Aromatic amine compound, curing agent and epoxy resin composition

Abstract

To provide an aromatic amine compound capable of improving the balance between good mechanical strength and light weight.SOLUTION: There is provided an aromatic amine compound represented by the following formula (1). (wherein, R1 and R2 each independently are a hydrogen atom, an amino group or an organic group and at least one of them is an amino group or an organic group having an amino group and R3 and R4 each independently represent a hydrocarbon group having 4 to 16 carbon atoms.)SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an aromatic amine compound, a curing agent, and an epoxy resin composition. More specifically, the present invention relates to an aromatic amine compound, a curing agent using the aromatic amine compound, an epoxy resin composition containing the aromatic amine compound as a curing agent, a molded article including a cured product of the epoxy resin composition, and a transportation equipment molded article including a cured product of the epoxy resin composition.

Background Art

[0002] Conventionally, amines, acid anhydrides, polyamides, imidazoles, mercaptans, phenols, etc. are known as curing agents for epoxy resins. Since the performance of the cured product varies greatly depending on the type of curing agent, research and development of curing agents are promoted according to the applications of the epoxy resin composition.

[0003] For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2011-195580) discloses a diamine compound having a fluorene skeleton, in which a substituent having an amino group is bonded to the carbon atoms at the 2-position and 7-position in the skeleton, and no substituent is bonded to the carbon atom at the 9-position in the skeleton, in order to obtain characteristics derived from the high planarity of the fluorene skeleton. Further, it is disclosed that the diamine compound can be used as a raw material or a crosslinking agent for polyamides, polyimides, polyurethanes, epoxy resins, etc.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, from the perspective of energy efficiency, weight reduction by replacing metal parts of transportation machinery and the like has been actively carried out. The cured product of thermosetting resins such as epoxy resin is lighter than metal and has excellent heat resistance and the like, so it has attracted attention as a metal replacement part. However, according to the study by the present inventor, when a diamine compound as disclosed in Patent Document 1 is used as a curing agent, although weight reduction can be achieved to some extent by the fluorene skeleton, it has been found that it is not sufficient in terms of achieving both weight reduction and good mechanical strength.

[0006] Therefore, from the viewpoint of improving the balance between weight reduction and elastic modulus, the present inventor focused on the development of a new amine compound and conducted intensive studies. As a result, a new amine compound was completed by bonding a substituent having an amino group to at least one of the 2-position or 7-position carbon atoms in the fluorene skeleton and bonding a bulky substituent to the 9-position carbon atom in the fluorene skeleton. That is, in such an amine compound, it was found that the mechanical properties of the cured product can be improved by crosslinking of the amino group, and weight reduction can be effectively achieved by the fluorene skeleton and the bulky substituent.

Means for Solving the Problems

[0007] According to the present invention, technologies related to the following aromatic amine compound, curing agent, and epoxy resin composition are provided.

[0008] [1] An aromatic amine compound represented by the following formula (1).

Chemical formula

[10] The epoxy resin composition according to [9], wherein the ratio of the epoxy equivalent in the epoxy resin to the active hydrogen equivalent in the curing agent (epoxy / active hydrogen) is 0.8 or more and 1.5 or less, and the epoxy resin composition.

[11] A molded article including a cured product of the epoxy resin composition according to [9] or

[10] .

[12] A transport equipment molded article including a cured product of the epoxy resin composition according to any one of [9] to

[11] .

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a technology related to an aromatic amine compound, a curing agent, and an epoxy resin composition that can improve the balance between good mechanical strength and weight reduction.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0012] In this specification, the notation "a~b" in the description of a numerical range represents a to b, unless otherwise specified. For example, "1~5 mass%" means "1 mass% or more and 5 mass% or less".

[0013] <Aromatic Amine Compound> The aromatic amine compound of this embodiment is represented by the following formula (1) (hereinafter, it will be described by referring to it as "aromatic amine compound (A)").

[0014]

Chemical Formula

[0015] The aromatic amine compound (A) has a structural unit represented by the formula (1), thereby realizing weight reduction of the cured product while obtaining good strength at a high level. Although the details of such reasons are not clear, it is considered that a plurality of aromatic groups due to the fluorene skeleton provide rigidity and mechanical strength, and the bulky substituent bonded to the 9-position carbon atom in the fluorene skeleton makes it bulky, resulting in low specific gravity. Furthermore, since the bulky substituent is a saturated hydrocarbon group with a relatively large number of carbon atoms, it is presumed that toughness is obtained and the specific elastic modulus is easily improved while maintaining low specific gravity. In addition, since the amino group has two crosslinking points, it can be crosslinked more densely than the single crosslinking point of the hydroxyl group of the phenolic curing agent, so it is considered that the specific elastic modulus of the cured product can be increased while maintaining low specific gravity.

[0016] In formula (1), R1 and R2 are each independently hydrogen, an amino group or an organic group, and at least one of them is an amino group or an organic group having an amino group. The organic group may be a group containing carbon, and examples thereof include an aliphatic group that may have a substituent having 1 to 20 carbon atoms and an aromatic group that may have a substituent. Among them, from the viewpoint of obtaining good flexural strength, it is preferably an aromatic group having at least an amino group. Also, the organic group preferably does not contain a hetero element inside. Specifically, it preferably does not contain an oxygen atom with an ether bond or an ester bond. Also, as the organic group having an amino group, for example, an aliphatic group having 1 to 6 carbon atoms having an amino group or a divalent aromatic group having an amino group is preferable.

[0017] The amino group includes a primary amino group and a secondary amino group, and a primary amino group is preferable.

[0018] Also, it is preferable that both R1 and R2 have an amino group. This increases the number of crosslinking points and easily improves the mechanical strength.

[0019] In the formula (1), R3 and R4 are each independently a hydrocarbon group having 4 to 16 carbon atoms, which may be either saturated or unsaturated. From the viewpoint of obtaining stability, it is preferably a saturated hydrocarbon group having 4 to 16 carbon atoms. Moreover, the number of carbon atoms is preferably 6 to 12, more preferably 6 to 10. By setting the number of carbon atoms to 4 or more, toughness can be obtained and light weight can be easily achieved. On the other hand, by setting the number of carbon atoms to 16 or less, the compound can be stabilized and the reactivity can be easily maintained well.

[0020] R3 and R4 are each independently, and the hydrocarbon group may be either chain or cyclic, preferably a linear or branched hydrocarbon group, or one in which a cyclic hydrocarbon group is bonded to one of the divalent chain hydrocarbon groups. Specifically, the hydrocarbon group of R3 and R4 may be a linear hydrocarbon group having 6 to 12 carbon atoms, or may contain an adamantyl group.

[0021] Specifically, the aromatic diamine compounds represented by the following formulas (A1) to (A6) can be mentioned.

[0022]

Chemical formula

[0023]

Chemical formula

[0024]

Chemical formula

[0025]

Chemical formula

[0026]

Chemical formula

[0027] [Chemical formula]

[0028] [Manufacturing method] Next, an example of a method for producing the aromatic amine compound (A) will be described. The reaction is preferably carried out under an inert gas atmosphere.

[0029] The aromatic amine compound (A) is obtained by reacting fluorene compounds with an amine compound in the presence of a basic catalyst. Specifically, for example, the following two procedures (i) to (ii) can be mentioned.

[0030] (i) First, prepare a hydrocarbon-substituted fluorene in which a hydrocarbon group having 4 to 16 carbon atoms is introduced at the 9-position of the fluorene skeleton. As the hydrocarbon-substituted fluorene, a commercially available product may be used, or it may be synthesized by a known method. For example, after substituting the hydroxyl group of adamantane ethanol with a halogen, an adamantyl group may be introduced at the 9-position of the fluorene skeleton by a halogen atom. Next, in the presence of a basic catalyst, react the hydrocarbon-substituted fluorene with an amine compound to introduce an amino group into at least one of the 2-position and 7-position of the fluorene skeleton, thereby obtaining the aromatic amine compound (A). The reaction conditions are appropriately set, but may be 80 to 110 °C and 4 to 36 hours.

[0031] (ii) First, prepare an aminofluorene in which an amino group is bonded to at least one of the 2-position and 7-position of the fluorene skeleton. As the aminofluorene, a commercially available product may be used, or it may be synthesized by a known method. Subsequently, protect the amino group of the aminofluorene with an inert group. This prevents the amino group from being substituted by a hydrocarbon group during the subsequent introduction of the hydrocarbon group. Next, add a basic catalyst and introduce a hydrocarbon group having 4 to 16 carbon atoms at the 9-position of the fluorene skeleton of the aminofluorene. The reaction conditions are appropriately set, but may be 80 to 180 °C and 4 to 36 hours. The introduction of the hydrocarbon group can be carried out in the same manner as the method described in (i) above. Subsequently, by removing the inert group bonded to the amino group, an aromatic amine compound (A) is obtained. Examples of the above-mentioned inert groups include tert-butoxycarbonyl (Boc) group, acetyl (Ac), benzoyl (Bz), pivaloyl (Piv) group, allyloxycarbonyl (Alloc) group, benzyloxycarbonyl (Cbz) group, and 2-(trimethylsilyl)ethoxycarbonyl (Teoc) group. The removal of the inert group is appropriately set according to its type. For example, when the tert-butoxycarbonyl (Boc) group is used, it can be removed under acidic conditions such as trifluoroacetic acid.

[0032] Examples of the basic catalyst used in the above methods (i) and (ii) include hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide, and calcium hydroxide; carbonates such as sodium carbonate, calcium carbonate, and potassium carbonate; oxides such as lime; sulfites such as sodium sulfite; phosphates such as sodium phosphate; and amines such as ammonia, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, hexamethylenetetramine, and pyridine.

[0033] Also, a palladium catalyst may be used as the catalyst for promoting the coupling reaction. Examples of the palladium catalyst include tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) and palladium carbon. When a mixed solvent of water and an organic solvent is used, a phase transfer catalyst may be used for the purpose of promoting the reaction between two phases. Examples of the phase transfer catalyst include tetrabutylammonium chloride and tetrabutylammonium bromide.

[0034] Water is generally used as the reaction solvent, but an organic solvent may also be used. Examples of the organic solvent include alcohols, ethers, ketones, aromatics, dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF). Specific examples of alcohols include methanol, ethanol, propyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, etc. Specific examples of ethers include cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, 4-methyltetrahydropyran, etc. Specific examples of ketones include acetone, methyl ethyl ketone, etc. Specific examples of aromatics include toluene, xylene, etc. These may be used alone or in combination of two or more. Among them, it is preferably a mixed solvent of water and alcohols and ethers.

[0035] Fluorenes and the amine compound are preferably used so that the molar ratio (fluorenes / amine compound) is 1 to 3. Also, the basic catalyst is preferably prepared so that the molar ratio (basic catalyst / fluorenes) is 3 to 5 with respect to fluorenes.

[0036] The synthesis of the aromatic amine compound (A) can be confirmed by thin layer chromatography and 1 1H-NMR measurement.

[0037] [Use] The aromatic amine compound (A) can be used for the same uses as conventional aromatic amine compounds, such as raw materials, curing agents, crosslinking agents, etc. of polycondensation polymers such as polyamide, polyimide, epoxy resin, polyurethane, and thermosetting polymers. Among them, from the viewpoint of improving the balance between weight reduction and mechanical strength of the cured product, the aromatic amine compound (A) is preferably used as a curing agent for epoxy resin.

[0038] <Epoxy resin composition> The epoxy resin composition of the present embodiment (hereinafter also simply referred to as "resin composition") contains an epoxy resin and a curing agent using the above-mentioned aromatic amine compound (A). By using the aromatic amine compound (A) as a curing agent, the epoxy resin composition can improve the compatibility between weight reduction and mechanical strength of the cured product of the epoxy resin composition.

[0039] [Specific gravity] The specific gravity of the cured product (25 °C) of the resin composition of the present embodiment is preferably 1.30 or less, more preferably 1.25 or less, still more preferably 1.20 or less, and even more preferably 1.18 or less. On the other hand, the specific gravity of the cured product (25 °C) of the resin composition of the present embodiment is preferably 1.0 or more. By setting the specific gravity of the cured product of the resin composition to be equal to or higher than the above lower limit value, good strength can be obtained, and heat resistance and dimensional stability can be maintained. On the other hand, by setting the specific gravity of the cured product of the resin composition to be equal to or lower than the above upper limit value, weight reduction can be achieved.

[0040] Hereinafter, the details of each component contained in the resin composition of the present embodiment will be described.

[0041] [Epoxy resin] As the epoxy resin, monomers, oligomers, and polymers having two or more epoxy groups in one molecule can be used, and their molecular weights and molecular structures are not particularly limited.

[0042] Examples of epoxy resins include bisphenol-type epoxy resins (such as bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, bisphenol S-type epoxy resin, water-added bisphenol A-type epoxy resin, dimer acid-modified bisphenol-type epoxy resin, etc.), novolac-type epoxy resins (such as phenol novolac-type epoxy resin, cresol novolac-type epoxy resin, biphenyl-type epoxy resin, etc.), naphthalene-type epoxy resin, fluorene-type epoxy resin (such as bisarylfluorene-type epoxy resin, etc.), aromatic epoxy resins such as triphenylmethane-type epoxy resin (such as tris(hydroxyphenyl)methane-type epoxy resin, etc.), nitrogen-containing ring epoxy resins such as triepoxypropyl isocyanurate (triglycidyl isocyanurate), hydantoin epoxy resin, etc., and aliphatic epoxy resins, alicyclic epoxy resins (such as dicyclo-ring-type epoxy resin, etc.), glycidyl ether-type epoxy resin, glycidyl amine-type epoxy resin, etc. As the epoxy resin, one of these may be used alone, or two or more different types may be used in combination. Among them, from the viewpoint of effectively achieving weight reduction while maintaining mechanical strength by having a rigid structure, glycidyl amine-type epoxy resin, bisphenol-type epoxy resin, phenyl-type epoxy resin, naphthalene-type epoxy resin, and fluorene-type epoxy resin are preferable, and glycidyl amine-type epoxy resin is more preferable.

[0043] Also, glycidylamine type epoxy resins are, for example, epoxy resins having a structure in which the amino groups of amines are glycidylated. Examples include tetraglycidyldiaminodiphenylmethane, glycidyl compounds of xylenediamine, triglycidylaminophenol (triglycidyl - p - aminophenol, triglycidyl - m - aminophenol, etc.), tetraglycidyldiaminodiphenylmethane, tetraglycidyldiaminodiphenylsulfone, tetraglycidyldiaminodiphenylether, tetraglycidylbisaminomethylcyclohexanone, diglycidyltoluidine, diglycidylaniline, diglycidylmethoxyaniline, diglycidyldimethylaniline, diglycidyltrifluoromethylaniline, and the like.

[0044] The content of the epoxy resin is preferably 10% by mass or more and 70% by mass or less, more preferably 25% by mass or more and 60% by mass or less, and even more preferably 35% by mass or more and 55% by mass or less, based on the total amount of the resin composition. By setting the content of the epoxy resin to be at least the above lower limit value, the fluidity and moldability of the resin composition can be more effectively improved. On the other hand, by setting the content of the epoxy resin to be at most the above upper limit value, the curability can be improved and a good cured product can be obtained.

[0045] [Curing agent] The curing agent contains at least the above - mentioned aromatic amine compound (A). The aromatic amine compound (A) functions as a poly - addition type curing agent.

[0046] The ratio of the epoxy equivalent in the epoxy resin to the active hydrogen equivalent in the curing agent (epoxy / active hydrogen) is preferably 0.8 or more and 1.5 or less, and more preferably 1.1 or more and 1.3 or less. By setting the ratio (epoxy / active hydrogen) to be at least the above lower limit value, the cross - linking of the amine groups of the aromatic amine compound (A) can be promoted, the curability can be improved, and weight reduction and mechanical strength can be improved. On the other hand, by setting the ratio (epoxy / active hydrogen) to be at most the above upper limit value, good fluidity and moldability of the resin composition can be maintained.

[0047] The content of the curing agent is appropriately set according to the epoxy resin, but it is preferably 20% by mass or more and 70% by mass or less, more preferably 30% by mass or more and 65% by mass or less, and still more preferably 40% by mass or more and 60% by mass or less with respect to the total amount of the resin composition. By setting the content of the curing agent to be not less than the above lower limit value, the curability can be improved and a good cured product can be obtained. On the other hand, by setting the content of the curing agent to be not more than the above upper limit value, the fluidity and moldability of the resin composition can be more effectively improved.

[0048] [Curing accelerator] The resin composition of this embodiment may contain a curing accelerator. The curing accelerator typically promotes the reaction between the epoxy resin and the curing agent.

[0049] Specific examples of the curing accelerator include phenolic compounds such as phenol, bisphenol A, nonylphenol, and 2,3-dihydroxynaphthalene.

[0050] When using a curing accelerator, the content of the curing accelerator is appropriately set according to the application, but it is preferably 0.1 to 5% by mass, more preferably 0.2 to 3% by mass with respect to the total amount of the resin composition. By setting the content of the curing accelerator to be not less than the above lower limit value, the resin composition can be appropriately cured more easily. On the other hand, by setting the content of the curing accelerator to be not more than the above upper limit value, the molten state can be lengthened and a lower viscosity state can be maintained for a longer time.

[0051] On the other hand, since the resin composition of this embodiment uses an aromatic amine compound (A) as the curing agent, good curability can be obtained even without containing a curing accelerator.

[0052] [Filler] The filler is used to enhance the mechanical strength, impart heat resistance, flame retardancy, etc. according to the application of the cured product.

[0053] As the filler, inorganic particles and / or organic particles are used. Specific examples of the inorganic particles include silicates such as talc, calcined clay, uncalcined clay, mica, and glass; oxides such as fused silica, spherical silica, crushed silica, titanium oxide, and boehmite; carbonates such as calcium carbonate, magnesium carbonate, and hydrotalcite; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; sulfates or sulfites such as barium sulfate, calcium sulfate, and calcium sulfite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; nitrides such as aluminum nitride, boron nitride, silicon nitride, and carbon nitride; titanates such as strontium titanate and barium titanate; reinforcing fibers such as glass fiber, carbon fiber, and metal fiber. These may be used alone or in combination of two or more.

[0054] The content of the filler is appropriately set according to the application, but it is preferably 1 to 45% by mass, more preferably 10 to 40% by mass, and even more preferably 20 to 35% by mass based on the total amount of the resin composition. By setting the content of the filler to be not less than the above lower limit value, the storage stability and curability of the cured product can be improved. Also, by setting the content of the filler to be not more than the above upper limit value, good fluidity of the resin composition can be obtained, and the moldability can be effectively improved.

[0055] [Coupling Agent] When the resin composition of the present embodiment contains inorganic particles as a filler, etc., it may contain a coupling agent. Thereby, aggregation of the inorganic particles can be suppressed, and good fluidity can be obtained.

[0056] As the coupling agent, for example, various silane-based compounds such as epoxy silane, mercapto silane, amino silane, alkyl silane, ureido silane, and vinyl silane, known coupling agents such as titanium-based compounds, aluminum chelates, and aluminum / zirconium-based compounds can be used.

[0057] [Other components] As long as the effects of the invention are not impaired, the resin composition of the present embodiment may contain other components other than the components described above. Examples of other components include thermosetting resins other than epoxy resins, curing agents other than aromatic amine compounds (A), mold release agents, pigments, flame retardants, adhesion improvers, coupling agents, and other additives. When the resin composition of the present embodiment contains these other components, it may contain only one kind or two or more kinds.

[0058] The resin composition of the present embodiment may contain a solvent (such as an organic solvent). However, from the viewpoints of ease of distribution and handling of the resin composition and suppression of VOC generation in the working environment, it is preferable that the resin composition of the present embodiment does not substantially contain a solvent (such as an organic solvent).

[0059] <Method for producing resin composition> The manufacturing method of the resin composition of the present embodiment can be obtained by mixing the above components by a known method. For example, after blending and uniformly mixing the above components, a method of heating and melt-kneading with a kneading device such as a roll, a conical kneader, or a twin-screw extruder alone or in combination with a roll and other mixing devices, and then granulating or pulverizing is used.

[0060] <Molded article / Method for producing molded article> The molded article of the present embodiment includes a cured product of the above resin composition. Further, the above resin composition is made into a varnish, impregnated with reinforcing fibers, and the resin composition of the present embodiment is impregnated into the reinforcing fibers. Then, it is dried and heat-pressed into a desired shape to cure the resin, which may also be used as a molded article. The curing and molding conditions depend on the shape of the molded article and the like. For example, it can be molded at a mold temperature of 170 to 250 °C, a molding pressure of 0.01 to 10 MPa, and a curing time of 0.5 to 3 hours.

[0061] [Applications] The use of the molded article is not particularly limited. Examples of the use include molded articles for transportation equipment such as automobiles, airplanes, railway vehicles, and ships; various structural members such as office equipment, general machinery, household electrical appliances, and electrical machinery. Further, it can also be applied to impregnation uses and binder uses in which it is used by impregnating various base materials such as organic fibers, metals, and glass. Among them, from the viewpoint of obtaining light weight and good mechanical strength, it is preferably used for molded articles for transportation equipment.

[0062] As described above, the embodiments of the present invention have been described, but these are examples of the present invention, and various configurations other than the above can be adopted. Further, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope capable of achieving the object of the present invention are included in the present invention.

Examples

[0063] Embodiments of the present invention will be described in detail based on examples and comparative examples. Note that the present invention is not limited to the examples.

[0064] (1) Synthesis of aromatic amine compounds (A1) to (A3) [Synthesis Example 1] The aromatic amine compound (A1) represented by the following formula (A1) was synthesized by the following procedure. 4.3 g of 4-aminophenylboronic acid (manufactured by BLDpharm), 4.5 g of 2,7-dibromo-9,9-di-n-octylfluorene (manufactured by Tokyo Chemical Industry Co., Ltd.), 4.5 g of potassium carbonate (manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.5 g of tetrabutylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) were added with 15.0 g of water and 70.0 g of tetrahydrofuran and dissolved. To this solution, 0.2 g of tetrakis(triphenylphosphine)palladium (manufactured by Tokyo Chemical Industry Co., Ltd.) was added under a nitrogen atmosphere, and the mixture was heated to 90° C. in an oil bath and reacted for 8 hours. Thereafter, the organic layer was taken out and the organic solvent was removed, and the obtained solid was purified by a silica gel column (solvent: dichloromethane) to obtain 3.5 g of a reaction product.

[0065]

Chemical formula

[0066] [Synthesis Example 2] The aromatic amine compound (A2) represented by the following formula (A2) was synthesized by the following procedure (Steps 1 to 3).

[0067] 〇Step 1 14.3 g of adamantane ethanol and 29.0 g of carbon tetrabromide were dissolved in 50 ml of dichloromethane. To this solution, a solution prepared by adding 50 ml of dichloromethane to 24.0 g of triphenylphosphine was added dropwise, and the mixture was reacted at room temperature for 2 hours. Thereafter, the organic solvent was removed, petroleum ether was added, and the resulting precipitate was removed by filtration to obtain 17.0 g of a reaction product.

[0068] 〇Step 2 To 8.5 g of the reaction product of Step 1, 4.8 g of 2,7-dibromofluorene (manufactured by Tokyo Chemical Industry Co., Ltd.), 13.3 g of a 17% aqueous sodium hydroxide solution (manufactured by Fujifilm Wako Pure Chemical Corporation), and 0.1 g of tetrabutylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) were added. This mixture was heated to 150 °C in an oil bath under a nitrogen atmosphere and reacted for 2 hours. Thereafter, the organic layer was taken out, the organic solvent was removed, and the obtained solid was washed with acetone to obtain 3.9 g of a reaction product.

[0069] 〇Step 3 To 3.9 g of the reaction product of Step 2, 3.1 g of 4-aminophenylboronic acid (manufactured by BLDpharm), 3.3 g of potassium carbonate (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.3 g of tetrabutylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), 11.0 g of water, and 30.0 g of tetrahydrofuran were added and dissolved. To this solution, 0.1 g of tetrakis(triphenylphosphine)palladium (manufactured by Tokyo Chemical Industry Co., Ltd.) was added under a nitrogen atmosphere, and the mixture was heated to 90 °C in an oil bath and reacted for 8 hours. Thereafter, the organic layer was taken out, the organic solvent was removed, and the obtained solid was purified by a silica gel column (solvent: dichloromethane) to obtain 2.0 g of a reaction product.

[0070] [Chemical formula]

[0071] [Synthesis Example 3] The aromatic amine compound (A3) represented by the following formula (A3) was synthesized according to the following procedure (Steps 1 to 3).

[0072] 〇Step 1 To 4.8 g of 2,7-diaminofluorene dihydrochloride (manufactured by Tokyo Chemical Industry Co., Ltd.), 11.8 g of di-tert-butyl dicarbonate (manufactured by Tokyo Chemical Industry Co., Ltd.), 9.9 g of potassium carbonate (manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.3 g of tetrabutylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), 30.8 g of water and 49.8 g of tetrahydrofuran were added and dissolved. This mixture was heated to 60 °C in an oil bath under a nitrogen atmosphere and reacted for 2 hours. Thereafter, the organic layer was taken out and the organic solvent was removed, and the obtained solid was washed with water and methanol to obtain 6.2 g of a reaction product.

[0073] 〇Step 2 To 4.9 g of the reaction product of Step 1, 8.9 g of the reaction product of Step 1 of [Synthesis Example 2], and 0.3 g of tetrabutylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), 27.6 g of a 17% aqueous sodium hydroxide solution (manufactured by Fujifilm Wako Pure Chemical Corporation) and 27.6 g of mesitylene were added and dissolved. This solution was heated to 150 °C in an oil bath under a nitrogen atmosphere and reacted for 2 hours. Thereafter, the organic layer was taken out and the organic solvent was removed, and the obtained solid was washed with dimethyl sulfoxide and petroleum ether to obtain 4.0 g of a reaction product.

[0074] 〇Step 3 To 2.2 g of the reaction product of Step 2, 6.5 g of trifluoroacetic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was added in an ice bath, and the mixture was reacted at room temperature for 2 hours. Thereafter, the organic solvent was removed, and the obtained solid was washed with petroleum ether to obtain 1.0 g of a reaction product.

[0075] [Chemical Formula]

[0076] [Synthesis Example 4] The phenolic compound (B) represented by the following formula (B) was synthesized by the following procedure. 19.0 g of 4-hydroxyphenylboronic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 25.3 g of 2,7-dibromo-9,9-di-n-octylfluorene (manufactured by Tokyo Chemical Industry Co., Ltd.), 25.4 g of potassium carbonate (manufactured by Tokyo Chemical Industry Co., Ltd.), and 2.5 g of tetrabutylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) were added with 83.8 g of water, 155.0 g of tetrahydrofuran, and 31.0 g of ethanol and dissolved. To this solution, 2.1 g of tetrakis(triphenylphosphine)palladium (manufactured by Tokyo Chemical Industry Co., Ltd.) was added under a nitrogen atmosphere, and the mixture was heated to 90 °C in an oil bath and reacted for 24 hours. Thereafter, the organic layer was taken out and the organic solvent was removed, and the obtained solid was purified by a silica gel column (solvent: dichloromethane) to obtain 16.8 g of a reaction product.

[0077] [Chemical formula]

[0078] (2) Analysis and measurement For the obtained aromatic amine compounds (A1) to (A3), 1 1H-NMR was measured under the following conditions. The results are shown in Figures 1 to 3, respectively. The alphabets a to c in Figures 1 to 3 correspond to the structures represented by the following formulas (A1'), (A2'), and (A3'), respectively.

[0079] < 1 1H-NMR measurement conditions Apparatus: JNM-ECA400 manufactured by JEOL Ltd. Solvent: (A1)(A2) Chloroform-d (A3) DMSO (dimethyl sulfoxide)-d6 Pulse angle: 45° Sample concentration: 3 wt% Number of integrations: 16 times

[0080] [Chemical formula]

[0081] [Chemical formula]

[0082] [Chemical formula]

[0083] 1 From the 1H-NMR measurement, it was confirmed that the aromatic amine compounds (A1) to (A3) have a fluorene structure.

[0084] (3) Preparation of epoxy resin composition [Examples and Comparative Examples] Using the following raw material components, each was mixed so as to have the composition (mass%) shown in Table 1, kneaded on a hot plate at 150 °C for 30 seconds, then taken out to obtain each epoxy resin composition.

[0085] [Raw materials] · Epoxy resin: Tetraglycidyl diaminodiphenylmethane (TGDDM, manufactured by Tokyo Chemical Industry Co., Ltd.) · Curing agent 1: Aromatic amine compound (A1) obtained in Synthesis Example 1 of (1) above · Curing agent 2: Aromatic amine compound (A2) obtained in Synthesis Example 2 of (1) above · Curing agent 3: Aromatic amine compound (A3) obtained in Synthesis Example 3 of (1) above · Curing agent 4: 4,4'-Diaminodiphenyl sulfone (manufactured by Tokyo Chemical Industry Co., Ltd.) · Curing agent 5: Phenol compound (B) obtained in Synthesis Example 4 of (1) above · Curing accelerator: Triphenylphosphine (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0086] (4) Evaluation Each of the obtained resin compositions was cured under the curing conditions shown in Table 1 to obtain molded articles.

[0087] For the obtained molded articles, the following evaluations and measurements were carried out. The results are shown in Table 1. · Specific gravity: The specific gravity of each molded article was determined by the water displacement method. · Bending strength and bending modulus of elasticity: Test pieces with a width of 10 mm, a thickness of 1 mm, and a length of 100 mm were prepared, and the bending strength (MPa) and bending modulus of elasticity (GPa) at 25 °C were measured. · Specific bending strength: It was calculated by dividing the above bending strength by the specific gravity. · Specific bending modulus of elasticity: It was calculated by dividing the above bending modulus of elasticity by the specific gravity.

[0088]

Table 1

Claims

1. An aromatic amine compound represented by the following formula (1). 【Chemical 1】 (In formula (1), R1 and R2 are each independently hydrogen, an amino group or an organic group, and at least one of them is an amino group or an organic group having an amino group. R3 and R4 each independently represent a hydrocarbon group having 4 to 16 carbon atoms.)

2. The aromatic amine compound according to claim 1, wherein in formula (1), both R1 and R2 have an amino group, the aromatic amine compound.

3. The aromatic amine compound according to claim 1 or 2, wherein in formula (1), the amino group is a primary amino group, the aromatic amine compound.

4. The aromatic amine compound according to claim 1 or 2, wherein in formula (1), the organic group is an aliphatic group having 1 to 6 carbon atoms having an amino group, or a divalent aromatic group having an amino group, the aromatic amine compound.

5. The aromatic amine compound according to claim 1 or 2, wherein in formula (1), the hydrocarbon group contains an adamantyl group, the aromatic amine compound.

6. The aromatic amine compound according to claim 1 or 2, wherein in formula (1), the hydrocarbon group is a linear or branched hydrocarbon group, the aromatic amine compound.

7. The aromatic amine compound according to claim 1 or 2, wherein in formula (1), the hydrocarbon group is a saturated hydrocarbon group, the aromatic amine compound.

8. A curing agent using the aromatic amine compound according to claim 1 or 2.

9. An epoxy resin and a curing agent using an aromatic amine compound represented by the following formula (1), an epoxy resin composition. [Chemical Formula 2] (In formula (1), R1 and R2 are each independently hydrogen, an amino group or an organic group, and at least one of them is an amino group or an organic group having an amino group. R3 and R4 each independently represent a hydrocarbon group having 4 to 16 carbon atoms.)

10. The epoxy resin composition according to claim 9, wherein the ratio of the epoxy equivalent in the epoxy resin to the active hydrogen equivalent in the curing agent (epoxy / active hydrogen) is 0.8 or more and 1.5 or less, the epoxy resin composition.

11. A molded article comprising a cured product of the epoxy resin composition according to claim 9 or 10.

12. A transportation equipment molded article comprising a cured product of the epoxy resin composition according to claim 9 or 10.

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