WO2025239079A1 - Alicyclic diamine and alicyclic-diamine composition - Google Patents

Abstract

Provided is a novel alicyclic diamine which, particularly when used especially as an epoxy resin hardener, can form coating films having excellent water resistance. The alicyclic diamine can be produced from a biomass-derived starting material. Provided are: the alicyclic diamine; an alicyclic-diamine composition including the alicyclic diamine; and an epoxy resin hardener including a product of reaction between an epoxy compound and the alicyclic diamine and the like. The alicyclic diamine is represented by general formula (1) (wherein -CH2NH2 is bonded at a or b).

Description

Alicyclic diamine and alicyclic diamine composition

Related to alicyclic diamines and alicyclic diamine compositions.

Diamines having a cyclic structure made of saturated hydrocarbons (alicyclic diamines) are used as raw materials for synthetic resins, intermediates in organic synthetic chemistry, and curing agents for epoxy resins.
For example, Patent Document 1 lists diaminomethylnorbornane as an example of a raw material for obtaining a novel bisamide compound that serves as a raw material for a resin having good transparency.

Diamine compounds are also known as a type of epoxy resin curing agent. Epoxy resin compositions using diamine compounds as epoxy resin curing agents are used in the coating field, such as anticorrosion coatings for ships, bridges, and land and sea steel structures, and in the civil engineering and construction fields, such as linings, reinforcing, and repair materials for concrete structures, flooring materials for buildings, linings for water supply and sewerage systems, paving materials, and adhesives.
Of these, it is important for epoxy resin compositions for coatings that the resulting coating film has good appearance, water resistance, chemical resistance, coating film properties, etc.
For example, bis(aminomethyl)cyclohexane is fast-curing when used as an epoxy resin curing agent, and the coating film obtained by curing an epoxy resin composition containing this epoxy resin curing agent at room temperature has the characteristic of being excellent in weather resistance.

JP 2011-219539 A

It is known that when bis(aminomethyl)cyclohexane or the like is used as an epoxy resin curing agent, the resulting coating film becomes sticky on the surface due to amine brushing, resulting in a decrease in water resistance. To improve this decrease in water resistance, modified diamines have been used as epoxy resin curing agents. However, modified diamines generally have high viscosity, and further improvements are desired in improving the water resistance of the resulting coating film. High water resistance is also desired in fields other than paints, such as flooring materials and linings, which come into contact with water.
Furthermore, in response to recent environmental issues, biomass-derived resins are being developed, and therefore the raw materials for these resins are also required to be biomass-derived.
Therefore, an object of the present invention is to provide a novel alicyclic diamine that can form a coating film having excellent water resistance, particularly when used as an epoxy resin curing agent, and further to provide an alicyclic diamine that can be produced using raw materials derived from biomass.

The inventors discovered that alicyclic diamines and alicyclic diamine compositions having specific structures can solve the above-mentioned problems, leading to the completion of the present invention.

That is, the present invention is as follows.
[1] An alicyclic diamine represented by the following general formula (1):

(In formula (1), —CH ₂ NH ₂ is bonded to a or b.)
[2] The alicyclic diamine according to [1] above, having a biomass content of 30% by mass or more.
[3] An alicyclic diamine composition containing an alicyclic diamine represented by the following formula (2) and an alicyclic diamine represented by the following formula (3):

[4] The alicyclic diamine composition according to [3] above, having a biomass content of 30% by mass or more.
[5] An epoxy resin curing agent containing at least one selected from the group consisting of the alicyclic diamine according to [1] or [2] above, the alicyclic diamine composition according to [3] or [4] above, a reaction product of an epoxy compound having at least one epoxy group with the alicyclic diamine according to [1] or [2] above, and a reaction product of an epoxy compound having at least one epoxy group with the alicyclic diamine composition according to [3] or [4] above.
[6] The epoxy resin curing agent according to [5], having a biomass content of 30% by mass or more.
[7] A method for producing an alicyclic diamine, comprising hydrogenating a dinitrile represented by the following general formula (4) or a dinitrile represented by the following general formula (5) to obtain an alicyclic diamine represented by the following general formula (1):

(In formulas (4) and (5), —CN bonds to a or b. In formula (1), —CH ₂ NH ₂ bonds to a or b.)
[8] The method for producing an alicyclic diamine according to [7], wherein the alicyclic dinitrile represented by the general formula (4) or the dinitrile represented by the general formula (5) is an alicyclic dinitrile obtained using furfural or furfuryl alcohol as a raw material.

The present invention provides a novel alicyclic diamine that can form a coating film with excellent water resistance, particularly when used as an epoxy resin curing agent. Furthermore, it also provides an alicyclic diamine that can be produced using raw materials derived from biomass.

Hereinafter, in this specification, the expression "XX-YY" means "XX or more and YY or less."

[Alicyclic diamine and alicyclic diamine composition]
The alicyclic diamine of the present invention is an alicyclic diamine represented by the following general formula (1).

(In formula (1), —CH ₂ NH ₂ is bonded to a or b.)

In formula (1), a and b represent the carbon atom of the hydrocarbon ring and the position of that carbon atom.
In formula (1), -CH ₂ NH ₂ is bonded to a or b, but when -CH ₂ NH ₂ is bonded to b, the alicyclic diamine represented by formula (1) is an alicyclic diamine represented by formula (2) below, and when -CH ₂ NH ₂ is bonded to a, the alicyclic diamine represented by formula (1) is an alicyclic diamine represented by formula (3) below. Therefore, the alicyclic diamine represented by formula (1) is an alicyclic diamine represented by formula (2) or an alicyclic diamine represented by formula (3).
The alicyclic diamine represented by formula (2) and the alicyclic diamine represented by formula (3) each include two stereoisomers (exo, endo), and the alicyclic diamine of the present invention may be either one of the stereoisomers or a mixture of the two stereoisomers. The alicyclic diamine represented by formula (2) is 3-((3-(aminomethyl)-7-oxabicyclo[2.2.1]heptan-1-yl)methoxy)propan-1-amine, and the alicyclic diamine represented by formula (3) is 3-((2-(aminomethyl)-7-oxabicyclo[2.2.1]heptan-1-yl)methoxy)propan-1-amine.

The alicyclic diamine of the present invention preferably has a biomass degree of 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and even more preferably 90% by mass or more. There is no upper limit, but it is preferably 100% by mass or less, and even more preferably 100% by mass. As described below, the alicyclic diamine can be obtained using biomass-derived furfural or furfuryl alcohol as a raw material, and the biomass degree can be adjusted to the above range by using biomass-derived raw materials, including these. The biomass degree is the mass proportion of biomass raw materials among the raw materials that contribute to the structure of the resulting alicyclic diamine.

The alicyclic diamine composition of the present invention is an alicyclic diamine composition containing an alicyclic diamine represented by the following formula (2) and an alicyclic diamine represented by the following formula (3): In other words, the alicyclic diamine composition of the present invention can also be said to be a mixture of the alicyclic diamine represented by formula (2) and the alicyclic diamine represented by formula (3), which are the alicyclic diamines.
The alicyclic diamine represented by formula (2) and the alicyclic diamine represented by formula (3) each contain two stereoisomers (exo, endo), and the alicyclic diamine represented by formula (2) and the alicyclic diamine represented by formula (3) contained in the alicyclic diamine composition of the present invention may be either one stereoisomer or a mixture of two stereoisomers. The alicyclic diamine represented by formula (2) is 3-((3-(aminomethyl)-7-oxabicyclo[2.2.1]heptan-1-yl)methoxy)propan-1-amine, and the alicyclic diamine represented by formula (3) is 3-((2-(aminomethyl)-7-oxabicyclo[2.2.1]heptan-1-yl)methoxy)propan-1-amine.

The alicyclic diamine composition of the present invention preferably has a biomass degree of 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and even more preferably 90% by mass or more. There is no upper limit, but it is preferably 100% by mass or less, and even more preferably 100% by mass. As described below, the alicyclic diamine composition can be obtained using biomass-derived furfural or furfuryl alcohol as a raw material, and the biomass degree can be adjusted to fall within the above range by using biomass-derived raw materials, including these. The biomass degree is the mass proportion of biomass raw materials among the raw materials that contribute to the structure of the resulting alicyclic diamine.

In the alicyclic diamine composition of the present invention, the mass ratio [(2)/(3)] of the alicyclic diamine represented by formula (2) to the alicyclic diamine represented by formula (3) is preferably 10/90 to 90/10, more preferably 10/90 to 70/30, even more preferably 20/80 to 50/50, still more preferably 20/80 to 45/55, and even more preferably 25/75 to 40/60.

[Method for producing alicyclic diamine]
Although there is no limitation on the method for producing the alicyclic diamine of the present invention, it is preferable to obtain it by the following production method.
That is, a preferred method for producing an alicyclic diamine is a method for producing an alicyclic diamine, which comprises hydrogenating a dinitrile represented by the following general formula (4) or a dinitrile represented by the following general formula (5) to obtain an alicyclic diamine represented by the following general formula (1):
Generally, the starting material for this production method is either the dinitrile represented by formula (4) alone or the dinitrile represented by formula (5) alone, but a mixture of these may also be used as the starting material.

(In formulas (4) and (5), —CN bonds to a or b. In formula (1), —CH ₂ NH ₂ bonds to a or b.)

<Dinitrile Hydrogenation Process>
This step is a step of hydrogenating a dinitrile represented by formula (4) or a dinitrile represented by formula (5) to obtain an alicyclic diamine represented by the following general formula (1).
The reaction in this step is shown in the following formula:

(In formulas (4) and (5), —CN bonds to a or b. In formula (1), —CH ₂ NH ₂ bonds to a or b.)
The reaction in this step will be explained in more detail below.

In formula (4), a and b represent the carbon atoms and the positions of the carbon atoms in the hydrocarbon ring.
In formula (4), -CN is bonded to a or b, and when -CN is bonded to b, the dinitrile represented by formula (4) is a dinitrile represented by the following formula (4b), and when -CN is bonded to a, the dinitrile represented by formula (4) is a dinitrile represented by the following formula (4a). Therefore, the dinitrile represented by formula (4) is a dinitrile represented by formula (4b) or a dinitrile represented by formula (4a).
The dinitrile represented by formula (4b) and the dinitrile represented by formula (4a) each include two stereoisomers (exo, endo), and the dinitrile may be either one of the stereoisomers or a mixture of the two stereoisomers. The dinitrile represented by formula (4b) is 4-((2-cyanoethoxy)methyl)-7-oxabicyclo[2.2.1]heptane-2-carbonitrile, and the dinitrile represented by formula (4a) is 1-((2-cyanoethoxy)methyl)-7-oxabicyclo[2.2.1]heptane-2-carbonitrile.

As described above, in this step, the dinitrile represented by formula (4b) can be hydrogenated to obtain the alicyclic diamine represented by formula (2), and the dinitrile represented by formula (4a) can be hydrogenated to obtain the alicyclic diamine represented by formula (3).
When obtaining the alicyclic diamine composition containing the alicyclic diamine represented by formula (2) and the alicyclic diamine represented by formula (3), the alicyclic diamine represented by formula (2) and the alicyclic diamine represented by formula (3) may be synthesized separately by the above reaction and then mixed in a desired ratio to obtain the alicyclic diamine composition, or a dinitrile mixture containing the dinitrile represented by formula (4b) and the dinitrile represented by formula (4a) may be used as a raw material to obtain the alicyclic diamine represented by formula (2) and the alicyclic diamine represented by formula (3) by the above reaction. Since the alicyclic diamine composition can be obtained efficiently in a single reaction, it is preferred to use a dinitrile mixture containing the dinitrile represented by formula (4b) and the dinitrile represented by formula (4a) as a raw material to obtain the alicyclic diamine represented by formula (2) and the alicyclic diamine represented by formula (3) by the above reaction.

In formula (5), a and b represent the carbon atoms and the positions of the carbon atoms in the hydrocarbon ring.
In formula (5), -CN is bonded to a or b, and when -CN is bonded to b, the dinitrile represented by formula (5) is a dinitrile represented by the following formula (5b), and when -CN is bonded to a, the dinitrile represented by formula (5) is a dinitrile represented by the following formula (5a). Therefore, the dinitrile represented by formula (5) is a dinitrile represented by formula (5b) or a dinitrile represented by formula (5a).
The dinitrile represented by formula (5b) and the dinitrile represented by formula (5a) each include two stereoisomers (exo, endo), and the dinitrile may be either one of the stereoisomers or a mixture of the two stereoisomers. The dinitrile represented by formula (5b) is 4-((2-cyanoethoxy)methyl)-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitrile, and the dinitrile represented by formula (5a) is 1-((2-cyanoethoxy)methyl)-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitrile.

As described above, in this step, the dinitrile represented by formula (5b) can be hydrogenated to obtain the alicyclic diamine represented by formula (2), and the dinitrile represented by formula (5a) can be hydrogenated to obtain the alicyclic diamine represented by formula (3).
When obtaining the alicyclic diamine composition containing the alicyclic diamine represented by formula (2) and the alicyclic diamine represented by formula (3), the alicyclic diamine represented by formula (2) and the alicyclic diamine represented by formula (3) may be synthesized separately by the above reaction and then mixed in a desired ratio to obtain the alicyclic diamine composition, or a dinitrile mixture containing the dinitrile represented by formula (5b) and the dinitrile represented by formula (5a) may be used as a raw material to obtain the alicyclic diamine represented by formula (2) and the alicyclic diamine represented by formula (3) by the above reaction. Since the alicyclic diamine composition can be obtained efficiently in a single reaction, it is preferred to use a dinitrile mixture containing the dinitrile represented by formula (5b) and the dinitrile represented by formula (5a) as a raw material to obtain the alicyclic diamine represented by formula (2) and the alicyclic diamine represented by formula (3) by the above reaction.

The type of hydrogenation reaction in this step is not particularly limited, and may be any of batch, semi-continuous, continuous, etc.
The reaction temperature of the hydrogenation reaction is preferably 80 to 180°C, more preferably 100 to 140°C from the viewpoint of reaction rate, and even more preferably 110 to 130°C from the viewpoints of selectivity and reaction rate.
The pressure during the hydrogenation reaction is preferably 1 to 20 MPa, more preferably 5 to 10 MPa.
The hydrogenation reaction can be carried out without a solvent, but a solvent may also be used.
Examples of the solvent used in the hydrogenation reaction include water; aromatic compounds such as benzene, o-dichlorobenzene, toluene, and xylene; hydrocarbons such as hexane, heptane, and cyclohexane; alcohols such as methanol, ethanol, isopropyl alcohol, t-butyl alcohol, ethylene glycol, and diethylene glycol; ethers such as dioxane, tetrahydrofuran, dimethoxyethane, and diglyme; and mixtures thereof.
The amount of the solvent used in the hydrogenation reaction is preferably 0 to 30 times by mass, more preferably 0 to 20 times by mass, relative to the amount of the dinitrile represented by formula (4) or the dinitrile represented by formula (5).
The catalyst used in the hydrogenation reaction is not particularly limited as long as it is a catalyst that is commonly used in the hydrogenation of nitrile compounds, but a catalyst containing at least one metal selected from Groups 8 to 11 of the periodic table is preferred.
Specific examples include hydrogenation catalysts containing at least one metal selected from iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, and gold.
The hydrogenation catalyst may be a solid catalyst or a homogeneous catalyst, but a solid catalyst is preferred from the viewpoint of separability from the reactants. Examples of solid catalysts include unsupported metal catalysts and supported metal catalysts.
As the non-supported metal catalyst, sponge metal catalysts such as sponge nickel, sponge cobalt, and sponge copper, or oxides or colloidal catalysts of platinum, palladium, rhodium, ruthenium, and the like are preferred.
Examples of supported metal catalysts include those in which at least one of iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, and gold is supported on a carrier such as magnesia, zirconia, ceria, diatomaceous earth, activated carbon, alumina, silica, zeolite, or titania. Preferred are supported copper catalysts such as copper-chromium catalysts (Adkins catalysts), copper-zinc catalysts, and copper-iron, supported platinum catalysts such as Pt/C and Pt/alumina, supported palladium catalysts such as Pd/C and Pd/alumina, supported ruthenium catalysts such as Ru/C and Ru/alumina, and supported rhodium catalysts such as Rh/C and Rh/alumina.
Among these, a catalyst containing at least one selected from nickel, cobalt and ruthenium is more preferred in terms of reaction activity.
The amount of the hydrogenation catalyst used may be appropriately changed depending on the type of catalyst, but is preferably 0.1 to 100% by mass, more preferably 1 to 20% by mass, based on the total amount of the dinitrile represented by the formula (4) and the dinitrile represented by the formula (5), which are raw materials.
The alicyclic diamine thus obtained is preferably purified by distillation, and the distillation conditions may be appropriately adjusted by adjusting the pressure and temperature during distillation.

<Production method using furfural or furfuryl alcohol as raw material>
A more preferred method for producing an alicyclic diamine is a method for producing an alicyclic diamine in which the dinitrile represented by the general formula (4) or the dinitrile represented by the general formula (5) is a dinitrile obtained using furfural or furfuryl alcohol as a raw material. The dinitrile obtained here can be used as an intermediate raw material and subjected to the hydrogenation step to obtain the target alicyclic diamine. Using furfural or furfuryl alcohol as a raw material is preferred because it can increase the biomass content of the resulting alicyclic diamine.
When the dinitrile to be obtained is the dinitrile represented by formula (4), the present production method is a method for producing an alicyclic diamine in which the dinitrile represented by formula (4) is a dinitrile obtained using furfural or furfuryl alcohol as a raw material.
When the dinitrile to be obtained is the dinitrile represented by formula (5), this production method is a method for producing an alicyclic diamine in which the dinitrile represented by formula (5) is a dinitrile obtained using furfural or furfuryl alcohol as a raw material.
Furthermore, in the case where both the dinitrile represented by the formula (4) and the dinitrile represented by the formula (5) are used as raw materials in the hydrogenation step, it is preferable that the method for producing an alicyclic diamine is one in which both the dinitrile represented by the formula (4) and the dinitrile represented by the formula (5) are dinitriles obtained using furfural or furfuryl alcohol as raw materials.
There is no limitation on the method for obtaining the dinitrile represented by formula (4) or the dinitrile represented by formula (5) from furfural or furfuryl alcohol as a raw material, as long as it is a method that ultimately gives the dinitrile represented by formula (4) or the dinitrile represented by formula (5). Among them, preferred methods are described in detail below.

When furfural, a biomass-derived raw material, is used as the starting material for this production method, it is first hydrogenated to obtain furfuryl alcohol.
Next, as shown in the following formula, a Diels-Alder reaction is carried out using furfuryl alcohol and acrylonitrile to obtain a nitrile represented by the following formula (6) (Diels-Alder reaction step).
Next, as shown in the following formula, the olefin moiety of the nitrile represented by formula (6) is hydrogenated to obtain a nitrile represented by formula (7) below (olefin moiety hydrogenation step).
Next, as shown in the following formula, acrylonitrile is added to the nitrile represented by formula (7) to obtain a dinitrile represented by formula (4) below (acrylonitrile addition step).

(In formula (4), formula (6), and formula (7), —CN is bonded to a or b.)

When furfural, a biomass-derived raw material, is used as the starting material for this production method, it is first hydrogenated to obtain furfuryl alcohol.
Next, as shown in the following formula, a Diels-Alder reaction is carried out using furfuryl alcohol and acrylonitrile to obtain a nitrile represented by the following formula (6) (Diels-Alder reaction step).
Next, as shown in the following formula, acrylonitrile is added to the nitrile represented by formula (6) to obtain an alicyclic nitrile represented by formula (5) below (acrylonitrile addition step).

(In formula (5) and formula (6), —CN is bonded to a or b.)
Next, each of the above steps will be described.

(Diels-Alder reaction step)
In this step, a nitrile represented by formula (6) is obtained by Diels-Alder reaction using furfuryl alcohol and acrylonitrile.
The type of Diels-Alder reaction is not particularly limited, and may be any of batch, semi-continuous, continuous, etc.
The reaction temperature for the Diels-Alder reaction is preferably 20 to 120°C, more preferably 40 to 80°C. The reaction pressure is not particularly limited as long as it allows the reaction to proceed favorably, but is preferably 0 to 5 MPa, more preferably 0 to 1 MPa. The molar ratio of furfuryl alcohol to acrylonitrile (furfuryl alcohol:acrylonitrile) is preferably 1:1 to 1:20, more preferably 1:3 to 1:10.

The Diels-Alder reaction is preferably carried out without a solvent, but a solvent may be used. Examples of solvents that can be used in the Diels-Alder reaction include water; aromatic compounds such as benzene, o-dichlorobenzene, toluene, and xylene; hydrocarbons such as hexane, heptane, and cyclohexane; alcohols such as methanol, ethanol, isopropyl alcohol, t-butyl alcohol, ethylene glycol, and diethylene glycol; ethers such as dioxane, tetrahydrofuran, dimethoxyethane, and diglyme; and mixtures thereof.
The Diels-Alder reaction is preferably carried out without a catalyst, but may be carried out in the presence of a catalyst.
Examples of the catalyst include Lewis acids, silica gel, zeolites, alumina, etc. Specific examples of Lewis acids used as catalysts include ZnCl ₂ , ZnI ₂ , AlCl ₃ , and FeCl ₃ .
The amount of the catalyst is preferably 0.001 to 1 mole, more preferably 0.01 to 0.2 mole, relative to the amount of furfuryl alcohol.

In formula (6), a and b represent the carbon atoms and the positions of the carbon atoms in the hydrocarbon ring.
In formula (6), -CN is bonded to a or b, and when -CN is bonded to b, the nitrile represented by formula (6) is 4-(hydroxymethyl)-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitrile, and when -CN is bonded to a, the nitrile represented by formula (6) is 1-(hydroxymethyl)-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitrile. Each of the nitriles includes two stereoisomers (exo and endo), and the nitrile may be either one of the stereoisomers or a mixture of the two stereoisomers.
Typically, the Diels-Alder reaction produces two types of nitriles, one in which a -CN (cyano group) is bonded to a and the other in which a -CN (cyano group) is bonded to b, as described above. This mixture may be used as a raw material for the next step. Using the mixture ultimately produces an alicyclic diamine composition containing an alicyclic diamine represented by formula (2) and an alicyclic diamine represented by formula (3). When the desired product is an alicyclic diamine composition, it is preferable to use the mixture as a raw material for the next step for simplicity. The two types of nitriles may be separated and used individually as raw materials for the next step, or the ratio of the two types of nitriles may be adjusted and used as a raw material for the next step.

(Hydrogenation step of olefin portion)
In this step, the olefin moiety of the nitrile represented by formula (6) is hydrogenated to obtain a nitrile represented by formula (7).
The type of hydrogenation reaction of the olefin portion is not particularly limited, and any method such as a batch method, a semi-continuous method, or a continuous method may be used.
The reaction temperature of the hydrogenation reaction is preferably 0 to 100° C., more preferably 20 to 60° C. The pressure during the hydrogenation reaction is preferably 0.1 to 20 MPa, more preferably 0.5 to 3 MPa. The hydrogenation reaction can be carried out without a solvent, but a solvent may be used.
Examples of solvents that can be used in the hydrogenation reaction include water; aromatic compounds such as benzene, o-dichlorobenzene, toluene, and xylene; hydrocarbons such as hexane, heptane, and cyclohexane; alcohols such as methanol, ethanol, isopropyl alcohol, t-butyl alcohol, ethylene glycol, and diethylene glycol; ethers such as dioxane, tetrahydrofuran, dimethoxyethane, and diglyme; and mixtures thereof.
The amount of the solvent used in the hydrogenation reaction is preferably 0 to 30 times by mass, more preferably 0 to 20 times by mass, relative to the amount of the nitrile represented by formula (6) which is the raw material in this step.

The catalyst used in the hydrogenation reaction is not particularly limited as long as it is a catalyst commonly used in the hydrogenation of olefins, but a catalyst containing at least one metal selected from Groups 8 to 11 of the periodic table is preferred.
Specific examples include hydrogenation catalysts containing at least one selected from iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum and gold.
The hydrogenation catalyst may be a solid catalyst or a homogeneous catalyst, but a solid catalyst is preferred from the viewpoint of separability from the reactants. Examples of solid catalysts include unsupported metal catalysts and supported metal catalysts.
As the non-supported metal catalyst, sponge metal catalysts such as sponge nickel, sponge cobalt, and sponge copper, or oxides or colloidal catalysts of platinum, palladium, rhodium, ruthenium, and the like are preferred.
Examples of supported metal catalysts include those in which at least one of iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, and gold is supported on a carrier such as magnesia, zirconia, ceria, diatomaceous earth, activated carbon, alumina, silica, zeolite, or titania. Preferred are supported copper catalysts such as copper-chromium catalysts (Adkins catalysts), copper-zinc catalysts, and copper-iron, supported platinum catalysts such as Pt/C and Pt/alumina, supported palladium catalysts such as Pd/C and Pd/alumina, supported ruthenium catalysts such as Ru/C and Ru/alumina, and supported rhodium catalysts such as Rh/C and Rh/alumina.
Among these, a catalyst containing at least one selected from palladium and nickel is more preferred in terms of reaction activity.
The amount of the hydrogenation catalyst used varies depending on the type of catalyst, but is preferably 0.1 to 100% by mass, more preferably 0.1 to 5% by mass, based on the nitrile represented by formula (7) which is the raw material in this step.

In formula (7), a and b represent the carbon atoms and the positions of the carbon atoms in the hydrocarbon ring.
In formula (7), -CN is bonded to a or b, and when -CN is bonded to b, the nitrile represented by formula (7) is 4-(hydroxymethyl)-7-oxabicyclo[2.2.1]heptane-2-carbonitrile, and when -CN is bonded to a, the nitrile represented by formula (7) is 1-(hydroxymethyl)-7-oxabicyclo[2.2.1]heptane-2-carbonitrile. Each of the nitriles includes two stereoisomers (exo and endo), and the nitrile may be either one of the stereoisomers or a mixture of the two stereoisomers.
In addition, when a mixture of two types of nitriles, one in which a -CN (cyano group) is bonded to a and the other in which a -CN (cyano group) is bonded to b, is used as the nitrile represented by formula (6), which is the raw material of this step, a mixture of two types of nitriles represented by formula (7) is obtained in this step, and this mixture may be used as is as the raw material for the next step. By using the mixture, an alicyclic diamine composition containing an alicyclic diamine represented by formula (2) and an alicyclic diamine represented by formula (3) is finally obtained. However, when an alicyclic diamine composition is the target product, it is preferable to use the mixture as the raw material for the next step for simplicity. The two types of nitriles may be separated and used individually as the raw material for the next step, or the ratio of the two types of nitriles may be adjusted and used as the raw material for the next step.

(Acrylonitrile addition step)
In this step, acrylonitrile is added to the nitrile represented by formula (7) or the nitrile represented by formula (6) to obtain the dinitrile represented by formula (4) or the dinitrile represented by formula (5).
The type of acrylonitrile addition reaction is not particularly limited, and may be any of batch, semi-continuous, continuous, etc.
The reaction temperature of the acrylonitrile addition reaction is preferably 0° C. to 100° C., more preferably 10° C. to 40° C. The reaction pressure of the acrylonitrile addition reaction is not limited as long as it allows the reaction to proceed favorably, but is preferably 0 to 5 MPa, more preferably 0 to 1 MPa.
The base catalyst used in the acrylonitrile addition reaction is preferably an inorganic base or an organic base, more preferably an inorganic base.
The inorganic base is preferably at least _one selected from _{the group} consisting of LiOH, NaOH, _KOH , LiHCO3, _NaHO3 , _KHO3 , _Li2CO3 , _Na2CO3 , _K2CO3 , _Cs2CO3 , Mg(OH) ₂ , Ca(OH) ₂ , _Li3PO4 , _Na3PO4 , _K3PO4 , t-BuONa, t- _BuOK , _{and NaH} , and more preferably at least one selected from _the group consisting of NaOH and KOH.
The amount of the base catalyst is preferably 0.01 to 1 mole, more preferably 0.01 to 0.1 mole, relative to the nitrile represented by formula (7) or the nitrile represented by formula (6). The base catalyst can be used in an amount exceeding 1 mole relative to the substrate, but this is not preferred because the amount of base generated as waste increases.
The acrylonitrile addition step may be carried out without a solvent or in the presence of a solvent, such as water, aromatic compounds such as benzene, o-dichlorobenzene, toluene, and xylene; hydrocarbons such as hexane, heptane, and cyclohexane; alcohols such as methanol, ethanol, isopropyl alcohol, t-butyl alcohol, ethylene glycol, and diethylene glycol; ethers such as dioxane, tetrahydrofuran, dimethoxyethane, and diglyme; or mixtures thereof.
The amount of the solvent used in the acrylonitrile addition step is preferably 0 to 30 times by mass, more preferably 0 to 10 times by mass, relative to the nitrile represented by formula (6) which is the raw material in this step.
The amount of acrylonitrile used in the acrylonitrile addition step is expressed as a molar ratio [acrylonitrile/((7) or (6))] relative to the nitrile represented by formula (7) or formula (6), which is the raw material of this step, of preferably 1 to 20, more preferably 1 to 2.

In formula (4), a and b represent the carbon atoms and the positions of the carbon atoms in the hydrocarbon ring.
In formula (4), -CN is bonded to a or b. When -CN is bonded to b, the dinitrile represented by formula (4) is 4-((2-cyanoethoxy)methyl)-7-oxabicyclo[2.2.1]heptane-2-carbonitrile, and when -CN is bonded to a, the nitrile represented by formula (6) is 1-((2-cyanoethoxy)methyl)-7-oxabicyclo[2.2.1]heptane-2-carbonitrile. Each of the nitriles includes two stereoisomers (exo, endo), and the nitrile may be either one of the stereoisomers or a mixture of the two stereoisomers.
In addition, when a mixture of two types of nitriles, one in which a -CN (cyano group) is bonded to a and the other in which a -CN (cyano group) is bonded to b, is used as the nitrile represented by formula (7), which is the raw material of this step, a mixture of two types of dinitriles represented by formula (4) is obtained in this step, and this mixture may be used as is as the raw material for the next step. By using the mixture, an alicyclic diamine composition containing an alicyclic diamine represented by formula (2) and an alicyclic diamine represented by formula (3) is finally obtained. However, when an alicyclic diamine composition is the target product, it is preferable to use the mixture as the raw material for the next step for convenience. The two types of nitriles may be separated and used individually as the raw material for the next step, or the ratio of the two types of nitriles may be adjusted and used as the raw material for the next step.

In formula (5), a and b represent the carbon atoms and the positions of the carbon atoms in the hydrocarbon ring.
In formula (5), -CN is bonded to a or b. When -CN is bonded to b, the dinitrile represented by formula (5) is 4-((2-cyanoethoxy)methyl)-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitrile, and when -CN is bonded to a, the nitrile represented by formula (5) is 1-((2-cyanoethoxy)methyl)-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitrile. Each of the nitriles includes two stereoisomers (exo, endo), and the nitrile may be either one of the stereoisomers or a mixture of the two stereoisomers.
In addition, when a mixture of two types of nitriles, one in which a -CN (cyano group) is bonded to a and the other in which a -CN (cyano group) is bonded to b, is used as the nitrile represented by formula (6), which is the raw material in this step, a mixture of two types of dinitriles represented by formula (5) is obtained in this step, and this mixture may be used as is as the raw material in the next step. By using the mixture, an alicyclic diamine composition containing an alicyclic diamine represented by formula (2) and an alicyclic diamine represented by formula (3) is finally obtained. However, when an alicyclic diamine composition is the target product, it is preferable to use the mixture as the raw material in the next step for convenience. The two types of nitriles may be separated and used individually as the raw material in the next step, or the ratio of the two types of nitriles may be adjusted and used as the raw material in the next step.

<Other methods for producing alicyclic diamines>
In addition to the above-described methods for producing an alicyclic diamine, it is also preferable to produce an alicyclic diamine represented by formula (1) by the following methods. That is, as methods for producing an alicyclic diamine represented by formula (1), the following methods (A) and (B) are also preferable.

(A) An acrylonitrile addition reaction is carried out using furfuryl alcohol and acrylonitrile to obtain an acrylonitrile adduct of furfuryl alcohol. Next, a Diels-Alder reaction is carried out using the adduct and acrylonitrile to obtain a dinitrile represented by formula (5). Next, the olefin moiety is hydrogenated to obtain a dinitrile represented by formula (4). Then, as described above, the dinitrile represented by formula (4) is hydrogenated to obtain an alicyclic diamine represented by formula (1).

(In formula (5) and formula (4), —CN is bonded to a or b.)

(B) An acrylonitrile addition reaction is carried out using furfuryl alcohol and acrylonitrile to obtain an acrylonitrile adduct of furfuryl alcohol. Next, a Diels-Alder reaction is carried out using the adduct and acrylonitrile to obtain a dinitrile represented by formula (5). Then, as described above, an alicyclic diamine represented by formula (1) is obtained.

(In formula (5), —CN is bonded to a or b.)

[Epoxy resin curing agent]
The alicyclic diamine and the alicyclic diamine composition can be suitably used as an epoxy resin curing agent, and when used as an epoxy resin curing agent, the resulting coating film of the epoxy resin composition can have excellent water resistance.
Furthermore, a reaction product obtained by reacting the alicyclic diamine or the alicyclic diamine composition with an epoxy compound can also be suitably used as an epoxy resin curing agent. When used as an epoxy resin curing agent, the resulting coating film of the epoxy resin composition can have excellent water resistance.
Furthermore, modified products obtained by the Mannich reaction of the alicyclic diamine or alicyclic diamine composition with a phenolic compound and an aldehyde compound, modified products obtained by the reaction of the alicyclic diamine or alicyclic diamine composition with a compound having a carboxy group, and modified products obtained by the Michael reaction of the alicyclic diamine or alicyclic diamine composition with an acrylic compound can also be suitably used as epoxy resin curing agents. When used as an epoxy resin curing agent, the resulting coating film of the epoxy resin composition can have excellent water resistance.
Therefore, the epoxy resin curing agent of the present invention is preferably a curing agent selected from the group consisting of the alicyclic diamine, the alicyclic diamine composition, a reaction product of an epoxy compound having at least one epoxy group with the alicyclic diamine, a reaction product of an epoxy compound having at least one epoxy group with the alicyclic diamine composition, a modified product obtained by the Mannich reaction of the alicyclic diamine with a phenolic compound and an aldehyde compound, a modified product obtained by the reaction of the alicyclic diamine with a compound having a carboxy group, a modified product obtained by the Michael reaction of the alicyclic diamine with an acrylic compound, a modified product obtained by the reaction of the alicyclic diamine with a phenolic compound and an aldehyde compound, and a curing agent selected from the group consisting of the alicyclic diamine composition with a phenolic compound and an aldehyde compound. a modified product obtained by a Mannich reaction between the alicyclic diamine composition and a compound having a carboxy group, and a modified product obtained by a Michael reaction between the alicyclic diamine composition and an acrylic compound; and more preferably, an epoxy resin curing agent containing at least one selected from the group consisting of the alicyclic diamine, the alicyclic diamine composition, a reaction product between an epoxy compound having at least one epoxy group and the alicyclic diamine, and a reaction product between an epoxy compound having at least one epoxy group and the alicyclic diamine composition.

The epoxy resin curing agent of the present invention typically contains any one of the following: the alicyclic diamine, the alicyclic diamine composition, a reaction product of the epoxy compound and the alicyclic diamine, a reaction product of the epoxy compound and the alicyclic diamine composition, a modified product obtained by the Mannich reaction of the alicyclic diamine with a phenolic compound and an aldehyde compound, a modified product obtained by the reaction of the alicyclic diamine with a compound having a carboxy group, a modified product obtained by the Michael reaction of the alicyclic diamine with an acrylic compound, a modified product obtained by the Mannich reaction of the alicyclic diamine composition with a phenolic compound and an aldehyde compound, a modified product obtained by the reaction of the alicyclic diamine composition with a compound having a carboxy group, and a modified product obtained by the Michael reaction of the alicyclic diamine composition with an acrylic compound, but may contain two or more of these.

The epoxy resin curing agent of the present invention may further contain a known non-reactive diluent or the like within the range that does not impair the effects of the present invention.
Examples of non-reactive diluents include benzyl alcohol, furfuryl alcohol, tetrafurfuryl alcohol, aromatic hydrocarbon formaldehyde resins, and the like, and one or more of these can be used.
Aromatic hydrocarbon formaldehyde resins are resins obtained by reacting aromatic hydrocarbons with formaldehyde, and examples thereof include toluene formaldehyde resins obtained by reacting toluene with formaldehyde, xylene formaldehyde resins obtained by reacting xylene with formaldehyde, mesitylene formaldehyde resins obtained by reacting mesitylene with formaldehyde, and pseudocumene formaldehyde resins obtained by reacting pseudocumene with formaldehyde.
Commercially available aromatic hydrocarbon formaldehyde resins include, for example, xylene formaldehyde resins manufactured by Fudow Co., Ltd., such as "Nikanol Y-50,""NikanolY-100,""NikanolY-300,""NikanolY-1000,""NikanolL,""NikanolLL,""NikanolLLL,""NikanolG,""NikanolH," and "Nikanol H-80."
Among the above, at least one selected from the group consisting of benzyl alcohol and aromatic hydrocarbon formaldehyde resin is preferred, at least one selected from the group consisting of benzyl alcohol and xylene formaldehyde resin is more preferred, benzyl alcohol is even more preferred, and benzyl alcohol is even more preferred.

The content of the non-reactive diluent is preferably 1 to 99 mass%, more preferably 10 to 90 mass%, even more preferably 20 to 70 mass%, even more preferably 30 to 60 mass%, and even more preferably 35 to 50 mass%, based on the total amount of epoxy resin curing agent.

The total content of the alicyclic diamine, alicyclic diamine composition, reaction product of the epoxy compound and the alicyclic diamine, and reaction product of the epoxy compound and the alicyclic diamine composition used in the epoxy resin curing agent of the present invention is not particularly limited as long as it is 100% by mass or less, but is preferably 1 to 99% by mass, more preferably 10 to 90% by mass, even more preferably 30 to 80% by mass, still more preferably 40 to 70% by mass, and even more preferably 50 to 65% by mass, based on the total amount of the epoxy resin curing agent.

There are no particular limitations on the method for preparing the epoxy resin curing agent of the present invention, and it can be selected appropriately depending on the form of use, the equipment used, the types and blending ratios of the ingredients, etc. For example, it can be prepared by blending and mixing the alicyclic diamine, the alicyclic diamine composition, the reaction product of the epoxy compound and the alicyclic diamine, or the reaction product of the epoxy compound and the alicyclic diamine composition, with other curing agent components, non-reactive diluents, etc., used as needed. Furthermore, the components contained in the epoxy resin curing agent may be mixed with the epoxy resin simultaneously when preparing the epoxy resin composition.

When the epoxy resin curing agent of the present invention contains a reaction product of an epoxy compound having at least one epoxy group with the alicyclic diamine, or a reaction product of an epoxy compound having at least one epoxy group with the alicyclic diamine composition, the "epoxy compound having at least one epoxy group" may be a compound having at least one epoxy group, and more preferably a compound having two or more epoxy groups.
Specific examples of the epoxy compound include epichlorohydrin, butyl diglycidyl ether, neopentyl glycol diglycidyl ether, 1,3-propanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, biphenol diglycidyl ether, dihydroxynaphthalene diglycidyl ether, dihydroxyanthracene diglycidyl ether, triglycidyl isocyanurate, tetraglycidyl glycoluril, a multifunctional epoxy resin having a glycidylamino group derived from metaxylylenediamine, and a glycidylamino group derived from 1,3-bis(aminomethyl)cyclohexane. Examples of the epoxy resin include polyfunctional epoxy resins having a glycidylamino group derived from diaminodiphenylmethane, polyfunctional epoxy resins having a glycidylamino group derived from paraaminophenol, polyfunctional epoxy resins having a glycidyloxy group derived from paraaminophenol, polyfunctional epoxy resins having a glycidyloxy group derived from bisphenol A, polyfunctional epoxy resins having a glycidyloxy group derived from bisphenol F, polyfunctional epoxy resins having a glycidyloxy group derived from phenol novolac, and polyfunctional epoxy resins having two or more glycidyloxy groups derived from resorcinol. These may be used alone or in combination of two or more.
From the viewpoint of forming an epoxy resin cured product having excellent chemical resistance and from the viewpoint of curability, the epoxy compound is more preferably a compound containing an aromatic ring or an alicyclic structure in the molecule, even more preferably a compound containing an aromatic ring in the molecule, and even more preferably a polyfunctional epoxy resin having a glycidyloxy group derived from bisphenol A.

The reaction product of the epoxy compound and the alicyclic diamine or alicyclic diamine composition can be obtained by a ring-opening addition reaction using a known method. For example, a reactor is charged with the alicyclic diamine or alicyclic diamine composition, and the epoxy compound is added all at once or in portions, such as by dropwise addition, and the mixture is heated to allow the reaction to occur. The addition reaction is preferably carried out in an inert atmosphere such as nitrogen gas.

There are no particular restrictions on the amounts of alicyclic diamine or alicyclic diamine composition and epoxy compound used, as long as the ratio is such that the resulting reaction product contains amino groups with active hydrogen. However, from the perspective of ensuring that the resulting reaction product functions as an epoxy resin curing agent, it is preferable to use an excess amount of alicyclic diamine or alicyclic diamine composition relative to the epoxy equivalent of the epoxy compound in the addition reaction. Specifically, the alicyclic diamine or alicyclic diamine composition and epoxy compound are preferably used so that [D]/[G] = 50/1 to 4/1, and more preferably [D]/[G] = 20/1 to 8/1 (where [D] represents the number of active hydrogens in the alicyclic diamine or alicyclic diamine composition, and [G] represents the number of epoxy groups in the epoxy compound).

The temperature and reaction time during the addition reaction can be selected as appropriate, but from the perspective of reaction rate, productivity, and preventing decomposition of raw materials, the temperature during the addition reaction is preferably 50 to 150°C, more preferably 70 to 120°C. The reaction time is preferably 0.5 to 12 hours, more preferably 1 to 6 hours, after the addition of the epoxy compound is complete.

The epoxy resin curing agent of the present invention preferably has a biomass content of 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and even more preferably 90% by mass or more. There is no upper limit, but it is preferably 100% by mass or less, and even more preferably 100% by mass. As mentioned above, the alicyclic diamine and alicyclic diamine composition contained in the epoxy resin curing agent can be obtained using biomass-derived furfural or furfuryl alcohol as raw materials, and the biomass content can be adjusted to the above range by using biomass-derived raw materials, including these. The biomass content is the mass proportion of biomass raw materials among the raw materials that contribute to the structure of the resulting alicyclic diamine.

There are no particular limitations on the method for preparing the epoxy resin curing agent of the present invention, and it can be selected appropriately depending on the form of use, the equipment used, the types and blending ratios of the ingredients, etc. For example, it can be prepared by blending and mixing the alicyclic diamine or alicyclic diamine composition with other curing agent components, non-reactive diluents, etc., which are used as needed. Furthermore, when preparing the epoxy resin composition, the components contained in the epoxy resin curing agent and the epoxy resin may be mixed simultaneously.

The modified product obtained by the Mannich reaction of the alicyclic diamine with a phenolic compound and an aldehyde compound includes the reaction product of the alicyclic diamine with a phenolic compound and an aldehyde compound. Examples of phenolic compounds used in the modification include phenol, cresol, butylphenol, and nonylphenol. Examples of aldehyde compounds include formaldehyde, acetaldehyde, and benzaldehyde, although an aqueous formaldehyde solution is generally used. The reaction ratio of the alicyclic diamine with the phenolic compound and the aldehyde compound during modification is not particularly limited, as long as gelation can be avoided and the resulting reaction product contains an amino group with active hydrogen.

The modified product of the alicyclic diamine and the compound having a carboxy group can be a reaction product of the alicyclic diamine and the compound having a carboxy group. Examples of compounds having a carboxy group used for modification include polymerized fatty acids commonly known as dimer acids, dicarboxylic acids such as adipic acid and sebacic acid, and monocarboxylic acids such as tall oil fatty acids, oleic acid and stearic acid. The reaction ratio of the alicyclic diamine and the compound having a carboxy group during modification is not particularly limited, as long as gelation can be avoided and the resulting reaction product contains an amino group with active hydrogen.

The modified product obtained by the Michael reaction of the alicyclic diamine and acrylic compound can be a reaction product of the alicyclic diamine and a compound having a carbon-carbon double bond adjacent to a nitrile group or a carbonyl group. Specific examples of acrylic compounds used for modification include acrylonitrile and methyl methacrylate. The reaction ratio of the alicyclic diamine and acrylic compound during modification is not particularly limited, as long as gelation can be avoided and the resulting reaction product contains an amino group with active hydrogen.

The modified product obtained by the Mannich reaction of the alicyclic diamine composition with a phenolic compound and an aldehyde compound includes the reaction product of the alicyclic diamine composition with a phenolic compound and an aldehyde compound. Examples of phenolic compounds used in the modification include phenol, cresol, butylphenol, and nonylphenol. Examples of aldehyde compounds include formaldehyde, acetaldehyde, and benzaldehyde, although an aqueous formaldehyde solution is generally used. The reaction ratio of the alicyclic diamine composition with the phenolic compound and aldehyde compound during modification is not particularly limited, as long as gelation can be avoided and the resulting reaction product contains an amino group with active hydrogen.

The modified product of the alicyclic diamine composition and a compound having a carboxy group can be a reaction product of the alicyclic diamine composition and a compound having a carboxy group. Examples of compounds having a carboxy group used for modification include polymerized fatty acids commonly known as dimer acids, dicarboxylic acids such as adipic acid and sebacic acid, and monocarboxylic acids such as tall oil fatty acids, oleic acid, and stearic acid. The reaction ratio of the alicyclic diamine composition and the compound having a carboxy group during modification is not particularly limited, as long as gelation can be avoided and the resulting reaction product contains an amino group with active hydrogen.

The modified product obtained by the Michael reaction of the alicyclic diamine composition with an acrylic compound can be a reaction product of the alicyclic diamine composition with a compound having a carbon-carbon double bond adjacent to a nitrile group or a carbonyl group. Specific examples of acrylic compounds used for modification include acrylonitrile and methyl methacrylate. The reaction ratio of the alicyclic diamine composition and acrylic compound during modification is not particularly limited, as long as gelation can be avoided and the resulting reaction product contains an amino group with active hydrogen.

By mixing the epoxy resin curing agent of the present invention with an epoxy resin, an epoxy resin composition can be obtained, which serves as the raw material for the cured product.

The epoxy resin may be any of a saturated or unsaturated aliphatic compound, an alicyclic compound, an aromatic compound, and a heterocyclic compound. From the viewpoint of obtaining a cured product with a high Tg, an epoxy resin containing an aromatic ring or an alicyclic structure in the molecule is preferred.
Specific examples of the epoxy resin include at least one resin selected from the group consisting of epoxy resins having a glycidylamino group derived from meta-xylylenediamine, epoxy resins having a glycidylamino group derived from para-xylylenediamine, epoxy resins having a glycidylamino group derived from 1,3-bis(aminomethyl)cyclohexane, epoxy resins having a glycidylamino group derived from 1,4-bis(aminomethyl)cyclohexane, epoxy resins having a glycidylamino group derived from diaminodiphenylmethane, epoxy resins having a glycidylamino group and/or a glycidyloxy group derived from para-aminophenol, epoxy resins having a glycidyloxy group derived from bisphenol A, epoxy resins having a glycidyloxy group derived from bisphenol F, epoxy resins having a glycidyloxy group derived from phenol novolac, and epoxy resins having a glycidyloxy group derived from resorcinol. Two or more of the above epoxy resins can also be used in combination.

Among the above, from the viewpoint of obtaining a cured product with a high Tg, the epoxy resin is preferably one having as its main component at least one selected from the group consisting of epoxy resins having a glycidylamino group derived from meta-xylylenediamine, epoxy resins having a glycidylamino group derived from para-xylylenediamine, epoxy resins having a glycidyloxy group derived from bisphenol A, and epoxy resins having a glycidyloxy group derived from bisphenol F, and from the viewpoint of obtaining a cured product with a high Tg, availability, and economy, one having as its main component an epoxy resin having a glycidyloxy group derived from bisphenol A is more preferred.
The term "main component" as used herein means that other components may be contained within a range that does not deviate from the spirit of the present invention, and preferably means 50 to 100% by mass, more preferably 70 to 100% by mass, and even more preferably 90 to 100% by mass of the total.

The content of the epoxy resin curing agent in the epoxy resin composition is such that the ratio of the number of active hydrogens in the epoxy resin curing agent to the number of epoxy groups in the epoxy resin (number of active hydrogens in the epoxy resin curing agent/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.

The epoxy resin composition may further contain other components such as modifying components such as fillers and plasticizers, flow adjusting components such as thixotropic agents, pigments, leveling agents, tackifiers, and elastomer fine particles depending on the intended use.
The total amount of the epoxy resin and the epoxy resin curing agent in the epoxy resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and still more preferably 90% by mass or more, with the upper limit being 100% by mass.

There are no particular restrictions on the method for preparing the epoxy resin composition, and it can be produced by mixing the epoxy resin, epoxy resin curing agent, and, if necessary, other components using known methods and equipment. There are also no particular restrictions on the order in which the components contained in the epoxy resin composition are mixed; the epoxy resin curing agent may be prepared and then mixed with the epoxy resin, or the components that make up the epoxy resin curing agent may be mixed with the epoxy resin simultaneously to prepare the composition.

The epoxy resin composition can be cured by a known method to obtain a cured epoxy resin product. The curing conditions for the epoxy resin composition can be appropriately selected depending on the application and form.
The cured product obtained as described above has excellent water resistance and is therefore particularly suitable for use in coating materials. It can also be used in fields other than coating materials, such as flooring and lining, which come into contact with water. Furthermore, the epoxy resin composition has excellent drying properties, and the resulting cured product has excellent appearance.

[Uses of alicyclic diamine and alicyclic diamine composition]
The alicyclic diamine and the alicyclic diamine composition are novel alicyclic diamines and novel alicyclic diamine compositions, and have excellent solvent solubility, and therefore can be used in a variety of applications. Furthermore, when used as a raw material for a resin, it is believed that the resulting resin can be provided with weather resistance and transparency.
For example, it can be used as a raw material for polyamide, polyimide, polyurethane, polyurea, ligand, etc. Each use will now be described in detail.

<Use as a raw material for polyamide>
The alicyclic diamine and the alicyclic diamine composition are novel alicyclic diamines and novel alicyclic diamine compositions, and are characterized by excellent solvent solubility, and therefore can be suitably used as raw materials for polyamides. Furthermore, the alicyclic diamine and the alicyclic diamine composition are thought to be able to impart weather resistance and transparency to the resulting polyamides.
The polyamide can be obtained by introducing the alicyclic diamine or the diamine containing the alicyclic diamine composition and the dicarboxylic acid into a reaction system and carrying out a polycondensation reaction.
The dicarboxylic acid is not particularly limited, but is preferably at least one selected from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms, terephthalic acid, and isophthalic acid, more preferably an aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and even more preferably an aliphatic dicarboxylic acid having 4 to 12 carbon atoms.
Examples of aliphatic dicarboxylic acids having 4 to 20 carbon atoms include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, and 1,18-octadecanedicarboxylic acid, and among these, at least one selected from adipic acid and sebacic acid is preferably used from the viewpoints of crystallinity and high elasticity. These dicarboxylic acids may be used alone or in combination of two or more.
Examples of other dicarboxylic acids include aliphatic dicarboxylic acids having 3 or less carbon atoms, such as oxalic acid and malonic acid; and aromatic dicarboxylic acids other than terephthalic acid and isophthalic acid, such as 2,6-naphthalenedicarboxylic acid.
The molar ratio of diamine to dicarboxylic acid (diamine/dicarboxylic acid) is preferably in the range of 0.9 to 1.1, more preferably in the range of 0.93 to 1.07, even more preferably in the range of 0.95 to 1.05, and still more preferably in the range of 0.97 to 1.02. When the molar ratio is within the above range, the polymerization of the polymer is facilitated.

<Use as a raw material for polyimide>
The alicyclic diamine and the alicyclic diamine composition are novel alicyclic diamines and novel alicyclic diamine compositions, and are characterized by excellent solvent solubility, and therefore can be suitably used as raw materials for polyimides. Furthermore, the alicyclic diamine and the alicyclic diamine composition are thought to be able to impart weather resistance and transparency to the resulting polyimides.
The polyimide can be obtained by introducing the alicyclic diamine or the diamine containing the alicyclic diamine composition and the tetracarboxylic dianhydride into a reaction system, subjecting the polyamic acid to a ring-opening polyaddition reaction, and then imidizing the polyamic acid. The ring-opening polyaddition reaction and the imidization may be carried out simultaneously.
The tetracarboxylic dianhydride is not particularly limited, but examples thereof include aromatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aliphatic tetracarboxylic dianhydrides.
Examples of aromatic tetracarboxylic dianhydrides include biphenyltetracarboxylic dianhydride (BPDA), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), pyromellitic dianhydride, 3,3',4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, and 2,2',3,3'-benzophenonetetracarboxylic dianhydride.
Examples of alicyclic tetracarboxylic dianhydrides that provide structural units derived from alicyclic tetracarboxylic dianhydrides include 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyltetracarboxylic dianhydride, 5,5'-bis-2-norbornene-5,5',6,6'-tetracarboxylic-5,5',6,6'-dianhydride, and positional isomers thereof.
Examples of aliphatic tetracarboxylic dianhydrides that provide structural units derived from aliphatic tetracarboxylic dianhydrides include 1,2,3,4-butanetetracarboxylic dianhydride, etc. These tetracarboxylic dianhydrides may be used alone or in combination of two or more.

<Use as a raw material for polyurethane>
The alicyclic diamine and the alicyclic diamine composition are novel alicyclic diamines and novel alicyclic diamine compositions, and are characterized by excellent solvent solubility, and therefore can be suitably used as raw materials for polyurethane. Furthermore, the alicyclic diamine and the alicyclic diamine composition are thought to be able to impart weather resistance and transparency to the resulting polyurethane.
The alicyclic diamine and the alicyclic diamine composition are first reacted with phosgene to obtain the corresponding isocyanate, and the obtained isocyanate is reacted with a polyol to obtain a polyurethane.
The polyol is not particularly limited, and examples thereof include polyester polyols, polyether polyols, polycarbonate polyols, and polylactone polyols.
Examples of polyester polyols include condensation polyester polyols such as polyethylene adipate glycol, polybutylene adipate glycol, polyhexamethylene adipate glycol, and polyethylene butylene adipate glycol.
Examples of polyether polyols include aliphatic polyether polyols such as polytetramethylene glycol, polyethylene glycol, and polypropylene glycol.
Examples of polycarbonate polyols include polyols obtained by dealcoholization reaction of low-molecular-weight polyols such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, octanediol, nonanediol, and 1,4-cyclohexanedimethanol with carbonate compounds such as diethylene carbonate, dipropylene carbonate, and diphenyl carbonate.
Examples of polylactone polyols include polylactone diols obtained by ring-opening polymerization of lactone using the above-mentioned low-molecular-weight polyols as initiators, lactone polyester diols such as polycaprolactone diol and polymethylvalerolactone diol.
The polyols can be used alone or in combination of two or more.

<Use as a raw material for polyurea>
The alicyclic diamine and the alicyclic diamine composition are novel alicyclic diamines and novel alicyclic diamine compositions, and are characterized by excellent solvent solubility, and therefore can be suitably used as raw materials for polyureas. Furthermore, the alicyclic diamine and the alicyclic diamine composition are thought to be able to impart weather resistance and transparency to the resulting polyureas.
Polyurea can be obtained by reacting the alicyclic diamine or the alicyclic diamine composition with a polyisocyanate.
The polyisocyanate is not particularly limited as long as it contains a compound having two or more isocyanate groups, and the polyisocyanate is preferably a diisocyanate having two or more isocyanate groups.
Examples of diisocyanates having two isocyanate groups include aliphatic isocyanate compounds such as 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, methylene diisocyanate, isopropylene diisocyanate, lysine diisocyanate methyl ester, and 1,5-octylene diisocyanate; 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI), norbornene diisocyanate, hydrogenated tolylene diisocyanate, methylcyclohexane diisocyanate, and isopropylidene diisocyanate. alicyclic isocyanate compounds such as 4-cyclohexyl isocyanate and dimer acid diisocyanate; and aromatic isocyanate compounds such as 2,4- or 2,6-tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate, p- or m-xylylene diisocyanate (XDI), tolidine diisocyanate, p-phenylene diisocyanate, diphenyl ether diisocyanate, diphenyl sulfone diisocyanate, dianisidine diisocyanate, and tetramethyl-m-xylylene diisocyanate.
Examples of polyisocyanates having three or more isocyanate groups include triphenylmethane triisocyanate, triisocyanate phenylthiophosphate, polymethylene polyphenylene polyisocyanate (polymeric MDI), isocyanurate-modified products and biuret-modified products which are trimers of HDI or TDI.
The polyisocyanates may be used alone or in combination of two or more.

<Use as a ligand>
The alicyclic diamine and the alicyclic diamine composition are novel alicyclic diamines and novel alicyclic diamine compositions, and are characterized by excellent solvent solubility, and therefore can be suitably used as ligands. It is believed that the use of the alicyclic diamine and the alicyclic diamine composition as ligands can be used for metal catalysts, etc., and also that they can be used as chelating agents for removing or separating metal ions.
The metals used as the metal ions are preferably elements of Groups 3 to 11, more preferably transition metals, and even more preferably noble metals.

<Other uses>
The alicyclic diamine and alicyclic diamine composition of the present invention, and the polyamide resins, polyimide resins, polyurethane resins, polyurea resins, and the like using the alicyclic diamine or alicyclic diamine composition of the present invention can be used in a variety of applications, including various molded articles, various housings, paints, adhesives, composite materials, insulating materials, sealants, molding powders, liners, various coatings, water treatment agents, fiber treatment agents, dispersants, surfactants, bleaching agents, corrosion inhibitors, paper strength agents, connectors, _CO2 absorbents, dielectric materials, various films, electronic substrate materials, fiber materials, switches, and the like.
However, the uses of the alicyclic diamine and the alicyclic diamine composition of the present invention are not limited to the above uses.

The present invention will be described in detail below using examples and comparative examples, but the present invention is not limited to the following examples. The alicyclic diamine composition was analyzed and evaluated using the following methods.

<Gas chromatography>
Equipment used: Gas chromatograph 8860GC (Agilent Technologies)
Column: DB-1 (length 30 m, inner diameter 530 μm, film thickness 1.5 μm)
Detector: FID (H ₂ 40 mL/min, Air 450 mL/min)
Carrier gas: He
Split ratio: 5:1
Inlet temperature: 250℃
Detector temperature: 250°C
Injection volume: 1.0μL
Oven temperature: After maintaining at 60°C for 6 minutes, the temperature was increased from 60°C to 280°C at a rate of 7°C/min, and after reaching 280°C, it was maintained for 20 minutes.

<GC-MS>
(GC side)
Equipment used: Gas chromatograph GC2010 Plus (Shimadzu Corporation)
Column: DB-1MS (length 30 m, inner diameter 0.25 mm, film thickness 0.25 μm)
Carrier gas: He
Split ratio: 5:1
Vaporization chamber temperature: 250°C
Injection volume: 1μL
Oven temperature: After maintaining at 60°C for 6 minutes, the temperature was increased from 60°C to 280°C at a rate of 7°C/min, and after reaching 280°C, it was maintained for 20 minutes.
(MS side)
Equipment used: GCMS-QP2010 Ultra (Shimadzu Corporation)
Fragmentation method: EI
Ion source temperature: 200°C
Interface temperature: 250°C

<Measurement of total amine value>
The total amine value of the alicyclic diamine composition was measured by potentiometric titration in accordance with JIS-K-7237:1995 using an automatic potentiometric titrator "AT-710S" manufactured by Kyoto Electronics Manufacturing Co., Ltd. However, the sample solvent was changed from the o-nitrotoluene/acetic acid solution specified in JIS to acetic acid.

<Measurement of active hydrogen equivalent weight (AHEW)>
The AHEW of the alicyclic diamine composition and the epoxy resin curing agent was calculated from the total amine value determined using an automatic potentiometric titrator "AT-710S" manufactured by Kyoto Electronics Manufacturing Co., Ltd. The total amine value was measured using a 0.1 mol/L perchloric acid/acetic acid solution (manufactured by Kanto Chemical Co., Inc.).

The structure of each component contained in the alicyclic diamine composition obtained in the examples was identified by NMR analysis under the following conditions.
(NMR analysis)
Equipment used: AVANCE NEO 400 NMR spectrometer manufactured by Bruker Japan Co., Ltd. Resonance frequency: 400 MHz
Mode: Proton ( ¹ H), Carbon ( ¹³ C), HSQC ( ¹ H- ¹³ C)
Measurement temperature: room temperature Solvent: CDCl ₃ (deuterated chloroform)
Chemical shift reference substance: tetramethylsilane

<Evaluation of dryness (dry to the touch)>
A zinc phosphate-treated steel plate (SPCC-SD PB-N144, 0.8 mm x 70 mm x 150 mm, manufactured by Paltec Co., Ltd.) was used as the substrate. The epoxy resin composition was applied to the substrate using an applicator at 23°C and 50% RH to form a coating film (coating film thickness immediately after application: 200 μm). This coating film was stored at 23°C and 50% RH, and evaluated by touch after 1 day and 7 days according to the following criteria.
Ex: Excellent (the coating film is not sticky even when pressed with a thumb with a force of approximately 50 N, and no fingerprints remain)
G: Good (the coating film is not sticky when pressed with a thumb with a force of about 50 N, but fingerprints remain after touching)
F: Fair (the coating is sticky when pressed with a thumb with a force of about 50 N)
P: Poor (the coating film is sticky when pressed with a thumb with a force of about 5 N)

<Water resistance evaluation (water resistance spot test)>
The epoxy resin composition was applied to a substrate (zinc phosphate-treated steel plate) in the same manner as above to form a coating film (thickness immediately after application: 200 μm). This coating film was stored under conditions of 23°C and 50% RH, and after 1 day and 7 days, 2 to 3 drops of pure water were applied to the coating surface using a dropper, and the applied area was then capped with a 50 mL screw cap bottle. 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 1.
Ex: Excellent (no change in appearance)
G: Good (no cloudiness or surface roughness, but gloss reduction observed)
F: Fair (slightly cloudy or rough surface)
P: Poor (significant cloudiness or surface roughness)

<Appearance>
The epoxy resin composition was applied to a substrate (zinc phosphate-treated steel plate) in the same manner as above to form a coating film (thickness immediately after application: 200 μm). The appearance of the resulting coating film was visually observed after one day, and the transparency and gloss were evaluated according to the following criteria.
(transparency)
Ex: Excellent (no cloudiness)
G: Good (slight cloudiness, but no problems in use)
F: Fair (slightly cloudy)
P: Poor (cloudy)
(Gloss)
Ex: Excellent (glossy)
G: Good (slightly less glossy, but no problems in use)
F: Fair (low gloss)
P: Poor (no gloss)

Example 1
(Production of alicyclic diamine composition)
(1) Diels-Alder reaction step

(In formula (6), —CN is bonded to a or b.)
A 1000 mL two-neck flask equipped with a condenser was charged with 150 g (1.53 mol) of furfuryl alcohol and 405 g (7.63 mol) of acrylonitrile, and the mixture was heated to 60°C in an oil bath under a nitrogen atmosphere and stirred to form a homogeneous solution. The reaction was carried out at 60°C for 48 hours with stirring.
After cooling, the acrylonitrile was removed using an evaporator to obtain 210 g of a concentrated liquid containing a nitrile composition represented by the formula (6) (containing a nitrile in which —CN is bonded to a and a nitrile in which —CN is bonded to b).

(2) Hydrogenation of the olefin portion

(In formula (6), —CN is bonded to a or b. In formula (7), —CN is bonded to a or b.)
Next, 210 g of the concentrated liquid, 1.2 g of a 5 mass % Pd/C catalyst (water content: 56.7%, dry mass: 0.52 g), and 27 g of ethyl acetate were charged into a 500 mL autoclave, and after replacing the atmosphere inside the reactor with nitrogen and hydrogen, hydrogen was introduced so that the hydrogen pressure became 2.0 MPa. The reaction was carried out at a reaction temperature of 60°C for 2 hours while stirring.
Thereafter, the mixture was cooled, and furfuryl alcohol and ethyl acetate were removed by simple distillation to obtain 160 g of a concentrated liquid containing a nitrile composition represented by the formula (7) (containing a nitrile in which —CN is bonded to a and a nitrile in which —CN is bonded to b).

(3) Acrylonitrile addition step

(In formula (7), —CN bonds to a or b. In formula (4), —CN bonds to a or b.)
Next, 160 g of the concentrate, 160 g of tetrahydrofuran, 4.5 g of a 50% by mass aqueous solution of sodium hydroxide, and 77 g of acrylonitrile were charged into a 1000 mL two-neck flask equipped with a condenser, heated to 25°C using a water bath, and stirred to obtain a homogeneous solution. The reaction was carried out for 6 hours at a reaction temperature of 25°C while stirring. After completion of the reaction, the mixture was neutralized with 1 mol/L hydrochloric acid, and the tetrahydrofuran was removed using an evaporator. Thereafter, 100 mL of water was added, and the mixture was extracted with a mixture of ethyl acetate and methanol (127 mL/5 mL). The extract was washed with a saturated aqueous solution of sodium carbonate, dehydrated with magnesium sulfate, and the solvent was removed using an evaporator to obtain 180 g of a concentrate containing a dinitrile composition represented by formula (4) (including a dinitrile in which -CN is bonded to a and a dinitrile in which -CN is bonded to b).

(4) Hydrogenation of dinitrile

(In formula (4), —CN bonds to a or b. In formula (1), —CH ₂ NH ₂ bonds to a or b.)
Next, 150 g of the concentrate containing the dinitrile composition represented by formula (4), 15 g (water content: 40.0%, dry mass: 9 g) of a sponge cobalt catalyst (RANEY2724, manufactured by W.R. Grace) and 150 g of tetrahydrofuran were charged into a 500 mL autoclave, and after the atmosphere inside the reactor was replaced with nitrogen and hydrogen, hydrogen was introduced so that the hydrogen pressure became 8.0 MPa, and the reaction was carried out at a reaction temperature of 120°C for 2 hours with stirring.
After cooling, the resulting reaction mixture was filtered to remove the sponge cobalt catalyst, and tetrahydrofuran was removed from the filtrate using an evaporator, yielding 150 g of a concentrated liquid. The concentrated liquid was subjected to simple distillation to obtain an alicyclic diamine composition represented by formula (1). The total purity of 3-((3-(aminomethyl)-7-oxabicyclo[2.2.1]heptan-1-yl)methoxy)propan-1-amine (alicyclic diamine represented by formula (2)) and 3-((2-(aminomethyl)-7-oxabicyclo[2.2.1]heptan-1-yl)methoxy)propan-1-amine (alicyclic diamine represented by formula (3)) was 99.9% based on the peak area in gas chromatography.
In the obtained alicyclic diamine composition, the molar ratio ((2)/(3)) of the alicyclic diamine represented by formula (2) to the alicyclic diamine represented by formula (3) was 35/65. The total amine value of the alicyclic diamine composition was 522 mg KOH/g. The theoretical value of the total amine value was 523.6 mg KOH/g, which was almost the same. The AHEW of the alicyclic diamine composition was 54 g/equivalent.

The results of NMR analysis of the obtained alicyclic diamine composition are shown below. HSQC ( ¹ H- ¹³ C) was used to confirm whether each peak observed in the ¹ H-NMR spectrum was a proton signal derived from a hydrogen atom bonded to a carbon or a proton signal derived from a hydrogen atom bonded to a nitrogen, and to confirm which carbon atom each peak observed in the ¹³ C-NMR spectrum was a signal derived from.

¹ H-NMR chemical shift: δ: 1.12 (s, 4H, [b]), 0.97-2.29 (m, 9H, [a]), 1.85-2.85 (m, 4H, [c]), 3.54-3.80 (m, 4H, [d]), 4.33-4.52 (m, 1H, [e])

^C -NMR chemical shifts: δ: 24.97, 26.40, 30.51, 30.95, 31.26, 31.28, 32.03, 33.30, 33.53, 33.57, 36.85, 36.94, 37.07, 37.42, 39.60, 39.62, 39.63, 39.69, 44.17 , 44.31, 44.61, 45.97, 46.29, 47.74, 47.77, 69.84, 69.91, 70.01, 70.71, 71.75, 71.85, 72.01, 76.44, 76.65, 78.94, 79.00, 85.91, 85.98, 86.37, 87.44
24.97 to 37.42 are derived from carbon atoms of [A]. 39.60 to 44.61 are derived from carbon atoms of [B]. 45.97 to 47.77 are derived from carbon atoms of [C]. 69.84 to 72.01 are derived from carbon atoms of [D]. 76.44 to 79.00 are derived from carbon atoms of [E]. 85.91 to 87.44 are derived from carbon atoms of [F].

Furthermore, GC-MS analysis of the obtained alicyclic diamine composition showed a molecular weight of 214, compared to the molecular weight of each alicyclic diamine constituting the alicyclic diamine composition, which was 214.

Example 2
(Preparation of epoxy resin curing agent)
The alicyclic diamine composition was diluted with benzyl alcohol, a non-reactive diluent, in an amount of 40 mass % of the total, to obtain an epoxy resin curing agent with a concentration of the alicyclic diamine composition of 60 mass %. The active hydrogen equivalent (AHEW) derived from amino groups of the epoxy resin curing agent (total amount including benzyl alcohol) was 90 g/equivalent.

(Preparation and Evaluation of Epoxy Resin Compositions)
As the epoxy resin, which is the main component, a liquid epoxy resin having a glycidyloxy group derived from bisphenol A ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight 186 g/equivalent) was used.
The epoxy resin and the epoxy resin curing agent were blended in the amounts shown in Table 1 and stirred and mixed at 23°C to prepare epoxy resin compositions. The ratio of the number of active hydrogens in the epoxy resin curing agent to the number of epoxy groups in the main epoxy resin (number of active hydrogens in the epoxy resin curing agent/number of epoxy groups in the main epoxy resin) was set to 1/1.
The epoxy resin compositions thus obtained were evaluated for drying property, water resistance and appearance by the methods described above. The results are shown in Table 1.

Comparative Examples 1 and 2
(Preparation and Evaluation of Epoxy Resin Compositions)
Epoxy resin compositions were prepared and evaluated in the same manner as in Example 1, except that 1,3-BAC (1,3-bis(aminomethyl)cyclohexane) and IPDA (isophoronediamine) were used instead of the alicyclic diamine composition in Example 1. The results are shown in Table 1.

Example 3
(Preparation of epoxy resin curing agent)
A 300 mL separable flask equipped with a stirrer, thermometer, nitrogen inlet tube, dropping funnel, and condenser was charged with 29 g of the alicyclic diamine composition obtained in Example 1. Under a nitrogen stream, 10 g of a multifunctional epoxy resin having glycidyloxy groups derived from bisphenol A ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 186 g/equivalent) was added dropwise over 2 hours (an amount such that the number of active hydrogens in the alicyclic diamine composition/the number of epoxy groups in the epoxy compound = 10/1). After the addition was completed, the temperature was raised to 80°C and the reaction was continued for 2 hours, yielding a reaction product of the epoxy compound and the alicyclic diamine composition. The mixture was diluted with benzyl alcohol, a non-reactive diluent, to 40% by mass of the total amount, yielding an epoxy resin curing agent with a concentration of 60% by mass. The active hydrogen equivalent weight (AHEW) of the epoxy resin curing agent (total amount including benzyl alcohol) was 134 g/equivalent.

(Preparation and Evaluation of Epoxy Resin Compositions)
As the epoxy resin, which is the main component, a liquid epoxy resin having a glycidyloxy group derived from bisphenol A ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight 186 g/equivalent) was used.
Epoxy resins and epoxy resin curing agents were blended in the amounts shown in Table 1 and stirred and mixed at 23°C to prepare epoxy resin compositions. The ratio of the number of active hydrogens in the epoxy resin curing agent to the number of epoxy groups in the main epoxy resin (number of active hydrogens in the epoxy resin curing agent/number of epoxy groups in the main epoxy resin) was adjusted to 1/1.
The epoxy resin compositions thus obtained were evaluated for drying property, water resistance and appearance by the methods described above. The results are shown in Table 1.

Comparative Examples 3 and 4
(Preparation and Evaluation of Epoxy Resin Compositions)
Epoxy resin compositions were prepared and evaluated in the same manner as in Example 3, except that 1,3-BAC (1,3-bis(aminomethyl)cyclohexane) and IPDA (isophoronediamine) were used instead of the alicyclic diamine composition in Example 3. The results are shown in Table 1.

From Table 1, it can be seen that the coating film of the epoxy resin composition using the epoxy resin curing agent containing the alicyclic diamine of the present invention has excellent water resistance. Furthermore, it can be seen that the epoxy resin composition using the epoxy resin curing agent containing the alicyclic diamine of the present invention has excellent drying properties, and the obtained cured product also has excellent appearance. It can be seen that the alicyclic diamine and alicyclic diamine composition of the present invention are particularly useful as epoxy resin curing agents.
Therefore, the alicyclic diamine and alicyclic diamine composition of the present invention, and the epoxy resin curing agent and epoxy resin composition using them can be suitably used in coating applications. Furthermore, they can be suitably used in fields other than coating applications, such as flooring materials and linings, which come into contact with water.

Claims (8)

Alicyclic diamines represented by the following general formula (1):

(In formula (1), —CH ₂ NH ₂ is bonded to a or b.) The alicyclic diamine according to claim 1, having a biomass content of 30% by mass or more. An alicyclic diamine composition containing an alicyclic diamine represented by the following formula (2) and an alicyclic diamine represented by the following formula (3):
The alicyclic diamine composition according to claim 3, having a biomass content of 30% by mass or more. An epoxy resin curing agent containing at least one member selected from the group consisting of the alicyclic diamine according to claim 1 or 2, the alicyclic diamine composition according to claim 3 or 4, a reaction product of an epoxy compound having at least one epoxy group with the alicyclic diamine according to claim 1 or 2, and a reaction product of an epoxy compound having at least one epoxy group with the alicyclic diamine composition according to claim 3 or 4. The epoxy resin curing agent according to claim 5, having a biomass content of 30% by mass or more. A method for producing an alicyclic diamine, comprising hydrogenating a dinitrile represented by the following general formula (4) or a dinitrile represented by the following general formula (5) to obtain an alicyclic diamine represented by the following general formula (1):

(In formulas (4) and (5), —CN bonds to a or b. In formula (1), —CH ₂ NH ₂ bonds to a or b.) 8. The method for producing an alicyclic diamine according to claim 7, wherein the dinitrile represented by the general formula (4) or the dinitrile represented by the general formula (5) is a dinitrile obtained using furfural or furfuryl alcohol as a raw material.