Water-based anticorrosion paint composition

Abstract

To provide a water-based anticorrosive coating composition that can form an anticorrosive coating layer having excellent anticorrosive performance and achieving both FR inhibition and initial water resistance.SOLUTION: A water-based anticorrosive coating composition contains an epoxy resin (A), an amine compound (B), a flash rust inhibitor (C), and a polyfunctional methacrylate (D).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a water-based anticorrosion coating composition, an anticorrosion coating, a substrate with an anticorrosion coating, and a method for producing a substrate with an anticorrosion coating. [Background technology]

[0002] BACKGROUND ART For the purpose of long-term protection of substrates such as steel structures, the substrates are coated with anticorrosive coating compositions such as epoxy resin-based anticorrosive coating compositions. In recent years, with the strengthening of regulations on organic solvent emissions aimed at taking into consideration the natural environment, the painting work environment, etc., progress has been made in reducing the VOC (volatile organic compound) content of solvent-based anticorrosion coating compositions. One method for reducing VOC content is to use water-based paints.

[0003] Because water-based anticorrosion coating compositions contain water, they are prone to a phenomenon known as flash rust (hereinafter also referred to as "FR"), which occurs when rust forms after the coating is applied and before the coating dries and forms a film. In order to suppress the occurrence of such FR, an FR inhibitor is often blended into water-based anticorrosive coating compositions, and for example, a water-based coating composition described in Patent Document 1 is disclosed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-122114 Summary of the Invention [Problem to be solved by the invention]

[0005] It has been found that, although the incorporation of an FR inhibitor into a water-based anticorrosion coating composition can suppress the occurrence of FR, it can also reduce the initial water resistance (water resistance before complete curing) due to a decrease in low-temperature curing ability. Specifically, it has been found that after a water-based anticorrosion coating composition containing an FR inhibitor is applied to a substrate outdoors in winter, if the coated substrate comes into contact with water due to rainfall or other reasons, blisters and cracks occur in the anticorrosion coating film. In other words, conventional water-based anticorrosive coating compositions have been unable to simultaneously achieve both suppression of FR generation and initial water resistance, and there is room for improvement in achieving both.

[0006] Furthermore, it was found that the thicker the anticorrosion coating film formed (e.g., 80 μm or more) in order to further suppress the occurrence of FR, the poorer the initial water resistance tends to be. Furthermore, it was found that FR is particularly likely to occur in substrates with welded joints.

[0007] The present invention has been made in view of the above, and an object of the present invention is to provide a water-based anticorrosive coating composition that is capable of forming an anticorrosive coating film that has excellent corrosion prevention properties and that satisfies both FR suppression and initial water resistance. [Means for solving the problem]

[0008] As a result of extensive research into methods for solving the above problems, the present inventors have found that the above problems can be solved by the following configuration examples, and have thus completed the present invention. An example of the configuration of the present invention is as follows.

[0009] <1> A water-based anticorrosion coating composition comprising an epoxy resin (A), an amine compound (B), a flash rust inhibitor (C), and a polyfunctional (meth)acrylate (D).

[0010] <2> a first agent containing the epoxy resin (A) and a polyfunctional (meth)acrylate (D); a second agent containing the amine compound (B) and the flash rust inhibitor (C); Including, <1> The water-based anticorrosion coating composition according to claim 1.

[0011] <3> The polyfunctional (meth)acrylate (D) is a tri- or higher functional (meth)acrylate compound. <1> or <2> The water-based anticorrosion coating composition according to claim 1.

[0012] <4> The functional group ratio represented by the following formula (1) is 0.010 to 0.30. <1> ~ <3> 1. The aqueous anticorrosion coating composition according to any one of the preceding claims. Functional group ratio=(amount of the solid content of the polyfunctional (meth)acrylate (D) / functional group equivalent of the solid content of the polyfunctional (meth)acrylate (D)) / (amount of the solid content of the amine compound (B) / active hydrogen equivalent of the solid content of the amine compound (B)) (1)

[0013] <5> For forming anti-corrosion coatings with a dry thickness of 80 μm or more. <1> ~ <4> 1. The aqueous anticorrosion coating composition according to any one of the preceding claims.

[0014] <6> For substrates having welds, <1> ~ <5> 1. The aqueous anticorrosion coating composition according to any one of the preceding claims.

[0015] <7> <1> ~ <6> 1. A corrosion-resistant coating film formed from the aqueous corrosion-resistant coating composition according to any one of claims 1 to 9.

[0016] <8> <7> A substrate with a corrosion-resistant coating film, comprising the corrosion-resistant coating film according to claim 1 and a substrate. <9> The substrate is a substrate having a weld. <8> The substrate with the anticorrosion coating film according to claim 1.

[0017] <10> A method for producing a substrate with a corrosion-resistant coating, comprising the following steps [1] and [2]: [1] The substrate is <1> ~ <6> a step of applying the aqueous anticorrosive coating composition according to any one of [2] A step of drying the applied water-based anticorrosion coating composition to form an anticorrosion coating film. [Effects of the Invention]

[0018] According to the present invention, it is possible to form a corrosion-protective coating film that has excellent corrosion prevention properties and that satisfies both FR suppression and initial water resistance.Furthermore, according to the present invention, it is possible to form a corrosion-protective coating film that has excellent corrosion prevention properties and that satisfies both FR suppression and initial water resistance, even when a thick corrosion-protective coating film is formed or when a corrosion-protective coating film is formed on a substrate having a welded portion. DETAILED DESCRIPTION OF THE INVENTION

[0019] <Water-based anticorrosion coating composition> The aqueous anticorrosive coating composition according to the present invention (hereinafter also referred to as "the composition") contains an epoxy resin (A) [hereinafter also referred to simply as "component (A)"; the same applies to other components], an amine compound (B), a flash rust inhibitor (C), and a polyfunctional (meth)acrylate (D).

[0020] The water-based anticorrosion coating composition refers to a composition in which the water content is 50% by mass or more relative to 100% by mass of the total amount of the dispersion medium and solvent in the composition, and the water content is preferably 70 to 100% by mass, more preferably 75 to 100% by mass. The content of water in the present composition is not particularly limited, but is preferably 10 to 50% by mass, and more preferably 25 to 45% by mass.

[0021] The present composition can easily form a corrosion-resistant coating film that has excellent corrosion resistance and combines FR suppression and initial water resistance, and is therefore suitable for use on substrates that require such corrosion resistance. However, in terms of being able to more effectively utilize the effects of the present composition, the composition is more suitable for applications requiring the formation of a corrosion-resistant coating film with a dry film thickness of 80 μm or more (for forming corrosion-resistant coating films with a dry film thickness of 80 μm or more) and for protecting substrates that are prone to FR, such as substrates with welds.

[0022] The composition may be a one-component composition, but considering storage stability and ease of storage, it is preferably a multi-component composition containing a first part and a second part. Such a multi-component composition is preferably a two-component composition containing a first part containing components (A) and (D) and a second part containing components (B) and (C). The composition may also be a three- or more-component composition containing a third part other than the first and second parts. These first, second and third agents are usually stored, preserved and transported in separate containers and mixed together immediately before use. The multi-component composition is a composition obtained by mixing the first agent, the second agent, and, if necessary, a third agent, etc. In such a multi-component composition, the first agent, the second agent, the third agent, etc. can be said to be components of a kit for preparing the present composition, or in other words, the present multi-component composition can be said to be a kit for an aqueous anticorrosive coating composition containing the first agent, the second agent, and, if necessary, the third agent, etc.

[0023] <First agent> The first agent preferably contains component (A) and component (D), and is more preferably a liquid containing these, in order to facilitate the formation of a corrosion-protective coating film with better initial water resistance. The first agent containing these ingredients can be said to be the main agent.

[0024] <Epoxy resin (A)> The component (A) is not particularly limited, but is preferably a water-based epoxy resin, and preferably has two or more epoxy groups in one molecule. There are no particular restrictions on the resin properties of component (A), such as molecular weight and epoxy equivalent. The component (A) used in the present composition may be one type or two or more types.

[0025] Examples of component (A) include bisphenol A type epoxy resins, bisphenol F type epoxy resins, novolac type epoxy resins (e.g., phenol novolac type epoxy resins, cresol novolac type epoxy resins, etc.), alicyclic epoxy resins, and aliphatic modified epoxy resins.

[0026] When preparing the present composition (particularly the first agent), an emulsion or dispersion may be used as the raw material for component (A). When an emulsion or dispersion is used, the content of the epoxy resin in 100% by mass of the raw material is preferably 40 to 90% by mass, since this allows for the production of a composition that is superior in ease of preparation, storage stability, etc. The remainder of the raw materials may contain water, and may also contain conventionally known components such as surfactants, if necessary.

[0027] Commercially available products may be used as the raw material for component (A), and examples thereof include emulsions of bisphenol A epoxy resins such as Yukaresin RE-1050 (manufactured by Yoshimura Oil Chemicals Co., Ltd.), ECOBOND SEW-47S (manufactured by SNC Chemicals), and Adekaresin EM-101-50 (manufactured by Adeka Corporation), and a self-emulsifying bisphenol A epoxy resin such as Adekaresin EM-0425C (manufactured by Adeka Corporation).

[0028] The solid content of component (A) is preferably 20 to 50 mass%, more preferably 25 to 45 mass%, relative to 100 mass% of the nonvolatile content of the composition, from the viewpoint of easily forming an anticorrosion coating film that is well-balanced in terms of corrosion prevention, water resistance, and adhesion to the substrate.

[0029] The nonvolatile content of the composition refers to the mass percentage of the coating film (heating residue) after the composition has been fully cured (heated), or the coating film (heating residue) itself. The nonvolatile content can be calculated based on JIS K 5601-1-2 by weighing 1±0.2 g of the composition (e.g., the composition immediately after mixing the first and second parts) onto a flat-bottom dish, spreading it evenly using a wire of known mass, drying it at 23°C for 24 hours, and then heating it at 125°C for 1 hour (at normal pressure). The nonvolatile content is equivalent to the total solid content of the raw material components used in the composition (components other than the dispersion medium and solvent).

[0030] In the present invention, the components other than the dispersion medium and solvent (volatile components) in the first and second parts, components (A) to (D), and other components described below are referred to as "solids."

[0031] <Polyfunctional (meth)acrylate compound (D)> The component (D) is not particularly limited, and examples thereof include bifunctional (meth)acrylate compounds and trifunctional or higher functional (meth)acrylate compounds. Among these, it is preferable to use trifunctional or higher functional (meth)acrylate compounds because they have many crosslinking points, increase crosslinking density, and improve initial water resistance. The component (D) used in the present composition may be one type or two or more types.

[0032] Examples of bifunctional (meth)acrylate compounds include ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate (e.g., diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and other polyethylene glycol di(meth)acrylates), propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate (e.g., tripropylene glycol di(meth)acrylate, and other polypropylene glycol di(meth)acrylates), neopentyl glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, and neopentyl glycol dihydroxypivalate. (Meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, glycerin di(meth)acrylate, 2,2-bis[4-((meth)acryloyloxyethoxy)phenyl]propane, 2,2-bis[4-((meth)acryloyloxydiethoxy)phenyl]propane, 2,2-bis[4-((meth)acryloyloxypolyethoxy)phenyl]propane. Among these, 1,6-hexanediol di(meth)acrylate and polyethylene glycol di(meth)acrylate are preferred.

[0033] Examples of the tri- or higher functional (meth)acrylate compound include trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, diglycerin tetra(meth)acrylate, dimethylolpropane tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, tris(meth)acryloyloxyethyl phosphate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; and polyalkylene oxides (-(RO) n -[R is an alkylene group, and n is the number of repeating units, which is a value of 2 or more] modified products (e.g., polyethylene oxide (hereinafter also referred to as "PEO") modified products, polypropylene oxide modified products, polybutylene oxide modified products)). Among these, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and ethylene oxide-modified trimethylolpropane tri(meth)acrylate are preferred.

[0034] As described above, a (meth)acrylate having a polyalkylene oxide (hereinafter also referred to as "PAO") structure can also be used as component (D), but the content of the polyalkylene oxide structure derived from component (D) contained in the present composition is preferably 2.5 mass% or less relative to 100 mass% of the nonvolatile content of the present composition, and the lower limit is not particularly limited, and is 0 mass%. When the content of the PAO structure derived from component (D) contained in the present composition is within the above range, it is possible to form a corrosion-protective coating film that has excellent corrosion prevention properties and that combines FR suppression and initial water resistance without reducing the water resistance of the coating film. The content of the PAO structure derived from component (D) contained in the present composition is calculated from the content of the PAO structure contained in component (D) used as a raw material when preparing the present composition and the blending ratio of component (D) blended in the present composition.

[0035] The solid content of component (D) is preferably 0.005 to 5.0 mass%, more preferably 0.01 to 4.5 mass%, and even more preferably 0.05 to 3.5 mass%, relative to 100 mass% of the nonvolatile content of the composition, in order to easily form a corrosion-resistant coating film that is well-balanced in terms of FR suppression and initial water resistance.

[0036] In addition, from the viewpoint of easily forming an anticorrosion coating film that is well-balanced in terms of FR suppression and initial water resistance, the functional group ratio represented by the following formula (1) is preferably 0.010 to 0.30, more preferably 0.015 to 0.25, and even more preferably 0.020 to 0.22. Functional group ratio = (amount of solid content of component (D) / functional group equivalent of solid content of component (D)) / (amount of solid content of component (B) / (active hydrogen equivalent of solid content of component (B)) (1)

[0037] The functional group equivalent of the component (D) is also called the (meth)acrylic equivalent or the double bond equivalent, and means the mass (g) per 1 mol of functional group obtained by dividing the number of moles of functional groups ((meth)acryloyl groups) contained therein from the mass of 1 mol of the component (D).

[0038] The "functional group equivalent" of each component means the mass (g) per 1 mol of functional group obtained by dividing the mass of 1 mol of that component by the number of moles of the functional group contained therein.

[0039] <Other ingredients> In addition to component (A) and component (D), the first agent may contain, if desired, other components such as pigments (excluding component (C)), pigment dispersants, antifoaming agents, anti-sagging agents (anti-settling agents, thixotropic agents, rheology control agents), film-forming aids, adhesion enhancers (e.g., silane coupling agents), plasticizers, water, organic solvents, etc., within the scope of the invention. These other components may each be used alone or in combination of two or more.

[0040] [Pigment] The present composition and the first agent may contain a pigment, and preferably contain a pigment. Examples of the pigment include extender pigments, color pigments, and anti-rust pigments, and may be either organic or inorganic.

[0041] Examples of the extender pigment include talc, mica, (precipitated) barium sulfate, (potassium) feldspar, kaolin, alumina white, bentonite, wollastonite, clay, glass flakes, aluminum flakes, magnesium carbonate, barium carbonate, calcium carbonate, dolomite, and silica, with talc, mica, silica, (precipitated) barium sulfate, and (potassium) feldspar being particularly preferred.

[0042] When the present composition contains a body pigment, the content of the body pigment is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, relative to 100% by mass of the nonvolatile content of the present composition.

[0043] Examples of the color pigment include inorganic pigments such as carbon black, titanium dioxide (titanium white), iron oxide (red iron oxide), yellow iron oxide, scaly iron oxide, and ultramarine, and organic pigments such as cyanine blue and cyanine green. Titanium white, carbon black, and red iron oxide are particularly preferred.

[0044] When the present composition contains a color pigment, the content of the color pigment is preferably 0.01 to 50% by mass, and more preferably 0.1 to 40% by mass, relative to 100% by mass of the nonvolatile content of the present composition.

[0045] Examples of the rust-preventive pigment include zinc phosphate compounds, calcium phosphate compounds, aluminum phosphate compounds, magnesium phosphate compounds, zinc phosphite compounds, calcium phosphite compounds, aluminum phosphite compounds, strontium phosphite compounds, aluminum tripolyphosphate compounds, molybdate compounds, zinc cyanamide compounds, borate compounds, nitro compounds, and composite oxides.

[0046] When the present composition contains an anti-rust pigment, the content of the anti-rust pigment is preferably 1 to 20 mass %, more preferably 3 to 15 mass %, relative to 100 mass % of the non-volatile content of the present composition.

[0047] When the present composition contains a pigment, the pigment volume concentration (PVC) in the present composition is preferably 1 to 40%, more preferably 10 to 35%, and even more preferably 20 to 35%, from the viewpoints that a present composition having excellent coating workability can be easily obtained, and an anticorrosion coating film having excellent adhesion to the substrate and excellent corrosion resistance due to stress relaxation can be easily formed.

[0048] The PVC refers to the total volume concentration of pigments relative to the volume of nonvolatile matter in the composition, and can be calculated specifically by the following formula (2): PVC [%] = total volume of all pigments in the composition × 100 / volume of nonvolatile matter in the composition (2)

[0049] The volume of the nonvolatile content of the composition can be calculated from the mass and true density of the nonvolatile content of the composition. The mass and true density of the nonvolatile content may be measured values ​​or values ​​calculated from the raw materials used. The volume of the pigment can be calculated from the mass and true density of the pigment used. The mass and true density of the pigment may be measured values ​​or values ​​calculated from the raw materials used. For example, the volume can be calculated by separating the pigment from other components from the nonvolatile content of the composition and measuring the mass and true density of the separated pigment.

[0050] [Pigment dispersant] Examples of the pigment dispersant include various known organic or inorganic pigment dispersants, such as aliphatic amines or organic acids (e.g., "Disperbyk-2055" (manufactured by BYK Japan KK), "Disperbyk-101" (manufactured by BYK Japan KK), "BYK-190" (manufactured by BYK Japan KK), and "ANTI-TERRA-250" (manufactured by BYK Japan KK)).

[0051] When the present composition contains a pigment dispersant, the solid content of the pigment dispersant is preferably 0.5 to 10 mass %, more preferably 1 to 6 mass %, relative to 100 mass % of the nonvolatile content of the present composition, from the viewpoint that a composition excellent in the effects of reducing paint viscosity and preventing color separation can be easily obtained.

[0052] [Antifoaming agent] The present composition preferably contains an antifoaming agent, since this can suppress the generation of bubbles during the production or application of the composition, or can break up bubbles that have generated in the composition, thereby making it possible to easily form a corrosion-protective coating film having the desired physical properties. The defoaming agent may be a commercially available product, and examples of such commercially available products include "BYK-392," "BYK-066N," and "BYK-1790" (all manufactured by BYK Japan K.K.), "TEGO Airex 902W" (manufactured by EVONIK Industries), "SURFYNOL SE-F" (manufactured by EVONIK Industries), and "Spectrasyn 40" (manufactured by Exxonmobil Chemical Company).

[0053] When the present composition contains an antifoaming agent, the content of the solids of the antifoaming agent is preferably 0.05 to 5.0 mass%, more preferably 0.1 to 2.0 mass%, relative to 100 mass% of the nonvolatile content of the present composition, from the viewpoints of being able to sufficiently suppress the generation of foam and easily form a corrosion-protective coating film with the desired physical properties.

[0054] [Anti-sagging agent] The anti-sagging agent is not particularly limited, but is preferably a material that can suppress sedimentation of pigments and the like in the present composition and improve its storage stability, or a material that can improve the anti-sagging properties of the present composition during or after application. Examples of the anti-sagging agent that can be used include conventionally known anti-sagging agents such as stearate salts of Al, Ca, and Zn, lecithin salts, organic clay waxes such as alkylsulfonates, polyethylene wax, amide wax, hydrogenated castor oil wax, mixtures of hydrogenated castor oil wax and amide wax, synthetic finely powdered silica, oxidized polyethylene wax, mineral clay viscosity modifiers, urethane association viscosity modifiers, acrylic acid viscosity modifiers, and cellulose viscosity modifiers. Of these, amide wax and mineral clay viscosity modifiers are preferred.

[0055] Such anti-sagging agents may be commercially available products, such as "Disparlon HQ-800" manufactured by Kusumoto Chemical Co., Ltd., "RHEOBYK 420" manufactured by BYK Japan K.K., "Chikudol W-502" manufactured by Kyoeisha Chemical Co., Ltd., "BENTONE LT" and "BENTONE DE" manufactured by Elementis Specialties, Inc., and "Aerosil R972" manufactured by Nippon Aerosil Co., Ltd.

[0056] When the present composition contains an anti-sagging agent, the content of the solid content of the anti-sagging agent is preferably 0.1 to 10% by mass relative to 100% by mass of the nonvolatile content of the present composition.

[0057] [Film-forming agent] Since the present composition contains water, which may cause the composition to freeze in winter, and also from the viewpoint of improving film-forming properties at low temperatures and the finished appearance of the resulting coating film, it is preferable that the composition contain a film-forming aid.

[0058] The film-forming aid may be an organic compound having a boiling point of 180°C or higher under normal pressure, which is typically used in aqueous coating compositions. Examples include linear or branched aliphatic alcohols having 5 to 15 carbon atoms; alcohols having an aromatic ring, such as benzyl alcohol; monoethers, such as (poly)ethylene glycol or (poly)propylene glycol; (poly)ethylene glycol ether esters; and (poly)propylene glycol ether esters.

[0059] When the present composition contains a film-forming aid, the content thereof is preferably 0.5 to 20 mass %, more preferably 2 to 15 mass %, relative to 100 mass % of the nonvolatile content of the present composition, from the viewpoint of being able to easily form a corrosion-protective coating film that has excellent film-forming properties and appearance at low temperatures.

[0060] [water] The raw materials such as component (A) used in preparing the present composition (particularly the first agent) may contain water, but it is preferable to further blend water into the present composition or the first agent in order to make the preparation of the present composition or the first agent easier and to improve the storage stability of the composition or the first agent. The water to be mixed is not particularly limited, and tap water or the like may be used, but ion-exchanged water, deionized water, or the like is preferably used.

[0061] The water content in the first agent (including water that may be contained in raw materials such as component (A) used when preparing the first agent) is not particularly limited, but is preferably 0 to 65% by mass, and more preferably 20 to 55% by mass. Furthermore, the content of water in the first agent is preferably 50% by mass or more, more preferably 70 to 100% by mass, and particularly preferably 80 to 100% by mass, relative to 100% by mass of the total amount of the dispersion medium and solvent in the first agent, in order to easily obtain the desired composition.

[0062] [Organic solvents] The organic solvent is not particularly limited as long as it has a boiling point of less than 180°C under normal pressure, and examples thereof include aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK), ether solvents such as butyl cellosolve, ester solvents such as butyl acetate, alcohol solvents such as isopropanol, isobutyl alcohol, n-butanol and methoxypropanol, aliphatic hydrocarbon solvents such as n-hexane, n-octane, 2,2,2-trimethylpentane, isooctane and n-nonane, and alicyclic hydrocarbon solvents such as cyclohexane and methylcyclohexane. The present composition may contain an organic solvent, but preferably does not contain an organic solvent.

[0063] <Second agent> The second agent preferably contains component (B) and component (C), and is more preferably a liquid containing these, in order to facilitate the formation of a corrosion-protective coating film with better FR suppression properties. The second agent containing these components can also be considered a curing agent.

[0064] <Amine Compound (B)> The component (B) is not particularly limited, and any known amine compound that has been used as a curing agent for epoxy compounds or the like can be used. The component (B) used in the present composition may be one type or two or more types.

[0065] Component (B) is not particularly limited as long as it is an amine compound other than a tertiary amine (an amine compound having only a tertiary amino group) and the flash rust inhibitor (C) described below, but an amine compound containing two or more amino groups in one molecule is preferred, and aliphatic, alicyclic, aromatic, or other amine compounds are preferred.

[0066] Examples of the aliphatic amine compounds include alkylene polyamines, polyalkylene polyamines, and alkylamino alkyl amines.

[0067] Examples of the alkylene polyamine include those represented by the formula: "H2N-R 1 -NH2" (R 1 is a divalent hydrocarbon group having 1 to 12 carbon atoms. Specific examples include methylenediamine, ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, and trimethylhexamethylenediamine.

[0068] Examples of the polyalkylene polyamine include those of the formula: "HN-(C m H 2m NH) n Specific examples include compounds represented by the formula (III) (H) (where m is an integer of 1 to 10, and n is an integer of 2 to 10, preferably an integer of 2 to 6), such as diethylenetriamine, dipropylenetriamine, triethylenetetramine, tripropylenetetramine, tetraethylenepentamine, tetrapropylenepentamine, pentaethylenehexamine, nonaethylenedecamine, bis(hexamethylene)triamine, and triethylene-bis(trimethylene)hexamine.

[0069] Examples of the alkylaminoalkylamine include those represented by the formula: 2 2N-(CH2) p -NH2" (R 2 are independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms (provided that at least one R 2 is an alkyl group having 1 to 8 carbon atoms, and p is an integer of 1 to 6. Specific examples include dimethylaminoethylamine, diethylaminoethylamine, dibutylaminoethylamine, dimethylaminopropylamine, diethylaminopropylamine, dipropylaminopropylamine, dibutylaminopropylamine, and dimethylaminobutylamine.

[0070] Other aliphatic amine compounds include, for example, tetra(aminomethyl)methane, tetrakis(2-aminoethylaminomethyl)methane, 1,3-bis(2'-aminoethylamino)propane, tris(2-aminoethyl)amine, bis(cyanoethyl)diethylenetriamine, polyoxyalkylenepolyamines (particularly, diethylene glycol bis(3-aminopropyl)ether), bis(aminomethyl)cyclohexane, isophoronediamine (IPDA), menthenediamine (MDA), o-xylylenediamine, m-xylylenediamine (MXDA), p-xylylenediamine, bis(aminomethyl)naphthalene, bis(aminoethyl)naphthalene, 1,4-bis(3-aminopropyl)piperazine, 1-(2'-aminoethylpiperazine), and 1-[2'-(2''-aminoethylamino)ethyl]piperazine.

[0071] Specific examples of the alicyclic amine compound include cyclohexanediamine, diaminodicyclohexylmethane (particularly, 4,4'-methylenebiscyclohexylamine), 4,4'-isopropylidenebiscyclohexylamine, norbornanediamine, and 2,4-di(4-aminocyclohexylmethyl)aniline.

[0072] Examples of the aromatic amine compounds include aromatic polyamine compounds having two or more primary amino groups bonded to an aromatic ring such as a benzene ring or a naphthalene ring. Specific examples of the aromatic amine compound include phenylenediamine, naphthalenediamine, diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, diaminodiethylphenylmethane, 2,4'-diaminobiphenyl, 2,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, and diethylmethylbenzenediamine.

[0073] Further examples of component (B) include modified products of the above-mentioned amine compounds, such as fatty acid modified products such as polyamidoamines, amine adducts with epoxy compounds, Mannich modified products (e.g., Mannich modified amines having a phenol-derived skeleton (phenalkamine, phenalkamide, etc.)), Michael adducts, ketimines, and aldimines. Among these, polyamidoamines, amine adducts with epoxy compounds, and Mannich modified amines having a phenol-derived skeleton are preferred.

[0074] When preparing this composition (particularly the second agent), either a water-dilutable amine compound or a non-aqueous amine compound may be used as the raw material for component (B). However, it is preferable to use a water-dilutable amine compound, as this allows for the easy formation of an anticorrosion coating film that is excellent in anticorrosion properties and drying properties.

[0075] Specific examples of raw materials for amine compounds corresponding to water-dilutable amine compounds include water-soluble amine compounds, aqueous solutions of amine compounds, aqueous dispersions of amine compounds (e.g., amine emulsions), and self-emulsifying amine compounds. Among these, it is preferable to use water-soluble amine compounds because they are easy to handle and make it easy to prepare the present composition (particularly the second agent).

[0076] The water-soluble amine compound may be the above-mentioned amine compound or a compound obtained by making the above-mentioned amine compound hydrophilic by a known method. Examples of the hydrophilization method include the introduction of a group that promotes water solubility, such as a carboxy group, a sulfonic acid group, a sulfinic acid group, a phosphonic acid group, or a hydroxyl group, or the introduction of a hydrophilic group, such as by adduct-modifying a glycidyl ether of a polyalkylene glycol. The water-soluble amine compound refers to a compound that is transparent in appearance when 30% by mass of water and 70% by mass of the amine compound are mixed at 25°C and thoroughly stirred.

[0077] Commercially available water-soluble amine compounds can be used, such as "Daitoclar I-6020" (manufactured by Daito Sangyo Co., Ltd.), "Cardolite NX8101" (manufactured by Cardolite Corporation), "KCA-7700" (manufactured by Kumho P&B Chemicals), "BECKOPOX EH 613w / 80WA" (manufactured by Allnex), and "Sunmide WH-900" (manufactured by Evonik Industries).

[0078] Specific examples of the amine emulsion include hydrophilic amines obtained by reacting the amine compounds with glycidyl ethers of polyalkylene glycols, polyoxyalkylene amines, epoxy compounds, etc.; amines having an amide structure obtained by using fatty acids and the amine compounds; and amines that have been given emulsifying ability by neutralizing the amine compounds with acids or mixing them with emulsifiers, and then (forcibly) dispersing the amines in water.

[0079] The amine emulsion may be, for example, an emulsion in which an amine compound is dispersed in an aqueous medium such as water. The emulsion is in a state where the laser light does not pass through when the emulsion is placed in a transparent glass container and irradiated with a laser pointer (model: TLP-3200, manufactured by Eiger Tools) from a position 15 cm away from the front of the container and directly facing the container. Commercially available amine emulsions can be used, such as "Fujicure FXS-918-FA" (manufactured by T&K TOKA Corporation), "EPILINK 701" (manufactured by Evonik Industries), and "Yukaresin HD-03" (manufactured by Yoshimura Oil Chemical Co., Ltd.).

[0080] The self-emulsifying amine compound is an amine compound that has the ability to emulsify when mixed with an aqueous medium described below without being mixed with an acid or an emulsifier. Specific examples include hydrophilic amines obtained by reacting the amine compound with a glycidyl ether of polyalkylene glycol, a polyoxyalkylene amine, an epoxy compound, etc., and amines having an amide structure obtained by using a fatty acid and the amine compound.

[0081] The aqueous medium is not particularly limited as long as it contains water, but the content of water in the aqueous medium is preferably 50 to 100% by mass, more preferably 60 to 100% by mass.

[0082] The aqueous medium may contain a medium other than water having a boiling point of less than 180°C under normal pressure, such as acetone, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, diacetone alcohol, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, or ethylene glycol monopropyl ether. These may be used alone or in combination.

[0083] Component (B) is preferably a water-soluble amine compound, particularly a water-soluble polyamine, from the viewpoints of being able to easily obtain a coating film that has excellent adhesion to the substrate and exhibits early water resistance, etc. Furthermore, as a raw material for component (B) when preparing the present composition (particularly the second part), a water-soluble polyamine that does not contain an emulsifier is more preferred from the viewpoints of being able to easily obtain a composition that has excellent flash rust resistance, etc.

[0084] The active hydrogen equivalent weight per solid content of the amine compound is preferably 30 to 500, more preferably 40 to 300, from the viewpoint that a coating film excellent in curability, anticorrosion properties, etc. can be easily obtained.

[0085] The solid content of component (B) is preferably 1 to 20 mass%, more preferably 2 to 10 mass%, relative to 100 mass% of the nonvolatile content of the composition, from the viewpoint of easily forming an anticorrosion coating film that is excellent in anticorrosion properties and drying properties.

[0086] Furthermore, from the viewpoint of easily forming an anticorrosion coating film that is excellent in anticorrosion properties, coating strength, and drying properties, it is desirable to use component (B) in an amount such that the reaction ratio calculated by the following formula (3) is preferably 0.3 to 1.5, more preferably 0.4 to 1.2.

[0087] Reactivity ratio={(amount of solid content of component (B) / active hydrogen equivalent of solid content of component (B))+(amount of solid content of component reactive with component (A) / functional group equivalent of solid content of component reactive with component (A))} / {(amount of solid content of component (A) / epoxy equivalent of solid content of component (A))+(amount of solid content of component reactive with component (B) / functional group equivalent of solid content of component reactive with component (B))} (3)

[0088] Here, in the formula (3), examples of the "component reactive with component (A)" include a silane coupling agent, and examples of the "component reactive with component (B)" include component (D) and a silane coupling agent. As the silane coupling agent, a silane coupling agent having an amino group or an epoxy group as a reactive group can be used. Therefore, depending on the type of the reactive group, it is necessary to determine whether the silane coupling agent is reactive with component (A) or component (B), and then calculate the reactivity ratio.

[0089] <Flash Rust Inhibitor (C)> There are no particular restrictions on the component (C), but it is preferable that the component (C) be a material that can suppress rusting caused by the elution of iron ions from the steel surface or the like during the drying process immediately after application of the composition to the surface of the active steel material, etc., and that can suppress flash rust, in which the rust or the like appears on the coating surface.

[0090] Examples of component (C) include nitrites such as sodium nitrite, potassium nitrite, calcium nitrite, strontium nitrite, barium nitrite, and ammonium nitrite; benzoates such as sodium benzoate, potassium benzoate, calcium benzoate, and ammonium benzoate; phytates such as sodium phytate and potassium phytate; organic carboxylates such as sebacic acid and dodecanoic acid; phosphoric acid derivatives such as alkyl phosphates and polyphosphoric acids; tannates; metal sulfonates; N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), and diethylenetriaminepentaacetic acid (DTPA). amine-based chelating agents such as propylenediaminetetraacetic acid (PDTA), iminodiacetic acid, nitrilotriacetic acid (NTA), diethylenetriaminepentamethylenephosphonic acid (DTPMP), and alkali metal salts thereof; addition reaction products of 4-methyl-γ-oxo-benzenebutanoic acid and N-ethylmorpholine; intercalation compounds obtained by intercalating monoalkylamines, polyamines, quaternary ammonium ions, etc. into layered phosphates such as aluminum dihydrogen tripolyphosphate; hydrazine derivatives such as hydrazide compounds, semicarbazide compounds, and hydrazone compounds; and azole compounds such as benzotriazole, its derivatives, and salts thereof.

[0091] Commercially available products may be used as component (C), and examples of such commercially available products include "Killeslite W-410" and "Killeslite W-16B" (both manufactured by Chelest Co., Ltd. / fatty acid salt-based), "SN 1305" (manufactured by Sae Kyung Industry Co., Ltd., nitrite-based), "SN 8828C" (manufactured by San Nopco Ltd., organic carboxylate-based), "SF Inhibitor 6843" (manufactured by Bernd Schwegmann GmbH, benzoate-based), "ASCOTORAN L" (manufactured by ASCOTEC GmbH, azole-based), and "HALOX FLASH-X 150" (manufactured by ICL Advanced Additives-Hammond / nitrite, benzoate-based).

[0092] The solid content of component (C) is preferably 0.1 to 5.0 mass%, more preferably 0.2 to 3.5 mass%, relative to 100 mass% of the nonvolatile content of the composition, from the viewpoint of being able to easily form a corrosion-protective coating film that combines FR suppression and initial water resistance.

[0093] <Other ingredients> In addition to component (B) and component (C), the second agent may contain, if desired, other components such as a pigment, a pigment dispersant, an antifoaming agent, an anti-sagging agent (anti-settling agent, thixotropic agent, rheology control agent), a film-forming aid, an adhesion enhancer (e.g., silane coupling agent), a plasticizer, a curing accelerator, a curing catalyst, water, an organic solvent, etc., within the scope of the invention. These other components may each be used alone or in combination of two or more. The other components may be conventionally known components, and examples of the pigment, pigment dispersant, defoamer, anti-sagging agent, film-forming aid, and organic solvent include the same components as those listed in the first agent section.

[0094] [water] The raw materials such as component (B) used in preparing the present composition (particularly the second agent) may contain water, but it is preferable to further blend water into the present composition or the second agent in order to make the preparation of the present composition or the second agent easier and to improve the storage stability of the composition or the second agent. The water to be mixed is not particularly limited, and tap water or the like may be used, but ion-exchanged water, deionized water, or the like is preferably used.

[0095] The water content in the second agent (including water that may be contained in raw materials such as component (B) used when preparing the second agent) is not particularly limited, but is preferably 5 to 70 mass %, more preferably 10 to 60 mass %. Furthermore, the content of water in the second agent is preferably 50% by mass or more, more preferably 70 to 100% by mass, and particularly preferably 80 to 100% by mass, relative to 100% by mass of the total amount of the dispersion medium and solvent in the second agent, in order to facilitate the production of the desired composition.

[0096] <Third agent> In addition to components (A) to (D), the third agent may contain other components such as pigments (e.g., zinc powder, zinc alloy powder), pigment dispersants, antifoaming agents, anti-sagging agents (anti-settling agents, thixotropic agents, rheology control agents), film-forming aids, adhesion enhancers (e.g., silane coupling agents), plasticizers, curing accelerators, curing catalysts, water, and organic solvents, provided that the effects of the present invention are not impaired. These other components may each be used alone or in combination of two or more. The other components may be conventionally known components, and examples of the pigment, pigment dispersant, defoamer, anti-sagging agent, film-forming aid, and organic solvent include the same components as those listed in the first agent section.

[0097] When the present composition is used as a zinc primer, it is preferable to contain zinc powder and / or zinc alloy powder as the third agent.

[0098] When the present composition contains zinc powder and / or zinc alloy powder, the total content of the zinc powder and zinc alloy powder is preferably 60 to 85 mass%, more preferably 70 to 80 mass%, relative to 100 mass% of the nonvolatile content of the present composition.

[0099] <Method for preparing the present composition> The present composition, the first agent, and the second agent can be prepared by mixing (kneading) the components to be blended therein. During this mixing (kneading), the components may be added and mixed all at once, or may be added and mixed in multiple batches. The present multi-component composition can be prepared by mixing (kneading) the first agent, the second agent, and an optional third agent, etc. The mixing (kneading) can be carried out using a conventionally known device such as a mixer, disperser, or stirrer, and examples of such devices include a disperser, a mixing / dispersing mill, a mortar mixer, a roll, a paint shaker, and a homogenizer. The mixing (kneading) may be carried out while heating or cooling depending on the season, environment, etc.

[0100] <Anti-corrosion coating, substrate with anti-corrosion coating> The anticorrosion coating film of the present invention (hereinafter also referred to as "the present coating film") is formed using the present composition, and the substrate with the anticorrosion coating film of the present invention (hereinafter also referred to as "the substrate with the present coating film") is a laminate having the present coating film and a substrate.

[0101] The material of the substrate is not particularly limited, and examples thereof include steel (iron, steel, ferroalloy, carbon steel, mild steel, alloy steel, etc.), non-ferrous metals (zinc, aluminum, copper, brass, zinc plating, zinc thermal spraying, etc.), and stainless steel (SUS304, SUS410, etc.). Furthermore, when mild steel (SS400, etc.) is used as the substrate, it is desirable to adjust the surface of the substrate (e.g., adjust the arithmetic mean roughness (Ra) to about 30 to 75 μm) by polishing the surface of the substrate by grit blasting, etc., as necessary. The substrate may be a substrate that has been subjected to pretreatment such as cleaning or blasting to remove rust, dirt, paint (old paint film), and the like adhering to the substrate.

[0102] The substrate is not particularly limited, and can be used without limitation on substrates that require corrosion resistance. However, in terms of the effects of using the present composition being more pronounced, preferred examples include (steel) structures such as ships, marine structures, plants, bridges, tanks, and containers. Furthermore, the substrate is preferably a substrate having a welded portion, in order to further exert the effects of the present invention, etc. Although FR is likely to occur in such substrates having welded portions, by using the present composition, FR can be sufficiently suppressed even in such substrates where FR is likely to occur.

[0103] The dry film thickness of the coating is not particularly limited, but is usually 10 to 400 μm, preferably 15 to 300 μm, in order to obtain a coating having sufficient anticorrosion properties. In order to further enhance the effects of the present invention, the lower limit of the dry film thickness of the present coating film is preferably at least 80 μm, more preferably at least 100 μm. When the present coating film has such a thick film thickness, it is possible to form a corrosion-resistant coating film that is resistant to blisters and cracks, and that has a good balance of excellent corrosion resistance, FR suppression, and initial water resistance, even if the coating film comes into contact with water after application of the present composition but before the composition has completely cured.

[0104] The substrate with the coating film of the present invention is a laminate comprising the coating film of the present invention and a substrate, and may be formed with an undercoat coating film (primer coating film) for the purpose of improving adhesion to the substrate and corrosion resistance, an intermediate coating film for the purpose of improving corrosion resistance, and a topcoat coating film that is excellent in weather resistance, aesthetics, etc. Specifically, when the present composition is used as a zinc primer, an intermediate coating film or a topcoat coating film may be formed on the present coating film; when the present composition is used as an intermediate coating, a primer coating film may be formed between the present coating film and the substrate, or a topcoat coating film may be formed on the present coating film; when the present composition is used as a topcoat paint (internal topcoat paint), a primer coating film or an intermediate coating film may be formed between the present coating film and the substrate. Examples of the undercoat coating film include coating films formed from various primer compositions such as epoxy resin-based ones. Examples of the intermediate coating film include coating films formed from various intermediate coating compositions such as (meth)acrylic resin-based, epoxy resin-based, and urethane resin-based ones. Examples of the topcoat coating film include coating films formed from various topcoat coating compositions such as (meth)acrylic resin-based, (meth)acrylic silicone resin-based, urethane resin-based, silicone resin-based, and fluororesin-based ones. Furthermore, the composition of the present composition may be changed to form the undercoat coating film, intermediate coating film, and topcoat coating film using the present composition.

[0105] <Manufacturing method for substrate with anticorrosion coating> The method for producing a substrate with a corrosion-protective coating according to the present invention includes the following steps [1] and [2]. Step [1]: A step of applying the composition to a substrate Step [2]: A step of drying the composition applied to the substrate to form a corrosion-resistant coating film.

[0106] <Process [1]> The coating method in the step [1] is not particularly limited, and examples thereof include conventionally known methods such as spray coating such as airless spray coating and air spray coating, brush coating, roller coating, etc. Among these, spray coating is preferred because it allows for easy coating of large-area substrates such as the structure. In such coating, it is preferable to coat the resulting coating so that the dry film thickness falls within the above range.

[0107] The spray coating conditions may be adjusted as appropriate depending on the desired dry film thickness. For example, in the case of airless spray coating, it is preferable that the primary (air) pressure is about 0.3 to 0.6 MPa, the secondary (paint) pressure is about 10 to 15 MPa, and the gun movement speed is about 50 to 120 cm / sec.

[0108] The coating is preferably carried out so that the dry thickness of the main coating film formed in step [2] falls within the above range. In this case, the main coating film of the desired thickness may be formed by one coating (single coating), or by two or more coatings (two or more coatings). Note that two coats refers to performing steps [1] and [2], and then performing step [1] on the main coating film obtained in step [2].

[0109] When applying the composition to a substrate, it is preferable to treat the surface of the substrate as needed (for example, by blasting (ISO8501-1 Sa2 1 / 2) or degreasing to remove oil and dust) in order to remove rust, oil, moisture, dust, salt, etc. from the substrate and to improve the adhesion of the resulting coating to the substrate. The substrate may also be coated with a shop primer or the like for primary rust prevention.

[0110] <Process [2]> The drying conditions in step [2] are not particularly limited and may be set appropriately depending on the coating film formation method, type of substrate, application, coating environment, etc., but the drying temperature is usually 5 to 35°C in the case of drying at room temperature, and usually 30 to less than 100°C, more preferably 40 to 80°C, in the case of forced drying using a hot air dryer or the like. The present composition can be dried and cured even by drying at room temperature. The drying time varies depending on the drying method of the coating film, and is, for example, about 1 to 7 days when drying at room temperature, and about 5 to 60 minutes when forced drying is used. [Example]

[0111] The present invention will be further described below with reference to examples, but the present invention is not limited to these examples.

[0112] [Example 1] <First agent> 12.5 parts by mass of deionized water, 0.4 parts by mass of anti-sagging agent (Note 5), 1.1 parts by mass of pigment dispersant 1 (Note 1), 1.0 parts by mass of pigment dispersant 2 (Note 2), 0.3 parts by mass of antifoaming agent 1 (Note 3), 0.4 parts by mass of antifoaming agent 2 (Note 4), 18.6 parts by mass of titanium white (Note 6), 0.4 parts by mass of potassium feldspar (Note 7), 8.5 parts by mass of talc (Note 8), and 6.5 parts by mass of anti-rust pigment (Note 9) were placed in a container in this order while stirring using a high-speed disperser at room temperature (23°C), and stirred until the particle size became 50 μm or less, to prepare a pigment dispersion. Next, 1.3 parts by mass of film-forming agent (Note 10), 47.0 parts by mass of epoxy resin (Note 11), 0.5 parts by mass of flash rust control agent 1 (Note 19), and 1.5 parts by mass of multifunctional acrylate (Note 12) were added to the prepared pigment dispersion in that order, and then the mixture was stirred for 15 minutes using a high-speed disperser to prepare the first agent.

[0113] <Second agent> The second agent was prepared by adding 1.82 parts by mass of deionized water, 5.2 parts by mass of amine compound 1 (Note 16), 0.31 parts by mass of flash rust inhibitor 1 (Note 19), and 0.47 parts by mass of flash rust inhibitor 2 (Note 20) in that order, and then stirring for 15 minutes using a high-speed disperser.

[0114] The prepared first and second parts were mixed in the mixing ratio (mass ratio) shown in Table 1 before application to prepare a water-based anticorrosive coating composition.

[0115] [Examples 2 to 15 and Comparative Examples 1 to 15] A water-based anticorrosion coating composition was prepared in the same manner as in Example 1, except that each component shown in Table 1 or 2 was used in the amount (parts by mass) shown in Table 1 or 2. A description of each component listed in Tables 1 and 2 is provided in Table 3.

[0116] The "reaction ratios" in Tables 1 and 2 are values ​​calculated using the above formula (3), and the "functional group ratios" in Tables 1 and 2 are values ​​calculated using the above formula (1). Furthermore, the "amount of PAO chains derived from (meth)acrylate" in Tables 1 and 2 is the content of PAO structures derived from component (D) [or (meth)acrylate compounds] relative to 100% by mass of the nonvolatile content of the aqueous anticorrosive coating composition.

[0117] <Flash rust resistance> An SS400 sandblasted steel plate (arithmetic mean roughness (Ra): 30-75 μm) measuring 150 mm × 70 mm × 4.5 mm (thickness) was prepared. A shop primer (Cerabond 2000 Blue, manufactured by Chugoku Toryo Co., Ltd.) was applied to the entire surface of this steel plate to a dry film thickness of 15 μm, and the plate was allowed to dry at room temperature for 24 hours. A weld bead measuring approximately 100 mm x approximately 10 mm x approximately 5 mm (thickness) was welded to the center of one of the main surfaces of the dried steel plate. The prepared steel plate with weld beads was placed in an exposure test site set up at the Ohtake Research Institute of Chugoku Paint Co., Ltd., with the surface with the bead joined (hereinafter also referred to as the "exposed surface") facing upward at an angle of 0° (so that this surface was approximately perpendicular to gravity), and tap water was constantly sprayed on the steel plate with weld beads for three days (spray exposure treatment). The entire exposed surface of the dried steel plate with weld beads was then polished using a wire brush until it reached the ISO8501-1 St-3 grade, and dust, dirt, and other debris were removed from areas other than those with rust using a simple disk sander.

[0118] The aqueous anticorrosion coating composition prepared as described above was applied to the entire exposed surface of the steel plate with weld beads treated in this manner using an air spray so that the dry film thickness was 100 μm, thereby producing an aqueous anticorrosion coating composition-coated substrate (hereinafter also referred to as "test piece 1").

[0119] A container filled with water was placed in the sealed container to maintain high humidity, and the sealed container was then sealed and allowed to stand at a temperature of 40±3°C for 24 hours. Within 2 minutes of applying the aqueous anticorrosive coating composition, the prepared test piece 1 was placed in the sealed container, ensuring that the aqueous anticorrosive coating composition did not come into contact with the water or the sealed container, and the sealed container was then sealed again. After leaving the test piece at 40±3°C for 24 hours, the flash rust resistance was evaluated according to the following evaluation criteria. The results are shown in Tables 1 and 2.

[0120] (Evaluation criteria) ○: No rust is observed on the surface of the substrate under the application of the water-based anticorrosive coating composition △: Rust is observed on part of the substrate surface under the application of the water-based anticorrosive coating composition ×: Rust is observed on the entire surface of the substrate under the application of the water-based anticorrosive coating composition

[0121] <Initial water resistance> An SS400 sandblasted steel plate (arithmetic mean roughness (Ra): 30 to 75 μm) measuring 150 mm × 70 mm × 2.3 mm (thickness) was prepared. The water-based anticorrosion coating composition prepared as described above was applied to the surface of this steel plate using an air spray to a dry film thickness of 100 μm, thereby producing a water-based anticorrosion coating composition-coated substrate (hereinafter also referred to as "test piece 2").

[0122] Immediately after painting, test piece 2 was dried at a temperature of 5±3°C for 24 hours to form an anticorrosion coating, and then immersed in water at a temperature of 5±3°C for 24 or 72 hours. The appearance of test piece 2 after immersion was then visually evaluated based on the following evaluation criteria for blisters and cracks. The results are shown in Tables 1 and 2.

[0123] (Evaluation criteria for blister) ◎: No blisters are observed on the anticorrosion coating film on test piece 2 ○: Blisters are observed in less than 3% of the total area of ​​the anticorrosion coating on test piece 2 △: Blisters are observed in 3% to less than 50% of the total area of ​​the anticorrosion coating on test piece 2. ×: Blisters are observed in 50% or more of the total area of ​​the anticorrosive coating film on test panel 2 XX: The anticorrosion coating film on test plate 2 peeled off from the substrate.

[0124] (Crack evaluation criteria) ◎: No cracks (breaks) were observed in the anticorrosive coating on test piece 2 ○: Cracks (cracking) were observed in less than 10% of the total area of ​​the anticorrosion coating on test piece 2 △: Cracks (fractures) were observed in 10% to less than 50% of the total area of ​​the anticorrosive coating on test piece 2. ×: Cracks (cracking) were observed in 50% or more of the total area of ​​the anticorrosive coating on test panel 2. XX: The anticorrosion coating film on test plate 2 peeled off from the substrate.

[0125] <Salt spray resistance> An SS400 sandblasted steel plate (arithmetic mean roughness (Ra): 30 to 75 μm) measuring 150 mm × 70 mm × 2.3 mm (thickness) was prepared. The water-based anticorrosion coating composition prepared as described above was applied to the surface of this steel plate using an air spray to a dry film thickness of 100 μm, and the coating was dried at 23°C for 7 days to produce a substrate with an anticorrosion coating (hereinafter also referred to as "test piece 3").

[0126] A salt spray test was conducted in accordance with JIS K 5600-7-1:1999 by holding the prepared test piece 3 in a salt spray tester under salt spray conditions of 5% by mass salt water, 35°C temperature, and 98% relative humidity for 400 hours, and the salt spray resistance (corrosion resistance) was evaluated according to the following evaluation criteria. The results are shown in Tables 1 and 2. In addition, if the salt spray resistance (corrosion resistance) is evaluated as ○, there is no problem.

[0127] (Evaluation criteria) ○: Blisters occurred in less than 3% of the total area of ​​the anticorrosive coating on test piece 3, and / or the area ratio of rust on the substrate surface under the anticorrosive coating was less than 0.03% of the 100% area of ​​the substrate under the anticorrosive coating. △: Blisters occurred in 3% or more but less than 50% of the total area of ​​the anticorrosive coating on the test piece 3, and / or the area ratio of rust on the surface of the substrate under the anticorrosive coating was 0.03% or more but less than 0.3% of the 100% area of ​​the substrate under the anticorrosive coating. ×: Blisters occurred in 50% or more of the total area of ​​the anticorrosive coating on the test piece 3, and / or the area ratio of rust on the surface of the substrate under the anticorrosive coating was 0.3% or more relative to 100% of the area of ​​the substrate under the anticorrosive coating.

[0128] [Table 1]

[0129] [Table 2]

[0130] [Table 3]

Claims

1. The composition contains an epoxy resin (A), an amine compound (B), a flash rust inhibitor (C), and a polyfunctional (meth)acrylate (D). A water-based anticorrosion coating composition for forming an anticorrosion coating film with a dry film thickness of 80 μm or more.

2. a first agent containing the epoxy resin (A) and a polyfunctional (meth)acrylate (D); a second agent containing the amine compound (B) and the flash rust inhibitor (C); The water-based anticorrosion coating composition according to claim 1, comprising:

3. 3. The aqueous anticorrosive coating composition according to claim 1, wherein the polyfunctional (meth)acrylate (D) is a tri- or higher functional (meth)acrylate compound.

4. 4. The aqueous anticorrosive coating composition according to claim 1, wherein the functional group ratio represented by the following formula (1) is 0.010 to 0.30: Functional group ratio=(amount of the solid content of the polyfunctional (meth)acrylate (D) / functional group equivalent of the solid content of the polyfunctional (meth)acrylate (D)) / (amount of the solid content of the amine compound (B) / active hydrogen equivalent of the solid content of the amine compound (B)) (1)

5. The water-based anticorrosive coating composition according to any one of claims 1 to 4, which is for use on a substrate having a welded portion.

6. A corrosion-resistant coating film having a dry thickness of 80 μm or more, formed from the aqueous corrosion-resistant coating composition according to any one of claims 1 to 5.

7. A substrate with a corrosion-protective coating, comprising the corrosion-protective coating according to claim 6 and a substrate.

8. The substrate with a corrosion-protective coating according to claim 7 , wherein the substrate has a weld.

9. A method for producing a substrate with a corrosion-protective coating, comprising the following steps [1] and [2]: [1] A step of coating a substrate with the aqueous anticorrosive coating composition according to any one of claims 1 to 5. [2] A step of drying the applied water-based anticorrosion coating composition to form an anticorrosion coating film with a dry film thickness of 80 μm or more.

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