Water-based paint composition kit, coating film, substrate with coating film, and method for producing substrate with coating film

Abstract

To provide a kit for a water-based coating composition, which can obtain a water-based coating composition excellent in low-temperature drying and curing properties and can form a coating film having a good balance between initial water resistance and impact resistance. [Solution] This is a multi-component water-based coating composition kit that includes a first part containing an aqueous epoxy resin (A) and a second part containing an amine curing agent (B), and also contains a silane coupling agent (C) and water, wherein the solid content of the silane coupling agent (C) in the water-based coating composition is 0.05 to 0.60 parts by mass per part by mass of water in the water-based coating composition.

Description

[Technical Field]

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

[0002] BACKGROUND ART For the purpose of using substrates such as ships, marine structures, plants, bridges, and land tanks for a long period of time, coating compositions such as solvent-based epoxy resin anticorrosive coatings have been conventionally applied to these substrates.

[0003] In recent years, with the strengthening of regulations on organic solvent emissions aimed at considering the natural environment, the painting work environment, etc., efforts are being made to reduce the VOC (volatile organic compound) content of paint compositions such as those mentioned above. One method for reducing VOCs is to make paint compositions water-based. Water-based paint compositions use water primarily as a solvent and dispersion medium, so they can significantly reduce VOCs compared to conventional solvent-based paint compositions while maintaining appropriate paint viscosity.

[0004] On the other hand, because water-based paint compositions contain water, a phenomenon known as flash rust is likely to occur, in which rust forms between the time the paint is applied and the time it dries to form a film. As an example of a water-based paint composition that can suppress such flash rust, Patent Document 1 discloses a water-based paint composition that includes a first agent containing a rust inhibitor and a second agent that contains a flash rust inhibitor but no rust inhibitor, and also includes an aqueous resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-122114 Summary of the Invention [Problem to be solved by the invention]

[0006] The present inventors have conducted extensive research and found that although the aqueous coating composition described in Patent Document 1 can suppress flash rust, there is room for improvement in its dry-curing properties at low temperatures (e.g., 5°C) (low-temperature dry-curing properties), and that this reduced low-temperature dry-curing properties can lead to a decrease in the initial water resistance of the coating film formed. Specifically, it has been found that if the aqueous coating composition described in Patent Document 1 is applied to a substrate outdoors in winter, and then water comes into contact with the coated substrate due to rainfall or the like, abnormalities such as blisters can occur in the formed coating film. Furthermore, the coating film formed on the substrate from the water-based coating composition may be required to have properties such as impact resistance.

[0007] The present invention has been made in view of the above, and an object of the present invention is to provide a kit for an aqueous paint composition, which can obtain an aqueous paint composition that has excellent low-temperature drying and curing properties, and can form a coating film that has a good balance of initial water resistance and impact 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 first agent containing an aqueous epoxy resin (A), a second part containing an amine curing agent (B); a multi-component water-based coating composition kit containing a silane coupling agent (C) and water, The content of the solid content of the silane coupling agent (C) in the aqueous coating composition is 0.05 to 0.60 parts by mass per part by mass of water in the aqueous coating composition. Kit for water-based paint composition.

[0010] [2] The kit for an aqueous coating composition according to [1], wherein the content of the solid content of the silane coupling agent (C) in the aqueous coating composition is 0.07 to 1.2 parts by mass per 1 part by mass of the solid content of the aqueous epoxy resin (A) in the aqueous coating composition.

[0011] [3] The kit for an aqueous coating composition according to [1] or [2], wherein the content of the solid content of the silane coupling agent (C) in the aqueous coating composition is 0.05 to 0.80 parts by mass per 1 part by mass of the total of the solid content of the aqueous epoxy resin (A) and the solid content of the amine curing agent (B) in the aqueous coating composition.

[0012] [4] The kit for an aqueous coating composition according to any one of [1] to [3], wherein the content of the solid content of the silane coupling agent (C) in the aqueous coating composition is 0.03 to 0.25 parts by mass per 1 part by mass of the non-volatile content of the aqueous coating composition.

[0013] [5] The kit for an aqueous paint composition according to any one of [1] to [4], wherein the water content in the aqueous paint composition is 5 to 50 mass %.

[0014] [6] The kit for an aqueous paint composition according to any one of [1] to [5], wherein the content of non-volatile matter in the aqueous paint composition is 40 to 95 mass %.

[0015] [7] A coating film formed using the kit for a water-based coating composition according to any one of [1] to [6]. [8] A substrate with a coating film comprising a substrate and the coating film according to [7].

[0016] [9] A method for producing a substrate with a coating film, comprising the following steps I and II: Step I: A step of applying to a substrate an aqueous coating composition obtained using the kit for an aqueous coating composition according to any one of [1] to [6]. Step II: A step of drying the water-based coating composition applied to the substrate to form a coating film [Effects of the Invention]

[0017] According to the present invention, it is possible to obtain a water-based coating composition that has excellent low-temperature drying and curing properties, and to form a coating film that has a good balance of initial water resistance and impact resistance. Furthermore, according to the present invention, it is possible to easily obtain a composition that has excellent low-temperature drying curing properties and a relatively long pot life. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic plan view (schematic explanatory diagram) of a glass plate on which a coating film has been formed, viewed from above the coating film side, in a test of drying and curing properties in the following Examples. DETAILED DESCRIPTION OF THE INVENTION

[0019] <Water-based paint composition kit> The kit for the aqueous paint composition (hereinafter also referred to as "the composition") according to the present invention (hereinafter also referred to as "the kit") comprises: a first agent containing an aqueous epoxy resin (A); a second part containing an amine curing agent (B); a multi-component kit containing a silane coupling agent (C) and water, The content of the solid content of the silane coupling agent (C) in the composition is 0.05 to 0.60 parts by mass per 1 part by mass of water in the composition. It's a kit.

[0020] According to this kit, it is possible to obtain a composition that has excellent low-temperature drying and curing properties, and to form a coating film that has a good balance of excellent initial water resistance and impact resistance. Furthermore, while paint compositions that generally have excellent low-temperature drying and curing properties often have a short pot life, contrary to this common technical knowledge, the present kit makes it possible to easily obtain a composition that has excellent low-temperature drying and curing properties while also having a relatively long pot life. The reason why the present kit exhibits such effects is not entirely clear, but is speculated to be as follows. In this composition, hydrolysis of the silane coupling agent occurs in the presence of water within a relatively short time after preparation, and the hydrolyzate then condenses and oligomerizes. Once the oligomer reaches a certain molecular weight, the condensation slows down, which is thought to be step (i). Then, by painting or otherwise applying this composition after step (i), the specific surface area of ​​the composition increases, which is thought to be step (ii) in which water evaporates. This water evaporation increases the pH of the composition, accelerating the condensation of the silane coupling agent again. At the same time, the reaction of functional groups in the silane coupling agent that can react with organic substances (e.g., epoxy groups, amino groups) is thought to proceed. By taking these steps (i) and (ii), the composition is thought to have excellent drying and curing properties even under low-temperature conditions where the reaction between the epoxy resin and the amine curing agent is unlikely to proceed. However, when stored in a container or the like (before step (ii) is performed), the specific surface area of ​​the composition is small, so water is unlikely to evaporate, accelerating the re-condensation of the silane coupling agent and the functional groups (e.g., epoxy groups, amino groups) that can react with organic substances in the silane coupling agent are unlikely to react. Therefore, it is thought that the composition can have a relatively long pot life.

[0021] This composition can be obtained by mixing the first agent, the second agent, and an nth agent (n is 3 or more) other than the first agent and the second agent, which is optionally used, in this kit. The present kit is preferably a two-component kit consisting of the first agent and the second agent, or a three-component kit consisting of the first agent, the second agent, and a third agent.

[0022] The first agent, second agent, and nth agent constituting this kit are usually stored, preserved, transported, etc. in separate containers, and are mixed together immediately before use of the composition.

[0023] The first agent is preferably prepared by the following step 1. The second agent is preferably prepared by the following step 2. The agent n is preferably prepared by the following step 3.

[0024] <Present composition> The composition is obtained from the kit. The present composition is also capable of forming a coating film with excellent corrosion resistance, and therefore, one embodiment of the present composition is preferably a water-based anticorrosion coating composition. The present composition has excellent coating workability and can be applied by a variety of conventionally known coating methods, but because of its excellent spray coating workability, it is preferably used for spray coating.

[0025] The content of nonvolatile matter in the present composition is preferably 40 to 95 mass %, more preferably 45 to 95 mass %, and even more preferably 50 to 90 mass %. The present composition, whose nonvolatile content is within the above range, has excellent low-temperature drying and curing properties, is less likely to sag when applied, can form a thick film with a single application, and can easily be obtained with excellent application workability.

[0026] The content of nonvolatile matter in the present composition may be a value calculated from the solid content of the raw materials used, or may be a measured value. Specifically, the measured value is 1±0.1 g of the composition (the composition immediately after mixing the first agent and the second agent (and the nth agent if an nth agent is included)) weighed out onto a flat-bottom dish, spread evenly using a wire of known mass, dried at 23°C for 24 hours, and then heated at a heating temperature of 125°C for 1 hour (at normal pressure) to obtain the mass (including the mass of the wire) after which the mass of the non-volatile components (heat residue) is calculated as a percentage of the mass of the composition initially weighed out.

[0027] In this specification, among the components (e.g., silane coupling agent (C)) that are raw materials constituting this composition, the components other than the solvent and dispersion medium (e.g., water) in the first, second, and nth agents that have a boiling point of less than 180°C under normal pressure are referred to as "solids."

[0028] The semi-curing time of the present composition (the time from immediately after the formation of the coating film until the coating film is semi-cured at a temperature of 5°C) is preferably 10 hours or less, more preferably 8 hours or less, and the lower limit is preferably 0.5 hours. The present composition having a half-curing time within the above range can be said to have excellent low-temperature drying and curing properties. The semi-curing time is measured by the method described in the section on dry curing properties in the Examples below.

[0029] [Silane coupling agent (C)] The composition contains a silane coupling agent (C). The silane coupling agent (C) may be blended into the first agent, the second agent, or the nth agent, or may be blended into at least two or more agents selected from the first agent to the nth agent. The silane coupling agent (C) used in the present composition may be one type or two or more types.

[0030] The silane coupling agent (C) is not particularly limited, and any conventionally known compound can be used, but it is preferable that the silane coupling agent (C) is a compound that has at least two functional groups in the same molecule and can contribute to improving adhesion to the substrate and reducing the viscosity of the composition.

[0031] The silane coupling agent (C) is preferably, for example, a compound represented by the following formula (1). X-SiMe n Y 3-n ···(1) [n is 0 or 1, X is a functional group capable of reacting with organic substances (e.g., amino group, vinyl group, epoxy group, mercapto group, halogeno group, a group in which a hydrocarbon group is partially substituted with one of these groups, or a group in which a hydrocarbon group is partially substituted with an ether bond or the like and then partially substituted with one of these groups), Me is a methyl group, and Y is a hydrolyzable group (e.g., an alkoxy group such as a methoxy group or an ethoxy group).]

[0032] When a silane coupling agent that is reactive with the amine curing agent (B), such as an epoxy group-containing silane coupling agent, is used, the silane coupling agent is preferably blended in the first part or the nth part. Furthermore, when a silane coupling agent reactive with the aqueous epoxy resin (A), such as an amino group-containing silane coupling agent, is used, the silane coupling agent is preferably blended in the second part or the nth part.

[0033] Among the silane coupling agents (C), it is preferable to use an epoxy group-containing silane coupling agent in which X is an epoxy group, a group in which a hydrocarbon group is partly substituted with an epoxy group, or a group in which a hydrocarbon group is partly substituted with an ether bond or the like and partly substituted with an epoxy group.

[0034] Commercially available silane coupling agents may be used, such as 3-glycidoxypropyltrimethoxysilane "KBM-403" (manufactured by Shin-Etsu Chemical Co., Ltd.), "Sila-Ace S-510" (manufactured by JNC Corporation), 3-aminopropyltrimethoxysilane "KBM-903" (manufactured by Shin-Etsu Chemical Co., Ltd.), and 3-aminopropylsilane hydrolysate "Dynasylan Hydrosil 1153" (manufactured by Evonik Industries).

[0035] The solid content of the silane coupling agent (C) in the composition is 0.05 to 0.60 parts by mass, preferably 0.06 to 0.60 parts by mass, more preferably 0.07 to 0.60 parts by mass, and particularly preferably 0.10 to 0.50 parts by mass, per part by mass of water in the composition. When the content is within the above range, it is possible to easily obtain a composition having excellent low-temperature drying curing properties and a relatively long pot life, and to easily form a coating film having excellent initial water resistance.

[0036] The solid content of the silane coupling agent (C) in the composition is preferably 0.07 to 1.2 parts by mass, more preferably 0.10 to 1.0 parts by mass, and particularly preferably 0.15 to 0.90 parts by mass per part by mass of the solid content of the aqueous epoxy resin (A) in the composition. When the content is within the above range, the present composition can be easily obtained, which is particularly excellent in low-temperature drying and curing properties.

[0037] The content of the solid content of the silane coupling agent (C) in the composition is preferably 0.05 to 0.80 parts by mass, more preferably 0.10 to 0.80 parts by mass, and particularly preferably 0.12 to 0.60 parts by mass per 1 part by mass of the total of the solid content of the aqueous epoxy resin (A) and the solid content of the amine curing agent (B) in the composition. When the content is within the above range, the present composition can be easily obtained, which is particularly excellent in low-temperature drying and curing properties.

[0038] The solid content of the silane coupling agent (C) in the present composition is preferably 0.03 to 0.25 parts by mass, and more preferably 0.04 to 0.20 parts by mass, per 1 part by mass of the nonvolatile content of the present composition. When the content is within the above range, the present composition can be easily obtained, which is particularly excellent in low-temperature drying and curing properties.

[0039] When an amino group-containing silane coupling agent is used as the silane coupling agent (C), Y M / Y B is preferably less than 0.8, and more preferably 0.7 or less. where: Y M is the value obtained by dividing the blend amount (mass%) of the solid content of the amino group-containing silane coupling agent contained in the composition by the active hydrogen equivalent of the solid content of the amino group-containing silane coupling agent, Y B is the value obtained by dividing the amount (mass %) of the solid content of the amine curing agent (B) contained in the composition by the active hydrogen equivalent of the solid content of the amine curing agent (B).

[0040] [water] The composition contains water. The water may be blended into the first agent, the second agent, or the nth agent, or may be blended into at least two or more agents selected from the first agent to the nth agent. At least one selected from the first agent and the second agent preferably contains water, more preferably the second agent contains water, and even more preferably both the first agent and the second agent contain water.

[0041] Water may be contained in raw materials such as the raw materials for the aqueous epoxy resin (A) used in preparing the first part and the raw materials for the amine curing agent (B) used in preparing the second part. When using such water-containing raw materials, it is not necessary to use water other than the water contained in the raw materials, but it is preferable to use water in addition to the water that may be contained in these raw materials, from the viewpoints of making it easier to prepare the present composition and easily obtaining the present composition with superior coating workability. The water to be further used is not particularly limited, and tap water or the like may be used, but ion-exchanged water, distilled water, or the like is preferably used.

[0042] When the first agent contains water, the content of water in the first agent (including water that may be contained in raw materials such as the raw materials for the aqueous epoxy resin (A)) is preferably 4 to 80 mass %, more preferably 10 to 70 mass %, and even more preferably 20 to 50 mass %, from the viewpoints of the viscosity of the coating material, anti-settling properties, etc. 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. In this specification, the silane coupling agent does not fall under the category of a dispersion medium.

[0043] When the second part contains water, the content of water in the second part (including water that may be contained in raw materials such as raw materials for the amine curing agent (B)) is preferably 5 to 95% by mass, more preferably 10 to 90% by mass, from the viewpoint that the desired composition of the present invention can be easily obtained. 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.

[0044] It is preferable to use water so that the content of nonvolatile matter in the present composition falls within the above range. The content of water in the present composition is preferably 5 to 50% by mass, more preferably 10 to 50% by mass, from the viewpoint that the desired present composition can be easily obtained.

[0045] <Method for producing the present composition> The method for producing the present composition (hereinafter also referred to as "the method") is as follows: Step 1: preparing a first agent using an aqueous epoxy resin (A); Step 2: preparing a second part using an amine curing agent (B); If necessary, step 3 of preparing agent n; Step 4: Mixing the first agent prepared in step 1, the second agent prepared in step 2, and, if necessary, the nth agent prepared in step 3; (However, in at least one of the steps 1 to 3, a silane coupling agent (C) and water are used).

[0046] <Process 1> The step 1 is a step of preparing a first agent using the aqueous epoxy resin (A). Step 1 is not particularly limited as long as an aqueous epoxy resin (A) is used. The aqueous epoxy resin (A) itself may be used as the first agent (in this case, step 1 can also be said to be a step of using the aqueous epoxy resin (A)), or it may be a step of mixing the aqueous epoxy resin (A) with other components described below, but the latter is preferred. In the latter case, step 1 is specifically a step of mixing (or kneading) each component to be blended into the first agent, and during this mixing (or kneading), each component may be added and mixed at once, or may be added and mixed in multiple batches. The mixing (or 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 (or kneading) may be carried out while heating or cooling depending on the season, environment, etc.

[0047] [Water-based epoxy resin (A)] Specific examples of the water-based epoxy resin (A) include water or an epoxy resin that uses water as the main solvent or dispersion medium, or an epoxy resin that can be mixed with water (can be diluted with water), and more specific examples include water-dispersible epoxy resins, water-soluble epoxy resins, and self-emulsifying epoxy resins. It may be impossible to determine whether or not these aqueous epoxy resins (A) are aqueous epoxy resins after mixing with other components that may be contained in the first agent, for example. However, even in such cases, when the aqueous epoxy resin (A) is used as a raw material for preparing the first agent or the like, the present invention refers to the aqueous epoxy resin (A) being included. The aqueous epoxy resin (A) used in the present composition may be one type or two or more types.

[0048] The aqueous epoxy resin (A) used as a raw material for the first agent is not particularly limited, but is preferably an epoxy resin emulsion or an epoxy resin dispersion, and more preferably an epoxy resin emulsion. The epoxy resin emulsion may be, for example, an emulsion in which oil droplets containing an epoxy resin are uniformly dispersed in an aqueous medium.

[0049] Epoxy resin emulsions can be prepared by forcibly emulsifying an epoxy resin in an aqueous medium, for example, by a phase inversion temperature emulsification method or a mechanical emulsification method. Examples of emulsifiers that can be used include alkyl-type and alkylphenol-type nonionic surfactants; and anionic surfactants such as phosphate esters, alkylbenzene sulfonates, and sulfosuccinates. These emulsifiers may be used alone or in combination of two or more.

[0050] The epoxy resin may be a modified epoxy resin in consideration of the water resistance of the coating film to be formed and in order to reduce the amount of emulsifier used. Examples of such modification include bonding the epoxy resin with another compound to introduce an emulsifying segment into the molecule to modify the epoxy resin into a self-emulsifying epoxy resin. More specifically, examples include introducing at least one group selected from a polyoxyalkylene chain, a hydroxyl group, an amino group, and a carboxyl group into the epoxy resin. These modified epoxy resins may be used alone or in combination of two or more.

[0051] Examples of the epoxy resin include bisphenol epoxy resins, novolac epoxy resins (e.g., phenol novolac epoxy resins, cresol novolac epoxy resins), and alicyclic epoxy resins. Among these, bisphenol epoxy resins are preferred because they can provide a coating film with superior corrosion resistance. Examples of bisphenol-type epoxy resins include copolymers obtained using a compound having a bisphenol skeleton and epihalohydrin, and more specifically, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol AD-type epoxy resins, etc. Among these, bisphenol A-type epoxy resins are preferred because they can provide coating films with superior corrosion resistance. These epoxy resins may be used alone or in combination of two or more.

[0052] As the epoxy resin emulsion, commercially available products may be used, and examples of such commercially available products include Yuka Resin NEP-1110 (manufactured by Yoshimura Oil Chemical Co., Ltd.), Adeka Resin EM-101-50 (manufactured by ADEKA Corporation), BECKOPOX C-200 EP, and BECKOPOX EP 384w / 53WAMP (all manufactured by Allnex Germany GmbH).

[0053] The epoxy equivalent weight per solid content of the epoxy resin is preferably 150 to 6,000, more preferably 400 to 3,000, from the viewpoint of being able to easily form a coating film that is excellent in low-temperature drying curing properties and corrosion resistance.

[0054] The content of the epoxy resin in 100% by mass of the aqueous epoxy resin (A) is preferably 35 to 100% by mass, more preferably 45 to 100% by mass, from the viewpoint that the present composition having excellent ease of preparation, storage stability, etc. can be easily obtained. The remainder of the aqueous epoxy resin (A) other than the epoxy resin may contain water, and may contain conventionally known components such as surfactants, if necessary.

[0055] The solid content of the aqueous epoxy resin (A) in the present composition is preferably 10 to 70 mass%, more preferably 15 to 60 mass%, relative to 100 mass% of the nonvolatile content of the present composition, from the viewpoint of being able to easily form a coating film with excellent corrosion resistance, etc. For the same reason, the solid content of the aqueous epoxy resin (A) in the first agent is preferably 10 to 70 mass %, more preferably 15 to 65 mass %, relative to 100 mass % of the solid content of the first agent.

[0056] [Other ingredients] In step 1, if desired, other components than the aqueous epoxy resin (A), such as a silane coupling agent (C), water, a flash rust inhibitor, a pigment, a pigment dispersant, an antifoaming agent, a viscosity modifier (anti-sagging agent, anti-settling agent, thixotropic agent), a reactive diluent, a plasticizer, a curing accelerator, a dehydrating agent, a film-forming aid, an organic solvent, etc., may be used within the range that does not impair the effects of the present invention (the first agent may contain the other components). These other components may each be used alone or in combination of two or more.

[0057] As the other components, conventionally known components can be used. As the other components, commercially available products may be used, and in this case, the commercially available products may be for solvent systems and for aqueous systems. When water is blended into the first agent to make the first agent an aqueous system, it is preferable to use commercially available products for aqueous systems as the other components used in the first agent, and when an organic solvent is blended into the first agent to make the first agent an organic solvent system, it is preferable to use commercially available products for solvent systems as the other components used in the first agent.

[0058] <Flash rust inhibitor> When the present composition is applied to a metal surface, the rust on the metal surface may bleed onto the surface of the coating film, causing rust spots (flash rust), and this can be prevented by incorporating a flash rust inhibitor into the present composition. The flash rust inhibitor is not particularly limited as long as it is a component that can inhibit flash rust, and any known flash rust inhibitor can be used.

[0059] Examples of flash rust inhibitors 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; salts of fatty acids such as sebacic acid and dodecanoic acid; phosphoric acid derivatives such as alkyl phosphates and polyphosphates; tannates; metal sulfonates; N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), di Examples of suitable chelating agents include amine-based chelating agents such as ethylenetriaminepentaacetic acid (DTPA), propylenediaminetetraacetic acid (PDTA), iminodiacetic acid, nitrilotriacetic acid (NTA), diethylenetriaminepentamethylenephosphonic acid (DTPMP), and alkali metal salts thereof; addition reaction products obtained by using 4-methyl-γ-oxo-benzenebutanoic acid and N-ethylmorpholine; intercalation compounds obtained by intercalating monoalkylamines, polyamines, and / or quaternary ammonium ions into layered phosphates such as aluminum dihydrogen tripolyphosphate; and hydrazine derivatives such as hydrazide compounds, semicarbazide compounds, and hydrazone compounds.

[0060] Commercially available products may be used as the flash rust inhibitor, and examples of such commercially available products include "Killesrite W-410" and "Killesrite W-16B" (both manufactured by Chelest Co., Ltd. / organic acid salt type), and "HALOX FLASH-X 150" (manufactured by ICL Additives-Hammond / nitrite, benzoate type).

[0061] When a flash rust inhibitor is blended with the present composition, the amount of the flash rust inhibitor blended is preferably 0.01 to 5 mass %, more preferably 0.05 to 3 mass %, relative to 100 mass % of the nonvolatile content of the present composition, in order to facilitate the formation of a coating film in which flash rust is further suppressed. When a flash rust inhibitor is blended in the first agent, the blending amount of the flash rust inhibitor is preferably 0.01 to 5 mass %, more preferably 0.05 to 3 mass %, relative to 100 mass % of the solid content of the first agent.

[0062] Pigments Examples of pigments include extender pigments, coloring pigments, and anti-rust pigments, and they may be either organic or inorganic.

[0063] 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. Among these, talc, mica, silica, (precipitated) barium sulfate, and (potassium) feldspar are particularly preferred.

[0064] When an extender pigment is blended in the present composition, the blending amount of the extender pigment is preferably 1 to 80 mass %, more preferably 5 to 70 mass %, relative to 100 mass % of the nonvolatile content of the present composition.

[0065] 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. Of these, titanium white, carbon black, and red iron oxide are particularly preferred.

[0066] When a color pigment is blended in the present composition, the blending amount of the color pigment is preferably 0.1 to 50% by mass, more preferably 1 to 40% by mass, relative to 100% by mass of the nonvolatile content of the present composition.

[0067] Examples of the rust-preventive pigment include zinc powder, zinc alloy powder, 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.

[0068] When an anti-rust pigment is blended in the present composition, the blending amount of the anti-rust pigment is preferably 0.5 to 20 mass %, more preferably 1 to 10 mass %, based on 100 mass % of the non-volatile content of the present composition.

[0069] When a pigment is blended in the present composition, it is desirable to use the pigment so that the pigment mass concentration (PWC) in the present composition is preferably 20 to 80%, more preferably 30 to 75%. When the PWC is within the above range, the present composition can be easily obtained with excellent coating workability, and a coating film can be easily formed with excellent adhesion to the substrate and corrosion resistance due to stress relaxation.

[0070] The PWC in the present composition refers to the total mass concentration of pigments relative to the mass of the nonvolatile content of the present composition, and can be specifically calculated by the following formula (2). PWC [%] in the composition = total mass of all pigments in 100% by mass of the composition × 100 / content of nonvolatile matter in the composition (% by mass) (2)

[0071] The nonvolatile content (mass%) in the present composition may be a measured value or a value calculated from the solid content of the raw materials used, as measured by the method described in the section on the present composition. The total mass of all pigments in 100% by mass of the present composition may be a measured value or a value calculated from the raw materials used. The measured value can be calculated, for example, by separating the pigments and other components from the nonvolatile content of the present composition and measuring the mass of the separated pigments.

[0072] <Dispersant> The pigment is preferably dispersed in the composition, and therefore a dispersant is preferably added to the agent for blending the pigment. Examples of the dispersant include various known organic or inorganic pigment dispersants, such as copolymers having a pigment-adsorbing group (pigment-affinity group) such as a carboxyl group, a phosphate group, an amino group, a salt group of these, or an ammonium base, and having a compatible chain such as a fatty acid, polyamino, polyether, polyester, polyurethane, or polyacrylate.

[0073] When a dispersant is blended into the present composition, the amount of solid content of the dispersant blended is preferably 0.1 to 5 mass %, more preferably 0.1 to 3 mass %, relative to 100 mass % of the nonvolatile content of the present composition, in order to facilitate the formation of a coating film with excellent smoothness and a uniformly dispersed pigment.

[0074] <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 any bubbles that have generated in the present composition, thereby making it possible to easily form a coating film having the desired physical properties.

[0075] Commercially available antifoaming agents may be used, such as "BYK-392," "BYK-066N," "BYK-1770," and "BYK-1790" (all manufactured by BYK Japan K.K.), "TEGO Airex 902W" (manufactured by Evonik Industries), and "Spectrasyn 40" (manufactured by ExxonMobil Chemical Company).

[0076] When an antifoaming agent is blended into the present composition, the amount of the solid content of the antifoaming agent is preferably 0.005 to 1 mass %, more preferably 0.01 to 0.5 mass %, relative to 100 mass % of the nonvolatile content of the present composition, in order to sufficiently suppress foam generation and easily form a coating film with the desired physical properties.

[0077] Viscosity adjusters (anti-sagging agents, anti-settling agents, thixotropic agents) Viscosity adjusters (also called anti-sagging agents, anti-settling agents or thixotropic agents; hereinafter collectively referred to as "viscosity adjusters") include Al, Ca, Zn stearate salts, lecithin salts, organic clay waxes such as alkylsulfonates, polyethylene waxes, Conventionally known viscosity modifiers can be used, such as amide viscosity modifiers, amide neutralized salt viscosity modifiers, mixtures of amide viscosity modifiers, urea viscosity modifiers, hydrogenated castor oil wax, mixtures of hydrogenated castor oil wax and amide wax, synthetic finely powdered silica, and oxidized polyethylene wax. Of these, amide wax, synthetic finely powdered silica, oxidized polyethylene wax, and organic clay wax are preferred.

[0078] As the viscosity adjuster, commercially available products may be used, and examples of such commercially available products include "Disparlon 305," "Disparlon 4200-20," and "Disparlon 6650" manufactured by Kusumoto Chemical Co., Ltd.; "ASA T-250F" manufactured by Ito Oil Milling Co., Ltd.; "Flonon RCM-300" manufactured by Kyoeisha Chemical Co., Ltd.; and "BENTONE DE" and "BENTONE SD-2" manufactured by Elementis Specialties, Inc.

[0079] When a viscosity adjuster is blended into the present composition, the viscosity of the composition can be adjusted, the settling of pigments and the like during storage of the composition can be easily suppressed, and sagging during application can be easily suppressed. From these viewpoints, the blending amount of the solid content of the viscosity adjuster is preferably 0.5 to 4 mass% relative to 100 mass% of the nonvolatile content of the present composition.

[0080] <Film-forming agent> Since the present composition contains water, the composition may freeze in winter, etc., and from the viewpoint of improving film-forming properties at low temperatures and the finished appearance of the resulting coating film, a film-forming aid may be blended.

[0081] The film-forming aid may be any of those typically used in aqueous paint compositions, such as organic compounds with a boiling point of 180°C or higher at room temperature. Examples of such film-forming aids 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.

[0082] When a film-forming aid is blended into the present composition, the blending amount of the film-forming aid is preferably 0.5 to 10 mass %, more preferably 1 to 8 mass %, relative to 100 mass % of the present composition, in order to facilitate the formation of a coating film that has excellent film-forming properties and appearance at low temperatures.

[0083] <Organic solvents> The present composition is an aqueous coating composition containing water, but at least one of the first agent, the second agent, and the nth agent may be an organic solvent-based agent containing an organic solvent (however, this does not include the case where all of the first agent, the second agent, and the nth agent are organic solvent-based agents).

[0084] The organic solvent is preferably an organic solvent having 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, and aliphatic hydrocarbon solvents such as n-hexane, n-octane, 2,2,2-trimethylpentane, isooctane, n-nonane, cyclohexane and methylcyclohexane.

[0085] When an organic solvent is blended in the present composition, it is preferable to use the organic solvent so that the content of nonvolatile matter in the present composition falls within the above range.

[0086] <Process 2> The step 2 is a step of preparing a second part using an amine curing agent (B). Step 2 is not particularly limited as long as an amine curing agent (B) is used. The amine curing agent (B) itself may be used as the second agent (in this case, step 2 can also be said to be a step of using the amine curing agent (B)), or it may be a step of mixing the amine curing agent (B) with other components described below, but the latter is preferred. In the latter case, step 2 is specifically a step of mixing (or kneading) each component to be blended into the second agent, and during this mixing (or kneading), each component may be added and mixed at once, or may be added and mixed in multiple batches. The mixing (or 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 (or kneading) may be carried out while heating or cooling depending on the season, environment, etc.

[0087] [Amine curing agent (B)] Examples of the amine curing agent (B) include conventionally known amine compounds used as curing agents for epoxy compounds. The amine curing agent (B) used in the present composition may be one type or two or more types.

[0088] Specific examples of the amine curing agent (B) include water-soluble amine curing agents and water-insoluble amine curing agents, and it is preferable to use a water-insoluble amine curing agent because it allows for the easy formation of a coating film that has excellent low-temperature drying and curing properties. For example, when a water-soluble amine curing agent is used, it may be impossible to determine whether the water-soluble amine curing agent is water-soluble after mixing with other components that may be contained in the second part, but even in such cases, when the water-soluble amine curing agent is used as a raw material in preparing the second part, etc., it is said to include a water-soluble amine curing agent in the present invention. The same applies to water-insoluble amine curing agents.

[0089] The water-soluble amine curing agent in the present invention refers to a component containing an epoxy-curing amine compound that dissolves in a dispersion medium containing water (hereinafter also referred to as an "aqueous medium"). Specifically, the water-soluble amine curing agent refers to a component containing an amine compound that, when 30% by mass of water and 70% by mass of the amine compound that constitutes the amine curing agent are mixed at 25°C and thoroughly stirred, results in a mixture that is transparent in appearance.

[0090] Examples of the water-soluble amine curing agent include water-soluble compounds among the amine compounds used as curing agents for the following epoxy compounds, and compounds obtained by making water-soluble the amine compounds used as curing agents for the following epoxy compounds by a known method. Examples of methods for making the polymer water-soluble include introducing 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, and introducing a hydrophilic group, such as by adduct-modifying a glycidyl ether of a polyalkylene glycol.

[0091] The water-insoluble amine curing agent of the present invention refers to a component containing an epoxy-curing amine compound that is insoluble in an aqueous medium. Specifically, the water-insoluble amine curing agent refers to a component containing an amine compound that, when mixed at 25°C with 30% by mass of water and 70% by mass of the amine compound that constitutes the amine curing agent and thoroughly stirred, results in a mixture that is not transparent but translucent or cloudy in appearance.

[0092] Examples of the water-insoluble amine curing agent include water-insoluble compounds among the amine compounds used as curing agents for the epoxy compounds described below. Other examples include compounds that are emulsified and dispersed in a relatively large amount in an aqueous medium (hereinafter also referred to as "water-dilutable") among the amine compounds used as curing agents for the epoxy compounds described below, water-dilutable components containing hydrophilic amine compounds obtained by reacting the amine compounds used as curing agents for the epoxy compounds described below with glycidyl ethers of polyalkylene glycols or polyoxyalkylene amines, water-dilutable components containing amine compounds having an amide structure obtained by using fatty acids and aliphatic amine compounds, and water-dilutable components obtained by forcibly dispersing in water an amine compound that has been given emulsifying ability by neutralizing the amine compounds used as curing agents for the epoxy compounds described below with an acid or mixing them with an emulsifier.

[0093] The amine compound used as a curing agent for the epoxy compound 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. Examples of such an amine compound include an amine compound containing two or more amino groups in one molecule, and aliphatic, alicyclic, aromatic, and heterocyclic amine compounds are preferred.

[0094] Examples of the aliphatic amine compounds include alkylene polyamines, polyalkylene polyamines, and alkylamino alkyl amines.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] Other aliphatic amine curing agents 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.

[0099] Specific examples of the alicyclic amine curing agent include cyclohexanediamine, diaminodicyclohexylmethane (particularly, 4,4'-methylenebiscyclohexylamine), 4,4'-isopropylidenebiscyclohexylamine, norbornanediamine, and 2,4-di(4-aminocyclohexylmethyl)aniline.

[0100] Examples of the aromatic amine curing agent 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 curing agent 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.

[0101] Specific examples of the heterocyclic amine curing agent include 1,4-diazacycloheptane, 1,4-bis(3-aminopropyl)piperazine, 1-[2'-(2''-aminoethylamino)ethyl]piperazine, 1,11-diazacycloeicosane, and 1,15-diazacyclooctacosane.

[0102] Further examples of the amine compound used as a curing agent for the epoxy compound include modified products of the above-mentioned amine compounds, such as fatty acid modified products such as modified alicyclic polyamines, modified aliphatic polyamines, and polyamidoamines, amine adducts with epoxy compounds, Mannich-modified amines (e.g., Mannich-modified amines having a phenol-derived skeleton (phenalkamine, phenalkamide, etc.)), Michael adducts, ketimines, and aldimines. Among these, modified alicyclic polyamines, modified aliphatic polyamines, polyamidoamines, amine adducts with epoxy compounds, and Mannich-modified amines having a phenol-derived skeleton are preferred.

[0103] The active hydrogen equivalent of the solid content of the amine curing agent (B) is preferably 20 to 200, more preferably 30 to 190, from the viewpoint of being able to easily form a coating film that has excellent low-temperature drying curing properties and corrosion resistance.

[0104] From the viewpoint of easily forming a coating film that is excellent in corrosion resistance, coating film strength, and low-temperature drying and curing properties, it is desirable to use the amine curing agent (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.

[0105] Reactivity ratio = {(amount of solid content of amine curing agent (B) / active hydrogen equivalent of solid content of amine curing agent (B)) + (amount of solid content of component reactive with aqueous epoxy resin (A) / functional group equivalent of solid content of component reactive with aqueous epoxy resin (A))} / {(amount of solid content of aqueous epoxy resin (A) / epoxy equivalent of solid content of aqueous epoxy resin (A)) + (amount of solid content of component reactive with amine curing agent (B) / functional group equivalent of solid content of component reactive with amine curing agent (B))} (3)

[0106] Here, examples of the "component reactive with the amine curing agent (B)" and the "component reactive with the aqueous epoxy resin (A)" in the formula (3) include the silane coupling agent (C). As the silane coupling agent (C), 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 (C) is reactive with the amine curing agent (B) or the aqueous epoxy resin (A), and then calculate the reactivity ratio.

[0107] 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.

[0108] The amount of solids of the amine curing agent (B) in step 2 is preferably an amount that satisfies the above formula (3), and more preferably an amount that falls within the following range, from the viewpoint of easily forming a coating film that is excellent in corrosion resistance and low-temperature drying and curing properties. The amount of the amine curing agent (B) in solid content is preferably 1 to 30 mass %, more preferably 2 to 20 mass %, relative to 100 mass % of the nonvolatile content of the composition. The amount of the solid content of the amine curing agent (B) is preferably 5 to 99 mass %, more preferably 7 to 99 mass %, relative to 100 mass % of the solid content of the second part.

[0109] [Other ingredients] In step 2, if desired, other components than the amine curing agent (B), such as a silane coupling agent (C), water, a flash rust inhibitor, a pigment, a pigment dispersant, an antifoaming agent, a viscosity modifier (anti-sagging agent, anti-settling agent, thixotropic agent), a plasticizer, a curing accelerator, a dehydrating agent, a film-forming aid, a divalent or higher polycarboxylic acid, a curing catalyst, an organic solvent, etc. may be used within the range that does not impair the effects of the present invention (the second agent may contain the other components). These other components may each be used alone or in combination of two or more.

[0110] The other components may be conventionally known components, and examples of the flash rust inhibitor, pigment, dispersant, antifoaming agent, viscosity modifier (anti-sagging agent, anti-settling agent, thixotropic agent, film-forming aid, and organic solvent include the same components as those listed in the section for the first agent. As the other components, commercially available products may be used, and in this case, the commercially available products may be available for both solvent-based and aqueous systems. When water is blended into the second agent to make the second agent an aqueous system, it is preferable to use commercially available products for aqueous systems as the other components used in the second agent, and when an organic solvent is blended into the second agent to make the second agent an organic solvent system, it is preferable to use commercially available products for solvent-based systems as the other components used in the second agent.

[0111] It is preferable to incorporate a flash rust inhibitor into the second agent, as this makes it easier to obtain a composition with better flash rust resistance. In this case, the amount of flash rust inhibitor incorporated is preferably 0.01 to 5 mass %, and more preferably 0.03 to 5 mass %, relative to 100 mass % of the solids content of the second agent.

[0112] Furthermore, it is preferable to incorporate a film-forming aid into the second agent, in order to facilitate the formation of a coating film that has excellent film-forming properties and appearance at low temperatures. In this case, the amount of the film-forming aid incorporated is preferably 0.05 to 50 mass %, more preferably 1 to 35 mass %, relative to 100 mass % of the solids content of the second agent.

[0113] <Process 3> Step 3 is an optional step (performed when the kit is a three- or more-component kit) in which the nth agent is prepared. For example, when the kit is a four-component kit, step 4 is a step in which the third and fourth agents are prepared. Step 3 may be carried out as appropriate depending on the components used in the nth agent, but it is preferable to use the silane coupling agent (C) itself as the nth agent (in this case, step 3 can also be said to be a step using the silane coupling agent (C)). In addition, in step 3, the other components and water described in the sections for step 1 and step 2 may be used together with the silane coupling agent (C), or the other components and water may be used without using the silane coupling agent (C). In step 3, when two or more components are used, the components to be blended may be mixed (or kneaded) in the same manner as in step 1 or step 2 above.

[0114] <Step 4> The step 4 is a step of mixing the first agent prepared in step 1, the second agent prepared in step 2, and, if necessary, the nth agent prepared in step 3. The composition can be produced by mixing (or kneading) the first agent, the second agent, and the optionally used nth agent. During this mixing (or kneading), the agents may be mixed at once or in multiple batches. When the nth agent is used in step 4, the order in which the first agent, second agent, and nth agent are mixed is not particularly limited. The mixing (or 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 (or kneading) can be carried out while heating or cooling depending on the season, environment, etc.

[0115] <Coating film, coated substrate> The coating film of the present invention (hereinafter also referred to as "the coating film") is formed using the kit, and specifically, is formed from the composition obtained from the kit or the composition produced by the method. The present coating film is preferably used as a coated substrate comprising a substrate and the present coating film (hereinafter also referred to as "substrate with the present coating film"). The substrate with the present coating film is a laminate having the present coating film and a substrate.

[0116] 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.

[0117] The substrate is not particularly limited and can be used without any restrictions. However, substrates that require corrosion resistance are preferred in terms of, for example, being able to more effectively utilize the effects of using the present composition, and (steel) structures such as ships, marine structures, plants, bridges, tanks, and containers are more preferred.

[0118] The dry film thickness of the coating film is not particularly limited, but is preferably 10 to 500 μm, more preferably 15 to 400 μm, from the viewpoint that a coating film with excellent corrosion resistance can be easily obtained.

[0119] 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 have 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, a topcoat coating film for the purpose of weather resistance, aesthetics, etc. Specifically, when the present composition is used as a substitute for a zinc primer, an intermediate coating film and a top coating film may be formed on the present coating film. 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. 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, or the present composition may be used alone.

[0120] <Manufacturing method of substrate with coating film> The method for producing a substrate with a coating film according to the present invention includes the following steps I and II. Step I: A step of applying the present composition obtained using the present kit or the present composition produced by the present method to a substrate. Step II: A step of drying the composition applied to the substrate to form the coating film.

[0121] <Process I> The coating method in step I 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 the effects of the present invention to be more effectively exhibited and allows for easy coating of large-area substrates such as the structure.

[0122] 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.

[0123] The coating is preferably carried out so that the dry film thickness of the main coating film formed in step II falls within the above range. In this case, the main coating film of the desired film thickness may be formed by one coating (single coating), or by two or more coatings (two or more coatings). Note that two-coating refers to performing steps I and II, and then performing steps I and II on the coating film obtained in step II.

[0124] 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 film to the substrate. Furthermore, the substrate may be coated with a shop primer or the like for the purpose of primary rust prevention.

[0125] <Process II> The drying conditions in Step II are not particularly limited and may be set appropriately depending on the coating film formation method, the type of substrate, the intended use, the coating environment, etc., but the drying temperature is usually 10 to 35°C in the case of drying at room temperature, and usually 30°C or higher but lower than 100°C, more preferably 40 to 80°C in the case of forced drying using a hot air dryer or the like. Furthermore, since the present composition has excellent low-temperature drying and curing properties, and in order to further demonstrate the effects of the present invention, it is preferable to dry the composition at a low temperature, specifically, 0 to 10° C., preferably 5 to 10° C. The present composition can be sufficiently dried and cured even at such low temperatures. The drying time varies depending on the drying method of the coating film, and is, for example, about 1 to 7 days in the case of low temperature drying or room temperature drying, and about 5 to 60 minutes in the case of forced drying. [Example]

[0126] The present invention will be further described below with reference to examples, but the present invention is not limited to these examples.

[0127] [Examples 1 to 23 and Comparative Examples 1 to 4] The first agent was prepared by placing each component listed in the first agent column of Table 1 or 2 in a container in the amounts (numbers, parts by mass) listed in Table 1 or 2 and stirring using a high-speed disperser at room temperature (23°C) for 30 minutes. In addition, the second agent was prepared by placing each component listed in the second agent column of Table 1 or 2 in a separate container in the amounts (numbers, parts by mass) listed in Table 1 or 2 and stirring using a high-speed disperser until the temperature reached 45-50°C. The prepared first and second agents and, if necessary, the third agent listed in the third agent column of Table 1 or 2 were mixed in the mixing ratio (mass %) listed in Table 1 or 2 to prepare an aqueous coating composition with a total amount listed in Table 1 or 2. A description of each component listed in Tables 1 and 2 is provided in Table 3.

[0128] <Dry curing> Each of the water-based coating compositions was applied to a glass plate of 348 mm x 25 mm x 2 mm (thickness) using a film applicator so that the dry coating thickness would be 150 μm. Using an RC-type drying time recorder (manufactured by Coating Tester Co., Ltd.) at a temperature of 5°C, the test needle of the RC-type drying time recorder was slowly moved over the coating film at a constant speed (a speed that made the measurement time 24 hours), and the state of the coating film was judged from the trace left by the test needle, and the time from immediately after the coating film formation until the coating film was semi-cured (semi-curing time) was determined. The results are shown in Tables 1 and 2. The semi-curing time is specifically as follows:

[0129] FIG. 1 shows a schematic plan view (schematic explanatory diagram) of a glass plate 2 on which a coating film 1 has been formed, viewed from above the coating film 1 side. Position a is the position where the test needle is placed in contact with the coating film 1 formed on the glass plate 2 and starts to move. Position b is the position where the glass plate 2 on which the coating film 1 is formed becomes invisible (because of the coating film 1) when viewed from above the coating film 1 side, and position c is the position where the test needle slides over the surface of the coating film 1 and leaves no trace on the surface of the coating film 1. The time required for the test needle to move from position a to position b was defined as the half-cure time (the time required for the test needle to move from position a to position c was defined as the full-cure time).

[0130] <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. Each of the water-based coating compositions was applied to the surface of this steel plate using an applicator so that the dry film thickness was 100 μm. Immediately after application of each of the water-based coating compositions, the steel sheets were dried at a temperature of 5°C and a relative humidity of 70%RH for 24 hours to form a coating film, and then immersed in water at a temperature of 23±3°C for 3 hours. After immersion in water for 3 hours, the coating film was visually evaluated according to the following evaluation criteria. The results are shown in Tables 1 and 2.

[0131] (Evaluation criteria) 5: No blistering is observed on the coating film on the steel plate 4: Blisters are observed in less than 3% of the total area of ​​the coating on the steel sheet. 3: Blisters are observed in an area that is 3% or more but less than 15% of the total area of ​​the coating on the steel sheet. 2: Blisters are observed on 15% or more but less than 50% of the total area of ​​the coating on the steel sheet. 1: Blisters are observed on more than 50% of the total area of ​​the coating on the steel sheet. 0: The coating on the steel plate peeled off from the steel plate.

[0132] <Impact resistance test> Each of the above water-based coating compositions was applied to a tinplate (150 mm × 70 mm × 0.3 mm (thickness)) using an applicator so that the dry film thickness was 75 μm. The coating was dried for one day at 25°C and a relative humidity of 50% RH, and then dried for 7 days at 50°C to form a coating film on one side (front side) of the tinplate, thereby preparing a test coated plate. The backside (the side without the coating) of each test plate was subjected to a weight drop test according to the DuPont method of JIS K 5600-5-3:1999 (drop height: 200 mm, weight mass: 1000±1 g, weight radius: 1 / 4 inch (6.35 mm)). A cutter blade was inserted between the tinplate and the coating on the front side of each test plate opposite the weight drop point (the side opposite the weight drop point). The cutter blade was moved approximately parallel to the tinplate surface, from the center of the weight drop point outward, as if peeling the coating from the tinplate. Impact resistance was evaluated according to the following evaluation criteria. The results are shown in Tables 1 and 2.

[0133] (Evaluation criteria) ○: The area where the coating peels off is within 1 / 2 inch (12.7 mm) of the center point of the weight's drop. ×: The area where the coating peels off is more than 1 / 2 inch (12.7 mm) from the center point of the weight's drop point.

[0134] [Table 1]

[0135] [Table 2]

[0136] [Table 3] [Explanation of symbols]

[0137] 1: Coating 2: Glass plate 3: Test needle mark a: Test needle movement start position b: The position where the glass plate is no longer visible c: The position where the test needle slides over the coating surface and leaves no trace of the test needle on the coating surface.

Claims

1. a first agent containing an aqueous epoxy resin (A); a second part containing an amine curing agent (B); a multi-component water-based coating composition kit containing a silane coupling agent (C) and water, The content of the solid content of the silane coupling agent (C) in the aqueous coating composition is 0.05 to 0.60 parts by mass per 1 part by mass of water in the aqueous coating composition. Kit for water-based paint composition.

2. 2. The kit for an aqueous coating composition according to claim 1, wherein the content of the solid content of the silane coupling agent (C) in the aqueous coating composition is 0.07 to 1.2 parts by mass per 1 part by mass of the solid content of the aqueous epoxy resin (A) in the aqueous coating composition.

3. 2. The kit for an aqueous coating composition according to claim 1, wherein the content of the solid content of the silane coupling agent (C) in the aqueous coating composition is 0.05 to 0.80 parts by mass per 1 part by mass of the total of the solid content of the aqueous epoxy resin (A) and the solid content of the amine curing agent (B) in the aqueous coating composition.

4. 2. The kit for an aqueous coating composition according to claim 1, wherein the content of the solid content of the silane coupling agent (C) in the aqueous coating composition is 0.03 to 0.25 parts by mass per 1 part by mass of the nonvolatile content of the aqueous coating composition.

5. 2. The kit for an aqueous paint composition according to claim 1, wherein the water content in the aqueous paint composition is 5 to 50 mass %.

6. 2. The kit for an aqueous paint composition according to claim 1, wherein the content of nonvolatile matter in the aqueous paint composition is 40 to 95 mass %.

7. A coating film formed using the kit for a water-based coating composition according to any one of claims 1 to 6.

8. A coated substrate comprising a substrate and the coating film of claim 7.

9. A method for producing a substrate with a coating film, comprising the following steps I and II: Step I: A step of applying to a substrate an aqueous coating composition obtained using the kit for an aqueous coating composition according to any one of claims 1 to 6. Step II: A step of drying the water-based coating composition applied to the substrate to form a coating film

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