JPWO2017179359A1 - Epoxy resin curing agent, epoxy resin composition, carbon fiber reinforced composite material - Google Patents

Abstract

The compound (B) having at least one epoxy group in the molecule was reacted at a ratio of more than 0.100 mol and less than 0.200 mol with respect to 1 mol of the amine compound (A) represented by the following general formula (1). An epoxy resin curing agent containing an addition reaction product, an epoxy resin composition containing the same, and a carbon fiber reinforced composite material containing a cured product of the epoxy resin composition and carbon fibers.
_{H 2 N-H 2 C-} A-CH 2 -NH 2 (1)
(In Formula (1), A is a cyclohexylene group or a phenylene group.)

Description

  The present invention relates to an epoxy resin curing agent, an epoxy resin composition containing the epoxy resin curing agent and an epoxy resin, a cured product of the epoxy resin composition, and a carbon fiber reinforced composite material including carbon fibers.

  Carbon fiber reinforced composite materials (hereinafter also referred to as “CFRP (Carbon Fiber Reinforced Plastics)”) are attracting attention as metal substitute materials because of their extremely high elastic modulus, strength, and light weight. Demand for CFRP is expected to accelerate especially for automotive structural materials, wind power blade applications, pressure vessel applications, and aerospace applications. There is also a demand for carbon fibers used in CFRP and matrix resins such as epoxy resins. It has increased in recent years.

By the way, since the CFRP molding methods are different for automobile structural material applications, wind power generation blade applications, pressure vessel applications, and aerospace applications, the required characteristics for the matrix resin for CFRP also differ depending on the applications.
For example, wind power blades have been molded by infusion molding, Va-RTM method (Vacuum Assist Resin Transfer Molding) or Light-RTM method. In these methods, for example, reinforcing fibers are arranged in advance in a mold composed of an upper mold using a film or FRP and a lower mold, and the mold is evacuated to obtain an epoxy resin composition serving as a matrix resin. It is filled with normal pressure and impregnated into reinforcing fibers, and then the epoxy resin is cured and molded.
In molding by infusion molding, Va-RTM method, and Light-RTM method, it is usual to fill the mold with an epoxy resin composition in which an epoxy resin and an epoxy resin curing agent are mixed due to the characteristics of the molding method. Takes tens of minutes. Therefore, the epoxy resin composition used in these molding methods is required to have a low viscosity and a long pot life. As an epoxy resin curing agent, isophorone diamine, a polyamine compound having a polyether skeleton, and the like are used.

  In CFRP for pressure vessels, molding by the filament winding method is used. The filament winding method is a method in which the outer surface of a liner is coated with a reinforcing fiber yarn obtained by impregnating a reinforcing fiber yarn with a matrix resin such as an epoxy resin composition, and then the matrix resin is cured. When the epoxy resin composition used in this method has a short pot life and is fast curable, the epoxy resin is cured at a stage before molding. Therefore, a fast-curing epoxy resin composition cannot be applied to the filament winding method.

On the other hand, CFRP for automotive structural materials is molded by the high cycle RTM method. This is an improvement over the conventional RTM method.
The conventional RTM method is one of sealed molds using a pair of upper and lower molds. A fiber reinforced preform is placed in the mold, the mold is clamped and sealed, and then epoxy resin is injected from the injection hole. In this method, a resin such as a composition is poured into a mold and impregnated into a fiber reinforced preform, and then the resin is cured and then released. However, the conventional RTM method requires several hours for molding time (preform placement, resin impregnation, resin curing, and mold release). Therefore, in the production of CFRP for automotive structural materials, higher productivity and higher cycle The RTM method is used.

  The molding technology based on the high cycle RTM method has greatly reduced all of the fiber reinforced preform placement time, resin impregnation time, resin curing time, and mold release time, and has shortened the total molding time to about 10 minutes. Is. In the high cycle RTM method, in the process from resin impregnation to curing, for example, in the high pressure RTM method, which is a kind of high cycle RTM method, the reinforcing fibers are arranged in a pair of upper and lower molds and sealed, and the inside of the mold is sealed. Apply vacuum. Next, the epoxy resin that is the main component of the epoxy resin composition and the epoxy resin curing agent are pumped in a mist state from separate tanks to the mixing head, and after impingement mixing, they are immediately injected into the mold and impregnated into carbon fibers. And cure the epoxy resin. The epoxy resin composition after the impingement mixing is injected at a high pressure from a plurality of injection holes in order to increase the filling speed into the mold and the impregnation speed into the carbon fiber.

  In the high cycle RTM method, since the epoxy resin and the epoxy resin curing agent are mixed and immediately injected into the mold, the pot life of the epoxy resin composition, which is a mixture of the epoxy resin and the epoxy resin curing agent, is required so much. And not. On the other hand, from the viewpoint of productivity, it is required that the impregnation into the reinforcing fiber, the filling rate into the mold is high, and the curing is fast, so that the epoxy resin composition used in the high cycle RTM method has a low It must be viscous and fast-curing.

  It is known to use a polyamine compound or a modified product thereof as an epoxy resin curing agent. For example, Patent Documents 1 to 3 disclose an epoxy resin curing agent containing a modified product of a polyamine compound such as bis (aminomethyl) cyclohexane or xylylenediamine.

JP-A-8-3282 JP 2001-163955 A JP 2007-186893 A

  In an epoxy resin curing agent used for molding by a high cycle RTM method and the like and an epoxy resin composition containing the curing agent and an epoxy resin, it is necessary to achieve both fast curability and low viscosity. However, when applied to the above molding method, conventional epoxy resin curing agents and epoxy resin compositions have not been satisfactory in achieving both fast curability and low viscosity. In order to improve the fast curability, for example, a method of adding a large amount of a curing accelerator is also conceivable. However, in this case, the pot life of the epoxy resin composition is shortened, which may not be suitable for molding a large member.

  An object of the present invention is an epoxy resin curing agent and an epoxy resin composition, which are fast-curing and low-viscosity, and are suitably used for molding by a high cycle RTM method, etc., and a cured product and carbon of the epoxy resin composition It is providing the carbon fiber reinforced composite material containing a fiber.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by an epoxy resin curing agent containing an addition reaction product of an amine compound having a specific structure and a predetermined amount of an epoxy compound. .

That is, the present invention relates to the following [1] to [13].
[1] With respect to 1 mol of the amine compound (A) represented by the following general formula (1), the compound (B) having at least one epoxy group in the molecule is more than 0.100 mol and less than 0.200 mol. An epoxy resin curing agent containing a reacted addition reaction product.
_{H 2 N-H 2 C-} A-CH 2 -NH 2 (1)
(In Formula (1), A is a cyclohexylene group or a phenylene group.)
[2] The epoxy resin curing agent according to the above [1], wherein in the general formula (1), A is a cyclohexylene group.
[3] The epoxy resin curing agent according to the above [1] or [2], wherein the compound (B) is a diglycidyl ether compound having an aromatic ring in the molecule.
[4] The epoxy resin curing agent according to [3], wherein the compound (B) is a compound represented by the following general formula (2).

(In formula (2), R ^{11 to} R ¹⁴ are each independently an alkyl group having 1 to 6 carbon atoms, and a, b, c, and d are each independently an integer of 0 to 4. Multiple R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ may be the same or different from each other, X ¹ and X ² are each independently a single bond, —CH ₂ —, —CH (CH ₃ )-, or -C (CH ₃ ) _2- , R ¹⁵ is -CH ₂ CH (OH)-, or -CH (OH) CH _2- , n represents the average number of repeating units, and 0 A number of ~ 1.0.)
[5] The epoxy resin curing agent according to any one of [1] to [4], further including a curing accelerator.
[6] An epoxy resin composition containing the epoxy resin curing agent according to any one of [1] to [5] above and an epoxy resin.
[7] The epoxy resin composition according to [6], wherein the epoxy resin is an epoxy resin containing an aromatic ring or an alicyclic structure in the molecule.
[8] The epoxy resin composition according to the above [7], wherein the epoxy resin is an epoxy resin represented by the following general formula (4).

(In formula (4), R ^{21 to} R ²⁴ are each independently an alkyl group having 1 to 6 carbon atoms, and p, q, r, and s are each independently an integer of 0 to 4. ²¹ , the plurality of R ²² , the plurality of R ²³ , and the plurality of R ²⁴ may all be the same or different from each other, Y ¹ and Y ² are each independently a single bond, —CH ₂ —, —CH ( CH ₃ ) —, or —C (CH ₃ ) ₂ —, R ²⁵ is —CH ₂ CH (OH) —, or —CH (OH) CH ₂ —, m represents the average number of repeating units, It is a number from 0 to 0.2.)
[9] The epoxy resin composition according to any one of [6] to [8], wherein a viscosity at a temperature of 40 ° C. is 5,000 mPa · s or less.
[10] The epoxy resin composition according to any one of [6] to [9], which is for a carbon fiber reinforced composite material.
[11] A carbon fiber reinforced composite material comprising a cured product of the epoxy resin composition according to any one of [6] to [10] above and carbon fiber.
[12] The carbon fiber reinforced composite material according to [11], which is a structural material for automobiles.
[13] A step of forming by a low pressure RTM method, a medium pressure RTM method, a high pressure RTM method, a compression RTM method, a liquid compression molding method, a liquid laydown method, a spray laydown method, a surface RTM method, a prepreg compression molding method or a liquid cast molding method. The method for producing a carbon fiber reinforced composite material according to the above [11] or [12].

  According to the present invention, it is possible to provide an epoxy resin curing agent and an epoxy resin composition that are fast-curing and low-viscosity capable of producing CFRP such as automobile structural materials and building materials with high productivity by a high cycle RTM method or the like. it can. When the epoxy resin composition is used as a CFRP matrix resin, it has excellent carbon fiber impregnation properties and is fast-curing, so that it takes only a short time to release from the mold, and CFRP production. Can be improved.

[Epoxy resin curing agent]
In the epoxy resin curing agent of the present invention, the amount of the compound (B) having at least one epoxy group in the molecule exceeds 0.100 mol per mol of the amine compound (A) represented by the following general formula (1). It is characterized by containing an addition reaction product reacted at a ratio of less than 200 mol.
_{H 2 N-H 2 C-} A-CH 2 -NH 2 (1)
(In Formula (1), A is a cyclohexylene group or a phenylene group.)
By making the amine compound (A) an addition reaction product modified by the addition reaction with the compound (B), curability when used as an epoxy resin curing agent can be improved. On the other hand, when the amine compound (A) is modified with the compound (B), the viscosity tends to be improved. Therefore, in the present invention, an epoxy resin curing agent and an epoxy resin composition that achieve both fast curability and low viscosity are obtained by setting the addition amount of the compound (B) to the amine compound (A) within the predetermined range. It is a thing.

(Amine compound (A))
The amine compound (A) is a compound represented by the general formula (1). In Formula (1), A is a cyclohexylene group or a phenylene group, and a cyclohexylene group is preferable. Specifically, A is 1,2-cyclohexylene group, 1,3-cyclohexylene group, 1,4-cyclohexylene group, 1,2-phenylene group, 1,3-phenylene group, and 1,4-cyclohexyl group. One or more selected from the group consisting of phenylene groups, from the viewpoint of heat resistance and weather resistance, and cured physical properties of the resulting epoxy resin composition, 1,2-cyclohexylene group, 1,3-cyclohexylene group, and One or more selected from the group consisting of 1,4-cyclohexylene groups are preferred, and 1,3-cyclohexylene groups are more preferred. The cyclohexylene group in this specification includes both cis and trans forms.

Specific examples of the amine compound (A) include 1,2-bis (aminomethyl) cyclohexane, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, o-xylylenediamine, Examples include m-xylylenediamine (MXDA) and p-xylylenediamine (PXDA).
Among the above, as the amine compound (A), 1,2-bis (aminomethyl) cyclohexane, 1,3-bis (amino) are considered from the viewpoints of heat resistance and weather resistance and the cured product performance of the resulting epoxy resin composition. One or more selected from the group consisting of methyl) cyclohexane and 1,4-bis (aminomethyl) cyclohexane are preferred, and 1,3-bis (aminomethyl) cyclohexane is more preferred. An amine compound (A) can be used individually by 1 type or in combination of 2 or more types.

(Compound (B) having at least one epoxy group in the molecule)
The compound (B) used in the present invention may be a compound having at least one epoxy group in the molecule, and has two or more epoxy groups in the molecule from the viewpoint of reactivity with the amine compound (A). The compound which has is more preferable.
Among the compounds having two or more epoxy groups in the molecule, diglycidyl ether compounds are preferable, and in terms of heat resistance and the performance of the cured product of the resulting epoxy resin composition, an aromatic ring or alicyclic structure is present in the molecule. The diglycidyl ether compound containing is more preferable, and the diglycidyl ether compound containing an aromatic ring in the molecule is more preferable.
Especially, from a viewpoint of heat resistance and the hardened | cured material performance of the epoxy resin composition obtained, as a compound (B), the compound shown by following General formula (2) is preferable.

(In formula (2), R ^{11 to} R ¹⁴ are each independently an alkyl group having 1 to 6 carbon atoms, and a, b, c, and d are each independently an integer of 0 to 4. Multiple R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ may be the same or different from each other, X ¹ and X ² are each independently a single bond, —CH ₂ —, —CH (CH ₃ )-, or -C (CH ₃ ) _2- , R ¹⁵ is -CH ₂ CH (OH)-, or -CH (OH) CH _2- , n represents the average number of repeating units, and 0 A number of ~ 1.0.)
R ^{11 to} R ¹⁴ are preferably an alkyl group having 1 to 4 carbon atoms, and more preferably at least one selected from the group consisting of a methyl group, an ethyl group, an isopropyl group, and a t-butyl group.
All of a, b, c, and d are preferably integers of 0 to 2, more preferably 0 or 1, and still more preferably 0.
X ¹ and X ² are preferably —CH ₂ — or —C (CH ₃ ) ₂ —, and more preferably —C (CH ₃ ) ₂ —.
Moreover, from a viewpoint of the viscosity and sclerosis | hardenability of the addition reaction material obtained, it is preferable that n is 0-0.7, It is more preferable that it is 0-0.5, It is 0-0.3. More preferably, it is still more preferably 0.01-0.2.

Specific examples of compounds other than the compound represented by the general formula (2) among the compounds (B) used in the present invention include butyl glycidyl ether, phenyl glycidyl ether, m-cresyl glycidyl ether, and p-cresyl. Glycidyl ether, o-cresyl glycidyl ether, neodecanoic acid glycidyl ester, neopentyl glycol diglycidyl ether, 1,3-propanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl Examples include ether.
The said compound (B) can be used individually by 1 type or in combination of 2 or more types. Moreover, the said compound (B) may be the same compound as the epoxy resin used as a main ingredient of the epoxy resin composition of this invention mentioned later, and may differ.

In the addition reaction product of the amine compound (A) and the compound (B), the compound (B) was reacted at a ratio of more than 0.100 mol and less than 0.200 mol with respect to 1 mol of the amine compound (A). It is an addition reaction product.
When the reaction ratio of the compound (B) is 0.100 mol or less with respect to 1 mol of the amine compound (A), the effect of improving the curing rate of the resulting epoxy resin curing agent containing the addition reaction product is not sufficient. On the other hand, when the reaction ratio of the compound (B) is 0.200 mol or more with respect to 1 mol of the amine compound (A), the resulting epoxy resin curing agent and epoxy resin composition containing the addition reaction product have high viscosity. In particular, when used for CFRP molded by the high cycle RTM method, moldability and productivity are lowered. Furthermore, the mechanical strength and heat resistance of the obtained CFRP are also reduced. From the above viewpoint, the reaction ratio of the compound (B) to 1 mol of the amine compound (A) is preferably 0.110 mol or more, more preferably 0.115 mol or more, preferably less than 0.180 mol, more preferably Is 0.170 mol or less, more preferably 0.160 mol or less, still more preferably 0.150 mol or less, and still more preferably 0.140 mol or less.

  As an example of an addition reaction product of the amine compound (A) and the compound (B) when a compound having two epoxy groups in the molecule is used as the compound (B), the following structures (a) to Although what has (d) is mentioned, it is not limited to these. In the following structural formulas (a) to (d), A represents a residue of the amine compound (A), and B represents a residue of the compound (B).

The production method of the addition reaction product of the amine compound (A) and the compound (B) is not particularly limited, and a conventionally known method can be used. For example, a method may be mentioned in which an amine compound (A) is charged into a reactor, and a predetermined amount of the compound (B) is added at once, or added in portions by dropping or the like, followed by heating and reaction. The addition reaction is preferably performed in an inert atmosphere such as nitrogen gas.
The temperature and reaction time during the addition reaction can be appropriately selected according to the type of the compound (B) used. From the viewpoint of preventing reaction rate and productivity, and 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 compound (B) is completed.

(Curing accelerator)
The epoxy resin curing agent of the present invention may further contain a curing accelerator. The curing accelerator does not react with the addition reaction product and has a function of increasing the reactivity of the epoxy group in the epoxy resin. Therefore, when a curing accelerator is added to the epoxy resin curing agent of the present invention, the curing rate can be further improved.
The curing accelerator is not particularly limited. For example, phenolic compounds, organic acids, organic acid salts, tertiary amines, quaternary ammonium salts, imidazoles, organic phosphorus compounds, quaternary phosphonium salts, diazabicyclo Alkenes, organometallic salt compounds, boron compounds, metal halides and the like can be mentioned. Among these, from the viewpoint of achieving both fast curability and low viscosity, one or more selected from the group consisting of phenol compounds, organic acids and organic acid salts are preferred.

  As said phenol compound, if it is a compound which has at least 1 phenolic hydroxyl group in a molecule | numerator, it can use without a restriction | limiting especially. A phenol compound having a molecular weight of less than 1,000 is preferable from the viewpoint of exerting an effect even when the blending amount is small, and miscibility with the addition reaction product and the epoxy resin described later, and is represented by the following general formula (3). Compounds are more preferred.

(In Formula (3), R ¹ and R ² are each independently an OH group or an alkyl group having 1 to 4 carbon atoms. J and k are each independently an integer of 0 to 5, and j + k is 1) The plurality of R ¹ and the plurality of R ² may be the same or different from each other, but at least one of them is an OH group, Z is a single bond and an alkylene group having 1 to 6 carbon atoms. , An alkylidene group having 2 to 6 carbon atoms, a cycloalkylene group having 5 to 10 carbon atoms, a cycloalkylidene group having 5 to 10 carbon atoms, an arylalkylene group having 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15 carbon atoms, _{-S -, - SO -, -} SO 2 -, - O -, - CO -, - C (CF 3) 2 -, - CH (CF 3) -, - CF 2 -, - CONH-, or -COO -.)
In Formula (3), R ¹ and R ² are preferably OH groups, j and k are each independently an integer of 0 to 2, and j + k is preferably 1 to 3.
In Z in Formula (3), the alkylene group having 1 to 6 carbon atoms includes a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a hexamethylene group, and an alkylene group having 1 to 3 carbon atoms is preferable. . Examples of the alkylidene group having 2 to 6 carbon atoms include an ethylidene group (—CH (CH ₃ ) —) and a propylidene group (—C (CH ₃ ) ₂ —), and an alkylidene group having 2 to 3 carbon atoms is preferable. .
Examples of the cycloalkylene group having 5 to 10 carbon atoms include a cyclopentanediyl group, a cyclohexanediyl group, and a cyclooctanediyl group. Examples of the cycloalkylidene group having 5 to 10 carbon atoms include a cyclohexylidene group and a 3,5,5-trimethylcyclohexylidene group. Moreover, as an aryl site | part of a C7-C15 arylalkylene group and a C7-C15 arylalkylidene group, ring group C6-C14 aryl groups, such as a phenyl group, a naphthyl group, a biphenyl group, an anthryl group, Is mentioned.
Among the above, Z is preferably at least one selected from the group consisting of a single bond, an alkylene group having 1 to 3 carbon atoms, and an alkylidene group having 2 to 3 carbon atoms, and is a single bond, methylene group, ethylidene group, or propylidene. It is preferably a group, more preferably a methylene group, an ethylidene group, or a propylidene group.

Specific examples of the compound represented by the general formula (3) include bisphenol A [4,4 ′-(propane-2,2-diyl) diphenol], bisphenol F [bis (4-hydroxyphenyl) methane], Bisphenol AP [1,1-bis (4-hydroxyphenyl) -1-phenylethane], bisphenol AF [2,2-bis (4-hydroxyphenyl) hexafluoropropane], bisphenol B [2,2-bis (4 -Hydroxyphenyl) butane], bisphenol BP [bis (4-hydroxyphenyl) diphenylmethane], bisphenol S [bis (4-hydroxyphenyl) sulfone], bisphenol E [1,1-bis (4-hydroxyphenyl) ethane], Styrenated phenol, hydroxybiphenyl, dihydroxybifu Alkylsulfonyl and the like. Among these, bisphenol A [4,4 ′-(propane-2,2-diyl) diphenol], bisphenol F [bis (4-hydroxyphenyl) methane], and bisphenol E from the viewpoint of solubility in the curing agent. At least one selected from the group consisting of [1,1-bis (4-hydroxyphenyl) ethane] and styrenated phenol is preferred, and bisphenol A [4,4 from the viewpoint of exerting an effect even if the blending amount is small. '-(Propane-2,2-diyl) diphenol], bisphenol F [bis (4-hydroxyphenyl) methane], and bisphenol E [1,1-bis (4-hydroxyphenyl) ethane] More preferably, at least one selected from the above.
The styrenated phenol is preferably a 1: 1 adduct of styrene and phenol, and is a compound represented by the following formula (3-1). The styrenated phenol is preferably composed mainly of a compound represented by the following formula (3-1), but it is a multiple addition such as a 2: 1 adduct of styrene and phenol or a 3: 1 adduct of styrene and phenol. The body may be contained. In the present specification, the “main component” means that the content is 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more (upper limit is 100%) when all the constituents are 100% by mass. Mass%). Examples of commercially available styrenated phenols include “Kumanox-3110”, “Kumanox-3111”, “Kumanox-3114”, “Kumanox-3120”, “Kumanox-SP” manufactured by Kumho Petrochemical, and the like.

  Examples of phenol compounds other than the compound represented by the general formula (3) include phenol, cresol, hydroquinone, 1-naphthol, 2-naphthol, resorcin, phenol novolac resin, p-isopropylphenol, p-tert-butylphenol, nonylphenol, and the like. Is mentioned.

Examples of the organic acids used as the curing accelerator include carboxylic acid compounds and sulfonic acid compounds.
Examples of carboxylic acid compounds include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butanoic acid, 2-ethylhexanoic acid and benzoic acid; hydroxymonocarboxylic acids such as lactic acid and salicylic acid; oxalic acid, malonic acid, maleic acid, And polyvalent carboxylic acids such as itaconic acid, fumaric acid, adipic acid, sebacic acid, isophthalic acid, trimellitic acid, pyromellitic acid, tetrahydrophthalic acid and hexahydrophthalic acid.
Examples of the sulfonic acid compound include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, trifluoromethanesulfonic acid and the like.
Among these, as the organic acids, sulfonic acid compounds are preferable, and p-toluenesulfonic acid is more preferable.
Examples of organic acid salts include salts of the above organic acids. For example, imidazole salts, substituted imidazole salts, diazabicycloundecene (DBU) salts, diazabicyclononenes of the above carboxylic acid compounds or sulfonic acid compounds. (DBN) salt, diazabicyclooctane (DABCO) salt, tetraethylammonium salt, and tetrabutylammonium salt.

Examples of the curing accelerator other than the above include tertiary ethylenes, triethylenediamine, triethanolamine, benzyldimethylamine, dimethylcyclohexylamine, 2- (dimethylaminomethyl) phenol, and the like. Examples of quaternary ammonium salts include tetraethylammonium bromide and tetrabutylammonium bromide.
Examples of imidazoles include 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-ethyl-4-methylimidazole, and 1-benzyl-2-methylimidazole. Etc.
Examples of the organic phosphorus compound include triphenylphosphine, diphenylphosphine, tributylphosphine, and triphenyl phosphite. Examples of the quaternary phosphonium salts include tetraphenylphosphonium bromide and tetra-n-butylphosphonium bromide. .
Examples of diazabicycloalkenes include 1,8-diazabicyclo [5.4.0] undecene-7.
Examples of the organic metal salt compound include zinc octylate and tin octylate. Examples of the boron compound include boron trifluoride and triphenyl borate. Examples of the metal halide include zinc chloride and stannic chloride.
A hardening accelerator can be used individually by 1 type or in combination of 2 or more types.

  The content of the curing accelerator in the epoxy resin curing agent is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the addition reaction product. When the content of the curing accelerator with respect to 100 parts by mass of the addition reaction product is 1 part by mass or more, an effect of improving curability is obtained. Further, if it is 20 parts by mass or less, the epoxy resin curing agent and the epoxy resin composition containing the epoxy resin composition do not have high viscosity, and are particularly suitable for CFRP molded by the high cycle RTM method. The mechanical strength and heat resistance are not lowered. From the above viewpoint, the content of the curing accelerator in the epoxy resin curing agent is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, more preferably 15 parts by mass with respect to 100 parts by mass of the addition reaction product. It is 10 parts by mass or less, more preferably 10 parts by mass or less.

The epoxy resin curing agent of the present invention may contain a known curing agent other than the addition reaction product, a known additive, a solvent, and the like. Examples of the curing agent other than the addition reaction product include polyamine compounds other than the component (A) or modified products thereof. Examples of the polyamine compound include chain aliphatic polyamine compounds such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexamethylenediamine, 2-methylpentamethylenediamine, and trimethylhexamethylenediamine; Sendiamine, isophoronediamine, norbornanediamine, tricyclodecanediamine, adamantanediamine, diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-3,6-diethylcyclohexane, diaminodiethylmethylcyclohexane, 3 , 3′-dimethyl-4,4′-diaminodicyclohexylmethane, polyaryl having an alicyclic structure such as 4,4′-diaminodicyclohexylmethane Aromatic compounds such as phenylenediamine, diaminodiphenylmethane and diaminodiphenylsulfone; polyamine compounds having a heterocyclic structure such as N-aminomethylpiperazine and N-aminoethylpiperazine; polyether polyamine compounds and their Mannich Modified products, epoxy-modified products, Michael adducts, Michael addition / polycondensates, styrene-modified products, polyamide-modified products, and the like. These can be used alone or in combination of two or more.
However, from the viewpoint of efficiently expressing the effect of the present invention, the content of the addition reaction product is preferably 50% by mass or more, more preferably 70% by mass or more, based on the total amount of the epoxy resin curing agent of the present invention. More preferably, it is 80% by mass or more, more preferably 85% by mass or more, and still more preferably 90% by mass or more (the upper limit is 100% by mass).

  The epoxy resin curing agent of the present invention has a viscosity at a temperature of 25 ° C. of preferably 10,000 mPa · s or less, more preferably 8,000 mPa · s or less, further preferably 5,000 mPa · s or less, and still more preferably 3, 000 mPa · s or less, more preferably 2,000 mPa · s or less, even more preferably 1,000 mPa · s or less, still more preferably 800 mPa · s or less, and even more preferably 500 mPa · s or less. When the viscosity at a temperature of 25 ° C. is 10,000 mPa · s or less, mixing with an epoxy resin is easy, and productivity is improved when used for CFRP applications. The lower limit of the viscosity of the epoxy resin curing agent at 25 ° C. is not particularly limited, but is preferably 10 mPa · s or more, more preferably 50 mPa · s or more, and still more preferably 100 mPas, from the viewpoint of miscibility with the epoxy resin. -It is more than s.

[Epoxy resin composition]
The epoxy resin composition of the present invention contains the epoxy resin curing agent of the present invention and an epoxy resin. Any epoxy resin having a glycidyl group that reacts with the active amine hydrogen in the epoxy resin curing agent of the present invention can be used as the epoxy resin, but from the viewpoint of excellent mechanical strength of the cured product. An epoxy resin containing an aromatic ring or alicyclic structure in the molecule is preferred, and an epoxy resin containing an aromatic ring in the molecule is more preferred. Among these, an epoxy resin represented by the following general formula (4) is particularly preferred from the viewpoint of low viscosity and ensuring the mechanical strength of the cured product.

(In formula (4), R ^{21 to} R ²⁴ are each independently an alkyl group having 1 to 6 carbon atoms, and p, q, r, and s are each independently an integer of 0 to 4. ²¹ , the plurality of R ²² , the plurality of R ²³ , and the plurality of R ²⁴ may all be the same or different from each other, Y ¹ and Y ² are each independently a single bond, —CH ₂ —, —CH ( CH ₃ ) —, or —C (CH ₃ ) ₂ —, R ²⁵ is —CH ₂ CH (OH) —, or —CH (OH) CH ₂ —, m represents the average number of repeating units, It is a number from 0 to 0.2.)
R ^{21 to} R ²⁴ are preferably an alkyl group having 1 to 4 carbon atoms, and more preferably at least one selected from the group consisting of a methyl group, an ethyl group, an isopropyl group, and a t-butyl group.
p, q, r, and s are all preferably integers of 0 to 2, more preferably 0 or 1, and still more preferably 0.
Y ¹ and Y ² are preferably —CH ₂ — or —C (CH ₃ ) ₂ —, and more preferably —C (CH ₃ ) ₂ —.
Moreover, m is preferably 0 to 0.15 and more preferably 0.01 to 0.1 from the viewpoint of low viscosity and ensuring the mechanical strength of the cured product.

The epoxy equivalent of the epoxy resin is preferably 300 g / equivalent or less, more preferably 220 g / equivalent or less, and still more preferably 200 g / equivalent or less, from the viewpoint of achieving both low viscosity and fast curability of the epoxy resin composition. More preferably, it is 180 g / equivalent or less.
An epoxy resin may be used individually by 1 type, and may use 2 or more types together.

  The epoxy resin composition of the present invention further uses other components such as fillers, modifying components such as plasticizers, flow adjusting components such as thixotropic agents, pigments, leveling agents, tackifiers, and elastomer fine particles. You may make it contain according to.

The content of the epoxy resin curing agent in the epoxy resin composition of the present invention is the ratio of the number of active amine hydrogens in the epoxy resin curing agent to the number of epoxy groups in the epoxy resin (active amine hydrogen in the epoxy resin curing agent). Number / number of epoxy groups in the epoxy resin) is preferably 1 / 0.8 to 1 / 1.2, more preferably 1 / 0.9 to 1 / 1.1, and still more preferably 1/1. is there.
The viscosity of the epoxy resin composition of the present invention at a temperature of 40 ° C. is preferably 5,000 mPa · s or less, more preferably 2,000 mPa · s or less, further preferably 1,500 mPa · s or less, and still more preferably 1, It is 200 mPa · s or less, more preferably 1,000 mPa · s or less, still more preferably 800 mPa · s or less, and still more preferably 750 mPa · s or less. When the viscosity at a temperature of 40 ° C. is 5,000 mPa · s or less, productivity is improved when used for CFRP. The lower limit of the viscosity of the epoxy resin composition at a temperature of 40 ° C. is not particularly limited, but suppresses the occurrence of turbulence in the carbon fiber due to a turbulent flow in the mold due to an increase in the Reynolds number in CFRP molding. From the viewpoint, it is preferably 150 mPa · s or more, more preferably 300 mPa · s or more.

In the epoxy resin composition of the present invention, the gelation time at a temperature of 80 ° C. is preferably 12 minutes or less, more preferably 10 minutes or less, and even more preferably 9.0 minutes or less, from the viewpoint of fast curing. From the viewpoint of workability, the gelation time is preferably 0.5 minutes or more, more preferably 1.0 minutes or more.
The gelation time can be measured by a method described in Examples using a rheometer. Specifically, using a rheometer, the storage elastic modulus G ′ and loss elastic modulus G ″ of the epoxy resin composition are measured at a temperature of 80 ° C., a frequency of 1 Hz, and a distance between plates of 0.5 mm, and G ′ and G ′. The point at which 'intersects is the gel time.

  There is no restriction | limiting in particular in the manufacturing method of the epoxy resin composition of this invention, An epoxy resin hardening | curing agent, an epoxy resin, and another component as needed can be mixed and manufactured using a well-known method and apparatus. There is no restriction | limiting in particular also in the mixing order of each component contained in an epoxy resin composition.

The epoxy resin curing agent and the epoxy resin composition containing the epoxy resin curing agent of the present invention are preferably used for fiber-reinforced composite materials because they have the characteristics of being fast-curing and having a low viscosity. It is preferable for a composite material.
A fiber reinforced composite material (FRP) includes a cured product of the epoxy resin composition and reinforcing fibers, and after impregnating the epoxy resin composition with reinforcing fibers, the composition is cured. Can be obtained. The FRP may further contain a foam material in addition to the cured product of the epoxy resin composition and the reinforcing fiber.
Examples of the reinforcing fiber include glass fiber, carbon fiber, boron fiber, and metal fiber. Reinforcing fibers may be used alone or in combination of two or more. Among these, carbon fiber is preferable from the viewpoint of the strength and light weight of the composite material to be obtained.
Although there is no restriction | limiting in particular as a foam material, For example, the foam material comprised from resin materials, such as a polyvinyl chloride resin, a polyurethane resin, a polystyrene resin, polyolefin resin, an acrylic resin, a phenol resin, a polymethacrylimide resin, an epoxy resin, is mentioned It is done.
Hereinafter, the carbon fiber reinforced composite material including the cured product of the epoxy resin composition and carbon fibers will be described.

[Carbon fiber reinforced composite (CFRP)]
The carbon fiber reinforced composite material (CFRP) of the present invention includes a cured product of the epoxy resin composition and carbon fibers. After impregnating the epoxy resin composition into carbon fibers, the composition is It can be obtained by curing. In addition to the cured product of the epoxy resin composition and the carbon fiber, the CFRP may further contain a reinforcing fiber other than the carbon fiber and the foamed material.

(Carbon fiber)
The carbon fiber used in the CFRP of the present invention may be manufactured using rayon, polyacrylonitrile (PAN) or the like as a raw material, or manufactured by spinning a pitch such as petroleum or coal as a raw material. Also good. Examples of the form of the carbon fiber include various forms such as monofilaments or multifilaments arranged so as to cross one direction or alternately, a fabric such as a knitted fabric, a nonwoven fabric, or a mat. Of these, monofilaments, fabrics, non-woven fabrics or mats are preferred, and fabrics are more preferred. In addition, a recycled product obtained by reusing carbon fiber scraps, or a recycled product obtained by removing resin from CFRP can be used.

  The average fiber diameter of the carbon fibers is preferably 1 to 100 μm, more preferably 3 to 50 μm, and still more preferably 4 to 20 μm. When the average fiber diameter is within this range, processing is easy and the resulting CFRP has excellent elastic modulus and strength. The average fiber diameter can be measured by observation with a scanning electron microscope (SEM) or the like. More than 50 fibers can be selected at random, the length can be measured, and the average fiber diameter of the number average can be calculated.

  The fineness of the carbon fiber is preferably 20 to 4,500 tex, more preferably 50 to 4,000 tex. When the fineness is within this range, the epoxy resin composition can be easily impregnated, and the resulting composite material has excellent elastic modulus and strength. The fineness can be obtained by obtaining the weight of long fibers having an arbitrary length and converting it to the weight per 1,000 m. Usually, carbon fibers having a filament number of about 500 to 60,000 can be preferably used.

[Method for producing carbon fiber reinforced composite]
Although there is no restriction | limiting in particular in the manufacturing method of the carbon fiber reinforced composite material of this invention, Since the epoxy resin hardening | curing agent and epoxy resin composition of this invention are quick-hardening, an epoxy resin hardening | curing agent and an epoxy resin are shape | molded. It is preferable that the carbon fiber is impregnated and cured preferably within 10 minutes, more preferably within 5 minutes after mixing immediately before.
From this point of view, the method for producing the carbon fiber reinforced composite material of the present invention includes a low pressure RTM method, a medium pressure RTM method, a high pressure RTM method, a compression RTM method, a liquid compression molding method, a liquid laydown method, a spray laydown method, and a surface RTM method. It is preferable to have a step of molding by a prepreg compression molding method or a liquid cast molding method. Among these molding methods, from the viewpoint of applying to the high cycle RTM method, the low pressure RTM method, the medium pressure RTM method, or the high pressure RTM method is preferable, the medium pressure RTM method or the high pressure RTM method is more preferable, and from the viewpoint of molding speed. Is more preferably the high pressure RTM method.
In this specification, “low pressure” in the low pressure RTM method means that the pressure at the time of pumping and mixing the epoxy resin that is the main component of the epoxy resin composition and the epoxy resin curing agent is less than 0.5 MPa. It means that. Similarly, the “intermediate pressure” in the medium pressure RTM method means that the pressure is 0.5 MPa or more and less than 7 MPa, and the “high pressure” in the high pressure RTM method means that the pressure is 7 MPa or more and 20 MPa or less.
In the above molding method, since the epoxy resin curing agent of the present invention and the epoxy resin can be mixed and used immediately before molding, the pot life of the epoxy resin composition is not so required. In addition, since the epoxy resin composition is fast-curing and has a low viscosity, filling into the mold and impregnation into the carbon fiber is fast and cures quickly, so that the molding time can be greatly shortened. Therefore, the epoxy resin curing agent and the epoxy resin composition of the present invention are particularly suitable for the molding method. Moreover, by using the above molding method, the epoxy resin curing agent and the epoxy resin composition of the present invention can be applied to produce medium to large CFRP for automobile structural materials and building materials with high productivity. .

  In the high-pressure RTM method, it is preferable to use a collision mixing mixer as an apparatus for mixing the epoxy resin that is the main component of the epoxy resin composition and the epoxy resin curing agent. For example, carbon fibers are placed in a pair of upper and lower molds and sealed, and the inside of the mold is decompressed. Next, the epoxy resin, which is the main component of the epoxy resin composition, and the epoxy resin curing agent are filled in separate tanks, each of which is discharged from a very small hole (orifice) at high speed, and inside the mixing chamber of the collision mixing mixer. Crash mixing. The epoxy resin composition thus prepared is injected into the mold at high pressure to impregnate the carbon fiber, and then the epoxy resin is cured.

In the low pressure RTM method, it is preferable to use a dynamic mixer as an apparatus for mixing an epoxy resin that is a main component of the epoxy resin composition and an epoxy resin curing agent. The dynamic mixer includes a cylindrical high-speed rotating body having irregularities on the surface. For example, the epoxy resin that is the main ingredient of the epoxy resin composition and the epoxy resin curing agent are filled in separate tanks, each of which is fed to a dynamic mixer, and the two liquids of the main ingredient and the curing agent are mixed by the rotating body. . The epoxy resin composition thus prepared is poured into a mold and impregnated in carbon fibers, and then the epoxy resin is cured. The low-pressure RTM method is advantageous when the blending ratio of the epoxy resin and the epoxy resin curing agent is greatly different, or from the viewpoint of equipment cost and space saving of the equipment.
In the medium pressure RTM method, it is preferable to use a static mixer as an apparatus for mixing an epoxy resin, which is the main component of the epoxy resin composition, and an epoxy resin curing agent. A static mixer is a tubular reactor incorporating one or more static mixers composed of a large number of mixing elements. For example, the epoxy resin that is the main component of the epoxy resin composition and the epoxy resin curing agent are filled in separate tanks, and each is sent to a static mixer. By passing two liquids of the main agent and the curing agent through the twisted element of the static mixer, the two liquids are mixed by the action of division, conversion, inversion and the like. The epoxy resin composition thus prepared is poured into a mold and impregnated in carbon fibers, and then the epoxy resin is cured. The medium pressure RTM method is advantageous from the viewpoints of being able to pump the epoxy resin composition into the mold and apparatus cost.

  When the CFRP further includes a foam material in addition to the cured product of the epoxy resin composition and the carbon fiber, the carbon fiber and the foam material may be disposed in the mold and the CFRP may be manufactured in the same manner as described above. it can.

  The epoxy resin curing agent and the epoxy resin composition of the present invention can also be suitably used for the liquid compression molding (LCM) method and the liquid laydown method. In the LCM method and the liquid laydown method, an epoxy resin composition is cast and impregnated on carbon fiber (on the carbon fiber and foam material when CFRP further includes a foam material), and then heated and compressed to form an epoxy resin. Is cured.

In the CFRP molding, the temperature at which the epoxy resin composition is injected into the mold or impregnated into the carbon fiber is preferably 30 to 120 ° C, more preferably 50 to 100 ° C. When the epoxy resin curing agent and the epoxy resin are supplied from separate tanks and mixed immediately before molding, the temperature at the time of mixing the epoxy resin curing agent and the epoxy resin can also be set individually. The temperature during mixing of the epoxy resin curing agent is preferably 5 to 30 ° C, more preferably 10 to 25 ° C, from the viewpoint of suppressing an increase in viscosity. Moreover, although the temperature at the time of mixing of an epoxy resin can be suitably adjusted according to the viscosity of an epoxy resin, Preferably it is 30-120 degreeC, More preferably, it is 50-100 degreeC.
The impregnation time of the epoxy resin composition into the carbon fiber is preferably 0.1 to 15 minutes, more preferably 0.2 to 10 minutes, and further preferably 0.5 to 5 minutes from the viewpoint of moldability and productivity. It is.

  The curing temperature of the epoxy resin composition is preferably 50 to 200 ° C, more preferably 80 to 150 ° C, and still more preferably 100 to 150 ° C. When the curing temperature is 50 ° C. or higher, the epoxy resin is sufficiently cured and the resulting CFRP has excellent mechanical properties. Moreover, if it is 200 degrees C or less, the cost concerning mold temperature adjustment will be low. The curing time of the epoxy resin composition is preferably 0.1 to 15 minutes, more preferably 0.2 to 10 minutes, and further preferably 0.5 to 5 minutes from the viewpoints of moldability and productivity.

  Using the epoxy resin curing agent or epoxy resin composition of the present invention, CFRP can be produced with high productivity by the molding method described above. The carbon fiber reinforced composite material of the present invention is preferably an automotive structural material or a building material, particularly an automotive structural material. Automotive structural materials include bumpers, spoilers, cowlings, front grilles, garnishes, bonnets, trunk lids, fender panels, door panels, roof panels, instrument panels, door trims, quarter trims, roof linings, pillar garnishes, deck trims, tonneau boards. , Package tray, dashboard, console box, kicking plate, switch base, seat back board, seat frame, armrest, sun visor, intake manifold, engine head cover, engine under cover, oil filter housing, and the like.

  EXAMPLES 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. Various evaluations and measurements of the epoxy resin curing agent and the cured epoxy resin were performed according to the following methods.

(viscosity)
The viscosity of the epoxy resin curing agent and the epoxy resin composition was measured using an E type viscometer “TVE-22H type viscometer cone plate type” (manufactured by Toki Sangyo Co., Ltd.). The epoxy resin curing agent was measured at 25 ° C., and the epoxy resin composition was measured at 40 ° C. The lower the viscosity, the higher the filling property during molding and the better the molding property.

(Gel time)
Evaluation was carried out using a rheometer “ARES-G2” (manufactured by TA Instruments). An epoxy resin composition is filled between aluminum plates heated to 80 ° C., storage elastic modulus G ′ and loss elastic modulus G ″ are measured at a temperature of 80 ° C., a frequency of 1 Hz, and a distance between plates of 0.5 mm. The point where 'and G''intersect was defined as the gel time. A shorter gelation time indicates faster curing.

Example 1 (Production of addition reaction product)
To a separable flask having an internal volume of 2 liters equipped with a stirrer, a thermometer, a nitrogen introduction tube, a dropping funnel and a cooling tube, 1,3-bis (aminomethyl) cyclohexane (1,3- 569 g (4.0 mol) of BAC, manufactured by Mitsubishi Gas Chemical Co., Ltd., cis / trans ratio = 77/23) was charged, and the temperature was raised to 80 ° C. with stirring under a nitrogen stream. While maintaining the temperature at 80 ° C., 186 g of the bisphenol A type liquid epoxy resin (“jER828”, manufactured by Mitsubishi Chemical Corporation), which is the compound (B), is 0.125 mol per 1 mol of 1,3-BAC. It was dripped over 2 hours. After completion of the dropwise addition, the temperature was raised to 100 ° C. and the reaction was performed for 2 hours to obtain 755 g (active hydrogen equivalent: 50.3) of 1,3-BAC jER828 addition reaction product.
The epoxy resin jER828 used as the compound (B) is represented by the following structural formula, where n = 0.11 and the epoxy equivalent is 186 g / equivalent.

In the above formula, R ¹⁵ is —CH ₂ CH (OH) — or —CH (OH) CH ₂ —.

(Preparation of epoxy resin composition)
The addition reaction product obtained as described above was used as an epoxy resin curing agent. This epoxy resin curing agent and the main agent bisphenol A type liquid epoxy resin ("jER825", manufactured by Mitsubishi Chemical Corporation), the number of active amine hydrogens in the epoxy resin curing agent, and the epoxy resin epoxy as the main agent The epoxy resin composition was prepared by blending and mixing so that the number of radicals was equimolar.
About the obtained epoxy resin hardening | curing agent and epoxy resin composition, it evaluated by the above-mentioned method. The results are shown in Table 1. The epoxy resin jER825 is represented by the following structural formula, m = 0.035, and the epoxy equivalent is 175 g / equivalent.

In the above formula, R ²⁵ is —CH ₂ CH (OH) — or —CH (OH) CH ₂ —.

Example 2
10 g of bisphenol A (4,4 ′-(propane-2,2-diyl) diphenol, manufactured by Kanto Chemical Co., Ltd.) is added as a curing accelerator to 100 g of the addition reaction product obtained in Example 1 above. And mixed to obtain an epoxy resin curing agent.
This epoxy resin curing agent and the main agent bisphenol A type liquid epoxy resin ("jER825", manufactured by Mitsubishi Chemical Corporation), the number of active amine hydrogen of the epoxy resin curing agent and the epoxy in the epoxy resin as the main agent The epoxy resin composition was prepared by blending and mixing so that the number of radicals was equimolar.
About the obtained epoxy resin hardening | curing agent and epoxy resin composition, it evaluated by the above-mentioned method. The results are shown in Table 1.

Examples 3-4
In Example 1, an addition reaction product was obtained in the same manner as in Example 1 except that the amount (addition amount) of jER828 as compound (B) was changed as shown in Table 1. Moreover, the epoxy resin composition was prepared by the same method as Example 1 using this addition reaction thing as an epoxy resin hardening | curing agent.
About the obtained epoxy resin hardening | curing agent and epoxy resin composition, it evaluated by the above-mentioned method. The results are shown in Table 1.

Example 5
In Example 1, addition was performed in the same manner as in Example 1 except that metaxylylenediamine (MXDA, manufactured by Mitsubishi Gas Chemical Co., Inc.) was used as the amine compound (A) instead of 1,3-BAC. A reaction product was obtained. Moreover, the epoxy resin composition was prepared by the same method as Example 1 using this addition reaction thing as an epoxy resin hardening | curing agent.
About the obtained epoxy resin hardening | curing agent and epoxy resin composition, it evaluated by the above-mentioned method. The results are shown in Table 1.

Examples 6-7
In Example 1, the above-described bisphenol A type liquid epoxy resin “jER825” (manufactured by Mitsubishi Chemical Corporation) was used as the compound (B) instead of jER828, and the amount used (addition amount) thereof was as shown in Table 1. Except that, an addition reaction product was obtained in the same manner as in Example 1. Moreover, the epoxy resin composition was prepared by the same method as Example 1 using this addition reaction thing as an epoxy resin hardening | curing agent.
About the obtained epoxy resin hardening | curing agent and epoxy resin composition, it evaluated by the above-mentioned method. The results are shown in Table 1.

Example 8
3 g of p-toluenesulfonic acid monohydrate was mixed and mixed with 100 g of the addition reaction product obtained in Example 6 to obtain an epoxy resin curing agent.
This epoxy resin curing agent and the main agent bisphenol A type liquid epoxy resin (“jER825”, manufactured by Mitsubishi Chemical Corporation), the number of active amine hydrogen in the epoxy resin curing agent, and the main epoxy resin in the epoxy resin The epoxy resin composition was prepared by blending and mixing so that the number of epoxy groups was equimolar.
About the obtained epoxy resin hardening | curing agent and epoxy resin composition, it evaluated by the above-mentioned method. The results are shown in Table 1.

Comparative Example 1
Instead of the addition reaction product obtained in Example 1, 1,3-bis (aminomethyl) cyclohexane (1,3-BAC, manufactured by Mitsubishi Gas Chemical Co., Inc., cis / trans ratio = 77) was used as an epoxy resin curing agent. Except for using / 23), an epoxy resin composition was prepared in the same manner as in Example 1 and evaluated by the method described above. The results are shown in Table 1.

Comparative Examples 2-3
In Example 1, an addition reaction product was obtained in the same manner as in Example 1 except that the amount (addition amount) of jER828 as compound (B) was changed as shown in Table 1. Moreover, the epoxy resin composition was prepared by the same method as Example 1 using this addition reaction thing as an epoxy resin hardening | curing agent.
About the obtained epoxy resin hardening | curing agent and epoxy resin composition, it evaluated by the above-mentioned method. The results are shown in Table 1.

Comparative Example 4
In the same manner as in Example 1, except that metaxylylenediamine (MXDA, manufactured by Mitsubishi Gas Chemical Co., Inc.) was used as an epoxy resin curing agent instead of the addition reaction product obtained in Example 1. Resin compositions were prepared and evaluated by the methods described above. The results are shown in Table 1.

  From Table 1, it can be seen that the epoxy resin curing agent and the epoxy resin composition of the present invention are fast-curing and have a relatively low viscosity. Therefore, it is suitable for manufacturing various molded articles using a molding method such as a high cycle RTM method. On the other hand, in the epoxy resin hardening | curing agent and epoxy resin composition of Comparative Examples 1-4, it was difficult to make quick cure and low viscosity compatible.

(Manufacturing of CFRP and evaluation of releasability)
The epoxy resin compositions of Examples 1, 2, 6, 8 and Comparative Example 1 were subjected to hand lay-up molding at room temperature to produce a carbon fiber fabric (“CO6343” manufactured by Toray Industries, Inc., T300 plain weave cloth, 3K, 198 g). / M ² , 0.25 mm thickness, 4 ply) to prepare a CFRP substrate. Subsequently, the CFRP substrate was placed on an aluminum upper and lower mold heated in advance in an oven to 120 ° C., the mold was quickly closed, and the curing behavior and release properties after a predetermined time elapsed were evaluated.
Table 2 shows the time until the CFRP substrate is completely cured and can be released. The shorter this time, the faster the curing and release, and the better the CFRP productivity.

  From Table 2, since the epoxy resin curing agent of this application example and the epoxy resin composition using the same are fast-curing even when applied to CFRP applications, the time required to release the mold is fast. It turns out that it is excellent also in property.

  According to the present invention, it is possible to provide an epoxy resin curing agent and an epoxy resin composition that are fast-curing and low-viscosity capable of producing CFRP such as automobile structural materials and building materials with high productivity by a high cycle RTM method or the like. it can. When the epoxy resin composition is used as a CFRP matrix resin, it has excellent carbon fiber impregnation properties and is fast-curing, so that it takes only a short time to release from the mold, and CFRP production. Can be improved.

Claims (13)

The compound (B) having at least one epoxy group in the molecule was reacted at a ratio of more than 0.100 mol and less than 0.200 mol with respect to 1 mol of the amine compound (A) represented by the following general formula (1). An epoxy resin curing agent containing an addition reaction product.
_{H 2 N-H 2 C-} A-CH 2 -NH 2 (1)
(In Formula (1), A is a cyclohexylene group or a phenylene group.)   The epoxy resin hardening | curing agent of Claim 1 whose A is a cyclohexylene group in the said General formula (1).   The epoxy resin curing agent according to claim 1 or 2, wherein the compound (B) is a diglycidyl ether compound having an aromatic ring in the molecule. The epoxy resin hardening | curing agent of Claim 3 whose said compound (B) is a compound shown by following General formula (2).

(In formula (2), R ^{11 to} R ¹⁴ are each independently an alkyl group having 1 to 6 carbon atoms, and a, b, c, and d are each independently an integer of 0 to 4. Multiple R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ may be the same or different from each other, X ¹ and X ² are each independently a single bond, —CH ₂ —, —CH (CH ₃ )-, or -C (CH ₃ ) _2- , R ¹⁵ is -CH ₂ CH (OH)-, or -CH (OH) CH _2- , n represents the average number of repeating units, and 0 A number of ~ 1.0.)   Furthermore, the epoxy resin hardening | curing agent of any one of Claims 1-4 containing a hardening accelerator.   The epoxy resin composition containing the epoxy resin hardening | curing agent of any one of Claims 1-5, and an epoxy resin.   The epoxy resin composition according to claim 6, wherein the epoxy resin is an epoxy resin containing an aromatic ring or an alicyclic structure in the molecule. The epoxy resin composition according to claim 7, wherein the epoxy resin is an epoxy resin represented by the following general formula (4).

(In formula (4), R ^{21 to} R ²⁴ are each independently an alkyl group having 1 to 6 carbon atoms, and p, q, r, and s are each independently an integer of 0 to 4. ²¹ , the plurality of R ²² , the plurality of R ²³ , and the plurality of R ²⁴ may all be the same or different from each other, Y ¹ and Y ² are each independently a single bond, —CH ₂ —, —CH ( CH ₃ ) —, or —C (CH ₃ ) ₂ —, R ²⁵ is —CH ₂ CH (OH) —, or —CH (OH) CH ₂ —, m represents the average number of repeating units, It is a number from 0 to 0.2.)   The epoxy resin composition according to any one of claims 6 to 8, wherein the viscosity at a temperature of 40 ° C is 5,000 mPa · s or less.   The epoxy resin composition according to any one of claims 6 to 9, which is for a carbon fiber reinforced composite material.   The carbon fiber reinforced composite material containing the hardened | cured material of the epoxy resin composition of any one of Claims 6-10, and carbon fiber.   The carbon fiber reinforced composite material according to claim 11, which is a structural material for automobiles.   Having a step of molding by a low pressure RTM method, a medium pressure RTM method, a high pressure RTM method, a compression RTM method, a liquid compression molding method, a liquid laydown method, a spray laydown method, a surface RTM method, a prepreg compression molding method or a liquid cast molding method. The manufacturing method of the carbon fiber reinforced composite material of Claim 11 or 12.