Amino composition and method for producing the same, epoxy resin curing agent, epoxy resin composition and cured product thereof

Abstract

An amino composition and a method for producing the same, an epoxy resin curing agent containing the same, an epoxy resin composition and a cured product thereof, wherein the amino composition contains an amino compound (A) represented by the following general formula (1) and an amino compound (B) represented by the following general formula (3), wherein the molar ratio [(A) / (B)] of the amino compound (A) to the amino compound (B) in the composition is 10 / 90 to 99 / 1. 1 (1)(where R 1 is a monovalent group represented by the following general formula (2). X is a phenylene group. )(wherein the dotted line indicates the presence or absence of a π bond, R 2 ~R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group. * represents a connecting bond. )R 1 ‑NH‑CH2‑X‑CH2‑NH‑R 1 (3)(where R 1 and X are the same as above. )#imgabs0#

Description

Technical Field

[0001] The present invention relates to an amino composition and a preparation method thereof, an epoxy resin curing agent, an epoxy resin composition and a cured product thereof. Background Art

[0002] Polyamine compounds are known as one type of epoxy resin curing agent. Epoxy resin compositions using polyamine compounds as epoxy resin curing agents are also used in the fields of coatings such as anti-corrosion coatings for ships, bridges, and steel structures on land and at sea; lining, reinforcement, and repair materials for concrete structures; building flooring materials; linings for water and sewage systems; paving materials; adhesives; and other civil engineering and construction fields.

[0003] Among them, it is important for epoxy resin compositions for coatings to have good appearance, water resistance, chemical resistance, coating film physical properties, etc. of the resulting coating film.

[0004] Xylylenediamine, a type of aliphatic polyamine compound, exhibits rapid curing properties when used as an epoxy resin curing agent. Furthermore, compared to other aliphatic polyamines, it also exhibits superior low-temperature curing properties and chemical resistance. However, xylylenediamine readily absorbs atmospheric carbon dioxide and water vapor to form carbamates. Therefore, epoxy resin compositions using xylylenediamine as an epoxy resin curing agent tend to exhibit whitening in the coating film, resulting in a deterioration in the coating film appearance.

[0005] As a method for improving the above-mentioned whitening of the coating film, the use of a modified product of xylylenediamine as an epoxy resin curing agent has been studied.

[0006] For example, Patent Document 1 discloses an epoxy resin curing agent that is prepared by reacting a specified maleic acid or fumaric acid derivative with a specified polyoxyalkyleneamine in a specific ratio, and further adding a specified amount of a polyamine compound such as meta-xylylenediamine. Patent Document 1 states that the curing agent is not easily affected by carbon dioxide (such as stickiness or whitening of the surface of the cured product).

[0007] Patent Document 2 discloses a curing agent composition for an epoxy resin, comprising: a polyamine compound, which is a reaction product of a compound having at least one glycidyl group per molecule and a diamine such as xylylenediamine; a specified polyether-modified polysiloxane; and a specified amino-modified polysiloxane. This composition can solve the problem of whitening caused by reduced water resistance and deterioration of appearance, and can provide an epoxy resin composition with excellent surface appearance such as transparency, drying properties (easy drying), adhesion to substrates, and water resistance.

[0008] Epoxy resin curing agents, which are modified polyamines, generally have high viscosities and are therefore often diluted with a non-reactive diluent. However, the use of a non-reactive diluent raises concerns about reduced chemical resistance of coating films of epoxy resin compositions containing such curing agents.

[0009] Therefore, amino compounds obtained by the addition reaction of diamines such as xylylenediamine and alkenyl compounds such as styrene have also been studied as modified products of xylylenediamine having low viscosity (Patent Document 3).

[0010] Patent Document 4 discloses a latent curing agent, which is a reaction product of a polyamine having two or more primary amino groups and furfural, and is mixed into an amine to form a curing agent and polymerize and cure an adhesive. However, the reaction product is an imine (aldimine), which is different from an amino compound. In addition, the latent curing agent describes that the amine produced by hydrolysis of the aldimine, i.e., the aforementioned polyamine, functions as a curing agent, rather than the reaction product itself, which is a modified form of the polyamine, functions as an epoxy resin curing agent.

[0011] Patent Document 5 discloses an agricultural and horticultural fungicide containing as an active ingredient a compound obtained by reducing a compound obtained by 1 mol of xylylenediamine and 2 mol of an aldehyde having a predetermined structure. However, there is no mention of the effect of this compound when used as an epoxy resin curing agent.

[0012] Prior art literature

[0013] Patent Literature

[0014] Patent Document 1: Japanese Patent Application Laid-Open No. 11-35661

[0015] Patent Document 2: Japanese Patent Application Laid-Open No. 2007-186693

[0016] Patent Document 3: Japanese Patent Application Laid-Open No. 2002-161076

[0017] Patent Document 4: Japanese Patent Application Laid-Open No. 10-139849

[0018] Patent Document 5: Japanese Patent Application Laid-Open No. 47-23530 Summary of the Invention

[0019] Problems to be solved by the invention

[0020] The amino compound described in Patent Document 3, which is a modified product of xylylenediamine, has low viscosity and excellent water resistance. However, there is still room for improvement in the aqueous methanol resistance of the coating film of the epoxy resin composition obtained by using the amino compound as an epoxy resin curing agent.

[0021] The present invention aims to provide an amino composition having low viscosity and capable of forming a coating film having excellent aqueous methanol resistance when used as an epoxy resin curing agent, a method for producing the same, an epoxy resin curing agent containing the same, an epoxy resin composition, and a cured product thereof.

[0022] Solutions for solving problems

[0023] The present inventors have discovered that an amino composition containing a modified diamine having a predetermined structure at a predetermined ratio can solve the above-mentioned problems.

[0024] That is, the present invention relates to the following.

[0025] [1] An amino composition comprising an amino compound (A) represented by the following general formula (1) and an amino compound (B) represented by the following general formula (3), wherein the molar ratio [(A) / (B)] of the amino compound (A) to the amino compound (B) in the composition is 10 / 90 to 99 / 1.

[0026] NH2-CH2-X-CH2-NH-R 1 (1)

[0027] (Where R 1 is a monovalent group represented by the following general formula (2). X is a phenylene group.

[0028]

[0029] (where the dashed line indicates the presence or absence of a π bond, R 2 ~R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group. * represents a connecting bond.

[0030] R 1 -NH-CH2-X-CH2-NH-R 1 (3)

[0031] (Where R 1 and X are the same as above.)

[0032] [2] An epoxy resin curing agent comprising the amino composition described in [1].

[0033] [3] An epoxy resin composition comprising an epoxy resin and the epoxy resin curing agent described in [2] above.

[0034] [4] A cured product, which is a cured product of the epoxy resin composition described in [3].

[0035] [5] The method for producing an amino composition according to the above-mentioned [1], which comprises the following steps (1) and (2) in this order.

[0036] Step (1): a step of reacting a diamine represented by the following general formula (4) with an aldehyde compound represented by the following general formula (5) to obtain an imine;

[0037] Step (2): a step of reducing the imine obtained in the above step (1).

[0038] NH2-CH2-X-CH2-NH2(4)

[0039] (Wherein, X is the same as above.)

[0040]

[0041] (Where R 2 ~R 4 Same as above.)

[0042] [6] The method for producing an amino composition according to [5], wherein in the step (1), 0.8 to 1.8 mol of the aldehyde compound represented by the general formula (5) is reacted with 1 mol of the diamine represented by the general formula (4).

[0043] Effects of the Invention

[0044] The present invention provides an amino composition having low viscosity and capable of forming a coating film having excellent aqueous methanol resistance when used as an epoxy resin curing agent, a method for producing the same, an epoxy resin curing agent containing the same, an epoxy resin composition, and a cured product thereof. DETAILED DESCRIPTION

[0045] [Amino composition]

[0046] The amino composition of the present invention contains an amino compound (A) represented by the following general formula (1) and an amino compound (B) represented by the following general formula (3), wherein the molar ratio [(A) / (B)] of the amino compound (A) to the amino compound (B) in the composition is 10 / 90 to 99 / 1.

[0047] NH2-CH2-X-CH2-NH-R 1 (1)

[0048] (Where R 1 is a monovalent group represented by the following general formula (2). X is a phenylene group.

[0049]

[0050] (where the dashed line indicates the presence or absence of a π bond, R 2 ~R 4Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group. * represents a connecting bond.

[0051] R 1 -NH-CH2-X-CH2-NH-R 1 (3)

[0052] (Where R 1 and X are the same as above.)

[0053] The epoxy resin curing agent containing the amino composition of the present invention has low viscosity, and further, when an epoxy resin composition containing the epoxy resin curing agent is used, a coating film having excellent resistance to aqueous methanol can be formed.

[0054] The reason why the amino composition of the present invention can obtain the above-mentioned effects is not clear, but is considered as follows.

[0055] The amino composition of the present invention is obtained by reducing the reactant (imines) of benzylenediamine and furfural or its derivatives. From this viewpoint, it can be said that it is a modified product of benzylenediamine. It is believed that in the above-mentioned manufacturing method, by using benzylenediamine as the reaction raw material of the amino composition, and then introducing an aromatic substituent such as a furan ring as a substituent of the amino group in the benzylenediamine, the hydrophobicity is improved, and the water resistance of the coating film is improved. In addition, it is believed that if benzylenediamine is usually modified with an epoxy compound, it will become high-viscosity, but by modifying benzylenediamine with furfural or its derivatives, the viscosity increase can be suppressed. Furthermore, it is believed that the amino composition of the present invention does not need to add a non-reactive diluent to make it low-viscosity. Therefore, in the coating film of the epoxy resin composition in which the amino composition is used as an epoxy resin curing agent, the reduction of the resistance to aqueous methanol caused by containing a non-reactive diluent can be suppressed.

[0056] The amino composition of the present invention contains an amino compound (A) represented by the aforementioned general formula (1) and an amino compound (B) represented by the aforementioned general formula (3) at a predetermined ratio. The amino compound (A) is a compound obtained by reducing an imine, which is a reactant obtained by reacting the aforementioned diamine with an aldehyde compound at a molar ratio of 1 / 1 (hereinafter, this compound may be referred to as a "1-adduct"). The amino compound (B) is a compound obtained by reducing an imine, which is a reactant obtained by reacting the aforementioned diamine with an aldehyde compound at a molar ratio of 1 / 2 (hereinafter, this compound may be referred to as a "2-adduct").

[0057] Patent Document 5 discloses an amino compound (B) obtained by reducing a reaction product obtained by reacting xylylenediamine with furfural at a molar ratio of 1 / 2. However, the amino composition of the present invention containing the amino compound (A) as a monoadduct at a high ratio, when used as an epoxy resin curing agent, exhibits superior methanol resistance to the resulting epoxy resin coating film compared to the amino compound (B) as a diadduct.

[0058] <Amino compound (A)>

[0059] The amino composition of the present invention contains an amino compound (A) represented by the following general formula (1).

[0060] NH2-CH2-X-CH2-NH-R 1 (1)

[0061] (Where R 1 is a monovalent group represented by the following general formula (2). X is a phenylene group.

[0062]

[0063] (where the dashed line indicates the presence or absence of a π bond, R 2 ~R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group. * represents a connecting bond.

[0064] In the general formula (1), X is a phenylene group, which is any of 1,2-phenylene, 1,3-phenylene, and 1,4-phenylene. From the perspectives of improving low viscosity, rapid curing when used as an epoxy resin curing agent, and the hardness, appearance, water resistance, and aqueous methanol resistance of the resulting epoxy resin composition coating film, X is preferably 1,3-phenylene or 1,4-phenylene, and more preferably 1,3-phenylene.

[0065] In the general formula (2), the dotted line indicates the presence or absence of a π bond. The dotted line preferably indicates the presence of a π bond, but may also include a case where a portion of the π bond is reduced to eliminate the π bond.

[0066] In the above general formula (2), R 2 ~R 4 The alkyl group in is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.

[0067] From the viewpoint of improving low viscosity, rapid curing property when used as epoxy resin curing agent, hardness, appearance, water resistance and aqueous methanol resistance of the coating film of the obtained epoxy resin composition, R 2 ~R 4 It is preferably a hydrogen atom, a methyl group or a hydroxymethyl group, more preferably a hydrogen atom or a methyl group, and further preferably, R2 ~R 4 All hydrogen atoms, or R 2 is methyl and R 3 and R 4 is a hydrogen atom, and more preferably R 2 ~R 4 All are hydrogen atoms.

[0068] <Amino compound (B)>

[0069] The amino composition of the present invention contains an amino compound (B) represented by the following general formula (3).

[0070] R 1 -NH-CH2-X-CH2-NH-R 1 (3)

[0071] (Where R 1 and X are the same as above.)

[0072] In the above general formula (3), R 1 It is a monovalent group represented by the aforementioned general formula (2), and its preferred embodiment is the same as described above.

[0073] In the general formula (3), X is a phenylene group, which is any of 1,2-phenylene, 1,3-phenylene, and 1,4-phenylene. From the perspectives of improving low viscosity, rapid curing when used as an epoxy resin curing agent, and the hardness, appearance, water resistance, and aqueous methanol resistance of the resulting epoxy resin composition coating film, X is preferably 1,3-phenylene or 1,4-phenylene, and more preferably 1,3-phenylene.

[0074] From the viewpoint of improving low viscosity, rapid curing properties when used as an epoxy resin curing agent, and the hardness, appearance, water resistance, and aqueous methanol resistance of the coating film of the resulting epoxy resin composition, the molar ratio [(A) / (B)] of the amino compound (A) to the amino compound (B) in the aforementioned amino composition is 10 / 90 to 99 / 1, preferably 20 / 80 to 99 / 1, more preferably 30 / 70 to 99 / 1, further preferably 40 / 60 to 99 / 1, and even more preferably 50 / 50 to 99 / 1.

[0075] The above molar ratio can be specifically determined by the method described in the Examples.

[0076] The amino composition may contain, in addition to the amino compound (A) and the amino compound (B), by-products or unreacted raw materials, such as a diamine (xylylenediamine) represented by the general formula (4) described later. However, from the viewpoint of improving low viscosity, rapid curing properties when used as an epoxy resin curing agent, and the hardness, appearance, water resistance, and aqueous methanol resistance of the resulting epoxy resin composition coating film, the total content of the amino compound (A) and the amino compound (B) in the amino composition is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 98% by mass or more, and is 100% by mass or less.

[0077] Furthermore, from the viewpoint of improving the hardness, appearance, water resistance, and aqueous methanol resistance of the resulting epoxy resin composition coating film, the content of the unreacted raw material, xylylenediamine, in the amino composition is preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less.

[0078] The total content of the amino compound (A) and the amino compound (B) in the amino composition and the content of the unreacted raw material, ie, xylylenediamine, can be measured by gas chromatography (GC) analysis.

[0079] From the perspective of obtaining a low-viscosity epoxy resin curing agent, the viscosity of the amino composition at 25°C is preferably 500 mPa·s or less, more preferably 300 mPa·s or less, further preferably 200 mPa·s or less, further preferably 100 mPa·s or less, further preferably 90 mPa·s or less, and typically 10 mPa·s or more.

[0080] The viscosity of the amino composition at 25° C. can be measured using an E-type viscometer, specifically, by the method described in Examples.

[0081] [Method for producing amino composition]

[0082] The method for producing the amino composition of the present invention (hereinafter also referred to as "the production method of the present invention") preferably comprises the following steps (1) and (2) in this order.

[0083] Step (1): A step of reacting a diamine represented by the following general formula (4) with an aldehyde compound represented by the following general formula (5) to obtain an imine.

[0084] Step (2): a step of reducing the imine obtained in the above step (1).

[0085] NH2-CH2-X-CH2-NH2(4)

[0086] (Wherein, X is the same as above.)

[0087]

[0088] (Where R 2 ~R 4 Same as above.)

[0089] <Process (1)>

[0090] In step (1), the diamine represented by the above-mentioned general formula (4) and the aldehyde compound represented by the above-mentioned general formula (5) are reacted to obtain an imine.

[0091] In the general formula (4), X is a phenylene group, which is any of 1,2-phenylene, 1,3-phenylene, and 1,4-phenylene. From the perspectives of improving low viscosity, rapid curing when used as an epoxy resin curing agent, and the hardness, appearance, water resistance, and aqueous methanol resistance of the resulting epoxy resin composition coating film, X is preferably 1,3-phenylene or 1,4-phenylene, and more preferably 1,3-phenylene.

[0092] Specific examples of the diamine represented by the general formula (4) are at least one selected from the group consisting of o-xylylenediamine, m-xylylenediamine, and p-xylylenediamine. From the viewpoint of improving low viscosity, rapid curing properties when used as an epoxy resin curing agent, and the hardness, appearance, water resistance, and aqueous methanol resistance of the resulting epoxy resin composition coating film, at least one selected from the group consisting of m-xylylenediamine and p-xylylenediamine is preferred, m-xylylenediamine and a mixture of m-xylylenediamine and p-xylylenediamine are more preferred, and m-xylylenediamine is even more preferred.

[0093] R in the above general formula (5) 2 ~R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group. 2 ~R 4 The alkyl group in is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.

[0094] From the viewpoint of improving the low viscosity of the amino compound and amino composition obtained, the rapid curing property when used as an epoxy resin curing agent, the hardness, appearance, water resistance and aqueous methanol resistance of the coating film of the epoxy resin composition obtained, R 2 ~R 4 It is preferably a hydrogen atom, a methyl group or a hydroxymethyl group, more preferably a hydrogen atom or a methyl group, and further preferably, R 2 ~R 4 All hydrogen atoms, or R 2 is methyl and R 3 and R 4 is a hydrogen atom, and more preferably R 2 ~R4 All are hydrogen atoms.

[0095] Specific examples of the aldehyde compound represented by the general formula (5) include furfural, 3-methylfurfural, 4-methylfurfural, 5-methylfurfural, 3-hydroxymethylfurfural, 4-hydroxymethylfurfural, 5-hydroxymethylfurfural, 4,5-dimethylfurfural, 3-ethylfurfural, 4-ethylfurfural, 5-ethylfurfural, 3-propylfurfural, 4-propylfurfural, 5-propylfurfural, 3-butylfurfural, 4-butylfurfural, 5-butylfurfural, etc. Among them, one kind or two or more kinds can be used.

[0096] Among the above, from the viewpoint of improving the low viscosity of the obtained amino compound and amino composition, the rapid curing property when used as an epoxy resin curing agent, the hardness, appearance, water resistance and aqueous methanol resistance of the coating film of the obtained epoxy resin composition, the aldehyde compound represented by the general formula (5) is preferably at least one selected from the group consisting of furfural, 3-methylfurfural, 4-methylfurfural, 5-methylfurfural, 3-hydroxymethylfurfural, 4-hydroxymethylfurfural, 5-hydroxymethylfurfural and 4,5-dimethylfurfural, more preferably at least one selected from the group consisting of furfural and 5-methylfurfural, and even more preferably furfural.

[0097] In step (1), from the viewpoint of obtaining the amino compound represented by the aforementioned general formula (1) and the amino composition containing the amino compound in high yield, the aldehyde compound represented by the aforementioned general formula (5) is reacted in an amount of 0.8 to 1.8 mol, preferably 1.0 to 1.8 mol, more preferably 1.0 to 1.5 mol, and even more preferably 1.0 to 1.3 mol, relative to 1 mol of the diamine represented by the aforementioned general formula (4).

[0098] The reaction of the diamine represented by the general formula (4) and the aldehyde compound represented by the general formula (5) is preferably carried out under heating and stirring conditions. From the perspective of improving reaction efficiency and suppressing thermal degradation of the diamine and aldehyde compound as raw materials, the reaction temperature is preferably in the range of 40 to 120°C, more preferably 50 to 95°C. The reaction time can be appropriately selected and is generally in the range of 15 minutes to 6 hours.

[0099] The above reaction can be carried out in a reaction solvent or without a solvent.

[0100] The above reaction in step (1) yields an imine, a reaction product of the diamine represented by the general formula (4) and the aldehyde compound represented by the general formula (5). The reaction product obtained in step (1) may be purified or directly supplied to step (2) without purification.

[0101] <Process (2)>

[0102] In step (2), the imine obtained in step (1) is reduced and converted into an amine. The reduction of the imine is preferably carried out by hydrogenation (hydrogenation) in the presence of a catalyst under heating and pressure conditions.

[0103] As the catalyst used in step (2), known hydrogenation catalysts can be listed, for example, supported heterogeneous hydrogenation catalysts in which metals such as Ni, Pt, Pd, and Ru are supported on carbon, silica, alumina, diatomaceous earth, etc.; so-called Ziegler-type hydrogenation catalysts using organic acid salts of Ni, Co, Fe, Cr, etc. or transition metal salts such as acetylacetonate and reducing agents such as organoaluminum; homogeneous hydrogenation catalysts such as so-called organometallic complexes such as organometallic compounds of Ti, Ru, Rh, and Zr, etc.

[0104] From the viewpoint of improving reaction efficiency and suppressing side reactions, the temperature during the hydrogenation reaction is preferably 0°C or higher, more preferably 10°C or higher, and even more preferably 20°C or higher, and is preferably 200°C or lower, more preferably 150°C or lower, and even more preferably 100°C or lower.

[0105] From the viewpoint of improving reaction efficiency and suppressing side reactions, the pressure during the hydrogenation reaction is preferably 0.01 MPaG or higher, more preferably 0.1 MPaG or higher, further preferably 0.3 MPaG or higher, and is preferably 10 MPaG or lower, more preferably 3 MPaG or lower.

[0106] The reaction time is not particularly limited, but is preferably 3 minutes or longer, more preferably 10 minutes or longer, and even more preferably 30 minutes or longer, and is preferably 24 hours or shorter, more preferably 12 hours or shorter, and even more preferably 8 hours or shorter.

[0107] The hydrogenation reaction can also be carried out in the presence of a solvent. The solvent is not particularly limited as long as it does not interfere with the hydrogenation reaction. Examples include hydrocarbon solvents such as aliphatic hydrocarbons such as pentane, hexane, isopentane, heptane, octane, and isooctane; alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane; and aromatic hydrocarbons such as toluene, ethylbenzene, and xylene. These solvents may be used alone or in combination of two or more.

[0108] After the hydrogenation reaction, the catalyst is removed from the obtained reaction solution, and purification by distillation is performed as needed to obtain the amino compound or amino composition of the present invention.

[0109] It should be noted that the method for producing the amino composition is not limited to the method described above. For example, the composition can also be produced by the following methods: a method of reacting the diamine represented by the general formula (4) with the amine represented by the general formula (6) in the presence of a catalyst for deamination; a method of reacting the diamine represented by the general formula (4) with the alcohol represented by the general formula (7) in the presence of a catalyst under a hydrogen atmosphere; or a method of reacting the diamine represented by the general formula (4) with the chloride represented by the general formula (8). In this case, the compounds represented by the general formulas (6) to (8) are reacted in an amount of preferably 0.8 to 1.8 mol, more preferably 1.0 to 1.8 mol, even more preferably 1.0 to 1.5 mol, and even more preferably 1.0 to 1.3 mol, per 1 mol of the diamine represented by the general formula (4).

[0110]

[0111] (In formulas (6) to (8), R 2 ~R 4 Same as above.)

[0112] [Epoxy resin curing agent]

[0113] The epoxy resin curing agent of the present invention contains the amino composition of the present invention. The epoxy resin curing agent has low viscosity and, when used in an epoxy resin composition, can form a coating film having excellent aqueous methanol resistance.

[0114] From the viewpoint of improving low viscosity, rapid curing properties, hardness, appearance, water resistance, and aqueous methanol resistance of the resulting epoxy resin composition coating film, the content of the amino composition in the epoxy resin curing agent is preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and is 100% by mass or less.

[0115] The epoxy resin curing agent of the present invention may contain other curing agent components in addition to the aforementioned amino composition. In this specification, the curing agent component refers to a component contained in the epoxy resin curing agent and having two or more active hydrogen atoms that can react with epoxy groups in the epoxy resin.

[0116] Examples of the other curing agent component include amine curing agents, phenol curing agents, and acid anhydride curing agents. From the viewpoint of rapid curing properties, amine curing agents are preferred.

[0117] Examples of the amine curing agent include polyamine compounds other than the aforementioned amino composition or modified products thereof. The polyamine compound is not particularly limited as long as it has at least two amino groups in its molecule.

[0118] Examples of the polyamine compound or its modified product include: chain aliphatic polyamine compounds such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexamethylenediamine, 2-methylpentamethylenediamine, and trimethylhexamethylenediamine; 1,2-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, and menthanediamine; diamine), isophorone diamine, norbornane diamine, tricyclodecane diamine, adamantane diamine, diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-3,6-diethylcyclohexane, diaminodiethylmethylcyclohexane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylmethane and other polyamine compounds with alicyclic structures; o-phenylenediamine, m-phenylenediamine and p-phenylenediamine, phenylenediamine, diaminodiphenylmethane, diaminodiphenylmethane Polyamine compounds having an aromatic ring such as 1,2-diphenylsulfone; polyamine compounds having a heterocyclic structure such as N-aminomethylpiperazine and N-aminoethylpiperazine; polyether polyamine compounds; reaction products obtained by reacting the above polyamine compounds with an epoxy compound having at least one epoxy group, an unsaturated hydrocarbon compound, a carboxylic acid or a derivative thereof; Mannich reaction products obtained by reacting the above polyamine compounds with a phenol compound and an aldehyde compound; ketimines obtained by reacting the above polyamine compounds with a ketone compound; etc. These may be used alone or in combination of two or more.

[0119] When other curing agent components are used, the content of the other curing agent components in the epoxy resin curing agent is preferably 1% by mass or more, more preferably 5% by mass or more. The upper limit of this content is within a range that does not impair the effects of the present invention, and is preferably 70% by mass or less, more preferably 50% by mass or less, further preferably 40% by mass or less, even more preferably 30% by mass or less, and even more preferably 20% by mass or less.

[0120] The epoxy resin curing agent of the present invention may further contain a known curing accelerator, a non-reactive diluent, and the like.

[0121] Examples of the curing accelerator include phenol compounds, organic acids, organic acid salts, tertiary amines, quaternary ammonium salts, imidazoles, organophosphorus compounds, quaternary phosphonium salts, diazabicycloolefins, organometallic salt compounds, boron compounds, and metal halides.

[0122] Examples of the non-reactive diluent include benzyl alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, and aromatic hydrocarbon formaldehyde resins. Among these, one kind or two or more kinds may be used.

[0123] However, from the perspective of improving the aqueous methanol resistance of the resulting epoxy resin composition coating film, the epoxy resin curing agent of the present invention preferably contains a low content of the non-reactive diluent. The content of the non-reactive diluent in the epoxy resin curing agent is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, even more preferably 1% by mass or less, and even more preferably 0% by mass.

[0124] To improve low viscosity, rapid curing properties, and the hardness, appearance, water resistance, and aqueous methanol resistance of the resulting epoxy resin composition coating film, the active hydrogen equivalent weight of the epoxy resin curing agent is preferably 80 or greater. To improve curability, it is preferably 150 or less, and more preferably 120 or less. The active hydrogen equivalent weight (hereinafter also referred to as "AHEW") in this specification refers to the mass of active hydrogen derived from amino groups per 1 mol of the epoxy resin curing agent. The AHEW of the curing agent can be determined by the amine value.

[0125] [Epoxy resin composition]

[0126] The epoxy resin composition of the present invention comprises an epoxy resin and the aforementioned epoxy resin curing agent. The epoxy resin composition has a fast curing speed and the resulting coating film has excellent hardness, water resistance, and aqueous methanol resistance.

[0127] Epoxy resin

[0128] The epoxy resin used as the main component of the epoxy resin composition can be any of saturated or unsaturated aliphatic compounds, alicyclic compounds, aromatic compounds, and heterocyclic compounds. From the perspective of improving the curing speed and forming a coating film with high hardness, appearance, water resistance, and resistance to aqueous methanol, epoxy resins containing aromatic or alicyclic structures in the molecule are preferred.

[0129] Specific examples of the epoxy resin include at least one resin selected from the group consisting of epoxy resins having glycidylamino groups derived from m-xylylenediamine, epoxy resins having glycidylamino groups derived from p-xylylenediamine, epoxy resins having glycidylamino groups derived from 1,3-bis(aminomethyl)cyclohexane, epoxy resins having glycidylamino groups derived from 1,4-bis(aminomethyl)cyclohexane, epoxy resins having glycidylamino groups derived from diaminodiphenylmethane, epoxy resins having glycidylamino groups and / or glycidyloxy groups derived from p-aminophenol, epoxy resins having glycidyloxy groups derived from bisphenol A, epoxy resins having glycidyloxy groups derived from bisphenol F, epoxy resins having glycidyloxy groups derived from phenol novolacs, and epoxy resins having glycidyloxy groups derived from resorcinol. Two or more of these epoxy resins may be used in combination.

[0130] Among the above, from the viewpoint of improving the curing speed and obtaining a coating film having high hardness, water resistance, and aqueous methanol resistance, the epoxy resin preferably contains as a main component at least one selected from the group consisting of an epoxy resin having a glycidyl amino group derived from m-xylylenediamine, an epoxy resin having a glycidyl amino group derived from p-xylylenediamine, an epoxy resin having a glycidyl ether group derived from bisphenol A, and an epoxy resin having a glycidyl ether group derived from bisphenol F. From the viewpoint of improving the curing speed, forming a coating film having high hardness, appearance, water resistance, and aqueous methanol resistance, as well as from the viewpoint of availability and cost-effectiveness, the epoxy resin containing as a main component an epoxy resin having a glycidyl ether group derived from bisphenol A is more preferred.

[0131] It should be noted that the "main component" herein may contain other components within the scope of the present invention, and is preferably 50 to 100 mass %, more preferably 70 to 100 mass %, and even more preferably 90 to 100 mass % of the total.

[0132] To improve workability, the epoxy resin as the main agent may contain a reactive diluent other than the above-mentioned epoxy resin. Examples of such reactive diluents include low molecular weight compounds having at least one epoxy group, such as aromatic monoglycidyl ethers such as phenyl glycidyl ether and cresyl glycidyl ether; alkyl monoglycidyl ethers such as butyl glycidyl ether, hexyl glycidyl ether, octyl glycidyl ether, decyl glycidyl ether, lauryl glycidyl ether, and tetradecyl glycidyl ether; and diglycidyl ethers of aliphatic diols such as 1,3-propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexanediol diglycidyl ether.

[0133] The reactive diluents may be used alone or in combination of two or more.

[0134] Regarding the content ratio of the epoxy resin and the epoxy resin curing agent in the epoxy resin composition of the present invention, the ratio of the number of active hydrogen atoms derived from the amino groups in the epoxy resin curing agent to the number of epoxy groups in the epoxy resin (the number of active hydrogen atoms derived from the amino groups in the epoxy resin curing agent / the number of epoxy groups in the epoxy resin) is preferably 1 / 0.5 to 1 / 2, more preferably 1 / 0.75 to 1 / 1.5, and even more preferably 1 / 0.8 to 1 / 1.2.

[0135] The content of the epoxy resin and epoxy resin curing agent in the epoxy resin composition is not limited as long as the ratio of the number of active hydrogen atoms derived from the amino groups in the epoxy resin curing agent to the number of epoxy groups in the epoxy resin is preferably within the aforementioned range. However, from the viewpoint of improving the curing speed and forming a coating film having high hardness, appearance, water resistance, and aqueous methanol resistance, the following range is preferred.

[0136] The content of the epoxy resin in the epoxy resin composition is preferably 40% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, and is preferably 80% by mass or less, more preferably 75% by mass or less.

[0137] The content of the epoxy resin curing agent in the epoxy resin composition is preferably 20% by mass or more, more preferably 25% by mass or more, and is preferably 60% by mass or less, more preferably 50% by mass or less, and further preferably 40% by mass or less.

[0138] The content of the epoxy resin curing agent in the epoxy resin composition is preferably 20 to 60 parts by mass, more preferably 30 to 60 parts by mass, and even more preferably 40 to 60 parts by mass relative to 100 parts by mass of the epoxy resin as the main agent.

[0139] From the viewpoint of improving low viscosity, rapid curing properties, hardness of the coating film, appearance, water resistance and resistance to aqueous methanol, the total content of the epoxy resin and the epoxy resin curing agent in the epoxy resin composition is preferably 40% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and is 100% by mass or less.

[0140] The epoxy resin composition of the present invention may further contain modifying components such as fillers and plasticizers; flow regulating components such as thixotropic agents; and other components such as pigments, leveling agents, tackifiers, and elastomer microparticles, depending on the intended use.

[0141] The epoxy resin composition of the present invention may also contain the aforementioned non-reactive diluent and a solvent other than the non-reactive diluent (water and a volatile solvent). The content of the solvent in the epoxy resin composition is preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less.

[0142] <Method for producing epoxy resin composition>

[0143] The epoxy resin composition of the present invention may be produced by mixing an epoxy resin, an epoxy resin curing agent, and other components as needed using known methods and apparatus. The order in which the components of the epoxy resin composition are mixed is also not particularly limited. The epoxy resin curing agent may be prepared before mixing it with the epoxy resin, or the components of the epoxy resin curing agent, other components, and the epoxy resin may be mixed simultaneously.

[0144] [cured material]

[0145] The cured product of the epoxy resin composition of the present invention (hereinafter also referred to as the "cured product of the present invention") is obtained by curing the aforementioned epoxy resin composition by a known method. The curing conditions of the epoxy resin composition are appropriately selected depending on the application and form and are not particularly limited.

[0146] The form of the cured product of the present invention is not particularly limited and can be selected according to the intended use. The cured product of the epoxy resin composition is preferably a film-shaped cured product from the viewpoint of forming a coating film having high hardness, appearance, water resistance, and aqueous methanol resistance.

[0147] <Application>

[0148] The epoxy resin composition of the present invention is preferably used in coating applications such as marine coatings, heavy-duty anti-corrosion coatings, can coatings, pipe interior coatings, exterior coatings, and floor coatings, from the viewpoint of forming coating films having high hardness, appearance, water resistance, and aqueous methanol resistance.

[0149] Example

[0150] The present invention will be described in detail below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. Analyses and evaluations of the amino composition were performed by the following methods.

[0151] Gas chromatography (GC) analysis

[0152] The content ratio of each component in the amino composition was measured by GC analysis. The measurement conditions were as follows.

[0153] Device: "7890B GC" manufactured by Agilent Technologies Japan, Ltd.

[0154] Chromatographic column: Agilent Technologies Japan, Ltd. "CP-Sil 8 CB for Amines" (length 30 m, film thickness 0.25 μm, inner diameter 0.25 mm)

[0155] Column temperature: 40℃ for 10 minutes → 20℃ / minute heating → 250℃ for 10 minutes → 20℃ / minute heating → 300℃ for 10 minutes

[0156] Carrier gas: Helium

[0157] Carrier gas flow rate: 2.2553 mL / min

[0158] Inlet pressure: 22.474 psi (constant pressure mode)

[0159] Detector: FID

[0160] Inlet temperature: 250℃

[0161] Detector temperature: 310°C

[0162] < 1 H-NMR analysis>

[0163] The structures of the components contained in the obtained amino composition were identified by 1 The measurement conditions are as follows.

[0164] Nuclear magnetic resonance spectrometer; AVANCEIII-500 manufactured by Bruker BioSpin

[0165] probe; Double resonance multi-nuclide probe (BBFO Plus Smart probe)

[0166] Deuterated solvent; deuterated chloroform

[0167] Determination of nuclear; 1H

[0168] Measuring temperature; room temperature

[0169] <Composition Analysis of Amino Composition (Molar Ratio of Amino Compound (A) to Amino Compound (B))>

[0170] The molar ratio of the amino compound (A) to the amino compound (B) in the amino composition is adjusted by the above-mentioned conditions. 1 The integrated value of the protons corresponding to the benzyl position of each amino compound was determined by H-NMR analysis, and the molar ratio of the amino compound (A) to the amino compound (B) was calculated from the result.

[0171] <Viscosity measurement>

[0172] The viscosity of the amino composition (curing agent) at 25° C. was measured using an E-type viscometer “TVE-35H Viscometer Cone Plate Type” manufactured by Toki Sangyo Co., Ltd.

[0173] <Determination of Active Hydrogen Equivalent Weight (AHEW)>

[0174] The total amine value and secondary / tertiary amine value of the amino composition (curing agent) were determined using an AT-710S potentiometric automatic titrator manufactured by Kyoto Electrics Manufacturing Co., Ltd., and the AHEW was calculated from the results. The total amine value was measured using a 0.1 mol / L perchloric acid-acetic acid solution (manufactured by Kanto Chemical Co., Ltd.), and the secondary / tertiary amine value was measured using 0.1 mol / L hydrochloric acid (2-propanol).

[0175] <Dry to touch>

[0176] A zinc phosphate-treated steel plate (manufactured by PALTEK CORPORATION; SPCC-SDPB-N144, 0.8 × 70 × 150 mm) was used as a substrate. Each epoxy resin composition was applied to the substrate using an applicator at 23°C and 50% RH to form a coating film (film thickness immediately after application: 200 μm). The coating film was stored at 23°C and 50% RH and evaluated by finger touch after 1 day and 7 days using the following criteria. The results are shown in Table 2.

[0177] Ex: Excellent (no stickiness or fingerprint residue when pressing the thumb with a force of approximately 50N)

[0178] G: Good (no stickiness when the thumb is pressed with a force of about 50N, but fingerprints remain after the touch)

[0179] F: OK (the coating becomes sticky when the thumb is pressed with a force of about 50N)

[0180] P: Poor (uncured)

[0181] Pencil hardness

[0182] The epoxy resin composition was applied to a substrate (zinc phosphate-treated steel sheet) using the same method as above to form a coating film (thickness immediately after coating: 200 μm). The coating film was stored at 23°C and 50% RH, and the pencil hardness was measured after 1 day and 7 days in accordance with JIS K5600-5-4:1999. The results are shown in Table 2.

[0183] Water spot resistance test

[0184] The epoxy resin composition was applied to a substrate (zinc phosphate-treated steel plate) using the same method as described above to form a coating film (thickness immediately after application: 200 μm). The coating film was stored at 23°C and 50% RH. After 1 day and 7 days, 2 to 3 drops of pure water were added to the coating film surface using a dropper. The area was then capped with a 50 mL screw-type vial. After 24 hours, the water was wiped off, and the appearance was visually observed and evaluated according to the following criteria. The results are shown in Table 2.

[0185] Ex: No change at all

[0186] G: There are some minor changes, but there is no problem in using it.

[0187] F: Slightly white

[0188] P: Significant whitening

[0189] <Appearance (Transparency / Gloss)>

[0190] The epoxy resin composition of each example was applied to a substrate (zinc phosphate-treated steel plate) using an applicator in the same manner as above to form a coating film (film thickness immediately after application: 200 μm). The coating film was stored at 23°C and 50% RH. After one day, the appearance was visually observed, and transparency and gloss were evaluated according to the following criteria. The results are shown in Table 2.

[0191] (Transparency)

[0192] Ex: No turbidity

[0193] G: A little cloudy, but no problem in use

[0194] F: Slightly cloudy

[0195] P: White turbidity

[0196] (luster)

[0197] Ex: glossy

[0198] G: The glossiness is slightly reduced, but there is no problem in use

[0199] F: less gloss

[0200] P: Matt

[0201] <RCI drying time (semi-drying)>

[0202] Each epoxy resin composition was applied to a glass plate (25 × 348 × 2.0 mm, manufactured by Taiyu Kizai Co., Ltd.) using a 76 μm applicator at 23°C and 50% RH to form a coating film. The coated glass plate was then placed in a paint drying time meter (manufactured by Taiyu Kizai Co., Ltd.). The streak left by the meter's needle as it scraped across the coating surface was observed, and the time it took to reach semi-drying (the time it took for the needle mark to emerge from the coating to the surface) was measured. The results are shown in Table 2. A shorter time indicates a faster curing rate.

[0203] <Resistance to aqueous methanol>

[0204] The epoxy resin composition of each example was applied to a substrate (zinc phosphate-treated steel plate) using an applicator in the same manner as above to form a coating film (coating film thickness immediately after application: 200 μm). The coating film was stored at 23°C and 50% RH. After 7 days, the uncoated area was sealed with a rust-proof paint ("MILLION PRIMER" and "MILLION CLEAR" manufactured by Kansai Paint Co., Ltd.) to prepare a test piece.

[0205] The test pieces were immersed in a 90% methanol aqueous solution at 23°C. After one week, the appearance of the test pieces was visually observed, and the aqueous methanol resistance was evaluated according to the following criteria. The results are shown in Table 2.

[0206] Ex: No appearance changes

[0207] G: Gloss slightly reduced

[0208] F: Surface roughness and reduced gloss

[0209] P: Bubbling or dissolution of the coating

[0210] Example 1

[0211] (Production of Amino Composition A)

[0212] [Process (1)]

[0213] In a 300 ml separable flask equipped with a stirring device, a thermometer, a nitrogen inlet tube, a dropping funnel, and a cooling tube, 40.0 g (0.3 mol) of m-xylenediamine (MXDA, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added dropwise under a nitrogen stream over 15 to 20 minutes while stirring. After the addition was complete, the temperature was raised to 80°C and the reaction was carried out for 30 minutes. The reaction product was measured. 1 H-NMR and confirmed the aldehyde group derived from furfural 1 The peak of H disappeared, and the reaction was completed. Thereafter, toluene was added to the reaction product, and water in the system was removed by azeotropic dehydration to obtain an imine as a reaction product of m-xylylenediamine and furfural in a molar ratio of 1 / 1.

[0214] [Process (2)]

[0215] Into an autoclave (230 mL capacity, material: SUS316L) equipped with a stirrer and a heater were placed 29.7 g of the imine obtained in step (1), 30 g of toluene, and 0.3 g of a 5% Pd / C catalyst (manufactured by NECHEMCAT CORPORATION; STD type) as a hydrogenation catalyst, and the gas phase was replaced with hydrogen. The temperature was then raised while stirring, and after the liquid temperature reached 80°C over 1 hour, the pressure was increased to 1 MPaG with hydrogen. The reaction was then continued for 1.5 hours while hydrogen was supplied at intervals to maintain the pressure at 1 MPaG at a liquid temperature of 80°C. The resulting reaction solution was filtered, the hydrogenation catalyst removed, and then concentrated under vacuum to obtain 28.8 g of amino composition a, which was a reduced product of the imine obtained in step (1). Residual m-xylylenediamine was removed from the resulting amino composition a by vacuum distillation to obtain 26.2 g of amino composition A.

[0216] The amino composition A obtained was subjected to GC analysis under the above conditions. 1 H-NMR analysis was performed to calculate the composition ratios listed in Table 1. GC analysis used a solution prepared by dissolving 0.1 g of amino composition A in 1 g of methanol as a measurement sample. The GC area ratios listed in Table 1 refer to the area percentages of the components detected by gas chromatography.

[0217] In amino composition A, the content of the amino compound represented by general formula (1) (amino compound (A)) was 73% by GC area ratio, the content of the amino compound represented by general formula (3) (amino compound (B)) was 27% by GC area ratio, and the molar ratio (A / B) of amino compound (A) to amino compound (B) was 84 / 16. The viscosity and AHEW of amino composition A at 25°C are shown in Table 2.

[0218] The amino composition A was subjected to the above conditions. 1 H-NMR analysis revealed that the amino compound represented by the general formula (1) (amino compound (A)) in the amino composition A contained a compound represented by the following structural formula (A1) as the main component, and the amino compound represented by the general formula (3) (amino compound (B)) contained a compound represented by the following structural formula (B1) as the main component. Furthermore, the amino compound (A) contained, in addition to the compound represented by the following structural formula (A1), a trace amount of a compound in which the unsaturated bonds of the furan ring in the compound were partially or completely reduced, and the amino compound (B) contained, in addition to the compound represented by the following structural formula (B1), a trace amount of a compound in which the unsaturated bonds of the furan ring in the compound were partially or completely reduced.

[0219]

[0220] The compound represented by structural formula (A1) 1 H-NMR chemical shift: δ7.36ppm (dd, 1H, -OC H =), δ7.30~7.20ppm (m, 4H, -C6 H4 -), δ6.31ppm (dd, 1H, -O-CH=C H -), δ6.18ppm (dd, 1H, -O-CH=CH-C H =), δ3.85ppm(s, 2H, -C H2 -NH2), δ3.78ppm(d, 4H, -NH-C H2 -C4H3O, -C6H4-C H2 -NH-), δ1.58ppm(s, 3H, -N H -、-NH2 )

[0221]

[0222] The compound represented by structural formula (B1) 1 H-NMR chemical shift: δ7.36ppm (dd, 2H, -OC H =), δ7.30~7.20ppm (m, 4H, -C6 H4 -), δ6.31ppm (dd, 2H, -O-CH=C H -), δ6.18ppm (dd, 2H, -O-CH=CH-C H =), δ3.78ppm(d, 8H, -NH-C H2 -C4H3O, -C6H4-C H2 -NH-), δ1.75ppm(s, 2H, -N H -)

[0223] (Preparation and Evaluation of Epoxy Resin Compositions)

[0224] A liquid epoxy resin having a glycidyl ether group derived from bisphenol A ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 186 g / equivalent) was used as the main epoxy resin, and the amino composition A was used as the epoxy resin curing agent.

[0225] The epoxy resin and epoxy resin curing agent were blended in the amounts shown in Table 2, and stirred and mixed at 23°C to prepare an epoxy resin composition. The ratio of the number of active hydrogens in the epoxy resin curing agent to the number of epoxy groups in the base epoxy resin (number of active hydrogens in the epoxy resin curing agent / number of epoxy groups in the base epoxy resin) was adjusted to 1 / 1.

[0226] The epoxy resin compositions thus obtained were subjected to various evaluations according to the aforementioned methods. The results are shown in Table 2.

[0227] Example 2

[0228] (Production of Amino Composition B)

[0229] In step (1) of Example 1, amino composition B was produced by the same method as in Example 1, except that the amount of meta-xylylenediamine charged was changed to 40.9 g (0.3 mol) and the amount of furfural charged was changed to 43.2 g (0.45 mol). The composition of amino composition B is shown in Table 1, and the viscosity and AHEW at 25°C are shown in Table 2.

[0230] (Preparation and Evaluation of Epoxy Resin Compositions)

[0231] In Example 1, except that amino composition B was used instead of amino composition A, the epoxy resin composition was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0232] Example 3

[0233] (Production of Amino Composition C)

[0234] In step (1) of Example 1, an amino composition C was produced by the same method as in Example 1, except that the feed amount of m-xylylenediamine was changed to 40.9 g (0.3 mol) and 33.0 g (0.3 mol) of 5-methylfurfural (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of furfural. The composition of the amino composition C is shown in Table 1, and the viscosity and AHEW at 25°C are shown in Table 2.

[0235] The amino composition C was subjected to the above conditions. 1 H-NMR analysis revealed that the amino compound represented by the general formula (1) in the amino composition C (amino compound (A)) was a compound represented by the following structural formula (A2), and the amino compound represented by the general formula (3) (amino compound (B)) was a compound represented by the following structural formula (B2).

[0236]

[0237] The compound represented by structural formula (A2) 1 H-NMR chemical shift: δ7.30~7.19ppm(m、4H、-C6 H4 -), δ6.04ppm(dd, 1H, -OC(CH3)=C H -), δ5.89~5.88ppm(m, 1H, -OC(CH3)=CH-C H -), δ3.86ppm(s, 2H, -C6H4-C H2 -NH2,), δ3.78ppm(d, 2H, -C6H4-C H2 -NH-), δ3.73ppm, (d, 2H, -NH-C H2 -C4H2O-CH3), δ2.27ppm(s, 3H, -C H3 )、δ1.55ppm(s、3H、-N H -、-N H2 )

[0238]

[0239] The compound represented by structural formula (B2) 1H-NMR chemical shift: δ7.30~7.19ppm(m、4H、-C6 H4 -), δ6.04ppm(dd, 2H, -OC(CH3)=C H -), δ5.89~5.88ppm(m, 2H, -OC(CH3)=CH-C H -), δ3.78ppm(d, 4H, -C6H4-C H2 -NH2), δ3.73ppm, (d, 4H, -NH-C H2 -C4H2O-CH3), δ2.27ppm(s, 6H, -C H3 )、δ1.67ppm(s、2H、-N H -、-N H2 )

[0240] (Preparation and Evaluation of Epoxy Resin Compositions)

[0241] In Example 1, except that amino composition C was used instead of amino composition A, the epoxy resin composition was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0242] Comparative Example 1

[0243] (Production of Comparative Amino Composition D)

[0244] In a 300 ml separable flask equipped with a stirrer, thermometer, nitrogen inlet tube, dropping funnel, and condenser, 40.8 g of m-xylylenediamine (MXDA, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was placed. Under a nitrogen stream, 22.3 g of a polyfunctional epoxy resin derived from bisphenol A and having glycidyl ether groups (jER828, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 186 g / equivalent) was added dropwise over 1 hour while stirring (the number of active hydrogen atoms in the m-xylylenediamine was 10 / 1 to the number of epoxy groups in the epoxy compound). After the addition, the temperature was raised to 80°C and the reaction was allowed to proceed for 2 hours to obtain an MXDA-jER828 reaction composition. Benzyl alcohol was added to the reaction composition in an amount of 40% by mass to dilute the reaction composition, yielding a 60% by mass solution of the reaction composition, Comparative Amino Composition D. The AHEW of Comparative Amino Composition D (including the total amount of benzyl alcohol) was 98. Table 2 shows the viscosity of the comparative amino composition D (including the total amount of benzyl alcohol) at 25°C.

[0245] (Preparation and Evaluation of Epoxy Resin Compositions)

[0246] In Example 1, except that comparative amino composition D was used instead of amino composition A, the epoxy resin composition was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0247] Comparative Example 2

[0248] The reaction product of styrene and m-xylylenediamine ("Gaskamine 240" manufactured by Mitsubishi Gas Chemical Co., Ltd., AHEW: 103) was used as the comparative amino composition E. The viscosity of the comparative amino composition E at 25°C is shown in Table 2.

[0249] In Example 1, except that comparative amino composition E was used instead of amino composition A, an epoxy resin composition was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0250] Comparative Example 3

[0251] (Production of Comparative Amino Composition F)

[0252] In step (1) of Example 1, the amount of m-xylylenediamine charged was changed to 27.2 g (0.2 mol), the amount of furfural charged was changed to 39.4 g (0.4 mol), and 66.3 g of toluene was added as a solvent. Comparative amino composition F was produced by the same method as in Example 1. The composition of comparative amino composition F is shown in Table 1, and its viscosity and AHEW at 25°C are shown in Table 2.

[0253] (Preparation and Evaluation of Epoxy Resin Compositions)

[0254] In Example 1, except that comparative amino composition F was used instead of amino composition A, an epoxy resin composition was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0255] [Table 1]

[0256]

[0257] [Table 2]

[0258]

[0259] As can be seen from Table 2, the epoxy resin curing agent containing the amino composition of the present invention has a low viscosity, and the coating film of the epoxy resin composition using this curing agent has excellent resistance to aqueous methanol.

[0260] Industrial applicability

[0261] The present invention provides an amino composition having low viscosity and capable of forming a coating film having excellent aqueous methanol resistance when used as an epoxy resin curing agent, a method for producing the same, an epoxy resin curing agent containing the same, an epoxy resin composition, and a cured product thereof.

Claims

1. An amino composition comprising an amino compound (A) represented by the following general formula (1) and an amino compound (B) represented by the following general formula (3), wherein the molar ratio of the amino compound (A) to the amino compound (B) in the composition [(A) / (B)] is 10 / 90 to 99 / 1. NH2-CH2-X-CH2-NH-R 1 (1) Where R 1 is a monovalent group represented by the following general formula (2), X is a phenylene group; In the formula, the dotted line indicates the presence or absence of a π bond, and R 2 ~R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group, and * represents a connecting bond; R 1 -NH-CH2-X-CH2-NH-R 1 (3) Where R 1 and X are the same as above.

2. An epoxy resin curing agent comprising the amino composition according to claim 1.

3. An epoxy resin composition comprising an epoxy resin and the epoxy resin curing agent according to claim 2. A cured product, which is a cured product of the epoxy resin composition according to claim 3.

5. The method for producing an amino composition according to claim 1, comprising the following steps (1) and (2) in sequence: Step (1): a step of reacting a diamine represented by the following general formula (4) with an aldehyde compound represented by the following general formula (5) to obtain an imine, Step (2): a step of reducing the imine obtained in step (1), NH2-CH2-X-CH2-NH2(4) Wherein, X is the same as above; Where R 2 ~R 4 Same as above.

6. The method for producing an amino composition according to claim 5, wherein In the step (1), 0.8 to 1.8 mol of the aldehyde compound represented by the general formula (5) is reacted with 1 mol of the diamine represented by the general formula (4).

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