Anticorrosive coating composition

Abstract

The anticorrosive coating composition comprises 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) having a weight average molecular weight of 6000 or more and 12000 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) having no cyclic aliphatic hydrocarbon group to which an amino group is bonded, and at least one of the base agent (I) and the curing agent (II) comprises an alkyl (meth)acrylate, an alkyl biphenyl, an alkyl acrylate, an alkyl tertiary amine ... an alkylphenol (c) having a structural unit derived from at least one monomer selected from the group consisting of diphenyl ether and olefin, and a vinyl-based defoaming agent (d) having a number average molecular weight of 30,000 to 100,000, or 300,000 to 2,000,000, wherein the content of the alicyclic polyamine (b-1) is 30% by mass to 80% by mass of the solid content of the curing agent (II), the content of the non-alicyclic polyamine (b-2) is 2% by mass to 45% by mass of the solid content of the curing agent (II), the content of the alkylphenol (c) is 5% by mass to 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 parts by mass to 3 parts by mass relative to 100 parts by mass of the anticorrosive coating composition.

Description

[Technical field]

[0001] The present invention relates to an anticorrosive coating composition. [Background technology]

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

[0003] [Patent Document 1] Patent No. 6832122 Summary of the Invention [Problem to be solved by the invention]

[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 anticorrosive coating composition having excellent anticorrosive properties. [Means for solving the problem]

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

[0007] According to the present invention, there is provided an anticorrosive coating composition having excellent anticorrosive properties. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram showing an overview of an apparatus for measuring a resistance value. [Diagram 2] 1 is a graph showing a change in applied voltage when measuring a resistance value. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0010] One of the reasons for the decrease 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) improves, the corrosion resistance increases and the electrical resistance of the coating film also increases.

[0011] In the curing system of epoxy resin and polyamine, the viscosity is likely to increase as the curing reaction proceeds, and molecular motion within the coating film is restricted. Therefore, the curing reaction does not proceed beyond a certain level, and unreacted amino groups and low molecular weight components tend to remain. These components reduce the barrier properties and the corrosion resistance.

[0012] In the present disclosure, an epoxy resin (a) that has a relatively high molecular weight and easily forms a planar structure is used. In addition, an alicyclic polyamine (b-1) that easily forms a planar structure is used as a curing agent. This makes the coating film denser and improves the barrier function.

[0013] Furthermore, a specific vinyl-based defoaming agent (d) is used. By using the specific vinyl-based defoaming agent (d) in the system containing the above specific epoxy resin (a), the 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 is adsorbed to the generated foam, and the defoaming agent aggregates with itself, causing the foam to aggregate. The aggregated foam rises to the surface of the coating film due to buoyancy. When the foam rises 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 it, causing it to stretch and eventually break.

[0015] The vinyl-based defoaming agent (d) has a number-average molecular weight of 30,000 to 100,000 or 300,000 to 2,000,000. Therefore, the vinyl-based defoaming agent (d) is difficult to dissolve in the epoxy resin (a) having a weight-average molecular weight of 6,000 to 12,000. As a result, the vinyl-based defoaming agent (d) can easily adsorb to the generated bubbles and fully exert its effect. In addition, it is known that the vinyl-based defoaming agent has a high surface tension and is excellent in foam breaking effect. As a result, the coating film obtained by the anticorrosive coating composition of the present disclosure is dense and has a high barrier function.

[0016] Hereinafter, the epoxy equivalent is determined based on the solid content mass and is determined 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 anticorrosive coating composition is the total content of the anticorrosive coating composition excluding volatile components (typically, solvents). The solid content concentration of the anticorrosive coating composition can be calculated from the residue when the anticorrosive coating composition is heated at 140°C according to JIS K 5601-1-2 Heating Residue Measurement Method.

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

[0021] Main component (I) The base resin (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 type epoxy resin (a-11) and a novolac type epoxy resin (a-12) having a weight average molecular weight of 6000 or more and 12000 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 the metal substrate. From the viewpoints of moisture resistance and toughness, the specific epoxy resin (a-1) may be a novolac type epoxy resin (a-12).

[0024] The weight average molecular weight of the specific epoxy resin (a-1) may be 6500 or more, or may be 8500 or more. The weight average molecular weight of the specific epoxy resin (a-1) may be 11000 or less, or may be 10000 or less.

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

[0026] Examples of the novolac type epoxy resin (a-12) include phenol novolac type, cresol novolac type, and novolac type of bisphenol A. The novolac type 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 anticorrosive coating composition. When the content of the specific epoxy resin (a-1) is 15% by mass or more, the curability can be improved. When the content of the specific epoxy resin (a-1) is 60% by mass or less, the relative proportion of the pigment in the coating film increases, so that the hiding power can be improved. 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 ratio of the specific epoxy resin (a-1) in the entire epoxy resin (a) is, for example, 60 mass% or more and 100 mass% or less. This makes it easier for the specific epoxy resin (a-1) to exert its effect. The above ratio of the specific epoxy resin (a-1) may be 70 mass% or more, or 80 mass% or more. The above ratio of the specific epoxy resin (a-1) may be 100 mass%, 95 mass% or less, or 90 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 terms of increasing the 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 terms of increasing the 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 6000 or more than 12000, a bisphenol A epoxy resin having a weight average molecular weight of less than 6000 or more than 12000, or an epoxy resin other than the novolac epoxy resin and the bisphenol A epoxy resin.

[0032] Examples of epoxy resins other than novolac type epoxy resins and bisphenol A type epoxy resins include bisphenol type epoxy resins other than bisphenol A type, aromatic epoxy resins such as 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.

[0033] Examples of the biphenyl type, naphthalene type and dicyclopentadiene type include resins in which one or more glycidyl ether groups are substituted at any position of biphenyl, naphthalene, and dicyclopentadiene. Examples of bisphenol type epoxy resins other than bisphenol A type include bisphenol F type, bisphenol S type, bisphenol AD ​​type, 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] Hardener (II) The curing agent (II) includes a polyamine (b) and an alkylphenol (c).

[0035] Polyamines (b) The polyamine (b) is a curing component. The polyamine (b) undergoes a crosslinking reaction with the 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 is easily suppressed when another coating film is laminated on the primer coating film formed by the anticorrosive coating composition.

[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, the curing property can be improved, especially at low temperatures. When the active hydrogen equivalent of the alicyclic polyamine (b-1) is 150 g / eq or less, the barrier property 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 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. The alkylene polyamine is, for example, H 2 NR 1 -NH2 (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. ) is represented. 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 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, 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)benzene, bis(aminoalkyl)naphthalene, 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.

[0043] Examples of heterocyclic polyamines include N-methylpiperazine [CH 3 -N(CH 2 CH 2 ) 2 NH], morpholine [HN(CH 2 CH 2 ) 2 O], 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, the 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 step-in property 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] The term "overcoatability" refers to the performance evaluated with reference to JIS K 5551:2018 7.10, and refers to the performance in which, when a topcoat paint is applied over a primer coating film formed using the anticorrosive coating composition according to the present disclosure, the solubility of the primer coating film is low and there is no hindrance to the workability of the topcoat paint. The term "step-inability" refers to the performance in which, when a worker walks on the coating film, shoe marks are unlikely to be formed on the coating film and peeling of the coating film is minimal.

[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 is 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, the curability can be improved. When the ratio (active hydrogen group amount / epoxy group amount) is 1.2 or less, an excessive increase in reaction points is suppressed, so that the impact resistance of the primer coating film can be improved. The ratio (active hydrogen group amount / epoxy group amount) may be 0.85 or more, or 0.90 or more. The ratio (active hydrogen group amount / epoxy group amount) may be 1.15 or less, or 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 the 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 mixed, the mass ratio (%) of each epoxy resin to the total epoxy resin (a) is calculated by multiplying the mass of the solid content (g) of that epoxy resin by the epoxy equivalent (g / eq). The sum of these products is the amount of epoxy groups.

[0051] Alkylphenols (c) The curing agent further includes an alkylphenol (c), which further improves the curability (particularly the 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 defoamers (d) Vinyl-based defoaming agents (d) have a particularly strong defoaming effect in the curing system of a specific epoxy resin (a) and a specific polyamine (b). Vinyl-based defoaming agents (d) form a denser coating film and improve 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)acrylates, alkyl vinyl ethers, and olefins, 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 has the following general formula: CH 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. It is expressed as:

[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] Alkyl vinyl ethers have the following general formula: CH 2 =CH(R 3 )-OR 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. It is expressed as:

[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 ) (In the formula, 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. It is expressed as:

[0063] R is an alkyl group 5 R 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, nonadecen, icosene, henicosene, butadiene, pentadiene, and hexadiene. These may be used alone or in combination of two or more.

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

[0069] The content of the vinyl-based defoaming agent (d) is 0.005 parts by mass or more and 3 parts by mass or less with respect to 100 parts by mass of the anticorrosive coating composition. When the content of the vinyl-based defoaming 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-based defoaming agent (d) is 3 parts by mass or less, the vinyl-based defoaming agent (d) can be compatible with the anticorrosive coating composition to such an extent that cissing does not occur. The content of the vinyl-based defoaming 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-based defoaming agent (d) may be 1.5 parts by mass or less, or may be 0.5 parts by mass or less.

[0070] Pigments The anticorrosive coating composition may contain a pigment. Examples of the pigment include, without limitation, pigments that are usually blended in coating compositions. Examples of the pigment include extender pigments, coloring pigments, and anticorrosive pigments. These may be used alone or in combination of two or more.

[0071] · 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, suzolite mica, and clarite mica. These may be used alone or in combination of two or more. The content of the extender pigment is not particularly limited.

[0072] Color pigments Examples of color 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 color pigment is not particularly limited.

[0073] Anti-rust pigments Examples of the rust-preventive pigment include phosphate compounds (such as aluminum polyphosphate), molybdate compounds (such as calcium molybdate), zinc compounds (such as zinc sulfate), alkaline earth metal 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 rust-preventive pigment is not particularly limited.

[0074] The total content of 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 the decrease in adhesion. PVC is the volume percentage (%) of the total of various pigments in the total volume of the total resin solid content and various pigments in the anticorrosive coating composition. The PVC of the base agent may be 30% by volume or more, or may be 35% by volume or more. The PVC of the base agent may be 50% by volume or less, or may be 45% by volume or less.

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

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

[0077] The shrinkage resistance refers to the ability to suppress 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 anticorrosive 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 solvents 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 anticorrosive 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 anticorrosive coating composition.

[0082] Examples of other solvents include those commonly used in the art. Examples of other solvents include 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 anticorrosive coating composition may contain a silane coupling agent (e), which improves adhesion between the anticorrosive 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 anticorrosive 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 anticorrosive coating composition may contain other components, such as various additives.

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

[0090] ·Preparation method The anticorrosive coating composition is prepared by mixing the base agent, the curing agent, and, if necessary, the diluting component, etc., by a method known to those skilled in the art. For mixing, a commonly used mixing device such as a paint shaker or a mixer is used. The base agent and the curing agent are usually mixed immediately before use (for example, the agent is mixed and used within 60 minutes). The diluting component can be exemplified by the same solvents as those that can be contained in the base agent.

[0091] The base agent is prepared by mixing the above-mentioned components in the above-mentioned manner. The curing agent can be prepared in the same manner.

[0092] [Painted items] A coated article according to the present disclosure comprises a metal substrate and a primer coating formed on the substrate from the above-mentioned anticorrosive coating composition.

[0093] Painting method The anticorrosive coating composition is applied by a common method such as by brush, roller or spray.

[0094] ·Object to be coated The object (substrate) to be coated with the anticorrosive coating composition is not particularly limited as long as anticorrosive properties are required. The substrate is typically a metal. Examples of metals include iron, copper, aluminum, tin, zinc, and alloys thereof.

[0095] Specific examples of the substrate include cold-rolled steel sheets, hot-rolled steel sheets, stainless steel, electrolytic galvanized 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 the substrate include ships, vehicles (e.g., railway cars, 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, organic or inorganic zinc-rich primer coating, etc. The substrate may have a previous coating film (a coating film other than the primer coating film that was formed before the above primer coating film was formed).

[0097] Primer coating The anticorrosive coating composition forms a primer coating film having excellent anticorrosive 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 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 having a laminated structure.

[0098] The resistance value of a 60 μm thick primer coating after immersion in 35° C. ion-exchanged water for 24 hours (hereinafter referred to as the wet coating resistance value) is 1.0×10 9 Ω cm 2 It can be more than 1.0×10 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 greater than or equal to 1.0×10 10 Ω cm 2 It can be greater than or equal to 1.0×10 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 after immersion in 35°C ion-exchanged water for 24 hours is 1.7 x 10 8 It can be more than 1.7×10 Ω·cm. 8 A coating film with a volume resistivity of Ω·cm or more has very high corrosion resistance. The above volume resistivity is 1.7×10 9 Ω cm or more, 1.7×10 10 It can be more than Ω·cm.

[0100] The wet coating resistance and volume resistivity are calculated as follows: The anticorrosive 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 the ion-exchanged water 2 in the thermostatic chamber 1 at 35° C. of the resistance value measuring device 10 in FIG. 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 Corporation) is used to measure the resistance value. 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, 120 seconds and 180 seconds, 180 seconds and 240 seconds, 240 seconds and 300 seconds, and 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 the differential voltage, or 1 (V). 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 coatings Another coating film may be provided adjacent to the primer coating film. That is, the coated article may include a substrate, a primer coating film formed on the substrate, and another coating film formed adjacent to the primer coating film. Specific examples of the other coating film include an intermediate coating film, a top coating film, and a coating film that can be used both as an intermediate and a top coating film.

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

[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 having a laminated structure.

[0106] Third Coat A third coating film may be formed on the other coating films. The third coating film is provided adjacent to the other coating films. The third coating film 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, silicon 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 silicon modified resin paints. Examples of functional paints include photocatalyst paints that exhibit a self-cleaning function against pollutants, and antifouling paints that prevent the attachment of marine organisms, etc. EXAMPLES

[0108] Hereinafter, the present embodiment will be described in more detail using examples, but the present embodiment is not limited by the examples. In the examples, "parts" and "%" are based on mass unless otherwise specified.

[0109] [Production Example A-1] Production of novolac-type epoxy resin (a-12-1) In a 2L reactor equipped with a water separator equipped with a thermometer, a stirrer, and a cooling tube, 250g of p-tert-butylphenol novolac resin (trade name: Hitanol #1133, Hitachi Chemical Co., Ltd.), 250g of octylphenol novolac resin (trade name: Hitanol #1501, Hitachi Chemical Co., Ltd.), and 1440g of epichlorohydrin were charged and stirred to form a homogeneous solution. Then, 268g 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 azeotroped with epichlorohydrin and removed outside the system using a water separator, while the epichlorohydrin was refluxed in the system. After the dropwise addition was completed, the mixture was aged at 100 to 120°C for 2 hours, and the reaction was terminated when the theoretical amount of water flowed out.

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

[0112] [Production Example A-2] Production of novolac-type epoxy resin (a-12-2) A novolac-type 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 novolac epoxy resin (a-12-2) had a weight average molecular weight of 6,500, an epoxy equivalent of 1000 g / eq, and a solid content of 60 mass%.

[0113] [Production Example A-3] Production of novolac-type epoxy resin (a-12-3) A novolac-type 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 novolac epoxy resin (a-12-3) had a weight average molecular weight of 9,500, an epoxy equivalent of 1020 g / eq, and a solid content of 60 mass%.

[0114] [Production Example A-4] Production of other epoxy resins (a-2-1) Another novolak-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 other novolac type epoxy resin (a-2-1) had a weight average molecular weight of 5,700, an epoxy equivalent of 995 g / eq, and a solid content of 60 mass %.

[0115] [Production Example D-1] Production of Defoamer (d-1) 100 parts of xylene was charged into a 1000 ml reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer and a nitrogen gas inlet. The reaction vessel was heated to 90° C. while introducing nitrogen gas, and the following solution was dropped at a constant rate over 90 minutes using a dropping funnel. One hour after the dropwise addition, 1.5 parts of a polymerization initiator (t-butylperoxy-2-ethylhexanoate) was added, and the reaction was continued for 3 hours while maintaining the temperature at 90° C. After the reaction was completed, the solid content was adjusted to 30% with xylene, and a defoaming agent having a structural unit derived from alkyl (meth)acrylate was obtained. The number average molecular weight of the obtained 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 Defoamer (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 Defoamer (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 defoamer (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 defoamer (d-5) 200 parts of xylene was 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 dropped at a constant rate over 90 minutes using a dropping funnel. One hour after the dropwise addition, 1.5 parts of a polymerization initiator (t-butylperoxy-2-ethylhexanoate) was added, and the reaction was continued for 3 hours while maintaining the temperature at 90° C. After the reaction was completed, the solid content was adjusted to 30% with xylene to obtain a defoamer (d-5) having a structural unit derived from alkyl (meth)acrylate. The number average molecular weight of the obtained defoamer 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 defoamer (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 defoamer (d-7) A defoaming agent (d-7) having a number average molecular weight of 2.6 million 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 Defoamer (d-8) A defoaming agent (d-8) having a structural unit derived from an 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 defoamer (d-9) 20 parts of polybutadiene and 185 parts of xylene were charged into a 1000 ml reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer and a nitrogen gas inlet. The reaction vessel was heated to 100°C while introducing nitrogen gas, and the following solution was dropped at a constant rate over 4 hours using a dropping funnel. One hour after the dropwise addition, 2.0 parts of a polymerization initiator (t-butylperoxy-2-ethylhexanoate) was added, and the reaction was continued for 2 hours while maintaining the temperature at 100°C. After the reaction was completed, the solid content was adjusted to 30% with xylene to obtain a defoamer (d-9) having a structural unit derived from alkyl (meth)acrylate. The number average molecular weight of the obtained defoamer was 56,000.

[0127] solution Lauryl methacrylate 180 parts Xylene 180 parts 0.8 parts t-butylperoxy-2-ethylhexanoate

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

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

[0130] Polyamine (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: 34.1g / eq Non-alicyclic polyamine (b-2-2): Diethylenetriamine, aliphatic polyamine, manufactured by Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent 20.7g / eq

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

[0132] Anti-rust pigment Product name: 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] The base agent and the curing agent were prepared according to the formulations shown in Tables 1 to 6. The base agent and the curing agent were mixed to prepare anticorrosive coating compositions. The blending amounts in Tables 1 to 6 are mass ratios relative to 100 parts by mass of the solid content of the anticorrosive coating composition.

[0134] (Resistance measurement) The anticorrosive coating composition was spray-coated on a SS400 grid-blasted steel plate and dried at 23° C. for one week to produce a coated plate having a primer coating film of 60 μm in thickness. The coated plate was then 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 of FIG. 1. Next, 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 volume resistivity (Ω cm) was obtained by dividing the wet coating resistance value obtained by the coating thickness of the test piece.

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

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

[0138] (Evaluation Criteria) A: 1.0×10 9 Ω cm 2 End B: 1.0×10 9 Ω cm 2 less than

[0139] (2) Appearance The anticorrosive coating composition was spray-painted onto a SS400 grid-blasted steel plate in a low-temperature environment (0°C) where it is difficult to obtain an antifoaming effect, and 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 are visible B2: Cracks are observed

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

[0142] (Evaluation Criteria) 4: The coating will not shift even if you press it hard with your finger. 3: The coating shifts when pressed firmly with a finger, but no marks are left when rubbed lightly. 2: When I rub it lightly with my finger, it leaves a mark, but when I touch it lightly, no paint comes off. 1: Paint comes off when you lightly touch it with your finger

[0143] (4) Corrosion resistance The anticorrosive coating composition immediately after preparation was applied to a grid-blasted steel plate (7 cm × 15 cm × 3.2 mm) using an air spray so that the dry film thickness was approximately 60 μm, and the plate was cured for 7 days under conditions of 23°C and 50% RH to produce three coated plates with a primer coating. Two cuts, each 80 mm long and 0.1 mm wide and deep enough to reach the object to be coated, were made in the primer coating using a cutter, at a 60° angle to each other 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 combined cyclic corrosion tester (manufactured by Suga Test Instruments Co., Ltd., Model CCT-1) was used in D mode to carry out an accelerated corrosion test of 120 cycles.

[0145] In the CCT test, one cycle consisted of three steps: (1) spraying a 50±10 g / L sodium chloride aqueous solution in an environment of 30±2°C for 30 minutes, (2) wetting in a humid environment of 30±2°C temperature and 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 one side of the cut 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 film obtained from the anticorrosive coating composition was evaluated according to JIS K5600-5-6. In detail, the anticorrosive coating composition was applied to a Zn-plated steel sheet (150×70×3.2 mm) that had been exposed outdoors for 6 months, using an air spray to a dry film thickness of about 60 μm, and then cured for 7 days under conditions of 23°C and 50% RH. Furthermore, the coating was left to stand for 7 days under conditions of 50°C and 95% RH to obtain a test coating film. With reference to JIS K 5600-5-6 "7. Procedure", six cuts were made in each direction of the test coating film at 2 mm intervals. An adhesive tape was pressed onto the cut surface and peeled off. The obtained coating surface was visually observed and classified according to Table 1 in 8.3 of JIS K 5600-5-6. The classification was evaluated according to the following criteria. A rating of 3 or 4 can be evaluated as excellent adhesion.

[0149] (Evaluation Criteria) 4: Class 0 or Class 1 3: Classification 2 2: Classification 3 1: Category 4 or Category 5

[0150] (6) Recoatability The coating film obtained from the anticorrosive coating composition was evaluated with reference to JIS K 5551:2018 7.11 Topcoat compatibility. In detail, the anticorrosive coating composition was applied to a bonded steel plate (150 mm x 70 mm x 0.8 mm) using a brush so that the dry film thickness was about 60 μm, and 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 over the test coating film using a brush. Evaluation items were set from the viewpoints of workability when applying the topcoat paint and resolubility of the test coating film, and the overcoatability was evaluated according to the following criteria. A rating of 3 or 4 can be evaluated as excellent overcoatability.

[0151] (Evaluation items) i: Paint workability: Does the brush feel heavy? ii: Redissolution: Whether the test coating film is dissolved or not iii: Redissolving ability: Is lifting occurring?

[0152] (Evaluation Criteria) 4: None of the above items are problematic. 3: There is a problem with one of the above items. 2: There is a problem with two of the above items. 1: There are problems with all of the above items.

[0153] (7) Stepping ability The anticorrosive coating composition was applied to a bonded steel plate (900 x 225 x 0.8 mm) using an air spray so that the dry film thickness was about 60 μm, and the coating was 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 stepping property was evaluated according to the following criteria. A rating of 3 or 4 can be evaluated as excellent stepping property. JP 2010-24408 A can be referred to for the method of evaluating stepping property.

[0154] (Evaluation Criteria) 4: The coating does not leave shoe marks. 3: The coating does not leave shoe marks, but is sticky. 2: It is sticky and leaves shoe marks on the coating. 1: Paint gets on the soles of your shoes.

[0155] (8) Shrinkage resistance An alkyd resin paint (product name: Quick Dry PZ Helgon Eco, manufactured by Nippon Paint Co., Ltd.) was applied to a hot-dip galvanized steel plate (150 x 70 x 3.2 mm) using a brush so that the dry film thickness was about 60 μm, and dried for one day under conditions of 23 ° C. and 50% RH. Next, an anticorrosive coating composition was applied to a hot-dip galvanized steel plate (150 x 70 x 3.2 mm) using a brush so that the dry film thickness was about 50 μm, and dried for one day under conditions of 23 ° C. and 50% RH. The shrink 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 shrink resistance.

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

[0157] (9) Thermal cycling resistance The thermal cycling resistance of the coating film obtained from the anticorrosive coating composition was evaluated with reference to JIS-K-5600-7-4. In detail, the anticorrosive coating composition was applied to a bonded steel plate (150 mm x 70 mm x 0.8 mm) using a brush so that the dry film thickness was about 60 μm, and the coating was aged for 16 hours at 23°C and 50% RH to obtain a test coating film. A topcoat paint (product name: Hi-Pon 30 Fine intermediate coating, manufactured by Nippon Paint Co., Ltd.) was applied to the test coating film using a brush, and the coating was aged for 7 days at 23°C and 50% RH. The obtained multilayer coating film was subjected to 50 cycles of hot and cold cycle testing, with one cycle being 18 hours at 23±2°C, 3 hours at -20°C, and 3 hours at 50±3°C. After 50 cycles, the hot and cold cycle resistance was evaluated according to the following evaluation criteria. A rating of 3 or 4 can be evaluated as excellent in hot and cold cycle resistance.

[0158] (Evaluation Criteria) 4: No abnormalities in appearance 3: Cracks occur in less than 10% of the area 2: Cracks occur in less than 50% of the area 1: Cracks occur all over the surface

[0159] [Table 1]

[0160] [Table 2]

[0161] [Table 3]

[0162] [Table 4]

[0163] [Table 5]

[0164] [Table 6] [Industrial Applicability]

[0165] According to the present invention, there is provided an anticorrosive coating composition having excellent anticorrosive properties. The anticorrosive coating composition is particularly suitable for use as an undercoat coating for steel materials used in large structures such as plants, bridges, steel towers, and buildings. [Explanation of symbols]

[0166] 10 Resistance measuring device 1 Temperature bath 2. Ion-exchanged water 3 Platinum electrode 4 Painted board 5 High resistance measuring device 6 Temperature Sensor 7 Thermometer

Claims

1. An anticorrosive coating composition comprising a base agent (I) and a curing agent (II), The base material (I) contains an epoxy resin (a), The epoxy resin (a) contains at least one of a bisphenol A type epoxy resin (a-11) and a novolac type epoxy resin (a-12) having a weight average molecular weight of 6,000 or more and 12,000 or less, The curing agent (II) contains a polyamine (b) and an alkylphenol (c), 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) not having a cyclic aliphatic hydrocarbon group to which an amino group is bonded, At least one of the base agent (I) and the curing agent (II) 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 contains a vinyl-based defoaming agent (d) having 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; the content of the alicyclic polyamine (b-1) is 30% by mass or more and 80% by mass or less of the solid content of the curing agent (II), the content of the non-alicyclic polyamine (b-2) is 2% by mass or more and 45% by mass or less of the solid content of the curing agent (II), The 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 vinyl-based defoaming agent (d) is 0.005 parts by mass or more and 3 parts by mass or less per 100 parts by mass of the anticorrosive coating composition.

2. 2. The anticorrosive coating composition according to claim 1, wherein a coating film having a thickness of 60 μm formed from the anticorrosive coating composition has a resistance of 1.0×10 Ω·cm or more after immersion in ion-exchanged water at 35° C. for 24 hours.

3. 3. The anticorrosive coating composition according to claim 1, wherein a coating film formed from the anticorrosive coating composition has a volume resistivity of 1.7×10 Ω·cm or more after immersion in ion-exchanged water at 35° C. for 24 hours.

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

5. 3. The anticorrosive coating composition according to claim 1, wherein the base component (I) further comprises a silane coupling agent (e) having at least one of a trimethoxysilyl group and a triethoxysilyl group.

6. The anticorrosive coating composition according to claim 1 or 2, further comprising a weak solvent (f).

7. The base material (I) further contains a pigment (g), 3. The anticorrosive coating composition according to claim 1, wherein the pigment volume concentration of the main component (I) is from 25% by volume to 55% by volume.

8. A metal substrate, A coated article comprising a primer coating film formed on the substrate from the anticorrosive coating composition according to claim 1 or 2.