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

Abstract

To provide an anti-rust coating composition capable of imparting excellent anti-rust properties even to steel materials on which rust or salt remains. [Solution] An anti-rust coating composition comprising an epoxy resin (a), a polyamine (b), a powder (c), and a thickener (d), wherein the powder (c) comprises a metal sulfate (c-1) having a solubility of 0.1 g or more in 100 g of water at 5°C, and a zinc compound (c-2) having a solubility of less than 0.03 g in 100 g of water at 20°C at pH 7.0 and a solubility of 0.03 g or more in 100 g of water at 20°C at pH 4.0, wherein the content of the metal sulfate (c-1) is from 0.2 to 70% by mass relative to 100 parts by mass of the resin solid content of the anti-rust coating composition, and the content of the zinc compound (c-2) is from 10 to 200% by mass relative to 100 parts by mass of the resin solid content of the anti-rust coating composition.

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] Patent Document 1 discloses a paint containing a metal sulfate and at least one metal powder selected from the group consisting of zinc and zinc alloys. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-167379 Summary of the Invention [Problem to be solved by the invention]

[0004] When repainting steel materials, the deteriorated paint film and corroded areas are first subjected to surface preparation such as scraping. Sufficient removal of rust, particularly from corroded areas, is particularly important for rust prevention management. However, it can be difficult to thoroughly remove rust from complex structural areas such as around bolts and weld intersections, or from structures at high altitudes or offshore. Therefore, there is a demand for paints that can provide high rust prevention even when applied to steel materials with residual rust.

[0005] Additionally, in areas where salt (sea salt) flies in, such as coastal areas, the salt accelerates corrosion of steel materials. Therefore, it is desirable to thoroughly remove the salt before repainting. However, removing salt from outdoor structures requires a great deal of effort. For this reason, there is a demand for paints that can provide high rust prevention even when applied to steel materials that still have salt present.

[0006] An object of the present invention is to provide an anti-rust coating composition that can impart excellent anti-rust properties to steel materials even on which rust or salt remains. [Means for solving the problem]

[0007] The present invention provides the following aspects. [1] an epoxy resin (a); a polyamine (b); Powder (c), A rust-preventive coating composition comprising: a thickener (d); 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; a zinc compound (c-2) having a solubility of less than 0.03 g in 100 g of water at 20°C and pH 7.0 and a solubility of 0.03 g or more in 100 g of water at 20°C and pH 4.0, the content of the metal sulfate (c-1) is 0.2 mass% or more and 70 mass% or less relative to 100 mass parts of the resin solid content of the anticorrosive coating composition, The content of the zinc compound (c-2) is 10% by mass or more and 200% by mass or less relative to 100 parts by mass of the resin solid content of the anticorrosive coating composition. [2] The anticorrosive coating composition of [1] above, wherein the mass ratio (c-1 / c-2) of the content of the metal sulfate (c-1) to the content of the zinc compound (c-2) is 0.08 / 99.92 to 90.00 / 10.00. [3] The anti-rust coating composition according to [1] above, which is for steel materials having rust on the surface. [4] The anti-rust coating composition according to [1] above, which is for steel materials having salt on the surface. [5] The anticorrosive coating composition according to [1] above, wherein the metal sulfate (c-1) is a salt of a polyvalent metal cation and a sulfate ion. [6] 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, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate. [7] The anticorrosive coating composition according to the above item [1], wherein the zinc compound (c-2) comprises at least one selected from the group consisting of zinc oxide, zinc hydroxide, and zinc carbonate. [8] The anticorrosive coating composition according to the above item [1], wherein the powder (c) further contains an alkaline earth metal compound (c-3) which is at least one of an alkaline earth metal oxide and an alkaline earth metal hydroxide. [9] The anticorrosive coating composition according to [8] above, wherein the content of the alkaline earth metal compound (c-3) is 0.15 mass % or more and 40 mass % or less per 100 mass parts of the resin solid content of the anticorrosive coating composition.

[10] The anticorrosive coating composition according to [8] above, wherein the alkaline earth metal compound (c-3) comprises at least one selected from the group consisting of calcium oxide, calcium hydroxide, barium oxide, and barium hydroxide.

[11] The anti-corrosion coating composition according to [1] above, wherein the viscosity measured using a rheometer at a solids concentration of 69% by mass and a temperature of 25°C is 0.1 Pa·s or more and 1.2 Pa·s or less one minute after the start of application of shear stress at a shear rate of 1000 (1 / s), and the viscosity measured using a rheometer at a shear rate of 0.1 (1 / s) one minute after the start of application of shear stress is 40 Pa·s or more and 500 Pa·s or less.

[12] A steel material having rust on its surface; A coated article comprising the steel material and an anti-rust coating film formed on the steel material from the anti-rust coating composition according to any one of the above [1] to

[11] .

[13] The coated article of

[12] above, wherein the thickness of the rust on the surface of the steel material is 10 μm or more and 200 μm or less.

[14] The coated article of

[13] above, wherein the anti-rust coating film covers the rust on the surface of the steel material.

[15] A steel material having salt on its surface; A coated article comprising the steel material and an anti-rust coating film formed on the steel material from the anti-rust coating composition according to any one of the above [1] to

[11] .

[16] A method for producing a coated article, comprising applying any one of the anti-rust coating compositions [1] to

[11] above onto a steel material having rust on its surface.

[17] A method for producing a coated article, comprising coating a steel material having salt content on its surface with any one of the anticorrosive coating compositions [1] to

[11] above. [Effects of the Invention]

[0008] According to the present invention, there is provided an anti-rust coating composition that can impart excellent anti-rust properties even to steel materials containing residual rust or salt. DETAILED DESCRIPTION OF THE INVENTION

[0009] The anticorrosive coating composition of the present disclosure comprises an epoxy resin (a), a polyamine (b), a powder (c), and a thickener (d). The powder (c) comprises a metal sulfate (c-1) that dissolves in an amount of 0.1 g or more in 100 g of water at 5° C., and a zinc compound (c-2) that dissolves in an amount of less than 0.03 g in 100 g of water at 20° C. at pH 7.0 and in an amount of 0.03 g or more in 100 g of water at 20° C. at pH 4.0.

[0010] The content of the metal sulfate (c-1) is from 0.2 to 70% by mass, based on 100 parts by mass of the resin solid content of the anticorrosive coating composition. The content of the zinc compound (c-2) is from 10 to 200% by mass, based on 100 parts by mass of the resin solid content of the anticorrosive coating composition.

[0011] The metal sulfate (c-1) dissolves in an aqueous solution, eluting metal ions and sulfate ions. Hydrogen ions are then generated due to the acidic action of the eluted sulfate ions and the hydrolysis of the metal ions. The generated hydrogen ions dissolve the zinc compound (c-2), generating zinc ions. The generated zinc ions react with chloride ions contained in airborne salt, rainwater, or rust present on the surface of the substrate, trapping the chloride ions. The reaction between the zinc ions and chloride ions generates a compound such as basic zinc chloride. This product forms a water-stable coating (hereinafter referred to as the "anti-rust layer") within the coating. This anti-rust layer provides the anti-rust effect.

[0012] Zinc compound (c-2) exhibits rust prevention effects even when used alone. This is because the zinc ions eluted from zinc compound (c-2) contribute to rust prevention. However, it is known that the content of zinc compound (c-2) is not proportional to the rust prevention effect. This is because there is a limit to the elution of zinc ions.

[0013] It has been found that the metal sulfate (c-1) promotes the elution of zinc ions from the zinc compound (c-2). That is, by combining the zinc compound (c-2) with the metal sulfate (c-1), more zinc ions can be eluted than when the zinc compound (c-2) is used alone, which promotes the formation of a rust-preventive layer and further improves rust prevention. Therefore, the rust-preventive coating composition of the present disclosure can be used on steel materials having rust or salt on the surface. It can also impart high rust prevention properties to such steel materials.

[0014] (Anti-rust paint composition) 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.

[0015] Hereinafter, the epoxy equivalent is determined based on the mass of the solid content, in accordance with JIS K 7236:2009.

[0016] The weight average molecular weight is measured by gel permeation chromatography (GPC).

[0017] The active hydrogen equivalent of the polyamine is determined based on the mass of the solid content in accordance with JIS K 7237:1995.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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).

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] Examples of the chain aliphatic polyamine include alkylene polyamine and polyalkylene polyamine. The alkylene polyamine is, for example, HN-R 1 -NH2(wherein, R 1is 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] Alkylphenol The curing agent may further include an alkylphenol, which further improves curability (especially low-temperature curability).

[0043] 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.

[0044] 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.

[0045] ·Powder (c) The powder (c) contains a rust inhibitor. By using a specific metal sulfate (c-1) in combination with a zinc compound (c-2) as the rust inhibitor, excellent rust prevention properties can be obtained as described above.

[0046] 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.

[0047] 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-2) and the alkaline earth metal compound (c-3) described below can also be determined in the same manner.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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 (St). 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.

[0052] 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.

[0053] The content of the metal sulfate (c-1) is 0.2 mass% or more and 70 mass% or less based on 100 mass parts of the resin solid content of the anticorrosive coating composition. When the content of the metal sulfate (c-1) is 0.2 mass% or more, the effect of the metal sulfate (c-1) is exerted. When the content of the metal sulfate (c-1) is 70 mass% or less, the barrier function is further improved and the coating film properties are also improved.

[0054] The content of the metal sulfate (c-1) may be 1.0 mass% or more, 2.0 mass% or more, or 4.0 mass% or more. The content of the metal sulfate (c-1) may be 40.0 mass% or less, 20.0 mass% or less, or 15.0 mass% or less.

[0055] Zinc compounds (c-2) The zinc compound (c-2) provides zinc ions to the coating film. The zinc compound (c-2) 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.

[0056] As the pH of the coated substrate changes due to corrosion, the zinc compound (c-2) gradually dissolves in the coating film and forms basic zinc chloride together with chloride ions. Zinc chloride is a dense, highly rust-preventive compound, forming a rust-preventive layer with high barrier properties. In the present disclosure, the zinc compound (c-2) is used in combination with the metal sulfate (c-1), allowing for the elution of more zinc ions, further promoting the formation of the rust-preventive layer.

[0057] The zinc compound (c-2) 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-2) is suppressed in an environment where corrosion is unlikely to progress. On the other hand, in the acidic range, the zinc compound (c-2) has a high solubility in 100 g of water at 20°C. The zinc compound (c-2) dissolves and exerts its effect as the pH decreases due to the dissolution of the metal sulfate (c-1).

[0058] Conventionally used zinc dust and zinc alloy powder dissolve quickly due to their sacrificial corrosion protection properties. This reduces the amount of zinc ions in the coating, preventing the formation of sufficient zinc chloride. In particular, when rust or salt is present on the steel surface, the sacrificial corrosion protection properties of zinc dust and zinc alloy powder are more likely to function due to the supply of water from the crystallization water contained in the rust or the dissolution (deliquescence) of the salt. As a result, the zinc in the coating is consumed for sacrificial corrosion protection rather than the formation of zinc chloride, resulting in poor rust prevention.

[0059] Examples of the zinc compound (c-2) 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. The zinc compound (c-2) does not include metallic zinc, zinc alloys, or zinc sulfate.

[0060] The zinc compound (c-2) may be white, which increases the freedom in color design of the coating film since the color of the finish coating is not limited.

[0061] The content of the zinc compound (c-2) is 10 mass% or more and 200 mass% or less based on 100 mass parts of the resin solid content of the anticorrosive coating composition. When the content of the zinc compound (c-2) is 10 mass% or more, the effect of the zinc compound (c-2) is fully exhibited. When the content of the zinc compound (c-2) is 200 mass% or less, the film-forming property is not impaired.

[0062] The content of the zinc compound (c-2) may be 15.0 mass% or more, 20.0 mass% or more, or 50.0 mass% or more. The content of the zinc compound (c-2) may be 150.0 mass% or less, 120.0 mass% or less, or 110.0 mass% or less.

[0063] The mass ratio (c-1 / c-2) of the content of the metal sulfate (c-1) to the content of the zinc compound (c-2) may be, for example, 0.08 / 99.92 to 90.00 / 10.00. This further promotes the ionization of the zinc compound (c-2), allowing for efficient production of zinc chloride. The ratio (c-1 / c-2) may be 2.50 / 97.50 to 25.00 / 75.00, or 4.00 / 96.00 to 15.00 / 85.00.

[0064] Alkaline earth metal compounds (c-3) The powder (c) may contain an alkaline earth metal compound (c-3). The alkaline earth metal compound (c-3) is at least one of an oxide and a hydroxide of an alkaline earth metal. The alkaline earth metal compound (c-3) dissolves in water and releases alkaline earth metal ions and their counter ions. The alkaline earth metal ions react with sulfate ions to form a salt that is sparingly soluble in water.

[0065] As mentioned above, sulfate ions promote the formation of an anti-corrosion layer, but if they act directly on the substrate, they can promote corrosion of the substrate. By blending alkaline earth metal compound (c-3) with metal sulfate (c-1), corrosion of the substrate caused by sulfate ions is suppressed, and the occurrence of red rust is suppressed.

[0066] The amount of alkaline earth metal compound (c-3) dissolved is not particularly limited. The amount of alkaline earth metal compound (c-3) dissolved in 100 g of water at 20°C may be 0.05 g or more. The amount of alkaline earth metal compound (c-3) 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-3) dissolved may be 5.0 g or less, or 4.0 g or less.

[0067] 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.

[0068] Specific examples of the alkaline earth metal compound (c-3) include calcium oxide, barium oxide, strontium oxide, calcium hydroxide, barium hydroxide, and strontium hydroxide. The alkaline earth metal compound (c-3) 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.

[0069] The content of the alkaline earth metal compound (c-3) is not particularly limited. The content of the alkaline earth metal compound (c-3) is, for example, 0.15 mass% or more and 40 mass% or less, based on 100 mass parts of the resin solid content of the anticorrosive coating composition. When the content of the alkaline earth metal compound (c-3) is 0.15 mass% or more, the effect of the alkaline earth metal compound (c-3) is easily exerted. As the alkaline earth metal compound (c-3) dissolves, the coating film may become alkaline. When the content of the alkaline earth metal compound (c-3) is 40 mass% or less, deterioration of the coating film due to an increase in pH is suppressed.

[0070] The content of the alkaline earth metal compound (c-3) may be 0.2 mass% or more, 0.5 mass% or more, or 1.0 mass% or more, and may be 15.0 mass% or less, or 12.0 mass% or less.

[0071] The ratio (c-1 / c-3) of the content of the metal sulfate (c-1) to the content of the alkaline earth metal compound (c-3) is not particularly limited. The ratio (c-1 / c-3) may be, for example, 4 / 96 or more and 96 / 4 or less by mass. This can further improve rust prevention. The ratio (c-1 / c-3) may be 23 / 77 or more, 33 / 67 or more, or 50 / 50 or more. The ratio (c-1 / c-3) may be 94 / 6 or less, 91 / 9 or less, or 86 / 14 or less.

[0072] 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 zinc, zinc alloy, 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.

[0073] 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.

[0074] Thickener (d) The thickener (d) adjusts the viscosity (including the high shear viscosity and low shear viscosity described below) of the anticorrosive coating composition. Thickeners (d) include thixotropic agents, thixotropic agents, rheology control agents, and viscosity modifiers.

[0075] The content of thickener (d) is appropriately set depending on the other components contained in the anticorrosive coating composition and their amounts. The content of thickener (d) may be, for example, 0.2 mass% or more and 2.5 mass% or less of the solid content of the anticorrosive coating composition. The content of thickener (d) may be 0.4 mass% or more, or 0.6 mass% or more. The content of thickener (d) may be 2.0 mass% or less, or 1.0 mass% or less.

[0076] 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.

[0077] Inorganic thickeners include, for example, finely divided silica, clay minerals, and ultrafine precipitated calcium carbonate, which form a finely dispersed colloidal structure.

[0078] 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.

[0079] Examples of organic-inorganic composite thickeners include organic bentonite and surface-treated calcium carbonate, which form a finely dispersed colloidal structure.

[0080] 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.

[0081] 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.

[0082] 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 top coat. 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% by mass or more and 60% by mass or less of the solid content of the anti-rust coating composition. The content of the white pigment may be 10% by mass or more, 15% by mass or more, or 20% by mass or more. The content of the white pigment may be 40% by mass or less, or 30% by mass or less.

[0083] · 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.

[0084] 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.

[0085] The total content of the powder (C) and various pigments is, for example, 30% or more and 60% or less in terms of pigment volume concentration (PVC). This ensures hiding power while suppressing the occurrence of coating film cracking and deterioration of adhesion. PVC is the volume percentage (%) of the total of the powder (C) and various pigments in the volume of the solid content of the anticorrosive coating composition.

[0086] 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.

[0087] ·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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.).

[0092] ·others The anticorrosive coating composition may contain other components, such as a silane coupling agent and various additives.

[0093] 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.

[0094] 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.

[0095] ·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.

[0096] 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.

[0097] Shear viscosity The anti-corrosion coating composition of the present disclosure may have a viscosity of 0.1 Pa·s or more and 1.2 Pa·s or less one minute after the start of application of shear stress at a shear rate of 1000 (1 / s) using a rheometer under conditions of a solids concentration of 69% by mass and a temperature of 25°C, or may have a viscosity of 40 Pa·s or more and 500 Pa·s or less one minute after the start of application of shear stress at a shear rate of 0.1 (1 / s).

[0098] The shear rate of 1000 (1 / s) is set based on the shear stress applied to the anti-rust paint composition during application. A viscosity of 1.2 Pa·s or less one minute after application of shear stress at a shear rate of 1000 (1 / s) (hereinafter referred to as "high shear viscosity") indicates that the anti-rust paint composition has a sufficiently low viscosity during application. This allows the anti-rust paint composition to penetrate into recesses on the steel surface. A high shear viscosity of 0.1 Pa·s or more indicates that the anti-rust paint composition has an appropriate viscosity during application. This allows the anti-rust paint composition to adhere to and remain on the protrusions on the steel surface.

[0099] The shear rate of 0.1 (1 / s) is set based on the shear stress applied to the anticorrosive coating composition during leveling after application. A viscosity of 40 Pa·s or higher one minute after the start of shear stress application at a shear rate of 0.1 (1 / s) (hereinafter referred to as "low shear viscosity") indicates that the anticorrosive coating composition has adequate viscosity during leveling. Therefore, the anticorrosive coating composition can cure while covering the protrusions on the steel surface without flowing off. A low shear viscosity of 500 Pa·s or lower indicates that the anticorrosive coating composition has a low enough viscosity to allow leveling. Therefore, the anticorrosive coating composition can produce a smooth anticorrosive coating film with improved appearance.

[0100] The anti-rust coating composition has an appropriate viscosity for both application and leveling, and therefore can cover, for example, recesses and protrusions on the surface of a steel material, thereby suppressing further rust formation and further improving the anti-rust properties.

[0101] The high shear viscosity and low shear viscosity are measured using an anticorrosive coating composition adjusted to a solids concentration of 69 mass % at a temperature of 25°C (liquid temperature 25°C ± 3°C) using a viscosity measuring device rheometer (for example, Anton Paar, product name "MCR-302") The concentration is adjusted by adding an appropriate solvent or removing the solvent already contained.

[0102] The high shear viscosity is the viscosity (Pa·s) measured 1 minute after applying shear stress to the anticorrosive coating composition after concentration adjustment at a shear rate of 1000 (1 / s). The high shear viscosity may be 0.2 Pa·s or more, or 0.40 Pa·s or more. The high shear viscosity may be 1.00 Pa·s or less, or 0.90 Pa·s or less.

[0103] The low shear viscosity is the viscosity (Pa·s) measured 1 minute after applying shear stress to the anticorrosive coating composition after concentration adjustment at a shear rate of 0.1 (1 / s). The low shear viscosity may be 70 Pa·s or more, or 100 Pa·s or more. The low shear viscosity may be 250 Pa·s or less, or 150 Pa·s or less.

[0104] The high shear viscosity and low shear viscosity can be adjusted by the thickeners mentioned above.

[0105] ·Hue Anti-rust paint compositions are usually used as primers (anti-rust). In recent years, the diversification of applications and preferences, as well as the pursuit of originality, have led to a wide variety of designs being required for the finish coating. The ability to select the design of the finish coating without being limited by the color of the anti-rust coating is one of the important points that appeal to consumers.

[0106] The L of the anti-rust coating film of 60 μm in thickness formed by the anti-rust coating composition of the present disclosure * a * b * L in color space * value, a * value and b * The value is L * ≧70, 0≦a * ≦5.0, and 0≦b * ≦5.0 may be satisfied.

[0107] The anti-rust coating film that satisfies the above conditions has a hue that can be applied to a light-colored top coat. In other words, there is a high degree of freedom in color design, and the finish coat can be designed as desired. For example, by using a white zinc compound (c-2), the hue of the anti-rust coating film can be adjusted to the above range.

[0108] The above L * value, a * value and b * The values ​​are the values ​​of the rust-preventive coating film obtained by spraying the rust-preventive coating composition onto degreased SPCC-SB (cold-rolled steel sheet with a bright finish as specified in JIS G 3141:2017) to a dry film thickness of 60 μm, and then drying it at 23°C for one week. * value, a * value and b * The value can be obtained using a spectrophotometer (for example, CR-400 manufactured by Konica Minolta, Inc.) The anticorrosive coating composition may contain a white pigment (typically, titanium oxide).

[0109] (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.

[0110] ·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.

[0111] 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.

[0112] 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).

[0113] The anti-rust coating composition having the above shear viscosity is particularly suitable for steel materials having surface irregularities due to rust. Because the anti-rust coating composition has appropriate viscosities both during application and leveling, the anti-rust coating film can cover the concave and convex portions formed by rust on the surface of the steel material, i.e., the entire rust on the surface of the steel material.

[0114] The phrase "the rust-preventive coating film covers the rust on the surface of the steel material" means that the rust is not directly visible when the coated article is viewed from above.

[0115] 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 10 μm or more, the rust-preventive coating film can be formed so as to cover the entire rust on the surface of the steel material. From the viewpoint of rust prevention, the rust thickness may be 200 μm or less. The rust thickness may be 100 μm or less, or may be 50 μm or less. The rust-preventive coating composition of the present disclosure exhibits high rust prevention properties even on steel materials having rust with a thickness of 200 μm.

[0116] 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.

[0117] 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.

[0118] A coated article according to another embodiment of the present disclosure comprises a steel material having 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. The steel material may have the above-described rust in addition to the salt. The details of the steel material are the same as those described above.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] The dry film thickness of the anti-rust coating film may be 60 μm or more, or 120 μm or more, and may be 240 μm or less, or 180 μm or less.

[0123] 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.

[0124] 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.

[0125] 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 ]

[0126] Furthermore, the thickness z (μm) of the anti-rust coating film before drying (wet film thickness) can be calculated by z=x / dt.

[0127] Other coatings Other coating films may be formed on the anticorrosive coating film, such as topcoat paints and / or functional paints.

[0128] 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.

[0129] (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 or salt on its surface.

[0130] 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.

[0131] 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]

[0132] 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.

[0133] [Production Example 1] Preparation of epoxy resin (a) 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.

[0134] 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.

[0135] [Examples 1 to 108, Comparative Examples 1 to 47] The base agent and curing agent were each prepared according to the formulation shown in Tables 1 to 13. The base agent and curing agent were mixed to prepare anti-rust coating compositions. Unless otherwise specified, the blending amounts in Tables 1 to 13 are mass ratios relative to the solid content of the anti-rust coating composition.

[0136] Details of each component shown in Tables 1 to 13 are as follows. 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

[0137] 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

[0138] 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)

[0139] Zinc compounds (c-2) 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)

[0140] Alkaline earth metal compounds (c-3) 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)

[0141] The average particle size of each type of powder (c) was 0.1 to 40 μm.

[0142] [Measurement method] (i) High-shear viscosity and low-shear viscosity The anti-rust coating composition was diluted (adjusted) using product "Solvesso 100" so that the solid content (NV) of the composition was 69.0 mass %, to obtain a sample for shear viscosity measurement. At a temperature of 25°C, a viscosity measuring device rheometer (Anton Paar, product name "MCR-302") was used to measure the viscosity (Pa·s) one minute after applying shear stress to the sample at a shear rate of 1000 (1 / s), and the viscosity (Pa·s) one minute after applying shear stress to the sample at a shear rate of 0.1 (1 / s).

[0143] (ii) 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.

[0144] (iii) 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.

[0145] [evaluation] The anticorrosive coating compositions were evaluated by the following methods, and the evaluation results are shown in Tables 1 to 13.

[0146] (1) Rust prevention A (rust prevention for rusted steel plates) 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 surface treatment to obtain rusted plates with a thickness of 30 μm. 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, seven 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 , 500±100mg / m 2 , 1000±200mg / 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.

[0147] The anti-rust coating composition was spray-painted onto each test plate, and then dried at 23°C for one week to produce coated plates having an anti-rust coating film with a thickness of 60 µm.

[0148] The resulting coated panels (75mm x 150mm) were subjected to a combined cyclic corrosion test in accordance with Cycle A (CCT) of the cyclic corrosion test method specified in JIS K5600-7-9:2006. Specifically, a 150-cycle accelerated corrosion test was performed 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 seven test panels achieved level 7 or higher, the test panel had high corrosion resistance.

[0149] (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

[0150] (2) Rust prevention B (rust prevention for steel plates containing salt) 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 develop on the steel plates. Part of the rust was removed appropriately using a nonwoven abrasive (trade name "Magiclon", manufactured by Sankyo Rikagaku Co., Ltd.) to prepare five types of steel plates with rust thicknesses of 30±2 μm, 40±5 μm, 60±5 μm, 80±5 μm, and 100±10 μm. The salt concentration on the steel plate surface was then adjusted to 50±5 mg / m using a sodium chloride aqueous solution. 2 was adjusted to.

[0151] Except for using the above steel plates, coated plates were prepared in the same manner as for Rust Prevention A, and an accelerated corrosion test and evaluation were carried out. If all five types of test plates were at level 7 or higher, they had high rust prevention properties.

[0152] (3) Hue The anti-rust coating composition was sprayed onto degreased SPCC-SB (cold-rolled steel sheet with a bright finish as specified in JIS G 3141:2017), and then dried at 23°C for one week to produce a coated sheet with an anti-rust coating film 60 μm thick. The L of the resulting painted board * a * b * L in color space * value, a * value and b * The values ​​were measured using a spectrophotometer (CR-400, manufactured by Konica Minolta, Inc.). Evaluation A means that the anticorrosive coating composition is white to pale in color, indicating a high degree of freedom in color design. Evaluation B means that the anticorrosive coating composition is colored.

[0153] (Evaluation criteria) A:L * ≧70, -5.0≦a * ,b * ≦5.0 B:L * <70, -5.0>a* ,b * 、a * ,b * >5.0

[0154]

Table 1

[0155]

Table 2

[0156]

Table 3

[0157]

Table 4

[0158]

Table 5

[0159]

Table 6

[0160]

Table 7

[0161]

Table 8

[0162]

Table 9

[0163]

Table 10

[0164] [Table 11]

[0165] [Table 12]

[0166] [Table 13]

[0167] The anti-rust coating films formed using the anti-rust coating compositions of Examples 1 to 108 covered the entire rust on the steel sheet, and both the anti-rust A and anti-rust B were at level 7 or higher. 2 High rust prevention was observed even on rusted steel plates with the above surface salt content.

[0168] Regarding the examples with a low content of zinc compound (c-2), the anti-rust coating films formed using the anti-rust coating compositions of Comparative Examples 1, 6, 36 and 41 had a zinc compound (c-2) content of 100±30 mg / m 2 The rust-preventive coating film formed using the rust-preventive coating composition of Comparative Example 11 had an anticorrosion property of 200±30 mg / m2 or less. 2 The rust prevention performance for the rusted steel plate having the above surface salt content was inferior to that of A.

[0169] Regarding the example with a high content of zinc compound (c-2), the rust-preventive coating film formed using the rust-preventive coating composition of Comparative Example 2 had a zinc compound content of 100±30 mg / m 2 The rust-preventive coating films formed using the rust-preventive coating compositions of Comparative Examples 7, 12, 37 and 42 had a surface salt concentration of 200±30 mg / m 2 The rust prevention performance against rusted steel plates with a surface salt concentration of 100 or more was inferior to that of A.

[0170] Regarding the examples in which zinc powder was used without containing the zinc compound (c-2), the rust-preventive coating films formed using the rust-preventive coating compositions of Comparative Examples 3 to 5, 38 to 40, and 43 had a coating density of 100±30 mg / m 2 The rust-preventive coating films formed using the rust-preventive coating compositions of Comparative Examples 8 to 10, 13 to 15, 30, and 44 had a surface salt concentration of 200±30 mg / m 2 In Comparative Example 45, the rust-preventive coating film formed using the rust-preventive coating composition had a surface salt concentration of 50±5 mg / m2, which was inferior to the rust-preventive coating film A. 2 The rust prevention performance for the rusted steel plate having the above surface salt content was inferior to that of A.

[0171] Comparative Examples 5, 40, and 45, which contained particularly high amounts of zinc dust, had rust thicknesses of 60±5 μm or more, Comparative Examples 4, 10, 15, 30, and 44 had rust thicknesses of 80±5 μm or more, and Comparative Examples 9, 14, and 39 had rust thicknesses of 100±10 μm or more, resulting in poor rust prevention performance (B). This is believed to be due to the paint's low shear viscosity being less than 50 Pa·s, which resulted in the paint film thickness being thin in the protruding areas of the rust. Furthermore, these examples did not meet the target color standard.

[0172] Regarding the examples containing no zinc compound (c-2) but containing an alkaline earth metal compound (c-3), Comparative Examples 16, 18 to 21, 23 to 26, 28, and 29 are 100±30 mg / m 2 The rust-preventive properties A of the rust-resistant steel sheets having a surface salt concentration of 200±30 mg / m or more were poor. 2 The rust-preventive properties of the rusted steel plates having a surface salt concentration of above 100% were poor.

[0173] Comparative Examples 31 to 35, which did not contain the metal sulfate (c-1) and contained only the zinc compound (c-2), had a concentration of 100±30 mg / m 2 The rust-preventive properties of the rusted steel plates having a surface salt concentration of above 100% were poor.

[0174] In Comparative Examples 46 and 47, which had a high content of metal sulfate (c-1), the 2The rust prevention performance of the coating was inferior to that of the coating on rusted steel plates with a surface salt concentration of 1000 or more, which was A. The rust prevention performance of the coating on steel plates with rust of 60±5 μm or more was also inferior to that of the coating on rusted steel plates with a surface salt concentration of 1000 or more .... The rust prevention performance of the coating on steel plates with rust of 60±5 μm or more

[0175] The present invention provides the following aspects. [1] an epoxy resin (a); a polyamine (b); Powder (c), A rust-preventive coating composition comprising: a thickener (d); 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; a zinc compound (c-2) having a solubility of less than 0.03 g in 100 g of water at 20°C and pH 7.0 and a solubility of 0.03 g or more in 100 g of water at 20°C and pH 4.0, the content of the metal sulfate (c-1) is 0.2 mass% or more and 70 mass% or less relative to 100 mass parts of the resin solid content of the anticorrosive coating composition, The content of the zinc compound (c-2) is 10% by mass or more and 200% by mass or less relative to 100 parts by mass of the resin solid content of the anticorrosive coating composition. [2] The anticorrosive coating composition of [1] above, wherein the mass ratio (c-1 / c-2) of the content of the metal sulfate (c-1) to the content of the zinc compound (c-2) is 0.08 / 99.92 to 90.00 / 10.00. [3] The anti-rust coating composition according to [1] or [2] above, which is for steel materials having rust on the surface. [4] The anti-rust coating composition according to any one of the above [1] to [3], which is for steel materials having salt content on the surface. [5] The anticorrosive coating composition of any one of the above [1] to [4], wherein the metal sulfate (c-1) is a salt of a polyvalent metal cation and a sulfate ion. [6] The anticorrosive coating composition of any one of [1] to [5] above, wherein the metal sulfate (c-1) comprises at least one selected from the group consisting of 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. [7] The anticorrosive coating composition of any one of the above [1] to [6], wherein the zinc compound (c-2) comprises at least one selected from the group consisting of zinc oxide, zinc hydroxide, and zinc carbonate. [8] The anticorrosive coating composition of any one of the above [1] to [7], wherein the powder (c) further contains an alkaline earth metal compound (c-3) which is at least one of an alkaline earth metal oxide and an alkaline earth metal hydroxide. [9] The anticorrosive coating composition according to [8] above, wherein the content of the alkaline earth metal compound (c-3) is 0.15 mass % or more and 40 mass % or less per 100 mass parts of the resin solid content of the anticorrosive coating composition.

[10] The anticorrosive coating composition according to the above [8] or [9], wherein the alkaline earth metal compound (c-3) comprises at least one selected from the group consisting of calcium oxide, calcium hydroxide, barium oxide, and barium hydroxide.

[11] The anti-corrosion coating composition of any one of [1] to

[10] above, which has a viscosity of 0.1 Pa s or more and 1.2 Pa s or less one minute after the start of application of shear stress at a shear rate of 1000 (1 / s) using a viscosity measuring device rheometer under conditions of a solids concentration of 69 mass% and a temperature of 25°C, and a viscosity of 40 Pa s or more and 500 Pa s or less one minute after the start of application of shear stress at a shear rate of 0.1 (1 / s).

[12] A steel material having rust on its surface; A coated article comprising the steel material and an anti-rust coating film formed on the steel material from the anti-rust coating composition according to any one of the above [1] to

[11] .

[13] The coated article of

[12] above, wherein the thickness of the rust on the surface of the steel material is 10 μm or more and 200 μm or less.

[14] The coated article according to

[12] or

[13] above, wherein the anti-rust coating film covers the rust on the surface of the steel material.

[15] A steel material having salt on its surface; A coated article comprising the steel material and an anti-rust coating film formed on the steel material from the anti-rust coating composition according to any one of the above [1] to

[11] .

[16] A method for producing a coated article, comprising applying any one of the anti-rust coating compositions [1] to

[11] above onto a steel material having rust on its surface.

[17] A method for producing a coated article, comprising coating a steel material having salt content on its surface with any one of the anticorrosive coating compositions [1] to

[11] above. [Industrial Applicability]

[0176] According to the present invention, there is provided an anti-rust coating composition that can impart excellent anti-rust properties to steel materials even on which rust or salt remains. 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); Powder (c), 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; a zinc compound (c-2) having a solubility of less than 0.03 g in 100 g of water at 20°C and pH 7.0 and a solubility of 0.03 g or more in 100 g of water at 20°C and pH 4.0, the content of the metal sulfate (c-1) is 0.2 mass% or more and 70 mass% or less relative to 100 mass parts of the resin solid content of the anticorrosive coating composition, The content of the zinc compound (c-2) is 10% by mass or more and 200% by mass or less relative to 100 parts by mass of the resin solid content of the rust-preventive coating composition.

2. 2. The rust-preventive coating composition according to claim 1, wherein the mass-based ratio (c-1 / c-2) of the content of the metal sulfate (c-1) to the content of the zinc compound (c-2) is 0.08 / 99.92 to 90.00 / 10.

00.

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

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

5. 2. The rust-preventive coating composition according to claim 1, wherein the metal sulfate (c-1) is a salt of a polyvalent metal cation and a sulfate ion.

6. The anticorrosive 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, zinc sulfate, cobalt sulfate, chromium sulfate, copper sulfate, titanium sulfate, tin sulfate, zirconium sulfate, vanadium sulfate, and manganese sulfate.

7. 2. The rust-preventive coating composition according to claim 1, wherein the zinc compound (c-2) comprises at least one selected from the group consisting of zinc oxide, zinc hydroxide, and zinc carbonate.

8. 2. The rust-preventive coating composition according to claim 1, wherein the powder (c) further contains an alkaline earth metal compound (c-3) which is at least one of an alkaline earth metal oxide and an alkaline earth metal hydroxide.

9. 9. The rust-preventive coating composition according to claim 8, wherein the content of the alkaline earth metal compound (c-3) is 0.15 mass% or more and 40 mass% or less relative to 100 mass parts of the resin solids content of the rust-preventive coating composition.

10. The rust-preventive coating composition according to claim 8, wherein the alkaline earth metal compound (c-3) comprises at least one selected from the group consisting of calcium oxide, calcium hydroxide, barium oxide, and barium hydroxide.

11. 2. The rust-preventive coating composition according to claim 1, wherein the viscosity measured at a solids concentration of 69% by mass and a temperature of 25°C using a viscosity measuring device rheometer is 0.1 Pa s or more and 1.2 Pa s or less one minute after the start of application of shear stress at a shear rate of 1000 (1 / s), and the viscosity measured at a shear rate of 0.1 (1 / s) one minute after the start of application of shear stress is 40 Pa s or more and 500 Pa s or less.

12. 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 any one of claims 1 to 11.

13. The coated article according to claim 12, wherein the thickness of the rust on the surface of the steel material is 10 μm or more and 200 μm or less.

14. The coated article of claim 13 , wherein the anti-rust coating covers the rust on the surface of the steel material.

15. A steel material having salt 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 any one of claims 1 to 11.

16. A method for producing a coated article, comprising applying the anticorrosive coating composition according to any one of claims 1 to 11 to a steel material having rust on its surface.

17. A method for producing a coated article, comprising applying the anticorrosive coating composition according to any one of claims 1 to 11 to a steel material having salt on its surface.

Images