Epoxy resin curing agent, epoxy resin composition, and paint

Abstract

To provide an epoxy resin curing agent, an epoxy resin composition and a paint that cure fast, have low viscosity, and can form a paint film with high hardness.SOLUTION: An epoxy resin curing agent and an epoxy resin composition contain the following components (A) and (B): (A) a diamine represented by the general formula (1) in the figure, where m and n are each independently a number from 0 to 4, or a modified form thereof; and (B) a polyamine having a ring structure other than the component (A), or a modified form thereof. Also provided is a paint containing them.SELECTED DRAWING: None

Description

Technical field

[0001] The present invention relates to an epoxy resin curing agent, an epoxy resin composition, and a paint containing the same. [Background technology]

[0002] Various polyamine compounds are widely known as epoxy resin curing agents. Epoxy resin compositions using polyamine compounds as epoxy resin curing agents are used in the paint field, such as anticorrosion paints for ships, bridges, land and sea railway structures, lining, reinforcement and repair materials for concrete structures, flooring materials for buildings, It is also used in civil engineering and construction fields, such as water and sewage linings, paving materials, and adhesives.

[0003] Compounds obtained by modifying polyamines with epoxy compounds and the like (modified polyamines) are also known to be useful as epoxy resin curing agents. For example, Patent Document 1 describes a polyglycidyl ether of a polyphenol that is solid at room temperature and an alicyclic or It is disclosed that an adduct obtained by reacting alicycloaliphatic diprimary diamine at a predetermined ratio is suitable as a curing agent for epoxy resin. [Prior art documents] [Patent document]

[0004] [Patent Document 1] Special Publication No. 50-1600 [Summary of the invention] [Problem to be solved by the invention]

[0005] Modified polyamines may have higher viscosity and lower handling properties than unmodified polyamines, but Patent Document 1 discloses that trimethyl-hexamethylene diamine or the like is used to reduce the viscosity of the adduct. It is also stated that. Among the various uses of epoxy resin compositions, it is important for epoxy resin compositions for paints that the resulting paint film has good physical properties such as appearance, water resistance, and hardness. However, with the technique disclosed in Patent Document 1, there is room for improvement in obtaining a coating film with high hardness while suppressing a decrease in the curing speed and an increase in viscosity of the epoxy resin curing agent and the epoxy resin composition. An object of the present invention is to provide an epoxy resin curing agent, an epoxy resin composition, and a paint that cure quickly, have low viscosity, and can form a highly hard coating film. [Means to solve the problem]

[0006] The present inventors have discovered that an epoxy resin curing agent containing an alicyclic diamine having a predetermined structure or a modified product thereof and another polyamine having a ring structure or a modified product thereof can solve the above problems. That is, the present invention relates to the following. [1] An epoxy resin curing agent containing the following components (A) and (B). (A) Diamine represented by the following general formula (1) or a modified product thereof [ka] In formula (1), m and n are each independently a number from 0 to 4. (B) A polyamine having a ring structure other than the above component (A) or a modified product thereof [2] An epoxy resin composition containing an epoxy resin and the epoxy resin curing agent described in [1] above. [3] A paint containing the epoxy resin composition described in [2] above.

Effect of the invention

[0007] According to the present invention, it is possible to provide an epoxy resin curing agent, an epoxy resin composition, and a cured product thereof that cures quickly, has a low viscosity, and can form a highly hard coating film. [Details for carrying out the invention]

[0008] [Epoxy resin curing agent] The epoxy resin curing agent of the present invention contains the following component (A) and component (B). (A) Diamine represented by the following general formula (1) or a modified product thereof [ka] In formula (1), m and n are each independently a number from 0 to 4. (B) A polyamine having a ring structure other than the above component (A) or a modified product thereof By using the above-mentioned epoxy resin curing agent, it is possible to provide an epoxy resin composition that cures quickly, has a low viscosity, and can form a coating film with high hardness. Hereinafter, the epoxy resin curing agent of the present invention is also simply referred to as "the curing agent of the present invention."

[0009] The reason why the above effects are obtained by using the curing agent of the present invention in an epoxy resin composition is not clear, but it is thought to be as follows. By containing the component (A), the curing agent of the present invention can lower the viscosity, and when used in an epoxy resin composition, the hardening agent has high hardness in the coating film that is the cured product of the epoxy resin composition. is considered to be obtained. However, when component (A) is used alone as an epoxy resin curing agent, the curing speed tends to be slow, and there is room for improvement in this respect. Furthermore, as in the technique disclosed in Patent Document 1, when component (A) and a chain diamine such as trimethyl-hexamethylene diamine are used together in an epoxy resin curing agent, the curing rate and the epoxy resin composition There is a concern that the hardness of the coating film, which is a cured product, may decrease. In the present invention, by using an epoxy resin curing agent containing both component (A) and component (B), which is a polyamine having a ring structure or a modified product thereof, the low viscosity derived from component (A) can be improved. It is thought that the curing speed could be increased while maintaining the high hardness of the coating film.

[0010] <Component (A): Diamine represented by general formula (1) or modified product thereof> The epoxy resin curing agent of the present invention contains a diamine represented by the following general formula (1) or a modified product thereof as component (A). [ka] In formula (1), m and n are each independently a number from 0 to 4. In formula (1), m and n are preferably 0 to 3, more preferably 0 to 2, and even more preferably 0 or 1, from the viewpoint of fast curing properties, low viscosity properties, and improvement in the hardness of the coating film. . However, from the viewpoint of improving fast curing properties and low viscosity properties, in formula (1), the case where both m and n are 0 is preferably excluded. From the viewpoint of fast curing properties, low viscosity properties, and improvement in the hardness of the coating film, m in formula (1) is 0, and n is 1 to 4, preferably 1 to 3, more preferably 1 or 2, and even more preferably is 1.

[0011] Specific examples of the diamine represented by the general formula (1) include 1,2-diaminocyclopentane, 1,2-bis(aminomethyl)cyclopentane, 1,2-bis(aminoethyl)cyclopentane, 1, 2-bis(aminopropyl)cyclopentane, 1,2-bis(aminobutyl)cyclopentane, 2-aminomethylcyclopentylamine, 2-aminoethylcyclopentylamine, 2-aminopropylcyclopentylamine, 2-aminobutylcyclopentylamine, etc. Among these, one type or two or more types can be used. Among the above, from the viewpoint of fast curing properties, low viscosity properties, and improvement in the hardness of the coating film, the diamine represented by the general formula (1) is preferably 2-aminomethylcyclopentylamine, 2-aminoethylcyclopentylamine, At least one selected from the group consisting of 2-aminopropylcyclopentylamine and 2-aminobutylcyclopentylamine, more preferably at least one selected from the group consisting of 2-aminomethylcyclopentylamine and 2-aminoethylcyclopentylamine. species, more preferably 2-aminomethylcyclopentylamine.

[0012] Component (A) may be a diamine represented by the above general formula (1), or may be a modified product of the diamine. Specific examples of modified diamines represented by the general formula (1) include Mannich-modified products, epoxy-modified products, Michael adducts, Michael addition / polycondensates, and styrene-modified products of the diamine shown by the general formula (1). , modified polyamides, and the like. Among these, the modified diamine represented by the general formula (1) is preferably a modified form of the diamine represented by the general formula (1), from the viewpoint of fast curing, low viscosity, and improvement in the hardness of the coating film. Epoxy modified products are preferred. The epoxy-modified diamine represented by the general formula (1) is a reaction product of the diamine represented by the general formula (1) and an epoxy compound having at least one epoxy group. In addition, in this specification, the reaction product of the diamine represented by general formula (1) and the epoxy compound having at least one epoxy group is the product obtained by the reaction between the diamine and the epoxy compound. It means a reaction composition containing a reactant (adduct) of the diamine and the epoxy compound. Hereinafter, the epoxy-modified diamine represented by the general formula (1) is also simply referred to as "the epoxy-modified product."

[0013] The epoxy compound used in the epoxy modified product may be any compound having at least one epoxy group, and more preferably a compound having two or more epoxy groups. Specific examples of the epoxy compound include epichlorohydrin, butyl diglycidyl ether, neopentyl glycol diglycidyl ether, 1,3-propanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6- Polyfunctional epoxy resins with glycidylamino groups derived from hexanediol diglycidyl ether, biphenol diglycidyl ether, dihydroxynaphthalene diglycidyl ether, dihydroxyanthracene diglycidyl ether, triglycidyl isocyanurate, tetraglycidyl glycoluril, metaxylylene diamine , a polyfunctional epoxy resin having a glycidylamino group derived from 1,3-bis(aminomethyl)cyclohexane, a polyfunctional epoxy resin having a glycidylamino group derived from diaminodiphenylmethane, a glycidylamino group derived from para-aminophenol. and / or polyfunctional epoxy resins having glycidyloxy groups, polyfunctional epoxy resins having glycidyloxy groups derived from bisphenol A, polyfunctional epoxy resins having glycidyloxy groups derived from bisphenol F, polyfunctional epoxy resins having glycidyloxy groups derived from phenol novolacs, Examples thereof include a polyfunctional epoxy resin having a glycidyloxy group, and a polyfunctional epoxy resin having two or more glycidyloxy groups derived from resorcinol. These can be used alone or in combination of two or more. From the viewpoint of fast curing, low viscosity, and improvement in the hardness of the coating film, the epoxy compound is preferably a compound containing an aromatic ring or an alicyclic structure in the molecule, and more preferably a compound containing an aromatic ring in the molecule. Preferably, a polyfunctional epoxy resin having a glycidyloxy group derived from bisphenol A is even more preferable.

[0014] The epoxy modified product can be obtained by subjecting the diamine represented by general formula (1) and an epoxy compound to a ring-opening addition reaction using a known method. For example, a method may be used in which the diamine represented by the general formula (1) is charged into a reactor, and the epoxy compound is added thereto all at once or in portions by dropwise addition, heated, and reacted. The addition reaction is preferably carried out under an inert atmosphere such as nitrogen gas.

[0015] The amounts of the diamine represented by the general formula (1) and the epoxy compound to be charged are not particularly limited as long as the ratio is such that the resulting epoxy modified product contains an amino group having active hydrogen. From the viewpoint of expressing the function as a resin curing agent, in the addition reaction, it is preferable to use an excess amount of diamine with respect to the epoxy equivalent of the epoxy compound. Specifically, the number of active hydrogens in the diamine relative to the number of epoxy groups in the epoxy compound (number of active hydrogens in the diamine / number of epoxy groups in the epoxy compound) is preferably 50 / 1 to 4 / 1, more preferably 20 / 1. The diamine and epoxy compound are used in a ratio of 1 to 4 / 1.

[0016] The temperature and reaction time during the addition reaction can be selected as appropriate, but from the viewpoint of reaction rate, productivity, and prevention of decomposition of raw materials, the temperature during the addition reaction is preferably 50 to 150°C, more preferably 70 to 150°C. The temperature is 120℃. Further, the reaction time is preferably 0.5 to 12 hours, more preferably 1 to 6 hours after the addition of the epoxy compound is completed.

[0017] Component (A) preferably contains a modified diamine represented by the general formula (1) from the viewpoint of fast curing properties, low viscosity, and improvement in the hardness of the coating film. It is more preferable to contain an epoxy-modified diamine represented by: When component (A) contains an epoxy-modified product of the diamine represented by the general formula (1), the content of the epoxy-modified product in component (A) is determined to improve fast curing, low viscosity, and coating film. From the viewpoint of improving the hardness of Even more preferably it is 95% by mass or more and 100% by mass or less.

[0018] <Component (B): Polyamine having a ring structure other than component (A) or modified product thereof> The epoxy resin curing agent of the present invention contains, as component (B), a polyamine having a ring structure or a modified product thereof other than the component (A). The polyamine is a compound (unmodified) having at least one ring structure and at least two amino groups in the molecule. The number of ring carbon atoms in the ring structure of the polyamine is preferably 5 to 20, more preferably 5 to 12, even more preferably 5 to 8, even more preferably 5 to 6, from the viewpoint of ensuring low viscosity. Even more preferably, it is 6.

[0019] Examples of the ring structure that the polyamine has include an alicyclic structure, an aromatic ring, and a heterocyclic structure. Alicyclic structure means a ring structure derived from an alicyclic hydrocarbon. The alicyclic structure may be saturated or unsaturated, and may be monocyclic or polycyclic. Further, the alicyclic structure may have a substituent. Examples of the substituent include an alkyl group having 1 to 8 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, and the like. Examples of the alicyclic structure include, but are not limited to, a cycloalkane ring, a cycloalkene ring, a bicycloalkane ring, a bicycloalkene ring, and a tricycloalkane ring. Among these, preferably a cycloalkane ring, more preferably a cycloalkane ring having 5 to 8 carbon atoms, still more preferably at least one member selected from the group consisting of a cyclopropane ring and a cyclohexane ring, even more preferably a cyclohexane ring. .

[0020] The aromatic ring may be a single ring or a condensed ring, and examples thereof include, but are not limited to, a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, and a tetracene ring. Among these, at least one ring selected from the group consisting of a benzene ring and a naphthalene ring is preferred, and a benzene ring is more preferred.

[0021] As the heterocyclic structure, a ring structure containing at least one nitrogen atom as an element constituting the ring structure is preferable, and examples thereof include a piperazine ring, a piperidine ring, a pyridine ring, a pyrimidine ring, and the like.

[0022] The number of amino groups that the polyamine has is preferably 2 to 4, more preferably 2. The amino group may be directly connected to the ring structure, but from the viewpoint of improving the curing rate, it is preferable to have at least one amino group that is not directly connected to the ring structure.

[0023] Specific examples of the polyamine include aromatic ring-containing aliphatic polyamines such as ortho-xylylene diamine, meta-xylylene diamine (MXDA), and para-xylylene diamine (PXDA); isophorone diamine (IPDA), menthene diamine, norbornane diamine, Tricyclodecanediamine, adamantane diamine, diaminocyclohexane, 1,2-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,4-diamino- 2-Methylcyclohexane, 1,4-diamino-3,6-diethylcyclohexane, diaminodiethylmethylcyclohexane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane (bis(4-amino-3-methylcyclohexyl) Polyamines with alicyclic structures such as methane), 3,3',5,5'-tetramethyl-4,4'-diaminodicyclohexylmethane, and 4,4'-diaminodicyclohexylmethane; phenylenediamine, diaminodiphenylmethane, diamino Aromatic polyamines such as diphenylsulfone, diethyltoluenediamine, and 2,2'-diethyl-4,4'-methylene dianiline; heterocyclics such as N-aminoethylpiperazine and N,N'-bis(aminoethyl)piperazine Examples include polyamines having a structure, and one type of these can be used alone or two or more types can be used in combination.

[0024] Examples of modified polyamines include Mannich modified products, epoxy modified products, Michael adducts, Michael addition / polycondensates, styrene modified products, polyamide modified products, etc. of the polyamines, and epoxy modified products of the polyamines are preferred. . The epoxy-modified product of the polyamine is a reaction product of the polyamine and an epoxy compound having at least one epoxy group, and the method for producing the epoxy compound, the epoxy-modified product, and their preferred range are as follows: component (A) The content is the same as that described in the explanation of the epoxy-modified diamine.

[0025] In addition, in the curing agent of the present invention, when component (A) is an epoxy-modified product of a diamine represented by the above general formula (1), and component (B) is an epoxy-modified product of a polyamine having a ring structure, A mixture of component (A) and component (B) can also be produced by reacting a mixture of the diamine represented by the general formula (1) and the polyamine having the ring structure with the epoxy compound. .

[0026] Among the above, component (B) is preferably a polyamine having an alicyclic structure or a modified product thereof, such as isophorone diamine, menthene diamine , norbornane diamine, tricyclodecane diamine, adamantane diamine, diaminocyclohexane, 1,2-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1, 4-Diamino-2-methylcyclohexane, 1,4-diamino-3,6-diethylcyclohexane, diaminodiethylmethylcyclohexane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane (bis(4-amino-3 -methylcyclohexyl)methane), 3,3',5,5'-tetramethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylmethane, or modified products thereof, and isophoronediamine, At least one member selected from the group consisting of 1,3-bis(aminomethyl)cyclohexane or modified products thereof is more preferred, and isophoronediamine, 1,3-bis(aminomethyl)cyclohexane, or epoxy modified products thereof are more preferred. Even more preferably, it contains at least one member selected from the group consisting of an epoxy-modified product of isophoronediamine and an epoxy-modified product of 1,3-bis(aminomethyl)cyclohexane, which has fast curing properties and low viscosity. From this point of view, it is even more preferable to include an epoxy modified product of 1,3-bis(aminomethyl)cyclohexane. When component (B) contains at least one selected from the group consisting of an epoxy-modified product of isophoronediamine and an epoxy-modified product of 1,3-bis(aminomethyl)cyclohexane, the epoxy-modified product in component (B) From the viewpoint of fast curing, low viscosity, and improving the hardness of the coating film, the content of the substance is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, and more. More preferably, the content is 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and 100% by mass or less.

[0027] The molar ratio of component (A) and component (B) in the epoxy resin curing agent of the present invention is preferably 1 / 99 to 99 from the viewpoint of quick curing, low viscosity, and balance of coating hardness. / 1, more preferably 10 / 90 to 90 / 10, even more preferably 20 / 80 to 80 / 20, even more preferably 30 / 70 to 70 / 30, even more preferably 40 / 60 to 60 / 40 .

[0028] The curing agent of the present invention may be an epoxy resin curing agent consisting of component (A) and component (B), or may contain other curing agent components. Examples of other curing agent components include polyamine curing agents other than component (A) and component (B), phenol curing agents, acid anhydride curing agents, and the like. However, the total content of component (A) and component (B) in the curing agent of the present invention is determined from the viewpoint of fast curing property, low viscosity, and improvement of coating hardness. , preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably It is 95% by mass or more and 100% by mass or less. The total curing agent component in the curing agent means the total amount of components contained in the curing agent that have two or more active hydrogens that can react with the epoxy groups in the epoxy resin.

[0029] The active hydrogen equivalent of the curing agent of the present invention is preferably 25 or more from the viewpoint of improving the hardness of the coating film, and preferably 150 or less, more preferably 130 or less from the viewpoint of improving low viscosity and fast curing property. be. The active hydrogen equivalent (hereinafter also referred to as "AHEW") is the mass per mole of active hydrogen of the epoxy resin curing agent.

[0030] The epoxy resin curing agent of the present invention has a low viscosity. For example, the viscosity of a benzyl alcohol solution of the epoxy resin curing agent at a concentration of 60% by mass at 25°C is preferably 1,800 mPa·s or less, more preferably 1,500 mPa·s or less. s or less, more preferably 1,200 mPa·s or less. The lower limit of the viscosity is not particularly limited, but is usually 50 mPa·s or more. The viscosity at 25° C. of a benzyl alcohol solution containing an epoxy resin curing agent having a concentration of 60% by mass can be measured using an E-type viscometer, and specifically, by the method described in Examples.

[0031] [Epoxy resin composition] The epoxy resin composition of the present invention contains an epoxy resin and the epoxy resin curing agent. Since the epoxy resin composition of the present invention contains the epoxy resin curing agent, it can be cured quickly, has a low viscosity, and can form a coating film with high hardness.

[0032] <Epoxy resin> The epoxy resin, which is the main ingredient of the epoxy resin composition, may be any of saturated or unsaturated aliphatic compounds, alicyclic compounds, aromatic compounds, and heterocyclic compounds. From the viewpoint of obtaining a highly hard coating film, the epoxy resin preferably contains an aromatic ring or an alicyclic structure in the molecule. Specific examples of the epoxy resin include epoxy resins having glycidylamino groups derived from meta-xylylene diamine, epoxy resins having glycidylamino groups derived from para-xylylene diamine, and 1,3-bis(aminomethyl). Epoxy resin with glycidylamino groups derived from cyclohexane, epoxy resin with glycidylamino groups derived from 1,4-bis(aminomethyl)cyclohexane, epoxy resin with glycidylamino groups derived from diaminodiphenylmethane, para-amino Epoxy resins with glycidylamino and / or glycidyloxy groups derived from phenol, epoxy resins with glycidyloxy groups derived from bisphenol A, epoxy resins with glycidyloxy groups derived from bisphenol F, phenol novolaks At least one resin selected from epoxy resins having glycidyloxy groups derived from resorcinol and epoxy resins having glycidyloxy groups derived from resorcinol can be mentioned. The above epoxy resins can also be used in combination of two or more.

[0033] Among the above, from the viewpoint of obtaining a coating film with high hardness, the epoxy resins include an epoxy resin having a glycidylamino group derived from metaxylylene diamine, an epoxy resin having a glycidylamino group derived from paraxylylene diamine, Preferably, the main component is at least one selected from the group consisting of epoxy resins having glycidyloxy groups derived from bisphenol A and epoxy resins having glycidyloxy groups derived from bisphenol F, and is suitable for high hardness coatings. From the viewpoint of obtaining a membrane, availability, and economy, it is more preferable to use an epoxy resin having a glycidyloxy group derived from bisphenol A as a main component. Note that the "main component" here means that other components may be included without departing from the spirit of the present invention, and is preferably 50 to 100% by mass, more preferably 70 to 100% by mass of the whole. , more preferably 90 to 100% by mass.

[0034] The content of the epoxy resin as the main ingredient in the epoxy resin composition of the present invention is preferably 30 to 90% by mass, more preferably 40 to 90% by mass, from the viewpoint of fast curing, low viscosity, and improving the hardness of the coating film. It is 80% by mass, more preferably 50 to 75% by mass.

[0035] The content of the epoxy resin curing agent in the epoxy resin composition of the present invention is determined by the ratio of the number of active hydrogens in the epoxy resin curing agent to the number of epoxy groups in the epoxy resin (number of active hydrogens in the epoxy resin curing agent / number of active hydrogens in the epoxy resin). (number of epoxy groups) is preferably 1 / 0.5 to 1 / 2, more preferably 1 / 0.75 to 1 / 1.5, and still more preferably 1 / 0.8 to 1 / 1.2. Further, the content of the epoxy resin curing agent in the epoxy resin composition of the present invention is preferably 10 to 70% by mass, more preferably 15 to 70% by mass, from the viewpoint of fast curing, low viscosity, and improvement in the hardness of the coating film. The content is 50% by mass, more preferably 15 to 35% by mass.

[0036] The epoxy resin composition of the present invention may further contain known curing accelerators, non-reactive diluents such as benzyl alcohol, etc., within a range that does not impair the effects of the present invention.

[0037] In addition, the epoxy resin composition of the present invention may further contain 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. It may be included depending on the purpose. However, from the viewpoint of effectively obtaining the effects of the present invention, the total content of the epoxy resin and epoxy resin curing agent in the epoxy resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably It is 80% by mass or more and 100% by mass or less.

[0038] There are no particular limitations on the method for preparing the epoxy resin composition of the present invention, and the epoxy resin composition can be produced by mixing an epoxy resin, an epoxy resin curing agent, and other components as necessary using known methods and equipment. There is no particular restriction on the mixing order of each component contained in the epoxy resin composition. After preparing the epoxy resin curing agent, it may be mixed with the epoxy resin, or the components constituting the epoxy resin curing agent (A ), component (B), and other components may be mixed simultaneously with an epoxy resin.

[0039] [paint] The present invention provides a paint containing the epoxy resin composition. By containing the above-mentioned epoxy resin composition, the coating material of the present invention can form a coating film that cures quickly, has low viscosity, and has high hardness. Examples of such paints include marine paints, heavy anticorrosive paints, tank paints, pipe interior paints, exterior paints, flooring paints, and the like.

[0040] The content of the epoxy resin composition in the coating material of the present invention is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably is 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and 100% by mass or less.

Example

[0041] 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 Examples below. The epoxy resin curing agent, epoxy resin composition, and cured product (coating film) thereof were evaluated according to the following method.

[0042] <Dry to the touch> A zinc phosphate treated steel plate (manufactured by Paltec Corporation; SPCC-SD PB-N144 0.8×70×150 mm) was used as the base material. The epoxy resin composition of each example was applied onto the base material using an applicator under conditions of 23° C. and 50% R.H. to form a coating film (coating film thickness immediately after application: 200 μm). This coating film was stored under conditions of 23°C and 50% R.H., and after 1, 2, and 7 days, it was evaluated by touch according to the following criteria. The results are shown in Table 1. Ex: Excellent (no stickiness of the paint film and no fingerprints left even when pressing the thumb with a force of about 50N) G: Good (There is no stickiness of the paint film when you press your thumb with a force of about 50N, but there are some fingerprints left after touching it) F: Acceptable (paint becomes sticky when pressed with thumb with approx. 50N force) P: Poor (paint becomes sticky when pressed with thumb with approx. 5N force)

[0043] <Pencil hardness> The epoxy resin composition was applied onto the base material (zinc phosphate treated steel plate) in the same manner as above to form a coating film (thickness immediately after application: 200 μm). This coating film was stored under conditions of 23° C. and 50% R.H., and after 1, 2, and 7 days, the pencil hardness was measured according to JIS K5600-5-4:1999. The results are shown in Table 1.

[0044] <Water resistance spot test> The epoxy resin composition was applied onto the base material (zinc phosphate treated iron plate) in the same manner as described above to form a coating film (thickness immediately after application: 200 μm). Store this coating film under conditions of 23℃ and 50% R.H. After 1, 2, and 7 days, drop 2 to 3 drops of pure water on the coating surface with a dropper, and cover the area with a 50mL screw tube bottle. did. After 24 hours, the water was wiped off, the appearance was visually observed, and the appearance was evaluated according to the following criteria. The results are shown in Table 1. Ex: No change G: There is a slight change, but it is good. F: Changed

[0045] <RCI curing time> The epoxy resin composition of each example was applied onto a glass plate (manufactured by Taiyu Kizai Co., Ltd., 25 x 348 x 2.0 mm) at 23°C and 50% R.H. using a 76 μm applicator to form a coating film. . Set the glass plate on which the paint film has been formed on a paint drying time measuring device (manufactured by Taiyu Kizai Co., Ltd.), and observe the streaks caused by the needle of the measuring device scratching the surface of the paint film. The time required to reach dryness to the touch, semi-dryness, and complete dryness was measured using the following criteria. The results are shown in Table 1. The shorter the time, the faster the curing speed. Set to Touch: Time at which needle marks begin to remain on the glass plate. Semi-drying (Dust Free): The time it takes for needle marks to emerge from within the paint film onto the paint film surface. Complete drying (Dry through): Time until needle marks remain on the coating film.

[0046] <Appearance of paint film> The epoxy resin composition was applied onto the base material (zinc phosphate treated steel plate) in the same manner as above to form a coating film (thickness immediately after application: 200 μm). The appearance of the resulting coating film was visually observed after one day had passed, and transparency, smoothness, and gloss were evaluated using the following criteria. (transparency) Ex: Excellent (no cloudiness) G: Good (slightly cloudy, but no problem in use) F: Fair (slightly cloudy) P: Poor (cloudy) (Smoothness) Ex: Excellent (no unevenness) G: Good (slightly uneven, but no problem in use) F: Acceptable (some parts are uneven) P: Poor (there is repellency or unevenness on the entire surface) (Glossiness) Ex: Excellent (glossy) G: Good (slightly less glossy, but no problem in use) F: Acceptable (less gloss) P: Poor (no gloss)

[0047] <Viscosity of curing agent solution> The viscosity at 25°C of the epoxy resin curing agent solution in each example was measured using an E-type viscometer "TVE-22H Viscometer Cone Plate Type" (manufactured by Toki Sangyo Co., Ltd.).

[0048] Example 1 (Preparation and evaluation of epoxy resin curing agent solution and epoxy resin composition) (Preparation of epoxy resin curing agent solution A) 2-aminomethylcyclopentylamine (hereinafter referred to as AMCPA) and 1,3-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., 1,3-BAC) are used as the raw material diamine, and bisphenol A is used as the epoxy compound. Using a polyfunctional epoxy resin having a derived glycidyloxy group ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 186 g / equivalent), epoxy resin curing agent AMCPA and 1, An epoxy modified product of 3-BAC (molar ratio 50 / 50) was obtained. 228 g of 2-aminomethylcyclopentylamine and 284 g of 1,3-bis(aminomethyl)cyclohexane were placed in a 1 liter separable flask equipped with a stirrer, thermometer, nitrogen inlet tube, dropping funnel, and cooling tube. The temperature was raised to 80° C. with stirring under a nitrogen stream. While maintaining the temperature at 80° C., 372 g of an epoxy compound (“jER828” manufactured by Mitsubishi Chemical Corporation) was added dropwise over 2 hours. After the dropwise addition was completed, the temperature was raised to 100°C and reaction was carried out for 2 hours to obtain an epoxy modified product of AMCPA and 1,3-BAC (molar ratio 50 / 50). Note that the number of active hydrogens in the raw material diamine / the number of epoxy groups in the epoxy compound is 8 / 1.

[0049] The obtained epoxy modified product was diluted by adding benzyl alcohol, which is a non-reactive diluent, in an amount of 40% by mass based on the total amount to obtain an epoxy resin curing agent solution with a concentration of 60% by mass of the epoxy modified product. I got an A. The active hydrogen equivalent (AHEW) of the epoxy resin curing agent solution A (total amount including benzyl alcohol) was 105.

[0050] (Preparation of epoxy resin composition) As the epoxy resin which is the main ingredient of the epoxy resin composition, a polyfunctional liquid epoxy resin having a glycidyloxy group derived from bisphenol A (“jER828” manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 186 g / equivalent) was used. The epoxy resin and the epoxy resin curing agent solution A are mixed at a ratio of the number of active hydrogens in the epoxy resin curing agent to the number of epoxy groups in the epoxy resin (number of active hydrogens in the epoxy resin curing agent / number of epoxy groups in the epoxy resin). ) were blended and mixed in a ratio of 1 / 1 to prepare an epoxy resin composition. Using the obtained epoxy resin composition, various evaluations were performed using the methods described above. The results are shown in Table 1.

[0051] Example 2 (Preparation of epoxy resin curing agent solution B) Epoxy resin was cured in the same manner as in Example 1, except that the amount of AMCPA used in Example 1 was changed to 228 g, and 340 g of isophorone diamine (IPDA) was used instead of 1,3-BAC. An epoxy modified product of AMCPA and IPDA (molar ratio 50 / 50) was obtained. Benzyl alcohol, which is a non-reactive diluent, was added thereto in an amount of 40% by mass of the total amount to dilute it, to obtain an epoxy resin curing agent solution B having a concentration of 60% by mass of the epoxy modified product. The active hydrogen equivalent of the epoxy resin curing agent solution B (total amount including benzyl alcohol) was 112.

[0052] (Preparation of epoxy resin composition) In Example 1, an epoxy resin composition was prepared in the same manner as in Example 1, except that epoxy resin hardener solution B was used instead of epoxy resin hardener solution A, and various evaluations were performed using the methods described above. I did it. The results are shown in Table 1.

[0053] Comparative example 1 (Preparation of comparative epoxy resin curing agent solution a) In Example 1, the epoxy resin curing agent 1, An epoxy modified product of 3-BAC was obtained. Benzyl alcohol, which is a non-reactive diluent, was added thereto in an amount of 40% by mass of the total amount to dilute it, to obtain a comparative epoxy resin curing agent solution a having a concentration of the epoxy modified product of 60% by mass. The active hydrogen equivalent of the comparative epoxy resin curing agent solution a (total amount including benzyl alcohol) was 112.

[0054] (Preparation of epoxy resin composition) In Example 1, an epoxy resin composition was prepared in the same manner as in Example 1, except that comparative epoxy resin hardener solution A was used instead of epoxy resin hardener solution A, and various We conducted an evaluation. The results are shown in Table 1.

[0055] Comparative example 2 (Preparation of comparative epoxy resin curing agent solution b) An epoxy modified product of IPDA, which is an epoxy resin curing agent, was obtained in the same manner as in Comparative Example 1, except that 680 g of IPDA was used instead of 568 g of 1,3-BAC. Benzyl alcohol, which is a non-reactive diluent, was added thereto in an amount of 40% by mass of the total amount to dilute it, to obtain a comparative epoxy resin curing agent solution b having a concentration of the epoxy modified product of 60% by mass. The active hydrogen equivalent of the comparative epoxy resin curing agent solution b (total amount including benzyl alcohol) was 125.

[0056] (Preparation of epoxy resin composition) In Comparative Example 1, an epoxy resin composition was prepared in the same manner as in Comparative Example 1, except that comparative epoxy resin curing agent solution b was used instead of comparative epoxy resin curing agent solution a, and an epoxy resin composition was prepared in the same manner as in Comparative Example 1. Various evaluations were conducted. The results are shown in Table 1.

[0057] Comparative example 3 (Preparation of comparative epoxy resin curing agent solution c) In Comparative Example 1, the epoxy resin curing agent, 1,3 An epoxy modified product of -BAC and IPDA (molar ratio 50 / 50) was obtained. Benzyl alcohol, which is a non-reactive diluent, was added thereto in an amount of 40% by mass of the total amount to dilute it, to obtain a comparative epoxy resin curing agent solution c having a concentration of the epoxy modified product of 60% by mass. The active hydrogen equivalent of the comparative epoxy resin curing agent solution c (total amount including benzyl alcohol) was 119.

[0058] (Preparation of epoxy resin composition) In Comparative Example 1, an epoxy resin composition was prepared in the same manner as in Comparative Example 1, except that Comparative Epoxy Resin Curing Agent Solution C was used in place of Comparative Epoxy Resin Curing Agent Solution A. Various evaluations were conducted. The results are shown in Table 1.

[0059] Comparative example 4 (Preparation of comparative epoxy resin curing agent solution d) In Example 1, AMCPA, which is an epoxy resin curing agent, and trimethylhexamethylene diamine (mol. An epoxy modified product with a ratio of 50 / 50 was obtained. Benzyl alcohol, which is a non-reactive diluent, was added thereto to dilute it in an amount of 40% by mass of the total amount to obtain a comparative epoxy resin curing agent solution d having a concentration of the epoxy modified product of 60% by mass. The active hydrogen equivalent of the comparative epoxy resin curing agent solution d (total amount including benzyl alcohol) was 109.

[0060] (Preparation of epoxy resin composition) In Example 1, an epoxy resin composition was prepared in the same manner as in Example 1, except that comparative epoxy resin curing agent solution d was used instead of epoxy resin curing agent solution A. We conducted an evaluation. The results are shown in Table 1.

[0061]

table 1

[0062] From Table 1, the epoxy resin curing agent of the present invention has fast curing properties and low viscosity. Furthermore, the coating film formed from the epoxy resin composition containing the curing agent had a short curing time (dry through) and reached a pencil hardness of 2H after 7 days, indicating high hardness. In contrast, the epoxy resin curing agent and epoxy resin composition of this comparative example were inferior in any of the curing speed, low viscosity, and hardness of the coating film. [Industrial applicability]

[0063] According to the present invention, it is possible to provide an epoxy resin curing agent, an epoxy resin composition, and a cured product thereof that cures quickly, has a low viscosity, and can form a highly hard coating film.

Claims

1. An epoxy resin curing agent comprising the following components (A) and (B): (A) A diamine represented by the following general formula (1) or a modified diamine thereof: 【Chemistry 1】 In formula (1), m and n each independently represent a number from 0 to 4. (B) A polyamine having a ring structure or a modified product thereof other than the component (A).

2. 2. The epoxy resin curing agent according to claim 1, wherein the component (B) is a polyamine having an alicyclic structure or a modified product thereof.

3. 3. The epoxy resin curing agent according to claim 2, wherein the component (B) is at least one selected from the group consisting of isophoronediamine, 1,3-bis(aminomethyl)cyclohexane, or modified products thereof.

4. 2. The epoxy resin curing agent according to claim 1, wherein the diamine represented by the general formula (1) is 2-aminomethylcyclopentylamine.

5. 2. The epoxy resin curing agent according to claim 1, wherein a molar ratio of said component (A) to said component (B) in said epoxy resin curing agent is 1 / 99 to 99 / 1.

6. An epoxy resin composition comprising an epoxy resin and the epoxy resin curing agent according to any one of claims 1 to 5.

7. A coating comprising the epoxy resin composition of claim 6.

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