Anti-rust paint composition, coated article, and method for producing coated article

Abstract

Provided is a rust-preventive coating composition capable of forming a rust-preventive coating film having excellent adhesion and rust prevention properties on rusted steel materials. [Solution] The anti-rust coating composition includes an epoxy resin (a), a polyamine (b), and a powder (c), wherein the powder (c) includes a metal sulfate (c-1) having a solubility of 0.1 g or more in 100 g of water at 5°C, and an alkaline earth metal compound (c-2) which is at least one of an alkaline earth metal oxide and an alkaline earth metal hydroxide, wherein the content of the metal sulfate (c-1) is 0.5% by mass or more and 10.0% by mass or less relative to 100% by mass of the resin solid content of the anti-rust coating composition, and the content of the alkaline earth metal compound (c-2) is 0.25% by mass or more and 10.0% by mass or less relative to 100% by mass of the resin solid content of the anti-rust coating composition, and the content of sulfate ions (SO4 2- ) and the number of moles of alkaline earth metal ions (M 2+ ) and the ratio of moles (M 2+ / SO4 2- ) is 0.4 or more and 2.0 or less, and the pigment volume concentration of the anticorrosive coating composition is 28.0% or more and 45.0% or less.

Description

[Technical Field]

[0001] The present invention relates to an anticorrosive coating composition, a coated article, and a method for producing a coated article. [Background technology]

[0002] Various paints have been proposed to improve the corrosion resistance of steel materials. For example, Patent Document 1 discloses a paint containing barium oxide and / or barium hydroxide and a metal sulfate. Patent Document 2 discloses a paint containing particles of at least one compound selected from the group consisting of calcium oxide, calcium hydroxide, strontium oxide, and strontium hydroxide, and particles of a metal sulfate, wherein the metal sulfate dissolves in an amount of 0.5 g or more in 100 g of water at 5°C, the compound particles have an average particle size of 17 μm or less, the metal sulfate particles have an average particle size of 17 μm or less, the compound particles are contained in an amount of 0.10 to 50.0 mass% based on the total solids content of the paint, and the metal sulfate particles are contained in an amount of 0.05 to 30.0 mass% based on the total solids content of the paint. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 069478 [Patent Document 2] International Publication No. 2019 / 069722 Summary of the Invention [Problem to be solved by the invention]

[0004] The paints of Patent Documents 1 and 2 react with the steel material or substances in the corrosive environment in the early stage when the coated steel material is exposed to a corrosive environment, forming an anticorrosion compound layer.

[0005] An object of the present invention is to provide an anti-rust coating composition that can impart excellent adhesion and anti-rust properties to rusted steel materials. [Means for solving the problem]

[0006] The present invention provides the following aspects. [1] an epoxy resin (a); a polyamine (b); A rust-preventive coating composition comprising: The powder (c) is A metal sulfate (c-1) with a solubility of 0.1 g or more in 100 g of water at 5°C; and an alkaline earth metal compound (c-2) which is at least one of an alkaline earth metal oxide and an alkaline earth metal hydroxide, the content of the metal sulfate (c-1) is 0.5% by mass or more and 10.0% by mass or less, based on 100% by mass of the resin solid content of the anticorrosive coating composition; the content of the alkaline earth metal compound (c-2) is 0.25% by mass or more and 10.0% by mass or less, based on 100% by mass of the resin solid content of the anticorrosive coating composition; The sulfate ions (SO4 2- ) and the number of moles of alkaline earth metal ions (M 2+ ) and the ratio of moles (M 2+ / SO4 2- ) is between 0.4 and 2.0, The anti-rust coating composition has a pigment volume concentration of 28.0% or more and 45.0% or less. [2] The anticorrosive coating composition according to [1] above, wherein the metal sulfate (c-1) comprises at least one selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, and zinc sulfate. [3] The rust-preventive coating composition of the above [1], wherein the alkaline earth metal compound (c-2) comprises at least one selected from the group consisting of calcium oxide, calcium hydroxide, barium oxide and barium hydroxide. [4] The anticorrosive coating composition of the above [1], further comprising at least one of zinc powder and zinc compound (c-3). [5] The anti-rust coating composition according to [1] above, which is for steel materials having rust on the surface. [6] The anti-rust coating composition according to [1] above, which is for steel materials having rust and salt on the surface. [7] The anti-rust coating composition of [1] above, wherein a coated article comprising a steel material having rust on its surface and an anti-rust coating film having a dry film thickness of 60 μm formed from the anti-rust coating composition is left to stand for 7 days in a humidity resistance tester at 50°C and 100% RH, and then the pull-off adhesion measured in accordance with JIS K 5600-5-7:2014 General test methods for paints - Part 5: Mechanical properties of coating films - Section 7: Adhesion (pull-off method) is 2.0 MPa or more. [8] A steel material having rust on its surface; A coated article comprising: an anti-rust coating film formed on the steel material using the anti-rust coating composition of [1] above. [9] The coated article of [8] above, wherein the thickness of the rust on the surface of the steel material is 10 μm or more and 200 μm or less.

[10] The coated article according to [8] above, wherein the anti-rust coating film covers rust on the surface of the steel material.

[11] The coated article according to [8] above, wherein the steel further has salt on the surface.

[12] A method for producing a coated article, comprising applying the anti-rust coating composition according to [1] above to a steel material having rust on its surface. [Effects of the Invention]

[0007] According to the present invention, there is provided an anti-rust coating composition capable of forming an anti-rust coating film having excellent adhesion and anti-rust properties on rusted steel materials. DETAILED DESCRIPTION OF THE INVENTION

[0008] The anticorrosion coating composition of the present disclosure converts rust formed on steel materials into an anticorrosion layer, thereby imparting anticorrosion properties to the steel materials. In the present disclosure, a metal sulfate (c-1) and an alkaline earth metal compound (c-2) are used in combination. According to the present disclosure, it is believed that excellent anticorrosion properties can be obtained by improving the adhesion of the anticorrosion coating film to the anticorrosion layer and the barrier properties of the anticorrosion coating film.

[0009] Metal sulfate (c-1) dissolves in the presence of water, generating sulfate ions and metal cations. The sulfate ions dissolve rust, generating iron ions. When dried, the iron ions and metal cations derived from metal sulfate (c-1) form a dense anti-rust layer with high rust-preventing properties. In other words, metal sulfate (c-1) converts the rust into a rust-preventing layer. Rust that forms on steel, especially red rust (Fe2O3), is brittle and easily broken. By converting the rust into a dense anti-rust layer, peeling between the anti-rust layer and the anti-rust coating is suppressed (i.e., adhesion is improved), and rust prevention is maintained for a long period of time.

[0010] However, excessive elution of metal sulfate (c-1) also results in excessive elution of rust, resulting in the formation of a sparse anti-corrosion layer. Furthermore, the elution of metal sulfate (c-1) also reduces the barrier properties of the anti-corrosion coating. Barrier properties refer to the ability to prevent corrosive factors such as water, oxygen, and ions from reaching the surface of a metal substrate and to suppress the corrosion current.

[0011] Therefore, alkaline earth metal compounds (c-2) are used in combination. Alkaline earth metal compounds dissolve in the presence of water, producing alkaline earth metal ions and their hydroxide ions. The alkaline earth metal ions react with sulfate ions to prevent excessive rust dissolution and control the rate and degree of rust conversion. Furthermore, the reaction product of alkaline earth metal ions and sulfate ions is sparingly soluble in water, and this fills the voids in the rust-preventive coating, improving the coating's barrier properties.

[0012] As described above, excellent rust prevention is achieved by balancing the rust conversion and the barrier properties of the coating film. In the present disclosure, the sulfate ions (SO4 2- ) and the number of moles of alkaline earth metal ions (M 2+ ) and the ratio of moles (M 2+ / SO4 2- ) is between 0.4 and 2.0.

[0013] Ratio (M 2+ / SO4 2- When the ratio (M) is 0.4 or more, rust is quickly converted into a rust-preventive layer, improving adhesion. 2+ / SO4 2- ) is 2.0 or less, excessive elution of rust is suppressed and the barrier properties of the rust-preventive coating film are improved.

[0014] In addition, the pigment volume concentration (PVC) of the anticorrosive coating composition of the present disclosure is 28.0% or more and 45.0% or less, where PVC is the volume percentage (%) of the total of the powder (C) and various pigments relative to the volume of the solid content of the anticorrosive coating composition.

[0015] By setting the pigment volume concentration to 28.0% or higher, the amount of resin components in the rust-preventive coating film is suppressed, making it easier for moisture to penetrate the rust-preventive coating film. This promotes the elution of the metal sulfate (c-1) and alkaline earth metal compound (c-2), allowing these functions to be effectively demonstrated. By setting the pigment volume concentration to 45.0% or lower, a certain amount of resin components in the rust-preventive coating film is ensured. This improves the strength of the rust-preventive coating film and improves adhesion. Furthermore, rapid moisture penetration is suppressed, reducing the occurrence of localized rust conversion. Overall rust conversion further improves adhesion.

[0016] (Anti-rust paint composition) The anticorrosive coating composition of the present disclosure comprises an epoxy resin (a), a polyamine (b), and a powder (c), which comprises a metal sulfate (c-1) having a solubility of 0.1 g or more in 100 g of water at 5°C, and an alkaline earth metal compound (c-2) which is at least one of an alkaline earth metal oxide and an alkaline earth metal hydroxide.

[0017] The content of the metal sulfate (c-1) is from 0.5 to 10.0 mass% based on 100 mass% of the resin solid content of the anticorrosive coating composition, and the content of the alkaline earth metal compound (c-2) is from 0.25 to 10.0 mass% based on 100 mass% of the resin solid content of the anticorrosive coating composition.

[0018] Sulfate ions (SO4 2- ) and the number of moles of alkaline earth metal ions (M 2+ ) and the ratio of moles (M 2+ / SO4 2- ) is 0.4 or more and 2.0 or less. The pigment volume concentration is 28.0% or more and 45.0% or less.

[0019] The anticorrosive coating composition may be a two-component type consisting of a base agent containing an epoxy resin (a) and a curing agent containing a polyamine (b). The powder (c) may be contained in the base agent, in the curing agent, or in both. The powder (c) may be contained in the base agent.

[0020] Hereinafter, the epoxy equivalent is determined based on the mass of the solid content, in accordance with JIS K 7236:2009.

[0021] The weight average molecular weight is measured by gel permeation chromatography (GPC).

[0022] The active hydrogen equivalent of the polyamine is determined based on the mass of the solid content in accordance with JIS K 7237:1995.

[0023] The solid content of the anticorrosive coating composition is the total content of the coating composition excluding volatile components (typically, solvents). The solid content concentration of the anticorrosive coating composition can be calculated from the residue when the coating composition is heated at 105°C for 1 hour in accordance with JIS K 5601-1-2:2008 Heating Residue Measurement Method.

[0024] The solid content concentration of the anti-rust coating composition is not particularly limited. The solid content concentration of the anti-rust coating composition may be, for example, 60% by mass or more and 75% by mass or less. The solid content concentration of the anti-rust coating composition may be 65% by mass or more, or 68% by mass or more. The solid content concentration of the anti-rust coating composition may be 73% by mass or less, or 71% by mass or less.

[0025] Epoxy resin (a) The epoxy resin (a) is a coating film-forming component that undergoes a crosslinking reaction with the polyamine (b) to form a cured coating film.

[0026] The epoxy resin (a) is not particularly limited. Examples of the epoxy resin (a) include aromatic epoxy resins such as bisphenol-type, novolac-type, biphenyl-type, and naphthalene-type; and aliphatic epoxy resins such as dicyclopentadiene-type and glycidyl ethers of polyhydric alcohols. These may be used alone or in combination of two or more. The epoxy resin (a) may be a modified product of the above-mentioned epoxy resin. In terms of moisture resistance and toughness, the epoxy resin may be an aromatic epoxy resin or a novolac-type epoxy resin.

[0027] Examples of bisphenol epoxy resins include bisphenol A, bisphenol F, bisphenol S, bisphenol AD, diglycidyl ethers of alkylene oxide adducts of these bisphenol epoxy resins, and hydrogenated bisphenol resins obtained by adding hydrogen to these bisphenol epoxy resins. These may be used alone or in combination of two or more.

[0028] Examples of novolac epoxy resins include phenol novolac, cresol novolac, and novolac of bisphenol A. These may be used alone or in combination of two or more.

[0029] Examples of biphenyl-, naphthalene-, and dicyclopentadiene-type resins include resins in which one or more glycidyl ether groups are substituted at any position of biphenyl, naphthalene, or dicyclopentadiene. These may be used alone or in combination of two or more.

[0030] The solid content of the epoxy resin (a) is, for example, 15% by mass or more and 60% by mass or less of the solid content of the anticorrosive coating composition. When the content of the epoxy resin (a) is 15% by mass or more, curability can be improved. When the content of the epoxy resin (a) is 60% by mass or less, the relative proportion of the pigment in the coating film increases, thereby improving hiding power. The content of the epoxy resin (a) may be 20% by mass or more, or may be 25% by mass or more. The content of the epoxy resin (a) may be 50% by mass or less, or may be 40% by mass or less.

[0031] The weight-average molecular weight of the epoxy resin (a) is not particularly limited. The weight-average molecular weight of the epoxy resin (a) may be 6,500 or more and 10,000 or less, in order to enhance curability (particularly curability at low temperatures of 5°C or less). The weight-average molecular weight of the epoxy resin (a) may be 8,500 or more. The weight-average molecular weight of the epoxy resin (a) may be 10,000 or less.

[0032] The epoxy equivalent of the epoxy resin (a) is not particularly limited. The epoxy equivalent of the epoxy resin (a) may be 1000 g / eq or more and 1400 g / eq or less, in order to improve curing properties at low temperatures. The epoxy equivalent of the epoxy resin (a) may be 1100 g / eq or more.

[0033] Commercially available novolac epoxy resins (a) include, for example, the trade name "EPICLON 5970-60" (phenol novolac epoxy resin, weight average molecular weight 9500, solid content 60 mass%, epoxy equivalent 1000 g / eq or more, manufactured by DIC Corporation). Commercially available bisphenol A epoxy resins (a) include, for example, the trade name "EPICLON 1040-70X" (bisphenol A epoxy resin, solid content 70 mass%, epoxy equivalent 1300 g / eq, manufactured by DIC Corporation).

[0034] Polyamine (b) The polyamine (b) is a curing component that undergoes a crosslinking reaction with the epoxy resin (a) to form a cured coating film.

[0035] The polyamine (b) is not particularly limited. The polyamine (b) may be an alicyclic polyamine (b-1) having a cyclic aliphatic hydrocarbon group to which an amino group is bonded, or a non-alicyclic polyamine (b-2) having no cyclic aliphatic hydrocarbon group to which an amino group is bonded, or may contain both. When the alicyclic polyamine (b-1) and the non-alicyclic polyamine (b-2) are used in combination, dissolution and lifting of the anticorrosive coating film formed by the anticorrosive coating composition is easily suppressed when another coating film is laminated on the anticorrosive coating film.

[0036] Examples of the alicyclic polyamine (b-1) include 1,4-cyclohexanediamine, 4,4'-methylenebiscyclohexylamine, 4,4'-isopropylidenebiscyclohexylamine, norbornadiamine, bis(aminomethyl)cyclohexane, diaminodicyclohexylmethane, isophoronediamine, menthenediamine (MDA), and 1,3-bis(aminomethyl)cyclohexane. These may be used alone or in combination of two or more.

[0037] The active hydrogen equivalent of the alicyclic polyamine (b-1) is, for example, 30 g / eq or more and 150 g / eq or less. When the active hydrogen equivalent of the alicyclic polyamine (b-1) is 30 g / eq or more, curability can be improved. When the active hydrogen equivalent of the alicyclic polyamine (b-1) is 150 g / eq or less, blocking function can be improved. The active hydrogen equivalent of the alicyclic polyamine (b-1) may be 32 g / eq or more, or 33 g / eq or more. The active hydrogen equivalent of the alicyclic polyamine (b-1) may be 100 g / eq or less, or 50 g / eq or less. The blocking function refers to the ability to prevent corrosive factors such as water, oxygen, and ions from reaching the surface of a metal substrate.

[0038] Examples of the non-alicyclic polyamine (b-2) include linear aliphatic polyamines, polyamines having an aromatic ring to which an amino group is bonded (aromatic polyamines), and polyamines having a heterocycle to which an amino group is bonded (heterocyclic polyamines). These may be used alone or in combination of two or more.

[0039] Examples of the chain aliphatic polyamine include alkylene polyamine and polyalkylene polyamine. The alkylene polyamine is, for example, HN-R 1 -NH2(wherein, R 1 is a divalent hydrocarbon group having 1 to 12 carbon atoms which may be substituted with one or more hydrocarbon groups having 1 to 10 carbon atoms, and may be branched. Examples of alkylene polyamines include methylene diamine, ethylene diamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, and 1,10-diaminodecane. Examples of polyalkylene polyamines include diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, and hexamethylene tetramine. These may be used alone or in combination of two or more.

[0040] Examples of linear aliphatic polyamines include tetra(aminomethyl)methane, tetrakis(2-aminoethylaminomethyl)methane, 1,3-bis(2'-aminoethylamino)propane, triethylene-bis(trimethylene)hexamine, bis(3-aminoethyl)amine, and bishexamethylenetriamine [HN(CH)NH(CH)NH]. These may be used alone or in combination of two or more.

[0041] Examples of aromatic polyamines include bis(aminoalkyl)benzenes, bis(aminoalkyl)naphthalenes, and compounds having two or more primary amino groups bonded to a benzene ring. Examples of aromatic polyamines include bis(cyanoethyl)diethylenetriamine, o-xylylenediamine, m-xylylenediamine (MXDA), p-xylylenediamine, phenylenediamine, naphthylenediamine, diaminodiphenylmethane, diaminodiethylphenylmethane, 2,2-bis(4-aminophenyl)propane, 4,4'-diaminodiphenylether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylsulfone, 2,2'-dimethyl-4,4'-diaminodiphenylmethane, 2,4'-diaminobiphenyl, 2,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, bis(aminomethyl)naphthalene, and bis(aminoethyl)naphthalene. These may be used alone or in combination of two or more.

[0042] Examples of heterocyclic polyamines include N-methylpiperazine [CH3-N(CH2CH2)2NH], morpholine [HN(CH2CH2)2O], 1,4-bis-(8-aminopropyl)-piperazine, piperazine-1,4-diazacycloheptane, 1-(2'-aminoethylpiperazine), 1-[2'-(2''-aminoethylamino)ethyl]piperazine, 1,11-diazacycloeicosane, and 1,15-diazacyclooctacosane. These may be used alone or in combination of two or more.

[0043] The active hydrogen equivalent of the non-alicyclic polyamine (b-2) is, for example, 30 g / eq or more and 550 g / eq or less. The active hydrogen equivalent of the non-alicyclic polyamine (b-2) may be 32 g / eq or more, or 35 g / eq or more. The active hydrogen equivalent of the non-alicyclic polyamine (b-2) may be 250 g / eq or less, 100 g / eq or less, or 50 g / eq or less.

[0044] The solid content of polyamine (b) is, for example, 0.6% by mass or more and 15% by mass or less of the solid content of the anticorrosive coating composition. When the content of polyamine (b) is 0.6% by mass or more, curability can be improved. When the content of polyamine (b) is 15% by mass or less, barrier function can be improved. The content of polyamine (b) may be 0.8% by mass or more, or 0.9% by mass or more. The content of polyamine (b) may be 10% by mass or less, 5.0% by mass or less, or 2.0% by mass or less.

[0045] The solid content of the alicyclic polyamine (b-1) is, for example, 0.5% by mass or more and 10% by mass or less of the solid content of the anticorrosive coating composition. When the content of the alicyclic polyamine (b-1) is 0.5% by mass or more, curing properties can be improved, particularly at low temperatures. When the content of the alicyclic polyamine (b-1) is 10% by mass or less, the tackiness (adhesion) of the resulting coating film can be reduced, and the treadability can be improved. The content of the alicyclic polyamine (b-1) may be 0.6% by mass or more, 0.7% by mass or more, or 0.75% by mass or more. The content of the alicyclic polyamine (b-1) may be 8.0% by mass or less, 6.0% by mass or less, or 2.0% by mass or less. The treadability refers to the ability of a coating film to be less likely to leave shoe marks and to peel off when a worker walks on the coating film.

[0046] The solid content of the non-alicyclic polyamine (b-2) is, for example, 0% by mass or more and 10% by mass or less of the solid content of the anticorrosive coating composition. When the content of the non-alicyclic polyamine (b-2) is 10% by mass or less, the tackiness of the resulting coating film at low temperatures is reduced and the treadability can be improved. The content of the non-alicyclic polyamine (b-2) may be 0.1% by mass or more, or 0.15% by mass or more. The content of the non-alicyclic polyamine (b-2) may be 6.0% by mass or less, 3.0% by mass or less, 2.0% by mass or less, or 1.0% by mass or less.

[0047] Alkylphenol The curing agent may further include an alkylphenol, which further improves curability (especially low-temperature curability).

[0048] Examples of alkylphenols include monohydric phenols such as methylphenol (o, m, p-cresol), ethylphenol, butylphenol, tert-butylphenol, octylphenol, nonylphenol, dodecylphenol, and dinonylphenol. These may be used alone or in combination of two or more. The number of carbon atoms in the alkyl group of the alkylphenol is, for example, 1 to 10. The number of carbon atoms may be 5 or less.

[0049] The solid content of the alkylphenol is, for example, 0.05% by mass or more and 5.0% by mass or less of the solid content of the anticorrosive coating composition. The content of the alkylphenol may be 0.1% by mass or more, or 0.15% by mass or more. The content of the alkylphenol may be 3.0% by mass or less, 2.0% by mass or less, 1.0% by mass or less, or 0.4% by mass or less.

[0050] ·Powder (c) The powder (c) contains a rust inhibitor. By using a specific metal sulfate (c-1) in combination with an alkaline earth metal compound (c-2) as the rust inhibitor, it is possible to impart excellent rust prevention properties to rusted steel materials, as described above.

[0051] The average particle size of the powder (c) is, for example, 0.1 μm or more and 40 μm or less. The average particle size of the powder (c) may be 5 μm or more. The average particle size of the powder (c) may be 20 μm or less.

[0052] The average particle size of the powder (c) is calculated as follows: A composition containing an epoxy resin (a), a polyamine (b), and a metal sulfate (c-1) in a predetermined ratio is applied to a polished steel plate to form a dry coating film of 100 μm or more, and then dried. The cross section of the resulting coating film in the thickness direction is observed with a scanning electron microscope (SEM). The maximum diameters in a specific direction of 200 particles of metal sulfate (c-1) observed in the image are measured, and the average value is calculated. This average value is the average particle size of the metal sulfate (c-1). The average particle sizes of the zinc compound (c-3) and the alkaline earth metal compound (c-2) described below can also be determined in the same way.

[0053] Metal sulfates (c-1) The metal sulfate (c-1) dissolves in an amount of 0.1 g or more in 100 g of water at 5°C. The metal sulfate (c-1) is easily dissolved in water even in a low-temperature environment, and therefore can promote the formation of a rust-preventive layer. The dissolution amount of the metal sulfate (c-1) may be 5.0 g or more, or may be 10.0 g or more.

[0054] The metal sulfate (c-1) may be a salt of a polyvalent metal cation and a sulfate ion. The polyvalent metal cation (hereinafter referred to as the polyvalent cation) coexists with the iron ion generated from the metal substrate, thereby forming a dense and electrochemically stable anticorrosive layer.

[0055] Examples of metals constituting the metal sulfate (c-1) include alkaline earth metals, transition metals, and post-transition metals. These metals generate polyvalent cations. These metals may be used alone or in combination of two or more.

[0056] Alkaline earth metals are elements in Group 2 of the periodic table. Specific examples of alkaline earth metals include magnesium (Mg), calcium (Ca), and strontium (Sr). Transition metals are metallic elements that exist between Groups 3 and 11 of the periodic table. Specific examples of transition metals include scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), and rhodium (Rh). Examples of post-transition metals include palladium (Pd), silver (Ag), cadmium (Cd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg), rutherfordium (Rf), dubnium (Db), seaborgium (Sg), bohrium (Bh), and hassium (Hs). Post-transition metals are metal elements in the P-block of the periodic table. Specific examples of post-transition metals include aluminum (Al), gallium (Ga), indium (In), tin (Sn), thallium (Tl), lead (Pb), bismuth (Bi), polonium (Po), and astatine (At). From the viewpoint of solubility, the metal may be magnesium (Mg), aluminum (Al), nickel (Ni), or zinc (Zn). These may be used alone or in combination of two or more.

[0057] Examples of the metal sulfate (c-1) include nickel sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. These may be used alone or in combination of two or more.

[0058] The metal sulfate (c-1) may contain at least one selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, and zinc sulfate.

[0059] The content of the metal sulfate (c-1) is 0.5% by mass or more and 10.0% by mass or less, based on 100% by mass of the resin solid content of the anticorrosive coating composition. When the content of the metal sulfate (c-1) is 0.5% by mass or more, the conversion of rust to a rust-preventive layer is more likely to proceed. When the content of the metal sulfate (c-1) is 10.0% by mass or less, excessive elution of rust is more suppressed.

[0060] The content of the metal sulfate (c-1) may be 1.0 mass% or more, 2.0 mass% or more, or 3.0 mass% or more. The content of the metal sulfate (c-1) may be 9.0 mass% or less, 7.5 mass% or less, or 5.0 mass% or less. The content of the metal sulfate (c-1) may be 1.0 mass% or more and 9.0 mass% or less, 2.0 mass% or more and 9.0 mass% or less, or 3.0 mass% or more and 7.5 mass% or less.

[0061] Alkaline earth metal compounds (c-2) The powder (c) contains an alkaline earth metal compound (c-2). The alkaline earth metal compound (c-2) is at least one of an oxide and a hydroxide of an alkaline earth metal. As described above, the alkaline earth metal compound (c-2) controls the rate and degree of rust conversion and improves the barrier properties of the rust-preventive coating film.

[0062] The amount of alkaline earth metal compound (c-2) dissolved is not particularly limited. The amount of alkaline earth metal compound (c-2) dissolved in 100 g of water at 20°C may be 0.05 g or more. The amount of alkaline earth metal compound (c-2) dissolved may be 0.1 g or more, or 1.0 g or more. From the viewpoint of suppressing the generation of voids due to rapid dissolution, the amount of alkaline earth metal compound (c-2) dissolved may be 5.0 g or less, or 4.0 g or less.

[0063] The alkaline earth metal is not particularly limited and may be any of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). The alkaline earth metal may be at least one selected from the group consisting of Ca, Sr, and Ba.

[0064] Specific examples of the alkaline earth metal compound (c-2) include calcium oxide, barium oxide, strontium oxide, calcium hydroxide, barium hydroxide, and strontium hydroxide. The alkaline earth metal compound (c-2) may contain at least one selected from the group consisting of calcium oxide, calcium hydroxide, barium oxide, and barium hydroxide. Among these, calcium oxide may be contained.

[0065] The content of the alkaline earth metal compound (c-2) is 0.25% by mass or more and 10.0% by mass or less, based on 100% by mass of the resin solids content of the rust-preventive coating composition. When the content of the alkaline earth metal compound (c-2) is within the above range, the rate and degree of rust conversion can be well controlled, and the barrier properties of the rust-preventive coating film can be further improved.

[0066] The content of alkaline earth metal compound (c-2) may be 1.0 mass% or more, 2.0 mass% or more, or 3.0 mass% or more. The content of alkaline earth metal compound (c-2) may be 8.0 mass% or less, or 5.0 mass% or less. The content of alkaline earth metal compound (c-2) may be 1.0 mass% or more and 8.0 mass% or less, 2.0 mass% or more and 8.0 mass% or less, or 3.0 mass% or more and 5.0 mass% or less.

[0067] Sulfate ions (SO4 2- ) and the number of moles of alkaline earth metal ions (M 2+ ) and the ratio of moles (M 2+ / SO4 2- ) is between 0.4 and 2.0.

[0068] Ratio (M 2+ / SO4 2- ) may be 0.6 or more, and may be 0.8 or more. 2+ / SO4 2- ) may be 1.6 or less, or may be 1.4 or less. 2+ / SO4 2- ) may be 0.6 or more and 1.6 or less, or 0.8 or more and 1.4 or less.

[0069] Zinc and zinc compounds (c-3) Powder (c) may further contain at least one of zinc dust and zinc compound (c-3). Zinc dust and zinc compound (c-3) provide zinc ions to the coating film. The zinc ions dissolve in the coating film as the pH changes due to the progression of corrosion of the coated substrate, and form basic zinc chloride together with chloride ions. Zinc chloride is a dense and highly rust-resistant compound, which can improve the barrier function of the rust-preventive coating film. In particular, white zinc compound (c-3) may be used.

[0070] The zinc compound (c-3) dissolves in 100 g of water at pH 7.0 and 20° C. in an amount of less than 0.03 g, and dissolves in 100 g of water at pH 4.0 and 20° C. in an amount of 0.03 g or more.

[0071] The zinc compound (c-3) has a low solubility in 100 g of water at 20°C in the range from nearly neutral to alkaline. Therefore, the dissolution of the zinc compound (c-3) is suppressed in an environment where corrosion is unlikely to progress. On the other hand, in the acidic range, the zinc compound (c-3) has a high solubility in 100 g of water at 20°C. The zinc compound (c-3) dissolves and exerts its effect as the pH decreases due to the dissolution of the metal sulfate (c-1).

[0072] Examples of the zinc compound (c-3) include zinc oxide, zinc hydroxide, and zinc carbonate. These may be used alone or in combination of two or more. From the viewpoint of hiding power, zinc oxide may be included.

[0073] The content of zinc dust and zinc compound (c-3) is 10.0 mass% or more and 65.0 mass% or less, based on 100 mass% of the resin solid content of the anticorrosive coating composition. When the content of zinc dust and zinc compound (c-3) is 10.0 mass% or more, the effects of zinc dust and zinc compound (c-3) are fully exhibited. When the content of zinc dust and zinc compound (c-3) is 65.0 mass% or less, film-forming properties are not impaired.

[0074] The content of zinc dust and zinc compound (c-3) may be 25.0% by mass or more, 35.0% by mass or more, or 40.0% by mass or more. The content of zinc dust and zinc compound (c-3) may be 60.0% by mass or less, or 55.0% by mass or less. The content of zinc dust and zinc compound (c-3) may be 25.0% by mass or more and 60.0% by mass or less, 35.0% by mass or more and 60.0% by mass or less, or 40.0% by mass or more and 55.0% by mass or less.

[0075] The mass ratio (c-1 / c-3) of the content of the metal sulfate (c-1) to the content of the zinc powder and zinc compound (c-3) may be, for example, 6 / 94 to 75 / 25. This further promotes the ionization of the zinc powder and zinc compound (c-3), allowing for efficient production of zinc chloride. The ratio (c-1 / c-3) may be 8 / 92 to 70 / 30, or 10 / 90 to 50 / 50.

[0076] Other rust inhibitors (c-4) Powder (c) may contain a rust inhibitor (c-4) other than those described above. The other rust inhibitor (c-4) is not particularly limited as long as it does not interfere with the effects of the present disclosure. Examples of the other rust inhibitor (c-4) include those commonly used as rust inhibitors. Examples of the other rust inhibitor (c-4) include calcium phosphite, aluminum phosphate, zinc phosphate, zinc molybdate, aluminum molybdate, and aluminum powder. These may be used alone or in combination of two or more.

[0077] The content of the other rust inhibitor (c-4) is, for example, 8% by mass or less of the solid content of the anticorrosive coating composition, and the content of the other rust inhibitor (c-4) may be 5% by mass or less, 3% by mass or less, or 0% by mass.

[0078] Thickener The anticorrosive coating composition may contain a thickener. The thickener adjusts the viscosity of the anticorrosive coating composition (including the high shear viscosity and low shear viscosity described below). Thickeners include thixotropic agents, thixotropic agents, rheology control agents, and viscosity modifiers.

[0079] The content of the thickener is appropriately determined depending on the other components contained in the anticorrosive coating composition and their amounts. The content of the thickener may be, for example, 0.2% by mass or more and 2.5% by mass or less of the solid content of the anticorrosive coating composition. The content of the thickener may be 0.4% by mass or more, or 0.6% by mass or more. The content of the thickener may be 2.0% by mass or less, or 1.0% by mass or less.

[0080] The thickener is not limited as long as it is a non-aqueous thickener. Examples of thickeners include inorganic, organic, and composites thereof. These may be used alone or in combination of two or more.

[0081] Inorganic thickeners include, for example, finely divided silica, clay minerals, and ultrafine precipitated calcium carbonate, which form a finely dispersed colloidal structure.

[0082] Examples of organic thickeners include metal soaps, hydrogenated castor oils, polyamide waxes, polyethylene oxides, vegetable oils, polymerized oils, and surfactants. These form a network structure, a colloidal dispersion structure, or an aggregate structure due to adsorption onto pigments, etc.

[0083] Examples of organic-inorganic composite thickeners include organic bentonite and surface-treated calcium carbonate, which form a finely dispersed colloidal structure.

[0084] Among these, polyamide wax-based thickeners are preferred because they are more likely to provide optimal thixotropy. Thixotropy is the property of a material being more likely to develop viscosity at low shear and less likely to develop viscosity at high shear.

[0085] Pigments The anticorrosive coating composition may contain a pigment. Examples of the pigment include, without limitation, pigments that are typically incorporated into coating compositions. Examples of the pigment include extender pigments and coloring pigments. These may be used alone or in combination of two or more.

[0086] The anti-rust coating composition may contain a white pigment. The white pigment improves the hiding power of the anti-rust coating composition while minimizing the effect on the hue of the topcoat. If the anti-rust coating composition has sufficient hiding power, the white pigment need not be contained. A representative example of the white pigment is titanium dioxide. The content of the white pigment is not particularly limited. The content of the white pigment may be, for example, 5.0% by mass or more and 60.0% by mass or less of the solid content of the anti-rust coating composition. The content of the white pigment may be 10.0% by mass or more, 15.0% by mass or more, or 20.0% by mass or more. The content of the white pigment may be 40.0% by mass or less, or 30.0% by mass or less.

[0087] · Extender pigment Examples of extender pigments include talc, clay, calcium carbonate, magnesium carbonate, barium sulfate, silicic acid, silicates, aluminum oxide hydrate, calcium sulfate, gypsum, micaceous iron oxide (MIO), glass flakes, szolite mica, and clarite mica. These may be used alone or in combination of two or more. The amount of extender pigment is not particularly limited.

[0088] Color pigments other than white Examples of color pigments include carbon black, graphite, zinc sulfide, chromium oxide, yellow nickel titanium, yellow chromium titanium, yellow iron oxide, red iron oxide, black iron oxide, phthalocyanine blue, phthalocyanine green, ultramarine blue, quinacridones, and azo-based red and yellow pigments. These may be used alone or in combination of two or more. The content of the color pigment is not particularly limited.

[0089] The total content of the powder (C) and various pigments is 28.0% or more and 45.0% or less in terms of pigment volume concentration (PVC).

[0090] The PVC may be 30.0% or more, or 33.0% or more. The PVC may be 40.0% or less, or 37.0% or less. The PVC may be 30.0% or more and 40.0% or less, or 33.0% or more and 37.0% or less.

[0091] Other resins The anticorrosive coating composition may contain resins other than the epoxy resin (a). Examples of other resins include xylene resins, acrylic resins, and polyester resins. These may be used alone or in combination of two or more.

[0092] ·solvent The anticorrosive coating composition may contain a solvent. The content of the solvent is, for example, 5% by mass or more and 50% by mass or less of the total mass of the anticorrosive coating composition.

[0093] Examples of the solvent include those commonly used in the art, such as toluene, xylene, isobutyl alcohol, methyl ethyl ketone, and weak solvents, which may be used alone or in combination of two or more.

[0094] The anticorrosive coating composition may contain a weak solvent. The content of the weak solvent is, for example, 5% by mass or more and 50% by mass or less of the total mass of the anticorrosive coating composition.

[0095] Weak solvents are aliphatic hydrocarbon compounds. Examples of weak solvents include single-component solvents such as n-butane, n-hexane, n-heptane, n-octane, isononane, n-decane, n-dodecane, cyclopentane, cyclohexane, and cyclobutane; and mixed solvents such as mineral spirits, white spirits, mineral turpentine, isoparaffin, solvent kerosene, aromatic naphtha, VM&P naphtha, and solvent naphtha. These solvents can be used alone or in combination.

[0096] Commercially available weak solvents include "Solvesso 100," "Solvesso 150," and "Solvesso 200" (all trade names, manufactured by Esso Oil Co., Ltd.), "Swasol 310," "Swasol 1000," and "Swasol 1500" (all trade names, manufactured by Cosmo Oil Co., Ltd.).

[0097] ·others The anticorrosive coating composition may contain other components, such as a silane coupling agent and various additives.

[0098] The silane coupling agent improves adhesion between the anticorrosive coating film and the metal substrate. The silane coupling agent may have at least one of a trimethoxysilyl group and a triethoxysilyl group. The content of the silane coupling agent may be 0.5% by mass or more and 5% by mass or less, based on the total mass of the anticorrosive coating composition.

[0099] Examples of the additives include anti-sagging agents, anti-settling agents, anti-color separation agents, anti-foaming agents, anti-popping agents, leveling agents, and matting agents.

[0100] ·Preparation method The two-component anticorrosive coating composition is prepared by mixing the base agent, the curing agent, and, if necessary, the diluent, etc., by the method described above. The base agent and the curing agent are usually mixed immediately before use (for example, the composition is used within 60 minutes after mixing the components). The diluent can be exemplified by the solvents described above.

[0101] The base agent is prepared by mixing the above components by a method known to those skilled in the art. For mixing, a commonly used mixing device such as a paint shaker or mixer is used. The same method is used to prepare the curing agent.

[0102] Pull-off adhesion The anti-rust coating film obtained by the present disclosure has excellent adhesion to anti-rust layers. For example, a coated article comprising a steel material having rust on its surface and an anti-rust coating film formed from the anti-rust coating composition and having a dry film thickness of 60 μm is left in a humidity resistance tester at 50°C and 100% RH for 7 days, and then the pull-off adhesion measured in accordance with JIS K 5600-5-7:2014 General test methods for paints - Part 5: Mechanical properties of coating films - Section 7: Adhesion (pull-off method) is 2.0 MPa or more.

[0103] The pull-off adhesion may be 3.0 MPa or more. The pull-off adhesion may be 10.0 MPa or less, or 8.0 MPa or less. The pull-off adhesion may be 2.0 MPa or more and 10.0 MPa or less, or 3.0 MPa or more and 8.0 MPa or less.

[0104] (painted items) A coated article according to one embodiment of the present disclosure comprises a steel material having rust on its surface, and an anti-rust coating film formed on the steel material from the anti-rust coating composition according to the present disclosure.

[0105] The anti-rust coating film preferably covers the rust on the surface of the steel material. Covering the rust on the surface of the steel material with the anti-rust coating film means that the rust is not directly visible when the coated article is viewed from above.

[0106] ·Steel material The steel material may be a primary steel product obtained by forming and / or processing steel by rolling (rolled steel material), forging (steel forgings), casting (steel castings), or the like. A typical example of the steel material is a plate-shaped steel material (steel sheet). Specific examples of the steel sheet include cold-rolled steel sheets, hot-rolled steel sheets, electrogalvanized steel sheets, hot-dip galvanized steel sheets, zinc-aluminum alloy-plated steel sheets, zinc-iron alloy-plated steel sheets, zinc-magnesium alloy-plated steel sheets, zinc-aluminum-magnesium alloy-plated steel sheets, aluminum-plated steel sheets, aluminum-silicon alloy-plated steel sheets, and tin-plated steel sheets. The steel material may be a secondary steel product such as a painted color steel sheet or a coated steel sheet having a resin layer.

[0107] Specific examples of the substrates include ships, vehicles (e.g., railway vehicles, large vehicles), aircraft, bridges, offshore structures, plants, tanks (e.g., oil tanks), pipes, steel pipes, cast iron pipes, and other steel structures and buildings.

[0108] The steel may be subjected to blasting, anti-rust coating, shop primer coating, or organic or inorganic zinc-rich primer coating. The steel sheet may have a previous coating film (a coating film other than the above-mentioned anti-rust coating film that was formed before the above-mentioned anti-rust coating film was formed).

[0109] The thickness of the rust is not particularly limited, but may be 10 μm or more and 200 μm or less. Even if the rust thickness is 30 μm or more, the rust-preventive coating film can be formed to cover the entire rust on the surface of the steel material. The rust thickness may be 150 μm or less, or may be 100 μm or less. The rust-preventive coating composition of the present disclosure exhibits high rust prevention properties even on steel materials with rust 200 μm thick.

[0110] The thickness of the rust is measured using an electromagnetic induction type film thickness meter (for example, Kett's product name "LZ-370") as follows. First, zero-point calibration is performed on a portion of the rusted steel material from which the rust has been sufficiently removed. Then, the thickness is measured at any five points where rust is present, and the average value is taken as the rust thickness. If the steel material is available before rust develops, zero-point calibration may be performed at any point on the steel material before rust develops.

[0111] Rust is a corrosion product produced by an oxidation-reduction reaction of metal atoms contained in steel. Rust includes corrosion products such as precipitate films, oxide films, hydroxide films, and oxyhydroxide films. Rust usually exists in the form of a film on the surface of steel, and may also exist in the form of pitting corrosion. The surface of steel refers to, for example, the surface exposed to the outside air, and may include invisible and untouchable parts. Major components of rust include iron compounds such as iron oxide, iron hydroxide, iron oxyhydroxide, and iron carbonate. Rust may also contain salts composed of non-ferrous metal cations such as zinc and anions such as phosphate, molybdate, and sulfate ions. A resin layer or coating may remain on the surface of the rust.

[0112] A coated article according to another embodiment of the present disclosure comprises a steel material having rust and salt on its surface, and an anti-rust coating film formed on the steel material using the anti-rust coating composition of the present disclosure.

[0113] The salt concentration on the steel surface is not particularly limited. For example, the salt concentration on the steel surface is 5 mg / m 2 may be 30 mg / m or more, 2 may be 50 mg / m or more, 2 may be 75 mg / m or more 2 may be greater than or equal to 100 mg / m 2 may be 200 mg / m or more, 2 The anticorrosive coating composition of the present disclosure exhibits high anticorrosion properties even on steel materials having high concentrations of salt.

[0114] The salt concentration on the steel surface can be obtained as follows. First, pure water is poured into the measurement cell in which the object to be measured is fixed. After pouring, the stirring function of the device is started. This stirring start point is the starting point of the measurement. The electrical conductivity of the water is measured one minute after the start of the measurement. This measurement value is converted into the water-soluble salt concentration or sodium chloride concentration, and the resulting value is the salt concentration (mg / m) on the steel surface. 2 The salinity concentration can be measured using, for example, the "Surface Salinity Meter SNA-3000" manufactured by Sanko Electronics Laboratory.

[0115] Anti-rust coating The anticorrosive coating composition forms an anticorrosive coating film with excellent anticorrosive properties. The thickness of the anticorrosive coating film is not particularly limited and can be appropriately set depending on the type of substrate, application, etc. The dry film thickness of the anticorrosive coating film is, for example, 30 μm or more and 300 μm or less. The anticorrosive coating composition may be applied multiple times to form an anticorrosive coating film with a laminated structure.

[0116] The dry film thickness of the rust-preventive coating film may be 60 μm or more, or may be 120 μm or more. The dry film thickness of the rust-preventive coating film may be 240 μm or less, or may be 180 μm or less. The dry film thickness of the rust-preventive coating film may be 60 μm or more and 240 μm or less, or may be 120 μm or more and 180 μm or less.

[0117] The dry film thickness of the anti-rust coating is measured using an electromagnetic induction type film thickness meter (for example, Kett, product name "LZ-370") as follows. First, zero-point calibration is performed at any point on the steel before rust occurs, or at a portion of the steel after painting from which the anti-rust coating has been sufficiently removed. Then, the thickness is measured at any five points on the anti-rust coating, and the dry film thickness of the anti-rust coating is determined by subtracting the rust thickness obtained by the above method from the average value.

[0118] The dry film thickness may also be theoretically calculated from the following formula based on information on the coating amount, specific gravity, solid content and specific gravity of the volatile content of the anticorrosive coating composition.

[0119] y=x×[(1 / dt)-{(100-NV) / (100×ds)}] x: Application amount [g / m 2 ] y: Dry film thickness [μm] z: Wet film thickness [μm] dt: specific gravity of paint [g / cm 3 ] NV: Heat residue of paint [wt%] ds: specific gravity of volatile matter (solvent in paint) [g / cm 3 ]

[0120] Furthermore, the thickness z (μm) of the anti-rust coating film before drying (wet film thickness) can be calculated by z=x / dt.

[0121] Other coatings Other coating films may be formed on the anticorrosive coating film, such as topcoat paints and / or functional paints.

[0122] Examples of topcoat paint compositions include oil-based paints, long-oil phthalic acid resin paints, silicone alkyd resin paints, phenolic resin paints, chlorinated rubber resin paints, epoxy resin paints, modified epoxy resin paints, tar epoxy resin paints, vinyl chloride resin paints, polyurethane resin paints, fluororesin paints, and silicone-modified resin paints. Examples of functional paints include photocatalytic paints that exhibit self-cleaning properties against pollutants, and antifouling paints that prevent the adhesion of marine organisms, etc.

[0123] (Manufacturing method of coated article) The coated article of the present disclosure is produced by a method comprising painting the anticorrosive coating composition of the present disclosure onto a steel material having rust (and further salt) on its surface.

[0124] Painting method The coating method is not particularly limited, and the anti-rust coating composition is applied to the steel material by a common method such as with a brush, a roller, or a spray.

[0125] The anticorrosive coating composition can be allowed to dry naturally at room temperature (23°C ± 3°C) for 2 hours or more, 24 hours or more, or even one week or more. [Example]

[0126] Hereinafter, the present embodiment will be described in more detail using examples, but the present embodiment is not limited to these examples. In the examples, "parts" and "%" are by mass unless otherwise specified.

[0127] [Production Example 1] Preparation of novolac epoxy resin (a1) A 2-L reactor equipped with a thermometer, stirrer, and condenser and a water separator was charged with 250 g of p-tert-butylphenol novolac resin (trade name: Hitanol #1133, Hitachi Chemical Co., Ltd.), 250 g of octylphenol novolac resin (trade name: Hitanol #1501, Hitachi Chemical Co., Ltd.), and 1,440 g of epichlorohydrin, and stirred to form a homogeneous solution. Next, 268 g of 48% by mass sodium hydroxide was added dropwise at 60-110°C over 2 hours. During this time, the water generated in the system was azeotropically distilled with epichlorohydrin and removed from the system using a water separator, while the epichlorohydrin was refluxed within the system. After the dropwise addition, the mixture was aged at 100-120°C for 2 hours, and the reaction was terminated when the theoretical amount of water had been extracted.

[0128] 150 g of xylene was added to the resulting epichlorohydrin solution of the epoxy compound, and the mixture was washed with a large amount of water. After removing the resulting salt and excess sodium hydroxide, the mixture was neutralized with a 3% by mass aqueous solution of phosphoric acid. The epichlorohydrin and xylene were then distilled off under reduced pressure, and 460 g of a high-boiling paraffin solvent (product name: Swazol 310, manufactured by Cosmo Oil Co., Ltd.) was added to obtain a liquid epoxy resin (a) (novolac-type epoxy resin). The epoxy resin (a) had a weight-average molecular weight of 8,500, an epoxy equivalent of 1,010 g / eq, and a solids content of 60% by mass.

[0129] [Examples 1 to 45, Comparative Examples 1 to 24] The base agent and curing agent were each prepared according to the formulation shown in Tables 1 to 9. The base agent and curing agent were mixed to prepare anti-rust coating compositions. Unless otherwise specified, the blending amounts in Tables 1 to 9 are mass ratios relative to 100 mass parts of the solid content of the anti-rust coating composition. A weak solvent (trade name "Solvesso 100", manufactured by Esso Oil Co., Ltd.) and a strong solvent (xylene, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added in appropriate amounts so that the solid content concentration (NV) of the anti-rust coating composition would be as shown in Tables 1 to 9.

[0130] Details of each component shown in Tables 1 to 9 are as follows. Epoxy resin (a) Bisphenol A epoxy resin: trade name "jER1007", manufactured by Mitsubishi Chemical Corporation, weight average molecular weight 10,000, epoxy equivalent 1975 g / eq, solid content 100% by mass

[0131] Polyamine (b) Alicyclic polyamine (b-1): 1,3-bis(aminomethyl)cyclohexane, manufactured by Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent: 34.2 g / eq, weight average molecular weight: 142.24 Non-alicyclic polyamine (b-2): m-xylylenediamine, manufactured by Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent: 35.5 g / eq, weight-average molecular weight: 136.19

[0132] Alkylphenol o-tert-butylphenol thickener Product name: "F-9050", manufactured by Kusumoto Chemicals Co., Ltd., a mixture of aliphatic amide wax and oxidized polyolefin wax Antifoaming agents Product name: Disparlon 1958, manufactured by Kusumoto Chemicals Weak solvent Product name: Solvesso 100, manufactured by Exxon Mobil

[0133] Metal sulfates (c-1) The amount dissolved in 100g of water at 5°C is shown in parentheses. Aluminum sulfate (32.2g) Nickel sulfate hexahydrate (39.1 g) Magnesium sulfate (25.4g) Zinc sulfate (44.4g)

[0134] Alkaline earth metal compounds (c-2) The amount dissolved in 100g of water at 20°C is shown in parentheses. Calcium oxide (0.112g) Barium oxide (3.48g) Calcium hydroxide (0.173g) Barium hydroxide (3.89g)

[0135] Zinc compounds (c-3) The amounts dissolved in 100g of water at 20°C at pH 4.0 and pH 7.0 are shown in parentheses. Zinc carbonate (pH 4.0: >8.13 g, pH 7.0: 0.000470 g) Zinc oxide (pH 4.0: >12.5g, pH 7.0: 0.000394g) Zinc hydroxide (pH 4.0: >13.1 g, pH 7.0: 0.000425 g)

[0136] The average particle size of each type of powder (c) was 0.1 to 40 μm.

[0137] [Measurement method] (i) Thickness of rust on the steel plate surface Using an electromagnetic induction film thickness meter (manufactured by Kett, product name "LZ-370"), zero point calibration was performed at any point on a TP Giken SS400 grid blast steel plate before rust had formed.Then, the thickness was measured at any five points where rust had formed, and the average value was taken as the rust thickness.

[0138] (ii) Thickness of anti-rust coating Using an electromagnetic induction film thickness meter (Kett, product name "LZ-370"), zero point calibration was performed at any point on a TP Giken SS400 grid-blasted steel plate before rusting. After painting, the thickness of the anti-rust coating was measured at any five points, and the average value was calculated by subtracting the thickness of the rust obtained by the above method. This was used as the dry film thickness of the anti-rust coating.

[0139] [evaluation] The anticorrosive coating compositions were evaluated by the following methods, and the evaluation results are shown in Tables 1 to 9.

[0140] (1) Rust prevention (rust prevention for steel plates containing rust and salt) TP Giken SS400 grid-blasted steel plates were exposed to the coastal area of ​​Tamano City, Okayama Prefecture for three months to obtain rusted steel plates. The rusted plates were subjected to four types of scraping treatment to obtain rusted plates with a 30 μm thick rust layer. The salt concentration of the steel plate surface was then adjusted by washing with ion-exchanged water or by using an aqueous sodium chloride solution. As a result, five types of steel plates with different surface salt concentrations (salt concentration 5±5 mg / m 2 , 30±5 mg / m 2 , 50±5 mg / m 2 , 100±30mg / m 2 , 200±30mg / m 2 The surface salinity was measured using a surface salinity meter SNA-3000 manufactured by Sanko Electronics Laboratory, and the salinity (mg / m 2 ) values ​​were adopted.

[0141] The anti-rust coating composition was spray-painted onto each test plate, and then dried at 23°C for one week to prepare test plates having an anti-rust coating film with a thickness of 60 µm.

[0142] The obtained test plates (75 mm x 150 mm) were subjected to a combined cyclic corrosion test in accordance with the Cycle A (CCT) method of the cyclic corrosion test method specified in JIS K5600-7-9:2006. Specifically, a combined cyclic corrosion test was performed for 150 cycles using a combined cyclic corrosion tester (manufactured by Suga Test Instruments, Model CCT-1). The number of rust spots that appeared after the test was evaluated. If all five types of test plates were at Level 7 or higher, the test plate had high corrosion resistance.

[0143] (Evaluation criteria) 10:0 pieces 9: Less than 10 8: 10 or more but less than 20 7: 20 or more but less than 50 6: 50 to less than 100 5: 100 or more but less than 200 4: 200 or more but less than 400 3: 400 or more but less than 600 2: 600 or more but less than 800 1:800 pieces or more

[0144] (2) Pull-off adhesion TP Giken SS400 grit-blasted steel plates were exposed to the coastal area of ​​Tamano City, Okayama Prefecture for 12 months to allow rust to form on the steel plates. Some of the rust was removed appropriately using a nonwoven abrasive (trade name "Magiclon (registered trademark)" manufactured by Sankyo Rikagaku Co., Ltd.) to prepare four types of steel plates with rust thicknesses of 30±5 μm, 50±5 μm, 100±10 μm, and 150±25 μm, respectively.

[0145] Next, the anti-rust coating composition was spray-painted onto each test plate, and then dried at 23°C for one week to prepare test plates having an anti-rust coating film with a thickness of 60 µm.

[0146] The test panels were placed in a humidity tester at 50°C and 100% RH for 7 days. The test panels were then removed and left for 24 hours. The pull-off adhesion was then measured in accordance with JIS K 5600-5-7:2014 General Test Methods for Paints - Part 5: Mechanical Properties of Coatings - Section 7: Adhesion (Pull-off Method). A level of 4 or higher on all four test panels indicates high pull-off adhesion.

[0147] (Evaluation criteria) 5: 3.0 MPa or more 4: 2.0 MPa or more and less than 3.0 MPa 3: 1.0 MPa or more, less than 2.0 MPa 2: 0.5 MPa or more and less than 1.0 MPa 1: Less than 0.5 MPa

[0148] [Table 1]

[0149] [Table 2]

[0150] [Table 3]

[0151] [Table 4]

[0152] [Table 5]

[0153] [Table 6]

[0154] [Table 7]

[0155] [Table 8]

[0156] [Table 9]

[0157] The anti-rust coating films formed using the anti-rust coating compositions of Examples 1 to 45 covered the entire rust on the steel sheet, and had anti-rust properties of level 7 or higher and pull-off adhesion of level 4 or higher. In Examples 33 to 35, a zinc compound (c-3) was added to Example 9. In this case, the residual salt content was 100±30 mg / m 2 The rust prevention properties against the rusted plates were further improved. In Example 36, zinc powder (c-3) was added to Example 9. In this case, the residual salt content was 200±30 mg / m 2 The rust prevention properties against the above rusted plates were further improved.

[0158] Comparative Examples 1 and 14 to 20 do not contain the metal sulfate (c-1). Therefore, rust conversion does not occur, and the residual salt content is 100±30 mg / m 2The rust prevention performance against the above rusted plates was level 6 or less, and the pull-off adhesion against rusted plates with a rust thickness of 50±5 μm or more was level 3 or less.

[0159] Comparative Examples 7 and 13 contained an excessive amount of metal sulfate (c-1). As a result, sufficient rust conversion occurred and high rust prevention was obtained, but the rust conversion reaction was so rapid that the pull-off adhesion to rusted plates with a rust thickness of 50±5 μm or more was level 3 or lower.

[0160] Comparative Examples 4 to 6 contain an excess amount of alkaline earth metal compound (c-2). As a result, the rate of rust conversion is reduced, and the residual salt content is 200±30 mg / m 2 The rust prevention performance against the rusted plate was level 6. In addition, because rust conversion did not progress sufficiently, the pull-off adhesion against the rusted plate with a rust thickness of 100±10 μm or more was level 3 or less.

[0161] In Comparative Example 8, the amount of alkaline earth metal compound (c-2) was small. Therefore, the speed of rust conversion could not be controlled, and a rapid rust conversion reaction occurred. As a result, the pull-off adhesion to rusted plates with a rust thickness of 100±10 μm or more was level 3 or less.

[0162] Comparative Examples 2, 9, and 11 are 2+ / SO4 2- ) is less than 0.4. Therefore, the blocking properties and cohesive strength of the anti-rust coating film are reduced. As a result, the residual salt content is 100±30mg / m 2 The rust prevention performance against the rusted plates with a thickness of 50±5 μm or more was level 6 or less, and the pull-off adhesion performance against the rusted plates with a thickness of 50±5 μm or more was level 3 or less.

[0163] Comparative Examples 3, 10, and 12 are 2+ / SO4 2- ) exceeds 2.0. Therefore, the blocking property and cohesive force of the anticorrosive coating film are reduced. As a result, in Comparative Examples 3 and 10, the residual salt content was 100±30 mg / m 2The rust prevention properties for the rusted plates with a rust thickness of 100±10 μm or more were level 6 or less, and the pull-off adhesion properties for the rusted plates with a rust thickness of 100±10 μm or more were level 3 or less. 2 The rust prevention performance against the rusted plates with a thickness of 50±5 μm or more was level 6 or less, and the pull-off adhesion performance against the rusted plates with a thickness of 50±5 μm or more was level 3 or less.

[0164] In Comparative Examples 21 and 22, the alkaline earth metal compound (c-2) was used in excess and in a ratio (M 2+ / SO4 2- ) is more than 2.0. Therefore, the rate of rust conversion is reduced, and the blocking properties and cohesive strength of the rust-preventive coating film are also reduced. As a result, in Comparative Example 21, the residual salt content was 50±5 mg / m 2 The rust prevention properties for the rusted plates with a rust thickness of 50±5 μm or more were level 6 or less, and the pull-off adhesion properties for the rusted plates with a rust thickness of 50±5 μm or more were level 3 or less. 2 The rust prevention performance against the rusted plates with a thickness of 50±5 μm or more was level 6 or less, and the pull-off adhesion performance against the rusted plates with a thickness of 50±5 μm or more was level 3 or less.

[0165] In Comparative Example 23, the pigment volume concentration was too low, making it difficult for the rust conversion reaction to occur. As a result, the residual salt content was 100±30 mg / m 2 The rust prevention effect on rusted plates with a thickness of 100±10 μm or more was level 6, and the pull-off adhesion on rusted plates with a thickness of 100±10 μm or more was level 3 or less.

[0166] In Comparative Example 24, the pigment volume concentration was too high and the cohesive strength of the anti-rust coating film was low, resulting in pull-off adhesion of level 3 or less for all rust thicknesses.

[0167] The present invention provides the following aspects. [1] an epoxy resin (a); a polyamine (b); A rust-preventive coating composition comprising: The powder (c) is A metal sulfate (c-1) with a solubility of 0.1 g or more in 100 g of water at 5°C; and an alkaline earth metal compound (c-2) which is at least one of an alkaline earth metal oxide and an alkaline earth metal hydroxide, the content of the metal sulfate (c-1) is 0.5% by mass or more and 10.0% by mass or less, based on 100% by mass of the resin solid content of the anticorrosive coating composition; the content of the alkaline earth metal compound (c-2) is 0.25% by mass or more and 10.0% by mass or less, based on 100% by mass of the resin solid content of the anticorrosive coating composition; The sulfate ions (SO4 2- ) and the number of moles of alkaline earth metal ions (M 2+ ) and the ratio of moles (M 2+ / SO4 2- ) is between 0.4 and 2.0, The anti-rust coating composition has a pigment volume concentration of 28.0% or more and 45.0% or less. [2] The anticorrosive coating composition according to [1] above, wherein the metal sulfate (c-1) comprises at least one selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, and zinc sulfate. [3] The rust-preventive coating composition according to the above [1] or [2], wherein the alkaline earth metal compound (c-2) comprises at least one selected from the group consisting of calcium oxide, calcium hydroxide, barium oxide and barium hydroxide. [4] The anticorrosive coating composition according to any one of the above [1] to [3], further comprising at least one of zinc powder and zinc compound (c-3). [5] The anti-rust coating composition according to any one of the above [1] to [4], which is for steel materials having rust on the surface. [6] The rust-preventive coating composition according to any one of the above [1] to [4], which is for steel materials having rust and salt on the surface. [7] A coated article comprising a steel material having rust on its surface and a rust-preventive coating film having a dry film thickness of 60 μm formed from the rust-preventive coating composition, is left to stand for 7 days in a humidity resistance tester at 50°C and 100% RH, and then the pull-off adhesion measured in accordance with JIS K 5600-5-7:2014 General test methods for paints - Part 5: Mechanical properties of coatings - Section 7: Adhesion (pull-off method) is 2.0 MPa or more. [8] A steel material having rust on its surface; A coated article comprising the steel material and an anti-rust coating film formed from the anti-rust coating composition of any one of the above [1] to [7]. [9] The coated article of [8] above, wherein the thickness of the rust on the surface of the steel material is 10 μm or more and 200 μm or less.

[10] The coated article according to [8] or [9] above, wherein the anti-rust coating film covers rust on the surface of the steel material.

[11] The coated article according to any one of the above [8] to

[10] , wherein the steel material further has salt on the surface.

[12] A method for producing a coated article, comprising applying any one of the anti-rust coating compositions [1] to [7] above to a steel material having rust on its surface. [Industrial Applicability]

[0168] According to the present invention, there is provided an anti-rust coating composition that can impart excellent adhesion and anti-rust properties to rusted steel materials. The anti-rust coating composition according to the present invention is particularly suitable as an undercoat for steel materials used in large structures such as plants, bridges, steel towers, and buildings.

Claims

1. an epoxy resin (a); a polyamine (b); A rust-preventive coating composition comprising: The powder (c) is a metal sulfate (c-1) having a solubility of 0.1 g or more in 100 g of water at 5°C; and an alkaline earth metal compound (c-2) which is at least one of an alkaline earth metal oxide and an alkaline earth metal hydroxide, the content of the metal sulfate (c-1) is 0.5% by mass or more and 10.0% by mass or less, based on 100% by mass of the resin solids content of the anticorrosive coating composition; the content of the alkaline earth metal compound (c-2) is 0.25% by mass or more and 10.0% by mass or less, based on 100% by mass of the resin solids content of the anticorrosive coating composition; The sulfate ions (SO ４ ２－ ) and the number of moles of alkaline earth metal ions (M ２＋ ) and the ratio of moles (M ２＋ / SO ４ ２－ ) is equal to or greater than 0.4 and equal to or less than 2.0, The anti-rust coating composition has a pigment volume concentration of 28.0% or more and 45.0% or less.

2. 2. The rust-preventive coating composition according to claim 1, wherein the metal sulfate (c-1) comprises at least one selected from the group consisting of nickel sulfate, aluminum sulfate, magnesium sulfate, and zinc sulfate.

3. 2. The rust-preventive coating composition according to claim 1, wherein the alkaline earth metal compound (c-2) comprises at least one selected from the group consisting of calcium oxide, calcium hydroxide, barium oxide, and barium hydroxide.

4. The rust-preventive coating composition according to claim 1, further comprising at least one of zinc powder and a zinc compound (c-3).

5. 2. The rust-preventive coating composition according to claim 1, which is for use on steel materials having rust on the surface.

6. 2. The rust-preventive coating composition according to claim 1, which is for use on steel materials having rust and salt on the surface.

7. The anti-rust coating composition according to claim 1, wherein a coated article comprising a steel material having rust on its surface and an anti-rust coating film having a dry film thickness of 60 μm formed from the anti-rust coating composition is left to stand for 7 days in a humidity resistance tester at 50°C x 100% RH, and then the pull-off adhesion measured in accordance with JIS K 5600-5-7:2014 General test methods for paints - Part 5: Mechanical properties of coatings - Section 7: Adhesion (pull-off method) is 2.0 MPa or more.

8. A steel material having rust on its surface; A coated article comprising: an anti-rust coating film formed on the steel material using the anti-rust coating composition according to claim 1.

9. 9. The coated article according to claim 8, wherein the thickness of the rust on the surface of the steel material is 10 μm or more and 200 μm or less.

10. The coated article according to claim 8 , wherein the anti-rust coating film covers rust on the surface of the steel material.

11. The coated article of claim 8 , wherein the steel further comprises salt on the surface.

12. A method for producing a coated article, comprising painting the anticorrosive coating composition according to claim 1 onto a steel material having rust on its surface.

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