Anticorrosive coating composition

Abstract

This anticorrosive coating composition comprises a main agent (I) and a curing agent (II), wherein: the main agent (I) contains an epoxy resin (a); the epoxy resin (a) contains at least one of a bisphenol A epoxy resin (a-11) and a novolac epoxy resin (a-12) each having a weight average molecular weight of 6,000-12,000; the curing agent (II) contains a polyamine (b) and an alkylphenol (c); the polyamine (b) contains an alicyclic polyamine (b-1) having a cyclic aliphatic hydrocarbon group to which an amino group is bonded and contains a non-alicyclic polyamine (b-2) having no cyclic aliphatic hydrocarbon group to which an amino group is bonded; at least one of the main agent (I) and the curing agent (II) includes a vinyl-based defoaming agent (d) that has a constituent unit derived from at least one monomer selected from the group consisting of alkyl (meth)acrylates, alkyl vinyl ethers, and olefins and that has a number average molecular weight of 30,000-100,000 or 300,000-2,000,000; the content of the alicyclic polyamine (b-1) is 30%-80% by mass of the solid content of the curing agent (II); the content of the non-alicyclic polyamine (b-2) is 2%-45% by mass of the solid content of the curing agent (II); the content of the alkylphenol (c) is 5%-60% by mass of the solid content of the curing agent (II); and the content of the vinyl-based defoaming agent (d) is 0.005-3 parts by mass with respect to 100 parts by mass of the anticorrosive coating composition.

Description

Anticorrosion coating composition

[0001] The present invention relates to an anticorrosion coating composition.

[0002] Patent Document 1 discloses a two-component mixed coating composition paint containing an epoxy resin (a) having a weight-average molecular weight of 6,500 to 10,000, an alicyclic polyamine (b-1), a polyamine (b-2) not containing an alicyclic polyamine, and an alkylphenol (b-3).

[0003] Patent No. 6832122

[0004] The coating composition described in Patent Document 1 does not have sufficient corrosion resistance.

[0005] An object of the present invention is to provide an anticorrosion coating composition having excellent anticorrosion properties.

[0006] The present invention provides the following aspects: [1] An anticorrosion coating composition comprising a base agent (I) and a curing agent (II), wherein the base agent (I) comprises an epoxy resin (a), the epoxy resin (a) comprises at least one of a bisphenol A epoxy resin (a-11) and a novolac epoxy resin (a-12) having a weight average molecular weight of 6,000 or more and 12,000 or less, the curing agent (II) comprises a polyamine (b) and an alkylphenol (c), the polyamine (b) comprises an alicyclic polyamine (b-1) having a cyclic aliphatic hydrocarbon group to which an amino group is bonded and a non-alicyclic polyamine (b-2) not having a cyclic aliphatic hydrocarbon group to which an amino group is bonded, an alkylphenol (c) content of the curing agent (II) containing a vinyl antifoaming agent (d) having a number average molecular weight of 30,000 to 100,000, or 300,000 to 2,000,000; and an alkylphenol (c) content of the curing agent (II) containing a vinyl antifoaming agent (d) having a number average molecular weight of 30,000 to 100,000, or 300,000 to 2,000,000. The anticorrosion coating composition includes: at least one of the main agent (I) and the curing agent (II) containing a structural unit derived from at least one monomer selected from the group consisting of alkyl(meth)acrylate, alkyl vinyl ether, and olefin; the vinyl antifoaming agent (d) having a number average molecular weight of 30,000 to 100,000, or 300,000 to 2,000,000; the alicyclic polyamine (b-1) is present in an amount of 30 to 80% by mass of the solid content of the curing agent (II); the non-alicyclic polyamine (b-2) is present in an amount of 2 to 45% by mass of the solid content of the curing agent (II); the alkylphenol (c) is present in an amount of 5 to 60% by mass of the solid content of the curing agent (II); and the vinyl antifoaming agent (d) is present in an amount of 0.005 to 3 parts by mass, relative to 100 parts by mass of the anticorrosion coating composition. [2] The resistance value of a 60 μm thick coating film formed from the anticorrosion coating composition after immersion in ion-exchanged water at 35° C. for 24 hours is 1.0×10 ９ Ω cm ２ [3] The anticorrosion coating composition according to [1] above, wherein the volume resistivity of a coating film formed from the anticorrosion coating composition after immersion in ion-exchanged water at 35°C for 24 hours is 1.7 x 10 or more. ８The anticorrosion coating composition of [1] or [2] above, wherein the non-alicyclic polyamine (b-2) comprises at least one selected from the group consisting of aliphatic polyamines, polyamines having an aromatic hydrocarbon group, and polyamines having a heterocycle. [5] The anticorrosion coating composition of any of [1] to [4] above, wherein the main component (I) further comprises a silane coupling agent (e) having at least one of a trimethoxysilyl group and a triethoxysilyl group. [6] The anticorrosion coating composition of any of [1] to [5] above, further comprising a weak solvent (f). [7] The anticorrosion coating composition of any of [1] to [6] above, wherein the main component (I) further comprises a pigment (g), and the pigment volume concentration of the main component (I) is 25% by volume or more and 55% by volume or less. [8] A coated article comprising: a metal substrate; and a primer coating film formed on the substrate using the anticorrosion coating composition according to any one of [1] to [7] above.

[0007] According to the present invention, there is provided an anticorrosion coating composition having excellent anticorrosion properties.

[0008] 1 is an explanatory diagram showing an overview of an apparatus for measuring resistance values, and FIG. 2 is a graph showing changes in applied voltage when measuring resistance values.

[0009] [Anti-corrosion coating composition] The anti-corrosion coating composition of the present disclosure is a two-component type comprising a base agent containing an epoxy resin (a) and a curing agent containing a polyamine (b) and an alkylphenol (c). The vinyl anti-foaming agent (d) may be contained in the base agent, the curing agent, or both. The vinyl anti-foaming agent (d) may be contained in the base agent.

[0010] One of the reasons for the decline in corrosion resistance is the penetration of corrosion factors (e.g., water, oxygen, chloride ions) into the coating film. If the ability to block corrosion factors (blocking ability) is improved, the corrosion resistance will increase and the electrical resistance of the coating film will also increase.

[0011] In a curing system of epoxy resin and polyamine, viscosity tends to increase as the curing reaction progresses, restricting molecular motion within the coating film. As a result, the curing reaction becomes difficult to proceed beyond a certain point, and unreacted amino groups and low-molecular-weight components tend to remain. These components reduce barrier properties and corrosion resistance.

[0012] In the present disclosure, an epoxy resin (a) having a relatively high molecular weight and easily forming a planar structure is used. In addition, an alicyclic polyamine (b-1) also easily forming a planar structure is used as a curing agent. This results in a dense coating film and improved barrier properties.

[0013] Furthermore, a specific vinyl-based defoaming agent (d) is used. By using the specific vinyl-based defoaming agent (d) in a system containing the above-mentioned specific epoxy resin (a), a defoaming effect is particularly exhibited, and a denser coating film is formed.

[0014] The defoaming effect is thought to be achieved through the following mechanism. First, the defoaming agent adsorbs to the generated bubbles, causing them to aggregate together. The aggregated bubbles rise to the surface of the coating film due to buoyancy. Once the bubbles rise to the surface of the coating film, the defoaming agent penetrates into the foam film. The foam film loses its elasticity as the defoaming agent penetrates, causing the film to stretch and eventually break.

[0015] The vinyl-based defoaming agent (d) has a number-average molecular weight of 30,000 or more and 100,000 or less, or 300,000 or more and 2,000,000 or less. Therefore, the vinyl-based defoaming agent (d) is not easily compatible with the epoxy resin (a) having a weight-average molecular weight of 6,000 or more and 12,000 or less. As a result, the vinyl-based defoaming agent (d) can easily adsorb to the generated bubbles and fully exert its effect. In addition, vinyl-based defoaming agents are known to have high surface tension and excellent foam-breaking properties. As a result, the coating film obtained by the anticorrosion coating composition of the present disclosure is dense and has high barrier properties.

[0016] Hereinafter, the epoxy equivalent is determined based on the mass of the solid content in accordance with JIS K 7236:2001.

[0017] The weight average molecular weight is measured by gel permeation chromatography (GPC).

[0018] The active hydrogen equivalent of the polyamine is determined based on the mass of the solid content in accordance with JIS K 7237:1995.

[0019] The solid content of the anticorrosion coating composition is the total content of the anticorrosion coating composition excluding volatile components (typically, solvents). The solid content concentration of the anticorrosion coating composition can be calculated from the residue when the anticorrosion coating composition is heated at 140°C in accordance with JIS K 5601-1-2 Heat Residue Measurement Method.

[0020] The resin solid content of the anticorrosion coating composition is the solid content of the epoxy resin (a), polyamine (b) and other resin components contained in the anticorrosion coating composition.

[0021] Main Component (I) The main component (I) contains an epoxy resin (a).

[0022] Epoxy resin (a) The epoxy resin (a) is a coating film-forming component. The epoxy resin (a) undergoes a crosslinking reaction with the polyamine (b) to form a cured coating film.

[0023] The epoxy resin (a) contains at least one of a bisphenol A epoxy resin (a-11) and a novolac epoxy resin (a-12) having a weight-average molecular weight of 6,000 or more and 12,000 or less (hereinafter, these may be collectively referred to as the specific epoxy resin (a-1)). The specific epoxy resin (a-1) improves the barrier properties of the coating film. The specific epoxy resin (a-1) further improves the curability and adhesion of the coating film to metal substrates. From the viewpoints of moisture resistance and toughness, the specific epoxy resin (a-1) may be a novolac epoxy resin (a-12).

[0024] The weight average molecular weight of the specific epoxy resin (a-1) may be 6,500 or more, or may be 8,500 or more. The weight average molecular weight of the specific epoxy resin (a-1) may be 11,000 or less, or may be 10,000 or less.

[0025] The bisphenol A epoxy resin (a-11) is typically obtained by condensing a halogen-substituted bisphenol A with epichlorohydrin or β-methylepihalohydrin. The bisphenol A epoxy resin may be modified.

[0026] Examples of the novolac epoxy resin (a-12) include phenol novolac, cresol novolac, and novolac of bisphenol A. The novolac epoxy resin may be modified.

[0027] The solid content of the specific epoxy resin (a-1) is, for example, 15% by mass or more and 60% by mass or less of the solid content of the anticorrosion coating composition. When the content of the specific epoxy resin (a-1) is 15% by mass or more, curability can be improved. When the content of the specific epoxy resin (a-1) is 60% by mass or less, the relative proportion of pigment in the coating film increases, thereby improving hiding power. The content of the specific epoxy resin (a-1) may be 20% by mass or more, or may be 23% by mass or more. The content of the specific epoxy resin (a-1) may be 50% by mass or less, or may be 40% by mass or less.

[0028] The mass proportion of the specific epoxy resin (a-1) in the entire epoxy resin (a) is, for example, 60% by mass or more and 100% by mass or less. This makes it easier for the specific epoxy resin (a-1) to exert its effects. The above proportion of the specific epoxy resin (a-1) may be 70% by mass or more, or 80% by mass or more. The above proportion of the specific epoxy resin (a-1) may be 100% by mass, 95% by mass or less, or 90% by mass or less.

[0029] The epoxy equivalent of the specific epoxy resin (a-1) may be 1000 g / eq or more and 3500 g / eq or less, in order to enhance curability at low temperatures (e.g., 5°C or less). The epoxy equivalent of the specific epoxy resin (a-1) may be 1010 g / eq or more. In particular, in order to enhance curability at low temperatures (e.g., 5°C or less), the epoxy equivalent of the modified epoxy resin (a-1) may be 3000 g / eq or less, 2500 g / eq or less, 2000 g / eq or less, 1500 g / eq or less, or 1200 g / eq or less.

[0030] Commercially available bisphenol A epoxy resins (a-11) include, for example, the trade name "jER1007" (bisphenol A epoxy resin, weight average molecular weight 10,000, epoxy equivalent 1975 g / eq, manufactured by Mitsubishi Chemical Corporation) and the trade name "EPICLON 1040-70X" (bisphenol A epoxy resin, epoxy equivalent 1300 g / eq, manufactured by DIC Corporation). Commercially available novolac epoxy resins (a-12) include, for example, the trade name "EPICLON 5970-60" (phenol novolac epoxy resin, weight average molecular weight 9500, epoxy equivalent 1000 g / eq or more, manufactured by DIC Corporation).

[0031] The epoxy resin (a) may contain an epoxy resin (a-2) other than the specific epoxy resin (a-1). The other epoxy resin (a-2) is a novolac epoxy resin having a weight-average molecular weight of less than 6,000 or more than 12,000, a bisphenol A epoxy resin having a weight-average molecular weight of less than 6,000 or more than 12,000, or an epoxy resin other than a novolac epoxy resin or a bisphenol A epoxy resin.

[0032] Examples of epoxy resins other than novolac epoxy resins and bisphenol A epoxy resins include bisphenol epoxy resins other than bisphenol A, aromatic epoxy resins such as biphenyl and naphthalene types, and aliphatic epoxy resins such as dicyclopentadiene types and glycidyl ethers of polyhydric alcohols. These may be used alone or in combination of two or more.

[0033] Examples of biphenyl, naphthalene, and dicyclopentadiene types include resins in which one or more glycidyl ether groups are substituted at any position of biphenyl, naphthalene, or dicyclopentadiene. Examples of bisphenol-type epoxy resins other than bisphenol A type include bisphenol F, bisphenol S, bisphenol AD, diglycidyl ethers of alkylene oxide adducts of these bisphenol-type epoxy resins, and hydrogenated bisphenol types in which hydrogen is added to these bisphenol-type epoxy resins. These may be used alone or in combination of two or more.

[0034] Curing Agent (II) The curing agent (II) includes a polyamine (b) and an alkylphenol (c).

[0035] Polyamine (b) Polyamine (b) is a curing component. Polyamine (b) undergoes a crosslinking reaction with epoxy resin (a) to form a cured coating film.

[0036] The polyamine (b) includes an alicyclic polyamine (b-1) having a cyclic aliphatic hydrocarbon group to which an amino group is bonded, and a non-alicyclic polyamine (b-2) having no cyclic aliphatic hydrocarbon group to which an amino group is bonded. When the alicyclic polyamine (b-1) and the non-alicyclic polyamine (b-2) are used in combination, dissolution and lifting of the primer coating film formed from the corrosion-resistant coating composition is easily suppressed when another coating film is laminated on the primer coating film.

[0037] 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.

[0038] 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, curing properties can be improved, particularly at low temperatures. When the active hydrogen equivalent of the alicyclic polyamine (b-1) is 150 g / eq or less, blocking properties can be improved. The active hydrogen equivalent of the alicyclic polyamine (b-1) may be 33 g / eq or more. The active hydrogen equivalent of the alicyclic polyamine (b-1) may be 100 g / eq or less, or may be 50 g / eq or less.

[0039] 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).

[0040] Examples of the chain aliphatic polyamine include alkylene polyamine and polyalkylene polyamine. ２ N-R １ -NH ２ (In the formula, 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.

[0041] Examples of the chain aliphatic polyamines include tetra(aminomethyl)methane, tetrakis(2-aminoethylaminomethyl)methane, 1,3-bis(2'-aminoethylamino)propane, triethylene-bis(trimethylene)hexamine, bis(3-aminoethyl)amine, bishexamethylenetriamine [H ２ N (CH ２ ) ６ NH (CH ２ ) ６ NH ２ These may be used alone or in combination of two or more.

[0042] 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'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone, 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.

[0043] Examples of heterocyclic polyamines include N-methylpiperazine [CH ３ -N(CH ２ CH ２ ) ２ NH], morpholine [HN(CH ２ CH ２ ) 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.

[0044] The active hydrogen equivalent of the non-alicyclic polyamine (b-2) is, for example, 20 g / eq or more and 550 g / eq or less. The active hydrogen equivalent of the non-alicyclic polyamine (b-2) may be 25 g / eq or more, or 30 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.

[0045] The solid content of the alicyclic polyamine (b-1) is, for example, 30% by mass or more and 80% by mass or less of the solid content of the curing agent (II). When the content of the alicyclic polyamine (b-1) is 30% by mass or more, curability and recoatability, particularly at low temperatures, can be improved. When the content of the alicyclic polyamine (b-1) is 80% by mass or less, the tackiness of the resulting coating film can be reduced and the traction can be improved. The content of the alicyclic polyamine (b-1) may be 35% by mass or more, 40% by mass or more, or 50% by mass or more. The content of the alicyclic polyamine (b-1) may be 70% by mass or less, or 60% by mass or less.

[0046] Recoatability is a performance evaluated with reference to JIS K 5551:2018 7.10, and refers to the performance of having low solubility of the primer coating film and no hindrance to the workability of the topcoat coating when a topcoat is applied to a primer coating film formed using the corrosion-resistant coating composition according to the present disclosure. Step-inability refers to the performance of having little shoe marks left on the coating film and little peeling of the coating film when a worker walks on the coating film.

[0047] The solid content of the non-alicyclic polyamine (b-2) is, for example, 2% by mass or more and 45% by mass or less of the solid content of the curing agent (II). When the content of the non-alicyclic polyamine (b-2) is within the above range, the tackiness of the resulting coating film at low temperatures can be reduced, and the treadability can be improved. The content of the non-alicyclic polyamine (b-2) may be 5% by mass or more, 6% by mass or more, or 7% by mass or more. The content of the non-alicyclic polyamine (b-2) may be 30% by mass or less, 20% by mass or less, or 15% by mass or less.

[0048] The ratio (active hydrogen group amount / epoxy group amount) of the total amount of epoxy groups contained in the epoxy resin (a) to the total amount of active hydrogen groups contained in the polyamine (b) is, for example, 0.8 or more and 1.2 or less. When the ratio (active hydrogen group amount / epoxy group amount) is 0.8 or more, curability can be improved. When the ratio (active hydrogen group amount / epoxy group amount) is 1.2 or less, an excessive increase in reaction sites is suppressed, thereby improving the impact resistance of the primer coating film. The ratio (active hydrogen group amount / epoxy group amount) may be 0.85 or more, or may be 0.90 or more. The ratio (active hydrogen group amount / epoxy group amount) may be 1.15 or less, or may be 1.10 or less.

[0049] The amount of active hydrogen groups is obtained by dividing the solid content mass (g) of polyamine (b) by the active hydrogen equivalent (g / eq) (solid content mass (g) / active hydrogen equivalent (g / eq)). When multiple types of polyamine (b) are blended, the mass ratio (%) of each polyamine to the total polyamine (b) is calculated by multiplying the solid content mass (g) of each polyamine by the active hydrogen equivalent (g / eq), and the sum of these products is the amount of active hydrogen groups.

[0050] The amount of epoxy groups is obtained by dividing the solid content mass (g) of the epoxy resin (a) by the epoxy equivalent (g / eq) (solid content mass (g) / epoxy equivalent (g / eq)). When multiple types of epoxy resins (a) are blended, the mass percentage (%) of each epoxy resin in the total epoxy resin (a) is multiplied by the value obtained by dividing the solid content mass (g) of that epoxy resin by the epoxy equivalent (g / eq). The sum of these products is the amount of epoxy groups.

[0051] Alkylphenol (c) The curing agent further contains an alkylphenol (c), which further improves curability (particularly low-temperature curability).

[0052] Examples of the alkylphenol (c) include monohydric phenols such as methylphenol (o-, m-, p-cresol), ethylphenol, butylphenol, tert-butylphenol, octylphenol, nonylphenol, dodecylphenol, and dinonylphenol. The number of carbon atoms in the alkyl group of the alkylphenol (c) is, for example, 1 to 10. The number of carbon atoms may be 5 or less.

[0053] The solid content of the alkylphenol (c) is 5% by mass or more and 60% by mass or less of the solid content of the curing agent (II). The content of the alkylphenol (c) may be 15% by mass or more, 20% by mass or more, or 30% by mass or more. The content of the alkylphenol (c) may be 55% by mass or less, or 53% by mass or less.

[0054] Vinyl-based defoaming agent (d) exhibits a defoaming effect particularly in the curing system of a specific epoxy resin (a) and a specific polyamine (b). The vinyl-based defoaming agent (d) forms a denser coating film and improves barrier properties.

[0055] The vinyl-based defoaming agent (d) has a structural unit derived from at least one monomer selected from the group consisting of alkyl (meth)acrylate, alkyl vinyl ether, and olefin, and has a number average molecular weight of 30,000 or more and 100,000 or less, or 300,000 or more and 2,000,000 or less.

[0056] The alkyl(meth)acrylate is represented by the following general formula: ２ =CH(R １ )-C(=O)-OR ２ (In the formula, R １ is hydrogen or a methyl group, and R ２ is an alkyl group having 1 to 24 carbon atoms.

[0057] R ２R may be linear, branched, or cyclic. ２ Some of the hydrogen atoms in R may be substituted with halogen (typically fluorine or chlorine). ２ The number of carbon atoms in R may be 2 or more, 4 or more, 6 or more, or 10 or more. ２ may have 18 or less carbon atoms.

[0058] Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl methacrylate, phenyl acrylate, isobornyl (meth)acrylate, cyclohexyl methacrylate, t-butylcyclohexyl (meth)acrylate, dicyclopentadienyl (meth)acrylate, dihydrodicyclopentadienyl (meth)acrylate, octadecyl (meth)acrylate, decyl (meth)acrylate, and dodecyl (meth)acrylate. These may be used alone or in combination of two or more.

[0059] The alkyl vinyl ether is represented by the following general formula: ２ =CH(R ３ )-O-R ４ (In the formula, R ３ is hydrogen or a methyl group, and R ４ is an alkyl group having 1 to 24 carbon atoms.

[0060] R ４ R may be linear, branched, or cyclic. ４ Some of the hydrogen atoms in R may be substituted with halogen (typically fluorine or chlorine). ４ The number of carbon atoms in R may be 2 or more, 4 or more, 6 or more, or 10 or more. ４ may have 18 or less carbon atoms.

[0061] Examples of alkyl vinyl ethers include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, 2-ethylhexyl vinyl ether, decyl vinyl ether, and dodecyl vinyl ether. These may be used alone or in combination of two or more.

[0062] The olefin has the following general formula: CH(R ５ )=CH(R ６ ) (wherein, R ５ is hydrogen or an alkyl group having 1 to 24 carbon atoms, and R ６ is an alkyl group having 1 to 24 carbon atoms.

[0063] R is an alkyl group ５ may be linear, branched, or cyclic. ５ R may be saturated or unsaturated. ５ Some of the hydrogen atoms in R may be substituted with halogen (typically fluorine or chlorine). ５ The number of carbon atoms in R may be 2 or more. ５ may have 20 or less carbon atoms, or may have 10 or less carbon atoms.

[0064] R ６ R may be linear, branched, or cyclic. ６ R may be saturated or unsaturated. ６ Some of the hydrogen atoms in R may be substituted with halogen (typically fluorine or chlorine). ６ The number of carbon atoms in R may be 2 or more. ６ may have 20 or less carbon atoms, or may have 10 or less carbon atoms.

[0065] Examples of olefins include ethylene, propylene, butene, 3-methyl-1-butene, 3-methyl-1-heptene, octene, decene, octadecene, nonadecene, icosene, henicosene, butadiene, pentadiene, and hexadiene. These may be used alone or in combination of two or more.

[0066] The vinyl antifoaming agent (d) may be a homopolymer of one selected from the group consisting of alkyl (meth)acrylates, alkyl vinyl ethers, and olefins, a copolymer of at least two monomers selected from the above group, or a copolymer of at least one monomer selected from the above group with another monomer. The vinyl antifoaming agent (d) may be a homopolymer of one selected from the group consisting of alkyl (meth)acrylates, alkyl vinyl ethers, and olefins.

[0067] The number average molecular weight of the vinyl-based defoaming agent (d) is 30,000 or more and 100,000 or less, or 300,000 or more and 2,000,000 or less. The number average molecular weight of the vinyl-based defoaming agent (d-1) of 30,000 or more and 100,000 or less may be 40,000 or more, or 60,000 or more. The number average molecular weight of the vinyl-based defoaming agent (d-1) may be 90,000 or less, or 70,000 or less. The number average molecular weight of the vinyl-based defoaming agent (d-2) of 300,000 or more and 2,000,000 or less may be 500,000 or more, or 1,000,000 or more. The number average molecular weight of the vinyl-based defoaming agent (d-2) may be 1,800,000 or less, or 1,500,000 or less.

[0068] The vinyl-based defoaming agent (d-1) and the vinyl-based defoaming agent (d-2) may be used alone or in combination. The vinyl-based defoaming agent (d-1) and the vinyl-based defoaming agent (d-2) may be used alone or in combination.

[0069] The content of the vinyl antifoaming agent (d) is 0.005 parts by mass or more and 3 parts by mass or less per 100 parts by mass of the anticorrosion coating composition. When the content of the vinyl antifoaming agent (d) is 0.005 parts by mass or more, sufficient defoaming function is exhibited even at low temperatures. When the content of the vinyl antifoaming agent (d) is 3 parts by mass or less, the vinyl antifoaming agent (d) can be compatible with the anticorrosion coating composition to the extent that cissing does not occur. The content of the vinyl antifoaming agent (d) may be 0.05 parts by mass or more, or may be 0.1 parts by mass or more. The content of the vinyl antifoaming agent (d) may be 1.5 parts by mass or less, or may be 0.5 parts by mass or less.

[0070] Pigment The anticorrosion coating composition may contain a pigment. Examples of pigments include, without limitation, pigments that are typically incorporated into coating compositions. Examples of pigments include extender pigments, coloring pigments, and anticorrosive pigments. These may be used alone or in combination of two or more.

[0071] Extender pigments include, for example, talc, clay, calcium carbonate, magnesium carbonate, barium sulfate, silicic acid, silicates, aluminum oxide hydrate, calcium sulfate, gypsum, micaceous iron oxide (MIO), glass flake, 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.

[0072] Coloring Pigments Examples of coloring pigments include titanium oxide, carbon black, white lead, graphite, zinc sulfide, zinc oxide (zinc white), 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 coloring pigment is not particularly limited.

[0073] Anti-rust pigments Examples of anti-rust pigments include phosphate compounds (such as aluminum polyphosphate), molybdate compounds (such as calcium molybdate), zinc salt compounds (such as zinc sulfate), alkaline earth metal salt compounds (such as calcium hydroxide), and bismuth compounds (such as bismuth oxide). These may be used alone or in combination of two or more. The content of the anti-rust pigment is not particularly limited.

[0074] The total content of the various pigments is, for example, 25% by volume or more and 55% by volume or less in terms of pigment volume concentration (PVC). This ensures hiding power while suppressing the occurrence of coating cracks and deterioration of adhesion. The PVC is the volume percentage (%) of the total of the various pigments relative to the total volume of the total resin solids and the various pigments in the anticorrosion coating composition. The PVC of the main component may be 30% by volume or more, or 35% by volume or more. The PVC of the main component may be 50% by volume or less, or 45% by volume or less.

[0075] Other Resins The anticorrosive coating composition may contain resins other than the epoxy resin (a) and the polyamine (b). Examples of other resins include xylene resins, acrylic resins, and polyester resins. These may be used alone or in combination of two or more.

[0076] Weak Solvent (f) The anticorrosion coating composition may contain a weak solvent (f). The weak solvent improves low-temperature curing properties, recoatability, and shrinkage resistance.

[0077] Shrinkage resistance refers to the ability to inhibit shrinkage or lifting of an existing coating film when the anticorrosive coating composition according to the present disclosure is applied to the existing coating film.

[0078] The content of the weak solvent (f) is, for example, 10% by mass or more and 60% by mass or less of the total mass of the anticorrosion coating composition. The content of the weak solvent (f) may be 20% by mass or more, or 30% by mass or more. The content of the weak solvent (f) may be 50% by mass or less, or 40% by mass or less.

[0079] The weak solvent (f) is an aliphatic hydrocarbon compound. Examples of the weak solvent (f) 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 may be used alone or in combination of two or more.

[0080] Commercially available weak solvents (f) 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.).

[0081] Other Solvents The anticorrosion coating composition may further contain other solvents other than the weak solvent (f). The content of the other solvents may be, for example, 30 mass % or less, 10 mass % or less, or 0 mass % of the total mass of the anticorrosion coating composition.

[0082] Examples of other solvents include those commonly used in the art, such as toluene, xylene, isobutyl alcohol, and methyl ethyl ketone. These may be used alone or in combination of two or more.

[0083] Silane Coupling Agent (e) The anticorrosion coating composition may contain a silane coupling agent (e), which improves the adhesion between the anticorrosion coating film and the metal substrate.

[0084] The silane coupling agent (e) may have at least one of a trimethoxysilyl group and a triethoxysilyl group.

[0085] Examples of silane coupling agents having a trimethoxysilyl group include methyltrimethoxysilane, 3-aminopropyltrimethoxysilane, (3-glycidyloxypropyl)trimethoxysilane, n-propyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane, phenyltrimethoxysilane, trifluoropropyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, and 3-chloropropyltrimethoxysilane. These may be used alone or in combination of two or more.

[0086] Examples of silane coupling agents having a triethoxysilyl group include methyltriethoxysilane, 3-aminopropyltriethoxysilane, (3-glycidyloxypropyl)triethoxysilane, n-propyltriethoxysilane, butyltriethoxysilane, isobutyltriethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltriethoxysilane, octadecyltriethoxysilane, phenyltriethoxysilane, tridecafluorooctyltriethoxysilane, and 3-chloropropyltriethoxysilane. These may be used alone or in combination of two or more.

[0087] The content of the silane coupling agent (e) is, for example, 0.5% by mass or more and 5% by mass or less, based on the solid content of the anticorrosion coating composition. The content of the silane coupling agent (e) may be 1.0% by mass or more, or 2.0% by mass or more. The content of the silane coupling agent (e) may be 4.0% by mass or less, or 3.0% by mass or less.

[0088] Others The anticorrosion coating composition may contain other components, such as various additives.

[0089] Examples of additives include anti-sagging agents, anti-settling agents, color-shifting inhibitors, anti-foaming agents, anti-popping agents, leveling agents, and matting agents. These may be used alone or in combination of two or more.

[0090] Preparation Method The anticorrosion coating composition is prepared by mixing the base agent, the curing agent, and, if necessary, diluents and the like, by a method known to those skilled in the art. A commonly used mixing device, such as a paint shaker or a mixer, is used for mixing. 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). Examples of diluents include the same solvents as those listed as being capable of being contained in the base agent.

[0091] The base agent is prepared by mixing the above components in the same manner as above. The curing agent is also prepared in the same manner.

[0092] [Coated Article] A coated article according to the present disclosure comprises a metal substrate and a primer coating film formed on the substrate from the above-described anticorrosion coating composition.

[0093] - Application Method The anticorrosion coating composition is applied by a common method such as with a brush, roller or spray.

[0094] Substrate: The substrate to be coated with the anticorrosive coating composition is not particularly limited as long as corrosion resistance is required. The substrate is typically a metal. Examples of metals include iron, copper, aluminum, tin, zinc, and alloys thereof.

[0095] Specific examples of substrates include cold-rolled steel sheets, hot-rolled steel sheets, stainless steel, 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. More specific examples of substrates include ships, vehicles (e.g., railway cars and large vehicles), aircraft, bridges, offshore structures, plants, tanks (e.g., oil tanks), pipes, steel pipes, cast iron pipes, and other steel structures and buildings.

[0096] The substrate may be one that has been subjected to blasting, anti-rust coating, shop primer coating, or organic or inorganic zinc-rich primer coating. The substrate may also have a previous coating film (a coating film other than the primer coating that was formed before the primer coating film was formed).

[0097] Primer Coating Film The anticorrosive coating composition forms a primer coating film with excellent anticorrosion properties. The thickness of the primer 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 primer coating film is, for example, 10 μm or more and 300 μm or less. The anticorrosive coating composition may be applied multiple times to form a primer coating film with a laminated structure.

[0098] The resistance value of a 60 μm thick primer coating film after immersion in ion-exchanged water at 35° C. for 24 hours (hereinafter referred to as the wet coating resistance value) was 1.0×10 ９ Ω cm ２ It can be 1.0 x 10 or more. ９ Ω cm ２ A coating film having a wet coating resistance value of 5.0×10 or more has very high corrosion resistance. ９ Ω cm ２ It can be 1.0×10 or more. １０ Ω cm ２ It can be 1.0×10 or more. １１ Ω cm ２ It could be more than that.

[0099] The resistance value (hereinafter referred to as volume resistance value) of the primer coating film after immersion in ion-exchanged water at 35°C for 24 hours was 1.7 x 10 ８ Ω cm or more. ８ A coating film having a volume resistivity of Ω cm or more has very high corrosion resistance. ９ Ω cm or more, and may be 1.7×10 １０ It can be Ω·cm or more.

[0100] The wet coating resistance and volume resistivity are calculated as follows: An anticorrosion coating composition is applied to an SS400 grid-blasted steel plate so that the dry coating thickness is 60 μm, and the plate is dried at 23° C. for one week to prepare a coated plate. The coated plate is then immersed in ion-exchanged water for 24 hours in a thermostatic chamber at 35° C.

[0101] Thereafter, the platinum electrode 3 and the coated plate 4 are immersed in ion-exchanged water 2 in a thermostatic chamber 1 at 35°C in the resistance value measuring device 10 shown in Figure 1 to form a circuit with the platinum electrode 3 and the coated plate 4 as electrodes. A high resistance measuring device 5 (for example, a high resistance measuring device B2985A manufactured by Keysight) is used to measure the resistance. The evaluation area of ​​the coated plate 4 is the area of ​​a circle with a diameter of 1 cm. The temperature of the thermostatic chamber 1 is measured by a temperature sensor 6 and a thermometer 7.

[0102] A voltage of ±0.5 (V) is applied between the electrodes with a 60-second interval between voltage changes (see Figure 2), and the current value is recorded every 60 seconds. The absolute values ​​of the differences in the current values ​​after 60 seconds and 120 seconds, after 120 seconds and 180 seconds, after 180 seconds and 240 seconds, after 240 seconds and 300 seconds, and after 300 seconds and 360 seconds are averaged, and the resistance value is calculated according to Ohm's law V = IR. In this formula, V is 1 (V), which is the differential voltage. The obtained resistance value is multiplied by the evaluation area to obtain the wet coating resistance value (Ω cm ２ The volume resistivity (Ω·cm) is obtained by dividing the wet coating resistance value obtained by the coating thickness of the test piece.

[0103] Other coating films may be formed adjacent to the primer coating film. That is, the coated article may comprise a substrate, a primer coating film formed on the substrate, and another coating film formed adjacent to the primer coating film. Specific examples of other coating films include an intermediate coating film, a top coating film, and a dual-purpose intermediate and top coating film.

[0104] The other coating film may be formed from a coating composition containing at least one selected from the group consisting of polyisocyanates, epoxy resins, and polyamines. Polyisocyanates, epoxy resins, and polyamines readily react with or interact with the functional groups of the modified epoxy resin (a-1) that forms the primer coating film. This further improves interval adhesion.

[0105] The thickness of the other 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 other coating film is, for example, 20 μm or more and 80 μm or less. The coating composition may be applied multiple times to form the other coating film with a laminate structure.

[0106] Third Coating A third coating may be formed on another coating. The third coating is provided adjacent to the other coating. The third coating is formed, for example, by a topcoat paint and / or a functional paint.

[0107] Examples of topcoat paints 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.

[0108] 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.

[0109] [Production Example A-1] Production of Novolac Epoxy Resin (a-12-1) 250 g of p-tert-butylphenol novolac resin (trade name: Hitanol #1133, manufactured by Hitachi Chemical Co., Ltd.), 250 g of octylphenol novolac resin (trade name: Hitanol #1501, manufactured by Hitachi Chemical Co., Ltd.), and 1,440 g of epichlorohydrin were charged into a 2-L reactor equipped with a thermometer, a stirrer, and a condenser, and stirred to form a homogeneous solution. Next, 268 g of 48% by mass sodium hydroxide was added dropwise at 60 to 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 completion of the dropwise addition, the mixture was aged at 100 to 120°C for 2 hours, and the reaction was terminated when the theoretical amount of water had flowed out.

[0110] To the resulting epichlorohydrin solution of the epoxy compound, 150 g of xylene was added, and the mixture was washed with a large amount of water. After removing the produced sodium chloride and excess sodium hydroxide, the mixture was neutralized with a 3% by mass aqueous phosphoric acid solution. Next, the epichlorohydrin and xylene were distilled off under reduced pressure, and 460 g of a high-boiling paraffin solvent (product name: Swazol 310, manufactured by Cosmo Oil) was added to obtain a liquid novolac epoxy resin (a-12-1).

[0111] The novolac epoxy resin (a-12-1) had a weight average molecular weight of 8,500, an epoxy equivalent of 1010 g / eq, and a solid content of 60% by mass.

[0112] [Production Example A-2] Production of Novolac Epoxy Resin (a-12-2) Novolac epoxy resin (a-12-2) was obtained in the same manner as in Production Example 1, except that the amount of epichlorohydrin was changed to 2040 g. The weight-average molecular weight of the novolac epoxy resin (a-12-2) was 6,500, the epoxy equivalent was 1000 g / eq, and the solids content was 60 mass%.

[0113] [Production Example A-3] Production of Novolac Epoxy Resin (a-12-3) Novolac epoxy resin (a-12-3) was obtained in the same manner as in Production Example 1, except that the amount of epichlorohydrin was changed to 1,040 g. The weight-average molecular weight of the novolac epoxy resin (a-12-3) was 9,500, the epoxy equivalent was 1,020 g / eq, and the solids content was 60 mass%.

[0114] [Production Example A-4] Production of other epoxy resin (a-2-1) Other novolac-type epoxy resin (a-2-1) was obtained in the same manner as in Production Example 1, except that the amount of epichlorohydrin was changed to 2,320 g. The weight-average molecular weight of the other novolac-type epoxy resin (a-2-1) was 5,700, the epoxy equivalent was 995 g / eq, and the solids content was 60 mass%.

[0115] [Production Example D-1] Production of Antifoaming Agent (d-1) 100 parts of xylene were charged into a 1000 ml reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen gas inlet. The reaction vessel was heated to 90°C while introducing nitrogen gas, and the following solution was added dropwise at a constant rate over 90 minutes using the dropping funnel. One hour after the completion of the dropwise addition, 1.5 parts of a polymerization initiator (t-butylperoxy-2-ethylhexanoate) was added, and the reaction was continued for another 3 hours while maintaining the temperature at 90°C. After the reaction was completed, the solids content was adjusted to 30% with xylene, yielding a defoaming agent having structural units derived from alkyl(meth)acrylate. The number average molecular weight of the resulting defoaming agent was 125,000.

[0116] Solution Octadecyl methacrylate 300 parts Xylene 100 parts t-butylperoxy-2-ethylhexanoate 4.5 parts

[0117] [Production Example D-2] Production of defoaming agent (d-2) A defoaming agent (d-2) having a number average molecular weight of 62,000 was obtained in the same manner as in Production Example D-1, except that the amount of t-butylperoxy-2-ethylhexanoate contained in the dropping solution was changed to 9 parts.

[0118] [Production Example D-3] Production of defoaming agent (d-3) A defoaming agent (d-3) having a number average molecular weight of 30,000 was obtained in the same manner as in Production Example D-1, except that the amount of t-butylperoxy-2-ethylhexanoate contained in the dropping solution was changed to 18 parts.

[0119] [Production Example D-4] Production of defoaming agent (d-4) A defoaming agent (d-4) having a number average molecular weight of 27,500 was obtained in the same manner as in Production Example D-1, except that the amount of t-butylperoxy-2-ethylhexanoate contained in the dropping solution was changed to 20 parts.

[0120] [Production Example D-5] Production of Defoaming Agent (d-5) 200 parts of xylene were charged into a 1000 ml reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen gas inlet. The reaction vessel was heated to 90°C while introducing nitrogen gas, and the following solution was added dropwise at a constant rate over 90 minutes using the dropping funnel. One hour after the completion of the dropwise addition, 1.5 parts of a polymerization initiator (t-butylperoxy-2-ethylhexanoate) was added, and the reaction was continued for another 3 hours while maintaining the temperature at 90°C. After the reaction was completed, the solids content was adjusted to 30% with xylene, yielding a defoaming agent (d-5) having structural units derived from alkyl (meth)acrylate. The number-average molecular weight of the resulting defoaming agent was 750,000.

[0121] Solution Octadecyl methacrylate 300 parts Xylene 400 parts t-butylperoxy-2-ethylhexanoate 4.5 parts Ethylene glycol dimethacrylate 0.6 parts

[0122] [Production Example D-6] Production of defoaming agent (d-6) A defoaming agent (d-6) having a number average molecular weight of 1,250,000 was obtained in the same manner as in Production Example D-5, except that the amount of ethylene glycol dimethacrylate contained in the dropping solution was changed to 0.9 parts.

[0123] [Production Example D-7] Production of defoaming agent (d-7) A defoaming agent (d-7) having a number average molecular weight of 2,600,000 was obtained in the same manner as in Production Example D-5, except that the amount of ethylene glycol dimethacrylate contained in the dropping solution was changed to 1.2 parts.

[0124] [Production Example D-8] Production of defoaming agent (d-8) A defoaming agent (d-8) having structural units derived from alkyl vinyl ether was obtained in the same manner as in Production Example D-1, except that the solution to be dropped was changed as follows. The number average molecular weight of the defoaming agent (d-8) was 85,000.

[0125] Solution Hexadecyl methacrylate 190 parts Lauryl vinyl ether 110 parts t-butylperoxy-2-ethylhexanoate 3.0 parts

[0126] [Production Example D-9] Production of Antifoaming Agent (d-9) 20 parts of polybutadiene and 185 parts of xylene were charged into a 1000 ml reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen gas inlet. The reaction vessel was heated to 100°C while introducing nitrogen gas, and then the following solution was added dropwise at a constant rate over 4 hours using the dropping funnel. One hour after the completion of the dropwise addition, 2.0 parts of a polymerization initiator (t-butylperoxy-2-ethylhexanoate) was added, and the reaction was continued for another 2 hours while maintaining the temperature at 100°C. After the reaction was completed, the solids content was adjusted to 30% with xylene, yielding an antifoaming agent (d-9) having structural units derived from alkyl (meth)acrylate. The number average molecular weight of the resulting antifoaming agent was 56,000.

[0127] Solution: Methacrylic acid lauryl ester 180 parts, xylene 180 parts, t-butylperoxy-2-ethylhexanoate 0.8 parts

[0128] [Other defoaming agents] Silicone-based defoaming agent (d-10) Product name: KF-96A-500CS, dimethyl silicone oil, molecular weight: 50,000 (kinematic viscosity at 25°C: 500 mm ２ The number average molecular weight of the silicone oil can be calculated by measuring the kinematic viscosity using an Ubbelohde viscometer according to ASTM D445-46T and then using the Warrik formula or the like.

[0129] Details of each component shown in Tables 1 to 6 are as follows: Epoxy resins (a) Bisphenol A type epoxy resin (a-11-1): trade name "jER1007", manufactured by Mitsubishi Chemical Corporation, weight average molecular weight 10,000, epoxy equivalent 1975 g / eq, solid content 100 mass% Bisphenol A type epoxy resin (a-11-2): trade name "jER1009", manufactured by Mitsubishi Chemical Corporation, weight average molecular weight 20,000, epoxy equivalent 2850 g / eq, solid content 100 mass% Other epoxy resins (a-2-2): non-novolac type and non-bisphenol A type, trade name "Epolite 100MF", manufactured by Kyoeisha Chemical Co., Ltd., weight average molecular weight 420, epoxy equivalent 145 g / eq, solid content 100 mass%

[0130] Polyamines (b) Alicyclic polyamine (b-1): 1,3-bis(aminomethyl)cyclohexane, manufactured by Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent: 35.5 g / eq Non-alicyclic polyamine (b-2-1): m-xylylenediamine, aromatic polyamine, manufactured by Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent: 34.1 g / eq Non-alicyclic polyamine (b-2-2): diethylenetriamine, aliphatic polyamine, manufactured by Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent: 20.7 g / eq

[0131] Silane coupling agent (e) Silane coupling agent (e-1): Trade name KBM-403, containing a trimethoxysilyl group, manufactured by Shin-Etsu Chemical Co., Ltd. Silane coupling agent (e-2): Trade name KBE-403, containing a triethoxysilyl group, manufactured by Shin-Etsu Chemical Co., Ltd.

[0132] Anti-rust pigment: CLF-102, aluminum tripolyphosphate, manufactured by Guangxi Academy of Chemical Technology. Weak solvent: Solvesso 100, manufactured by Esso Oil.

[0133] [Examples 1 to 35, Comparative Examples 1 to 16] A base agent and a curing agent were each prepared according to the formulations shown in Tables 1 to 6. Anticorrosion coating compositions were prepared by mixing the base agent and the curing agent. The blending amounts in Tables 1 to 6 are mass ratios relative to 100 parts by mass of the solid content of the anticorrosion coating composition.

[0134] (Measurement of Resistance Value) Each anticorrosive coating composition was spray-coated onto an SS400 grid-blasted steel plate and dried for one week at 23° C. to prepare a coated plate having a primer coating film with a thickness of 60 μm. The resulting coated plate was immersed in ion-exchanged water in a thermostatic chamber at 35° C. for 24 hours.

[0135] Thereafter, the coated plate 4 was assembled in the same manner as above using the resistance value measuring device 10 shown in FIG. 1. Subsequently, a voltage of ±0.5 (V) was applied between the electrodes as shown in FIG. 2, and the resistance value was calculated in the same manner as above. The obtained resistance value was multiplied by the evaluation area to obtain the coating resistance value (Ω cm ２ The obtained wet coating resistance value was divided by the coating thickness of the test piece to obtain a volume resistivity value (Ω·cm).

[0136] [Evaluation] The anticorrosion coating compositions were evaluated by the following methods. The evaluation results are shown in Tables 1 to 6.

[0137] (1) Barrier Property The above wet resistance value was evaluated according to the following criteria: A rating of A indicates excellent barrier property.

[0138] (Evaluation criteria) A: 1.0 x 10 ９ Ω cm ２ or more B: 1.0×10 ９ Ω cm ２ less than

[0139] (2) Appearance The anticorrosive coating composition was spray-coated onto an SS400 grit-blasted steel plate in a low-temperature environment (0°C) where it is difficult to obtain an antifoaming effect. The coating was then dried at 0°C for one week to produce a coated plate having a primer coating film with a thickness of 60 μm. The appearance of the resulting primer coating film was evaluated according to the following criteria. A rating of A indicates excellent appearance.

[0140] (Evaluation criteria) A: No abnormalities B1: Bubble marks observed B2: Cracks observed

[0141] (3) Low-Temperature Curing Property The anticorrosion coating composition was applied to a degreased polished steel plate (150 x 70 x 0.8 mm) using an air spray to a dry film thickness of approximately 60 μm, and then dried at 0°C for 16 hours to obtain a test coating film. The test coating film was touched with a finger and evaluated for curability according to the following criteria. Japanese Patent No. 3652864 can be referred to as a method for evaluating low-temperature curing property. A rating of 3 or 4 can be evaluated as excellent low-temperature curing property.

[0142] (Evaluation criteria) 4: The coating film does not shift even when pressed firmly with a finger. 3: The coating film shifts when pressed firmly with a finger, but does not leave a mark when rubbed lightly. 2: A mark is left when rubbed lightly with a finger, but no paint is left when touched lightly. 1: Paint is left when touched lightly with a finger.

[0143] (4) Corrosion Resistance The anticorrosion coating composition immediately after preparation was applied to grid-blasted steel plates (7 cm × 15 cm × 3.2 mm) using an air spray to a dry film thickness of approximately 60 μm, and then cured for 7 days at 23°C and 50% RH to produce three coated plates with primer coatings. Two cuts, 80 mm long and 0.1 mm wide and deep enough to reach the substrate, were made in the primer coating using a cutter, intersecting at 60° in the center of the coating.

[0144] Next, the coated plates were subjected to a combined cyclic corrosion test (CCT test) in accordance with JIS K 5600-7-9 Cyclic Corrosion Test (Annex 1 Cycle D). Specifically, a 120-cycle accelerated corrosion test was performed using a combined cyclic corrosion tester (manufactured by Suga Test Instruments Co., Ltd., Model CCT-1) in Mode D.

[0145] In the CCT test, one cycle consisted of three steps: (1) spraying a 50±10 g / L aqueous sodium chloride solution in an environment of 30±2°C for 30 minutes, (2) wetting in a humid environment of a temperature of 30±2°C and a humidity of 95±3% RH for 1.5 hours, and (3) drying at temperatures of 50±2°C and 30±2°C for 2 hours each.

[0146] After the CCT test, the maximum blister width (mm) on the cut side of each of the three coated panels was measured and averaged. The average maximum blister width was evaluated according to the following criteria. A rating of 3 or 4 indicates excellent corrosion resistance.

[0147] (Evaluation Criteria) 4: Average maximum bulge width is 0 mm or more and less than 1.0 mm 3: Average maximum bulge width is 1.0 mm or more and less than 4.0 mm 2: Average maximum bulge width is 4.0 mm or more and less than 6.0 mm 1: Average maximum bulge width is 6.0 mm or more

[0148] (5) Adhesion The coating films obtained with the anticorrosion coating compositions were evaluated in accordance with JIS K5600-5-6. Specifically, the anticorrosion coating compositions were applied to zinc-plated steel sheets (150 × 70 × 3.2 mm) that had been exposed outdoors for six months using an air spray to a dry film thickness of approximately 60 μm, and the sheets were then aged for seven days at 23°C and 50% RH. The sheets were then left to stand for seven days at 50°C and 95% RH to obtain test coating films. Referring to "7. Procedure" in JIS K5600-5-6, six incisions were made in each direction of the test coating film at 2 mm intervals. Pressure-sensitive adhesive tape was applied to the incised surface and then peeled off. The resulting coating surfaces were visually observed and classified in accordance with Table 1 of Section 8.3 of JIS K5600-5-6. The classification was evaluated according to the following criteria. A rating of 3 or 4 indicates excellent adhesion.

[0149] (Evaluation criteria) 4: Class 0 or Class 1 3: Class 2 2: Class 3 1: Class 4 or Class 5

[0150] (6) Recoatability The coating film obtained with the anticorrosion coating composition was evaluated with reference to JIS K 5551:2018 7.11 Topcoat Compatibility. Specifically, the anticorrosion coating composition was applied to a bonded steel plate (150 mm x 70 mm x 0.8 mm) using a brush to a dry film thickness of approximately 60 μm, and then dried at 5°C for 24 hours to obtain a test coating film. A topcoat paint (product name: Hi-Pon 30 Fine Intermediate Coat, manufactured by Nippon Paint Co., Ltd.) was applied to the test coating film using a brush. Evaluation items were set from the perspective of workability when applying the topcoat paint and the resolubility of the test coating film, and the recoatability was evaluated according to the following criteria. A rating of 3 or 4 can be evaluated as having excellent recoatability.

[0151] (Evaluation items) i: Painting workability: whether the brush feels heavy ii: Re-dissolving: whether the test coating film has dissolved iii: Re-dissolving: whether lifting has occurred

[0152] (Evaluation criteria) 4: No problem in any of the above items. 3: There is a problem in one of the above items. 2: There is a problem in two of the above items. 1: There is a problem in all of the above items.

[0153] (7) Treadability The anticorrosive coating composition was applied to a bonded steel plate (900 x 225 x 0.8 mm) using an air spray to a dry film thickness of approximately 60 μm, and then cured at 0°C for 16 hours to obtain a test coating. The test coating surface was stepped on with a shoe, and the entire body weight was applied for 3 seconds, after which the treadability was evaluated according to the following criteria. A rating of 3 or 4 can be evaluated as excellent treadability. JP 2010-24408 A can be referenced for a method of evaluating treadability.

[0154] (Evaluation criteria) 4: No shoe marks left on the coating film. 3: No shoe marks left on the coating film, but it was sticky. 2: Sticky and shoe marks left on the coating film. 1: Paint adhered to the soles of shoes.

[0155] (8) Shrinkage Resistance An alkyd resin paint (trade name: Quick Dry PZ Helgon Eco, manufactured by Nippon Paint Co., Ltd.) was applied to a hot-dip galvanized steel sheet (150 x 70 x 3.2 mm) using a brush to a dry film thickness of about 60 μm, and dried for one day under conditions of 23°C and 50% RH. Next, an anticorrosion coating composition was applied using a brush to a dry film thickness of about 50 μm, and dried for one day under conditions of 23°C and 50% RH. The shrinkage resistance of the obtained test coating film was evaluated according to the following criteria. A rating of 3 or 4 can be evaluated as excellent shrinkage resistance.

[0156] (Evaluation criteria) 4: No shrinkage occurred 3: Shrinkage occurred in 10% or less of the coating area 2: Shrinkage occurred in 50% or less of the coating area 1: Shrinkage occurred over the entire coating area

[0157] (9) Thermal Cycling Resistance The thermal cycling resistance of coating films obtained with the anticorrosive coating composition was evaluated with reference to JIS-K-5600-7-4. Specifically, the anticorrosive coating composition was applied to a bonded steel plate (150 mm x 70 mm x 0.8 mm) using a brush to a dry film thickness of approximately 60 μm, and then aged for 16 hours at 23°C and 50% RH to obtain a test coating film. A topcoat (product name: Hi-Pon 30 Fine Intermediate Coat, manufactured by Nippon Paint Co., Ltd.) was applied to the test coating film using a brush, and the test coating film was aged for 7 days at 23°C and 50% RH. The resulting laminated coating film was subjected to a thermal cycling test for 50 cycles, consisting of 18 hours at 23±2°C, 3 hours at -20°C, and 3 hours at 50±3°C. After 50 cycles, the thermal cycling resistance was evaluated according to the following evaluation criteria. A rating of 3 or 4 indicates excellent thermal cycling resistance.

[0158] (Evaluation criteria) 4: No abnormalities in appearance 3: Cracks occurred in 10% or less of the surface area 2: Cracks occurred in 50% or less of the surface area 1: Cracks occurred over the entire surface

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[0165] The present invention provides an anticorrosion coating composition having excellent corrosion prevention properties, which is particularly suitable as an undercoat for steel materials used in large structures such as plants, bridges, steel towers, and buildings.

[0166] 10 Resistance value measuring device 1 Thermostatic bath 2 Ion-exchanged water 3 Platinum electrode 4 Coated plate 5 High resistance measuring device 6 Temperature sensor 7 Thermometer

Claims

1. An anticorrosion coating composition comprising a base agent (I) and a curing agent (II), wherein the base agent (I) comprises an epoxy resin (a), the epoxy resin (a) comprises at least one of a bisphenol A type epoxy resin (a-11) and a novolac type epoxy resin (a-12), each having a weight average molecular weight of 6,000 or more and 12,000 or less, the curing agent (II) comprises a polyamine (b) and an alkylphenol (c), the polyamine (b) comprises an alicyclic polyamine (b-1) having a cyclic aliphatic hydrocarbon group to which an amino group is bonded and a non-alicyclic polyamine (b-2) not having a cyclic aliphatic hydrocarbon group to which an amino group is bonded, an alkylphenol (c) content of the curing agent (II) containing a vinyl antifoaming agent (d) having a number average molecular weight of 30,000 to 100,000, or 300,000 to 2,000,000; and an alkylphenol (c) content of the curing agent (II) containing a vinyl antifoaming agent (d) having a number average molecular weight of 30,000 to 100,000, or 300,000 to 2,000,000. The anticorrosion coating composition includes: at least one of the main agent (I) and the curing agent (II) containing a structural unit derived from at least one monomer selected from the group consisting of alkyl(meth)acrylate, alkyl vinyl ether, and olefin; the vinyl antifoaming agent (d) having a number average molecular weight of 30,000 to 100,000, or 300,000 to 2,000,000; the alicyclic polyamine (b-1) is present in an amount of 30 to 80% by mass of the solid content of the curing agent (II); the non-alicyclic polyamine (b-2) is present in an amount of 2 to 45% by mass of the solid content of the curing agent (II); the alkylphenol (c) is present in an amount of 5 to 60% by mass of the solid content of the curing agent (II); and the vinyl antifoaming agent (d) is present in an amount of 0.005 to 3 parts by mass, relative to 100 parts by mass of the anticorrosion coating composition.

2. The resistance of a 60 μm thick coating film formed from the anticorrosion coating composition after immersion in ion-exchanged water at 35° C. for 24 hours is 1.0×10 ９ Ω cm ２ The anticorrosion coating composition according to claim 1, wherein 3. The volume resistivity of the coating film formed from the anticorrosion coating composition after immersion in ion-exchanged water at 35°C for 24 hours is 1.7 x 10 ８ 3. The anticorrosion coating composition according to claim 1, wherein the anticorrosion coefficient is Ω·cm or more.

4. The corrosion-protective coating composition according to any one of claims 1 to 3, wherein the non-alicyclic polyamine (b-2) comprises at least one member selected from the group consisting of an aliphatic polyamine, a polyamine having an aromatic hydrocarbon group, and a polyamine having a heterocycle.

5. The anticorrosion coating composition according to any one of claims 1 to 4, wherein the main component (I) further contains a silane coupling agent (e) having at least one of a trimethoxysilyl group and a triethoxysilyl group.

6. The anticorrosion coating composition according to any one of claims 1 to 5, further comprising a weak solvent (f).

7. The anticorrosion coating composition according to any one of claims 1 to 6, wherein the main agent (I) further contains a pigment (g), and the volume concentration of the pigment in the main agent (I) is 25% by volume or more and 55% by volume or less.

8. A coated article comprising: a metal substrate; and a primer coating film formed on the substrate from the anticorrosion coating composition according to any one of claims 1 to 7.

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