Emulsion-type epoxy resin curing agent composition and aqueous epoxy resin composition

Abstract

Provided is an emulsion-type epoxy resin curing agent composition that contains component (A): a reaction composition containing a reaction product of xylylenediamine and styrene, component (B): a nonionic emulsifier having an HLB value of 14.0 or more and having an aromatic ring, component (C): a cosolvent, and water. Also provided is an aqueous epoxy resin composition that includes said composition.

Description

Emulsion-type epoxy resin curing agent composition and water-based epoxy resin composition

[0001] The present invention relates to an emulsion-type epoxy resin curing agent composition and an aqueous epoxy resin composition containing the epoxy resin curing agent composition.

[0002] Polyamines and compounds obtained by addition reactions of polyamines with alkenyl compounds, epoxy compounds, etc. are known to be useful as epoxy resin curing agents. Epoxy resin compositions using these epoxy resin curing agents are widely used in the fields of coatings, such as anticorrosion coatings for ships, bridges, and onshore and offshore steel structures; in the fields of civil engineering and construction, such as linings, reinforcements, crack repair materials, sealants, injection materials, primers, screeds, top coats, and FRP reinforcements for concrete structures, building flooring materials, water and sewerage linings, paving materials, and adhesives; in the fields of electrical and electronics, such as die attach materials and insulating sealants; and in the field of fiber-reinforced plastics.

[0003] In the paint industry, there has been a recent trend to reduce volatile organic compounds (VOCs), leading to growing interest in water-based paints, which use water as the main diluent.

[0004] It is known that a water-soluble polyamine is used as an epoxy resin curing agent in an aqueous epoxy resin composition suitable for use as a water-based paint. For example, Patent Document 1 discloses that an aqueous epoxy resin composition containing a water-based epoxy resin and a curing agent composition containing a reaction product of epichlorohydrin and a specified amine compound in a specified ratio has good workability and provides a coating film with excellent adhesion and chemical resistance, particularly excellent saltwater corrosion resistance.

[0005] Emulsion-type curing agents for water-based epoxy resins, in which a water-insoluble polyamine curing agent is dispersed in water, are also known (see, for example, Patent Documents 2 to 4). Generally, emulsion-type curing agents are required to have good emulsion stability in addition to curing performance. Patent Document 2 discloses a method for producing a curing agent suitable for curing aqueous epoxy resin emulsions, which comprises condensing xylylenediamine, aldehydes having 1 to 3 carbon atoms, and phenols having a hydrocarbon group having 4 or more carbon atoms as essential components, and then forming the resulting aqueous emulsion. It is described that the curing agent has excellent stability, curing properties, chemical resistance, coating performance, etc. Patent Document 3 discloses an aqueous dispersion of a modified polyamine containing a nonionic emulsifier containing a block copolymer of polyethylene glycol and polypropylene glycol, and indicates that the dispersion has good emulsion stability. Patent Document 4 discloses an emulsifier composition primarily composed of a compound obtained by reacting a specific polyamide with a specific reactive organic compound, and an epoxy resin curing agent composition containing the emulsifier composition. It is also described that these emulsifier compositions and epoxy resin curing agent compositions exhibit good dispersibility and storage stability when an aqueous epoxy resin composition is prepared, and that the cured product has excellent physical properties such as water resistance.

[0006] International Publication No. 2020 / 110601 Japanese Patent Application Laid-Open No. 48-78254 Japanese Patent Application Laid-Open No. 2005-187757 Japanese Patent Application Laid-Open No. 2007-91976

[0007] However, it has been found that the water-soluble curing agent composition described in Patent Document 1 and the emulsion-type curing agents described in Patent Documents 2 to 4 do not provide a sufficient pot life in the aqueous epoxy resin composition obtained after mixing with the main epoxy resin. For example, Patent Documents 2 and 3 evaluate the emulsion stability of the emulsion-type curing agent alone, but make no mention of the pot life of the aqueous epoxy resin composition obtained by mixing the curing agent with the main epoxy resin.

[0008] An object of the present invention is to provide an emulsion-type epoxy resin curing agent composition which can prepare an aqueous epoxy resin composition having good emulsifiability and a long pot life, and an aqueous epoxy resin composition containing the emulsion-type epoxy resin curing agent composition.

[0009] The present inventors have found that an emulsion-type epoxy resin curing agent composition containing a specific amine-based curing agent, a specific nonionic emulsifier, a cosolvent, and water can solve the above-mentioned problems. Specifically, the present invention relates to the following: [1] An emulsion-type epoxy resin curing agent composition containing: component (A): a reaction composition containing a reaction product of xylylenediamine and styrene; component (B): a nonionic emulsifier having an aromatic ring and an HLB value of 14.0 or more; component (C): a cosolvent; and water. [2] The emulsion-type epoxy resin curing agent composition according to [1], wherein component (B) contains at least one member selected from the group consisting of polyoxyethylene styrenated phenyl ether and an ethylene oxide adduct of an aromatic hydrocarbon formaldehyde resin. [3] The emulsion-type epoxy resin curing agent composition according to [1] or [2], wherein component (C) contains a cosolvent having a hydroxy group. [4] The emulsion-type epoxy resin curing agent composition according to any one of [1] to [3], wherein the content of component (A) in the emulsion-type epoxy resin curing agent composition is 10 to 60% by mass. [5] The emulsion-type epoxy resin curing agent composition according to any one of [1] to [4], wherein the content of component (B) is 0.1 to 20% by mass relative to 100% by mass of the total of components (A) and (B). [6] The emulsion-type epoxy resin curing agent composition according to any one of [1] to [5], wherein the mass ratio of component (C) to the total mass of components (A) and (B) is 0.01 to 3.0. [7] The emulsion-type epoxy resin curing agent composition according to any one of [1] to [6], wherein the emulsion is an oil-in-water emulsion. [8] The emulsion-type epoxy resin curing agent composition according to any one of [1] to [7], wherein the emulsion particle size measured by dynamic light scattering is 1,000 nm or less. [9] An aqueous epoxy resin composition obtained by mixing the emulsion-type epoxy resin curing agent composition according to any one of [1] to [8] with an epoxy resin emulsion.

[10] The aqueous epoxy resin composition according to [9], wherein the epoxy resin in the epoxy resin emulsion contains a solid epoxy resin.

[11] A method for producing the aqueous epoxy resin composition according to [9] or

[10] , comprising the following steps (I) to (III) in this order: step (I): mixing the components (A), (B), and (C) to prepare mixture 1; step (II): adding water to mixture 1 and stirring the mixture to effect phase inversion emulsification, thereby obtaining an emulsion-type epoxy resin curing agent composition; and step (III): mixing the emulsion-type epoxy resin curing agent composition with the epoxy resin emulsion.

[0010] According to the present invention, there can be provided an emulsion-type epoxy resin curing agent composition which can prepare an aqueous epoxy resin composition having good emulsifiability and a long pot life, and an aqueous epoxy resin composition containing the emulsion-type epoxy resin curing agent composition.

[0011] [Definition] In this specification, the term "emulsion-type epoxy resin curing agent composition" refers to an epoxy resin curing agent composition in the form of an emulsion (preferably in the form of an oil-in-water emulsion). The emulsion-type epoxy resin curing agent composition is a composition that does not contain an epoxy resin that is the main component of the epoxy resin composition. The term "epoxy resin that is the main component of the epoxy resin composition" refers to an epoxy resin that is intentionally added as the main component of the epoxy resin composition, and does not include epoxy resins that are unintentionally mixed in as unreacted raw materials, by-products, or impurities contained in the blended components.

[0012] In this specification, the term "waterborne epoxy resin composition" refers to an epoxy resin composition containing at least an epoxy resin as a main component and an epoxy resin curing agent for curing the epoxy resin, and having a water content of preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and still more preferably 30% by mass or more.

[0013] In this specification, the term "reaction composition containing a reactant of X and Y" refers to a composition obtained by reacting X and Y, which contains not only the reactant (adduct) of X and Y, but also by-products other than the reactant, and unreacted raw materials such as X and Y.

[0014] [Emulsion-type epoxy resin curing agent composition] The emulsion-type epoxy resin curing agent composition of the present invention (hereinafter also simply referred to as "curing agent composition (of the present invention)") is an emulsion-type epoxy resin curing agent composition containing: Component (A): a reaction composition containing a reaction product of xylylenediamine and styrene; Component (B): a nonionic emulsifier having an aromatic ring and an HLB value of 14.0 or more; Component (C): a cosolvent; and water. By having the above-mentioned configuration, the curing agent composition of the present invention exhibits the effect of being able to prepare an aqueous epoxy resin composition which has good emulsifiability and a long pot life.

[0015] The reason why the above-mentioned effects are achieved in the present invention is unclear, but is thought to be as follows. The reaction composition used as component (A) is an amine composition containing a styrene-modified xylylenediamine and acts as an amine-based epoxy resin curing agent. Because component (A) is lipophilic, it has low solubility in water, and when made into an emulsion, it can be used as a curing agent for water-based epoxy resins. Components (B) and (C) are used to stably emulsify component (A). The nonionic emulsifier component (B) has an HLB value of 14.0 or higher, which gives it good affinity with water, and the presence of an aromatic ring provides good affinity with component (A). This is thought to result in high emulsification performance of component (A) in water. Furthermore, because component (C) is capable of dissolving components (A) and (B) and also has affinity with water, it is thought that an emulsion-type epoxy resin curing agent composition with high emulsion stability can be easily produced by the phase inversion emulsification method described below. Furthermore, the obtained curing agent composition can maintain high emulsion stability even when mixed with the main epoxy resin emulsion, and therefore it is believed that an aqueous epoxy resin composition with a long pot life can be prepared.

[0016] <Component (A): Reaction Composition Comprising a Reaction Product of Xylylenediamine and Styrene> Component (A) is a reaction composition comprising a reaction product of xylylenediamine and styrene. Component (A) acts as an epoxy resin curing agent. The xylylenediamine used in component (A) is at least one selected from the group consisting of orthoxylylenediamine, metaxylylenediamine, and paraxylylenediamine, preferably at least one selected from the group consisting of metaxylylenediamine and paraxylylenediamine, more preferably metaxylylenediamine, and even more preferably metaxylylenediamine.

[0017] The reaction product of xylylenediamine and styrene may include a reaction product in which xylylenediamine and styrene are added in a 1:1 molar ratio (hereinafter also referred to as the "1:1 adduct"), as well as multi-adducts such as a 1:2 adduct, a 1:3 adduct, or a 1:4 adduct of xylylenediamine and styrene. Of these adducts, the 1:1 adduct of xylylenediamine and styrene has the lowest active hydrogen equivalent. The active hydrogen equivalent (hereinafter also referred to as "AHEW") is the molecular weight per equivalent of active hydrogen that can react with the epoxy resin, which is the main component of the aqueous epoxy resin composition. Therefore, when component (A) contains the 1:1 adduct as the main component, good curing performance can be achieved even when the amount added to the aqueous epoxy resin composition is small.

[0018] From the viewpoint of exhibiting good curing performance, the content of the reaction product (1:1 adduct) formed by addition of xylylenediamine and styrene in a molar ratio of 1:1 in component (A) is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and still more preferably 45% by mass or more, and is 100% by mass or less. The content of the 1:1 adduct in component (A) can be determined by gas chromatography (GC) analysis.

[0019] The active hydrogen equivalent weight (AHEW) of component (A) is preferably 130 or less, more preferably 120 or less, and even more preferably 110 or less, from the viewpoint of exhibiting good curing performance even when incorporated in a small amount into the aqueous epoxy resin composition. Furthermore, from the viewpoint of ease of production, it is preferably 80 or more, more preferably 90 or more. The AHEW of component (A) can be determined, for example, by titration.

[0020] Component (A) can be obtained by reacting xylylenediamine with styrene by a known method. More specifically, it can be obtained by subjecting xylylenediamine and styrene to an addition reaction in the presence of a basic catalyst such as an alkali metal, alkali metal amide (represented by the general formula MNRR', where M is an alkali metal, N is nitrogen, and R and R' are each independently hydrogen or an alkyl group), or alkylated alkali metal, preferably at 50 to 120°C, more preferably 70 to 100°C. In the addition reaction of xylylenediamine and styrene, the amount of the basic catalyst used is preferably 0.1 to 20 mol%, more preferably 0.5 to 15 mol%, even more preferably 1.0 to 12 mol%, and even more preferably 1.5 to 10 mol%, based on 100 mol% of the total amount of the raw material polyamine and styrene used. Furthermore, from the viewpoint of obtaining the 1:1 adduct with high selectivity, the amounts of xylylenediamine and styrene used in the addition reaction are such that the molar ratio of styrene to 1 mole of xylylenediamine is in the range of preferably 0.1 to 5.0 moles, more preferably 0.4 to 3.0 moles, even more preferably 0.5 to 1.5 moles, and still more preferably 0.8 to 1.2 moles.

[0021] As component (A), commercially available products such as "Gaskamine 240" manufactured by Mitsubishi Gas Chemical Co., Ltd. can also be used.

[0022] <Component (B): Aromatic Ring-Containing Nonionic Emulsifier with an HLB Value of 14.0 or More> Component (B) is an aromatic ring-containing nonionic emulsifier with an HLB value of 14.0 or more. Here, HLB (hydrophile-lipophile balance) is a value indicating the affinity of the emulsifier (component (B)) for water and oil, and can be calculated using the Griffin method using the following formula: HLB = 20 × [(Molecular Weight of Hydrophilic Group Contained in Component (B)) / (Molecular Weight of Component (B))]. Examples of the hydrophilic group include a hydroxy group and an ethyleneoxy group (EO).

[0023] From the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life, the HLB of component (B) is preferably 14.0 to 20.0, more preferably 15.0 to 20.0, even more preferably 16.0 to 19.5, still more preferably 17.0 to 19.5, and even more preferably 17.5 to 19.0.

[0024] The nonionic emulsifier, component (B), may contain one or more aromatic rings. The "aromatic ring" referred to here may be either a single ring or a condensed ring, such as a benzene ring, a naphthalene ring, or an anthracene ring, with a benzene ring being preferred. From the viewpoint of further improving emulsifiability, component (B) preferably contains two or more aromatic rings. There is no particular upper limit on the number of aromatic rings, but it is preferably 100 or less, more preferably 50 or less, and even more preferably 30 or less.

[0025] The nonionic emulsifier of component (B) preferably has a polyoxyethylene structure from the viewpoint of achieving an HLB value of 14.0 or more. The average number of moles of oxyethylene units added in component (B) is preferably in the range of 4 to 300, more preferably 5 to 200, and even more preferably 5 to 150, from the viewpoint of achieving an HLB value of 14.0 or more and further improving emulsifiability.

[0026] Examples of the nonionic emulsifier having an aromatic ring and a polyoxyethylene structure, which is used as component (B), include polyoxyethylene aryl ethers such as polyoxyethylene phenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene naphthyl ether, polyoxyethylene bisphenol A ether, and polyoxyethylene bisphenol F ether; polyoxyethylene alkyl aryl ethers such as polyoxyethylene benzyl ether and polyoxyethylene dodecyl phenyl ether; ethylene oxide adducts of aromatic hydrocarbon formaldehyde resins; and ethylene oxide adducts of modified aromatic hydrocarbon formaldehyde resins; and one or more of these may be used. Among the above, from the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life, component (B) preferably comprises at least one selected from the group consisting of polyoxyethylene styrenated phenyl ether, an ethylene oxide adduct of an aromatic hydrocarbon formaldehyde resin, and an ethylene oxide adduct of a modified aromatic hydrocarbon formaldehyde resin, and more preferably comprises at least one selected from the group consisting of polyoxyethylene styrenated phenyl ether and an ethylene oxide adduct of an aromatic hydrocarbon formaldehyde resin.

[0027] (Polyoxyethylene styrenated phenyl ether) In this specification, polyoxyethylene styrenated phenyl ether encompasses various polyoxyethylene styrenated phenyl ethers such as polyoxyethylene monostyrenated phenyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tristyrenated phenyl ether, as well as mixtures thereof. Among these, the polyoxyethylene styrenated phenyl ether preferably comprises at least one selected from the group consisting of polyoxyethylene monostyrenated phenyl ether and polyoxyethylene distyrenated phenyl ether, and more preferably comprises polyoxyethylene distyrenated phenyl ether. As polyoxyethylene styrenated phenyl ethers having an HLB value of 14.0 or more, commercially available products such as "NOIGEN EA-207D" (HLB 18.7) manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. and "BLAUNON TSP-50" (HLB 16.9) manufactured by Aoki Oil & Fat Industries Co., Ltd. can also be used.

[0028] (Ethylene oxide adduct of aromatic hydrocarbon formaldehyde resin) The ethylene oxide adduct of aromatic hydrocarbon formaldehyde resin is a compound obtained by an addition reaction between an aromatic hydrocarbon formaldehyde resin and ethylene oxide.

[0029] [Aromatic Hydrocarbon Formaldehyde Resin] An aromatic hydrocarbon formaldehyde resin is a resin obtained by reacting an aromatic hydrocarbon with formaldehyde. In this specification, the term "aromatic hydrocarbon formaldehyde resin" refers to an unmodified aromatic hydrocarbon formaldehyde resin that is not modified with other functional groups or the like. The aromatic hydrocarbon may be at least one selected from the group consisting of benzene, toluene, xylene, mesitylene, pseudocumene, ethylbenzene, propylbenzene, decylbenzene, cyclohexylbenzene, biphenyl, methylbiphenyl, naphthalene, methylnaphthalene, dimethylnaphthalene, ethylnaphthalene, anthracene, methylanthracene, dimethylanthracene, ethylanthracene, and binaphthyl. Among these, from the viewpoint of improving emulsification properties and preparing an aqueous epoxy resin composition with a long pot life, the aromatic hydrocarbon preferably includes at least one selected from the group consisting of toluene, xylene, mesitylene, and pseudocumene, and more preferably includes xylene.

[0030] As formaldehyde, formalin and paraformaldehyde, which are easily available industrially, as well as compounds that generate formaldehyde, such as trioxane, can be used.

[0031] The aromatic hydrocarbon formaldehyde resin preferably includes at least one selected from the group consisting of a toluene formaldehyde resin obtained by reacting toluene with formaldehyde, a xylene formaldehyde resin obtained by reacting xylene with formaldehyde, a mesitylene formaldehyde resin obtained by reacting mesitylene with formaldehyde, and a pseudocumene formaldehyde resin obtained by reacting pseudocumene with formaldehyde, and more preferably includes a xylene formaldehyde resin.

[0032]

[0044] From the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life, the content of the xylene formaldehyde resin in the aromatic hydrocarbon formaldehyde resin 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, and still more preferably 95% by mass or more, but 100% by mass or less.

[0033] From the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life, the weight average molecular weight (Mw) of the aromatic hydrocarbon formaldehyde resin is preferably 200 to 10,000, more preferably 300 to 8,000, even more preferably 350 to 5,000, still more preferably 400 to 3,000, still more preferably 400 to 1,500, and even more preferably 500 to 1,000, in terms of standard polystyrene. The weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC).

[0034] From the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life, the viscosity of the aromatic hydrocarbon-formaldehyde resin at 25°C is preferably 30 to 30,000 mPa s, more preferably 50 to 20,000 mPa s, even more preferably 100 to 15,000 mPa s, still more preferably 300 to 15,000 mPa s, still more preferably 500 to 10,000 mPa s, still more preferably 1,000 to 10,000 mPa s, still more preferably 2,000 to 10,000 mPa s, and still more preferably 3,000 to 8,000 mPa s. The above viscosity can be measured at 25°C using a rotational viscometer.

[0035] The hydroxyl value (mgKOH / g) of the aromatic hydrocarbon formaldehyde resin is preferably 20 to 150 mgKOH / g, more preferably 25 to 120 mgKOH / g, and even more preferably 30 to 100 mgKOH / g, from the viewpoints of ethylene oxide additivity, improved emulsification ability, and preparation of an aqueous epoxy resin composition with a long pot life. The hydroxyl value can be measured by the method described in JIS K0070-1992.

[0036] The hydroxyl equivalent (g / equivalent) of the aromatic hydrocarbon-formaldehyde resin is preferably 200 to 2,500 g / equivalent, more preferably 500 to 2,000 g / equivalent, even more preferably 800 to 1,800 g / equivalent, and still more preferably 1,000 to 1,500 g / equivalent, from the viewpoints of ethylene oxide additivity, improved emulsification ability, and preparation of an aqueous epoxy resin composition with a long pot life. The hydroxyl equivalent can be determined by measuring the hydroxyl value according to the method described in JIS K0070-1992 and converting the hydroxyl value into a hydroxyl equivalent.

[0037] The aromatic hydrocarbon-formaldehyde resin may be a commercially available product or may be produced by a known method, such as the method described in Japanese Patent Publication No. 37-5747, in which an aromatic hydrocarbon and formaldehyde are subjected to a condensation reaction in the presence of a catalyst.

[0038] Commercially available aromatic hydrocarbon formaldehyde resins include, for example, xylene formaldehyde resins manufactured by Fudow Co., Ltd., such as "Nikanol Y-50," "Nikanol Y-100," "Nikanol Y-300," "Nikanol Y-1000," "Nikanol L," "Nikanol LL," "Nikanol LLL," "Nikanol G," "Nikanol H," and "Nikanol H-80."

[0039] The ethylene oxide adduct of an aromatic hydrocarbon-formaldehyde resin can be obtained by reacting the aromatic hydrocarbon-formaldehyde resin with ethylene oxide in the presence of a basic catalyst under heated and pressurized conditions. More specifically, the aromatic hydrocarbon-formaldehyde resin and the basic catalyst are charged into a reactor equipped with a heating and pressurizing mechanism such as an autoclave, and ethylene oxide is fed thereto to react them under heated and pressurized conditions.

[0040] In the above reaction, the amount of ethylene oxide charged per 100 parts by mass of the aromatic hydrocarbon-formaldehyde resin is preferably 120 to 800 parts by mass, more preferably 150 to 600 parts by mass, even more preferably 180 to 500 parts by mass, still more preferably 200 to 450 parts by mass, even more preferably 250 to 450 parts by mass, and still more preferably 300 to 450 parts by mass, from the viewpoint of adjusting the HLB of the resulting ethylene oxide adduct of the aromatic hydrocarbon-formaldehyde resin to a desired range. That is, the ethylene oxide adduct of the aromatic hydrocarbon-formaldehyde resin is obtained by reacting preferably 120 to 800 parts by mass, more preferably 150 to 600 parts by mass, even more preferably 180 to 500 parts by mass, still more preferably 200 to 450 parts by mass, even more preferably 250 to 450 parts by mass, and still more preferably 300 to 450 parts by mass of ethylene oxide per 100 parts by mass of the aromatic hydrocarbon-formaldehyde resin.

[0041] The basic catalyst used in the reaction can be either an inorganic base or an organic base. Examples of inorganic bases include alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, while examples of organic bases include alkali metal alkoxides such as potassium methoxide and sodium methoxide, and amines such as triethylamine. These bases can be used alone or in combination of two or more. Among the basic catalysts, from the viewpoints of improving reaction efficiency and economy, inorganic bases are preferred, alkali metal hydroxides are more preferred, and potassium hydroxide is even more preferred.

[0042] From the viewpoint of improving the reaction efficiency, the reaction temperature in the above reaction is preferably 100 to 190°C, more preferably 140 to 190°C. The reaction time varies depending on the amount of ethylene oxide used, but is preferably 1 to 30 hours, more preferably 1 to 15 hours, even more preferably 1 to 12 hours, and still more preferably 1 to 7 hours. The reaction time here also includes the feed time of ethylene oxide. The pressure during the above reaction is preferably a pressure exceeding normal pressure (1 atmosphere; 0.1013 MPa), and is preferably in the range of 0.12 to 5 MPa, more preferably 0.15 to 2 MPa, and even more preferably 0.15 to 1 MPa.

[0043] From the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life, the weight-average molecular weight of the ethylene oxide adduct of an aromatic hydrocarbon formaldehyde resin is preferably 1,000 to 100,000, more preferably 2,000 to 50,000, even more preferably 3,000 to 25,000, and still more preferably 4,000 to 20,000, in terms of standard polystyrene. The weight-average molecular weight can be determined by the same method as described above.

[0044] (Ethylene oxide adduct of modified aromatic hydrocarbon-formaldehyde resin) The ethylene oxide adduct of modified aromatic hydrocarbon-formaldehyde resin is a compound obtained by an addition reaction between a modified aromatic hydrocarbon-formaldehyde resin and ethylene oxide.

[0045] [Modified aromatic hydrocarbon formaldehyde resin] The modified aromatic hydrocarbon formaldehyde resin is a resin obtained by modifying the aromatic hydrocarbon formaldehyde resin with a phenol, a polyol, etc. From the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life, the modified aromatic hydrocarbon formaldehyde resin is preferably a resin obtained by modifying an aromatic hydrocarbon formaldehyde resin with a phenol.

[0046] The phenols include naturally occurring phenolic compounds such as phenol, alkylphenols, alkenylphenols, terpene phenols, cardanol, etc. The number of carbon atoms in the alkyl group of the alkylphenol is preferably 1 to 24, more preferably 1 to 18, and the number of carbon atoms in the alkenyl group of the alkenylphenol is preferably 2 to 24, more preferably 2 to 18. Specific examples of phenols include phenol, cresol, ethylphenol (e.g., p-ethylphenol), isopropylphenol (e.g., o-isopropylphenol, p-isopropylphenol), butylphenol (e.g., p-tert-butylphenol, p-sec-butylphenol, o-tert-butylphenol, o-sec-butylphenol), amylphenol (e.g., p-tert-amylphenol, o-tert-amylphenol), p-octylphenol, nonylphenol, p-cumylphenol, decylphenol, undecylphenol, p-dodecylphenol, tridecylphenol, tetradecylphenol, pentadecylphenol, pentadecenylphenol, pentadecadienylphenol, pentadecatrienylphenol, hexadecylphenol, heptadecylphenol, octadecylphenol, octadecenylphenol, terpene phenol, and cardanol, and these may be used alone or in combination. Among the above, the phenols preferably include at least one selected from the group consisting of phenol, cresol, butylphenol, and nonylphenol, more preferably include at least one selected from the group consisting of phenol and butylphenol, and even more preferably include phenol.

[0047] Examples of the polyols include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, trimethylolpropane, and neopentyl glycol, and these may be used alone or in combination of two or more.

[0048] The modified aromatic hydrocarbon-formaldehyde resin can be obtained, for example, by reacting the aromatic hydrocarbon-formaldehyde resin with a phenol or a polyol in the presence of an acid or base catalyst.

[0049] Commercially available modified aromatic hydrocarbon formaldehyde resins can also be used. Examples of commercially available phenol-modified aromatic hydrocarbon formaldehyde resins (phenol-modified aromatic hydrocarbon formaldehyde resins) include alkylphenol-modified xylene formaldehyde resins "GHP-150," "HP-210," and "HP-70," phenol-modified (novolac type) xylene formaldehyde resins "NP-100," "GP-212," "P-100," "GP-200," and "HP-30," and phenol-modified (resol type) xylene formaldehyde resins "PR-1440M," "PR-1440," and "GRL," all manufactured by Fudow Co., Ltd. Commercially available products of aromatic hydrocarbon formaldehyde resins modified with polyols (polyol-modified aromatic hydrocarbon formaldehyde resins) include polyol-modified xylene formaldehyde resin "K-100" manufactured by Fudow Co., Ltd.

[0050] The ethylene oxide adduct of a modified aromatic hydrocarbon-formaldehyde resin can be obtained by reacting a modified aromatic hydrocarbon-formaldehyde resin with ethylene oxide in the same manner as in the production of the ethylene oxide adduct of an aromatic hydrocarbon-formaldehyde resin. The production conditions, weight-average molecular weight, and preferred embodiments thereof are the same as those of the ethylene oxide adduct of an aromatic hydrocarbon-formaldehyde resin.

[0051] <Component (C): Cosolvent> The cosolvent of component (C) is a solvent that is capable of dissolving components (A) and (B) and has affinity for water. From the viewpoint of reducing volatile organic compounds (VOCs) and suppressing volatilization during the production process of component (C) and maintaining good emulsifiability, component (C) comprises a solvent whose boiling point at normal pressure is preferably 120°C or higher, more preferably 150°C or higher, even more preferably 160°C or higher, still more preferably 170°C or higher, and even more preferably 180°C or higher.

[0052] The cosolvent used as component (C) preferably includes a cosolvent having a hydroxy group, from the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life. The cosolvent having a hydroxy group is a cosolvent having at least one hydroxy group, and may have a chain structure or a cyclic structure. From the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life, the cosolvent used as component (C) is preferably a cosolvent having a hydroxy group and a cyclic structure. Specific examples of the cosolvent having a hydroxy group used as component (C) include propylene glycol monomethyl ether (boiling point 120°C), propylene glycol n-propyl ether (boiling point 150°C), propylene glycol n-butyl ether (boiling point 171°C), benzyl alcohol (boiling point 205.3°C), furfuryl alcohol (boiling point 170°C), tetrafurfuryl alcohol (boiling point 178°C), and aromatic hydrocarbon formaldehyde resins, and one or more of these may be used. The aromatic hydrocarbon formaldehyde resin referred to here has the same meaning as the aromatic hydrocarbon formaldehyde resin described for component (B). Commercially available aromatic hydrocarbon formaldehyde resins used as component (C) include xylene formaldehyde resins such as "Nikanol Y-50," "Nikanol Y-100," and "Nikanol Y-300" manufactured by Fudow Co., Ltd.

[0053] Among the above, from the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life, component (C) preferably contains at least one cosolvent having a hydroxy group and a ring structure selected from the group consisting of benzyl alcohol, furfuryl alcohol, tetrafurfuryl alcohol, and aromatic hydrocarbon formaldehyde resins, and more preferably contains benzyl alcohol.

[0054] <Water> The water used in the curing agent composition may be purified water such as distilled water or ion-exchanged water (deionized water), tap water, industrial water, or the like.

[0055] <Epoxy Resin Curing Agent Components Other than Component (A)> The curing agent composition does not exclude the inclusion of epoxy resin curing agent components other than component (A). Examples of epoxy resin curing agent components other than component (A) include compounds having two or more active hydrogen-containing groups capable of reacting with epoxy groups in the base resin used in the aqueous epoxy resin composition. Examples of such epoxy resin curing agent components include amine-based curing agents, phenol-based curing agents, acid anhydride-based curing agents, and hydrazide-based curing agents. However, from the viewpoint of preparing an aqueous epoxy resin composition with a long pot life, the content of component (A) in the epoxy resin curing agent components 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, even more preferably 90% by mass or more, and still more preferably 95% by mass or more, but not more than 100% by mass.

[0056] <Contents> The contents of each component in the emulsion-type epoxy resin curing agent composition are preferably in the following ranges: From the viewpoint of improving curability and emulsification properties, and from the viewpoint of preparing an aqueous epoxy resin composition having a long pot life, the content of component (A) in the curing agent composition is preferably 10 to 60% by mass, more preferably 20 to 60% by mass, even more preferably 30 to 55% by mass, and still more preferably 40 to 55% by mass.

[0057] The content of component (B) in the curing agent composition is preferably 1 to 20% by mass, more preferably 2 to 18% by mass, even more preferably 3 to 15% by mass, still more preferably 3 to 12% by mass, still more preferably 3 to 10% by mass, and still more preferably 4 to 8% by mass, from the viewpoints of improving emulsifiability, preparing an aqueous epoxy resin composition having a long pot life, and maintaining the water resistance and the like of the coating film.

[0058] Furthermore, the content of component (B) in the curing agent composition relative to the total of component (A) and component (B) (100% by mass) is preferably 0.1 to 20% by mass, more preferably 0.5 to 18% by mass, even more preferably 1 to 15% by mass, still more preferably 3 to 15% by mass, and still more preferably 5 to 12% by mass, from the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life.

[0059] The total content of component (A) and component (B) in the curing agent composition is preferably 11 to 70% by mass, more preferably 20 to 65% by mass, even more preferably 30 to 65% by mass, still more preferably 35 to 60% by mass, and even more preferably 40 to 60% by mass, from the viewpoint of improving curability and emulsifiability and preparing an aqueous epoxy resin composition having a long pot life.

[0060] The content of component (C) in the curing agent composition is preferably 2 to 30 mass%, more preferably 3 to 25 mass%, even more preferably 4 to 20 mass%, and still more preferably 5 to 15 mass%, from the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life.

[0061] Furthermore, the mass ratio of component (C) in the curing agent composition relative to the total mass of component (A) and component (B) is preferably 0.01 to 3.0, more preferably 0.05 to 2.0, even more preferably 0.08 to 1.0, still more preferably 0.10 to 0.80, still more preferably 0.12 to 0.50, and still more preferably 0.15 to 0.40, from the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition having a long pot life.

[0062] The total content of components (A) to (C) in the curing agent composition is preferably 15 to 85% by mass, more preferably 20 to 80% by mass, even more preferably 30 to 70% by mass, still more preferably 40 to 65% by mass, and even more preferably 50 to 65% by mass, from the viewpoint of improving curability and emulsifiability and preparing an aqueous epoxy resin composition having a long pot life.

[0063] The content of water in the curing agent composition is preferably 15 to 85% by mass, more preferably 20 to 80% by mass, even more preferably 30 to 70% by mass, still more preferably 35 to 60% by mass, and even more preferably 35 to 50% by mass, from the viewpoint of emulsion stability and preparing an aqueous epoxy resin composition having a long pot life. The content of water in the curing agent composition may be the remainder of components (A) to (C).

[0064] <Other Components> The curing agent composition may further contain other components such as a modifying component such as a filler or a plasticizer, a flow adjusting component such as a thixotropic agent, a leveling agent, a dispersant, an antifoaming agent, or a tackifier depending on the application.

[0065] <Method for producing curing agent composition> The method for producing the emulsion-type epoxy resin curing agent composition is not particularly limited, but from the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition with a long pot life, it is preferable to produce the composition by a method having the following steps (I) and (II) in this order: Step (I): mixing the components (A), (B), and (C) to prepare mixture 1 Step (II): adding water to mixture 1 and stirring the mixture to cause phase inversion emulsification to obtain an emulsion-type epoxy resin curing agent composition Details of steps (I) and (II) will be described later in the section on the method for producing an aqueous epoxy resin composition.

[0066] <Form of Curing Agent Composition> The emulsion in the emulsion-type epoxy resin curing agent composition is preferably an oil-in-water emulsion. That is, the curing agent composition of the present invention is an epoxy resin curing agent composition in which component (A) is emulsified and dispersed in water.

[0067] <Emulsion Particle Size of Curing Agent Composition> From the viewpoint of improving emulsifiability and preparing an aqueous epoxy resin composition with a long pot life, the emulsion particle size of the emulsion-type epoxy resin curing agent composition measured by dynamic light scattering is preferably 1,000 nm or less, more preferably 900 nm or less, even more preferably 800 nm or less, and even more preferably 700 nm or less. The lower limit of the emulsion particle size is not particularly limited, but is preferably 50 nm or more. The emulsion particle size is the volume average particle size (D50) measured by dynamic light scattering, and can be specifically measured by the method described in the Examples. Furthermore, it is preferable that the emulsion particle size at least one day after the production of the curing agent composition is within the above range.

[0068] <AHEW of Curing Agent Composition> The AHEW of the curing agent composition varies depending on the content of component (A) in the composition, but from the viewpoint of improving emulsifiability and handleability, and from the viewpoint of preparing an aqueous epoxy resin composition having a long pot life, it is preferably in the range of 120 to 1,000, more preferably 150 to 800, even more preferably 180 to 600, and still more preferably 200 to 400.

[0069] [Water-based Epoxy Resin Composition] The present invention provides a water-based epoxy resin composition obtained by mixing the emulsion-type epoxy resin curing agent composition with an epoxy resin emulsion. That is, the water-based epoxy resin composition of the present invention is an emulsion-type water-based epoxy resin composition, and preferably the emulsion is an oil-in-water emulsion.

[0070] <Epoxy Resin Emulsion> The epoxy resin emulsion is the main component of the aqueous epoxy resin composition and is an emulsion containing at least an epoxy resin and water. In the following description and examples, the epoxy resin emulsion may be simply referred to as the "main component."

[0071] (Epoxy Resin) The epoxy resin in the epoxy resin emulsion may be any epoxy resin having an epoxy group that reacts with the active hydrogen contained in the epoxy resin curing agent component in the curing agent composition. From the viewpoint of preparing an aqueous epoxy resin composition with a long pot life, the epoxy resin in the epoxy resin emulsion preferably contains a solid epoxy resin, and more preferably contains a solid epoxy resin containing an aromatic ring or an alicyclic structure in the molecule. The solid epoxy resin referred to here is an epoxy resin that is solid at 25°C.

[0072] Specific preferred examples of the epoxy resin used in the epoxy resin emulsion include at least one selected from the group consisting of epoxy resins having a glycidylamino group derived from metaxylylenediamine, epoxy resins having a glycidylamino group derived from 1,3-bis(aminomethyl)cyclohexane, epoxy resins having a glycidylamino group derived from diaminodiphenylmethane, epoxy resins having a glycidylamino group and a glycidyloxy group derived from paraaminophenol, epoxy resins having a glycidyloxy group derived from bisphenol A, epoxy resins having a glycidyloxy group derived from bisphenol F, epoxy resins having a glycidyloxy group derived from hydrogenated bisphenol A, epoxy resins having a glycidyloxy group derived from hydrogenated bisphenol F, epoxy resins having a glycidyloxy group derived from phenol novolac, and epoxy resins having a glycidyloxy group derived from resorcinol.

[0073] Among the above, from the viewpoint of preparing an aqueous epoxy resin composition having a long pot life, the epoxy resin preferably comprises at least one selected from the group consisting of an epoxy resin having a glycidylamino group derived from meta-xylylenediamine, an epoxy resin having a glycidyloxy group derived from bisphenol A, and an epoxy resin having a glycidyloxy group derived from bisphenol F, more preferably at least one selected from the group consisting of an epoxy resin having a glycidyloxy group derived from bisphenol A and an epoxy resin having a glycidyloxy group derived from bisphenol F, and even more preferably an epoxy resin having a glycidyloxy group derived from bisphenol A.

[0074] The epoxy equivalent of the epoxy resin used in the epoxy resin emulsion is preferably 150 g / equivalent or more, more preferably 200 g / equivalent or more, from the viewpoint of preparing an aqueous epoxy resin composition having a long pot life, and is preferably 1000 g / equivalent or less, more preferably 800 g / equivalent or less, even more preferably 800 g / equivalent or less, and still more preferably 600 g / equivalent or less, from the viewpoint of the curability of the resulting aqueous epoxy resin composition.

[0075] The content of the epoxy resin in the epoxy resin emulsion is not particularly limited, but is preferably 30% by mass or more, more preferably 35% by mass or more, and from the viewpoint of emulsion stability, is preferably 80% by mass or less.

[0076] (Emulsifier) ​​The epoxy resin emulsion may further contain an emulsifier. The emulsifier used in the epoxy resin emulsion is not particularly limited as long as it is capable of emulsifying the epoxy resin. Any of nonionic emulsifiers, anionic emulsifiers, cationic emulsifiers, amphoteric emulsifiers, and reactive emulsifiers having a reactive group such as an epoxy group can be used. Among the above, from the viewpoint of preparing an aqueous epoxy resin composition with a long pot life using the curing agent composition of the present invention, the emulsifier used in the epoxy resin emulsion preferably includes at least one selected from the group consisting of nonionic emulsifiers and anionic emulsifiers that do not have a reactive group such as an epoxy group, and more preferably includes a nonionic emulsifier that does not have a reactive group. Examples of the nonionic emulsifier include polyether compounds, ester compounds, and alkanolamide compounds. The emulsifier used in the epoxy resin emulsion may also include the aforementioned component (B). The emulsifiers may be used alone or in combination of two or more.

[0077] When the epoxy resin emulsion contains an emulsifier, the content of the emulsifier in the epoxy resin emulsion is preferably 0.1 to 40 parts by mass, more preferably 0.5 to 30 parts by mass, and even more preferably 1 to 20 parts by mass, per 100 parts by mass of the epoxy resin. When the content of the emulsifier is 0.1 part by mass or more per 100 parts by mass of the epoxy resin, the emulsion stability is improved, and when it is 40 parts by mass or less, the water resistance and other properties of the resulting aqueous epoxy resin composition can be maintained well.

[0078] (Water) The content of water in the epoxy resin emulsion is not particularly limited, but from the viewpoint of emulsion stability and improved handleability, it is preferably 15 to 80 mass %, more preferably 20 to 70 mass %, and even more preferably 25 to 60 mass %.

[0079] As the epoxy resin emulsion, commercially available products such as "Araldite PZ 3961-1" (a water-based emulsion of a solid epoxy resin having a glycidyloxy group derived from bisphenol A) manufactured by HUNTSMAN Advanced Materials can also be used.

[0080] <Mixing Ratio> The aqueous epoxy resin composition is obtained by mixing an emulsion-type epoxy resin curing agent composition with an epoxy resin emulsion. The mixing ratio of the emulsion-type epoxy resin curing agent composition and the epoxy resin emulsion is such that the number of active hydrogens in the epoxy resin curing agent component relative to the number of epoxy groups in the epoxy resin (number of active hydrogens in the epoxy resin curing agent component / number of epoxy groups in the epoxy resin) is preferably 0.5 / 1 to 2 / 1, more preferably 0.6 / 1 to 1.5 / 1, and even more preferably 0.7 / 1 to 1.2 / 1. The term "epoxy resin curing agent component" as used herein includes component (A) and epoxy resin curing agent components other than component (A).

[0081] <Content> From the viewpoint of improving curability and emulsion stability, and from the viewpoint of preparing an aqueous epoxy resin composition having a long pot life, the content of component (A) in the aqueous epoxy resin composition is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, even more preferably 3 to 12% by mass, and still more preferably 5 to 10% by mass.

[0082] The content of the epoxy resin curing agent component in the aqueous epoxy resin composition is preferably 1 to 25% by mass, more preferably 2 to 20% by mass, even more preferably 3 to 15% by mass, and still more preferably 5 to 12% by mass, from the viewpoints of improving curability and emulsion stability, and of preparing an aqueous epoxy resin composition with a long pot life. The "content of the epoxy resin curing agent component" referred to here also includes the content of the component (A).

[0083] The content of the epoxy resin in the aqueous epoxy resin composition is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, even more preferably 30 to 55% by mass, and still more preferably 35 to 50% by mass, from the viewpoint of improving curability and emulsion stability, and from the viewpoint of preparing an aqueous epoxy resin composition having a long pot life.

[0084] The content of component (B) in the aqueous epoxy resin composition is preferably 0.1 to 5 mass%, more preferably 0.2 to 3 mass%, even more preferably 0.4 to 2 mass%, and still more preferably 0.5 to 1.5 mass%, from the viewpoint of improving emulsion stability and preparing an aqueous epoxy resin composition having a long pot life.

[0085] The content of component (C) in the aqueous epoxy resin composition is preferably 0.2 to 10 mass%, more preferably 0.4 to 8 mass%, even more preferably 0.8 to 6 mass%, and still more preferably 1 to 5 mass%, from the viewpoint of improving emulsion stability and preparing an aqueous epoxy resin composition having a long pot life.

[0086] Of the non-volatile components in the aqueous epoxy resin composition, the total content of the epoxy resin curing agent component containing component (A), the epoxy resin, and the emulsifier containing component (B) is preferably 10 to 90 mass %, more preferably 15 to 85 mass %, even more preferably 20 to 80 mass %, and still more preferably 30 to 70 mass %, in terms of preparing an aqueous epoxy resin composition having a long pot life.

[0087]

[0033] From the viewpoint of improving emulsion stability and preparing an aqueous epoxy resin composition with a long pot life, the water content in the aqueous epoxy resin composition is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and even more preferably 30% by mass or more. The upper limit of the water content can be adjusted as appropriate, but is usually 90% by mass or less, preferably 80% by mass or less, and more preferably 70% by mass or less. The water content here refers to the total amount of water contained in the aqueous epoxy resin composition.

[0088] <Other Components> The aqueous epoxy resin composition may further contain other components such as pigments, fillers other than pigments, modifying components such as plasticizers, flow-adjusting components such as thixotropic agents, leveling agents, dispersants, antifoaming agents, and tackifiers depending on the intended use. When the aqueous epoxy resin composition contains a pigment, it can also achieve improved chemical resistance. When the aqueous epoxy resin composition contains a pigment, the content of the pigment in the aqueous epoxy resin composition is preferably 1 to 45% by mass, more preferably 2 to 40% by mass, even more preferably 5 to 35% by mass, and even more preferably 10 to 35% by mass, from the viewpoints of improving colorability and chemical resistance and preparing an aqueous epoxy resin composition with a long pot life.

[0089] Although the aqueous epoxy resin composition of the present invention does not exclude the inclusion of an organic solvent other than component (C), it is preferable that the content of the organic solvent be small. The content of the organic solvent other than component (C) in the aqueous epoxy resin composition is preferably less than 10% by mass, more preferably 8% by mass or less, and even more preferably 6% by mass or less.

[0090] [Method for producing aqueous epoxy resin composition] The method for producing the aqueous epoxy resin composition of the present invention is not particularly limited as long as it includes a step of mixing an emulsion-type epoxy resin curing agent composition with an epoxy resin emulsion, but from the viewpoint of preparing an aqueous epoxy resin composition with a long pot life, it preferably includes the following steps (I) to (III) in this order: Step (I): Mixing the components (A), (B), and (C) to prepare mixture 1; Step (II): Adding water to mixture 1 and stirring the mixture to effect phase inversion emulsification, thereby obtaining an emulsion-type epoxy resin curing agent composition; Step (III): Mixing the emulsion-type epoxy resin curing agent composition with the epoxy resin emulsion.

[0091] <Step (I)> In step (I), the components (A), (B), and (C) are mixed to prepare a mixture 1 containing the components (A), (B), and (C). The components (A) and (B) used in step (I) may be used in a state where the active ingredient amount is 100% by mass, or a solution of component (A) or component (B) may be prepared in advance and used in that state. The order in which the components (A), (B), and (C) are mixed is not particularly limited, and the components (A), (B), and (C) may be simultaneously blended and mixed.

[0092] Mixture 1 can be prepared by mixing using a known stirring device such as a disper. The temperature during preparation of Mixture 1 may be room temperature, typically in the range of 0 to 40°C, and preferably 10 to 35°C. The mixing time during preparation of Mixture 1 is not particularly limited as long as it is within a range in which components (A), (B), and (C) become a homogeneous solution, and is typically selected within a range of 0.5 minutes to 12 hours.

[0093] <Step (II)> In step (II), water is added to the mixture 1 obtained in step (I) and stirred to cause phase inversion emulsification, thereby obtaining an emulsion-type epoxy resin curing agent composition. The addition of water to mixture 1 is preferably carried out while stirring the mixture 1. Water may be added continuously or in portions. When water is added in portions, the number of portions is preferably 2 to 20, more preferably 3 to 15, from the viewpoint of improving emulsion stability and preparing an aqueous epoxy resin composition with a long pot life. The stirring device may be the same as that used in step (I). Also, known emulsification devices such as a high-pressure emulsifier or an ultrasonic emulsifier may be used.

[0094] The temperature during the phase inversion emulsification in step (II) may be room temperature, and is usually in the range of 0 to 40° C., preferably 0 to 35° C. The mixing time during the phase inversion emulsification is not particularly limited, and is usually selected in the range of 0.5 minutes to 12 hours.

[0095] <Step (III)> In step (III), the emulsion-type epoxy resin curing agent composition obtained in step (II) is mixed with the epoxy resin emulsion. The epoxy resin emulsion, which is the main component, is first made into an emulsion state and then mixed with the emulsion-type epoxy resin curing agent composition, thereby preparing an aqueous epoxy resin composition with a longer pot life. The preferred mixing ratio of the emulsion-type epoxy resin curing agent composition and the epoxy resin emulsion is as described in the section on aqueous epoxy resin compositions.

[0096] In the mixing step of step (III), the same stirring device as used in step (I) can be used. The temperature during mixing in step (III) may be room temperature, usually in the range of 0 to 40°C, preferably 10 to 35°C. The mixing time in step (III) is also not particularly limited and is usually selected in the range of 0.5 minutes to 12 hours. Optional components added to the aqueous epoxy resin composition may be added in any step. However, optional components other than water added to the emulsion-type epoxy resin curing agent composition are preferably added in step (I).

[0097] [Cured Product] The present invention can provide a cured product of the aqueous epoxy resin composition. The cured product is obtained by curing the aqueous epoxy resin composition by a known method. The curing conditions for the aqueous epoxy resin composition are appropriately selected depending on the application and form. The form of the cured product is not particularly limited and can be selected depending on the application. For example, when the aqueous epoxy resin composition is a paint, the cured product is usually a film-like cured product.

[0098] [Paint] The present invention provides a paint containing the aqueous epoxy resin composition. By containing the aqueous epoxy resin composition, the paint has a long pot life and excellent workability. Examples of such paints include anticorrosion paints, marine paints, tank paints, pipe interior paints, exterior paints, and floor paints. Anticorrosion paints are used, for example, for painting ships, bridges, buildings such as factories, and other land and sea steel structures.

[0099] The content of the aqueous epoxy resin composition in the coating material 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 may be 100% by mass.

[0100] <Applications> In addition to the above-mentioned coating materials, the aqueous epoxy resin composition of the present invention can be suitably used for adhesives, flooring materials, sealants, polymer cement mortars, gas barrier coatings, primers, screeds, top coats, sealants, crack repair materials, concrete materials, etc.

[0101] 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 epoxy resin curing agent composition and the aqueous epoxy resin composition were evaluated by the following methods.

[0102] (Emulsification) The emulsion-type epoxy resin curing agent compositions shown in Table 1 were produced by the method described below, and the emulsification state was visually observed according to the following criteria. Those rated A or B were considered to be acceptable. <Evaluation criteria> A: Good emulsification state B: Emulsified immediately after production but partially separated after 3 days C: Separated within a few minutes after production D: Separated immediately after production

[0103] (Emulsion particle size) A zeta potential / particle size / molecular weight measurement system ("ELSZ-2000" manufactured by Otsuka Electronics Co., Ltd.) was used as the measurement device. For the emulsion-type epoxy resin curing agent compositions shown in Table 1 (excluding those with an "emulsification ability" rating of C or D) produced by the method described below, the curing agent compositions immediately after production and after standing for one day in a room temperature environment were used as measurement samples, and the measured values ​​of the volume average particle size (D50) measured by dynamic light scattering are shown in Table 1. The measurement range was 0.0006 to 10 μm.

[0104] (Pot Life) The components listed in Table 2 were weighed into a 100 mL disposable cup at 23°C and 50% RH, and mixed with a wooden spatula for approximately 2 minutes to prepare an aqueous epoxy resin composition. The aqueous epoxy resin composition was applied every 30 minutes using the method described below. Evaluation was terminated when the formed coating cracked and film formation became impossible, or when the aqueous epoxy resin composition thickened so much that coating became impossible. The time 30 minutes before that point is shown in Table 2. <Application Method> The aqueous epoxy resin composition was dropped onto a test piece (chemically treated steel plate, "SPCC-SD PB-N144" manufactured by Partec, 70 mm x 150 mm x 0.8 mmt), and applied using a 200 μm applicator.

[0105] Production Example 1 (Comparative Example: Production of MXDA-jER828 Reaction Composition (Epoxy Adduct) Solution) A separable flask with an internal volume of 500 milliliters equipped with a stirrer, thermometer, nitrogen inlet tube, dropping funnel, and condenser was charged with 136 g (1 mole) of metaxylylenediamine (MXDA, manufactured by Mitsubishi Gas Chemical Co., Ltd.), and while stirring under a nitrogen stream, 186 g (an amount such that the number of active hydrogens in metaxylylenediamine / the number of epoxy groups in the epoxy compound = 2 / 1) of a multifunctional epoxy resin having glycidyloxy groups derived from bisphenol A ("jER828" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 186 g / equivalent) was added dropwise over 1 hour. After completion of the dropwise addition, the temperature was raised to 80 ° C. and the reaction was carried out for 2 hours, yielding a MXDA-jER828 reaction composition. Benzyl alcohol was added to the reaction mixture in an amount of 25% by mass to dilute the mixture, thereby obtaining a solution with a reaction composition concentration of 75% by mass. The AHEW of the MXDA-jER828 reaction composition (excluding benzyl alcohol) was 107.

[0106] Production Example 2 (Comparative Example: Production of MXDA-phenol-formaldehyde Mannich reaction composition) A 1-liter flask equipped with a stirrer, thermometer, nitrogen inlet tube, dropping funnel, and condenser was charged with 136 g (1 mol) of metaxylylenediamine (Mitsubishi Gas Chemical Co., Ltd., MXDA) and 113 g (1.2 mol) of phenol, and the temperature was raised to 80 ° C. while stirring under a nitrogen stream. Next, 97 g (1.2 mol) of formalin (37% aqueous solution containing 8% methanol) was added dropwise at 80 ° C. over 1.5 hours, and after completion of the dropwise addition, the temperature was raised to 100 ° C. and the reaction was carried out for 1.5 hours. The temperature was raised to 150 ° C. over 2 hours while distilling off water, and the reaction was carried out at the same temperature for 1 hour to obtain a MXDA-phenol-formaldehyde Mannich reaction composition. The reaction molar ratio of MXDA, phenol, and formaldehyde was MXDA / phenol / formaldehyde=1 / 1.2 / 1.2, and the AHEW of the Mannich reaction composition was 102.

[0107] Production Example 3 (Production of Ethylene Oxide Adduct (1) of Xylene Formaldehyde Resin) A pressure-resistant and heat-resistant vessel equipped with a thermometer, a stirrer, a nitrogen inlet pipe, a condenser, and an alkylene oxide inlet pipe was charged with 100 parts by mass of xylene formaldehyde resin ("Nikanol LL" manufactured by Fudow Co., Ltd., weight average molecular weight: 556, hydroxyl value: 40 mgKOH / g, hydroxyl equivalent: 1320 g / equivalent, viscosity (25°C): 4700 mPa·s) and 0.1 parts by mass of potassium hydroxide, and a reaction was carried out under conditions of a reaction temperature of 155°C and a pressure of 0.2 to 0.4 MPa while intermittently feeding 396 parts by mass of ethylene oxide thereto. After the reaction, acetic acid was added to the reaction solution, and the pH of the reaction solution was adjusted to a range of 6.0 to 6.5 to terminate the reaction, thereby obtaining an ethylene oxide adduct of xylene formaldehyde resin (1) (weight average molecular weight: 6000 to 7000, melting point: 56°C, HLB value: 17.7, average number of moles of oxyethylene units added: 119, state (25°C): solid). In the ethylene oxide adduct of xylene formaldehyde resin, the average number of moles of oxyethylene units added was calculated using the following formula: Average number of moles of oxyethylene units added = (hydroxyl group equivalent of xylene formaldehyde resin (g / equivalent) × amount of ethylene oxide charged (parts by mass)) / (molar mass of ethylene oxide (g / mol) × amount of xylene formaldehyde resin charged (parts by mass)).

[0108] Production Example 4 (Comparative Example: Production of Ethylene Oxide Adduct (2) of Xylene Formaldehyde Resin) In a pressure-resistant and heat-resistant vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, a condenser, and an alkylene oxide inlet tube, 100 parts by mass of xylene formaldehyde resin (Nikanol LL manufactured by Fudow Co., Ltd.) and 0.1 parts by mass of potassium hydroxide were charged, and a reaction was carried out under conditions of a reaction temperature of 155°C and a pressure of 0.2 to 0.4 MPa while intermittently feeding 100 parts by mass of ethylene oxide thereto. After the reaction, acetic acid was added to the reaction liquid, and the pH of the reaction liquid was adjusted to a range of 6.0 to 6.5 to terminate the reaction, thereby obtaining an ethylene oxide adduct (2) of xylene formaldehyde resin (weight average molecular weight: 1750, melting point: 48°C, HLB value: 13.2, average number of moles of oxyethylene units added: 30, state (25°C): solid).

[0109] Example 1-1 (Preparation and Evaluation of Emulsion-Type Epoxy Resin Curing Agent Composition) Component (A) was "Gaskamine 240" (manufactured by Mitsubishi Gas Chemical Company, Inc., AHEW: 103), a reaction composition containing a reaction product of metaxylylenediamine (MXDA) and styrene. Component (B) was the ethylene oxide adduct (1) (HLB: 17.7) of xylene formaldehyde resin obtained in Preparation Example 3. Component (C) was benzyl alcohol. Components (A), (B), and (C) were weighed in the amounts shown in Table 1 and mixed at 2000 rpm using a disper mixer. 4 g of water was added thereto and the mixture was mixed at 1000 rpm for 1 minute. Next, 2 g of water was added and the mixture was mixed at 2000 rpm for 1 minute. This operation was repeated six times to obtain an emulsion-type epoxy resin curing agent composition. The obtained curing agent composition was evaluated for emulsification ability and the emulsion particle size was measured by the above-mentioned methods. The results are shown in Table 1.

[0110] Example 1-2 An emulsion-type epoxy resin curing agent composition was produced and evaluated in the same manner as in Example 1-1, except that polyoxyethylene styrenated phenyl ether ("Noigen EA-207D", manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., HLB: 18.7, amount of active ingredient: 55 mass% (remainder: water)) was used as component (B) instead of the ethylene oxide adduct (1) of xylene formaldehyde resin. The results are shown in Table 1.

[0111] Comparative Example 1-1 An emulsion-type epoxy resin curing agent composition was produced and evaluated in the same manner as in Example 1-1, except that 4 g of water was used instead of 4 g of benzyl alcohol, which is component (C). The results are shown in Table 1.

[0112] Comparative Example 1-2 An emulsion-type epoxy resin curing agent composition was produced and evaluated in the same manner as in Example 1-2, except that 4 g of water was used instead of 4 g of benzyl alcohol, which is component (C). The results are shown in Table 1.

[0113] Comparative Examples 1-3 to 1-8 Emulsion-type epoxy resin curing agent compositions were produced and evaluated in the same manner as in Example 1-1, except that component (B) was replaced with component (B') shown in Table 1. The results are shown in Table 1.

[0114] Comparative Example 1-9 An emulsion-type epoxy resin curing agent composition was produced and evaluated in the same manner as in Example 1-1, except that 24 g (benzyl alcohol content: 6 g) of the MXDA-jER828 reaction composition solution obtained in Production Example 1 was used instead of 18 g of "Gaskamine 240" as component (A). The results are shown in Table 1.

[0115] Comparative Example 1-10 An emulsion-type epoxy resin curing agent composition was produced and evaluated in the same manner as in Example 1-2, except that the Mannich reaction composition obtained in Production Example 2 was used instead of 18 g of "Gaskamine 240" as component (A), and the amounts of components (A) and (B) were changed to those shown in Table 1. The results are shown in Table 1.

[0116]

[0117] The components listed in Table 1 are as follows. The amounts (g) listed in Table 1 are all amounts of active ingredients. <Component (A)> Gaskamine 240: reaction composition containing a reaction product of metaxylylenediamine and styrene, manufactured by Mitsubishi Gas Chemical Company, Inc., AHEW: 103 <Component (A')> MXDA-jER828 reaction composition: active component in the MXDA-jER828 reaction composition (epoxy adduct) solution obtained in Production Example 1 MXDA-phenol-formaldehyde Mannich reaction composition: Mannich reaction composition obtained in Production Example 2, reaction molar ratio (MXDA / phenol / formaldehyde) = 1 / 1.2 / 1.2 <Component (B)> Ethylene oxide adduct of xylene formaldehyde resin (1): ethylene oxide adduct of xylene formaldehyde resin obtained in Production Example 3 Noigen EA-207D: Polyoxyethylene styrenated phenyl ether, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., active ingredient content: 55% by mass (balance: water)

[0118] <Component (B')> Emulgen 120: Polyoxyethylene (12) lauryl ether, manufactured by Kao Corporation Emulgen 123P: Polyoxyethylene (23) lauryl ether, manufactured by Kao Corporation Emulgen 150: Polyoxyethylene (47) lauryl ether, manufactured by Kao Corporation Emulgen 1150S-60: Polyoxyethylene alkyl ether type nonionic emulsifier, active ingredient amount: 60% by mass (balance: water) Emulgen 4085: Polyoxyethylene (85) monotetradecyl ether, manufactured by Kao Corporation Ethylene oxide adduct of xylene formaldehyde resin (2): Ethylene oxide adduct of xylene formaldehyde resin obtained in Production Example 4

[0119] As shown in Table 1, the curing agent compositions of Comparative Examples 1-3 to 1-8, which used a nonionic emulsifier not containing an aromatic ring instead of component (B), all showed poor emulsification properties. The curing agent compositions of Comparative Examples 1-5 and 1-6 were rated "B" for emulsification properties, but the emulsion particle size after one day exceeded 1,000 nm. Below, with regard to the curing agent compositions of Comparative Examples 1-1, 1-2, 1-9, and 1-10, which were rated "A" or "B" for emulsification properties and had emulsion particle sizes of less than 1,000 nm after one day, were used to produce and evaluate aqueous epoxy resin compositions.

[0120] Example 2-1 (Preparation and Evaluation of Waterborne Epoxy Resin Composition) The curing agent composition obtained in Example 1-1 was used as the curing agent composition, and "Araldite PZ 3961-1" (manufactured by HUNTSMAN Advanced Materials, an aqueous emulsion of a solid epoxy resin having a glycidyloxy group derived from bisphenol A) was used as the base agent. The curing agent composition and base agent were mixed in the ratios shown in Table 2 to prepare aqueous epoxy resin compositions having the compositions shown in Table 2. The resulting aqueous epoxy resin compositions were subjected to pot life evaluation using the method described above. The results are shown in Table 2.

[0121] Examples 2-2 to 2-4, Comparative Examples 2-1 to 2-10 Epoxy resin compositions were prepared and evaluated in the same manner as in Example 2-1, except that the curing agent compositions or curing agents shown in Table 2 were used and the curing agent compositions or curing agents were mixed with the main component in the ratios shown in Table 2. The results are shown in Table 2.

[0122] Comparative Examples 2-11 to 2-13 Epoxy resin compositions were prepared and evaluated in the same manner as in Example 2-1, except that the curing agents shown in Table 2 were used and the curing agents, main resin, and water were mixed in the ratios shown in Table 2. The results are shown in Table 2.

[0123]

[0124] The components shown in Table 2 are as follows: The blending amounts (mass %) shown in Table 2 are all actual amounts. <Curing agents> Gaskamine 240: reaction composition containing a reaction product of metaxylylenediamine and styrene, manufactured by Mitsubishi Gas Chemical Company, Inc., AHEW: 103 Gaskamine 328: reaction product of epichlorohydrin and metaxylylenediamine, manufactured by Mitsubishi Gas Chemical Company, Inc., AHEW: 55 1,3-bis(aminomethyl)cyclohexane: manufactured by Mitsubishi Gas Chemical Company, Inc., AHEW: 35.6 <Base resin> Araldite PZ 3961-1: aqueous emulsion of solid epoxy resin having a glycidyloxy group derived from bisphenol A, manufactured by HUNTSMAN Advanced Materials, epoxy equivalent (solid content): 503 g / equivalent, solid content concentration: 53 mass%, water content: 40 mass%, methoxypropanol content: 7 mass%

[0125] From Table 2, it can be seen that the aqueous epoxy resin composition containing the emulsion-type epoxy resin curing agent composition of this example has a longer pot life than the aqueous epoxy resin composition of the comparative example.

[0126] Examples 2-5 to 2-6 (Preparation and Evaluation of Pigment-Containing Waterborne Epoxy Resin Compositions) The curing agent composition obtained in Example 1-1 was used as the curing agent composition, and "Araldite PZ 3961-1" (HUNTSMAN Advanced Materials, an aqueous emulsion of a solid epoxy resin having glycidyloxy groups derived from bisphenol A) was used as the base agent. The components shown in Table 3 were blended and stirred in the amounts shown in Table 3 to disperse the titanium oxide pigment, yielding a pigment-blended base composition 1. The blend amounts (g) and mass% shown in Table 3 are all as is. Next, the curing agent composition obtained in Example 1-1 and base composition 1 were mixed in the proportions shown in Table 4 to prepare waterborne epoxy resin compositions with the compositions shown in Table 4. The resulting waterborne epoxy resin compositions were subjected to pot life evaluation using the method described above. The results are shown in Table 4.

[0127]

[0128] The components used in Table 3 are as follows: *1: "Araldite PZ 3961-1" manufactured by HUNTSMAN Advanced Materials, an aqueous emulsion of a solid epoxy resin having a glycidyloxy group derived from bisphenol A, epoxy equivalent (solid content): 503 g / equivalent, solid content concentration: 53 mass%, water content: 40 mass%, methoxypropanol content: 7 mass% *2: "CR-97" manufactured by Ishihara Sangyo Kaisha, Ltd., white titanium oxide (rutile type), average particle size: 0.25 μm *3: "DisperBYK-2081" manufactured by BYK Japan Co., Ltd. *4: "Disparlon AQ-530S" manufactured by Kusumoto Chemicals Co., Ltd.

[0129]

[0130] As shown in Table 4, the aqueous epoxy resin composition of the present invention can achieve a long pot life even when it contains a pigment.

[0131] According to the present invention, there can be provided an emulsion-type epoxy resin curing agent composition which can prepare an aqueous epoxy resin composition having good emulsifiability and a long pot life, and an aqueous epoxy resin composition containing the emulsion-type epoxy resin curing agent composition.

Claims

1. Component (A): A reaction composition containing the reaction product of xylylenediamine and styrene. Ingredient (B): Nonionic emulsifier having an aromatic ring with an HLB value of 14.0 or higher. Component (C): Co-solvent, and An emulsion-type epoxy resin curing agent composition containing water.

2. The emulsion-type epoxy resin curing agent composition according to claim 1, wherein component (B) comprises at least one selected from the group consisting of polyoxyethylene styrene-derived phenyl ether and ethylene oxide adducts of aromatic hydrocarbon formaldehyde resins.

3. The emulsion-type epoxy resin curing agent composition according to claim 1, comprising the aforementioned component (C) as a cosolvent having a hydroxyl group.

4. The emulsion-type epoxy resin curing agent composition according to claim 1, wherein the content of component (A) in the emulsion-type epoxy resin curing agent composition is 10 to 60% by mass.

5. The emulsion-type epoxy resin curing agent composition according to claim 1, wherein the content of component (B) is 0.1 to 20% by mass relative to 100% by mass of the total of component (A) and component (B).

6. The emulsion-type epoxy resin curing agent composition according to claim 1, wherein the mass ratio of component (C) to the total mass of component (A) and component (B) is 0.01 to 3.

0.

7. The emulsion-type epoxy resin curing agent composition according to claim 1, wherein the emulsion is an oil-in-water emulsion.

8. The emulsion-type epoxy resin curing agent composition according to claim 1, wherein the emulsion particle size measured by dynamic light scattering is 1,000 nm or less.

9. A water-based epoxy resin composition obtained by mixing the emulsion-type epoxy resin curing agent composition according to any one of claims 1 to 8 with an epoxy resin emulsion.

10. The aqueous epoxy resin composition according to claim 9, wherein the epoxy resin in the epoxy resin emulsion includes a solid epoxy resin.

11. A method for producing the aqueous epoxy resin composition according to claim 9, comprising the following steps (I) to (III) in order. Step (I): A step of mixing components (A), (B), and (C) to prepare mixture 1. Step (II): A step in which water is added to the mixture 1 and stirred to perform phase inversion emulsification in order to obtain an emulsion-type epoxy resin curing agent composition. Step (III): A step of mixing the emulsion-type epoxy resin curing agent composition with the epoxy resin emulsion.