Epoxy resin composition and coating

Abstract

The epoxy resin composition contains an epoxy resin (A), an epoxy resin curing agent (B) and a phosphazene compound (C), the total content of the components (A) to (C) in the epoxy resin composition is 85 mass% or more, and the epoxy resin curing agent (B) contains a diamine represented by general formula (1) or a modified product (b1) thereof. (1) NH2-CH2-X-CH2-NH2 (In the formula, X represents a phenylene group or a cyclohexylidene group. )

Description

Technical Field

[0001] The present invention relates to an epoxy resin composition and a coating material. Background Art

[0002] In recent years, wood has been actively used in interior and exterior finishing materials and structural members of public facilities and the like. On the other hand, due to the large scale of public facilities and other buildings and the gathering of an indefinite number of people, the application of fire prevention restrictions according to the Building Standards Law has increased.

[0003] In order to make wood flame retardant, a flame retardant such as a boric acid compound is usually injected for non-combustion treatment. However, the problem has arisen that the flame retardant oozes out of the wood over time, resulting in a phenomenon in which the wood turns white (efflorescence phenomenon). In order to prevent the oozing out of the flame retardant, the non-combustible wood is usually coated, and in order not to impair the flame retardancy, a fireproof coating is required.

[0004] Fireproof coatings are usually opaque substances filled with inorganic substances. On the other hand, from the viewpoint of appearance, it is also strongly desired to leave the wood grain, and a fireproof coating with high transparency is ideal.

[0005] There are known a flame-retardant coating composition and a transparent flame-retardant sheet. For example, Patent Document 1 discloses a flame-retardant coating composition containing a coating agent and a mixture of a specific stabilizer having steric hindrance and an existing flame retardant. Patent Document 2 describes a transparent flame-retardant sheet, which is a fiber-reinforced sheet obtained by impregnating a resin composition containing a cyclic and / or chain phosphazene compound having a specific structure with glycidyloxy groups, a compound having two or more epoxy groups in one molecule, and a carboxylic acid or acid anhydride as a curing agent into glass fibers and curing them. Among them, the difference in refractive index between the cured resin composition and the glass fibers is small, the transparent flame-retardant sheet has little coloring, and has excellent heat resistance, flame retardancy, and transparency.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-522532

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2018-172472 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] However, the transparency of the coating composition was not studied in the disclosed technology of Patent Document 1. An epoxy resin composition for a transparent flame retardant sheet is disclosed in Patent Document 2, but the transparency of the sheet is improved by reducing the difference in refractive index between the cured resin composition and that of glass fiber, and there is still room for improvement in enhancing the transparency of the epoxy resin composition alone.

[0012] An object of the present invention is to provide an epoxy resin composition capable of forming a coating film excellent in transparency and flame retardancy, and a coating material containing the composition.

[0013] Means for Solving the Problem

[0014] The present inventors have found that an epoxy resin composition containing an epoxy resin in a specific amount or more, an epoxy resin curing agent containing a specific diamine or its modified product, and a phosphazene compound can solve the above problems.

[0015] That is, the present invention relates to the following.

[0016] [1] An epoxy resin composition comprising an epoxy resin (A), an epoxy resin curing agent (B), and a phosphazene compound (C), wherein the total content of the components (A) to (C) in the epoxy resin composition is 85% by mass or more, and the epoxy resin curing agent (B) contains a diamine represented by the following general formula (1) or its modified product (b1).

[0017] NH2-CH2-X-CH2-NH2 (1)

[0018] (In the formula, X is a phenylene group or a cyclohexylene group.)

[0019] [2] The epoxy resin composition according to the above [1], wherein the component (b1) contains the diamine represented by the general formula (1) or its styrene-modified product.

[0020] [3] The epoxy resin composition according to the above [1] or [2], wherein X in the general formula (1) is a phenylene group.

[0021] [4] The epoxy resin composition according to any one of the above [1] to [3], wherein the component (C) contains a cyclic phosphazene compound.

[0022] [5] The epoxy resin composition according to the above [4], wherein the cyclic phosphazene compound is a compound represented by the following general formula (2-1).

[0023]

[0024] (In the formula, R 1 ~R 6Each independently represents a fluorine atom, an alkoxy group having 1 to 12 carbon atoms, or an aryloxy group having 6 to 12 carbon atoms which may have a substituent.)

[0025] [6] The epoxy resin composition according to any one of [1] to [5] above, wherein the content of the component (C) in the epoxy resin composition is 0.1 to 10% by mass in terms of the content of phosphorus atoms in the composition.

[0026] [7] A coating material containing the epoxy resin composition according to any one of [1] to [6] above.

[0027] Effects of the Invention

[0028] According to the present invention, an epoxy resin composition capable of forming a coating film excellent in transparency and flame retardancy and a coating material containing the composition can be provided. Detailed Description of the Invention

[0029] [Epoxy Resin Composition]

[0030] The epoxy resin composition of the present invention (hereinafter, also simply referred to as "(the present invention's) composition") contains an epoxy resin (A), an epoxy resin curing agent (B), and a phosphazene compound (C), and the total content of the components (A) to (C) in the epoxy resin composition is 85% by mass or more, and the epoxy resin curing agent (B) contains a diamine represented by the following general formula (1) or a modified product thereof (b1).

[0031] NH2-CH2-X-CH2-NH2(1)

[0032] (In the formula, X is a phenylene group or a cyclohexylene group.)

[0033] Due to having the above-described constitution, the epoxy resin composition of the present invention can form a coating film excellent in transparency and flame retardancy.

[0034] The phosphazene compound as the component (C) contains a phosphorus atom and a nitrogen atom and is known as a compound having flame retardancy. Generally, when a flame retardant is added to a resin composition, the transparency is likely to decrease, but it is relatively easy to ensure transparency with a phosphazene compound. However, in an epoxy resin composition for a coating material, it is still insufficient to use only a phosphazene compound as a flame retardant in order to obtain the transparency of the formed coating film.

[0035] The inventors of the present invention have found that by using an epoxy resin curing agent (B) containing a specific component (b1) and a phosphazene compound in combination in an epoxy resin composition, flame retardancy can be provided without impairing transparency. The reason is not yet clear, but it is considered that the component (b1) has a ring structure and thus contributes to the improvement of flame retardancy. Furthermore, since the component (b1) has good compatibility with the component (C), good transparency and flame retardancy can be obtained. In addition, since the total content of the foregoing components (A) to (C) in the epoxy resin composition is 85% by mass or more, the effects of the present invention can be effectively exerted, and a coating film having more excellent transparency and flame retardancy can be formed.

[0036] <Epoxy resin (A)>

[0037] The epoxy resin (A) as the main component of the epoxy resin composition may be any one of saturated or unsaturated aliphatic compounds, alicyclic compounds, aromatic compounds, and heterocyclic compounds. From the viewpoint of obtaining a coating film having high water resistance and chemical resistance, an epoxy resin containing an aromatic ring or an alicyclic structure in the molecule is preferred.

[0038] Specific examples of the epoxy resin (A) include at least one resin selected from epoxy resins having an epoxypropylamino group derived from m-phenylenediamine, epoxy resins having an epoxypropylamino group derived from p-phenylenediamine, epoxy resins having an epoxypropylamino group derived from 1,3-bis(aminomethyl)cyclohexane, epoxy resins having an epoxypropylamino group derived from 1,4-bis(aminomethyl)cyclohexane, epoxy resins having an epoxypropylamino group derived from diaminodiphenylmethane, epoxy resins having an epoxypropylamino group and / or an epoxypropoxy group derived from p-aminophenol, epoxy resins having an epoxypropoxy group derived from bisphenol A, epoxy resins having an epoxypropoxy group derived from bisphenol F, epoxy resins having an epoxypropoxy group derived from phenol novolac, and epoxy resins having an epoxypropoxy group derived from resorcinol. Two or more of the above epoxy resins may also be used in combination.

[0039] Among the above, from the viewpoint of obtaining a coating film having high transparency, flame retardancy, and chemical resistance, the epoxy resin (A) preferably contains at least one selected from the group consisting of epoxy resins having an epoxypropylamino group derived from m-phenylenediamine, epoxy resins having an epoxypropylamino group derived from p-phenylenediamine, epoxy resins having an epoxypropoxy group derived from bisphenol A, and epoxy resins having an epoxypropoxy group derived from bisphenol F as the main component. From the viewpoints of obtaining a coating film having high transparency, flame retardancy, and chemical resistance, and availability and economy, an epoxy resin having an epoxypropoxy group derived from bisphenol A is more preferably used as the main component.

[0040] It should be noted that the "main component" herein means that other components may be included within the scope not departing from the gist of the present invention, preferably 50 to 100% by mass in total, more preferably 70 to 100% by mass, still more preferably 90 to 100% by mass.

[0041] It should be noted that the epoxy resin (A) can be either a solid epoxy resin or a liquid epoxy resin. The "solid epoxy resin" in the present invention refers to an epoxy resin that is solid at room temperature (25°C), and the "liquid epoxy resin" refers to an epoxy resin that is liquid at room temperature (25°C).

[0042] From the viewpoint of obtaining a coating film with high transparency, flame retardancy, chemical resistance, etc., the epoxy equivalent of the epoxy resin (A) is preferably 150 g / equivalent or more. From the viewpoint of curability, the epoxy equivalent of the epoxy resin (A) is preferably 1000 g / equivalent or less, more preferably 800 g / equivalent or less, still more preferably 500 g / equivalent or less, even more preferably 300 g / equivalent or less, and even more preferably 250 g / equivalent or less.

[0043] <Epoxy resin curing agent (B)>

[0044] The epoxy resin curing agent (B) contains a diamine represented by the following general formula (1) or its modified product (b1).

[0045] NH2-CH2-X-CH2-NH2(1)

[0046] (In the formula, X is a phenylene group or a cyclohexylene group.)

[0047] (The diamine represented by the general formula (1) or its modified product (b1))

[0048] The diamine represented by the aforementioned general formula (1) used as the component (b1) is a compound in which X in the aforementioned formula (1) is a phenylene group or a cyclohexylene group.

[0049] Specifically, in the aforementioned formula (1), X is at least one selected from the group consisting of 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, 1,2-cyclohexylene, 1,3-cyclohexylene, and 1,4-cyclohexylene. From the viewpoint of obtaining a coating film with high transparency, flame retardancy, chemical resistance, etc., X is preferably a phenylene group, more preferably at least one selected from the group consisting of 1,2-phenylene, 1,3-phenylene, and 1,4-phenylene, and still more preferably 1,3-phenylene.

[0050] It should be noted that the cyclohexylene groups in this specification all include cis-forms and trans-forms.

[0051] As specific examples of the diamine represented by the aforementioned general formula (1), phthalic diamine, m-xylene diamine (MXDA), p-xylene diamine (PXDA) and other xylene diamines can be mentioned; bis(aminomethyl)cyclohexanes such as 1,2-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane and 1,4-bis(aminomethyl)cyclohexane.

[0052] Among the above, from the viewpoint of obtaining a coating film with high transparency and flame retardancy, the diamine represented by the aforementioned general formula (1) is preferably xylene diamine, and more preferably m-xylene diamine.

[0053] As the modified product of the diamine represented by the aforementioned general formula (1) used as the component (b1), an epoxy modified product obtained by reacting the diamine represented by the aforementioned general formula (1) with an epoxy compound having at least one epoxy group can be mentioned; a reaction product obtained by reacting the diamine represented by the aforementioned general formula (1) with an unsaturated hydrocarbon compound; a carboxylic acid modified product obtained by reacting the diamine represented by the aforementioned general formula (1) with a carboxylic acid or its derivative; a Mannich modified product obtained by reacting the diamine represented by the aforementioned general formula (1) with a phenol compound and an aldehyde compound; a ketimine obtained by reacting the diamine represented by the aforementioned general formula (1) with a ketone compound; a phosphorus modified product obtained by reacting the diamine represented by the aforementioned general formula (1) with a phosphorus-containing compound, etc. These can be used alone or in combination of two or more.

[0054] As the phosphorus modified product obtained by reacting the diamine represented by the aforementioned general formula (1) with a phosphorus-containing compound, for example, the phosphorus modified product represented by the following general formula (3) can be mentioned.

[0055]

[0056] (In the formula, R 11 represents a hydrocarbon group, and X represents a phenylene group or a cyclohexylene group. n is a number from 1 to 5.)

[0057] As the hydrocarbon group in the aforementioned general formula (3) for R 11 , an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, etc. can be mentioned. From the viewpoint of providing high flame retardancy, R 1 is preferably an aryl group having 6 to 18 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, more preferably an aryl group having 6 to 18 carbon atoms, and further preferably an aryl group having 6 to 10 carbon atoms.

[0058] As the aforementioned aryl group, phenyl, tolyl, mesityl, biphenyl, naphthyl, etc. can be mentioned, and phenyl is preferred.

[0059] X in the aforementioned general formula (3) is the same as the above.

[0060] Among the above, from the viewpoint of obtaining a coating film with high transparency and flame retardancy, as a modified product of the diamine represented by the general formula (1) above, it is preferably at least one selected from the group consisting of an epoxy modified product obtained by reacting the diamine represented by the general formula (1) with an epoxy compound having at least one epoxy group and a reaction product obtained by reacting the diamine represented by the general formula (1) with an unsaturated hydrocarbon compound, and more preferably a reaction product obtained by reacting the diamine represented by the general formula (1) with an unsaturated hydrocarbon compound. It should be noted that the reaction composition mentioned here refers to a composition obtained by reacting the diamine represented by the general formula (1) with an unsaturated hydrocarbon compound and containing at least the reaction product (adduct) of the diamine represented by the general formula (1) with the unsaturated hydrocarbon compound. In addition to the above-mentioned adduct, this reaction composition may also contain unreacted raw materials, by-products, etc.

[0061] Examples of the unsaturated hydrocarbon compound in the reaction product obtained by reacting the diamine represented by the general formula (1) with an unsaturated hydrocarbon compound include unsaturated aliphatic hydrocarbon compounds having 2 to 10 carbon atoms and aromatic hydrocarbon compounds having 2 to 10 carbon atoms with an ethylenic unsaturated bond. For example, at least one selected from the group consisting of ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, isobutene, 2-pentene, 3-methyl-1-butene, 2-methyl-2-butene, 2,3-dimethyl-2-butene, cyclohexene, cyclohexadiene, styrene, and divinylbenzene can be cited.

[0062] Among these, from the viewpoint of obtaining a coating film with high transparency and flame retardancy, as the unsaturated hydrocarbon compound, aromatic hydrocarbon compounds having an ethylenic unsaturated bond such as styrene and divinylbenzene are preferred, and styrene is more preferred. That is, the modified product of the diamine represented by the general formula (1) used as the component (b1) is preferably a reaction product obtained by reacting the diamine represented by the general formula (1) with an aromatic hydrocarbon compound having an ethylenic unsaturated bond, and more preferably a styrene modified product of the diamine represented by the general formula (1).

[0063] From the viewpoint of obtaining a coating film with high transparency and flame retardancy, the component (b1) preferably contains the diamine represented by the general formula (1) or its styrene modified product, more preferably contains at least one selected from the group consisting of xylylenediamine and the styrene modified product of xylylenediamine, further preferably contains at least one selected from the group consisting of m-xylylenediamine and the styrene modified product of m-xylylenediamine, and even more preferably contains m-xylylenediamine.

[0064] From the viewpoint of obtaining a coating film having high transparency and flame retardancy, the content of the diamine represented by the general formula (1) or its styrene-modified product in the component (b1) is preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, still further preferably 70% by mass or more, still further preferably 80% by mass or more, still further preferably 90% by mass or more, and 100% by mass or less.

[0065] From the viewpoint of obtaining a coating film having high transparency and flame retardancy, the content of the component (b1) in the epoxy resin curing agent (B) is preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, still further preferably 70% by mass or more, still further preferably 80% by mass or more, still further preferably 90% by mass or more, and 100% by mass or less.

[0066] (Curing agent component other than component (b1))

[0067] The epoxy resin curing agent (B) may also contain a curing agent component other than the aforementioned component (b1). The curing agent component in this specification refers to a component having two or more active hydrogens capable of reacting with an epoxy group in the epoxy resin, which is contained in the epoxy resin curing agent (B).

[0068] Examples of the curing agent component other than the component (b1) include amine-based curing agents, phenol-based curing agents, acid anhydride-based curing agents, hydrazide-based curing agents, etc., other than the component (b1).

[0069] When using a curing agent component other than the component (b1), the content of the curing agent component in the epoxy resin curing agent (B) is preferably 1% by mass or more, more preferably 5% by mass or more. The upper limit of the content is within a range that does not impair the effects of the present invention, and is preferably 70% by mass or less, more preferably 50% by mass or less, further preferably 40% by mass or less, still further preferably 30% by mass or less, still further preferably 20% by mass or less, still further preferably 10% by mass or less.

[0070] From the viewpoint of obtaining good coating film physical properties, the active hydrogen equivalent of the epoxy resin curing agent (B) is preferably 20 or more, more preferably 30 or more, and from the viewpoint of improving curability, it is preferably 150 or less. The active hydrogen equivalent (hereinafter also referred to as "AHEW") refers to the mass per 1 mole of active hydrogen of the epoxy resin curing agent.

[0071] <Phosphazene compound (C)>

[0072] The phosphazene compound in this specification refers to a compound having a structure in which phosphorus atoms and nitrogen atoms are alternately bonded.

[0073] The phosphazene compound (C) (hereinafter, also simply referred to as "component (C)") can be either a linear phosphazene compound or a cyclic phosphazene compound, and from the viewpoint of obtaining a coating film with high transparency and flame retardancy, a cyclic phosphazene compound is preferably included.

[0074] From the viewpoint of obtaining a coating film with high transparency and flame retardancy, the content of the cyclic phosphazene compound in the phosphazene compound (C) is preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, still further preferably 70% by mass or more, still further preferably 80% by mass or more, still further preferably 90% by mass or more, and 100% by mass or less.

[0075] Examples of the cyclic phosphazene compound include the compound represented by the following general formula (2).

[0076]

[0077] (In the formula, R and R' each independently represent a fluorine atom, an alkoxy group having 1 to 12 carbon atoms, or an aryloxy group having 6 to 12 carbon atoms which may have a substituent. n is a number from 3 to 8.)

[0078] In formula (2), the plurality of R and the plurality of R' may all be the same or may be different from each other. In formula (2), n is preferably from 3 to 6, more preferably from 3 to 4, and further preferably 3.

[0079] Examples of the cyclic phosphazene compound preferably include the compound represented by the following general formula (2-1).

[0080]

[0081] (In the formula, R 1 ~R 6 each independently represent a fluorine atom, an alkoxy group having 1 to 12 carbon atoms, or an aryloxy group having 6 to 12 carbon atoms which may have a substituent.)

[0082] R 1 ~R 6 The alkoxy group in preferably has 1 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, and further preferably 2 to 4 carbon atoms. Specific examples of the preferred alkoxy group include methoxy, ethoxy, various propoxy groups, various butoxy groups, etc. "Various" means including linear and all branched groups, and the same applies hereinafter.

[0083] R 1 ~R 6 The aryloxy group in is -OR 7 (R 7The group shown as (aryl) has substituents optionally on the aromatic ring of the aryl. As such substituents, hydroxyl group, alkoxy groups having 1 to 4 carbon atoms, cyano group, vinyl group, epoxy group-containing groups, etc. can be mentioned, and cyano group is preferred.

[0084] R 1 ~R 6 In, the number of carbon atoms of the aryloxy group is preferably 6 to 10, more preferably 6 to 8.

[0085] In formula (2-1), R 1 ~R 6 is preferably a fluorine atom, an alkoxy group having 1 to 4 carbon atoms, or an aryloxy group having 6 to 12 carbon atoms optionally having a cyano group, more preferably an aryloxy group having 6 to 12 carbon atoms optionally having a cyano group, and further preferably a phenoxy group.

[0086] R 1 ~R 6 may all be the same or may be different from each other, and more preferably all are phenoxy groups.

[0087] As specific examples of the cyclic phosphazene compound used as the phosphazene compound (C), compounds shown by the following formulas (2-2) to (2-5) can be mentioned, and the compound shown by formula (2-2) is preferred.

[0088]

[0089] As the phosphazene compound (C), commercially available products can also be used. As examples of commercially available products, "FP-100" (hexaphenoxycyclotriphosphazene; the compound shown by formula (2-2)), "FP-110", "FP-300B" (the compound shown by formula (2-3)) manufactured by Fushimi Pharmaceutical Co., Ltd., "HISHICOLIN E" (the compound shown by formula (2-4)), "HISHICOLIN O" (the compound shown by formula (2-5)) manufactured by Nippon Chemical Industry Co., Ltd., "SPE-100", "SPB-100", "SPM-100", "SPS-100", etc. manufactured by Otsuka Chemical Co., Ltd.

[0090] <Content>

[0091] In the epoxy resin composition, the ratio of the number of active hydrogens in the epoxy resin curing agent (B) to the number of epoxy groups in the epoxy resin (A) (the number of active hydrogens in the epoxy resin curing agent (B) / the number of epoxy groups in the epoxy resin (A)) is preferably 1 / 0.5 to 1 / 2, more preferably 1 / 0.75 to 1 / 1.5, and further preferably 1 / 0.8 to 1 / 1.2.

[0092] Regarding the content of the epoxy resin (A) in the epoxy resin composition, there is no limitation as long as the aforementioned (number of active hydrogens in the epoxy resin curing agent (B) / number of epoxy groups in the epoxy resin (A)) preferably falls within the above range, and it is preferably 30 to 80% by mass, more preferably 40 to 80% by mass, and further preferably 50 to 75% by mass.

[0093] Regarding the content of the epoxy resin curing agent (B) in the epoxy resin composition, there is no limitation as long as the aforementioned (number of active hydrogens in the epoxy resin curing agent (B) / number of epoxy groups in the epoxy resin (A)) preferably falls within the above range, and it is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and further preferably 10 to 20% by mass.

[0094] From the viewpoint of obtaining a coating film with high transparency and flame retardancy, the content of the phosphazene compound (C) in the epoxy resin composition is preferably 0.1 to 10% by mass, more preferably 0.2 to 8.0% by mass, further preferably 0.5 to 5.0% by mass, still further preferably 0.5 to 2.5% by mass, still further preferably 1.0 to 2.4% by mass, still further preferably 1.0 to 2.2% by mass, based on the content of phosphorus atoms in the composition.

[0095] In addition, from the viewpoint of obtaining a coating film with high transparency and flame retardancy, the content of the phosphazene compound (C) in the epoxy resin composition is preferably 1.0 to 30% by mass, more preferably 2.0 to 30% by mass, further preferably 4.0 to 20% by mass, still further preferably 5.0 to 20% by mass.

[0096] In the epoxy resin composition, depending on the use, it may also contain a curing accelerator, a non-reactive diluent such as benzyl alcohol, a modifying component such as a filler or a plasticizer, a flow regulating component such as a thixotropic agent, a pigment, a leveling agent, a tackifier, an elastomeric particle and other components.

[0097] Among them, from the viewpoint of obtaining a coating film with high transparency, flame retardancy and chemical resistance, the total content of the components (A) to (C) in the epoxy resin composition is 85% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 98% by mass or more, and in addition, it is 100% by mass or less.

[0098] From the viewpoint of obtaining a coating film with high transparency, flame retardancy and chemical resistance, the epoxy resin composition of the present invention preferably has a low content of water and organic solvents.

[0099] From the viewpoint of obtaining a coating film having high transparency, flame retardancy, chemical resistance, etc., the content of water and organic solvents in the epoxy resin composition is preferably 10% by mass or less, more preferably 5.0% by mass or less, still more preferably 3.0% by mass or less, even more preferably 2.0% by mass or less, and even more preferably 1.0% by mass or less.

[0100] From the viewpoint of obtaining a coating film having high transparency, flame retardancy, chemical resistance, etc., the content of thermoplastic resins such as polyphenylene ether in the epoxy resin composition of the present invention is preferably small.

[0101] From the viewpoint of obtaining a coating film having high transparency, flame retardancy, chemical resistance, etc., the content of thermoplastic resins in the epoxy resin composition is preferably 15% by mass or less, more preferably 10% by mass or less, still more preferably 5.0% by mass or less, even more preferably 2.0% by mass or less, and even more preferably 1.0% by mass or less.

[0102] <Method for preparing epoxy resin composition>

[0103] The method for preparing the epoxy resin composition is not particularly limited, and the epoxy resin (A), epoxy resin curing agent (B), phosphazene compound (C) and other components as required can be mixed using known methods and equipment. The mixing order of the components contained in the epoxy resin composition is also not particularly limited. After preparing the aforementioned epoxy resin curing agent (B), it can be mixed with the epoxy resin (A) and the phosphazene compound (C), or the components constituting the epoxy resin curing agent (B) and other components can be mixed with the epoxy resin (A) and the phosphazene compound (C) simultaneously for preparation.

[0104] The coating film of the 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 using a known method. The curing conditions of the epoxy resin composition can be appropriately selected according to the use and form, and are not particularly limited.

[0105] As the coating film of the cured product of the epoxy resin composition of the present invention, it has excellent transparency and flame retardancy, is not easily whitened, and can form a coating film with a high oxygen index.

[0106] <Flame retardancy>

[0107] The epoxy resin composition of the present invention has high flame retardancy. Specifically, it can be measured based on JIS K 7201:1995, and the oxygen index of the cured product of the epoxy resin composition with a thickness of 3 mm is preferably 27 or more, more preferably 28 or more, still more preferably 30 or more, even more preferably 32 or more, and even more preferably 35 or more.

[0108] As one of the indices of flame retardancy, the degree of flame retardancy can be confirmed by measuring the oxygen index. The oxygen index represents the oxygen concentration necessary for combustion to continue. When it exceeds 21, combustion cannot continue in air under normal conditions. In addition, generally, when the oxygen index is 27 or more, it is regarded as indicating high flame retardancy.

[0109] Regarding the oxygen index, specifically, the method described in the examples can be used for measurement.

[0110] [Coating]

[0111] The present invention provides a coating containing the aforementioned epoxy resin composition. Since the coating of the present invention contains the aforementioned epoxy resin composition, the transparency and flame retardancy of the obtained coating film are good. Examples of such coatings include coatings for wood used as interior and exterior finishing materials and structural members of buildings, ship coatings, heavy anti-corrosion coatings, coatings for containers, coatings for interior piping, exterior coatings, coatings for floor materials, and the like.

[0112] From the viewpoint of effectively obtaining the effects of the present invention, the coating according to the present invention is preferably a transparent flame retardant coating.

[0113] From the viewpoint of improving transparency and flame retardancy, the content of the epoxy resin composition in the coating of the present invention is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, still further preferably 90% by mass or more, still further preferably 95% by mass or more, and 100% by mass or less.

[0114] <Usage>

[0115] The use of the aforementioned epoxy resin composition is applicable to the aforementioned coatings, and is also applicable to adhesives, floor materials, sealants, polymer cement mortars, gas barrier coatings, primers, leveling plates, topcoats, sealing materials, crack repair materials, concrete materials, and the like.

[0116] Examples

[0117] Examples and comparative examples are listed below to illustrate the present invention in detail, but the present invention is not limited to the following examples. It should be noted that the evaluation of the epoxy resin composition is carried out according to the following method.

[0118] <Oxygen Index>

[0119] The epoxy resin composition of each example was heated at 80 °C for 1 hour to be cured and formed into a test piece of 70 mm × 6.5 mm × thickness 3 mm.

[0120] Using the above test piece, the oxygen index was measured by the method based on JIS K 7201:1995 using a candle burning tester type D (manufactured by Toyo Seiki Seisaku-sho, Ltd.). The higher the oxygen index, the more excellent the flame retardancy.

[0121] <Appearance of cured product (transparency)>

[0122] The epoxy resin composition was cured by heating at 80 °C for 1 hour in the same manner as the method described in the aforementioned "Oxygen index" to produce a test piece. After 1 day, the appearance of the test piece was visually observed and the transparency was evaluated based on the following criteria. The results are shown in Table 1.

[0123] (Transparency)

[0124] A: No turbidity

[0125] B: Slightly turbid, but no problem in use

[0126] C: Opalescent

[0127] Example 1 (Preparation and evaluation of epoxy resin composition)

[0128] As the epoxy resin (A) as the main component of the epoxy resin composition, a polyfunctional epoxy resin having glycidyloxy groups derived from bisphenol A ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 186 g / equivalent) was used. In addition, as the epoxy resin curing agent (B), m-xylenediamine (MXDA, manufactured by Mitsubishi Gas Chemical Company, Inc.) as the component (b1) was used, and as the phosphazene compound (C), the compound shown in the aforementioned formula (2-2) (hexaphenoxycyclotriphosphazene, "FP-100" manufactured by Fushimi Pharmaceutical Co., Ltd.) was used.

[0129] The aforementioned components (A) to (C) were compounded and mixed so as to be the mass % shown in Table 1, respectively, to prepare an epoxy resin composition. The ratio of the number of active hydrogens in the curing agent (B) to the number of epoxy groups in the epoxy resin (A) (number of active hydrogens in the curing agent (B) / number of epoxy groups in the epoxy resin (A)) was 1 / 1.

[0130] Using the obtained epoxy resin composition, various evaluations were carried out by the aforementioned method. The results are shown in Table 1.

[0131] Comparative Examples 1 to 4

[0132] The components and formulation amounts used in Example 1 were changed as shown in Table 1, and an epoxy resin composition was prepared in the same manner as in Example 1 except for this, and various evaluations were carried out. The results are shown in Table 1.

[0133] [Table 1]

[0134] Table 1

[0135]

[0136] Each component used in Table 1 is as described below.

[0137] *1: A polyfunctional epoxy resin having glycidyloxy groups derived from bisphenol A ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 186 g / equivalent

[0138] *2: m-Xylylenediamine (MXDA, manufactured by Mitsubishi Gas Chemical Company, Inc., AHEW: 34)

[0139] *3: Diethylenetriamine (manufactured by Tokyo Chemical Industry Co., Ltd., AHEW: 20.6)

[0140] *4: The compound represented by the aforementioned formula (2-2) (hexaphenoxycyclotriphosphazene, "FP-100" manufactured by Fushimi Pharmaceutical Co., Ltd., phosphorus atom content: 13.4 mass%)

[0141] *5: A phosphorus-based flame retardant ("Fire Guard FCX-210" manufactured by Teijin Limited, a phosphate ester compound, phosphorus atom content: 15 mass%)

[0142] *6: Polyphenylene ether (PPE, a thermoplastic resin, "IUPIACE PX100L" manufactured by Mitsubishi Engineering-Plastics Corporation)

[0143] As can be seen from Table 1, the cured product of the epoxy resin composition of the present invention has good transparency and flame retardancy.

[0144] Industrial Applicability

[0145] According to the present invention, an epoxy resin composition capable of forming a coating film excellent in transparency and flame retardancy and a coating material containing the composition can be provided.

Claims

1. An epoxy resin composition comprising an epoxy resin A, an epoxy resin curing agent B, and a phosphazene compound C, wherein the total content of components A to C in the epoxy resin composition is 85% by mass or more, and the epoxy resin curing agent B contains a diamine represented by the following general formula (1) or its modified product b1. NH2-CH2-X-CH2-NH2(1) In the formula, X is a phenylene group or a cyclohexylene group.

2. The epoxy resin composition according to claim 1, wherein, The component b1 contains the diamine represented by the general formula (1) or its styrene-modified product.

3. The epoxy resin composition according to claim 1 or 2, wherein X in the general formula (1) is a phenylene group.

4. The epoxy resin composition according to any one of claims 1 to 3, wherein, The component C contains a cyclic phosphazene compound.

5. The epoxy resin composition according to claim 4, wherein The cyclic phosphazene compound is a compound represented by the following general formula (2-1). In the formula, R 1 ~R 6 each independently represents a fluorine atom, an alkoxy group having 1 to 12 carbon atoms, or an aryloxy group having 6 to 12 carbon atoms which may optionally have a substituent.

6. The epoxy resin composition according to any one of claims 1 to 5, wherein, The content of the component C in the epoxy resin composition is 0.1 to 10% by mass based on the content of phosphorus atoms in the composition.

7. A coating material containing the epoxy resin composition according to any one of claims 1 to 6.

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