JP2023131013A - Curing agent composition, epoxy resin composition and cured product - Google Patents

Abstract

To provide a curing agent composition capable of providing a curable resin composition that has excellent appearance stability and is combined with epoxy resin to exhibit excellent curability.SOLUTION: A curing agent composition contains component (A): aromatic amine, component (B): salicylic acid, and component (C): a hydroxy group-containing aromatic solvent. Relative to 100 pts.mass of the component (A), the content of the component (B) is 50 pts.mass or more and 200 pts.mass. Preferably, the component (A) aromatic amine should be a compound represented by the formula (1) (where R1's independently represent a C1 to 4 aliphatic hydrocarbon group, a C1 to 4 alkoxy group or a C1 to 4 thioalkyl group and n represents a number of 2 or more and 4 or less).SELECTED DRAWING: None

Description

The present invention relates to a curing agent composition, and more particularly to a curing agent composition containing an aromatic amine, salicylic acid, and a hydroxyl group-containing aromatic solvent.

A cured product obtained by curing an epoxy resin composition using an aromatic amine and an epoxy resin has excellent physical properties due to the interaction between rigid rings such as aromatic rings contained in the aromatic amine. For this reason, the epoxy resin composition is suitable for applications that are exposed to severe corrosive environments, such as steel structures and concrete structures built near seashores and rivers, as well as for building exterior materials and flooring. It is also used in paints and repair materials.

Aromatic amines are less reactive than aliphatic amines and alicyclic amines, which are commonly used as curing agents for epoxy resins, so a catalyst is often used during curing. As the catalyst, an acid catalyst, an amine catalyst, etc. are used. Among them, salicylic acid has a high catalytic ability, and for example, Patent Document 1 describes an anticorrosive epoxy resin paint in which salicylic acid is used in combination with an epoxy resin and a modified aromatic amine. According to the same document, it is stated that the epoxy resin paint can be used to obtain a cured product with excellent corrosion resistance and chemical resistance.

Japanese Patent Application Publication No. 2009-235403

Upon investigation by the present inventor, it was found that an epoxy resin composition that uses a combination of an epoxy resin and a mixture of an aromatic amine and salicylic acid has a problem in curing speed. One way to improve the curing rate is to increase the amount of catalyst, but salicylic acid is a highly crystalline compound, and as the amount added to the aromatic amine increases, the resulting curing rate increases. It has been found that the drug composition crystallizes over time during storage.
Therefore, the problem to be solved by the present invention is to provide a curing agent for epoxy resin that has an excellent curing speed, can obtain a cured product that can withstand severe corrosive environments, and has good storage stability. be.

Therefore, the inventors of the present invention conducted extensive research and found that by using an aromatic amine, salicylic acid, and a hydroxyl group-containing aromatic solvent in combination, and by setting the aromatic amine and salicylic acid at a predetermined ratio, a product with excellent appearance stability and a fast curing speed was found. An excellent aromatic amine curing agent composition was discovered and the present invention was achieved.

That is, the present invention provides a curing agent composition containing component (A): aromatic amine, component (B): salicylic acid, and component (C): hydroxyl group-containing aromatic solvent, based on 100 parts by mass of component (A). This is a curing agent composition containing 50 to 200 parts by mass of component (B).

The present invention also provides an epoxy resin composition containing the above curing agent composition and epoxy resin, and a cured product thereof.

The effect of the present invention is that even if a large amount of highly crystalline salicylic acid is added, it does not crystallize during storage, so that the curing agent composition has excellent storage stability. The curing agent composition of the present invention has an excellent curing speed compared to epoxy resins, and can provide a cured product that can withstand even severe corrosive environments. Therefore, it can be used in a wide range of fields, including structures such as bridges that require corrosion resistance and chemical resistance, road repair materials, and paints for the exterior walls and floors of buildings.

Examples of the aromatic amine that is component (A) used in the present invention include diethyltoluenediamine, diaminodiphenylmethane, dimethylthiotoluenediamine, 1-methyl-3,5-diethyl-2,4-diaminobenzene. , 1-methyl-3,5-diethyl-2,6-diaminobenzene, 1,3,5-triethyl-2,6-diaminobenzene, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4, 4'-Diamino-3,3'-dimethyldiphenylmethane, 3,5,3',5'-tetramethyl-4,4'-diaminodiphenylmethane, 4,4'-methylenebis[N-(1-methylpropyl)aniline ], 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 4-methyl-9,9-bis (4-aminophenyl)fluorene, 4-chloro-9,9-bis(4-aminophenyl)fluorene, 2-ethyl-9,9-bis(4-aminophenyl)fluorene, 2-iodo-9,9- Bis(4-aminophenyl)fluorene, 3-bromo-9,9-bis(4-aminophenyl)fluorene, 9-(4-methylaminophenyl)-9-(4-ethylaminophenyl)fluorene, 1-chloro -9,9-bis(4-aminophenyl)fluorene, 2-methyl-9,9-bis(4-aminophenyl)fluorene, 2,6-dimethyl-9,9-bis(4-aminophenyl)fluorene, 1,5-dimethyl-9,9-bis(4-aminophenyl)fluorene, 2-fluoro-9,9-bis(4-aminophenyl)fluorene, 1,2,3,4,5,6,7, 8-octafluoro-9,9-bis(4-aminophenyl)fluorene, 2,7-dinitro-9,9-bis(4-aminophenyl)fluorene, 2-chloro-4-methyl-9,9-bis (4-aminophenyl)fluorene, 2,7-dichloro-9,9-bis(4-aminophenyl)fluorene, 2-acetyl-9,9-bis(4-aminophenyl)fluorene, 2-methyl-9, 9-bis(4-methylaminophenyl)fluorene, 2-chloro-9,9-bis(4-ethylaminophenyl)fluorene, 2-t-butyl-9,9-bis(4-methylaminophenyl)fluorene, Examples include 4-chloro-o-phenylenediamine. Further, modified products of these amines may also be used. Examples of methods for modifying amines include dehydration condensation with carboxylic acids, addition reactions with epoxy resins, addition reactions with isocyanates, Michael addition reactions, Mannich reactions, condensation reactions with urea, and condensation reactions with ketones. These can be used alone or in combination in any proportion.

Preferred examples of component (A) include compounds represented by the following general formula (1).

(R ¹ in formula (1) each independently represents an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a thioalkyl group having 1 to 6 carbon atoms. n in formula (1) is a number of 2 or more and 4 or less.) A hydrogen atom is bonded to a bond on the ring that is not bonded to R ¹ or an amino group (hereinafter referred to as The same applies to equation (2) and subsequent equations).

Examples of the alkoxy group having 1 to 6 carbon atoms represented by R ¹ include methoxy group, ethoxy group, etc., and those having 1 to 2 carbon atoms are particularly preferred.
The thioalkyl group represented by R ¹ above includes a methylthio group, an ethylthio group, a propanthio group, etc., and those having 1 to 2 carbon atoms are particularly preferred.

Examples of the aliphatic hydrocarbon group having 1 to 6 carbon atoms represented by R ¹ above include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, and those having 1 to 2 carbon atoms are particularly preferred. preferable.

In formula (1), a compound in which the two amino groups on the benzene ring are in meta or para positions with respect to each other is more preferred. Further, as the compound of the above general formula (1), a compound having a total of three aliphatic hydrocarbon groups, an alkoxy group, and a thioalkyl group is particularly preferable because it has excellent curability. A group containing three group hydrocarbon groups is preferred. Compounds containing two or three ethyl groups are also particularly preferred since they have excellent curability. Among the aromatic amines, diethyltoluenediamine, 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene and 1,3, Mononuclear aromatic amines selected from 5-triethyl-2,6-diaminobenzene are preferred because they exhibit particularly excellent curability when combined with salicylic acid.

As the salicylic acid which is component (B) used in the present invention, commercially available salicylic acid can be used.

The hydroxyl group-containing aromatic solvent that is component (C) used in the present invention is a compound that has an aromatic ring structure and a hydroxyl group in its molecule. An example of the hydroxyl group-containing aromatic solvent is a compound represented by the following general formula (2).

(Ar in formula (2) represents an aromatic ring. R ⁷ in formula (2) is each independently a group represented by the following formula (3) or an aliphatic ring having 1 to 20 carbon atoms. Represents a hydrocarbon group. v in formula (2) is an integer greater than or equal to 0 and represents the number obtained by subtracting 1 from the number of bonds that ring Ar can take. L in formula (2) directly (represents a bond or a divalent hydrocarbon group)

(Each R ⁴ is independently a halogen atom, a methyl group, or a methoxy group, and m is a number from 0 to 5.) Examples of the halogen atom include a fluorine atom, a bromine atom, a chlorine atom, and an iodine atom. It will be done.

The aromatic ring Ar in the above general formula (2) can be a hydrocarbon ring or a heterocycle.
Examples of the hydrocarbon ring that is an aromatic ring include a benzene ring and a naphthalene ring.
The aromatic heterocycle may be a five-membered ring or a six-membered ring. Examples of the five-membered heterocycle include furan, thiophene, pyrrole, and pyrrolidine. Examples of the six-membered heterocycle include piperidine, piperazine, morpholine, thiomorpholine, and pyridine.

Examples of the aliphatic hydrocarbon group having 1 to 20 carbon atoms represented by R ⁷ in the above general formula (2) include alkyl groups such as methyl group, ethyl group, propyl group, and butyl group.

The divalent hydrocarbon group represented by L in the above general formula (2) includes alkylene groups having 1 to 8 carbon atoms such as methylene group, ethylene group, trimethylene group, and tetramethylene group.
The methylene chain in the alkylene group having 1 to 8 carbon atoms may be replaced by -O-, -S-, -CO- or -C=C-, and the hydrogen atom of the methylene chain is replaced by a halogen atom, hydroxy may be substituted with a group, a cyano group, an ester group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. In this case, the number of carbon atoms in the hydrocarbon group defines the number of carbon atoms after the methylene group is substituted.
In formula (2), the aromatic ring or heterocycle and the hydroxy group may be bonded directly to each other, may be bonded through a methylene group, or may be bonded through an ethylene group. There is also.

Specific examples of the hydroxyl group-containing aromatic solvent as component (C) include phenol, cresol, xylenol, ethylphenol, isopropylphenol, p-tert-butylphenol, p-tert-octylphenol, nonylphenol, dinonylphenol, and naphthol. , styrenated phenol, benzyl alcohol, furfuryl alcohol, phenethyl alcohol and the like. By using the hydroxyl group-containing aromatic solvent as component (C), crystallization of salicylic acid can be suppressed.
Among these hydroxyl group-containing aromatic solvents, styrenated phenol, benzyl alcohol, furfuryl alcohol, and the like are preferred because they can provide a curing agent composition with excellent storage stability.

In the curing agent composition of the present invention, the amount of salicylic acid as the component (B) is 50 to 200 parts by mass, preferably 75 to 150 parts by mass, relative to 100 parts by mass of the aromatic amine as the component (A). Department. If the amount is less than 50 parts by mass, the storage stability such as the appearance stability of the curing agent composition may be reduced, and if it is used in excess of 200 parts by mass, the curability of the curing agent composition may be reduced.
The amount of the hydroxyl group-containing aromatic solvent as component (C) is 10 to 200 parts by weight, preferably 25 to 150 parts by weight, per 100 parts by weight of component (B). By using 10 parts by mass or more of the hydroxyl group-containing aromatic solvent as component (C), it is possible to prevent a decrease in appearance stability, and by using 200 parts by mass or less, a decrease in curability can be prevented.

From the viewpoint that it is easier to achieve both appearance stability and curability, the total amount of components other than component (A), component (B) and component (C) in the curing agent composition of the present invention is as follows: The content is preferably 50% by mass or less, more preferably 10% by mass or less.

In addition, from the viewpoint of easier achieving both appearance stability and curability, the amount of component (C) relative to 100 parts by mass of component (A) is preferably 5 parts by mass or more and less than 500 parts by mass, and 10 parts by mass. More preferably, the amount is less than 300 parts by mass.

The curing agent composition of the present invention can be combined with a known epoxy resin to provide an epoxy resin composition.

Known epoxy resins include, for example, polyglycidyl ether compounds of mononuclear polyhydric phenol compounds such as hydroquinone, resorcinol, pyrocatechol, and phloroglucinol; dihydroxynaphthalene, biphenol, methylene bisphenol (bisphenol F), and methylene bis (orthocresol). ), ethylidene bisphenol, isopropylidene bisphenol (bisphenol A), isopropylidene bis (orthocresol), tetrabromobisphenol A, 1,3-bis(4-hydroxycumylbenzene), 1,4-bis(4-hydroxycumylbenzene), milbenzene), 1,1,3-tris(4-hydroxyphenyl)butane, 1,1,2,2-tetra(4-hydroxyphenyl)ethane, thiobisphenol, sulfobisphenol, oxybisphenol, phenol novolac, orthocresol Polyglycidyl ether compounds of polynuclear polyhydric phenol compounds such as novolak, ethylphenol novolak, butylphenol novolak, octylphenol novolak, resorcinol novolak, terpene phenol; ethylene glycol, propylene glycol, butylene glycol, hexanediol, polyethylene glycol, polypropylene glycol, thioglycol , dicyclopentadiene dimethanol, 2,2-bis(4-hydroxycyclohexyl)propane (hydrogenated bisphenol A), glycerin, trimethylolpropane, pentaerythritol, sorbitol, and polyhydric alcohol compounds such as bisphenol A-alkylene oxide adducts. Polyglycidyl ether compounds; maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, trimer acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid Homopolymers or copolymers of acids, glycidyl ester compounds of aliphatic, aromatic or alicyclic polybasic acids such as trimesic acid, pyromellitic acid, tetrahydrophthalic acid, endomethylenetetrahydrophthalic acid, and glycidyl methacrylate; N, N-diglycidylaniline, bis(4-(N-methyl-N-glycidylamino)phenyl)methane, diglycidyl orthotoluidine, N,N-bis(2,3-epoxypropyl)-4-(2,3- epoxypropoxy)-2-methylaniline, N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropoxy)aniline, N,N,N',N'-tetra(2,3 Epoxy compounds having a glycidylamino group such as -epoxypropyl)-4,4-diaminodiphenylmethane; vinylcyclohexene diepoxide, cyclopentanediene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3 , 4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexanecarboxylate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate and other epoxidized products of cyclic olefin compounds; epoxidized polybutadiene, epoxidized styrene- Examples include epoxidized conjugated diene polymers such as butadiene copolymers; heterocyclic compounds such as triglycidyl isocyanurate. In addition, these epoxy resins are those that are internally crosslinked with a prepolymer of terminal isocyanates, or those that have a high molecular weight with polyvalent active hydrogen compounds (polyhydric phenols, polyamines, carbonyl group-containing compounds, polyphosphate esters, etc.). But that's fine.
These epoxy resins may be used alone or in combination of two or more.

The epoxy resin composition of the present invention contains a curing agent composition containing the component (A), the component (B), and the component (C) as well as other commonly known epoxy resin curing agents (hereinafter referred to as "other"). (referred to as "hardening agent") can be used in combination. Examples of the other curing agents include phenolic curing agents, amine curing agents (excluding aromatic amines as component (A)), and the like.

The preferred usage amount of the epoxy resin and the curing agent composition (preferably the curing agent composition of the invention) in the epoxy resin composition of the present invention is 1 equivalent of the epoxy group in the epoxy resin (using a diluent containing an epoxy group). The amount is such that the active hydrogen equivalent of the curing agent composition (including other curing agents, if any) is 0.8 to 1.2 equivalents.

Examples of the phenolic curing agent include phenol novolak resin, cresol novolak resin, aromatic hydrocarbon formaldehyde resin modified phenol resin, dicyclopentadiene phenol addition type resin, phenol aralkyl resin (Zyrock resin), naphthol aralkyl resin, and trisphenyl resin. Roll methane resin, tetraphenylolethane resin, naphthol novolak resin, naphthol-phenol co-condensed novolak resin, naphthol-cresol co-condensed novolak resin, biphenyl-modified phenol resin (polyhydric phenol compound in which phenol nuclei are linked by bismethylene groups), Biphenyl-modified naphthol resin (a polyvalent naphthol compound in which the phenol nucleus is linked with a bismethylene group), aminotriazine-modified phenol resin (a compound that has a phenol skeleton, a triazine ring, and a primary amino group in its molecular structure), and alkoxy group-containing Examples include polyhydric phenol compounds such as aromatic ring-modified novolak resin (a polyhydric phenol compound in which a phenol nucleus and an alkoxy group-containing aromatic ring are linked with formaldehyde).

Examples of the amine curing agent include alkylene diamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,3-diaminobutane, 1,4-diaminobutane, hexamethylene diamine, and metaxylene diamine. Diamines; polyalkylpolyamines such as diethylenetriamine, triethylenetriamine and tetraethylenepentamine; 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 1,3-diaminomethylcyclohexane, 1,2-diaminocyclohexane, 1 ,4-diamino-3,6-diethylcyclohexane, 4,4'-diaminodicyclohexylmethane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 4,4'-diaminodicyclohexyl Alicyclic polyamines such as propane, bis(4-aminocyclohexyl)sulfone, 4,4'-diaminodicyclohexyl ether, 2,2'-dimethyl-4,4'-diaminodicyclohexylmethane, isophoronediamine and norbornenediamine; N , N-dimethylaminoethylamine, N,N-diethylaminoethylamine, N,N-diisopropylaminoethylamine, N,N-diallylaminoethylamine, N,N-benzylmethylaminoethylamine, N,N-dibenzylaminoethylamine, N, N-cyclohexylmethylaminoethylamine, N,N-dicyclohexylaminoethylamine, N-(2-aminoethyl)pyrrolidine, N-(2-aminoethyl)piperidine, N-(2-aminoethyl)morpholine, N-(2- aminoethyl)piperazine, N-(2-aminoethyl)-N'-methylpiperazine, N,N-dimethylaminopropylamine, N,N-diethylaminopropylamine, N,N-diisopropylaminopropylamine, N,N- Diallylaminopropylamine, N,N-benzylmethylaminopropylamine, N,N-dibenzylaminopropylamine, N,N-cyclohexylmethylaminopropylamine, N,N-dicyclohexylaminopropylamine, N-(3-amino 4 -(N,N-dimethylamino)benzylamine, 4-(N,N-diethylamino)benzylamine, 4-(N,N-diisopropylamino)benzylamine, N,N,-dimethylisophoronediamine, N,N- Dimethylbisaminocyclohexane, N,N,N'-trimethylethylenediamine, N'-ethyl-N,N-dimethylethylenediamine, N,N,N'-triethylethylenediamine, N'-ethyl-N,N-dimethylpropanediamine, N'-ethyl-N,N-dibenzylaminopropylamine, etc.; N,N-(bisaminopropyl)-N-methylamine, N,N-bisaminopropylethylamine, N,N-bisaminopropylpropylamine, N,N-bisaminopropylbutylamine, N,N-bisaminopropylpentylamine, N,N-bisaminopropylhexylamine, N,N-bisaminopropyl-2-ethylhexylamine, N,N-bisaminopropylcyclohexyl Amine, N,N-bisaminopropylbenzylamine, N,N-bisaminopropylallylamine, bis[3-(N,N-dimethylaminopropyl)]amine, bis[3-(N,N-diethylaminopropyl)] Amine, bis[3-(N,N-diisopropylaminopropyl)]amine, bis[3-(N,N-dibutylaminopropyl)]amine, etc.; oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide , dibasic acid dihydrazides such as adipic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide and phthalic acid dihydrazide; guanidine compounds such as dicyandiamide, benzoguanamine and acetoguanamine; and melamine.

Furthermore, a modified amine curing agent obtained by modifying the above-mentioned amines can also be used. Modification methods include dehydration condensation with carboxylic acids, addition reactions with epoxy compounds, addition reactions with isocyanate compounds, Michael addition reactions, Mannich reactions, condensation reactions with urea, and condensation reactions with ketones.

Examples of carboxylic acids that can be used to modify the amines include maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, and trimer acid. , aliphatic, aromatic or alicyclic polybasic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid and endomethylenetetrahydrophthalic acid, etc. can be mentioned.

Examples of epoxy compounds that can be used to modify the amines include the epoxy compounds exemplified as the above-mentioned known epoxy resins.

Examples of isocyanate compounds that can be used to modify the amines include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, phenylene diisocyanate, xylylene diisocyanate, Aromatics such as tetramethylxylylene diisocyanate, 1,5-naphthylene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, dianisidine diisocyanate and tetramethylxylylene diisocyanate Diisocyanates; cycloaliphatic diisocyanates such as isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, trans-1,4-cyclohexyl diisocyanate and norbornene diisocyanate; tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4 and/or aliphatic diisocyanates such as (2,4,4)-trimethylhexamethylene diisocyanate and lysine diisocyanate; isocyanurate trimers, biuret trimers, and trimethylolpropane adducts of the above-mentioned diisocyanates; triphenyl Examples include methane triisocyanate, 1-methylbenzole-2,4,6-triisocyanate, and dimethyltriphenylmethane tetraisocyanate. Furthermore, these isocyanate compounds can also be used in the form of modified products such as carbodiimide modification, isocyanurate modification, biuret modification, etc., and can also be used in the form of blocked isocyanates blocked with various blocking agents.

A curing accelerator can be used in combination with the epoxy resin composition of the present invention, if necessary. Examples of the curing accelerator include phosphines such as triphenylphosphine; phosphonium salts such as tetraphenylphosphonium bromide; amines such as benzyldimethylamine and 2,4,6-tris(dimethylaminomethyl)phenol; trimethylammonium Quaternary ammonium salts such as chloride; 3-(p-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-phenyl-1,1-dimethylurea , ureas such as isophorone diisocyanate-dimethylurea and tolylene diisocyanate-dimethylurea; complex compounds of boron trifluoride and amines, and complex compounds of boron trifluoride and ether compounds. These curing accelerators may be used alone or in combination of two or more types. The content of the curing accelerator is not particularly limited and can be appropriately set depending on the use of the curable resin composition.

In the epoxy resin composition of the present invention, a reactive diluent may be used in combination to adjust the viscosity to a desired value. Examples of such reactive diluents include n-butyl glycidyl ether, C ₁₂ -C ₁₄ alkyl glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, styrene oxide, phenyl glycidyl ether, cresyl glycidyl ether, Examples include p-sec-butylphenyl glycidyl ether, t-butylphenyl glycidyl ether, glycidyl methacrylate, and tertiary carboxylic acid glycidyl ester.

The epoxy resin composition of the present invention may further contain additives, if necessary. Examples of the additives include silane coupling agents, non-reactive diluents (plasticizers) such as dioctyl phthalate, dibutyl phthalate, benzyl alcohol, and coal tar; pigments; candelilla wax, carnauba wax, wood wax, Lubricants such as privet wax, beeswax, lanolin, spermaceti, montan wax, petroleum wax, fatty acid wax, fatty acid ester, fatty acid ether, aromatic ester, aromatic ether; thickener; thixotropic agent; antioxidant; photostabilizer UV absorbers; flame retardants; antifoaming agents; and rust preventives.

The epoxy resin composition of the present invention can be used in a wide range of applications such as various paints, various adhesives, and various molded products, but due to its properties, it can be particularly preferably used as a repair material for steel structures, concrete structures, etc. .

The present invention will be described in more detail below based on examples. However, the present invention is not limited to these Examples in any way.

[Example 1]
435.5 g of Etacure 100 Plus (manufactured by Mitsui Chemicals Fine Co., Ltd.; diethyltoluenediamine), 242 g of benzyl alcohol, and 322.5 g of salicylic acid were placed in a 2 L flask and mixed at 90 to 100°C for 2 hours to produce curing agent composition A1. did. In addition, in the following examples, when salicylic acid was not dissolved under these mixing conditions, mixing was extended until it was dissolved.

[Example 2]
A curing agent composition A2 was produced in the same manner as in Example 1 except that the content of salicylic acid was 452 g.

[Example 3]
A curing agent composition A3 was produced in the same manner as in Example 1 except that the content of salicylic acid was 554 g.

[Example 4]
A curing agent composition A4 was produced in the same manner as in Example 1 except that benzyl alcohol was changed to furfuryl alcohol.

[Comparative example 1]
A curing agent composition B1 was produced in the same manner as in Example 1 except that toluene was used instead of benzyl alcohol.

[Comparative example 2]
A curing agent composition B2 was produced in the same manner as in Example 1 except that benzyl alcohol was replaced with acetone.

[Appearance stability]
The curing agent compositions obtained in the Examples and Comparative Examples were placed in glass bottles and left at room temperature for one month. Visual evaluation was performed as follows. These results are shown in Table 1.
○: No sedimentation.
×: Sediment was confirmed.

[Examples 5 to 8, Comparative Examples 3 and 4]
850 parts by mass of ADEKA RIN EP-4100 (manufactured by ADEKA Corporation; bisphenol A type epoxy resin) and 150 parts by mass of ADEKA Glycilol ED-523T (manufactured by ADEKA Corporation; neopentyl glycol diglycidyl ether) at 50 to 80°C. The mixture obtained by kneading for 1 hour was used as the main ingredient. As shown in Table 2, the curing agent compositions obtained in the above Examples and Comparative Examples were used with respect to 100 parts by mass of the main resin, and the epoxy equivalent in the main resin and the active hydrogen equivalent in the curing agent composition were 1:1. Epoxy resin compositions were obtained using the following formulations. The following curing tests 1 and 2 were conducted using the obtained epoxy resin composition.

[Curing test 1]
If you put 50g of an epoxy resin composition in a paper cup and mix it at room temperature (22℃) while stirring it in a circular motion with a stirring rod and then lifting the stirring rod and pulling it apart, the time until the stringiness disappears ( minutes) was measured.

[Curing test 2]
4 g of the epoxy resin composition was applied onto a glass plate, and after being left at room temperature (22° C.) for 18 hours, the condition of the nails standing was evaluated according to the following criteria.
○: No claw marks remained.
×: Claw marks remained.

As can be seen from Table 1, the curing agent composition of the present invention has excellent appearance stability. Further, as can be seen from Table 2, the epoxy resin composition obtained by combining the curing agent composition of the present invention and an epoxy resin has excellent curability.

The curing agent composition of the present invention has excellent storage stability such as appearance stability, and the epoxy resin composition obtained by combining this with an epoxy resin has excellent curability. It can be used for adhesives and various molded products, and is particularly suitable for use as a corrosion-resistant repair material for metals, concrete, etc.

Claims (7)

A curing agent composition containing component (A): aromatic amine, component (B): salicylic acid, and component (C): hydroxyl group-containing aromatic solvent, wherein (B) is added to 100 parts by mass of component (A). A curing agent composition containing 50 parts by mass or more and 200 parts by mass or less. The curing agent composition according to claim 1, wherein the aromatic amine as component (A) is a compound represented by the following formula (1).
(R ¹ in formula (1) each independently represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a thioalkyl group having 1 to 4 carbon atoms. n in formula (1) is a number from 2 to 4.) The aromatic amine that is component (A) is diethyltoluenediamine, 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene and 1 , 3,5-triethyl-2,6-diaminobenzene. The curing agent composition according to any one of claims 1 to 3, wherein the hydroxyl group-containing aromatic solvent as component (C) is at least one selected from styrenated phenol, benzyl alcohol, and furfuryl alcohol. thing. The curing agent composition according to any one of claims 1 to 4, wherein the content of component (C) is 10 parts by mass or more and 200 parts by mass or less, based on 100 parts by mass of component (B). An epoxy resin composition comprising the curing agent composition according to any one of claims 1 to 5 and an epoxy resin. A cured product obtained by curing the epoxy resin composition according to claim 6.