1) or multiple imide oligomers having the structure represented by formula (2-2) and each raw material. Because the imidization rate of the imide oligomer composition is 70% or more, when used as a curing agent, it is possible to obtain a cured product that has superior mechanical strength at high temperatures and long-term heat resistance. The preferred lower limit for the imidation rate of the above imide oligomer composition is 75%, and the more preferred lower limit is 80%. There is no particular preferred upper limit for the imidation rate of the above imide oligomer composition, but the practical upper limit is 98%. The above "imidization rate" was measured using the total internal reflection (ATR) method with a Fourier transform infrared spectrophotometer (FT-IR), and the value derived from the carbonyl group of amic acid was 1660 cm⁻¹. -1 The peak absorbance area in the vicinity can be derived using the following formula. An example of the above Fourier transform infrared spectrophotometer is the UMA600 (manufactured by Agilent Technologies). In the following formula, "peak absorbance area of ​​amic acid oligomer" refers to the absorbance area of ​​the amic acid oligomer obtained by reacting an acidic dianhydride with a diamine or a phenolic hydroxyl group-containing monoamine, and then removing the solvent by evaporation or the like without performing an imidization step. Imidization rate (%) = 100 × (1 - (Peak absorbance area after imidization) / (Peak absorbance area of ​​amic acid oligomer))

[0067] From the viewpoint of solubility in a curable resin composition, it is preferable that the above imide oligomer composition dissolves in 3 g or more of tetrahydrofuran at 25°C.

[0068] The preferred lower limit for the content of the imide oligomer in the total 100 parts by weight of the curable resin and the curing agent (and the curing accelerator if described later) is 20 parts by weight, and the preferred upper limit is 80 parts by weight. Having the imide oligomer content within this range results in a curable resin composition with superior flexibility and processability before curing, and superior heat resistance after curing. A more preferred lower limit for the imide oligomer content is 25 parts by weight, and a more preferred upper limit is 75 parts by weight. Furthermore, if the imido oligomer according to the present invention is included in the above-described imido oligomer composition, the content of the above-described imido oligomer means the content of the imido oligomer composition (or, if other imido oligomers are used in combination, the total content of the imido oligomer composition and the other imido oligomers).

[0069] Preferably, the curable resin and curing agent described above do not contain compounds having a siloxane skeleton. By ensuring that the curable resin and curing agent do not contain compounds having a siloxane skeleton, it is possible to prevent contact failures and other problems caused by low molecular weight siloxane compounds derived from the curable resin composition.

[0070] The curable resin composition of the present invention contains a thermally conductive filler. By containing the above-mentioned thermally conductive filler, the curable resin composition of the present invention exhibits excellent thermal conductivity. In this specification, the term "thermally conductive filler" refers to a filler having a thermal conductivity of 10 W / m·K or higher.

[0071] From the viewpoint of thermal conductivity, the above-mentioned thermally conductive filler preferably includes at least one selected from the group consisting of alumina, aluminum nitride, silicon carbide, boron nitride, silicon nitride, magnesium oxide, zinc oxide, boron carbide, titanium carbide, zirconia, aluminum, and diamond.

[0072] Examples of the shapes of the thermally conductive filler include plate-like, spherical, irregular, crushed, and polygonal shapes. Furthermore, the thermally conductive filler may be aggregated particles formed by the aggregation of primary particles such as plate-like fillers.

[0073] The above-mentioned thermal conductive filler has a preferred lower limit of average particle size of 0.1 μm and a preferred upper limit of 300 μm. Having the average particle size of the thermal conductive filler within this range results in a curable resin composition with superior coatability and thermal conductivity. A more preferred lower limit of average particle size for the thermal conductive filler is 0.2 μm, and a more preferred upper limit is 200 μm. The average particle size of the above-mentioned thermal conductive filler can be measured by dispersing the thermal conductive filler in a solvent (water, organic solvent, etc.) using a particle size distribution analyzer such as the NICOMP 380ZLS (manufactured by PARTICLE SIZING SYSTEMS).

[0074] The preferred lower limit for the content of the above-mentioned thermal conductive filler in the curable resin composition of the present invention (excluding the solvent) is 50% by volume. A content of 50% by volume or more of the above-mentioned thermal conductive filler results in a curable resin composition with superior thermal conductivity. A more preferred lower limit for the content of the above-mentioned thermal conductive filler is 60% by volume. Furthermore, from the viewpoint of applicability and adhesion, the preferred upper limit for the content of the above-mentioned thermal conductive filler is 95% by volume, and the more preferred upper limit is 90% by volume.

[0075] The curable resin composition of the present invention may contain, in addition to the above-mentioned thermally conductive filler, other fillers having a thermal conductivity of less than 10 W / m·K, to the extent that they do not impede the objectives of the present invention.

[0076] Other fillers that can be used include inorganic fillers and organic fillers. Examples of the inorganic fillers mentioned above include silica, barium sulfate, glass powder, glass frit, glass fibers, and inorganic ion exchangers. Among these, silica and barium sulfate are preferred. Examples of the above-mentioned organic fillers include silicone rubber particles, acrylic rubber particles, urethane rubber particles, polyamide particles, polyamide-imide particles, polyimide particles, benzoguanamine particles, and core-shell particles thereof. Among these, polyamide particles, polyamide-imide particles, and polyimide particles are preferred. The above-mentioned other fillers may be used individually or in combination of two or more types.

[0077] The curable resin composition of the present invention preferably contains a dispersant. By containing the above-mentioned dispersant, the curable resin composition of the present invention can easily achieve a uniform dispersion state of the above-mentioned thermally conductive filler.

[0078] Examples of the above-mentioned dispersants include modified polyester compounds, modified polyether compounds, phosphate esters of modified polyether compounds, fatty acid derivatives, fatty acid polycarboxylic acid amine salts, cationic group-containing acrylic polymers, and polyurethane compounds. The above-mentioned dispersants may be used alone or in combination of two or more types.

[0079] The preferred lower limit of the dispersant content in 100 parts by weight of the curable resin composition of the present invention is 0.05 parts by weight, and the preferred upper limit is 4 parts by weight. Having the dispersant content within this range makes it easier to achieve a uniform dispersion state of the thermally conductive filler. A more preferred lower limit of the dispersant content is 0.1 parts by weight, and a more preferred upper limit is 3 parts by weight.

[0080] The curable resin composition of the present invention preferably contains a curing accelerator. By including the curing accelerator, the curing time can be shortened and productivity can be improved.

[0081] Examples of the curing accelerators mentioned above include imidazole-based curing accelerators, tertiary amine-based curing accelerators, phosphine-based curing accelerators, phosphorus-based curing accelerators, photobase generators, and sulfonium salt-based curing accelerators. Among these, imidazole-based curing accelerators are preferred due to their excellent storage stability. The curing accelerators may be used individually or in combination of two or more types.

[0082] The preferred lower limit for the content of the curing accelerator is 0.01 parts by weight and the preferred upper limit is 10 parts by weight, relative to 100 parts by weight of the total of the curable resin, curing agent, and curing accelerator. Having the curing accelerator content within this range provides superior effectiveness in shortening the curing time while maintaining excellent adhesion. A more preferred lower limit for the curing accelerator content is 0.05 parts by weight and a more preferred upper limit is 5 parts by weight.

[0083] The curable resin composition of the present invention may contain polymer components to the extent that they do not hinder the objectives of the present invention. The polymer components play a role as film-forming components, and by using the polymer components, the handling properties when the resulting curable resin composition is formed into a film can be improved.

[0084] The preferred lower limit for the number-average molecular weight of the above polymer component is 5,000, and the preferred upper limit is 100,000. Having the number-average molecular weight of the above polymer component within this range results in a curable resin composition with superior flexibility and processability before curing, and superior heat resistance after curing. A more preferred lower limit for the number-average molecular weight of the above polymer component is 8,000, and a more preferred upper limit is 80,000.

[0085] Examples of the polymer components mentioned above include polyimide, phenoxy resin, polyamide, polyamideimide, polymaleimide, cyanate resin, benzoxazine resin, acrylic resin, urethane resin, and polyester. Among these, phenoxy resin and polyimide are preferred from the viewpoint of heat resistance and handling properties, and polyimide is more preferred. The polymer components mentioned above may be used individually or in combination of two or more types.

[0086] The content of the polymer component described above is preferably 0.5 parts by weight and preferably 50 parts by weight per 100 parts by weight of the total of the curable resin, the curing agent (and the curing accelerator if one is included), and the polymer component. Having the polymer component content within this range results in a cured product of the resulting curable resin composition having superior heat resistance. A more preferable lower limit for the polymer component content is 1 part by weight and a more preferable upper limit is 40 parts by weight.

[0087] The above-mentioned curable resin composition may contain a solvent or reactive diluent from the viewpoint of coating properties and handling properties.

[0088] As for the solvents mentioned above, solvents with a boiling point of less than 200°C are preferred from the viewpoint of coating properties and storage stability. Examples of solvents with a boiling point below 200°C include alcohol-based solvents, ketone-based solvents, ester-based solvents, hydrocarbon-based solvents, halogen-based solvents, ether-based solvents, and nitrogen-containing solvents. Examples of the alcohol-based solvents mentioned above include methanol, ethanol, isopropyl alcohol, n-propyl alcohol, isobutyl alcohol, n-butyl alcohol, tertiary butyl alcohol, and 2-ethylhexanol. Examples of the ketone-based solvents mentioned above include acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, and diacetone alcohol. Examples of the ester-based solvents mentioned above include methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, methoxybutyl acetate, amyl acetate, n-propyl acetate, isopropyl acetate, methyl lactate, ethyl lactate, and butyl lactate. Examples of the hydrocarbon solvents mentioned above include benzene, toluene, xylene, n-hexane, isohexane, cyclohexane, methylcyclohexane, ethylcyclohexane, isooctane, n-decane, and n-heptane. Examples of the halogenated solvents mentioned above include dichloromethane, chloroform, and trichloroethylene. Examples of the ether-based solvents mentioned above include diethyl ether, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, diisopropyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, 3-methoxy-3-methyl-1-butanol, ethylene glycol monotertiary butyl ether, propylene glycol monomethyl ether propionate, 3-methoxybutanol, diethylene glycol dimethyl ether, anisole, and 4-methylanisole. Examples of nitrogen-containing solvents include acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone. In particular, from the viewpoint of handling ease and solubility of imide oligomers, at least one selected from the group consisting of ketone solvents with a boiling point of 60°C or higher and less than 200°C, ester solvents with a boiling point of 60°C or higher and less than 200°C, and ether solvents with a boiling point of 60°C or higher and less than 200°C is preferred. Examples of such solvents include methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, isobutyl acetate, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, cyclohexanone, methylcyclohexanone, diethylene glycol dimethyl ether, and anisole. The above "boiling point" refers to the value measured under conditions of 101 kPa, or the value converted to 101 kPa using a boiling point conversion chart or similar.

[0089] The reactive diluent described above is preferably a reactive diluent having one or more reactive functional groups in one molecule. Examples of reactive diluents having one or more reactive functional groups in a single molecule include monofunctional epoxy resins. Examples of the monofunctional epoxy resins mentioned above include monoglycidyl compounds and monoalicyclic epoxy compounds. Examples of the above monoglycidyl compounds include tert-butylphenylglycidyl ether, 2-ethylhexylglycidyl ether, allylglycidyl ether, phenylglycidyl ether, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 1-(3-glycidoxypropyl)1,1,3,3,3-pentamethyldisiloxane, and N-glycidyl-N,N-bis[3-(trimethoxysilyl)propyl]amine. Examples of the above-mentioned mono-alicyclic epoxy compounds include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. These reactive diluents may be used individually or in combination of two or more.

[0090] The preferred lower limit for the content of the solvent or reactive diluent in 100 parts by weight of the curable resin composition of the present invention is 0.5 parts by weight, and the preferred upper limit is 30 parts by weight. Having the solvent content within this range results in a curable resin composition with superior coating properties. A more preferred lower limit for the content of the solvent or reactive diluent is 1 part by weight, and a more preferred upper limit is 20 parts by weight.

[0091] The curable resin composition of the present invention may further contain additives such as coupling agents, storage stabilizers, bleed inhibitors, fluxes, and leveling agents, to the extent that they do not hinder the objectives of the present invention.

[0092] The curable resin composition of the present invention preferably does not contain compounds having an amide skeleton. If such compounds are included, the hydrogen bonding of the amide groups may increase the viscosity of the curable resin composition, making it difficult to fill with a high concentration of thermally conductive filler and potentially resulting in low thermal conductivity. In addition, water absorption may increase, and the adhesive strength after moisture absorption may decrease.

[0093] Methods for producing the curable resin composition of the present invention include, for example, a method in which a curable resin, a curing agent, and polymer components are mixed using a mixer, and then a thermally conductive filler and a dispersant are further mixed. Examples of such mixers include homodispers, universal mixers, Banbury mixers, and kneaders.

[0094] The curable resin composition of the present invention has a preferred lower viscosity of 10 mPa·s and a preferred upper viscosity of 600 mPa·s at 25°C. Having a viscosity within this range at 25°C results in excellent coatability of the curable resin composition of the present invention. A more preferred lower viscosity at 25°C is 20 mPa·s, and a more preferred upper viscosity is 500 mPa·s. In this specification, "viscosity" refers to the value measured using an E-type viscometer at a speed of 10 rpm. Examples of E-type viscometers include the TPE-100 (manufactured by Toki Sangyo Co., Ltd.).

[0095] The curable resin composition of the present invention has a preferred lower limit of 4 MPa for the shear adhesion strength of the cured product to aluminum. A shear adhesion strength of 4 MPa or higher for the cured product to aluminum makes the curable resin composition of the present invention suitable for use as a thermally conductive adhesive. A more preferred lower limit for the shear adhesion strength of the cured product to aluminum is 5 MPa. Furthermore, while there is no particular preferred upper limit for the shear adhesion strength of the cured product to aluminum, the practical upper limit is 20 MPa. The shear adhesion strength of the cured material to the aluminum can be measured by using a Tensilon universal material tester (A&D Co., Ltd., "RTC-1350A") in accordance with JIS K 6850, pulling the test specimen at a tensile speed of 1 mm / min at 25°C, and calculating the stress at which peeling occurs. The test specimen is prepared by applying the curable resin composition to a thickness of approximately 100 μm after drying, drying to remove the solvent, then bonding a 25 mm thick aluminum substrate to both sides of the curable resin composition with a bonding width of 12.5 mm, and heating at 190°C for 1 hour. For example, A-1050P can be used as the aluminum substrate.

[0096] The curable resin composition of the present invention has a preferred lower limit of 350°C for the 1% weight loss temperature after curing. Because the temperature at which the 1% weight loss occurs after curing is 350°C or higher, the curable resin composition of the present invention can be suitably used in thermally conductive adhesives (heat-dissipating adhesives) that require particularly high heat resistance. The 1% weight loss temperature mentioned above can be determined by performing thermogravimetric measurements using a thermogravimetric analyzer under heating conditions from 30°C to 500°C at a heating rate of 10°C / min. Examples of such thermogravimetric analyzers include the TG / DTA6200 (manufactured by Hitachi High-Tech Science Corporation). The cured material used to measure the 1% weight loss temperature is prepared by coating a curable resin composition onto a PET film substrate to a thickness of 100 μm after drying, drying it, and then curing it by heating it at 190°C for 1 hour.

[0097] The cured product of the curable resin composition of the present invention is also one of the present inventions. An adhesive made using the curable resin composition of the present invention is also one of the present inventions. An adhesive film can be obtained by coating the adhesive of the present invention onto a base film and then drying it. An adhesive film made using the adhesive of the present invention is also one of the present inventions. The adhesive of the present invention can be suitably used as a thermally conductive adhesive (heat-dissipating adhesive), and the adhesive film of the present invention can be suitably used as a thermally conductive adhesive film (heat-dissipating adhesive film). [Effects of the Invention]

[0098] According to the present invention, it is possible to provide a curable resin composition that is excellent in heat resistance, thermal conductivity, and adhesion. Furthermore, according to the present invention, it is possible to provide a cured product of the curable resin composition, as well as an adhesive and adhesive film made using the curable resin composition. [Modes for carrying out the invention]

[0099] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0100] (Synthesis Example 1 (Preparation of Imido Oligomer Composition A)) 17.2 parts by weight of 1,4-bis(2-(4-aminophenyl)-2-propyl)benzene (Mitsui Chemicals Fine, "Bisaniline P") was dissolved in 200 parts by weight of N-methylpyrrolidone (Tokyo Chemical Industries, Ltd.). 52.0 parts by weight of 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic anhydride (Tokyo Chemical Industries, Ltd.) was added to the resulting solution, and the mixture was stirred at 25°C for 2 hours to obtain an amic acid oligomer solution. After removing N-methylpyrrolidone from the obtained amic acid oligomer solution under reduced pressure, the mixture was heated at 300°C for 2 hours to obtain imide oligomer composition A (imidization rate 97%). Regarding the obtained imide oligomer composition A, 1 1H-NMR, GPC, and FT-IR analyses were performed. As a result, it was confirmed that imide oligomer composition A contains an imide oligomer having the structure represented by formula (5-1) or (5-3) above (A is a 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic anhydride residue, and B is a 1,4-bis(2-(4-aminophenyl)-2-propyl)benzene residue). Furthermore, the number-average molecular weight of imide oligomer composition A was 1500.

[0101] (Synthesis Example 2 (Preparation of Imide Oligomer Composition B)) 104 parts by weight of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 300 parts by weight of N-methylpyrrolidone (manufactured by Fujifilm Wako Pure Chemical Corporation, "NMP"). A solution obtained by diluting 28 parts by weight of priamine 1074 (manufactured by Croda), which is a dimer diamine, with 100 parts by weight of N-methylpyrrolidone was added to the resulting solution, and the mixture was stirred at 25°C for 2 hours to react to obtain an amic acid oligomer solution. After removing N-methylpyrrolidone from the obtained amic acid oligomer solution under reduced pressure, heating at 300°C for 2 hours gave imide oligomer composition B (imidization rate: 93%). Regarding the obtained imide oligomer composition B, 1 1H-NMR, GPC, and FT-IR analyses were performed. As a result, it was confirmed that imide oligomer composition B contains an imide oligomer having a structure represented by the above formula (5-1) or (5-3) (A is a 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride residue, B is a dimer diamine residue). Further, the number average molecular weight of the imide oligomer composition B was 2200.

[0102] (Synthesis Example 3 (Preparation of Imide Oligomer Composition C)) 21.8 parts by weight of 3-aminophenol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 200 parts by weight of N-methylpyrrolidone (manufactured by Tokyo Chemical Industry Co., Ltd.). 17.2 parts by weight of 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the resulting solution, and the mixture was stirred at 25°C for 2 hours to react to obtain an amic acid oligomer solution. After removing N-methylpyrrolidone from the obtained amic acid oligomer solution under reduced pressure, heating at 300°C for 2 hours gave imide oligomer composition C (imidization rate: 96%). Regarding the obtained imide oligomer composition C, 11H-NMR, GPC, and FT-IR analyses were performed. As a result, it was confirmed that imide oligomer composition C contains an imide oligomer having the structure represented by formula (6-1) above (A is a 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic acid anhydride residue, and R is a hydrogen atom). Furthermore, the number-average molecular weight of imide oligomer composition C was 700.

[0103] (Synthesis Example 4 (Preparation of Cyclohexanone Solution of Polyimide Resin)) In a reaction vessel equipped with a stirrer, a water divider, and a nitrogen gas inlet tube, 54.6 parts by weight of 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 150 parts by weight of cyclohexanone were charged and dissolved. To the resulting solution, a mixed solution of 56.1 parts by weight of the dimeramine Priamine 1074 (manufactured by Croda) and 55.0 parts by weight of cyclohexanone was added dropwise, and an imidation reaction was carried out at 150°C for 8 hours to obtain a polyimide resin solution. The solid content concentration of the obtained polyimide resin solution was 45% by weight, and the number-average molecular weight of the polyimide resin was 27,000.

[0104] (Examples 1-10, Comparative Examples 1-3) Formulas 1 to 7 were prepared by stirring and mixing each material according to the mixing ratios listed in Table 1. Then, each formula and each material were stirred and mixed according to the mixing ratios listed in Table 2 to prepare the curable resin compositions for Examples 1 to 10 and Comparative Examples 1 to 3. Each of the obtained curable resin compositions was coated onto a PET substrate film to a thickness of 100 μm after drying, and dried at 100°C for 10 minutes to obtain a curable resin composition film.

[0105] (Thermal conductivity after curing) Cured products were obtained by heating the curable resin composition films obtained in the examples and comparative examples at 190°C for 1 hour. The thermal conductivity of the obtained cured products was measured at 23°C using a T3Ster DynTIM Tester (Mentor, a Siemens Business). The results are shown in Table 2.

[0106] <Rating> The following evaluations were performed on each curable resin composition obtained in the examples and comparative examples. The results are shown in Table 2.

[0107] (Handling properties of the film before curing) The curable resin composition films obtained in the examples and comparative examples (after drying, before heat curing) were wrapped around a 5 mm diameter cylinder at 25°C to check for cracking or chipping of the thermosetting adhesive film. Handling was evaluated using the following criteria: "○" for no cracks or chips, "△" for partial cracks or chips, and "×" for cracks or chips covering the entire film.

[0108] (Shear adhesion strength of the cured material to aluminum) Test specimens were prepared by bonding 25 mm thick aluminum substrates "A-1050P" to both sides of the curable resin composition films obtained in the examples and comparative examples, such that the width of the bonded portion was 12.5 mm, and then heating at 190°C for 1 hour. The resulting test specimens were measured in accordance with JIS K6850 using a Tensilon universal material tester (A&D Co., Ltd., "RTC-1350A") at 25°C and a tensile speed of 1 mm / min to the cured material (immediately after curing). Furthermore, the obtained test specimens were stored at 120°C and 85%RH for 192 hours, and then the shear adhesion strength of the cured material to aluminum (after storage at 120°C, 85%RH, and 192 hours) was measured under the same conditions as described above.

[0109] (Heat resistance: 1% weight loss temperature) Each curable resin composition obtained in the examples and comparative examples was coated onto a PET substrate film to a thickness of 100 μm after drying, dried, and then cured by heating at 190°C for 1 hour to produce a cured product. The obtained cured product was measured using a thermogravimetric analyzer (Hitachi High-Tech Science Corporation, "TG / DTA6200") in a temperature range of 30°C to 500°C under heating conditions of 10°C / min to determine the 1% weight loss temperature.

[0110] [Table 1]

[0111] [Table 2] [Industrial applicability]

[0112] According to the present invention, it is possible to provide a curable resin composition that is excellent in heat resistance, thermal conductivity, and adhesion. Furthermore, according to the present invention, it is possible to provide a cured product of the curable resin composition, as well as an adhesive and adhesive film made using the curable resin composition.

Claims

1. A curable resin composition comprising a curable resin, a curing agent, a thermally conductive filler, and a curing accelerator, The curing agent comprises an imide oligomer, The imide oligomer has a reactive functional group that can react with the curable resin, The curable resin and the curing agent do not contain compounds having a siloxane skeleton. The curable resin comprises at least one selected from the group consisting of epoxy resin, cyanate resin, maleimide resin, and benzoxazine resin. The thermal conductivity of the curable resin composition after curing is 1 W / m·K or higher. A curable resin composition characterized by the following features.

2. The curable resin composition according to claim 1, wherein the molecular weight of the imide oligomer is 5000 or less.

3. The curable resin composition according to claim 1 or 2, wherein the reactive functional group is at least one selected from the group consisting of an acid anhydride group, a phenolic hydroxyl group, and an amino group.

4. The curable resin composition according to claim 1 or 2, wherein the thermally conductive filler comprises at least one selected from the group consisting of alumina, aluminum nitride, silicon carbide, boron nitride, silicon nitride, magnesium oxide, zinc oxide, boron carbide, titanium carbide, zirconia, aluminum, and diamond.

5. The curable resin composition according to claim 1 or 2, wherein the content of the thermally conductive filler in the curable resin composition (excluding the solvent) is 50% by volume or more.

6. The above curable resin composition further contains polymer components, The polymer component has a number average molecular weight of 5000 or more. The curable resin composition according to claim 1 or 2, wherein the polymer component comprises at least one selected from the group consisting of phenoxy resins and polyimides.

7. A curable resin composition according to claim 1 or 2, which does not contain a compound having an amide skeleton.

8. The curable resin composition according to claim 1 or 2, wherein the shear adhesion strength of the cured product to aluminum is 4 MPa or more.

9. The curable resin composition according to claim 1 or 2, wherein the temperature at which the 1% weight loss after curing is 350°C or higher.

10. A cured product of the curable resin composition according to claim 1 or 2.

11. An adhesive comprising the curable resin composition according to claim 1 or 2.

12. An adhesive film made using a cured product of the curable resin composition according to claim 1 or 2, or an adhesive made using the curable resin composition according to claim 1 or 2.

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