Epoxy resin curing agent, epoxy resin composition and paint

Abstract

Provided are: an epoxy resin curing agent containing a polyamine (A) that includes a diamine (A1) represented by general formula (1), or containing an adduct-modified form of the polyamine (A); an epoxy resin composition; and a coating containing these. (In formula (1), R1-R8 each independently represent a hydrogen atom or a C1-5 aliphatic group.)

Description

[Technical Field]

[0001] The present invention relates to an epoxy resin curing agent, an epoxy resin composition, and a coating material. [Background technology]

[0002] Epoxy resin compositions using various polyamines such as xylylenediamine as epoxy resin curing agents are widely used in the fields of paints, such as anticorrosion paints for ships, bridges, and onshore and offshore steel structures, and in the fields of civil engineering and construction, such as linings, reinforcement, and repair materials for concrete structures, flooring materials for buildings, linings for water and sewer systems, paving materials, adhesives, etc. Of these, it is important for epoxy resin compositions for paints that the resulting coating film has good appearance, water resistance, chemical resistance, and other physical properties.

[0003] Polyamines such as xylylenediamine or modified products thereof are known to be useful as epoxy resin curing agents for coatings. For example, Patent Document 1 discloses that an epoxy resin composition containing a specified modified epoxy resin and an amine-based curing agent as essential components has low viscosity, excellent low-temperature curing properties, and excellent cured physical properties such as mechanical strength, moisture resistance, and adhesiveness, and is particularly suitable for civil engineering, paint, and adhesive applications. An example of the amine-based curing agent is one whose main component is a Mannich reaction modified product of meta-xylylenediamine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-191527 Summary of the Invention [Problem to be solved by the invention]

[0005] When used as an epoxy resin curing agent, metaxylylenediamine has the advantages of fast curing and high chemical resistance. However, metaxylylenediamine easily forms carbonates when reacting with carbon dioxide in the air. Therefore, when metaxylylenediamine or its modified derivatives are used as a curing agent, the resulting coating film can whiten (blush) and lose transparency. Furthermore, because metaxylylenediamine contains an aromatic ring, the resulting coating film can yellow over time, leaving room for improvement in weather resistance.

[0006] An object of the present invention is to provide an epoxy resin curing agent, an epoxy resin composition, and a coating material containing the same, which are capable of forming a coating film having excellent transparency and weather resistance. [Means for solving the problem]

[0007] The present inventors have found that an epoxy resin curing agent containing a polyamine containing a diamine of a specific structure or an adduct-modified product of the polyamine can solve the above problems. That is, the present invention relates to the following. [1] An epoxy resin curing agent containing a polyamine (A) containing a diamine (A1) represented by the following general formula (1) or an adduct-modified product of the polyamine (A). [ka] (In formula (1), R 1 ~R 8 each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms. [2] The epoxy resin curing agent according to the above [1], wherein the adduct-modified product is a reaction composition containing a reaction product of the polyamine (A) and an epoxy compound having at least one epoxy group. [3] The epoxy resin curing agent according to the above [1] or [2], wherein the diamine (A1) is at least one selected from the group consisting of diamines represented by the following formulae (1-1) to (1-3): [ka] [4] The epoxy resin curing agent according to any one of the above [1] to [3], wherein the content of the diamine (A1) in the polyamine (A) is 5% by mass or more. [5] The epoxy resin curing agent according to any one of the above [1] to [4], wherein the polyamine (A) further contains xylylenediamine. [6] The epoxy resin curing agent according to any one of the above [1] to [5], wherein the total content of the polyamine (A) and its adduct-modified product in all curing agent components contained in the epoxy resin curing agent is 50 mass% or more. [7] An epoxy resin composition containing an epoxy resin and the epoxy resin curing agent according to any one of the above [1] to [6]. [8] A paint containing the epoxy resin composition described in [7] above. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an epoxy resin curing agent, an epoxy resin composition, and a coating material containing the same, which are capable of forming a coating film having excellent transparency and weather resistance. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Epoxy resin hardener] The epoxy resin curing agent of the present invention is an epoxy resin curing agent containing a polyamine (A) containing a diamine (A1) represented by the following general formula (1) or an adduct-modified product of the polyamine (A). That is, the curing agent contains at least one member selected from the group consisting of the polyamine (A) and the adduct-modified product of the polyamine (A). [ka] (In formula (1), R 1 ~R 8 each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms. By using the above-mentioned epoxy resin curing agent, it is possible to provide an epoxy resin composition that can form a coating film excellent in transparency and weather resistance. Hereinafter, the epoxy resin curing agent of the present invention may also be simply referred to as "the curing agent of the present invention."

[0010] The reason why the use of the curing agent of the present invention in an epoxy resin composition enables the formation of a coating film having excellent transparency and weather resistance is not clear, but is thought to be as follows. As mentioned above, xylylenediamine has the problem that it reacts with carbon dioxide in the air to form carbonates, which can easily turn white, and because it contains an aromatic ring, it is prone to yellowing over time.Furthermore, because xylylenediamine has a benzyl skeleton, the hydrogen atom at the benzyl position is easily abstracted, which is thought to result in a decrease in weather resistance. In contrast, the diamine (A1) represented by the general formula (1) is more stable than xylylenediamine because it is less likely to abstract hydrogen atoms, and is less likely to whiten even when in contact with carbon dioxide. Therefore, it is believed that an epoxy resin composition containing the epoxy resin curing agent of the present invention using the diamine (A1) will form a coating film with good transparency and weather resistance.

[0011] (Diamine (A1)) The diamine (A1) is a diamine represented by the following general formula (1). [ka] (In formula (1), R 1 ~R 8 each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms. R in the general formula (1) 1 ~R 8In the formula (I), examples of the aliphatic group having 1 to 5 carbon atoms include an alkyl group having 1 to 5 carbon atoms, and an alkenyl or alkynyl group having 2 to 5 carbon atoms. From the viewpoint of forming a coating film that is excellent in transparency and weather resistance, the aliphatic group is preferably an alkyl group having 1 to 5 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an i-pentyl group, and the like. Of these, from the viewpoint of forming a coating film that is excellent in transparency and weather resistance, an alkyl group having 1 to 3 carbon atoms is preferred, a methyl group or an ethyl group is more preferred, and a methyl group is even more preferred.

[0012] From the viewpoint of forming a coating film excellent in transparency and weather resistance, and from the viewpoint of improving curability, R 1 ~R 8 are preferably each independently a hydrogen atom or a methyl group, and R 1 ~R 8 It is more preferable that four or more of R 1 ~R 8 It is more preferable that six or more of R 1 ~R 8 may all be hydrogen atoms. In a more preferred embodiment, in the general formula (1), R 3 , R 4 , R 7 , and R 8 is a hydrogen atom and R 1 , R 2 , R 5 , and R 6 is a hydrogen atom or a methyl group, and in a more preferred embodiment, R 2 , R 3 , R 4 , R 5 , R 7 , and R 8 is a hydrogen atom and R 1 and R 6 is a hydrogen atom or a methyl group.

[0013] From the viewpoint of forming a coating film having excellent transparency and weather resistance, and from the viewpoint of improving curability, the diamine (A1) is preferably a diamine represented by the following general formula (1'), and more preferably at least one selected from the group consisting of diamines represented by the following formulas (1-1) to (1-4): [ka] (In formula (1'), R 1 , R 2 , R 5 , and R 6 each independently represents a hydrogen atom or a methyl group. [ka]

[0014] From the viewpoint of forming a coating film having excellent transparency and weather resistance, and from the viewpoint of improving curability, the diamine (A1) is more preferably at least one selected from the group consisting of diamines represented by the following formulas (1-1) to (1-3): [ka]

[0015] From the viewpoint of forming a coating film having excellent transparency and water resistance, the diamine (A1) is preferably at least one selected from the group consisting of the diamines represented by the above formula (1-2) and the diamines represented by the above formula (1-3). From the viewpoint of forming a coating film having even better weather resistance, the diamine (A1) is preferably at least one selected from the group consisting of the diamines represented by the above formula (1-1) and the diamines represented by the above formula (1-2).

[0016] The diamine (A1) represented by the general formula (1) can be produced by a known method. For example, the diamine represented by the formula (1-1) (p-benzenediethaneamine; pBDEA) can be obtained by reducing p-xylylene dicyanide under a hydrogen atmosphere. The diamine represented by the formula (1-2) (2-[4-(2-amino-1-methylethyl)phenyl]propylamine; pBDEA-2M) can be produced according to the description in Example 1 of JP-A-2004-503527. The diamine represented by the formula (1-3) (m-benzenediethaneamine; mBDEA) can be obtained by reducing m-xylylene dicyanide under a hydrogen atmosphere. The diamine represented by the formula (1-4) can be produced according to the description in Example 3 of JP-A-2004-503527.

[0017] <Polyamine (A)> The polyamine (A) used in the curing agent of the present invention contains the diamine (A1) represented by the general formula (1) above. From the viewpoint of forming a coating film excellent in transparency and weather resistance, the content of the diamine (A1) in the polyamine (A) is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 5% by mass or more, still more preferably 10% by mass or more, still more preferably 15% by mass or more, still more preferably 20% by mass or more, still more preferably 30% by mass or more, still more preferably 40% by mass or more, still more preferably 50% by mass or more, and is 100% by mass or less.

[0018] The polyamine (A) may contain a polyamine other than the diamine (A1). The polyamine other than the diamine (A1) is not particularly limited as long as it is a compound having at least two amino groups in the molecule. Examples include 1,2-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, orthoxylenediamine, metaxylylenediamine (MXDA), paraxylylenediamine (PXDA), menthenediamine, isophoronediamine (IPDA), diaminodicyclohexylmethane, bis(4-amino-3-methylcyclohexyl)methane, N-aminomethylpiperazine, norbornanediamine, bis(aminomethyl)tricyclodecane, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyoxyalkylenediamine, and polyoxyalkylenetriamine. These may be used alone or in combination of two or more. Among the above, from the viewpoint of obtaining an effect of improving the transparency and weather resistance of the resulting coating film by containing polyamine (A) or its adduct-modified product, and from the viewpoint of obtaining curability and good coating film properties, the polyamine other than diamine (A1) is preferably xylylenediamine, more preferably one or more selected from the group consisting of metaxylylenediamine and paraxylylenediamine, and even more preferably metaxylylenediamine. That is, polyamine (A) preferably further contains xylylenediamine in addition to the diamine (A1), more preferably one or more selected from the group consisting of metaxylylenediamine and paraxylylenediamine, and even more preferably metaxylylenediamine.

[0019] When the polyamine (A) contains a polyamine other than the diamine (A1), the mass ratio of the diamine (A1) in the polyamine (A) to the polyamine other than the diamine (A1) is preferably 1 / 99 to 99 / 1, more preferably 5 / 95 to 99 / 1, even more preferably 10 / 90 to 99 / 1, and still more preferably 15 / 85 to 99 / 1, from the viewpoint of forming a coating film excellent in transparency and weather resistance. When diamine (A1) is a diamine represented by the formula (1-1) and the polyamine other than diamine (A1) is xylylenediamine, the mass ratio of diamine represented by formula (1-1) to xylylenediamine is more preferably 20 / 80 to 99 / 1, even more preferably 30 / 70 to 95 / 5, and even more preferably 40 / 60 to 90 / 10, from the viewpoint of forming a coating film excellent in transparency, weather resistance, and water resistance. When diamine (A1) is a diamine represented by the formula (1-2) and the polyamine other than diamine (A1) is xylylenediamine, the mass ratio of diamine represented by formula (1-2) to xylylenediamine is more preferably 20 / 80 to 99 / 1, and even more preferably 30 / 70 to 99 / 1, from the viewpoint of forming a coating film excellent in transparency, weather resistance, and water resistance. When the diamine (A1) is a diamine represented by the formula (1-3) and the polyamine other than the diamine (A1) is xylylenediamine, the mass ratio of the diamine represented by the formula (1-3) to the xylylenediamine is even more preferably 20 / 80 to 99 / 1, from the viewpoint of forming a coating film excellent in transparency, weather resistance, and water resistance.

[0020] <Adduct modified polyamine (A)> Specific examples of the adduct-modified polyamine (A) include a reaction product obtained by reacting polyamine (A) with an epoxy compound having at least one epoxy group, an unsaturated hydrocarbon compound, a carboxylic acid or a derivative thereof, etc.; a Mannich reaction product obtained by reacting polyamine (A) with a phenol compound and an aldehyde compound; and a ketimine (ketimine) obtained by reacting polyamine (A) with a ketone compound. Among these, the adduct-modified polyamine (A) is preferably a reaction composition containing a reaction product of polyamine (A) and an epoxy compound having at least one epoxy group, from the viewpoint of forming a coating film having excellent transparency and weather resistance, and from the viewpoint of improving water resistance. In this specification, a reaction composition containing a reaction product of polyamine (A) and an epoxy compound having at least one epoxy group refers to a reaction composition that is a product obtained by the reaction of polyamine (A) with the epoxy compound, and contains a reaction product (adduct) of the diamine and the epoxy compound. The reaction composition may contain unreacted raw materials, etc. Hereinafter, the reaction composition will also be simply referred to as "the reaction composition."

[0021] The epoxy compound used in the reaction composition may be a compound having at least one epoxy group, and more preferably a compound having two or more epoxy groups. Specific examples of the epoxy compound include epichlorohydrin, butyl diglycidyl ether, neopentyl glycol diglycidyl ether, 1,3-propanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, biphenol diglycidyl ether, dihydroxynaphthalene diglycidyl ether, dihydroxyanthracene diglycidyl ether, triglycidyl isocyanurate, tetraglycidyl glycoluril, and a polyfunctional epoxy resin having a glycidylamino group derived from metaxylylenediamine; Examples of such epoxy resins include polyfunctional epoxy resins having glycidylamino groups derived from diaminodiphenylmethane, polyfunctional epoxy resins having glycidylamino groups and / or glycidyloxy groups derived from paraaminophenol, 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 novolac, and polyfunctional epoxy resins having two or more glycidyloxy groups derived from resorcinol. These may be used alone or in combination of two or more. From the viewpoints of forming a coating film having excellent transparency and weather resistance, improving water resistance, and curing properties, the epoxy compound is more preferably a compound containing an aromatic ring or an alicyclic structure in the molecule, even more preferably a compound containing an aromatic ring in the molecule, and even more preferably a polyfunctional epoxy resin having a glycidyloxy group derived from bisphenol A.

[0022] The reaction composition can be obtained by subjecting polyamine (A) and an epoxy compound to a ring-opening addition reaction using a known method. For example, a reaction vessel is charged with polyamine (A), and the epoxy compound is added thereto all at once or in portions, such as by dropwise addition, followed by heating and reaction. The addition reaction is preferably carried out under an inert atmosphere such as nitrogen gas.

[0023] The amounts of polyamine (A) and epoxy compound used are not particularly limited as long as the resulting reaction product contains an amino group having active hydrogen. From the viewpoint of the resulting reaction product functioning as an epoxy resin curing agent, it is preferable to use an excess amount of polyamine (A) relative to the epoxy equivalent of the epoxy compound in the addition reaction. Specifically, the polyamine (A) and epoxy compound are used so that the ratio of the number of active hydrogens in polyamine (A) to the number of epoxy groups in the epoxy compound (number of active hydrogens in polyamine (A) / number of epoxy groups in epoxy compound) is preferably 50 / 1 to 4 / 1, more preferably 20 / 1 to 4 / 1.

[0024] The temperature and reaction time during the addition reaction can be selected as appropriate, but from the viewpoints 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 120° C. The reaction time is preferably 0.5 to 12 hours, more preferably 1 to 6 hours, after completion of addition of the epoxy compound.

[0025] The curing agent of the present invention may be a curing agent comprising polyamine (A) or its adduct-modified product, or may contain other curing agent components, such as phenol-based curing agents, other than polyamines and their adduct-modified products. However, from the viewpoint of forming a coating film excellent in transparency and weather resistance, the total content of polyamine (A) and its adduct-modified product in all curing agent components contained in the curing agent of the present invention is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass or more, and is 100% by mass or less.

[0026] From the viewpoints of curability and obtaining good coating film properties, the curing agent of the present invention preferably contains an adduct-modified polyamine (A), and more preferably contains a reaction composition containing a reaction product of polyamine (A) and an epoxy compound having at least one epoxy group. When the curing agent of the present invention contains the reaction composition as the adduct-modified polyamine (A), the content of the reaction composition in the curing agent of the present invention is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass or more, and 100% by mass or less, based on the total curing agent components in the curing agent, from the viewpoints of forming a coating film excellent in transparency and weather resistance, curability, and obtaining good coating film properties. The curing agent component in the curing agent means a component contained in the curing agent that has two or more active hydrogens capable of reacting with epoxy groups in the epoxy resin, and the mass % of the reactive composition relative to the total amount of curing agent components in the curing agent refers to the content ratio of the reactive composition relative to the total amount of curable components contained in the curing agent.

[0027] The curing agent of the present invention may further contain known curing accelerators, non-reactive diluents such as benzyl alcohol, etc., within the range that does not impair the effects of the present invention.

[0028] The active hydrogen equivalent of the curing agent component in the curing agent of the present invention depends on the components contained in the curing agent, but from the viewpoint of obtaining good coating film properties, it is preferably 40 or more, and from the viewpoint of improving curing properties, it is preferably 150 or less. The active hydrogen equivalent (hereinafter also referred to as "AHEW") is the mass per mole of active hydrogen in the epoxy resin curing agent.

[0029] [Epoxy resin composition] The epoxy resin composition of the present invention contains an epoxy resin and the epoxy resin curing agent. A coating film formed from the epoxy resin composition of the present invention has high transparency and weather resistance, and is suitable for use as, for example, a paint.

[0030] <Epoxy resin> The epoxy resin, which is the main component of the epoxy resin composition, may be any of a saturated or unsaturated aliphatic compound, alicyclic compound, aromatic compound, and heterocyclic compound. From the viewpoint of obtaining a cured product with high water resistance, an epoxy resin containing an aromatic ring or alicyclic structure in the molecule is preferred. Specific examples of the epoxy resin include at least one resin selected from the group consisting of epoxy resins having glycidylamino groups derived from meta-xylylenediamine, epoxy resins having glycidylamino groups derived from para-xylylenediamine, epoxy resins having glycidylamino groups derived from 1,3-bis(aminomethyl)cyclohexane, epoxy resins having glycidylamino groups derived from 1,4-bis(aminomethyl)cyclohexane, epoxy resins having glycidylamino groups derived from diaminodiphenylmethane, epoxy resins having glycidylamino groups and / or glycidyloxy groups derived from para-aminophenol, epoxy resins having glycidyloxy groups derived from bisphenol A, epoxy resins having glycidyloxy groups derived from bisphenol F, epoxy resins having glycidyloxy groups derived from phenol novolac, and epoxy resins having glycidyloxy groups derived from resorcinol. Two or more of the above epoxy resins can also be used in combination.

[0031] Among the above, from the viewpoint of obtaining good coating film properties, the epoxy resin is preferably one having as its main component at least one selected from the group consisting of epoxy resins having a glycidylamino group derived from meta-xylylenediamine, epoxy resins having a glycidylamino group derived from para-xylylenediamine, epoxy resins having a glycidyloxy group derived from bisphenol A, and epoxy resins having a glycidyloxy group derived from bisphenol F, and from the viewpoint of obtaining good coating film properties, availability, and economy, one having as its main component an epoxy resin having a glycidyloxy group derived from bisphenol A is more preferred. The term "main component" as used herein means that other components may be contained within the scope of the present invention, and preferably means 50 to 100% by mass of the total, more preferably 70 to 100% by mass, and even more preferably 90 to 100% by mass.

[0032] The content of the epoxy resin curing agent in the epoxy resin composition of the present invention is an amount such that the ratio of the number of active hydrogens in the epoxy resin curing agent to the number of epoxy groups in the epoxy resin (number of active hydrogens in the epoxy resin curing agent / number of epoxy groups in the epoxy resin) is preferably 1 / 0.5 to 1 / 2, more preferably 1 / 0.75 to 1 / 1.5, and even more preferably 1 / 0.8 to 1 / 1.2.

[0033] The epoxy resin composition of the present invention may further contain other components such as modifying components such as fillers and plasticizers, flow-adjusting components such as thixotropic agents, pigments, leveling agents, tackifiers, and elastomer fine particles, depending on the intended use. However, from the viewpoint of effectively obtaining the effects of the present invention, the total amount of the epoxy resin and the epoxy resin curing agent in the epoxy resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and still more preferably 95% by mass or more, and is 100% by mass or less.

[0034] The epoxy resin composition of the present invention can be prepared by mixing an epoxy resin, an epoxy resin curing agent, and other components as required using known methods and equipment. The order of mixing the components contained in the epoxy resin composition is also not particularly limited. The epoxy resin curing agent may be prepared and then mixed with the epoxy resin, or the epoxy resin may be prepared by simultaneously mixing the components constituting the epoxy resin curing agent and other components with the epoxy resin.

[0035] The coating film, which is a cured product of the epoxy resin composition of the present invention, can be obtained by curing the above-mentioned epoxy resin composition of the present invention by a known method. The curing conditions for the epoxy resin composition are appropriately selected depending on the application and form, and are not particularly limited. The coating film, which is a cured product of the epoxy resin composition of the present invention, is excellent in transparency and weather resistance, is less likely to cause whitening of the coating film, and can suppress the occurrence of yellowing over time after the formation of the coating film.

[0036] [Paint] The present invention provides a paint containing the epoxy resin composition. By containing the epoxy resin composition, the paint of the present invention has good transparency and weather resistance of the obtained coating film. Examples of the paint include marine paint, heavy anti-corrosion paint, tank paint, pipe interior paint, exterior paint, floor material paint, and the like.

[0037] From the viewpoint of improving transparency and weather resistance, the content of the epoxy resin composition in the paint of the present invention is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and may be 100% by mass.

Examples

[0038] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. The evaluation of the epoxy resin curing agent, the epoxy resin composition, and its cured product was carried out according to the following methods.

[0039] <RCI Curing Time> On a glass plate (manufactured by Taiyu Machinery Co., Ltd., 25 × 348 × 2.0 mm), the epoxy resin composition of each example was applied using a 76 μm applicator under the conditions of 23°C and 50% R.H. to form a coating film. The glass plate with the coating film formed was set in a paint drying time measuring device (manufactured by Taiyu Machinery Co., Ltd.), and the time to reach each drying stage (tacky dry, semi-dry, fully dry) was measured by observing the streak when the needle of the measuring device scratched the surface of the coating film according to the following criteria. The results are shown in Tables 1 to 4. The shorter the time, the faster the curing speed. Tacky Dry: The time when traces of the needle begin to remain on the glass plate Semi-Dry (Dust Free): The time when the trace of the needle emerges from the coating film onto the surface of the coating film Dry through: The time when no trace of the needle remains on the coating

[0040] <Coating film appearance (transparency)> A zinc phosphate-treated steel plate (SPCC-SD PB-N144, 0.8 × 70 × 150 mm, manufactured by Paltec Co., Ltd.) was used as the substrate. The epoxy resin composition of each example was applied to the substrate using an applicator at 23°C and 50% RH to form a coating film (coating film thickness immediately after application: 200 μm). This coating film was stored at 23°C and 50% RH, and after one day, the appearance was visually observed and the transparency was evaluated according to the following criteria. The results are shown in Tables 1 to 4. (transparency) Ex: No turbidity G: Slightly cloudy, but no problem for use F: Cloudy

[0041] <Dry to the touch> The epoxy resin composition was applied to a substrate (zinc phosphate-treated steel plate) in the same manner as above to form a coating film (thickness immediately after application: 200 μm). This coating film was stored under conditions of 23°C and 50% RH, and evaluated by touch after 1, 2, and 7 days according to the following criteria. The results are shown in Table 1. Ex: Excellent (the coating does not become sticky even when pressed with a thumb with a force of approximately 50N, and no fingerprints remain) G: Good (the coating is not sticky when pressed with a thumb with a force of about 50 N, but fingerprints remain after touching) F: Fair (the coating is sticky when pressed with a thumb with a force of about 50 N) P: Poor (the coating is sticky when pressed with a thumb with a force of about 5N)

[0042] <Pencil hardness> The epoxy resin composition was applied to a substrate (zinc phosphate-treated steel plate) in the same manner as above to form a coating film (thickness immediately after application: 200 μm). This coating film was stored under conditions of 23°C and 50% RH, and after 1, 2, and 7 days, the pencil hardness was measured in accordance with JIS K5600-5-4:1999. The results are shown in Table 1.

[0043] <Water resistance spot test> The epoxy resin composition was applied to a substrate (zinc phosphate-treated steel plate) in the same manner as above to form a coating film (thickness immediately after application: 200 μm). This coating film was stored under conditions of 23°C and 50% RH, and after 1, 2, and 7 days, 2 to 3 drops of pure water were applied to the coating surface using a dropper, and the area was then capped with a 50 mL screw cap. After 24 hours, the water was wiped off, and the appearance was visually observed and evaluated according to the following criteria. The results are shown in Tables 1 to 4. Ex: No change G: Slight changes, but good F: Change

[0044] <yi> Weather resistance tests were conducted in accordance with ISO4982 Part 3 Method A. The epoxy resin composition obtained in each example was cured in a 20 mm x 20 mm x 2 mm thick mold at 23°C and 50% RH for 7 days to prepare a test specimen. The YI value of this test specimen was measured in accordance with JIS K7373:2006 using a color difference meter ("COH400" manufactured by Nippon Denshoku Industries Co., Ltd.). The test specimen was then placed in a UV tester "Suntest XXL+" (manufactured by Toyo Seiki Seisakusho Co., Ltd.) and exposed to ultraviolet light with a wavelength of 300 to 400 nm from a xenon lamp at an illuminance of 60 W / m at a temperature of 38°C. 2 The UV irradiation intensity was 30,000 (kJ / m 2 ), the test piece was taken out and the YI value was measured in the same manner as above. The difference in the YI value before and after the weather resistance test was taken as the ΔYI value. The results are shown in Tables 1 to 4. The smaller the ΔYI value, the better the weather resistance of the cured product.

[0045] Production Example 1 (Synthesis of p-benzenediethaneamine (pBDEA)) p-Xylylene dicyanide (Tokyo Chemical Industry Co., Ltd.) was reduced under a hydrogen atmosphere, and the resulting product was purified by distillation to obtain p-benzenediethaneamine (pBDEA) represented by the following formula (1-1). Analysis by gas chromatography revealed that the purity was 99.7%. [ka]

[0046] Production Example 2 (Synthesis of 2-[4-(2-amino-1-methylethyl)phenyl]propylamine (pBDEA-2M) 2-[4-(2-amino-1-methylethyl)phenyl]propylamine dihydrochloride was obtained according to the description in Example 1 of JP-A 2004-503527. The hydrochloride was neutralized and then extracted with a solvent. The resulting extract was purified by distillation to obtain 2-[4-(2-amino-1-methylethyl)phenyl]propylamine (pBDEA-2M), a compound represented by formula (1-2). Analysis by gas chromatography revealed a purity of 94.6%. Furthermore, analysis by neutralization titration using dilute hydrochloric acid revealed an amino group concentration of 10.35 mmol / g. [ka]

[0047] Production Example 3 (Synthesis of m-benzenediethaneamine (mBDEA)) m-Xylylene dicyanide (Tokyo Chemical Industry Co., Ltd.) was reduced under a hydrogen atmosphere, and the resulting product was purified by distillation to obtain m-benzenediethylamine (mBDEA) represented by the following formula (1-3). Analysis by gas chromatography revealed that the purity was 99.6%. [ka]

[0048] Example 1 (Preparation and Evaluation of Epoxy Resin Curing Agent and Epoxy Resin Composition) [Preparation of epoxy resin curing agent] A 1-liter separable flask equipped with a stirrer, thermometer, nitrogen inlet tube, dropping funnel, and condenser was charged with 41.3 g of pBDEA obtained in Production Example 1 and heated to 80°C while stirring under a nitrogen stream. While maintaining the temperature at 80°C, 18.7 g (an amount such that the number of active hydrogens in the amine / the number of epoxy groups in the epoxy compound = 10 / 1) of a multifunctional epoxy resin ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 186 g / equivalent) derived from bisphenol A was added dropwise over 2 hours. After the addition was completed, the temperature was raised to 100°C and the reaction was continued for 2 hours, yielding a reaction composition containing the reaction product of pBDEA and jER828. The reaction composition was diluted with benzyl alcohol, a non-reactive diluent, in an amount equivalent to 40% by mass of the total volume, to obtain an epoxy resin curing agent with a concentration of 60% by mass. The active hydrogen equivalent weight (AHEW) of the epoxy resin curing agent (total amount including benzyl alcohol) was 110.3. [Preparation and Evaluation of Epoxy Resin Compositions] A polyfunctional epoxy resin having glycidyloxy groups derived from bisphenol A ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight 186 g / equivalent) was used as the epoxy resin, which is the main component of the epoxy resin composition. The epoxy resin and the epoxy resin curing agent were blended and mixed so that the ratio of the number of active hydrogens in the curing agent to the number of epoxy groups in the epoxy resin (number of active hydrogens in the curing agent / number of epoxy groups in the epoxy resin) was 1 / 1, to prepare an epoxy resin composition. The obtained epoxy resin composition was subjected to various evaluations using the methods described above, and the results are shown in Table 1.

[0049] Example 2 An epoxy resin curing agent was obtained in the same manner as in Example 1, except that 43.3 g of pBDEA-2M obtained in Production Example 2 and 16.7 g of jER828 were used instead of 41.3 g of pBDEA and 18.7 g of jER828 in the "Preparation of epoxy resin curing agent" section of Example 1. Using this epoxy resin curing agent, an epoxy resin composition was prepared in the same manner as in Example 1, and the above-mentioned evaluations were carried out. The results are shown in Table 1.

[0050] Example 3 An epoxy resin curing agent was obtained in the same manner as in Example 1, except that 41.3 g of mBDEA obtained in Production Example 3 was used instead of 41.3 g of pBDEA in Example 1. Using this epoxy resin curing agent, an epoxy resin composition was prepared in the same manner as in Example 1, and the above-mentioned evaluations were carried out. The results are shown in Table 1.

[0051] Comparative Example 1 An epoxy resin curing agent was obtained in the same manner as in Example 1, except that 38.8 g of metaxylylenediamine (MXDA, manufactured by Mitsubishi Gas Chemical Co., Inc.) was used instead of 41.3 g of pBDEA. Using this epoxy resin curing agent, an epoxy resin composition was prepared in the same manner as in Example 1, and the above-mentioned evaluations were carried out. The results are shown in Table 1.

[0052] [Table 1]

[0053] Example 4 An epoxy resin curing agent was obtained in the same manner as in Example 1, except that 2.0 g of pBDEA, 37.0 g of MXDA, and 21.1 g of jER828 were used instead of 41.3 g of pBDEA and 18.7 g of jER828 in Example 1. Using this epoxy resin curing agent, an epoxy resin composition was prepared in the same manner as in Example 1, and the above-mentioned evaluations were carried out. The results are shown in Table 2.

[0054] Example 5 An epoxy resin curing agent was obtained in the same manner as in Example 4, except that the amounts of pBDEA, MXDA, and jER828 were changed to 3.9 g, 35.2 g, and 21.0 g, respectively. Using the obtained epoxy resin curing agent, an epoxy resin composition was prepared in the same manner as in Example 4, and the above-mentioned evaluations were carried out. The results are shown in Table 2.

[0055] Example 6 An epoxy resin curing agent was obtained in the same manner as in Example 4, except that the amounts of pBDEA, MXDA, and jER828 were changed to 5.9 g, 33.3 g, and 20.8 g, respectively. Using the obtained epoxy resin curing agent, an epoxy resin composition was prepared in the same manner as in Example 4, and the above-mentioned evaluations were carried out. The results are shown in Table 2.

[0056] Example 7 An epoxy resin curing agent was obtained in the same manner as in Example 4, except that the amounts of pBDEA, MXDA, and jER828 were changed to 7.86 g, 31.44 g, and 20.7 g, respectively. Using the obtained epoxy resin curing agent, an epoxy resin composition was prepared in the same manner as in Example 4, and the above-mentioned evaluations were carried out. The results are shown in Table 2.

[0057] Example 8 An epoxy resin curing agent was obtained in the same manner as in Example 4, except that the amounts of pBDEA, MXDA, and jER828 were changed to 20.05 g, 20.05 g, and 19.9 g, respectively. Using the obtained epoxy resin curing agent, an epoxy resin composition was prepared in the same manner as in Example 4, and the above-mentioned evaluations were carried out. The results are shown in Table 2.

[0058] [Table 2]

[0059] Example 9 An epoxy resin curing agent was obtained in the same manner as in Example 2, except that 7.94 g of pBDEA-2M, 31.76 g of MXDA, and 20.3 g of jER828 were used instead of 43.3 g of pBDEA-2M and 16.7 g of jER828. Using this epoxy resin curing agent, an epoxy resin composition was prepared in the same manner as in Example 2, and the above-mentioned evaluations were carried out. The results are shown in Table 3.

[0060] Example 10 An epoxy resin curing agent was obtained in the same manner as in Example 9, except that the amounts of pBDEA-2M, MXDA, and jER828 were changed to 20.5 g, 20.5 g, and 19.0 g, respectively. Using the obtained epoxy resin curing agent, an epoxy resin composition was prepared in the same manner as in Example 9, and the above-mentioned evaluations were carried out. The results are shown in Table 3.

[0061] [Table 3]

[0062] Example 11 An epoxy resin curing agent was obtained in the same manner as in Example 3, except that 7.86 g of mBDEA, 31.44 g of MXDA, and 20.7 g of jER828 were used instead of 41.3 g of mBDEA and 18.7 g of jER828. Using this epoxy resin curing agent, an epoxy resin composition was prepared in the same manner as in Example 3, and the above-mentioned evaluations were carried out. The results are shown in Table 4.

[0063] Example 12 An epoxy resin curing agent was obtained in the same manner as in Example 11, except that the amounts of mBDEA, MXDA, and jER828 were changed to 20.05 g, 20.05 g, and 19.9 g, respectively. Using the obtained epoxy resin curing agent, an epoxy resin composition was prepared in the same manner as in Example 11, and the above-mentioned evaluations were carried out. The results are shown in Table 4.

[0064] [Table 4]

[0065] It can be seen from Tables 1 to 4 that the epoxy resin compositions containing the epoxy resin curing agent of the present invention provide coating films with better transparency and weather resistance than those of Comparative Example 1. The curability of the resulting epoxy resin compositions was also good. Furthermore, as shown in Tables 2 to 4, it was found that the epoxy resin compositions using the epoxy resin curing agents of Examples 2, 3, 8, 11 and 12 also provided coating films with improved water resistance compared to Comparative Example 1. [Industrial Applicability]

[0066] According to the present invention, it is possible to provide an epoxy resin curing agent, an epoxy resin composition, and a coating material containing the same, which are capable of forming a coating film having excellent transparency and weather resistance.< / yi>

Claims

1. An epoxy resin curing agent containing an adduct-modified polyamine (A) containing a diamine (A1) represented by the following general formula (1), The epoxy resin curing agent, wherein the adduct modified product is a reaction composition containing a reaction product of the polyamine (A) and an epoxy compound having at least one epoxy group. 【Chemistry 1】 (In formula (1), R １ ~R ８ each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms.

2. 2. The epoxy resin curing agent according to claim 1, wherein the diamine (A1) is at least one selected from the group consisting of diamines represented by the following formulas (1-1) to (1-3): 【Chemistry 2】

3. 3. The epoxy resin curing agent according to claim 1, wherein the content of the diamine (A1) in the polyamine (A) is 5% by mass or more.

4. The epoxy resin curing agent according to any one of claims 1 to 3, wherein the polyamine (A) further contains xylylenediamine.

5. The epoxy resin curing agent according to any one of claims 1 to 4, wherein a total content of the polyamine (A) and its adduct-modified product in all curing agent components contained in the epoxy resin curing agent is 50 mass% or more.

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 paint containing the epoxy resin composition according to claim 6.

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