Aqueous epoxy resin composition, coating material, and article

Abstract

To provide an aqueous epoxy resin composition which enables formation of a cured coating film having excellent storage stability and excellent anticorrosion property and metal adhesion, a coating material containing the aqueous epoxy resin composition, and an article having the cured coating film of the coating material.SOLUTION: An aqueous epoxy resin composition contains an aqueous resin (A) using an epoxy resin (a1), a polybasic acid anhydride (a2), and polyalkylene glycol (a3) having a number average molecular weight of 1,000 to 6,000, as essential reaction raw materials, in a mass ratio represented by [(a2)+(a3)] / (a1) of 2 to 12, an epoxy resin (B) containing a bisphenol A epoxy resin, and an aqueous medium (C), wherein a mass ratio [(B) / (A)] of the aqueous resin (A) to the epoxy resin (B) is 10 to 30.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an aqueous epoxy resin composition, a coating, and an article. [Background technology]

[0002] In general, epoxy resin compositions have excellent mechanical and electrical properties, and can produce cured products with good adhesiveness, solvent resistance, water resistance, heat resistance, etc., and are therefore widely used as insulating materials for electrical and electronic components, adhesives, paints, and for civil engineering and construction purposes.

[0003] Among these applications, solvent-diluted types using various organic solvents have been common, particularly in coating applications, etc. However, in recent years, with a view to protecting the global environment, including preventing air pollution and improving the working environment, there has been a trend toward implementing total volume restrictions on volatile organic compounds (VOCs), and water-based epoxy resin compositions that do not use organic solvents have been attracting attention.

[0004] Known examples of the aqueous epoxy resin composition include an aqueous epoxy resin composition obtained by first reacting polyethylene glycol with trimellitic anhydride, then reacting it with an excess of epoxy resin to synthesize an emulsifier, adding the emulsifier to the epoxy resin, and then adding water (see, for example, Patent Document 1).Also known is an aqueous epoxy resin composition obtained by first reacting polyethylene glycol with an acid anhydride, then reacting it with an excess of epoxy resin to synthesize and extract an emulsifier, then adding the emulsifier to the epoxy resin, and then adding water (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Chinese Patent Application Publication No. 105801868 [Patent Document 2] Chinese Patent Application Publication No. 108503846 Summary of the Invention [Problem to be solved by the invention]

[0006] However, these aqueous epoxy resin compositions have insufficient storage stability, and also have room for improvement in the physical properties of the cured products (e.g., corrosion resistance and metal adhesion) in order to satisfy increasingly high performance requirements in recent years.

[0007] The problem to be solved by the present invention is to provide an aqueous epoxy resin composition which has excellent storage stability and is capable of forming a cured coating film having excellent corrosion resistance and metal adhesion, a paint containing the aqueous epoxy resin composition, and an article having a cured coating film of the paint. [Means for solving the problem]

[0008] As a result of intensive investigations into solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using an aqueous epoxy resin composition containing an aqueous resin using an epoxy resin, a polybasic acid anhydride, and a polyalkylene glycol in specific proportions, an epoxy resin containing a bisphenol A type epoxy resin, and an aqueous medium in specific proportions, and have completed the present invention.

[0009] That is, the present invention provides a process for producing a polyolefin copolymer by reacting an epoxy resin (a1), a polybasic acid anhydride (a2), and a polyalkylene glycol (a3) ​​having a number average molecular weight of 1,000 to 6,000 as essential reaction raw materials, an aqueous resin (A) used in a mass ratio represented by [(a2)+(a3)] / (a1) in the range of 2 to 12; an epoxy resin (B) containing a bisphenol A type epoxy resin; and an aqueous medium (C), The present invention provides an aqueous epoxy resin composition in which the mass ratio of the aqueous resin (A) to the epoxy resin (B) [(B) / (A)] is in the range of 10 to 30, a paint using the same, and an article having a coating film made of the paint. [Effects of the Invention]

[0010] The aqueous epoxy resin composition of the present invention has excellent storage stability, and a paint containing the aqueous epoxy resin composition has excellent corrosion resistance and metal adhesion, and therefore can be suitably used particularly as an anticorrosion paint. DETAILED DESCRIPTION OF THE INVENTION

[0011] The aqueous epoxy resin composition of the present invention comprises, as essential reaction raw materials, an epoxy resin (a1), a polybasic acid anhydride (a2), and a polyalkylene glycol (a3) ​​having a number average molecular weight of 1,000 to 6,000, an aqueous resin (A) used in a mass ratio represented by [(a2)+(a3)] / (a1) in the range of 2 to 12; an epoxy resin (B) containing a bisphenol A type epoxy resin; and an aqueous medium (C), The mass ratio of the aqueous resin (A) to the epoxy resin (B) [(B) / (A)] is in the range of 10-30.

[0012] The aqueous resin (A) of the present invention is characterized in that the essential raw materials are an epoxy resin (a1), a polybasic acid anhydride (a2), and a polyalkylene glycol (a3) ​​having a number average molecular weight of 1,000 to 6,000, and that the amount of these materials used is in the range of 2 to 12 as a mass ratio represented by [(a2) + (a3)] / (a1).

[0013] The aqueous resin (A) may be liquid or solid at room temperature (25°C), and is not particularly limited as long as it can be diluted with the aqueous medium (C) described below. The epoxy equivalent of the aqueous resin (A) is also not particularly limited, but is preferably in the range of 1,000 to 5,000 g / eq., particularly 1,200 to 4,000 g / eq., from the viewpoints of the corrosion resistance of the resulting cured coating film and the reactivity with the curing agent described below.

[0014] Examples of the epoxy resin (a1) include bisphenol-type epoxy resins, hydrogenated bisphenol-type epoxy resins, biphenol-type epoxy resins, hydrogenated biphenol-type epoxy resins, phenylene ether-type epoxy resins, naphthalene-type epoxy resins, naphthylene ether-type epoxy resins, triphenylmethane-type epoxy resins, phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, bisphenol novolac-type epoxy resins, naphthol novolac-type epoxy resins, naphthol-phenol co-condensed novolac-type epoxy resins, naphthol-cresol co-condensed novolac-type epoxy resins, phenol aralkyl-type epoxy resins, naphthol aralkyl-type epoxy resins, dicyclopentadiene-type epoxy resins, biphenyl aralkyl-type epoxy resins, fluorene-type epoxy resins, xanthene-type epoxy resins, dihydroxybenzene-type epoxy resins, trihydroxybenzene-type epoxy resins, oxazolidone-type epoxy resins, and rubber-modified epoxy resins. These epoxy resins can be used alone or in combination of two or more.

[0015] Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol AP type epoxy resin, bisphenol B type epoxy resin, bisphenol BP type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin.

[0016] Examples of the hydrogenated bisphenol type epoxy resin include hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol B type epoxy resin, hydrogenated bisphenol E type epoxy resin, hydrogenated bisphenol F type epoxy resin, and hydrogenated bisphenol S type epoxy resin.

[0017] Examples of the biphenol type epoxy resin include 4,4'-biphenol type epoxy resin, 2,2'-biphenol type epoxy resin, tetramethyl-4,4'-biphenol type epoxy resin, and tetramethyl-2,2'-biphenol type epoxy resin.

[0018] Examples of the hydrogenated biphenol type epoxy resin include hydrogenated 4,4'-biphenol type epoxy resin, hydrogenated 2,2'-biphenol type epoxy resin, hydrogenated tetramethyl-4,4'-biphenol type epoxy resin, and hydrogenated tetramethyl-2,2'-biphenol type epoxy resin.

[0019] Among these, from the viewpoint of ease of obtaining the aqueous resin (A) of the present invention and from the viewpoint of the corrosion resistance and metal adhesion of the coating film obtained from the aqueous epoxy resin composition of the present invention, a liquid epoxy resin having an epoxy equivalent in the range of 155 to 250 g / eq. is preferred, and a bisphenol-type epoxy resin is particularly preferred, with a bisphenol F-type epoxy resin being most preferred.

[0020] The proportion of the epoxy resin (a1) used is preferably within a range of 8 to 30 mass % in the raw materials (reaction raw materials) of the aqueous resin (A).

[0021] Examples of the polybasic acid anhydride (a2) include aliphatic polybasic acid anhydrides, alicyclic polybasic acid anhydrides, aromatic polybasic acid anhydrides, acid halides of aliphatic polybasic acid anhydrides, acid halides of alicyclic polybasic acid anhydrides, and acid halides of aromatic polybasic acid anhydrides.

[0022] Examples of the aliphatic polybasic acid anhydrides include acid anhydrides of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, 1,2,3,4-butanetetracarboxylic acid, etc. Furthermore, the aliphatic hydrocarbon group of the aliphatic polybasic acid anhydride may be either linear or branched, and may have an unsaturated bond in the structure.

[0023] In the present invention, the alicyclic polybasic acid anhydride is one in which an acid anhydride group is bonded to an alicyclic structure, and the presence or absence of an aromatic ring in other structural positions is not important. Examples of the alicyclic polybasic acid anhydride include tetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, cyclohexanetricarboxylic acid, cyclohexanetetracarboxylic acid, bicyclo[2.2.1]heptane-2,3-dicarboxylic acid, methylbicyclo[2.2.1]heptane-2,3-dicarboxylic acid, and 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydrides.

[0024] Examples of the aromatic polybasic acid anhydride include acid anhydrides of phthalic acid, trimellitic acid, pyromellitic acid, naphthalenedicarboxylic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, biphenyldicarboxylic acid, biphenyltricarboxylic acid, biphenyltetracarboxylic acid, and benzophenonetetracarboxylic acid.

[0025] These polybasic acid anhydrides (a2) can be used alone or in combination of two or more. Among these, hexahydrophthalic anhydride is preferred because it can provide an aqueous epoxy resin composition that has excellent storage stability and is capable of forming a cured coating film that has excellent corrosion resistance and metal adhesion.

[0026] The proportion of the polybasic acid anhydride (a2) used is preferably within a range of 4 to 14 mass % in the raw materials (reaction raw materials) for the aqueous resin (A).

[0027] Examples of the polyalkylene glycol (a3) ​​include polyethylene glycol and polypropylene glycol. These polyalkylene glycols can be used alone or in combination of two or more. From the viewpoint of the storage stability of the resulting aqueous epoxy resin composition, polyethylene glycol is preferred.

[0028] The polyalkylene glycol (a3) ​​must have a number average molecular weight in the range of 1,000 to 6,000, preferably 2,000 to 6,000, in order to obtain an aqueous epoxy resin composition that has excellent storage stability and is capable of forming a cured coating film having excellent corrosion resistance and metal adhesion.

[0029] The amount of the polyalkylene glycol (a3) ​​used is preferably in the range of 60 to 88 mass % in the raw materials (reaction raw materials) of the aqueous resin (A).

[0030] The mass ratio [(a2)+(a3)] / (a1)] of the epoxy resin (a1), the polybasic acid anhydride (a2), and the polyalkylene glycol (a3) ​​must be in the range of 2 to 12, since this provides an aqueous epoxy resin composition that has excellent storage stability and is capable of forming a cured coating film having excellent corrosion resistance and metal adhesion. From the viewpoint of further demonstrating these effects, the mass ratio is preferably in the range of 3 to 10.

[0031] The method for producing the aqueous resin (A) is not particularly limited, and any method may be used. For example, the aqueous resin (A) may be produced by reacting all of the reaction raw materials containing the epoxy resin (a1), the polybasic acid anhydride (a2), and the polyalkylene glycol (a3) ​​at once, or by reacting the reaction raw materials sequentially.

[0032] Examples of the method for reacting the reaction raw materials sequentially include a method in which the polyalkylene glycol (a3) ​​and the polybasic acid anhydride (a2) are reacted for 3 to 5 hours at a temperature in the range of 100 to 150° C., and then the epoxy resin (a1) is reacted at a temperature in the range of 100 to 150° C. If the reaction temperature is 100° C. or higher, the reaction does not take an excessively long time and workability is good, while if the reaction temperature is 150° C. or lower, discoloration of the resulting resin is unlikely to occur, and this is preferred.

[0033] A catalyst may be added to promote the reaction. Examples of the catalyst include phosphines such as triphenylphosphine, tertiary amines such as triethylamine, and quaternary ammonium salts. The amount of the catalyst used is not particularly limited, but may be, for example, 0.1 to 3% by mass based on the total mass of the reaction raw materials, namely, the epoxy resin (a1), the polybasic acid anhydride (a2), and the polyalkylene glycol (a3).

[0034] The epoxy resin (B) used in the present invention contains a bisphenol A type epoxy resin from the viewpoint of imparting excellent corrosion resistance to the resulting coating film. The epoxy equivalent of the epoxy resin (B) is preferably in the range of 250 to 600 g / eq., particularly preferably in the range of 300 to 500 g / eq., from the viewpoints of reactivity with the curing agent described below, and the corrosion resistance and metal adhesion of the resulting coating film.

[0035] As the epoxy resin (B), an epoxy resin other than the bisphenol A type epoxy resin (hereinafter, sometimes referred to as "other epoxy resin") can also be used in combination.

[0036] As the other epoxy resin, the same ones as those exemplified as the above-mentioned epoxy resin (a1) (excluding bisphenol A-type epoxy resins) can be used, and two or more of the other epoxy resins can be used in combination. Furthermore, as the other epoxy resin, rubber-modified epoxy resins, dicyclopentadiene-type epoxy resins, and phenol novolac-type epoxy resins are preferred, since they can provide an aqueous epoxy resin composition that has excellent storage stability and is capable of forming a cured coating film having excellent corrosion resistance and metal adhesion.

[0037] The content of the bisphenol A type epoxy resin in the epoxy resin (B) is preferably 40% by mass or more, more preferably 40 to 100% by mass, and particularly preferably 40 to 70% by mass, in order to obtain an aqueous epoxy resin composition capable of forming a cured coating film having excellent corrosion resistance. Note that the epoxy equivalent of the epoxy resin (B) refers to the epoxy equivalent of the epoxy resin (B) when other epoxy resins are used in combination.

[0038] Examples of the aqueous medium (C) include ion-exchanged water, distilled water, etc. These aqueous media can be used alone or in combination of two or more.

[0039] The method for producing the aqueous epoxy resin composition of the present invention is not particularly limited, and any method may be used. For example, the aqueous epoxy resin composition may be obtained by mixing the aqueous resin (A), the epoxy resin (B), and the aqueous medium (C). In this case, the mass ratio [(B) / (A)] of the aqueous resin (A) to the epoxy resin (B) must be in the range of 10 to 30, from the viewpoints of the storage stability of the resulting aqueous epoxy resin composition and the corrosion resistance and metal adhesion of the resulting coating film, and it is particularly preferable that the mass ratio be in the range of 11 to 27.

[0040] Examples of methods for mixing the aqueous resin (A), the epoxy resin (B), and the aqueous medium (C) include methods using a reaction vessel equipped with a stirring blade; kneading machines such as a kneader, continuous kneader, taper roll, single-screw extruder, twin-screw extruder, triple-screw extruder, universal mixer, plastomill, and hand mixer; rotary dispersion mixers such as a homomixer, static mixer, FILMICS, EBARA MILDER, CLEARMIX, ULTRA-TURRAX, CAVItron, and Biomixer; ultrasonic dispersion devices; and devices that have no moving parts and can mix by the flow of the fluid itself, such as an in-line mixer.

[0041] In the method for producing the aqueous epoxy resin composition, an organic solvent may be used before adding the aqueous medium (C) or simultaneously with the aqueous medium (C). The organic solvent does not necessarily have to be a water-soluble solvent, and is not particularly limited as long as it can dissolve the resin of the reaction product and is inert to the resin during use. Examples of the organic solvent include ester compounds such as ethyl acetate, 3-methoxybutyl acetate, methoxypropyl acetate, and cellosolve acetate; alcohol compounds such as methanol, ethanol, and isopropanol; cellosolve compounds such as methyl cellosolve, ethyl cellosolve, propyl cellosolve, normal butyl cellosolve, isobutyl cellosolve, and tert-butyl cellosolve; glyme compounds such as monoglyme, diglyme, and triglyme; propylene glycol monoalkyl ether compounds such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monoisobutyl ether, and propylene glycol mono-tert-butyl ether; and ketone compounds such as acetone and methyl ethyl ketone. These organic solvents may be used alone or in combination of two or more. Among these, cellosolve compounds, propylene glycol monoalkyl ether compounds, and ketone compounds are preferred.

[0042] The organic solvent may remain in the aqueous epoxy resin composition or may be distilled off under reduced pressure. The aqueous epoxy resin composition of the present invention may contain a medium other than the aqueous medium (C), such as an organic solvent that has not been completely distilled off or a liquid medium contained in other components used when the aqueous epoxy resin composition is made into a paint as described below. However, as mentioned above, it is preferable that the aqueous epoxy resin composition does not contain volatile organic compounds (VOCs) from the viewpoint of protecting the global environment.

[0043] In the aqueous epoxy resin composition of the present invention, the epoxy resin (B) is considered to be present as particles in the aqueous medium (C) in a state where it is enveloped in the aqueous resin (A). Therefore, the particle size can be measured, for example, by the method described in the Examples, and the 50% cumulative particle size (hereinafter referred to as d50 particle size) is preferably in the range of 0.3 to 0.8 μm from the viewpoint of storage stability.

[0044] The nonvolatile content of the aqueous epoxy resin composition of the present invention is not particularly limited and can be appropriately determined depending on the ease of mixing with other components when used as a coating material (described later), the coating method after preparation, and the thickness of the coating film. From the viewpoint of workability, it is preferable to adjust the nonvolatile content to 40 to 70 mass%. For example, a viscosity at 25°C (measured using a rotational viscometer, hereinafter referred to as B-type viscosity) in the range of 500 to 8,000 mPa·s is preferred from the viewpoints of workability and storage stability.

[0045] The aqueous epoxy resin composition of the present invention may further contain a curing agent, if necessary.

[0046] As the curing agent, any of those conventionally known as curing agents for epoxy resins can be used, but particularly when preparing for use in coating materials, examples of the curing agent include basic curing agents.

[0047] Examples of the basic curing agent include aliphatic polyamines, alicyclic polyamines, Mannich bases, amine-epoxy addition products, polyamide polyamines, liquid aromatic polyamines, etc. These curing agents can be used alone or in combination of two or more.

[0048] Examples of the aliphatic polyamines include polyalkylene polyamines such as diethylenetriamine, triethylenetriamine, tetraethylenepentamine, and 1,4-bis-(3-aminopropyl)piperazine, m-xylenediamine, and p-xylenediamine.

[0049] Examples of the alicyclic polyamine include 1,2-diaminocyclohexane, 1,4-diamino-3,6-diethylcyclohexene, and isophoronediamine.

[0050] Examples of the Mannich base include condensation reaction products of (1) polyamines such as triethylenetriamine, isophoronediamine, m-xylenediamine, and p-xylenediamine, (2) aldehydes such as formaldehyde, and (3) phenols such as monovalent or polyvalent cresols and xylenols, p-tert-butylphenol, and resorcinol, each having at least one aldehyde-reactive site in the nucleus.

[0051] Examples of the amine-epoxy addition products include (1) reaction products of (a) polyamines such as triethylenetriamine, tetraethylenepentamine, isophoronediamine, m-xylenediamine, and p-xylenediamine with (b) epoxy resins such as glycidyl ethers, including phenyl glycidyl ether, butyl glycidyl ether, diglycidyl ether of bisphenol A, and diglycidyl ether of bisphenol F, and (2) reaction products of the above polyamines with glycidyl esters such as "Cardura E" (registered trademark: Mitsubishi Chemical Group Corporation).

[0052] The polyamide polyamine may be one obtained by reacting a polyamine with a polycarboxylic acid or a dimerized fatty acid, and examples thereof include a reaction product of ethylenediamine with a dimer acid.

[0053] Examples of the liquid aromatic polyamine include reaction products of aromatic polyamines with glycidyl ethers or glycidyl esters. Examples of the aromatic polyamine include diaminodiphenylmethane and diaminodiphenyl sulfone. Examples of the glycidyl ethers include phenyl glycidyl ether, butyl glycidyl ether, diglycidyl ether of bisphenol A, and diglycidyl ether of bisphenol F. Examples of the glycidyl esters include "Cardura E."

[0054] Furthermore, mono-, di-, or triamine compounds having a polyalkylene oxide skeleton can also be used as the curing agent. Examples of commercially available products include "Jeffamine M-1000," "Jeffamine M-2070," "Jeffamine M-3085," "Jeffamine D-230," "Jeffamine D-400," "Jeffamine D-2000," "Jeffamine ED-2003," "Jeffamine T-403," and "Jeffamine T-3000," all manufactured by Huntsman.

[0055] Furthermore, in order to improve the miscibility with the aqueous epoxy resin composition of the present invention, the curing agent may be water-soluble or neutralized with an organic acid and dispersed in a water-based medium, such as "LUCKAMIDE WN-720" manufactured by DIC Corporation.

[0056] The amount of the curing agent used is preferably such that the ratio of the epoxy equivalent in the aqueous epoxy resin composition of the present invention to the active hydrogen equivalent in the curing agent [epoxy equivalent / active hydrogen equivalent] is in the range of 0.75 to 1.25.

[0057] The aqueous epoxy resin composition of the present invention can be used in combination with a wide variety of other synthetic resin emulsions, as needed, without particular limitation, as long as the effects of the present invention are not impaired. Specific examples include acrylic resin emulsions, acrylic / styrene copolymer resin emulsions, acrylic silicone resin emulsions, fluororesin composite acrylic resin emulsions, urethane resin emulsions, and vinyl acetate / ethylene copolymer resin emulsions. These may be self-crosslinking types or known reactive curing types that are cured by a curing agent.

[0058] The aqueous epoxy resin composition of the present invention may further contain other additives as needed, such as anti-cracking agents, anti-sagging agents, flow-extending agents, antifoaming agents, curing accelerators, ultraviolet absorbers, and light stabilizers.

[0059] The uses of the aqueous epoxy resin composition of the present invention are not particularly limited, but examples thereof include paints, adhesives, fiber sizing agents, concrete primers, etc.

[0060] When the aqueous epoxy resin composition of the present invention is used for coating applications, it is preferable to blend, as necessary, various pigments such as anti-rust pigments, coloring pigments, extender pigments, and various additives, etc. The pigment may be used in the form of a pigment dispersion paste, i.e., a dispersion prepared by pre-dispersing the pigment, a pigment dispersant, and a portion of the coating film-forming components used as needed in a small amount of aqueous medium.

[0061] The content of the various pigments is preferably 600 parts by mass or less, and more preferably 450 parts by mass or less, per 100 parts by mass of the solid content of the synthetic resin in the aqueous epoxy resin composition.

[0062] Although lead-based or chromium-based anti-rust pigments can be used, low-pollution types such as zinc phosphate, zinc molybdate, calcium molybdate, aluminum phosphomolybdate, calcium phosphate, aluminum phosphate, zinc phosphomolybdate, zinc phosphite, borate, barium metaborate, nitro compound, and tungstate are more preferred.

[0063] Examples of the color pigment include titanium oxide, red iron oxide, yellow iron oxide, carbon black, azo pigments, phthalocyanine pigments, anthraquinone pigments, quinacridone pigments, indigo pigments, dioxazine pigments, perylene pigments, isoindolinone pigments, and diketopyrrolopyrrole pigments.

[0064] Examples of the extender pigment include calcium carbonate, precipitated barium sulfate, talc, clay, diatomaceous earth, and mica.

[0065] In addition to the above components, various additives may be blended into the paint to the extent that they do not impair the effects of the present invention, for the purpose of imparting and improving functions such as storage stability, paint workability, finish, weather resistance, etc. Specific examples of such additives include dispersants, anti-sagging / anti-settling agents, color-shifting inhibitors, matting agents, thickeners, film-forming aids, antifoaming agents, preservatives, mildew inhibitors, anti-algae agents, antifreeze agents, ultraviolet absorbers, and light stabilizers.

[0066] The amount of the additives to be added is preferably in the range of 10 to 70 parts by mass per 100 parts by mass of the solid content of the aqueous epoxy resin composition.

[0067] When the aqueous epoxy resin composition of the present invention is used for coating, the coating method is not particularly limited, and can be performed by roll coating, spraying, brushing, spatula, bar coater, dip coating, or electrodeposition coating. Post-treatment methods after coating can include room temperature drying and heat curing. The heating temperature for heat curing is preferably in the range of 50 to 250°C, and more preferably in the range of 60 to 230°C. The heating time is preferably in the range of 2 to 30 minutes, and more preferably in the range of 5 to 20 minutes.

[0068] The aqueous epoxy resin composition of the present invention is used for general purposes such as aqueous coating materials for architectural interiors, aqueous coating materials for architectural exteriors and inorganic building materials, aqueous coating materials for rust prevention of iron parts, aqueous coating materials for automobile repair, and industrial purposes such as automobile coating materials, beverage cans, etc. Among these, because of its excellent corrosion prevention properties and dryness to the touch, it is suitably used as aqueous coating materials for rust prevention of iron parts for heavy corrosion protection of steel structures, bridges, etc., particularly as an aqueous coating material for rust prevention of iron parts as an undercoat.

[0069] Furthermore, when the aqueous epoxy resin composition of the present invention is used as an adhesive, there are no particular limitations, and it can be applied to substrates by spraying, brushing, or spatula, and then the bonding surfaces of the substrates are brought together, and a strong adhesive layer can be formed at the joint by fixing or pressing the periphery. Suitable substrates include steel plates, concrete, mortar, wood, resin sheets, and resin films, and it is more preferable to apply the composition to the substrates after various surface treatments, such as physical treatments such as polishing, electrical treatments such as corona treatment, and chemical treatments such as chemical conversion treatment, as necessary.

[0070] Furthermore, when the aqueous epoxy resin composition of the present invention is used as a fiber sizing agent, it can be used in any manner, including, for example, applying the composition to fibers immediately after spinning using a roller coater, winding the resulting fiber strand, and then drying. The fibers used are not particularly limited, and examples include inorganic fibers such as glass fiber, ceramic fiber, asbestos fiber, carbon fiber, and stainless steel fiber; natural fibers such as cotton and hemp; and synthetic fibers such as polyester, polyamide, and urethane. The substrate may take the form of short fiber, long fiber, yarn, mat, sheet, or the like. The amount used as a fiber sizing agent is preferably 0.1 to 2 mass% in terms of resin solids relative to the fiber. [Example]

[0071] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the examples given below.

[0072] (Synthesis Example 1: Synthesis of aqueous resin (1)) A glass flask equipped with a thermometer, stirrer, condenser, pressure reducer, and temperature controller was charged with 1,000 parts by weight of polyethylene glycol (PEG-2000 manufactured by Jiangsu Haian Petrochemical Co., Ltd., number-average molecular weight Mn = 2,000). The temperature was raised to 110°C and the flask was dehydrated under reduced pressure for 1 hour. After returning the pressure to normal with nitrogen, 154 parts by weight of hexahydrophthalic anhydride (RIKACID HH manufactured by New Japan Chemical Co., Ltd.) was added and the mixture was reacted at 130°C for 5 hours under a nitrogen atmosphere. 340 parts by weight of BPF-type epoxy resin (EPICLON 830-S manufactured by DIC Corporation, epoxy equivalent 170 g / eq.) and 1 part by weight of triphenylphosphine (manufactured by Hokko Chemical Co., Ltd.) were then added and reacted at the same temperature for 5 hours to obtain aqueous resin (1), which was solid at room temperature. The epoxy equivalent of this aqueous resin (1) was 1,550 g / eq. It was also confirmed that this aqueous resin (1) could be diluted with water.

[0073] (Synthesis Example 2: Synthesis of aqueous resin (2)) Aqueous resin (2) that was solid at room temperature was obtained in the same manner as in Synthesis Example 1, except that the BPF-type epoxy resin used in Synthesis Example 1 was changed to 376 parts by mass of a BPA-type epoxy resin (EPICLON 850-S manufactured by DIC Corporation, epoxy equivalent: 188 g / eq.). The epoxy equivalent of this aqueous resin (2) was 1,600 g / eq. and it could be diluted with water.

[0074] (Synthesis Example 3: Synthesis of aqueous resin (3)) An aqueous resin (3) that was solid at room temperature was obtained in the same manner as in Synthesis Example 1, except that the polyethylene glycol (PEG-2000 manufactured by Jiangsu Haian Petrochemical Co., Ltd.) used in Synthesis Example 1 was changed to 2,000 parts by mass of polyethylene glycol (PEG-4000 manufactured by Jiangsu Haian Petrochemical Co., Ltd., number average molecular weight Mn = 4,000). The epoxy equivalent of this aqueous resin (3) was 2,550 g / eq. and could be diluted with water.

[0075] (Synthesis Example 4: Synthesis of aqueous resin (4)) An aqueous resin (4) that was solid at room temperature was obtained in the same manner as in Synthesis Example 1, except that the polyethylene glycol (PEG-2000 manufactured by Jiangsu Haian Petrochemical Co., Ltd.) used in Synthesis Example 1 was changed to 3,000 parts by mass of polyethylene glycol (PEG-6000 manufactured by Jiangsu Haian Petrochemical Co., Ltd., number average molecular weight Mn = 6,000). The epoxy equivalent of this aqueous resin (4) was 3,540 g / eq. and it was dilutable with water.

[0076] (Comparative Synthesis Example 1: Synthesis of Water-Based Resin (5)) An aqueous resin (5) that was solid at room temperature was obtained in the same manner as in Synthesis Example 1, except that the polyethylene glycol (PEG-2000 manufactured by Jiangsu Haian Petrochemical Co., Ltd.) used in Synthesis Example 1 was changed to 5,000 parts by mass of polyethylene glycol (PEG-10000 manufactured by Jiangsu Haian Petrochemical Co., Ltd., number average molecular weight Mn = 10,000). The epoxy equivalent of this aqueous resin (5) was 5,600 g / eq.

[0077] (Comparative Synthesis Example 2: Synthesis of Water-Based Resin (6)) A glass flask equipped with a thermometer, stirrer, condenser, pressure reducer, and temperature controller was charged with 2,000 parts by weight of polyethylene glycol (PEG-4000, manufactured by Jiangsu Haian Petrochemical Co., Ltd.). The temperature was raised to 110°C and the mixture was dehydrated under reduced pressure for 1 hour. After returning the pressure to normal with nitrogen, 376 parts by weight of BPA-type epoxy resin (EPICLON 850-S, manufactured by DIC Corporation) and 1 part by weight of boron trifluoride ethyl ether complex (reagent: SIGMA-Aldrich) were added and reacted at 130°C for 5 hours under a nitrogen atmosphere to obtain aqueous resin (6), which was solid at room temperature. The epoxy equivalent of this aqueous resin (6) was 2,500 g / eq.

[0078] (Comparative Synthesis Example 3: Synthesis of Water-Based Resin (7)) A glass flask equipped with a thermometer, stirrer, condenser, pressure reducer, and temperature controller was charged with 400 parts by weight of polyethylene glycol (PEG-800 manufactured by Jiangsu Haian Petrochemical Co., Ltd., number-average molecular weight Mn = 800). The temperature was raised to 110°C and dehydrated under reduced pressure for 1 hour. After returning the pressure to normal with nitrogen, 164 parts by weight of methyl-tetrahydrophthalic anhydride (HN-2000 manufactured by Resonac) was added and reacted for 5 hours at 130°C under a nitrogen atmosphere. Furthermore, 340 parts by weight of BPF-type epoxy resin (EPICLON 830-S manufactured by DIC Corporation) and 1 part by weight of triphenylphosphine (manufactured by Hokko Chemical Co., Ltd.) were added and reacted for 5 hours to obtain aqueous resin (7), which was solid at room temperature. The epoxy equivalent of this aqueous resin (7) was 1,550 g / eq.

[0079] (Example 1: Preparation of aqueous epoxy resin composition (1)) A glass flask equipped with a thermometer, stirrer, condenser, pressure reducer, and temperature controller was charged with 60 parts by weight of the aqueous resin (1) obtained in Synthesis Example 1, 1,067 parts by weight of a BPA-type epoxy resin ("EPICLON 1051-75M" manufactured by DIC Corporation, solid epoxy equivalent weight 475 g / eq., 75% nonvolatile content methyl ethyl ketone MEK solution), and 200 parts by weight of a rubber-modified epoxy resin ("TSR-960" manufactured by DIC Corporation, solid epoxy equivalent weight 240 g / eq.). The mixture was stirred uniformly at 70°C for 1 hour, then cooled to 40-50°C, the stirring speed was increased to 4,000 rpm, and 850 parts by weight of ion-exchanged water was added dropwise over 3 hours. The solids concentration was then adjusted by partially distilling off the methyl ethyl ketone-based medium under reduced pressure, yielding an aqueous epoxy resin composition (1) with a nonvolatile content of 60%. The B-type viscosity of this aqueous epoxy resin composition (1) was 3100 mPa s, and the d50 particle size was 0.42 μm. The B-type viscosity was measured using a TVB-10 manufactured by Toki Co., Ltd., and the value was read 3 minutes after the start of measurement. The d50 particle size was measured using a UPA-150 manufactured by Microtrac Bell.

[0080] (Examples 2 to 9: Preparation of aqueous epoxy resin compositions (2) to (9)) Using the formulations shown in Table 1, aqueous epoxy resin compositions (2) to (9) were obtained in the same manner as in Example 1.

[0081] (Comparative Examples 1 to 6: Preparation of Waterborne Epoxy Resin Compositions (R1) to (R6)) Using the formulations shown in Table 2, the aqueous epoxy resin compositions (R1) to (R6) were obtained in the same manner as in Example 1.

[0082] [Method for evaluating storage stability of aqueous epoxy resin composition] Approximately 90 g of each aqueous epoxy resin composition obtained in the Examples and Comparative Examples was weighed out and placed in a 100 ml glass bottle, and stored at room temperature (25°C). After a predetermined period of time (after 3 months and after 6 months), the appearance was visually observed and evaluated according to the following evaluation criteria.

[0083] A: No separation or sedimentation B: Separation in the upper layer C: Clear separation and sedimentation

[0084] [Table 1]

[0085] [Table 2]

[0086] HP-7200: DIC Corporation EPICLON HP-7200, dicyclopentadiene-type epoxy resin, epoxy equivalent weight 265g / eq. N-770: DIC Corporation EPICLON N-770, phenolic novolac epoxy resin, epoxy equivalent 190g / eq. F108: ADEKA Corporation surfactant F108, ethylene oxide-propylene oxide copolymer

[0087] (Examples 10 to 18: Preparation of paints (1) to (9)) Paints (1) to (9) were prepared according to the blending ratios shown in Table 3.

[0088] (Comparative Examples 7 to 11: Preparation of Paints (R1) to (R5)) Paints (R1) to (R5) were prepared according to the blending ratios shown in Table 4. The aqueous epoxy resin composition (R4) was not stable enough to be made into a paint.

[0089] Table 3 shows the compositions of the paints (1) to (9) and (R1) to (R5) prepared in the examples and comparative examples.

[0090] [Table 3]

[0091] D755W: BASF pigment dispersant BYK-346: BYK Wetting Agent BYK-024: BYK Defoamer DPnB: Dipropylene glycol-normal butyl ether (DOW) BYK-425: Viscosity modifier manufactured by BYK Co., Ltd. X-150: HALOX rust spot inhibitor R-110-7: Titanium Industry Iron Oxide SPZ-391: HALOX anti-rust pigment B-35: Barium sulfate manufactured by Sakai Chemical Industry Co., Ltd.

[0092] [Table 4]

[0093] <Coating film evaluation> The paints (1) to (9) and (R1) to (R5) obtained in the examples and comparative examples were spray-coated onto cold-rolled steel plates ("SPCC-SB" manufactured by TP Giken, the surface of which was degreased with xylene and then water-polished with sandpaper #240) to form coatings with a dry thickness of approximately 60 μm. After curing at 25°C for one week, various tests were carried out under the following conditions. Similarly, various tests were carried out using aluminum: A5052P and Mg alloy: AZ091D as the substrate.

[0094] [Method for measuring grid adhesion] The adhesion was measured by a method conforming to GB / T 9286-1998.

[0095] [Method for measuring pencil hardness] The pencil hardness was measured according to the method in accordance with GB / T 6739-2006.

[0096] [Method for measuring impact strength] The impact strength was measured by a method in accordance with GB / T 1732-1993.

[0097] [Water resistance evaluation method] Water resistance was evaluated by checking for changes in the coating color and the occurrence of bubbles or rust using a method in accordance with GB / T 1733-1993. The absence of color changes, bubbles or rust indicates good corrosion resistance.

[0098] [Salt spray resistance SST evaluation method] Using a method conforming to ASTM B117, salt spray resistance was measured by checking for the presence of bubbles on the coating surface after 500 hours of testing and measuring the width of peeling from the cut area. Note that the absence of bubbles and the smaller the peeling width, the better the corrosion resistance.

[0099] [Table 5]

[0100] [Table 6]

Claims

1. As essential reaction raw materials, an epoxy resin (a1), a polybasic acid anhydride (a2), and a polyalkylene glycol (a3) ​​having a number average molecular weight of 1,000 to 6,000 are mixed, an aqueous resin (A) used in a mass ratio represented by [(a2) + (a3)] / (a1) in the range of 2 to 12; an epoxy resin (B) containing a bisphenol A type epoxy resin; An aqueous medium (C), an aqueous epoxy resin composition in which the mass ratio of the aqueous resin (A) to the epoxy resin (B) [(B) / (A)] is in the range of 10 to 30;

2. 2. The aqueous epoxy resin composition according to claim 1, wherein the epoxy resin (a1) comprises a bisphenol F type epoxy resin.

3. 2. The aqueous epoxy resin composition according to claim 1, wherein the polybasic acid anhydride (a2) comprises hexahydrophthalic anhydride.

4. 2. The aqueous epoxy resin composition according to claim 1, wherein the epoxy equivalent of the aqueous resin (A) is 1,000 to 5,000 g / eq.

5. 2. The aqueous epoxy resin composition according to claim 1, wherein the epoxy resin (B) further contains at least one selected from the group consisting of rubber-modified epoxy resins, dicyclopentadiene-type epoxy resins, and phenol novolac-type epoxy resins.

6. 2. The aqueous epoxy resin composition according to claim 1, wherein the epoxy resin (B) contains the bisphenol A type epoxy resin in an amount of 40 mass % or more.

7. A coating material comprising the aqueous epoxy resin composition according to any one of claims 1 to 6 and a curing agent.

8. An article having a cured coating film of the coating material according to claim 7.

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