Curing Agent Composition for Epoxy Resin, Epoxy Resin Composition, and Coating

Abstract

The present invention provides an epoxy resin curing agent composition, an epoxy resin composition containing the epoxy resin curing agent composition, and a coating, wherein the epoxy resin curing agent composition comprises: a component (A) which is a compound represented by the following general formula (1); and a component (B) which is at least one selected from the group consisting of compounds represented by the following general formula (2) and general formula (3), wherein the mass ratio of the component (A) to the component (B) is 7:3 to 9:1. (In the formula (1), R 1 and R 2 Each independently represents a hydrogen atom or a methyl group, X 1 ~X 3 Each independently represents a residue obtained by removing two amino groups from a polyamine compound, and n represents an integer from 0 to 10. (In formula (2), X 4 represents a residue formed by removing two amino groups from a polyamine compound. )(In formula (3), x represents an integer from 1 to 6, y represents an integer from 1 to 40, and z represents an integer from 1 to 6.)#imgabs0#

Description

Technical Field

[0001] The present invention relates to an epoxy resin curing agent composition, an epoxy resin composition, and a coating. More specifically, the present invention relates to an epoxy resin curing agent composition comprising two or more amine compounds having a specific skeleton, an epoxy resin composition comprising the epoxy resin curing agent composition, and a coating comprising the epoxy resin composition. Background Art

[0002] Epoxy resins exhibit excellent properties when used as adhesives, coatings, electrical insulation materials, and civil engineering and construction materials. Due to their excellent water resistance, chemical resistance, and corrosion resistance, they are widely used in coatings for automobiles, railway vehicles, buildings, ships, electrical equipment, and for coating the insides of beverage tanks.

[0003] Epoxy resins and curing agents used in coatings have traditionally used solvents to reduce viscosity for workability reasons. However, in recent years, environmental concerns have led to efforts to minimize the use of volatile solvents such as toluene and xylene used to dilute resins, leading to a shift from solvent-based to water-based coatings.

[0004] As for epoxy resins for water-based coatings, water-based epoxy resins are used, which are formed by dispersing or emulsifying epoxy resins in water. As a curing agent for curing the epoxy resin in the water-based epoxy resin, from the perspective of compatibility and reactivity with the water-based epoxy resin, a water-soluble curing agent or a curing agent dispersed or emulsified in water is preferred. As a curing agent suitable for water-based epoxy resins, for example, Patent Document 1 discloses a modified amine formed by reacting polyamines with methyl acrylate. This modified amine has an amide bond and good compatibility with water, but when using this modified amine alone to cure the epoxy resin, there are problems with the water resistance of the cured product. In addition, when other amine compounds are used in combination with this modified amine to improve the water resistance of the cured product, turbidity is generated in the curing agent composition due to the combined amine compounds, or the amine compounds crystallize, etc., and the compatibility of the amine compounds used in the curing agent composition is insufficient, which has problems with the storage stability of the curing agent composition and the workability when used as a curing agent composition.

[0005] Furthermore, Patent Document 2 discloses a water-based epoxy resin curing agent comprising a reaction composition containing a reaction product of styrene and an amine compound. While this curing agent exhibits good compatibility with water-based epoxy resins, the resulting epoxy cured product has problems with water resistance and corrosion resistance.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-70125

[0009] Patent Document 2: International Publication No. 2018 / 096868 Summary of the Invention

[0010] Problems to be solved by the invention

[0011] Therefore, the problem to be solved by the present invention is to provide a curing agent composition for epoxy resin, which maintains transparency, has good workability, has good compatibility with water-based epoxy resin, and has excellent water resistance and corrosion resistance in the cured product obtained by reacting with the epoxy resin.

[0012] Solutions for solving problems

[0013] The present inventors conducted intensive research and discovered that a curing agent composition containing specific amine compounds (A) and (B) within a specific mass ratio has transparency due to the good compatibility of the amine compounds used in components (A) and (B), and has good compatibility with a water-based epoxy resin. Furthermore, a cured product obtained by curing an epoxy resin composition containing the curing agent composition and the epoxy resin has excellent water resistance and corrosion resistance. Specifically, the present invention is a curing agent composition for an epoxy resin, comprising: component (A) being a compound represented by the following general formula (1); and component (B) being at least one selected from the group consisting of compounds represented by the following general formulas (2) and (3), wherein the mass ratio of component (A) to component (B) is 7:3 to 9:1.

[0014]

[0015] Where R 1 、R 2 Each independently represents a hydrogen atom or a methyl group, X 1 ~X 3 Each independently represents a residue obtained by removing two amino groups from a polyamine compound, and n represents an integer of 0 to 10.

[0016]

[0017] Where, X 4 It represents a residue formed by removing two amino groups from a polyamine compound.

[0018]

[0019] In the formula, x represents an integer of 1 to 6, y represents an integer of 1 to 40, and z represents an integer of 1 to 6.

[0020] Effects of the Invention

[0021] The curing agent composition of the present invention maintains transparency, exhibits good workability and compatibility with water-based epoxy resins, and the cured product obtained by curing the epoxy resin exhibits excellent water resistance and corrosion resistance. Therefore, it is useful as a curing agent composition for epoxy resins that reduces environmental impact. Furthermore, the epoxy resin composition obtained from the curing agent composition of the present invention and an epoxy resin is particularly useful as a coating for vehicles such as automobiles and railways, buildings, ships, and electrical equipment. DETAILED DESCRIPTION

[0022] <Curing agent composition>

[0023] The curing agent composition of the present invention, which can be used as a curing agent composition for an epoxy resin, contains the following components (A) and (B).

[0024] The component (A) is a compound represented by the following general formula (1).

[0025]

[0026] Where R 1 and R 2 Each independently represents a hydrogen atom or a methyl group, X 1 ~X 3 Each independently represents a residue obtained by removing two amino groups from a polyamine compound, and n represents an integer of 0 to 10.

[0027] From the viewpoint of easy production of the compound, R in the general formula (1) 1 and R 2 A hydrogen atom is preferred.

[0028] In the general formula (1), X 1 ~X 3Among the residues obtained by removing two amino groups from a polyamine compound, the polyamine compound is not particularly limited as long as it is a compound having two or more amino groups. For example, aliphatic polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyoxypropylenediamine, and polyoxypropylenetriamine; aliphatic polyamines containing aromatic rings such as m-xylylenediamine and p-xylylenediamine; isophoronediamine, menthanediamine, bis(4-amino-3-methyldicyclohexyl)methane, diaminodicyclohexylmethane, bis(aminomethyl)cyclohexane, N-aminoethylpiperazine, 3,9-bis(3-aminopropyl)-2-[4-amino-3-methyldicyclohexyl] ... , 4,8,10-tetraoxaspiro[5.5]undecane and other alicyclic polyamines; m-phenylenediamine, p-phenylenediamine, toluene-2,4-diamine, toluene-2,6-diamine, mesitylene-2,4-diamine, mesitylene-2,6-diamine, 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2,6-diamine and other mononuclear polyamines; aromatic polyamines such as benzyldiamine, 4,4-diaminodiphenylmethane, 2,5-naphthalenediamine, 2,6-naphthalenediamine; or modified polyamines such as epoxy addition modified products, amidation modified products, isocyanate modified products, Mannich modified products and the like obtained from these polyamine groups.

[0029] The number of carbon atoms in the polyamine compound is not particularly limited, but compounds having 2 to 30 carbon atoms are preferred, compounds having 2 to 20 carbon atoms are more preferred, and compounds having 4 to 12 carbon atoms are further preferred.

[0030] Among these polyamine compounds, from the viewpoint of water resistance and corrosion resistance of the cured product obtained using the curing agent composition of the present invention, aliphatic polyamines, aromatic ring-containing aliphatic polyamines, and alicyclic polyamines are preferred, m-xylylenediamine and isophorone diamine are more preferred, and m-xylylenediamine is particularly preferred. These compounds can be used alone or in combination. 1 ~X 3 All the same, can also be X 1 ~X 3 If any one of them is different, it can also be X 1 ~X 3 Although all of them are different, they are preferably all the same from the viewpoint of the water resistance and corrosion resistance of the obtained cured product and the ease of production of the compound represented by the general formula (1).

[0031] The compound represented by the general formula (1) wherein n is an integer of 0 to 10 is generally a mixture of compounds having different values of n. From the perspectives of lowering the viscosity of the curing agent composition, improving workability, and improving curability, the average value of n in the mixture is preferably 0 to 5, more preferably 0 to 3, further preferably 0 to 1, and particularly preferably 1.

[0032] It should be noted that when n is 2 to 10, there are multiple X 2 and R 2 They are optionally the same or different. From the viewpoint of facilitating the production of the compound, X is preferably 2 and R 2 The same respectively.

[0033] The compound represented by the general formula (1) can be produced by a known method. For example, it can be obtained by reacting the above-mentioned polyamine compound with (meth)acrylic acid, ethyl (meth)acrylate, or a halide of (meth)acrylic acid (hereinafter referred to as a (meth)acrylic acid compound). Here, (meth)acrylic acid refers to methacrylic acid or acrylic acid.

[0034] The average value of n can be determined by adjusting the molar ratio of the polyamine compound and the (meth)acrylic acid compound when reacting the polyamine compound. The molar ratio is preferably 0.1 to 0.9 mol, more preferably 0.2 to 0.8 mol, and even more preferably 0.5 to 0.75 mol per 1 mol of the polyamine compound.

[0035] Examples of the (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearic (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, and isobornyl (meth)acrylate.

[0036] Examples of the halogen in the (meth)acrylic acid halide include fluorine, chlorine, bromine, and iodine.

[0037] The (meth)acrylic acid compounds may be used alone or in combination of two or more. From the perspective of low cost and ease of production, the (meth)acrylic acid compounds are preferably used alone, more preferably (meth)acrylates, and particularly preferably methyl acrylate.

[0038] When the polyamine compound and (meth)acrylate are reacted, an alcohol derived from the (meth)acrylate is generated after the reaction. Therefore, it is preferable to remove the alcohol after the reaction.

[0039] Furthermore, the component (B) is at least one compound selected from the group consisting of compounds represented by the following general formula (2) and general formula (3).

[0040]

[0041] In the general formula (2), X 4It represents a residue formed by removing two amino groups from a polyamine compound.

[0042]

[0043] In the general formula (3), x represents an integer of 1 to 6, y represents an integer of 1 to 40, and z represents an integer of 1 to 6.

[0044] In the component (B), X in the general formula (2) 4 The polyamine compound in the residue obtained by removing two amino groups from the polyamine compound is not particularly limited as long as it has two or more amino groups, and examples thereof include the polyamine compounds in the above X 1 ~X 3 From the viewpoint of water resistance and corrosion resistance of the cured product obtained using the curing agent composition of the present invention, aliphatic polyamines, aromatic ring-containing aliphatic polyamines, and alicyclic polyamines are preferred, meta-xylylenediamine and isophoronediamine are more preferred, and meta-xylylenediamine is particularly preferred.

[0045] The compound represented by general formula (2) can be obtained by reacting styrene with the above-mentioned polyamine compound, optionally using a basic catalyst. The molar ratio of styrene to the polyamine compound during the reaction is preferably 0.5 to 1.5, more preferably 0.8 to 1.2, per 1 mol of the polyamine compound.

[0046] In the component (B), the compound in the general formula (3) wherein x represents a number from 1 to 6, y represents a number from 1 to 40, and z represents a number from 1 to 6 is usually a mixture of compounds having different values for x, y, and z. In the above mixture, from the viewpoint of the balance between the physical properties and water solubility of the cured product obtained using the curing agent composition, the average values of x and z are each independently preferably from 1 to 4. Furthermore, the average value of the sum of x + z is preferably from 3 to 5. From the viewpoint of the balance between the physical properties and water solubility of the cured product obtained using the curing agent composition, the average value of y is preferably from 5 to 15.

[0047] Among the components (B), compounds represented by the general formula (2) are preferred because they have better compatibility with the component (A) and can provide a curing agent composition having excellent transparency and storage condition.

[0048] As the component (B), commercially available products may be used, and examples thereof include Gaskamine 240 manufactured by Mitsubishi Gas Chemical Co., Ltd. and Jeffamine ED-600 manufactured by Huntsman.

[0049] The curing agent composition of the present invention is characterized in that the mass ratio of component (A) to component (B) is 7:3 to 9:1. From the perspective of further improving the performance of a cured product obtained using the curing agent composition, the mass ratio is more preferably 7.5:2.5 to 8.5:1.5. A mass ratio of component (A) to component (B) outside the range of 7:3 to 9:1 is not preferred because components (A) and (B) do not mix, resulting in turbidity, or the water resistance and corrosion resistance of the cured product are significantly reduced.

[0050] The curing agent composition of the present invention may also contain an amine curing agent other than the (A) component and the (B) component. As such an amine curing agent, there can be cited the above X 1 ~X 3 The polyamine compounds exemplified in the description of . Polyamine compounds that remain unreacted during the production of components (A) and (B) also qualify as the above-mentioned amine curing agent. When the curing agent composition of the present invention contains an amine curing agent other than components (A) and (B), the content of the amine curing agent other than components (A) and (B) is preferably 1 to 20 parts by mass, more preferably 1 to 10 parts by mass, relative to 100 parts by mass of the total mass of components (A) and (B), from the perspective of balancing the curability of the curing agent composition and maintaining a transparent appearance.

[0051] From the perspective of improving curability, the curing agent composition of the present invention may also contain a curing accelerator. Examples of curing accelerators include: tertiary amines such as trimethylamine, ethyldimethylamine, propyldimethylamine, N,N'-dimethylpiperazine, pyridine, picoline, 1,8-diazabicyclo(5,4,0)undecene-7 (DBU), benzyldimethylamine, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(dimethylaminomethyl)phenol; phenols such as butylphenol, phenol novolac, o-cresol novolac, p-cresol novolac, tert-butylphenol novolac, and dicyclopentadienecresol; p-toluenesulfonic acid, 1-aminopyrrolidino salt of thiocyanate (manufactured by Otsuka Chemical Co., Ltd.; NR-S), salicylic acid, and thiourea.

[0052] When the curing agent composition of the present invention contains the above-mentioned curing accelerator, the content of the curing accelerator is preferably 1 to 20 parts by mass, more preferably 1 to 10 parts by mass, relative to 100 parts by mass of the total mass of component (A) and component (B), from the viewpoint of balancing the curability of the curing agent composition and maintaining a transparent appearance.

[0053] The curing agent composition of the present invention can also be diluted with a solvent. For environmental reasons, it is best to avoid using such solvents whenever possible. If used, a low-volatility solvent is preferred to reduce the viscosity of the curing agent composition and improve workability. Examples of such solvents include alcohol solvents such as methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; ester solvents such as propylene glycol monomethyl ether acetate; nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; and sulfur-containing solvents such as dimethyl sulfoxide.

[0054] When the curing agent composition of the present invention contains a solvent, the content thereof is preferably 1 to 30% by mass, more preferably 5 to 25% by mass, relative to the total mass of the curing agent composition.

[0055] In the curing agent composition of the present invention, from the viewpoint of transparency, workability, and curability of the curing agent composition, the total content of component (A) and component (B) is preferably 60 to 100% by mass, more preferably 70 to 100% by mass, and even more preferably 75 to 100% by mass relative to the total amount of the curing agent composition.

[0056] The curing agent composition of the present invention may be produced by mixing the components (A) and (B) at once, along with any other amine curing agent, curing accelerator, solvent, etc. The production method is not particularly limited.

[0057] <Epoxy resin composition>

[0058] The epoxy resin composition of the present invention contains the above-mentioned curing agent composition and epoxy resin. Examples of epoxy resins include: polyglycidyl ether compounds of mononuclear polyphenol compounds such as hydroquinone, resorcinol, catechol, and phloroglucinol; dihydroxynaphthalene, biphenol, methylene bisphenol (bisphenol F), methylene bis(o-cresol), ethylene bisphenol, isopropylidene bisphenol (bisphenol A), isopropylidene bis(o-cresol), tetrabromobisphenol A, 1,3-bis(4-hydroxyisopropylphenylbenzene), 1,4-bis(4-hydroxyisopropylphenylbenzene), 1,1,3-tris(4-hydroxyphenyl)butane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, thiobisphenol, sulfobisphenol, oxybisphenol, phenol novolac, and o-cresol phenol. Polyglycidyl ether compounds of polynuclear polyphenol compounds such as formaldehyde varnish, ethylphenol novolac, butylphenol novolac, octylphenol novolac, resorcinol novolac, and terpene phenol; polyglycidyl ethers of polyols such as ethylene glycol, propylene glycol, butylene glycol, hexanediol, polyethylene glycol, thiodiglycol, dicyclopentadiene dimethanol, 2,2-bis(4-hydroxycyclohexylpropane (hydrogenated bisphenol A), glycerol, trimethylolpropane, pentaerythritol, sorbitol, and bisphenol A-alkylene oxide adducts; maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, trimer acid, and phthalic acid Glycidyl esters of aliphatic, aromatic or alicyclic polybasic acids such as isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid and endomethylenetetrahydrophthalic acid, and homopolymers or copolymers of glycidyl methacrylate; N,N-diglycidyl aniline, bis(4-(N-methyl-N-glycidylamino)phenyl)methane, diglycidyl o-toluidine, N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropyloxy)-2-methylaniline, N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropyloxy)-2-methylaniline Epoxides of cyclic olefin compounds such as vinylcyclohexene dioxide, dicyclopentadiene dioxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexylcarboxylate, and bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate; epoxidized conjugated diene polymers such as epoxidized polybutadiene and epoxidized styrene-butadiene copolymer; and heterocyclic compounds such as triglycidyl isocyanurate.

[0059] Among the epoxy resins listed above, polyglycidyl ether compounds of polynuclear polyphenol compounds and polyglycidyl ethers of polyols are preferred from the perspective of improving the water resistance and corrosion resistance of the resulting cured product, and bisphenol-type epoxy resins are more preferred. These epoxy resins can be used alone or in combination of two or more.

[0060] The epoxy resin may be used as is or dispersed or emulsified in water (hereinafter, the epoxy resin dispersed or emulsified in water is referred to as a water-based epoxy resin). Examples of methods for dispersing or emulsifying the epoxy resin in water include adding the epoxy resin to water, adding a surfactant, and dispersing or emulsifying the epoxy resin using a known method such as a disperser or homomixer.

[0061] Examples of the surfactant include common anionic and nonionic surfactants; cationic surfactants such as primary amine salts, secondary amine salts, tertiary amine salts, quaternary ammonium salts, and pyridinium salts; and amphoteric surfactants such as betaine-type, sulfate-type, and sulfonic acid-type surfactants.

[0062] Examples of the anionic surfactant include alkyl sulfates such as sodium lauryl sulfate, potassium lauryl sulfate, and ammonium lauryl sulfate; polyoxyethylene ether sulfates such as sodium lauryl polyethylene glycol ether sulfate and ammonium polyoxyethylene alkyl ether sulfate; alkyl sulfonates such as sodium sulforicinoleate, alkali metal salts of sulfonated paraffins, and ammonium salts of sulfonated paraffins; fatty acid salts such as sodium laurate, triethanolamine oleate, and triethanolamine rosinate; and alkylaryl sulfates such as sodium benzenesulfonate and alkali metal sulfates of basic phenol hydroxyethylene. Further examples include higher alkylnaphthalenesulfonates, naphthalenesulfonic acid formaldehyde condensates, dialkylsulfosuccinates, polyoxyethylene alkyl sulfates, polyoxyethylene alkylaryl sulfates, polyoxyethylene ether phosphates, polyoxyethylene alkyl ether acetates, N-acylamino acid salts, and N-acylmethyltaurates.

[0063] Examples of the nonionic surfactant include fatty acid partial esters of polyols such as sorbitan monolaurate and sorbitan monooleate; polyoxyethylene glycol fatty acid esters; and polyglycerol fatty acid esters. Further examples include ethylene oxide and / or propylene oxide adducts of alcohols having 1 to 18 carbon atoms, ethylene oxide and / or propylene oxide adducts of alkylphenols, and ethylene oxide and / or propylene oxide adducts of alkylene glycols and / or alkylenediamines.

[0064] Examples of the alcohol having 1 to 18 carbon atoms constituting the nonionic surfactant include methanol, ethanol, propanol, 2-propanol, butanol, 2-butanol, tert-butanol, amyl alcohol, isoamyl alcohol, tert-amyl alcohol, hexanol, octanol, decanol, lauryl alcohol, myristyl alcohol, palmityl alcohol, and stearyl alcohol.

[0065] Examples of the alkylphenols include phenol, methylphenol, 2,4-di-tert-butylphenol, 2,5-di-tert-butylphenol, 3,5-di-tert-butylphenol, 4-(1,3-tetramethylbutyl)phenol, 4-isooctylphenol, 4-nonylphenol, 4-tert-octylphenol, 4-dodecylphenol, 2-(3,5-dimethylheptyl)phenol, 4-(3,5-dimethylheptyl)phenol, naphthol, bisphenol A, and bisphenol F.

[0066] Examples of the alkylene glycol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2-methyl-1,3-propylene glycol, 2-butyl-2-ethyl-1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and 1,6-hexanediol.

[0067] The alkylenediamine is, for example, a compound in which the alcoholic hydroxyl group of the alkylene glycol described above is substituted with an amino group. As the ethylene oxide and propylene oxide adducts, both random adducts and block adducts can be used.

[0068] Examples of the cationic surfactant include lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, distearyldimethylammonium chloride, didecyldimethylammonium chloride, laurylbenzyldimethylammonium chloride, didecyldimethylammonium chloride, alkylpyridinium bromide, and imidazolinium laurate.

[0069] Examples of the amphoteric surfactant include betaine-type amphoteric surfactants such as coconut oil fatty acid amidopropyl dimethylacetic acid betaine, lauryl dimethyl amino acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxymethylimidazolinium betaine, lauryl hydroxysulfobetaine, lauryl hydroxyethylcarboxymethyl betaine, and metal salts of hydroxypropyl phosphate; amino acid-type amphoteric surfactants such as metal salts of β-laurylaminopropionic acid; sulfate-type amphoteric surfactants; and sulfonic acid-type amphoteric surfactants.

[0070] The content of the epoxy resin in the water-based epoxy resin is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, relative to the total mass of the water-based epoxy resin.

[0071] Commercially available water-based epoxy resins can be used, for example, jER series W2801, W2821R70, W3435R67, W8735R70, W1155R55, and W5654R45 manufactured by Mitsubishi Chemical Co., Ltd.; ADEKARESIN EM-101-50 manufactured by ADEKA Corporation; EPICLONEX A-8610 manufactured by DIC Corporation; Araldite series PZ3901, PZ3921, and PZ3961-1 manufactured by Huntsman; DER915 and DER917 manufactured by Olin; and EPIREZ series Resin 3520-WY-55 and Resin 6520-WH-53 manufactured by Hexion.

[0072] When the epoxy resin composition of the present invention contains a water-based epoxy resin, the water content in the epoxy resin composition is preferably 10 to 60% by mass, more preferably 15 to 50% by mass, from the viewpoint of both workability and reduced environmental load.

[0073] Regarding the blending ratio of the curing agent composition of the present invention and the epoxy resin in the epoxy resin composition of the present invention, the active hydrogen equivalent in the curing agent composition is preferably 0.4 to 2.0 equivalents, more preferably 0.5 to 1.5 equivalents, and even more preferably 0.6 to 1.0 equivalents per 1 equivalent of epoxy groups in the epoxy resin. If the active hydrogen equivalent in the curing agent composition per 1 equivalent of epoxy groups in the epoxy resin is less than 0.4 equivalents or more than 2.0 equivalents, the epoxy resin composition may not cure.

[0074] The epoxy resin composition of the present invention may be produced by mixing the curing agent composition and the water-based epoxy resin at once, and the production method is not particularly limited.

[0075] <Paint>

[0076] The coating of the present invention comprises the epoxy resin composition of the present invention, i.e., the curing agent composition of the present invention, and an epoxy resin as essential components. However, additives may be included as needed to improve the performance of the coating. Examples of such additives include inorganic fillers, wetting agents, dispersants, defoamers, viscosity modifiers, tackifiers, leveling agents, anti-sagging agents, pH adjusters, crosslinking agents, stabilizers, mildew inhibitors, antifreeze agents, film-forming aids, antioxidants, flash rust inhibitors, coupling agents, chelating agents, and wettability enhancers.

[0077] The coating of the present invention can be used directly as an epoxy resin composition comprising the curing agent composition of the present invention, an epoxy resin, and any additives. However, the coating can also be diluted with water, a solvent, or the like to improve workability. When the epoxy resin composition is diluted to form a coating, dilution with water is preferred from an environmental perspective. The combined mass of the curing agent composition and epoxy resin in the diluted form is preferably 10 to 50% by mass, more preferably 15 to 40% by mass, relative to the total mass of the coating.

[0078] The coating of the present invention is a coating that can protect a substrate such as metal, wood, plastic, stone, slate, concrete, mortar, etc. by being applied to the substrate. In addition, the coating of the present invention can also be used as an anti-corrosion coating to prevent corrosion of the substrate. In particular, when the coating of the present invention is used as an anti-corrosion coating for a substrate comprising metal, it is preferred that the coating contain an anti-rust pigment.

[0079] Examples of the rust-preventive pigment include zinc powder, flaky zinc powder, zinc alloy powder, zinc phosphate compounds, calcium phosphate compounds, aluminum phosphate compounds, magnesium phosphate compounds, zinc phosphite compounds, calcium phosphite compounds, aluminum phosphite compounds, strontium phosphite compounds, aluminum tripolyphosphate compounds, molybdate compounds, zinc cyanamide compounds, borate compounds, nitro compounds, and composite oxides. Among these, zinc-based rust-preventive pigments such as zinc powder, flaky zinc powder, zinc alloy powder, and zinc phosphate compounds are preferred due to their high rust-preventive properties.

[0080] The content of the rust-proof pigment is preferably 1 to 100 parts by mass, more preferably 5 to 90 parts by mass, and even more preferably 10 to 80 parts by mass, relative to 100 parts by mass of the total mass of the curing agent composition and the epoxy resin.

[0081] In the method for producing the coating of the present invention, the curing agent composition, epoxy resin, any additives, anti-rust pigment, water, solvent, etc. can be mixed at once, or the curing agent composition and epoxy resin can be diluted with water in advance and then the remaining ingredients are added. The production method is not limited.

[0082] It should be noted that among the additives and rust-proof pigments used in the coatings listed above, some may decompose and generate hydrogen gas when in contact with water for a long time. Therefore, when using these additives and rust-proof pigments in a water-containing system, such as when using a water-based epoxy resin as the epoxy resin, it is preferable to add them immediately before using the coating.

[0083] The curing agent composition of the present invention preferably contains substantially no water, as the aforementioned additives and rust-preventive pigments can be pre-added to the curing agent composition and stored, allowing for the coating to be produced by adding them all at once immediately before use. The ability to pre-prepare a curing agent composition containing the additives and rust-preventive pigments improves workability, facilitating ease of metering during coating production.

[0084] When the coating of the present invention is used as an anticorrosive coating, the coating method is not particularly limited, and known coating methods such as spraying, roller coating, brushing, trowel coating, and blade coating can be used. In addition, the dry film thickness formed by the above-mentioned anticorrosive coating is not particularly limited, and the range of 30 to 300 μm can be exemplified.

[0085] Example

[0086] Hereinafter, the present invention will be described in detail with reference to Examples. In the following Examples, etc., % is by mass unless otherwise specified.

[0087] <Curing agent composition>

[0088] ·(A)Ingredients

[0089] [Production Example 1]

[0090] 522.5 g of m-xylenediamine and 219.7 g of methyl acrylate were added to a 2 L glass flask and reacted at 90-100°C for 1 hour. The mixture was then heated to 150-160°C and the methanol generated during the reaction was removed under normal pressure and reduced pressure to obtain a curing agent A-1. The curing agent A-1 is the following compound: In the above general formula (1), X 1 ~X 3 The residue formed by removing two amino groups from m-phenylenediamine, R 1 and R 2 is a hydrogen atom, n is 0 to 3, and the average value of n is 1.0.

[0091] (B) ingredient

[0092] G-240: Gaskamine 240 (which is the reaction product of styrene and m-xylenediamine, where X in the above general formula (2) 4 A compound obtained by removing two amino groups from m-xylylenediamine, active hydrogen equivalent: 103 g / eq., manufactured by MITSUBISHI Gas Chemical Co., Ltd.

[0093] ED-600: Jeffamine ED-600 (a polyether polyamine in which x and z in the general formula (3) are 1 to 6, the average value of the sum of x and z is 3.6, y is 5 to 15, and the average value of y is 9, active hydrogen equivalent: 132 g / eq., manufactured by Huntsman).

[0094] Amine compounds or imine compounds other than components (A) and (B)

[0095] D-400: Jeffamine D-400 (polypropylene oxide addition type polyether polyamine, manufactured by Huntsman).

[0096] M-1000: Jeffamine M-1000 (polyethylene oxide-polypropylene oxide addition type polyether monoamine, manufactured by Huntsman).

[0097] EHC-30: ADEKA HARDENER EHC-30 (aromatic tertiary amine, manufactured by ADEKA Corporation).

[0098] P-1000: EPOMIN P-1000 (polyethyleneimine, manufactured by Nippon Catalyst Co., Ltd.).

[0099] [Examples 1 to 4, Comparative Examples 1 to 6]

[0100] According to the mixing ratio shown in Table 1, as Examples 1 to 4, curing agent A-1 as component (A) and an amine compound as component (B) were mixed in a mass ratio ranging from 7:3 to 9:1 to prepare curing agent compositions. Furthermore, as Comparative Examples 1 to 4, curing agent A-1 was mixed with an amine compound or imine compound other than components (A) and (B). As Comparative Examples 5 and 6, curing agent A-1 was mixed with an amine compound as component (B) at a mass ratio outside the above range to prepare curing agent compositions. The appearance of each curing agent composition was confirmed. Curing agent compositions with a transparent appearance were evaluated as acceptable, while curing agent compositions in which separation, crystallization, turbidity, etc. were observed were evaluated as unacceptable.

[0101] [Table 1]

[0102]

[0103] As can be seen from the results in Table 1, the curing agent compositions of Examples 1 to 4 showed excellent compatibility between the amine compounds used as component (A) and component (B), a transparent appearance, and good storage conditions. However, the curing agent compositions of Comparative Examples 1 to 6 showed separation, crystallization, and turbidity between the amine compounds or between the amine compound and the imine compound, resulting in problems with storage conditions and workability during use.

[0104] <Epoxy resin composition>

[0105] The epoxy resin composition of Example 5 was prepared as follows.

[0106] [Example 5]

[0107] To a 200 mL beaker, 64 g of curing agent A-1 (component (A)), 16 g of G-240 (component (B)), and 20 g of propylene glycol monomethyl ether (diluent) were added. The mixture was stirred for 5 minutes to prepare curing agent composition X. The theoretical active hydrogen equivalent of curing agent composition X is 110 g / eq.

[0108] ADEKA RESIN EM-101-50 (solid BPA-type epoxy resin emulsion, epoxy equivalent: 1075 g / eq., epoxy resin content 47% by mass, manufactured by ADEKA Co., Ltd.) as an epoxy resin was mixed with the above-mentioned curing agent composition X so that the ratio of the active hydrogen equivalent in the curing agent composition X to the epoxy equivalent in the epoxy resin (active hydrogen equivalent / epoxy equivalent) was 0.8 to prepare an epoxy resin composition.

[0109] [Comparative Example 7]

[0110] 70 g of Curing Agent A-1 and 30 g of water were added to a 200 mL beaker and stirred for 5 minutes to obtain Curing Agent Composition A-2. The theoretical active hydrogen equivalent of Curing Agent Composition A-2 is 121 g / eq. An epoxy resin composition was prepared in the same manner as in Example 5, except that Curing Agent Composition A-2 was used instead of Curing Agent Composition X.

[0111] [Comparative Example 8]

[0112] An epoxy resin composition was prepared in the same manner as in Example 5 except that G-240 (active hydrogen equivalent: 103 g / eq.) was used instead of the curing agent composition X.

[0113] [Comparative Example 9]

[0114] An epoxy resin composition was prepared in the same manner as in Example 5 except that ED-600 (active hydrogen equivalent: 132 g / eq.) was used instead of the curing agent composition X.

[0115] Each of the epoxy resin compositions obtained was evaluated for tack-free time (curability), pencil hardness, adhesion, water resistance, water absorption, and corrosion resistance according to the following methods. The results are shown in Table 2.

[0116] <Surface drying time>

[0117] After applying the epoxy resin composition to a thickness of 100 μm on a glass plate, the glass plate was stored at 25° C., and the time until the epoxy resin composition stopped adhering to the finger was measured.

[0118] Pencil hardness

[0119] An epoxy resin composition was applied to a steel plate (SPCC-SB) to a thickness of 100 μm and allowed to stand at 25°C for 4 days to dry and form a cured product. Then, in accordance with JIS K 5600-5-4, a pencil lead was placed in contact with the surface of the coating (cured product) at an angle of approximately 45°. While pressing firmly against the surface of the test coated plate without breaking the lead, the lead was moved forward at a uniform speed for approximately 10 mm. The pencil hardness was determined by measuring the hardest pencil that did not damage the coating.

[0120] Adhesion

[0121] An epoxy resin composition was applied to a steel plate (SPCC-SB) to a thickness of 100 μm. The composition was allowed to stand at 25°C for 4 days to dry and form a cured product. A cutter was then used to cut the coating (cured product) in a 25-square grid pattern, 2 mm wide. Adhesive tape was then applied to the surface, and the coating was allowed to stand for 5 minutes. The tape was then peeled off, and the number of squares removed from the 25 squares was counted.

[0122] Water resistance

[0123] The epoxy resin composition was applied to a glass plate to a thickness of 100 μm, allowed to stand at 25°C for 4 days to dry and form a cured product. The glass plate was then immersed in 25°C water for 1 day, and the appearance of the coating film (cured product) after immersion was examined. Coatings without whitening were considered acceptable, while those with whitening were considered unacceptable.

[0124] Water absorption rate

[0125] The epoxy resin composition was applied to a pre-weighed glass plate to a thickness of 100 μm. The composition was allowed to stand at 25°C for 4 days to dry and form a cured product. The glass plate (test piece) with the coating (cured product) was then weighed. The test piece was then immersed in 50°C water for 1 day, and any water droplets on the surface were wiped off and weighed. The water absorption was then calculated from the weighted values using the following formula.

[0126] [{(Weight of the test piece after immersion - Weighing value of the glass plate) / (Weight of the test piece before immersion - Weighing value of the glass plate)}×100] - 100 (%)

[0127] The closer the water absorption is to 0%, the better the result is. In addition, when the water absorption is negative, it is considered that the components in the cured product ooze out and the mass decreases.

[0128] Corrosion resistance

[0129] The epoxy resin composition was applied to a sandblasted steel plate (SS400) to a thickness of 100 μm. The film was allowed to stand at 25°C for 4 days to dry and form a cured product. The coating film (cured product) was then cross-sectioned. A salt spray test was then conducted at 35°C for 72 hours in accordance with JIS Z 2371. The formation of red rust on the coated surface was confirmed and evaluated as follows.

[0130] ○: Red rust is hardly observed except for the cross-cut portion.

[0131] Δ: Red rust was observed on a portion of the coated surface.

[0132] ×: Red rust was observed on the entire coated surface.

[0133] [Table 2]

[0134] Example 5 Comparative Example 7 Comparative Example 8 Comparative Example 9 Curing agent composition X A-2 G-240 ED-600 Surface drying time (hours) 2 2 2.5 6 Pencil hardness HB F HB B Adhesion (number of cells peeled off) 0 0 18 0 Water resistance qualified Unqualified Unqualified Unqualified Water absorption (%) 0.3 3.0 5.2 -1.9 Corrosion resistance ○ Δ Δ ×

[0135] As shown in the results in Table 2, the epoxy resin composition of Example 5, which used the curing agent composition of the present invention, was evaluated as good in all evaluations, including the water resistance and corrosion resistance of the cured product. The cured products of the epoxy resin compositions of Comparative Examples 7 to 9, which did not use the curing agent composition of the present invention, did not satisfy all evaluation criteria.

Claims

1. A curing agent composition for epoxy resin, comprising: Component (A) being a compound represented by the following general formula (1); and component (B) being at least one selected from the group consisting of compounds represented by the following general formula (2) and general formula (3), wherein the mass ratio of component (A) to component (B) is 7:3 to 9:1, Where R 1 、R 2 Each independently represents a hydrogen atom or a methyl group, X 1 ~X 3 Each independently represents a residue formed by removing two amino groups from a polyamine compound, and n represents an integer from 0 to 10. Where, X 4 It represents the residue formed by removing two amino groups from a polyamine compound. In the formula, x represents an integer of 1 to 6, y represents an integer of 1 to 40, and z represents an integer of 1 to 6.

2. The epoxy resin curing agent composition according to claim 1, wherein In the general formula (1), X 1 ~X 3 It is a residue formed by removing two amino groups from m-xylylenediamine.

3. The epoxy resin curing agent composition according to claim 1 or 2, wherein The component (B) is a compound represented by the general formula (2).

4. An epoxy resin composition comprising: The epoxy resin curing agent composition according to any one of claims 1 to 3; and an epoxy resin.

5. The epoxy resin composition according to claim 4, wherein The epoxy resin is a water-based epoxy resin dispersed or emulsified in water. 6 . A cured product obtained by curing the epoxy resin composition according to claim 4 .

7. A coating comprising the epoxy resin composition according to claim 4 or 5.

8. A method for preventing corrosion of a substrate, comprising applying the coating according to claim 7 to a substrate.

9. Use of a coating, which is use of the coating according to claim 7 for preventing corrosion of a substrate.

10. A method for improving the water resistance and corrosion resistance of a cured product, comprising adding the epoxy resin curing agent composition according to any one of claims 1 to 3 to an epoxy resin, The cured product is a cured product obtained by curing the epoxy resin.

11. Use of a curing agent composition for an epoxy resin, comprising: using the curing agent composition for an epoxy resin according to any one of claims 1 to 3 for improving the water resistance and corrosion resistance of a cured product obtained by curing an epoxy resin.

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