Anticorrosion coating composition

Abstract

To provide an anticorrosive coating composition capable of forming a coating layer having excellent adhesiveness to a base material including a galvanized layer as well as to the steel itself, and also exhibiting superior anticorrosiveness for a long time.SOLUTION: An anticorrosive coating composition contains an epoxy resin (A), an amine curing agent (B), an aluminium phosphate compound (C) excluding secondary aluminium phosphate, tertiary aluminium phosphate and aluminum phosphite, and at least one phosphorous compound (D) selected from an aluminum phosphite compound (D1) and a zinc phosphite compound (D2).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an 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] The components (substrates) that make up structures are subjected to various treatments or coated with various coatings in order to impart various functions such as corrosion resistance, stain resistance, weather resistance, scratch resistance, and designability.

[0003] Steel materials are often used as the substrate, and since steel materials are particularly susceptible to rust and corrosion, it is necessary to protect the substrate from rust and corrosion. Known methods for protecting a substrate from such rust and corrosion include forming an anticorrosion coating on the substrate, forming a zinc-plated layer by (hot-dip) galvanizing the substrate, etc. Depending on the type of structure, a zinc-plated substrate on which a zinc-plated layer has been formed may be used as is (without forming any other coating on the zinc-plated layer), but may also be used with an additional anticorrosion coating formed on the zinc-plated layer for the purposes of improving the appearance, extending the service life of the substrate, etc.

[0004] As a composition used to form an anticorrosion coating on such a zinc plating layer, for example, the composition described in Patent Document 1 is known. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-144046 Summary of the Invention [Problem to be solved by the invention]

[0006] Anticorrosion coatings formed on zinc-plated layers tend to have poor adhesion to the zinc-plated layer due to factors such as the fact that the zinc-plated layer is softer than the base material, such as steel, and that white rust (zinc oxide) occurs on the zinc-plated layer.

[0007] Furthermore, since structures that have been built once (e.g., steel towers such as power transmission towers and radio wave towers) cannot be easily rebuilt, repair and maintenance coating is carried out to form a corrosion-resistant coating on the zinc-plated layer in order to repair and maintain the functions (e.g., corrosion resistance) imparted to the base material. In addition to zinc plating layers, the surfaces on which corrosion-resistant coatings are formed during repair and maintenance painting include the surfaces of steel and other substrates where the zinc plating layer has deteriorated or disappeared, or where the surface has become exposed due to surface preparation (priming) performed as a pretreatment for forming corrosion-resistant coatings. Therefore, the corrosion-protective coating formed during such repair and maintenance painting must adhere not only to the zinc plating layer but also to the surface of the substrate, such as steel, but no corrosion-protective coating has been found that has excellent adhesion to either of these surfaces.

[0008] Furthermore, in order to suppress the occurrence of red rust and the like, corrosion-resistant coatings containing zinc, which has an ionization tendency lower than iron and is expected to have a sacrificial corrosion protection effect, are often used on steel materials, but it is thought that even if such corrosion-resistant coatings containing zinc are provided on a zinc-plated layer, they will not exhibit corrosion protection. In other words, the fact that the corrosion protection methods for steel materials and zinc-plated substrates are often different has also limited the use of corrosion-resistant coatings that have been used on zinc-plated layers on the surface of steel materials, etc.

[0009] The present invention has been made in view of the above, and an object of the present invention is to provide an anticorrosion coating composition that has excellent adhesion not only to substrates having a zinc-plated layer but also to steel materials themselves, and that can form an anticorrosion coating film that has excellent corrosion prevention properties over a long period of time. [Means for solving the problem]

[0010] As a result of extensive research into methods for solving the above problems, the inventors have found that the above problems can be solved by a coating composition having a specific composition, and have thus completed the present invention. An example of the configuration of the present invention is as follows.

[0011] <1> an epoxy resin (A); an amine-based curing agent (B); an aluminum phosphate-based compound (C) other than aluminum diphosphate, aluminum triphosphate, and aluminum phosphite; At least one phosphorous compound (D) selected from aluminum phosphite compounds (D1) and zinc phosphite compounds (D2); An anticorrosion coating composition comprising:

[0012] <2> the mass ratio ((D) / (C)) of the phosphorous acid compound (D) to the aluminum phosphate compound (C) is 0.2 to 5.0; <1> The anticorrosion coating composition according to claim 1.

[0013] <3> the total content of the aluminum phosphate compound (C) and the phosphorous acid compound (D) is 1.5 to 35 mass% relative to 100 mass% of the nonvolatile content of the anticorrosive coating composition; <1> or <2> The anticorrosion coating composition according to claim 1.

[0014] <4> The epoxy resin (A) contains an epoxy resin having an alkylphenol structure. <1> ~ <3> 1. The anticorrosion coating composition according to any one of claims 1 to 9.

[0015] <5> The composition further contains an organic solvent, and the organic solvent is an aliphatic hydrocarbon solvent or an aromatic hydrocarbon solvent having a boiling point of 150°C or higher. <1> ~ <4> 1. The anticorrosion coating composition according to any one of claims 1 to 9.

[0016] <6> For zinc-plated substrates, <1> ~ <5> 1. The anticorrosion coating composition according to any one of claims 1 to 9.

[0017] <7> <1> ~ <6> 1. A corrosion-resistant coating film formed from the corrosion-resistant coating composition according to any one of claims 1 to 9. <8> <7> A substrate with a corrosion-resistant coating film, comprising the corrosion-resistant coating film according to claim 1 and a substrate.

[0018] <9> A method for producing a substrate with a corrosion-resistant coating, comprising the following steps [1] and [2]: [1] <1> ~ <6> a step of applying the anticorrosion coating composition according to any one of the preceding claims to a substrate. [2] A step of drying the applied anticorrosion coating composition to form an anticorrosion coating film. [Effects of the Invention]

[0019] The anticorrosion coating composition of the present invention has excellent adhesion not only to substrates having a zinc-plated layer but also to steel materials themselves, and can form an anticorrosion coating film that has excellent corrosion resistance over a long period of time. Therefore, the anticorrosion coating composition of the present invention can be suitably used not only for newly constructed steel substrates or substrates having a zinc-plated layer (it can form an anticorrosion coating film that has excellent adhesion and corrosion resistance), but also for repair and maintenance coating of structures that are already in use. Furthermore, the anticorrosion coating composition of the present invention can be a composition that can be cured at room temperature and has excellent drying properties, and can provide a composition that is less likely to splash off a brush or the like when applied with a brush.

[0020] In addition, structures that have been formed once (e.g., steel towers such as power transmission towers and radio wave towers) may have not only a zinc plating layer but also a functional film such as a corrosion-resistant coating (hereinafter also referred to as the "old coating film") formed thereon. As mentioned above, once a structure is formed, it cannot be easily rebuilt. Therefore, repair and maintenance painting is sometimes carried out to form an anticorrosion coating film on the old paint film in order to repair or maintain the functions (e.g., corrosion resistance) imparted to the substrate. The anticorrosion coating film formed during such repair and maintenance painting is also required to have good adhesion to the old paint film. The anticorrosion coating composition of the present invention can form an anticorrosion coating film that has excellent adhesion to such old paint films. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic plan view of a test plate with a notch formed thereon, used in the corrosion resistance test in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0022] <Anti-corrosion coating composition> The anticorrosion coating composition according to one embodiment of the present invention (hereinafter also simply referred to as "the composition") comprises: An epoxy resin (A) [hereinafter also referred to as "component (A)"; the same applies to other components], an amine-based curing agent (B); an aluminum phosphate-based compound (C) other than aluminum diphosphate, aluminum triphosphate, and aluminum phosphite; At least one phosphorous compound (D) selected from aluminum phosphite compounds (D1) and zinc phosphite compounds (D2); Contains:

[0023] Because the present composition exhibits the above-mentioned effects, it can be suitably used as an undercoat paint where adhesion to substrates (particularly substrates having a zinc plating layer) and corrosion protection of the substrate are required, and as a topcoat paint for old coating films where adhesion to the old coating film is required (an intermediate coating paint where the old coating film serves as the undercoat paint film). Furthermore, the present composition can be suitably used to form a corrosion-protective coating on a newly constructed substrate (steel itself or a zinc-plated substrate), and can also be suitably used for repair and maintenance coating of structures that are already in use (substrates with exposed steel, substrates with old paint films (including deteriorated old paint films), or substrates with zinc-plated layers (including deteriorated zinc-plated layers)).

[0024] The present composition can be used without limitation in applications requiring the effects of the present composition, but specifically, for example, it is used in structures such as plant structures, onshore structures, offshore structures, ships, etc. (including substrates used in newly constructing these structures and substrates that constitute these structures; the same applies hereinafter). Among these, it is preferable to use it in onshore (large) structures such as steel towers (e.g., power transmission towers, radio towers) and bridges, and it is particularly preferable to use it in steel towers, because the effects of using the present composition can be more effectively exhibited. Furthermore, since the present composition can form a corrosion-resistant coating film that is excellent in adhesion and corrosion prevention properties on steel materials, zinc-plated layers, and old paint films, this effect is more pronounced, and therefore it is preferably used for steel materials, zinc-plated substrates, and substrates having old paint films; and since the present composition can form a corrosion-resistant coating film that is excellent in adhesion and corrosion prevention properties, particularly on zinc-plated layers, this effect is more pronounced, and therefore it is more preferably used for zinc-plated substrates.

[0025] As mentioned above, the present composition is preferably used for land-based (large) structures such as steel towers. The present composition to be applied to such structures is preferably a weak solvent-based paint composition (weak solvent paint composition). Such weak solvent-based paint compositions are preferred in that they have less odor than strong solvent-based paint compositions containing aromatic solvents such as toluene and xylene, and can reduce the burden on painters and the environment. Furthermore, the present composition may be applied over an old paint film. In this case, the composition is unlikely to corrode (dissolve) the old paint film, and a corrosion-resistant coating film can be formed on top of the old paint film while maintaining the functionality of the old paint film. Therefore, when the present composition is applied over an old paint film in this way, it is preferable that the present composition be a weak-solvent paint composition.

[0026] When the present composition is used, particularly for repair and maintenance painting as described above, painting is often carried out at the site where the structure is installed, and in this case, it is necessary to prevent the composition from scattering to areas other than the painted area, so painting is usually carried out using a brush, roller, spatula, trowel, etc. (also referred to as a "brush, etc." in this specification). Therefore, the present composition is preferably a composition for painting using a brush, etc., and particularly a composition for brush application.

[0027] When the present composition is applied using a brush or the like, particularly when the present composition is used on a steel tower, the viscosity of the present composition is preferably 1 to 5 Pa·s, more preferably 1.5 to 5 Pa·s. When applying with a brush or the like, if the viscosity of the present composition is within the above range, it is possible to easily obtain a composition that is less likely to scatter from the brush or the like. The viscosity can be measured using a B-type viscometer (model: BII-type viscometer, manufactured by Toki Sangyo Co., Ltd.) at a temperature of 25° C. and a rotation speed of 60 rpm using a No. 4 rotor.

[0028] 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 base component and a curing agent component, and is preferably a two-component composition containing, for example, a base component containing component (A), preferably a base component containing components (A), (C), and (D), and a curing agent component containing component (B). The composition may also be a three-component or higher composition further containing a third component containing additives, etc., as described below. These main agent component, hardener component, third agent, etc. are usually stored, preserved, transported, etc. in separate containers, and are mixed immediately before use.

[0029] <Epoxy resin (A)> Component (A) is not particularly limited, and any conventionally known epoxy resin can be used. Component (A) is preferably a resin (including polymers and oligomers) having two or more epoxy groups in one molecule. The component (A) used in the present composition may be one type or two or more types.

[0030] Examples of component (A) include glycidyl ether-type epoxy resins; glycidyl ester-type epoxy resins; alicyclic epoxy resins; modified epoxy resins obtained by modifying these epoxy resins with at least one selected from alkylphenols and fatty acids; alkylphenyl glycidyl ethers (e.g., reaction products of alkylphenols and epichlorohydrin); and alkylphenol novolac-type epoxy resins (e.g., reaction products of novolac-type alkylphenol resins and epichlorohydrin).

[0031] Examples of the glycidyl ether type epoxy resin include epoxy resins having a glycidyl ether group obtained by reacting a hydroxyl group-containing compound such as a polyhydric alcohol or a polyhydric phenol with an epoxy group-containing compound such as epichlorohydrin. Specific examples of the polyhydric alcohol include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, neopentyl glycol, 1,2-butanediol, 1,4-butanediol, 1,6-hexanediol, glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, and sorbitol. Specific examples of the polyhydric phenol include 2,2-bis(4-hydroxyphenyl)propane [bisphenol A], 2,2-bis(2-hydroxyphenyl)propane, 2-(2-hydroxyphenyl)2-(4-hydroxyphenyl)propane, halogenated bisphenol A, bis(4-hydroxyphenyl)methane [bisphenol F], tris(4-hydroxyphenyl)propane, resorcinol, tetrahydroxyphenylethane, novolac-type polyhydric phenols, and cresol-type polyhydric phenols.

[0032] Examples of the glycidyl ester type epoxy resin include phthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, and dimer acid diglycidyl ester.

[0033] Examples of the alicyclic epoxy resin include 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3',4'-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, and bis(3,4-epoxycyclohexylmethyl)adipate.

[0034] The alkylphenol is preferably a phenol having an alkyl group having 2 to 18 carbon atoms, and specific examples include 4-t-butylphenol, 4-t-pentylphenol, 4-neopentylphenol, 4-octylphenol, and 4-nonylphenol.

[0035] The fatty acids are preferably drying oil fatty acids, semi-drying oil fatty acids, etc., and specific examples include linseed oil fatty acids, safflower oil fatty acids, soybean oil fatty acids, sesame oil fatty acids, perilla oil fatty acids, tung oil fatty acids, corn oil fatty acids, sunflower oil fatty acids, cottonseed oil fatty acids, fish oil fatty acids, tall oil fatty acids, dehydrated castor oil fatty acids, and hygienic fatty acids.

[0036] The method for modifying the epoxy resin using the alkylphenol or fatty acid as a modifier is not particularly limited, and can be carried out by a conventionally known method. The modifier may be used alone or in combination of two or more kinds.

[0037] Component (A) is preferably an epoxy resin having an alkylphenol structure, as it has excellent adhesion to substrates and can easily form a tough anticorrosive coating film. Furthermore, since epoxy resins having an alkylphenol structure are easily soluble in weak solvents, which will be described later, the use of such resins makes it easy to turn the present composition into a weak solvent coating composition.

[0038] Specific examples of the epoxy resin having an alkylphenol structure include alkylphenol-modified epoxy resin, alkylphenyl glycidyl ether, and alkylphenol novolac-type epoxy resin. Among these, alkylphenol-modified bisphenol A epoxy resin and alkylphenol novolac-type epoxy resin are preferred.

[0039] The solid content of component (A) in the present composition is preferably 10 to 45 mass%, more preferably 15 to 35 mass%, based on 100 mass% of the nonvolatile content of the present composition, from the viewpoint of easily forming a corrosion-protective coating film that is resistant to cracking even when formed into a thick film and has a good balance of corrosion protection, flexibility, and adhesion to the substrate. The content of the solid content of component (A) relative to 100% by mass of the solid content of the resin in the present composition is preferably 60 to 98% by mass, and more preferably 65 to 98% by mass.

[0040] 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 in accordance with JIS K 5601-1-2 by weighing 1±0.1 g of the composition (e.g., the composition immediately after mixing the base component and curing agent component) onto a flat-bottomed dish, spreading it evenly using a wire of known mass, drying it at 23°C for 24 hours, and then heating it at 110°C for 1 hour (at normal pressure), and measuring the mass of the wire and the heating residue. 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 additives described below are referred to as "solid content." The nonvolatile content is equivalent to the total amount of solids in the raw material components used in the present composition.

[0041] <Amine-based curing agent (B)> Component (B) is not particularly limited as long as it is an amine compound that serves as a curing agent for component (A), and any conventionally known amine compound can be used. The component (B) used in the present composition may be one type or two or more types.

[0042] Suitable examples of component (B), which are easily soluble in weak solvents as described below and make it easy to turn the composition into a weak-solvent coating composition, include aliphatic polyamines such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine; aromatic polyamines such as metaxylylenediamine, diaminodiphenylmethane, and phenylenediamine; alicyclic polyamines such as 1,3-bis(aminomethyl)cyclohexane and isophoronediamine; and modified polyamines obtained by subjecting these polyamines to modification reactions such as polyamidation, epoxy adduct formation, Mannich formation, ketiminization, and alkylphenolization by known methods.

[0043] Among the above, component (B) is preferably an aliphatic polyamine selected from ethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine, metaxylylenediamine, isophoronediamine, or a modified product of these amines (modified polyamine), and more preferably triethylenetetramine, metaxylylenediamine, or a modified product of these amines (modified polyamine). Component (B) is preferably a component having an alkylphenol structure, as this facilitates the preparation of the composition as a weak solvent coating composition. Examples of components having an alkylphenol structure include components containing alkylphenol-modified polyamines and components containing polyamines and alkylphenols.

[0044] The content of the solid content of component (B) in the present composition is an amount such that the reaction ratio calculated by the following formula (1) is preferably 0.3 to 1.0, more preferably 0.4 to 0.9, in order to obtain a composition with excellent drying properties and to easily form a corrosion-protective coating film that is well-balanced between corrosion protection and adhesion to the substrate. 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)) (1)

[0045] Here, examples of the "component reactive with component (B)" and the "component reactive with component (A)" in the formula (1) include the silane coupling agents described below. 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. 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.

[0046] <Aluminum phosphate compounds (C)> Component (C) is not particularly limited as long as it is an aluminum phosphate-based compound other than aluminum diphosphate (Al2(HPO4)3), aluminum triphosphate (AlPO4) (also known as aluminum orthophosphate), and aluminum phosphite (Al2(HPO3)), and any conventionally known aluminum phosphate-based compound can be used. The component (C) used in the present composition may be one type or two or more types.

[0047] Specific examples of component (C) include monoaluminum phosphate (Al(H2PO4)3), aluminum dihydrogen triphosphate (AlH2PO 10), and aluminum metaphosphate (Al(PO3)3). Furthermore, as component (C), compounds obtained by treating or modifying these compounds with calcium (compound), magnesium (compound), etc. can also be used. Among these, aluminum dihydrogen tripolyphosphate is preferred as component (C) because it is easily dispersed during the production of the present composition and can easily form an anticorrosion coating film with excellent corrosion resistance on a zinc-plated substrate in an outdoor exposure environment.

[0048] The content of component (C) in the present composition is preferably 0.5 to 15 mass %, more preferably 0.8 to 13 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 a good balance between corrosion protection and adhesion to the substrate.

[0049] <Phosphite compounds (D)> Component (D) is at least one compound selected from aluminum phosphite (Al2(HPO3))-based compounds (D1) and zinc phosphite (ZnHPO3)-based compounds (D2). Among these, aluminum phosphite-based compounds (D1) are preferred from the standpoint of availability and other factors. When component (D1) is used in the present composition, the component (D1) may be one type or two or more types, and when component (D2) is used in the present composition, the component (D2) may be one type or two or more types.

[0050] Component (D1) specifically includes aluminum phosphite (Al2(HPO3)), and component (D2) specifically includes zinc phosphite (ZnHPO3). In addition, components (D1) and (D2) can each be compounds obtained by treating or modifying the above compounds with calcium (compound), magnesium (compound), or the like.

[0051] The content of component (D) in the present composition is preferably 0.5 to 25 mass %, more preferably 1 to 20 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 an excellent balance between corrosion protection and adhesion to the substrate.

[0052] The total content of components (C) and (D) is preferably 1.5 to 35 mass%, more preferably 1.5 to 33 mass%, and particularly preferably 2 to 31 mass%, relative to 100 mass% of the nonvolatile content of the composition, in order to easily form a corrosion-protective coating film that has a good balance between corrosion protection and adhesion to the substrate.

[0053] The mass ratio of component (D) to component (C) ((D) / (C)) is preferably 0.2 to 5.0, more preferably 0.2 to 4.8, and particularly preferably 0.2 to 4.6, from the viewpoint of easily forming an anticorrosion coating film that has a good balance of anticorrosion properties and adhesion to the substrate, particularly to a substrate having a zinc plating layer.

[0054] <Additives> In addition to the components (A) to (D), the present composition may contain, as necessary, additives such as organic solvents, pigments other than components (C) and (D), silane coupling agents, reactive diluents, anti-sagging agents (anti-settling agents), antifoaming agents, curing accelerators, dispersants, leveling agents, thickeners, and flexibility-imparting agents, provided that the effects of the present invention are not impaired. These additives may be used alone or in combination of two or more. When the present composition is a multi-component composition, these additives may be blended into each component in consideration of their reactivity, and may be blended into the main component or the curing agent component.

[0055] [Organic solvents] The organic solvent is not particularly limited, and conventionally known organic solvents can be used, but it is preferable to select the organic solvent taking into consideration the solubility in the components (A) and (B) used, and specifically, a weak solvent or a strong solvent can be used depending on the components (A) and (B) used. When a weak solvent is used, a solvent other than the weak solvent may be used if necessary, and when a strong solvent is used, a solvent other than the strong solvent may be used if necessary.

[0056] Examples of the weak solvent include hydrocarbon organic solvents such as aliphatic solvents, naphthenic solvents, and aromatic naphtha. Among these, suitable weak solvents that have a particularly low odor and have little adverse effect on the environment include organic solvents with a boiling point of 150°C or higher, and aliphatic hydrocarbon solvents or aromatic hydrocarbon solvents with a boiling point of 150°C or higher are preferred.

[0057] Specific examples of aliphatic hydrocarbon solvents having a boiling point of 150°C or higher include aliphatic hydrocarbon solvents with low dissolving power and little odor, such as mineral spirits, mineral turpentine, white spirits, isoparaffin, IP Solvent 1620, IP Solvent 2028, and IP Solvent 2835 (all manufactured by Idemitsu Kosan Co., Ltd.), n-nonane, isononane, n-decane, and n-dodecane. These aliphatic hydrocarbon solvents may be used alone or in combination of two or more.

[0058] Specific examples of aromatic hydrocarbon solvents having a boiling point of 150°C or higher include solvent naphtha; T-SOL 100, T-SOL 150 (all manufactured by TonenGeneral Sekiyu K.K.); Solvesso 200 (manufactured by ExxonMobil Corporation); Ipzol 100, Ipzol 150 (all manufactured by Idemitsu Kosan Co., Ltd.); Swazol 1000, Swazol 1500, Swazol 1800 (all manufactured by Cosmo Oil Co., Ltd.). These aromatic hydrocarbon solvents may be used alone or in combination of two or more.

[0059] Examples of the strong solvent include aromatic hydrocarbon solvents with a boiling point of less than 150°C, such as toluene and xylene, ester solvents, such as butyl acetate and propylene glycol monomethyl ether acetate, ketone solvents, such as methyl isobutyl ketone, and alcohol solvents, such as n-butanol and propylene glycol monomethyl ether.

[0060] It is preferable to use a weak solvent as the organic solvent because it has less odor than a strong solvent, puts less strain on painting workers and the environment, and when the present composition is applied over an old paint film, it is less likely to erode (dissolve) the old paint film, allowing a corrosion-resistant coating film to be formed from the present composition on top of the old paint film while maintaining its functionality. In this case, the content of the strong solvent relative to all organic solvents in the present composition is preferably less than 5 mass%, and it is more preferable that the present composition does not contain a strong solvent.

[0061] The content of the organic solvent in the composition may be appropriately selected depending on the viscosity of the composition required for the method of applying the composition (e.g., spray coating, application with a brush, etc.). For example, when the present composition is applied using a brush or the like, it is preferable to use an organic solvent so that the viscosity of the present composition falls within the above-mentioned range. Specifically, the content of the organic solvent in the present composition is preferably 5 to 50 mass %, more preferably 10 to 40 mass %.

[0062] [Other pigments] Examples of the other pigments include extender pigments, color pigments, and rust-preventive pigments other than components (C) and (D), and they may be either organic or inorganic. One type of other pigment may be used, or two or more types may be used. When the present composition is a multi-component composition containing a main component and a curing agent component, the other pigment may be blended into either the main component or the curing agent component, or may be blended into both, but it is preferable to blend it into the main component.

[0063] The content of other pigments in the present composition is preferably 20 to 75 mass %, more preferably 25 to 70 mass %, relative to 100 mass % of the nonvolatile content of the present composition, from the viewpoints that the composition has excellent corrosion resistance and also provides a stress relief effect in the coating film formed, thereby facilitating the formation of a corrosion-resistant coating film that has excellent adhesion to substrates, particularly substrates having a zinc plating layer or a substrate having an old coating film.

[0064] The pigment volume concentration (PVC) in the present composition is preferably 10 to 70%, more preferably 20 to 60%, and particularly preferably 25 to 55%, from the viewpoints of being able to easily form a corrosion-resistant coating film that has excellent corrosion resistance and flexibility and excellent adhesion to substrates, particularly substrates having a zinc plating layer or a substrate having an old coating film. When the present composition is applied using a brush or the like, if the PVC of the present composition is within the above range, it is possible to easily obtain a composition that is less likely to scatter from the brush or the like. If the PVC is below the above range, the corrosion prevention properties of the resulting corrosion-protective coating film tend to decrease and the stress relaxation effect tends to be poor. Conversely, if the PVC exceeds the above range, the corrosion prevention properties of the resulting corrosion-protective coating film tend to decrease and the viscosity of the composition tends to increase, which tends to limit the application method (making it unsuitable for spray application).

[0065] The PVC refers to the total volume concentration of pigments (component (C), component (D), and other pigments) relative to the volume of nonvolatile matter in the composition. Specifically, the PVC can be calculated using the following formula: PVC [%] = Total volume of all pigments in the composition × 100 / Volume of non-volatile matter in the composition

[0066] The volume of the nonvolatile content in 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.

[0067] The extender pigment is not particularly limited, and any conventionally known pigment can be used, except for the color pigments and other anti-rust pigments described below. Examples of the extender pigment include talc, mica, barium sulfate (including precipitated barium sulfate and elutriated barium sulfate), (potassium) feldspar, kaolin, alumina white, clay, magnesium carbonate, barium carbonate, calcium carbonate, dolomite, silica, glass flakes, and plastic flakes. Talc, silica, (precipitated) barium sulfate, (potassium) feldspar, and mica are particularly preferred.

[0068] When the present composition contains a body pigment, the content thereof is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, relative to 100% by mass of the nonvolatile content of the present composition, from the viewpoint of easily forming a coating film that is excellent in terms of corrosion prevention, flexibility, and adhesion to substrates, particularly substrates having a zinc plating layer or a substrate having a previous coating film, in a well-balanced manner.

[0069] The color pigment is not particularly limited, and any conventionally known pigment can be used, provided that it is a pigment other than the other rust-preventive pigments described below. Examples of the color pigment include conventionally known inorganic pigments such as carbon black, titanium dioxide (titanium white), iron oxide (red iron oxide), yellow iron oxide, ultramarine, aluminum flakes, scaly iron oxide, and stainless steel flakes, and organic pigments such as cyanine blue and cyanine green. Titanium white, carbon black, and red iron oxide are particularly preferred.

[0070] When the present composition contains a color pigment, the content thereof is preferably 0.1 to 60% by mass, and more preferably 1 to 50% by mass, relative to 100% by mass of the nonvolatile content of the present composition.

[0071] The other rust-preventive pigment is not particularly limited, and any conventionally known pigment can be used, provided that it is a pigment other than components (C) and (D). Examples of the other rust-preventive pigments include metal cyanamide compounds such as zinc cyanamide compounds, zinc phosphate compounds, calcium phosphate compounds, molybdenum phosphate compounds, magnesium phosphate compounds, strontium phosphate compounds, calcium phosphite compounds, and strontium phosphite compounds.

[0072] When the present composition contains such other anti-rust pigments, the content thereof is preferably 1 to 25 mass %, more preferably 5 to 20 mass %, relative to 100 mass % of the non-volatile content of the present composition, from the viewpoint of easily forming an anti-corrosion coating film with superior corrosion prevention properties, etc.

[0073] [Silane coupling agents] The present composition may contain a silane coupling agent, and preferably contains a silane coupling agent. The silane coupling agent is not particularly limited, and conventionally known compounds can be used. However, it is preferable that the silane coupling agent is a compound having at least two functional groups in the same molecule, which can contribute to improving the adhesion to the substrate and reducing the viscosity of the composition. For example, a silane coupling agent having the formula: "X-SiMe n Y 3-n " [n is 0 or 1, X is a reactive group capable of reacting with an organic substance (e.g., amino group, vinyl group, epoxy group, mercapto group, halogen group, group in which a hydrocarbon group is partially substituted with any of these groups, or group in which a hydrocarbon group is partially substituted with an ether bond or the like and is partially substituted with any of these groups), Me is a methyl group, and Y is a hydrolyzable group (e.g., alkoxy group such as methoxy group or ethoxy group).] is more preferable.

[0074] As the silane coupling agent, a compound having an epoxy group and an alkoxy group is preferred, and an alkoxy group-containing silane coupling agent having one epoxy group per molecule is more preferred, because it has excellent adhesion to the substrate and can easily form an anticorrosion coating film with excellent corrosion resistance.

[0075] As the silane coupling agent, commercially available products may be used. Specific examples of such commercially available products include (3,4-epoxycyclohexyl)ethyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM 303", etc.), γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM-403", etc.), γ-glycidoxypropylmethyldimethoxysilane (manufactured by Dow Corning Toray Co., Ltd., "AY43-026", etc.), and γ-glycidoxypropylmethyldiethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE 402", etc.).

[0076] When the present composition contains a silane coupling agent, the content thereof is preferably 0.3 to 5 mass %, more preferably 0.5 to 2.5 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 with superior adhesion to the substrate and superior corrosion protection properties.

[0077] [Anti-sagging agent] As the anti-sagging agent, conventionally known anti-sagging agents such as organoclay waxes such as stearate salts of Al, Ca, and Zn, lecithin salts, and alkylsulfonates, polyethylene wax, amide wax, hydrogenated castor oil wax, synthetic finely powdered silica, and oxidized polyethylene wax can be used. Of these, amide wax, synthetic finely powdered silica, oxidized polyethylene wax, and organoclay wax are preferred.

[0078] When the present composition is a multi-component composition containing a main component and a curing agent component and contains an anti-sagging agent, the anti-sagging agent is preferably blended into the main component. When the present composition contains an anti-sagging agent, the content thereof is preferably 0.1 to 10% by mass.

[0079] [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 down bubbles that have generated in the composition, thereby making it possible to easily form a corrosion-protective coating film with the desired physical properties. As the defoaming agent, various known defoaming agents such as polymer-based, acrylic-based, silicone-based, mineral oil-based, and olefin-based defoaming agents can be used, and among these, polymer-based and olefin-based defoaming agents are preferred.

[0080] The defoaming agent may be a commercially available product, such as "BYK-392," "BYK-066N," or "BYK-1790" (all manufactured by BYK Japan K.K.), "TEGO Airex 902W" (manufactured by EVONIK Industries), "SURFYNOL SE-F" (manufactured by EVONIK Industries), "Spectrasyn 40" (manufactured by Exxonmobil Chemical Company), or "Florene AC-300" (manufactured by Kyoeisha Chemical Co., Ltd.).

[0081] When the present composition contains an antifoaming agent, the solid content thereof 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.

[0082] [Curing accelerator] Examples of the curing accelerator include tertiary amines and polymerizable (meth)acrylate monomers. Specific examples of the tertiary amine include triethanolamine, dialkylaminoethanol, triethylenediamine (1,4-diazabicyclo[2.2.2]octane), and 2,4,6-tris(dimethylaminomethyl)phenol, and commercially available products include "Ancamine K-54" (manufactured by Evonik, 2,4,6-tri(dimethylaminomethyl)phenol).

[0083] Commercially available polymerizable (meth)acrylate monomers include "M-CURE 100," "M-CURE 200," "M-CURE 201," "M-CURE 300," and "M-CURE 400" (all manufactured by SARTOMER COMPANY, INC.).

[0084] When the present composition contains a curing accelerator, the solid content thereof is preferably 0.01 to 5 mass% relative to 100 mass% of the solid content of the present composition, from the viewpoint of easily forming a corrosion-protective coating film that has excellent curability and adhesion to the substrate.

[0085] <Method for preparing the present composition> The present composition can be prepared by mixing (kneading) the above-mentioned components. During this mixing (kneading), the components may be added and mixed all at once, or may be added and mixed in several batches. Also, the mixing may be performed while heating or cooling depending on the season, environment, etc. For the mixing (kneading), a conventionally known mixer, disperser, stirrer, etc. can be used, and examples thereof include a mixing / dispersing mill, a mortar mixer, a roll, a paint shaker, and a homogenizer.

[0086] <Anti-corrosion coating, substrate with anti-corrosion coating> The anticorrosion coating film according to one embodiment of the present invention (hereinafter also referred to as "the present coating film") is a corrosion-resistant coating film formed using the present composition, and the substrate with the anticorrosion coating film according to one embodiment of the present composition (hereinafter also referred to as "the substrate with the present coating film") is a laminate including the present coating film and a substrate (substrate to be coated).

[0087] The substrate is not particularly limited, and can be used without limitation on substrates that require the effects of the present composition. Specific examples include plant structures, land structures, marine structures, ships, and other structures. Among these, land (large) structures such as steel towers (e.g., power transmission towers and radio wave towers) and bridges are preferred, with steel towers being more preferred, in that the effects of using the present composition can be more effectively exhibited. The material of the substrate is not particularly limited, but examples thereof include steel (iron, steel, ferroalloy, carbon steel, mild steel, alloy steel, etc.), aluminum, copper, brass, and stainless steel (SUS304, SUS410, etc.), with steel being preferred.

[0088] The substrate may be a substrate whose surface is plated, zinc sprayed, painted, or the like. The substrate is preferably a steel tower or the like. The substrates used when constructing a new steel tower or the like and the substrates constituting the steel tower or the like are usually steel substrates on which a zinc-plated (particularly hot-dip galvanized) layer is formed. Therefore, the substrate is preferably steel or a substrate on which a zinc-plated layer is formed on the surface thereof. The surface of the substrate may be coated with an old paint film, specifically an old paint film formed from a coating composition such as an alkyd resin, acrylic resin, epoxy resin, epoxy ester resin, or urethane resin. The present composition has excellent adhesion not only to these substrates, particularly to substrates having an old paint film or a zinc-plated layer, but also to steel materials themselves, and therefore, by using these substrates, the effects of the present invention can be more effectively exhibited, and is therefore preferred.

[0089] The dry film thickness of the present coating film is not particularly limited, but is usually 40 to 300 μm, preferably 50 to 270 μm, and more preferably 60 to 240 μm, from the viewpoint of being able to form a present coating film that has sufficient corrosion protection and is well-balanced in terms of adhesion to the substrate.

[0090] The substrate with the present coating film may be a laminate comprising the present coating film and a substrate, and a topcoat coating film having excellent weather resistance and aesthetic appearance may be further formed on the present coating film. Examples of such topcoat coating films include coating films formed from various topcoat paint compositions such as acrylic resin-based, acrylic silicone resin-based, urethane resin-based, silicone resin-based, and fluororesin-based topcoat paint compositions. When the present coating film is formed on a substrate (particularly steel) on which no zinc plating layer or coating film has been formed, or on a substrate having a zinc plating layer, the present coating film acts as an undercoat coating film, on which a topcoat coating film (if necessary via an intermediate coating film) is usually formed; when the present coating film is formed on a substrate having an old coating film, the present coating film acts as an intermediate coating film with the old coating film as the undercoat coating film, on which a topcoat coating film is usually formed.

[0091] <Manufacturing method for substrate with anticorrosion coating> A method for producing a substrate with a corrosion-protective coating according to one embodiment of the present invention (hereinafter also referred to as "the method") 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 applied composition to form the coating film.

[0092] <Process [1]> The coating method in 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, and coating using a brush, and the like. Coating may be automated or manual. Among these, when painting is carried out at a site where a structure is installed, it is necessary to prevent the composition from scattering to areas other than the painted area. In cases where work at height is required, such as when a steel tower is used as the substrate, and paint scattering is a problem, painting with a brush or the like is preferred, with brush painting and roller painting being more preferred, and brush painting being particularly preferred, as it is possible to further prevent the composition from scattering.

[0093] When applying the present composition, the viscosity of the present composition may be adjusted to an appropriate value as desired. In this case, it is preferable to adjust the viscosity of the present composition so that it falls within the above-mentioned range.

[0094] When applying the present composition, a coating film of the desired thickness may be formed in one coat; however, when applying with a brush or the like, it is usually difficult to form a coating film of the above dry thickness in one coat, so it is preferable to apply the composition two or more times (two or more coats) to form a coating film of the desired thickness. Here, "single coating" refers to a method of forming a dry coating film on a substrate through the steps [1] and [2], and after the step of forming a dry coating film, the step [1] is not performed on the dry coating film obtained in that step. "Two or more coatings" refers to a method of performing the step of forming a dry coating film on a substrate through the steps [1] and [2] at least once, and then further performing the steps [1] and [2] on the dry coating film obtained in that step to form a dry coating film.

[0095] When the present composition is used for repair and maintenance coating of a substrate, depending on the substrate, it is preferable to carry out a surface pretreatment process, such as a cleaning process or a blasting process to remove rust, dirt, paint (old paint film), etc. adhering to the substrate, before the step [1]. 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.

[0096] <Process [2]> The drying conditions in step [2] are not particularly limited and may be set appropriately depending on the coating method, type of substrate, application, coating environment, etc., but the drying temperature, when drying at room temperature, is usually 5 to 35°C, more preferably 10 to 30°C. Although forced drying (e.g., 30 to 90°C) may be performed by heating or air blowing if desired, drying under natural conditions (room temperature drying) is usually performed, and room temperature drying is usually used, particularly when coating is performed at a site where a structure is installed. The drying time varies depending on the drying temperature, but in the case of drying at room temperature, it is usually 1 to 7 days, preferably 1 to 3 days. [Example]

[0097] The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0098] [Example 1] The components that make up the main component shown in Table 1 were placed in a plastic container in the amounts (numbers, parts by mass) shown in Table 1, and after stirring using a high-speed disperser, an appropriate amount of glass beads were added and dispersed using a paint shaker for 1 to 2 hours. The glass beads were then removed to prepare the main component. Furthermore, each component constituting the curing agent component shown in Table 1 was added to a container in the amount (number, parts by mass) shown in Table 1, and the curing agent component was prepared by thoroughly dispersing the components using a high-speed disperser. When coating, the main component and the curing agent component were mixed to prepare an anticorrosion coating composition.

[0099] [Examples 2 to 14 and Comparative Examples 1 to 11] The main component, the curing agent component and the anticorrosion coating composition were prepared in the same manner as in Example 1, except that the types and blending amounts of each component constituting the main component and the curing agent component were changed as shown in Tables 1 and 2 below. The components listed in Tables 1 and 2 are explained in Table 3.

[0100] <Preparation of test plate> The anticorrosion coating composition prepared in each Example and Comparative Example was applied to any of the following substrates 1 to 3 (on the polished surface for Substrate 1 and on the topcoat for Substrate 2) to an average dry film thickness of 60 μm, and dried at room temperature (23°C) for one day to form a first anticorrosion coating film. Subsequently, the same coating composition as used for the first layer was applied to the formed first anticorrosion coating film to an average dry film thickness of 60 μm, and dried at room temperature for one day to form a second anticorrosion coating film. Furthermore, the same coating composition as used for the first layer was applied to the formed second anticorrosion coating film to an average dry film thickness of 60 μm, and dried at room temperature for one day to form a third anticorrosion coating film. Next, "Flolex Top Coat MS HB" (a weak solvent fluororesin-based top coat paint manufactured by Chugoku Paint Co., Ltd.) was applied to the third layer of corrosion protection coating so that the average dry film thickness was 55 μm, and the coating was dried at room temperature for 7 days to prepare a test panel. Substrate 1: Hot-dip galvanized steel plate (dimensions: 150 mm x 70 mm x 3.0 mm (thickness)) polished with #240 sandpaper Substrate 2: A hot-dip galvanized steel plate (dimensions: 150 mm x 70 mm x 3.0 mm (thickness)) on which Galvanite No. 400 Primer (manufactured by Chugoku Toryo Co., Ltd., an epoxy resin-based primer for newly installed zinc-plated surfaces) was applied to an average dry film thickness of 40 μm, and then dried at room temperature for one day to form an undercoat film. Next, Unimarine HS (manufactured by Chugoku Toryo Co., Ltd., a polyurethane resin-based topcoat) was applied to the undercoat film to an average dry film thickness of 50 μm, and then dried at room temperature for seven days to form a topcoat film. Base material 3: Sandblasted steel plate (dimensions: 150mm x 70mm x 2.3mm (thickness))

[0101] <Corrosion resistance> A cross-line notch (see JIS K 5551:2018, 7.17, Method of making notches for cyclic corrosion, see Figure 1) was made on the side of each test panel where the topcoat was formed. Note that when making the notches, the notches were made deep enough to reach the substrate (down to the zinc-plated surface in the case of Substrate 1 and Substrate 2, and down to the steel sheet surface in the case of Substrate 3).

[0102] Each test panel with the notches as described above was subjected to a salt spray test based on JIS K 5600-7-1:1999, a combined cycle test based on Cycle D of JIS K 5600-7-9:2006, or an outdoor exposure test using an exposure rack based on JIS K 5600-7-6:2002. When Substrate 1 or Substrate 2 was used, the salt spray test and combined cycle test were each conducted for 1080 hours, and the outdoor exposure test was conducted for 6 months. When Substrate 3 was used, the salt spray test and combined cycle test were each conducted for 1440 hours. In these tests, if the corrosion protection of the formed corrosion-resistant coating is poor, a blister will occur from the point where the notch was made. Therefore, the maximum length from the notch to the tip of the blister at the point where the blister occurred was measured and evaluated based on the following evaluation criteria. The results are shown in Table 1 or 2. When blisters occurred at multiple locations, the longest of the maximum lengths measured at each location was used for the evaluation. When measuring this maximum length, locations within approximately 10 mm from the edge of the test plate were excluded from the evaluation. That is, as shown in Figure 1, the area other than approximately 10 mm from the edge of the test plate 1 with the cross-line cut 3 was designated as the evaluation area 2 (the colored area in Figure 1), and of the blisters that occurred in the evaluation area 2 after each test, the length (maximum length) from the cut 3 to the tip of the blisters farthest from the cut 3 was measured, and the following evaluation was performed.

[0103] (Evaluation criteria for salt spray tests and combined cycle tests when using substrate 1 and substrate 2) ◎: The maximum length is less than 3 mm ○: The maximum length is 3 mm or more and less than 5 mm ×: The maximum length is 5 mm or more.

[0104] (Evaluation criteria for outdoor exposure tests using substrate 1) ◎: The maximum length is less than 0.5 mm ○: The maximum length is 0.5 mm or more and less than 1.0 mm △: The maximum length is 1.0 mm or more and less than 1.5 mm ×: The maximum length is 1.5 mm or more.

[0105] (Evaluation criteria when using base material 3) 5: The maximum length is less than 2.5 mm 4: The maximum length is 2.5 mm or more and less than 4.0 mm 3: The maximum length is 4.0 mm or more and less than 5.0 mm 2: The maximum length is 5.0 mm or more and less than 6.0 mm 1: The maximum length is 6.0 mm or more

[0106] <Adhesion> Test plates were prepared using Substrate 1 in the same manner as in the preparation of the test plates described above. Using the obtained test plates, a salt spray test was conducted for 1080 hours in accordance with JIS K 5600-7-1:1999. Then, an adhesion test was conducted in accordance with the adhesion (cross-cut method) of JIS K 5600-5-6:1999 (cut interval: 3 mm). The adhesion between the hot-dip galvanized steel sheet and the corrosion-protective coating was evaluated based on the following evaluation criteria, in accordance with the classification in the JIS standard. The results are shown in Tables 1 and 2.

[0107] (Evaluation criteria) ○: Classification in the JIS standard is 0 or 1 △: Classification 2 in the JIS standard ×: Classification of JIS standard is 3 to 5

[0108] [Table 1]

[0109] [Table 2]

[0110] [Table 3] [Explanation of symbols]

[0111] 1: Test plate 2: Evaluation target part 3: Cut

Claims

1. an epoxy resin (A); an amine-based curing agent (B); an aluminum phosphate-based compound (C) other than aluminum diphosphate, aluminum triphosphate, and aluminum phosphite; at least one phosphorous compound (D) selected from aluminum phosphite compounds (D1) and zinc phosphite compounds (D2); Organic solvents and Contains the amine-based curing agent (B) contains at least one selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, metaxylylenediamine, isophoronediamine, and modified products of these amines; The content of the organic solvent is 10 to 50 mass %. An anticorrosion coating composition for forming an anticorrosion coating film on a zinc plating layer.

2. 2. The corrosion-protective coating composition according to claim 1, wherein the mass ratio ((D) / (C)) of the phosphorous acid-based compound (D) to the aluminum phosphate-based compound (C) is 0.2 to 5.

0.

3. 3. The corrosion-protective coating composition according to claim 1, wherein the total content of the aluminum phosphate-based compound (C) and the phosphorous-based compound (D) is 1.5 to 35 mass% relative to 100 mass% of the non-volatile content of the corrosion-protective coating composition.

4. The corrosion-protective coating composition according to any one of claims 1 to 3, wherein the epoxy resin (A) comprises an epoxy resin having an alkylphenol structure.

5. The corrosion-resistant coating composition according to any one of claims 1 to 4, wherein the organic solvent is an aliphatic hydrocarbon solvent or an aromatic hydrocarbon solvent having a boiling point of 150°C or higher.

6. A corrosion-resistant coating film formed from the 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 zinc-plated substrate.

8. A method for producing a substrate with a corrosion-resistant coating, comprising the following steps [1] and [2]: [1] A step of applying the anticorrosive coating composition according to any one of claims 1 to 5 onto the zinc plating layer of a zinc-plated substrate. [2] A step of drying the applied anticorrosion coating composition to form an anticorrosion coating film

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