Anticorrosion coating composition

Abstract

To provide an anticorrosive coating composition capable of forming a coating film having excellent corrosion resistance and excellent adhesion to other coating films even in a case where intervals between multiple coating processes are long.SOLUTION: There is provided an anticorrosive coating composition, in which a main agent (I) contains an epoxy resin (a) the epoxy resin (a) including a modified novolac-type epoxy resin (a-1) that has at least one functional group selected from the group consisting of a hydroxy group, a phenolic hydroxy group, and a carboxy group in an amount of 0.06 mol / kg or more, and a novolac-type epoxy resin (a-2) that does not have the functional group or has the functional group in an amount of less than 0.06 mol / kg, and a curing agent (II) contains a polyamine (b) and an alkylphenol (c), the polyamine (b) including an alicyclic polyamine (b-1) and a non-alicyclic polyamine (b-2).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a corrosion-preventive coating composition. [Background technology]

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

[0003] [Patent Document 1] Patent No. 6832122 [Overview of the project] [Problems that the invention aims to solve]

[0004] The coating obtained using the coating composition described in Patent Document 1 does not have sufficient adhesion to other coatings when the interval between coating processes is long.

[0005] The present invention aims to provide a corrosion-resistant coating composition that yields a coating film with excellent corrosion resistance and excellent adhesion to other coatings even when there is a long interval between multiple coating processes. [Means for solving the problem]

[0006] The present invention provides the following embodiments. [1] It contains a main component (I) and a hardening agent (II), The main component (I) comprises epoxy resin (a), The epoxy resin (a) is A modified novolac-type epoxy resin (a-1) having at least one functional group selected from the group consisting of hydroxyl groups, phenolic hydroxyl groups, and carboxyl groups at a concentration of 0.06 mol / kg or more, and having a weight-average molecular weight of 3000 to 12000, The present invention comprises a novolac-type epoxy resin (a-2) which either does not have the aforementioned functional group or has less than 0.06 mol / kg of it, and has a weight-average molecular weight of 5000 or more and 12000 or less, The curing agent (II) comprises 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. The solid content of the alicyclic polyamine (b-1) is 30% by mass or more and 90% by mass or less of the solid content of the curing agent (II). The solid 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 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). A corrosion-preventive coating composition wherein the solid content of the modified novolac-type epoxy resin (a-1) is 5 parts by mass or more and 70 parts by mass or less, based on 100 parts by mass of the total solid content of the epoxy resin (a). [2] The anticorrosive coating composition according to [1] above, wherein the ratio 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) (amount of active hydrogen groups / amount of epoxy groups) is 0.8 or more and 1.2 or less. [3] The modified novolac-type epoxy resin (a-1) is the anticorrosive coating composition according to [1] or [2] above, wherein the novolac-type epoxy resin is chain-extended by a chain-like aliphatic group-containing dicarboxylic acid. [4] The coating film with a thickness of 60 μm formed by the aforementioned anticorrosive coating composition has a coating film resistance value of 1.0 × 10⁻¹⁰ after being immersed in ion-exchanged water at 35°C for 24 hours. 9Ω·cm 2 The anticorrosive paint composition of the above [1] or [2] as described above. [5] The non-alicyclic polyamine (b-2) in the anticorrosive paint composition of the above [1] or [2] contains at least one selected from the group consisting of a chain aliphatic polyamine, a polyamine having an aromatic hydrocarbon group, and a polyamine having a heterocyclic ring. [6] Furthermore, the anticorrosive paint composition of the above [1] or [2] containing a weak solvent (e). [7] Furthermore, it contains a pigment (f), In the anticorrosive paint composition, the pigment volume concentration is 25% by volume or more and 50% by volume or less, and it is the anticorrosive paint composition of the above [1] or [2]. [8] A metal object to be painted, On the object to be painted, there is a primer coating film formed by the anticorrosive paint composition of the above [1] or [2], and it is a painted article. [9] Furthermore, adjacent to the primer coating film, there is another coating film formed by a paint composition containing at least one selected from the group consisting of a polyol, a polyisocyanate, an epoxy resin, and a polyamine, and it is the painted article of the above [8].

Advantages of the Invention

[0007] According to the present invention, there is provided an anticorrosive paint composition capable of obtaining a coating film that is excellent in anticorrosion performance and excellent in adhesion to other coating films even when the interval between multiple coating steps is long.

Brief Description of the Drawings

[0008] [Figure 1] It is an explanatory diagram showing an overview of an apparatus for measuring a resistance value. [Figure 2] It is a graph showing a change in an applied voltage when measuring a resistance value.

Modes for Carrying Out the Invention

[0009] <00001[Corrosion-preventive coating composition] The anticorrosive coating composition of this disclosure comprises a main component (I) and a hardening agent (II).

[0010] The main component (I) includes epoxy resin (a). Epoxy resin (a) includes a modified novolac-type epoxy resin (a-1) having at least one functional group selected from the group consisting of hydroxyl groups, phenolic hydroxyl groups, and carboxyl groups in a concentration of 0.06 mol / kg or more, and a weight-average molecular weight of 3000 to 12000, and a novolac-type epoxy resin (a-2) having neither the above-mentioned functional group nor having less than 0.06 mol / kg of it, and a weight-average molecular weight of 5000 to 12000.

[0011] The curing agent (II) comprises a polyamine (b) and an alkylphenol (c). Polyamine (b) includes alicyclic polyamines (b-1) having a cyclic aliphatic hydrocarbon group to which an amino group is attached, and non-alicyclic polyamines (b-2) that do not have a cyclic aliphatic hydrocarbon group to which an amino group is attached.

[0012] The solid content of alicyclic polyamine (b-1) is 30% to 90% by mass of the solid content of curing agent (II). The solid content of non-alicyclic polyamine (b-2) is 2% to 45% by mass of the solid content of curing agent (II). The solid content of alkylphenol (c) is 5% to 60% by mass of the solid content of curing agent (II).

[0013] The solid content of the modified novolac-type epoxy resin (a-1) is 5 parts by mass or more and 70 parts by mass or less, based on 100 parts by mass of the total solid content of epoxy resin (a).

[0014] A decrease in corrosion resistance is partly due to the penetration of corrosive factors (e.g., water, oxygen, chloride ions) into the coating. Improving the function of blocking corrosive factors (blocking ability) increases corrosion resistance and also increases the electrical resistance of the coating.

[0015] This disclosure uses a novolac-type epoxy resin (a-2) which has a relatively high molecular weight and readily forms a planar structure. In addition, a larger amount of alicyclic polyamine (b-1), which also readily forms a planar structure, is used as a curing agent. As a result, the coating film (primer coating film) formed by the anticorrosive coating composition of this disclosure becomes denser and its barrier properties are improved.

[0016] Anticorrosion coating compositions are typically used as a primer. For large structures such as ships, bridges, buildings, tanks, and plants, one or more coatings are formed on top of the primer coating. When multiple coatings are formed on large structures, long intervals (painting intervals) usually occur between painting processes. During this time, the primer coating is exposed to ultraviolet light and deteriorates. Subsequently formed coatings have difficulty adhering to a deteriorated primer coating. Hereinafter, the primer coating is used as the reference point, and coatings positioned adjacent to and above the primer coating are referred to as "other coatings."

[0017] In this disclosure, a modified novolac-type epoxy resin (a-1) having at least one functional group selected from the group consisting of hydroxyl groups, phenolic hydroxyl groups, and carboxyl groups is further used in combination in a specific proportion. The above functional group reacts with various groups contained in other coating films to enhance adhesion between coating films. Therefore, even when there is a long interval between multiple coating processes, the adhesion between the primer coating film and other coating films is improved.

[0018] A long interval refers to a situation where, for example, there is a gap of about 10 days. Hereinafter, the adhesion between coatings when there is a long interval between the primer coating process and the coating process of other coatings will be referred to as interval adhesion.

[0019] High adhesion between coating layers can also contribute to improved corrosion resistance, as it suppresses the penetration of corrosive factors between the coating layers.

[0020] Below, epoxy equivalent is determined based on the solid content mass. Epoxy equivalent is determined in accordance with JIS K 7236:2001.

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

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

[0023] The amounts of hydroxyl groups, phenolic hydroxyl groups, and carboxyl groups can be quantified in accordance with JIS K 0070.

[0024] The amounts of hydroxyl groups, phenolic hydroxyl groups, and carboxyl groups can also be calculated by dividing the acid value of the modified novolac-type epoxy resin (a-1) by the molecular weight of KOH (56.11). For example, the amounts of hydroxyl groups, phenolic hydroxyl groups, and carboxyl groups in a modified novolac-type epoxy resin (a-1) with an acid value of 5.0 KOH mg / g are 5.0 (KOH mg / g) / 56.11 = 0.089 mmol / g = 0.089 mol / kg.

[0025] The solid content of an anticorrosive coating composition is the total components of the anticorrosive coating composition excluding volatile components (typically solvents). The solid content concentration of an anticorrosive coating composition can be calculated from the residue when the anticorrosive coating composition is heated to 140°C, in accordance with JIS K 5601-1-2, the method for measuring residual content upon heating.

[0026] The resin solids of the anticorrosive coating composition are the solids of the epoxy resin (a), polyamine (b), and other resin components contained in the anticorrosive coating composition.

[0027] • Main ingredient (I) The main component (I) contains epoxy resin (a).

[0028] • Epoxy resin (a) The epoxy resin (a) is a film-forming component. The epoxy resin (a) cross-links with the polyamine (b) to form a cured coating film.

[0029] The epoxy resin (a) comprises a modified novolac-type epoxy resin (a-1) having at least one functional group selected from the group consisting of hydroxyl groups, phenolic hydroxyl groups, and carboxyl groups in a concentration of 0.06 mol / kg or more, and an Mw of 3000 to 12000, and a novolac-type epoxy resin (a-2) having neither the above functional group nor having less than 0.06 mol / kg of the above functional group, and an Mw of 5000 to 12000.

[0030] • Modified novolac-type epoxy resin (a-1) Modified novolac-type epoxy resin (a-1) is a novolac-type epoxy resin modified with a compound having at least one functional group selected from the group consisting of hydroxyl groups, phenolic hydroxyl groups, and carboxyl groups.

[0031] Examples of the novolac-type epoxy resin used as the base material (raw epoxy resin) include phenol novolac type, cresol novolac type, and bisphenol A novolac type. The raw epoxy resin may be a modified form having functional groups other than those mentioned above.

[0032] Modified novolac-type epoxy resin (hereinafter abbreviated as modified epoxy resin) (a-1) can be prepared by conventionally known methods. Modified epoxy resins containing hydroxyl groups can be obtained, for example, by reacting a raw epoxy resin with a compound containing a hydroxyl group. Examples of compounds containing hydroxyl groups include diethanolamine and di-2-propanolamine.

[0033] Modified epoxy resins having carboxyl groups can be obtained, for example, by reacting a raw epoxy resin with a dicarboxylic acid. Examples of dicarboxylic acids include adipic acid and 1,10-decanedicarboxylic acid.

[0034] Modified epoxy resins having phenolic hydroxyl groups can be obtained, for example, by reacting a raw epoxy resin with a phenol having an amino group. Examples of phenols having an amino group include 4-aminophenol and 3-aminophenol.

[0035] A commercially available example of a novolac-type modified epoxy resin (a-1) is the trade name "HARIPOL EP497" (weight-average molecular weight 7900, solid content 60% by mass, epoxy equivalent 750 g / eq, functional group content 0.09 mol / kg, manufactured by Harima Chemicals Co., Ltd.). The above resin has phenolic hydroxyl groups.

[0036] The amount of functional groups in the modified epoxy resin is 0.06 mol / kg or more, may be 0.10 mol / kg or more, may be 0.25 mol / kg or more, or may be 0.4 mol / kg or more. In order to design a high initial electrical resistance value for the coating film, the amount of functional groups may be 1.25 mol / kg or less, may be 1.0 mol / kg or less, may be 0.8 mol / kg or less, or may be 0.5 mol / kg or less.

[0037] The Mw of the modified epoxy resin (a-1) is between 3000 and 12000. When the Mw of the modified epoxy resin (a-1) is 3000 or higher, the decrease in barrier properties can be suppressed. When the Mw of the modified epoxy resin (a-1) is 12000 or lower, the impact resistance is improved. The Mw of the modified epoxy resin (a-1) may be 4500 or higher, 7500 or higher, or 8000 or higher. The Mw of the modified epoxy resin (a-1) may be 11000 or lower, 10000 or lower, or 9000 or lower.

[0038] The solid content of the modified epoxy resin (a-1) is, for example, 1.6% by mass or more and 29.0% by mass or less of the solid content of the anticorrosive coating composition. When the above content of the modified novolac-type epoxy resin (a-1) is 1.6% by mass or more, interval adhesion can be further improved. When the above content of the modified novolac-type epoxy resin (a-1) is 29.0% by mass or less, the relative proportion of the novolac-type epoxy resin (a-2) in the coating film increases, and thus corrosion resistance can be further improved. The above content of the modified novolac-type epoxy resin (a-1) may be 2.5% by mass or more, or 5.0% by mass or more. The above content of the modified novolac-type epoxy resin (a-1) may be 25.0% by mass or less, or 20.0% by mass or less, or 15.0% by mass or less.

[0039] The solid content of the modified epoxy resin (a-1) is 5 parts by mass or more and 70 parts by mass or less per 100 parts by mass of the total solid content of the epoxy resin (a). When the above content of the modified epoxy resin (a-1) is 5 parts by mass or more, interval adhesion is improved. When the above content of the modified epoxy resin (a-1) is 70 parts by mass or less, the relative proportion of the novolac-type epoxy resin (a-2) in the coating film increases, so the coating film resistance value increases and corrosion resistance may be further improved. The above content of the modified epoxy resin (a-1) may be 10.0 parts by mass or more, 15.0 parts by mass or more, 18.0 parts by mass or more, or 20.0 parts by mass or more. The above content of the modified epoxy resin (a-1) may be 60.0 parts by mass or less, 50.0 parts by mass or less, or 40.0 parts by mass or less.

[0040] The epoxy equivalent of the modified epoxy resin (a-1) may be 700 g / eq or more and 6000 g / eq or less, in that it enhances curability. The epoxy equivalent of the modified epoxy resin (a-1) may be 900 g / eq or more, 1000 g / eq or more, or 1100 g / eq or more. In particular, in that it enhances curability at low temperatures (e.g., below 5°C), the epoxy equivalent of the modified epoxy resin (a-1) may be 4000 g / eq or less, 3500 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.

[0041] The modified epoxy resin (a-1) may have its chain extended by utilizing the reaction of epoxy groups with active hydrogen-containing compounds that can react with epoxy groups. Examples of active hydrogen-containing compounds include difunctional compounds such as linear aliphatic group-containing dicarboxylic acids, diamines, and polyether polyols.

[0042] The modified epoxy resin (a-1) may be chain-extended by a dicarboxylic acid containing a linear aliphatic group. This introduces a flexible portion (hydrocarbon group) into the rigid planar structure formed by the aromatic ring, improving the impact resistance of the primer coating. In addition, carboxyl groups are also introduced into the raw material novolac-type epoxy resin.

[0043] The linear aliphatic group may be saturated or unsaturated. The linear aliphatic group may be linear or branched. Examples of dicarboxylic acids containing linear aliphatic groups include polymerized fatty acids such as dimer acids. Polymerized fatty acids are typically dimers of fatty acids produced by polymerization reactions of unsaturated fatty acids. The starting fatty acids are, for example, long-chain fatty acids with 13 to 21 carbon atoms. A typical example of a dimer acid is a dibasic acid with 36 carbon atoms obtained by polymerization of an unsaturated fatty acid with 18 carbon atoms.

[0044] The raw material novolac-type epoxy resin and the above-mentioned dicarboxylic acid are reacted such that the molar ratio of epoxy groups to carboxyl groups (epoxy groups:carboxyl groups) of the raw material novolac-type epoxy resin is, for example, 1:0.03 to 1:0.3.

[0045] In the chain extension step, a diol may be used along with the dicarboxylic acid. This is expected to suppress gelation of the reaction system. Examples of diols include aliphatic diols such as ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, or 1,6-hexanediol; alicyclic diols such as 1,2-cyclohexanediol or 1,4-cyclohexanediol; aromatic diols such as bisphenol A, bisphenol F, resorcinol, or hydroquinone; bifunctional polyether polyols such as polyoxyethylene glycol, polyoxypropylene glycol, or polyoxytetramethylene glycol, and random or block copolymers thereof; and bifunctional polyester polyols such as bifunctional polyester polyols obtained by esterification of the above diol or polyol with a polycarboxylic acid or its anhydride, or bifunctional polycaprolactone polyols obtained by polymerization of the above polyol with caprolactone. These can be used individually or in combination of two or more.

[0046] • Novolac-type epoxy resin (a-2) The novolac-type epoxy resin (a-2) either does not have the above-mentioned functional groups or has them in amounts less than 0.06 mol / kg. Further improvement in the initial electrical resistance of the coating film can be expected with the functional group-free novolac-type epoxy resin (hereinafter referred to as the functional group-free epoxy resin) (a-2).

[0047] Examples of functional group-free epoxy resins (a-2) include phenol novolac type, cresol novolac type, and bisphenol A novolac type.

[0048] The amount of functional groups in the functional group-free epoxy resin (a-2) is less than 0.06 mol / kg, may be 0.05 mol / kg or less, may be 0.03 mol / kg or less, or may be 0 mol / kg.

[0049] The Mw of the functional group-free epoxy resin (a-2) is between 5000 and 12000. When the Mw of the functional group-free epoxy resin (a-2) is 5000 or higher, the barrier against corrosive factors is improved. When the Mw of the functional group-free epoxy resin (a-2) is 12000 or lower, the impact resistance is improved. The Mw of the functional group-free epoxy resin (a-2) may be 6000 or higher, or 8000 or higher. The Mw of the functional group-free epoxy resin (a-2) may be 10000 or lower, or 9000 or lower.

[0050] The solid content of the functional group-free epoxy resin (a-2) is, for example, 10% by mass or more and 40% by mass or less of the solid content of the anticorrosive coating composition. When the above content of the functional group-free epoxy resin (a-2) is 10% by mass or more, the corrosion resistance may be further improved. When the above content of the functional group-free epoxy resin (a-2) is 40% by mass or less, the relative proportion of the modified epoxy resin (a-1) in the coating film increases, and interval adhesion may be further improved. The above content of the functional group-free epoxy resin (a-2) may be 14.0% by mass or more, or 20.0% by mass or more. The above content of the functional group-free epoxy resin (a-2) may be 38.0% by mass or less, 35.0% by mass or less, 30.0% by mass or less, or 25.0% by mass or less.

[0051] The epoxy equivalent of the functional group-free epoxy resin (a-2) may be 1000 g / eq or more and 1200 g / eq or less, in that it enhances curability (especially curability at low temperatures). The epoxy equivalent of the functional group-free epoxy resin (a-2) may be 1010 g / eq or more, and may be 1020 g / eq or more. The epoxy equivalent of the functional group-free epoxy resin (a-2) may be 1150 g / eq or less, and may be 1100 g / eq or less.

[0052] Examples of commercially available epoxy resins without functional groups (a-2) include the product name "EPICLON 5970-60" (phenol novolac type epoxy resin, Mw 9,000, epoxy equivalent 1,000 g / eq or more, functional group content 0 mol / kg, manufactured by DIC Corporation).

[0053] • Other epoxy resins (a-3) The epoxy resin (a) may include other epoxy resins (a-3). Other epoxy resins (a-3) include epoxy resins other than novolac type, novolac type epoxy resins having 0.06 mol / kg or more of functional groups and a weight-average molecular weight of less than 3,000 or greater than 12,000, and novolac type epoxy resins having no functional groups or having less than 0.06 mol / kg of functional groups and a weight-average molecular weight of less than 5,000 or greater than 12,000.

[0054] Examples of epoxy resins other than novolac type include aromatic epoxy resins such as bisphenol type, biphenyl type, and naphthalene type; and aliphatic epoxy resins such as dicyclopentadiene type and glycidyl ethers of polyhydric alcohols. These can be used individually or in combination of two or more types.

[0055] 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 include bisphenol A type, 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 obtained by adding hydrogen to these bisphenol type epoxy resins. These can be used individually or in combination of two or more types.

[0056] The solid content of the other epoxy resin (a-3) may be 10.0 parts by mass or less per 100 parts by mass of the total solid content of epoxy resin (a). The solid content of the other epoxy resin (a-3) may be 8.0 parts by mass or less, 5.0 parts by mass or less, or 0 parts by mass.

[0057] • Hardener (II) The curing agent (II) contains polyamine (b) and alkylphenol (c).

[0058] • Polyamine (b) Polyamine (b) is the curing component. Polyamine (b) crosslinks with epoxy resin (a) to form a cured coating film.

[0059] Polyamine (b) includes alicyclic polyamines (b-1) having cyclic aliphatic hydrocarbon groups to which amino groups are attached, and non-alicyclic polyamines (b-2) that do not have cyclic aliphatic hydrocarbon groups to which amino groups are attached. When alicyclic polyamines (b-1) and non-alicyclic polyamines (b-2) are used in combination, dissolution and lifting of the primer coating are more easily suppressed when other coatings are laminated on top of the primer coating.

[0060] • Alicyclic polyamine (b-1) Examples of alicyclic polyamines (b-1) include 1,4-cyclohexanediamine, 4,4'-methylenebiscyclohexylamine, 4,4'-isopropylidenebiscyclohexylamine, norbornadiamine, bis(aminomethyl)cyclohexane, diaminodicyclohexylmethane, isophoronediamine, mensendiamine (MDA), and 1,3-bis(aminomethyl)cyclohexane. These can be used individually or in combination of two or more.

[0061] 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 properties may be improved. When the active hydrogen equivalent of the alicyclic polyamine (b-1) is 150 g / eq or less, the barrier properties may be improved. The active hydrogen equivalent of the alicyclic polyamine (b-1) may be 32 g / eq or more, or 33 g / eq or more. The active hydrogen equivalent of the alicyclic polyamine (b-1) may be 100 g / eq or less, or 50 g / eq or less.

[0062] The solid content of the alicyclic polyamine (b-1) is 30% by mass or more and 90% by mass or less of the solid content of the curing agent (II). When the above content of alicyclic polyamine (b-1) is 30% by mass or more, curability is particularly improved at low temperatures. When the above content of alicyclic polyamine (b-1) is 90% by mass or less, the tackiness of the resulting coating film is reduced and traction may be improved. The above content of alicyclic polyamine (b-1) may be 32% by mass or more, 50% by mass or more, 70% by mass or more, or 70% by mass or more. The above content of alicyclic polyamine (b-1) may be 85% by mass or less, or 80% by mass or less. Tractionability refers to the performance in which, when a worker walks on the coating film, it is difficult for footprints to be formed on the coating film and peeling of the coating film is minimal.

[0063] • Non-alicyclic polyamines (b-2) Examples of non-alicyclic polyamines (b-2) include linear aliphatic polyamines, polyamines having an aromatic ring to which an amino group is attached (aromatic polyamines), and polyamines having a heterocyclic ring to which an amino group is attached (heterocyclic polyamines). These can be used individually or in combination of two or more.

[0064] Examples of linear aliphatic polyamines include alkylene polyamines and polyalkylene polyamines. Examples of alkylene polyamines include H2N-R 1 -NH2(wherein, R 1is a divalent hydrocarbon group having 1 to 12 carbon atoms, which may be substituted with one or more hydrocarbon groups having 1 to 10 carbon atoms, and may be branched. ) is represented as ). Examples of alkylene polyamines include methylenediamine, ethylenediamine, 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 diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and hexamethylenetetramine. These can be used individually or in combination of two or more.

[0065] Other examples of linear aliphatic polyamines include tetra(aminomethyl)methane, tetrakis(2-aminoethylaminomethyl)methane, 1,3-bis(2'-aminoethylamino)propane, triethylene-bis(trimethylene)hexamine, bis(3-aminoethyl)amine, and bishexamethylenetriamine [H2N(CH2)6NH(CH2)6NH2]. These can be used individually or in combination of two or more.

[0066] 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'-diaminodiphenyl ether, 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 can be used individually or in combination of two or more types.

[0067] Examples of heterocyclic polyamines include N-methylpiperazine [CH3-N(CH2CH2)2NH], morpholine [HN(CH2CH2)2O], 1,4-bis-(8-aminopropyl)-piperazine, piperazine-1,4-diazacycloheptane, 1-(2'-aminoethylpiperazine), 1-[2'-(2''-aminoethylamino)ethyl]piperazine, 1,11-diazacycloeicosane, and 1,15-diazacyclooctacosane. These can be used individually or in combination of two or more.

[0068] The active hydrogen equivalent of non-alicyclic polyamine (b-2) is, for example, 30 g / eq or more and 550 g / eq or less. The active hydrogen equivalent of non-alicyclic polyamine (b-2) may be 32 g / eq or more, and may be 35 g / eq or more. The active hydrogen equivalent of non-alicyclic polyamine (b-2) may be 250 g / eq or less, 100 g / eq or less, and may be 50 g / eq or less.

[0069] The solid content of non-alicyclic polyamine (b-2) is 2% by mass or more and 45% by mass or less of the solid content of curing agent (II). When the above content of non-alicyclic polyamine (b-2) is 2% by mass or more, curability is particularly improved at low temperatures. When the above content of non-alicyclic polyamine (b-2) is 45% by mass or less, the tackiness of the resulting coating film is reduced and the ability to step into it is improved. The above content of non-alicyclic polyamine (b-2) may be 5% by mass or more, or 10% by mass or more. The above content of non-alicyclic polyamine (b-2) may be 30% by mass or less, or 20% by mass or less, or 15% by mass or less.

[0070] The ratio (active hydrogen groups / epoxy groups) of the total amount of epoxy groups in the epoxy resin (a) to the total amount of active hydrogen groups in the polyamine (b) is, for example, 0.8 or more and 1.2 or less. When the ratio (active hydrogen groups / epoxy groups) is 0.8 or more, the curability may be improved. When the ratio (active hydrogen groups / epoxy groups) is 1.2 or less, the excessive increase in reaction sites is suppressed, and the impact resistance of the primer coating may be improved. The ratio (active hydrogen groups / epoxy groups) may be 0.85 or more, or 0.90 or more. The ratio (active hydrogen groups / epoxy groups) may be 1.15 or less, or 1.10 or less.

[0071] The amount of active hydrogen groups is obtained by dividing the solid content mass (g) of polyamine (b) by the amount of active hydrogen equivalent (g / eq) (solid content mass (g) / active hydrogen equivalent (g / eq)). When multiple types of polyamine (b) are blended, the product of the mass percentage (%) of each polyamine in the total polyamine (b) and the value obtained by dividing the solid content mass (g) of that polyamine by the amount of active hydrogen equivalent (g / eq) is calculated, and the sum of these products is the amount of active hydrogen groups.

[0072] The epoxy group weight is obtained by dividing the solid content mass (g) of epoxy resin (a) by the epoxy equivalent (g / eq) (solid content mass (g) / epoxy equivalent (g / eq)). When multiple types of epoxy resin (a) are blended, the product of the mass percentage (%) of each epoxy resin in the total epoxy resin (a) and the value obtained by dividing the solid content mass (g) of that epoxy resin by the epoxy equivalent (g / eq) is calculated. The sum of these products is the epoxy group weight.

[0073] • Alkylphenol (c) The curing agent further contains alkylphenol. Alkylphenol(c) further improves curability (especially low-temperature curability).

[0074] Examples of alkylphenol(c) include monohydric phenols such as methylphenol (o,m,p-cresol), ethylphenol, n-butylphenol, tert-butylphenol, octylphenol, nonylphenol, dodecylphenol, and dinonylphenol. The number of carbon atoms in the alkyl group of alkylphenol(c) is, for example, 1 to 10. The above number of carbon atoms may be 5 or less.

[0075] The solid content of alkylphenol (c) is 5% by mass or more and 60% by mass or less of the solid content of curing agent (II). The above content of alkylphenol may be 8.0% by mass or more, or 10.0% by mass or more. The above content of alkylphenol may be 40.0% by mass or less, 20.0% by mass or less, or 15.0% by mass or less.

[0076] Pigments The anticorrosive coating composition may contain a pigment. The pigment may be contained in the main component (I), in the hardener (II), or in both. The pigment may be contained in the main component (I). Examples of pigments include those commonly used in coating compositions. Examples of pigments include extender pigments and coloring pigments. These may be used individually or in combination of two or more.

[0077] • Body pigments Examples of extender pigments include talc, clay, calcium carbonate, magnesium carbonate, barium sulfate, silicic acid, silicates, aluminum oxide hydrate, calcium sulfate, gypsum, mica-like iron oxide (MIO), glass flakes, szolite mica, and clarite mica. These can be used individually or in combination of two or more. The content of extender pigments is not particularly limited.

[0078] • Coloring pigments Examples of coloring pigments include titanium dioxide, carbon black, lead white, graphite, zinc sulfide, zinc oxide (zinc oxide), 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 can be used individually or in combination of two or more. The content of coloring pigments is not particularly limited.

[0079] The total content of the various pigments is not particularly limited. For example, the total content of the various pigments is 25% by volume or more and 50% by volume or less as the pigment volume concentration (PVC) in the anticorrosive coating composition. This ensures opacity while suppressing the occurrence of cracking in the coating and a decrease in adhesion. The PVC may be 30% by volume or more, or 35% by volume or more. The PVC may be 45% by volume or less, or 40% by volume or less.

[0080] PVC is the volume percentage (%) of the total solids of the various pigments in the anticorrosive coating composition (a mixture of main component (I) and hardener (II)).

[0081] Other resins The anticorrosive coating composition may contain resins other than epoxy resin (a) and polyamine (b). Examples of other resins include xylene resin, acrylic resin, and polyester resin. These may be used individually or in combination of two or more.

[0082] ·solvent The anticorrosion coating composition may contain a solvent. The solvent may be contained in the main component (I), in the hardener (II), or in both. The solvent content is, for example, 5% by mass or more and 50% by mass or less of the total mass of the anticorrosion coating composition.

[0083] Examples of solvents include those commonly used in the field. Examples of solvents include toluene, xylene, isobutyl alcohol, methyl ethyl ketone, and weak solvent (e). These can be used individually or in combination of two or more.

[0084] The anticorrosion coating composition may contain a weak solvent (e). The content of the weak solvent (e) is, for example, 5% by mass or more and 50% by mass or less of the total mass of the anticorrosion coating composition.

[0085] Weak solvent (e) is an aliphatic hydrocarbon compound. Examples of weak solvent (e) include single-component systems such as n-butane, n-hexane, n-heptane, n-octane, isononane, n-decane, n-dodecane, cyclopentane, cyclohexane, and cyclobutane; and mixed systems such as mineral spirits, white spirits, mineral turpentine, isoparaffin, solvent kerosene, aromatic naphtha, VM&P naphtha, and solvent naphtha. These can be used individually or in combination of two or more.

[0086] Examples of commercially available weak solvents (e) include "Solvesso 100," "Solvesso 150," and "Solvesso 200" (all brand names, manufactured by Esso Petroleum Co., Ltd.), and "Swazol 310," "Swazol 1000," and "Swazol 1500" (all brand names, manufactured by Cosmo Oil Co., Ltd.).

[0087] ·others The anticorrosion coating composition may contain other components. Examples of other components include silane coupling agents and various additives. These other components may be contained in the main component (I), in the hardener (II), or in both.

[0088] Silane coupling agents improve the adhesion between the primer coating and the metal substrate. Silane coupling agents may have at least one of a trimethoxysilyl group and a triethoxysilyl group. The content of the silane coupling agent may be 0.5% by mass or more and 5% by mass or less based on the total mass of the anticorrosive coating composition. The silane coupling agent may be included in the main component (I).

[0089] Examples of additives include anti-sagging agents, anti-settling agents, anti-color separation agents, defoaming agents, anti-scalding agents, leveling agents, matting agents, and rust inhibitors. These can be used individually or in combination of two or more.

[0090] ·Preparation method Anticorrosive coating compositions are prepared by mixing a main component, a hardener, and, if necessary, diluents, etc., in a manner known to those skilled in the art. For mixing, commonly used mixing devices such as paint shakers and mixers are used. The mixing of the main component and the hardener is usually performed immediately before use (for example, within 60 minutes after mixing each component). The solvents mentioned above can also be used as examples of diluents.

[0091] The main component is prepared by mixing the above components in the manner described above. The method for preparing the hardening agent is the same.

[0092] [Painted items] The painted article according to this disclosure comprises a metallic object to be painted and a primer coating film formed on the object to be painted with the above-mentioned anticorrosive paint composition.

[0093] • Painting method The anticorrosion coating composition is applied by common methods such as brushes, rollers, and sprays. The same applies to the intermediate coat, topcoat, and combined intermediate and topcoat coating compositions described later.

[0094] ·Object to be coated The object to be coated with the anticorrosive coating composition is not particularly limited as long as corrosion resistance is required. Typically, the object to be coated is a metal. Examples of metals include iron, copper, aluminum, tin, zinc, or alloys thereof.

[0095] Specifically, examples of metal objects to be coated include cold-rolled steel sheets, hot-rolled steel sheets, stainless steel, electro-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 specifically, examples of objects to be coated include ships, vehicles (e.g., railway cars, heavy vehicles), aircraft, bridges, offshore structures, plants, tanks (e.g., oil tanks), pipes, steel pipes, cast iron pipes, steel structures, and buildings.

[0096] The object to be coated may have undergone blast treatment, rust-preventive coating, shop primer coating, or organic or inorganic zinc-rich primer coating. The object to be coated may have a previous coating (a coating other than the primer coating that was formed before the above-mentioned primer coating was formed).

[0097] Primer Paint Princess The anticorrosion coating composition forms a primer coating film with excellent corrosion resistance. The thickness of the primer coating film is not particularly limited and can be set appropriately depending on the type of object to be coated, its application, etc. The dry film thickness of the primer coating film is, for example, 10 μm to 300 μm. The anticorrosion coating composition may be applied multiple times to form a layered primer coating film.

[0098] The resistance value (hereinafter referred to as the wet coating resistance value) of a 60 μm thick primer coating after immersion in ion-exchanged water at 35°C for 24 hours is 1.0 × 10⁻⁶. 9 Ω·cm 2 It could be more than 1.0 × 10 9 Ω·cm 2The coating film having the above wet film resistance value has very high corrosion resistance. The above wet film resistance value can be 1.0×10 10 Ω·cm 2 or more, and can be 1.0×10 11 Ω·cm 2 or more.

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

[0100] The wet film resistance value and the volume resistance value are calculated as follows. On an SS400 grid blast steel plate, the anticorrosive paint composition is applied so that the dry film thickness becomes 60 μm, and dried at 23°C for 1 week to produce a painted plate. The obtained painted plate is immersed in ion-exchanged water in a constant temperature bath at 35°C for 24 hours.

[0101] Thereafter, the platinum electrode 3 and the painted plate 4 are immersed in the ion-exchanged water 2 of the 35°C constant temperature bath 1 of the resistance value measuring device 10 in FIG. 1 to form a circuit with the platinum electrode 3 and the painted plate 4 as electrodes. For the measurement of the resistance value, a high resistance measuring device 5 (for example, the high resistance measuring device B2985A manufactured by Keysight Technologies) is used. The evaluation area of the painted plate 4 is the area of a circle with a diameter of 1 cm. The temperature of the constant temperature bath 1 is measured by the temperature sensor 6 and the thermometer 7.

[0102] A voltage of ±0.5(V) is applied between the electrodes with a voltage change interval of 60 seconds (see Figure 2), and the current value is recorded every 60 seconds. The absolute values ​​of the difference in 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 the formula, V is the voltage difference, which is 1(V). The obtained resistance value is multiplied by the evaluation area to obtain the wet coating resistance value (Ω·cm). 2 The wet coating resistance value obtained is obtained by dividing the obtained wet coating resistance value by the coating thickness of the test piece.

[0103] Other coatings Other coatings may be provided adjacent to the primer coating. That is, a painted article may comprise a workpiece, a primer coating formed on the workpiece, and other coatings formed adjacent to the primer coating. Specific examples of other coatings include an intermediate coating, a topcoat, and a coating that serves both as an intermediate and topcoat.

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

[0105] The thickness of the other coatings is not particularly limited and can be set appropriately depending on the type of object to be coated, its application, etc. The dry film thickness of the other coatings is, for example, 20 μm to 80 μm. The paint composition may be applied multiple times to form other coatings with a layered structure.

[0106] • Third coating A third coating film may be formed on top of another coating film. The third coating film is provided adjacent to the other coating film. 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, 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 functions against pollutants, and antifouling paints that prevent the adhesion of marine organisms. [Examples]

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

[0109] [Manufacturing Example i] Manufacturing of raw epoxy resin (i) In a 2L reactor equipped with a thermometer, stirrer, and condenser, along with a water separator, 250g of p-tert-butylphenol novolac resin (product name: Hitanol #1133, manufactured by Hitachi Chemical Co., Ltd.), 250g of octylphenol novolac resin (product name: Hitanol #1501, manufactured by Hitachi Chemical Co., Ltd.), and 1040g of epichlorohydrin were charged and stirred to form a homogeneous solution. Next, 268g of 48% by mass sodium hydroxide was added dropwise at 60-110°C over 2 hours. During this time, the water generated in the system was removed from the system by azeotrope with the epichlorohydrin using the water separator, while the epichlorohydrin was refluxed in the system. After the dropwise addition was complete, the system was aged at 100-120°C for 2 hours, and the reaction was terminated when the theoretical amount of water had been drained.

[0110] To the epichlorohydrin solution of the obtained epoxy compound, 150 g of xylene was added and washed with a large amount of water. After removing the generated sodium chloride and excess sodium hydroxide, the mixture was neutralized with a 3% by mass aqueous phosphoric acid solution. Then, the epichlorohydrin and xylene were removed by distillation under reduced pressure, and 460 g of a high-boiling point paraffinic solvent (trade name: Swazole 310, manufactured by Cosmo Oil Co., Ltd.) was added to obtain liquid raw material epoxy resin (i). The raw epoxy resin (i) had a Mw of 9500, an epoxy equivalent of 1020 g / eq, a functional group content of 0 mol / kg, and a solids content of 60% by mass.

[0111] [Manufacturing Example ii] Manufacturing of raw epoxy resin (ii) Raw epoxy resin (ii) was obtained in the same manner as in production example i, except that the amount of epichlorohydrin added was changed to 870 g. The Mw of raw epoxy resin (ii) was 10100, the epoxy equivalent was 1025 g / eq, the functional group content was 0 mol / kg, and the solid content was 60% by mass.

[0112] [Manufacturing Example iii] Manufacturing of raw epoxy resin (iii) The raw epoxy resin (iii) was obtained in the same manner as in production example i, except that the amount of epichlorohydrin added was changed to 250 g. The raw epoxy resin (iii) had a Mw of 12000, an epoxy equivalent of 1035 g / eq, a functional group content of 0 mol / kg, and a solid content of 60 mass%.

[0113] [Manufacturing Example iv] Manufacturing of raw epoxy resin (iv) The raw epoxy resin (iv) was obtained in the same manner as in production example i, except that the amount of epichlorohydrin added was changed to 3400 g. The raw epoxy resin (iv) had a Mw of 2400, an epoxy equivalent of 970 g / eq, a functional group content of 0 mol / kg, and a solid content of 60 mass%.

[0114] [Manufacturing Example v] Manufacturing of raw epoxy resin (v) The raw epoxy resin (v) was obtained in the same manner as in production example i, except that the amount of epichlorohydrin added was changed to 2700 g. The raw epoxy resin (v) had a Mw of 4550, an epoxy equivalent of 985 g / eq, a functional group content of 0 mol / kg, and a solid content of 60 mass%.

[0115] [Manufacturing Example vi] Manufacturing of raw epoxy resin (vi) The raw epoxy resin (vi) was obtained in the same manner as in production example i, except that the amount of epichlorohydrin added was changed to 1440 g. The raw epoxy resin (vi) had a Mw of 8500, an epoxy equivalent of 1010 g / eq, a functional group content of 0 mol / kg, and a solid content of 60 mass%.

[0116] [Functional group-free epoxy resin (a-2-1)] The raw epoxy resin (i) obtained above was used as is as a functional group-free epoxy resin (a-2-1).

[0117] [Manufacturing Example 1-2] Manufacturing of Functional Group-Free Epoxy Resin (a-2-2) 200 g of the raw epoxy resin (vi) obtained above was charged into a 2 L reactor, 0.53 g of adipic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.15 g of dibutyltin oxide were added, and the mixture was aged at 220°C for 20 minutes, after which it was cooled to 20°C. This yielded a functional group-free epoxy resin (a-2-2).

[0118] [Manufacturing Example 1-3] Manufacturing of Functional Group-Free Epoxy Resin (a-2-3) 200g of the raw epoxy resin (vi) obtained above was charged into a 2L reactor, 1.48g of diethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the reactor was aged at 100°C for 2 hours. This yielded a functional group-free epoxy resin (a-2-3).

[0119] [Manufacturing Example 1-4] Manufacturing of Functional Group-Free Epoxy Resin (a-2-4) 200g of the raw epoxy resin (vi) obtained above was charged into a 2L reactor, 1.1g of 4-aminophenol (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the reactor was aged at 100°C for 2 hours. This yielded a functional group-free epoxy resin (a-2-4).

[0120] [Manufacturing Example 2-1] Manufacturing of Modified Epoxy Resin (a-1-1) 200 g of the raw epoxy resin (ii) obtained above was charged into a 2 L reactor, 9.9 g of adipic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.15 g of dibutyltin oxide were added, and the mixture was aged at 220 °C for 20 minutes, after which it was cooled to 20 °C. This yielded a carboxyl group-containing modified epoxy resin (a-1-1).

[0121] [Manufacturing Example 2-2] Manufacturing of Modified Epoxy Resin (a-1-2) 200g of the raw epoxy resin (v) obtained above was charged into a 2L reactor, 16.3g of 4-aminophenol (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the reactor was aged at 100°C for 2 hours. This yielded a modified epoxy resin (a-1-2) having phenolic hydroxyl groups.

[0122] [Manufacturing Example 2-3] Manufacturing of Modified Epoxy Resin (a-1-3) 200g of the raw epoxy resin (v) obtained above was charged into a 2L reactor, 4.3g of diethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the reactor was aged at 100°C for 2 hours. This yielded a modified epoxy resin (a-1-3) containing hydroxyl groups.

[0123] [Manufacturing Example 2-4] Manufacturing of Modified Epoxy Resin (a-1-4) A modified epoxy resin containing a carboxyl group (a-1-4) was obtained in the same manner as in Production Example 2-1, except that the raw material epoxy resin (v) was used and the amount of adipic acid added was 22.0 g.

[0124] [Manufacturing Example 2-5] Manufacturing of Modified Epoxy Resin (a-1-5) A modified epoxy resin containing phenolic hydroxyl groups (a-1-5) was obtained in the same manner as in Production Example 2-2, except that the raw material epoxy resin (vi) was used and the amount of 4-aminophenol added was 2.3 g.

[0125] [Manufacturing Example 2-6] Manufacturing of Modified Epoxy Resin (a-1-6) A modified epoxy resin containing phenolic hydroxyl groups (a-1-6) was obtained in the same manner as in Production Example 2-2, except that the raw material epoxy resin (vi) was used and the amount of 4-aminophenol added was 5.6 g.

[0126] [Manufacturing Example 2-7] Manufacturing of Modified Epoxy Resin (a-1-7) A modified epoxy resin containing phenolic hydroxyl groups (a-1-7) was obtained in the same manner as in Production Example 2-2, except that the raw material epoxy resin (vi) was used and the amount of 4-aminophenol added was 9.2 g.

[0127] [Manufacturing Example 2-8] Manufacturing of Modified Epoxy Resin (a-1-8) A modified epoxy resin containing hydroxyl groups (a-1-8) was obtained in the same manner as in Production Example 2-3, except that the raw material epoxy resin (vi) was used and the amount of diethanolamine added was 1.1 g.

[0128] [Manufacturing Example 2-9] Manufacturing of Modified Epoxy Resin (a-1-9) A modified epoxy resin containing hydroxyl groups (a-1-9) was obtained in the same manner as in Production Example 2-3, except that the raw material epoxy resin (vi) was used and the amount of diethanolamine added was 2.7 g.

[0129] [Manufacturing Example 2-10] Manufacturing of Modified Epoxy Resin (a-1-10) A modified epoxy resin containing hydroxyl groups (a-1-10) was obtained in the same manner as in Production Example 2-3, except that the raw material epoxy resin (vi) was used and the amount of diethanolamine added was 4.3 g.

[0130] [Manufacturing Example 2-11] Manufacturing of Modified Epoxy Resin (a-1-11) A modified epoxy resin containing hydroxyl groups (a-1-11) was obtained in the same manner as in Production Example 2-3, except that the raw material epoxy resin (vi) was used and the amount of diethanolamine added was 11.2 g.

[0131] [Manufacturing Example 2-12] Manufacturing of Modified Epoxy Resin (a-1-12) A modified epoxy resin containing hydroxyl groups (a-1-12) was obtained in the same manner as in Production Example 2-3, except that the raw material epoxy resin (vi) was used and the amount of diethanolamine added was 14.1 g.

[0132] [Manufacturing Example 2-13] Manufacturing of Modified Epoxy Resin (a-1-13) A carboxyl group-containing modified epoxy resin (a-1-13) was obtained in the same manner as in Production Example 2-1, except that the raw material epoxy resin (vi) was used and the amount of adipic acid added was 3.0 g.

[0133] [Manufacturing Example 2-14] Manufacturing of Modified Epoxy Resin (a-1-14) A carboxyl group-containing modified epoxy resin (a-1-14) was obtained in the same manner as in Production Example 2-1, except that the raw material epoxy resin (vi) was used and the amount of adipic acid added was 7.3 g.

[0134] [Manufacturing Example 2-15] Manufacturing of Modified Epoxy Resin (a-1-15) A carboxyl group-containing modified epoxy resin (a-1-15) was obtained in the same manner as in Production Example 2-1, except that the raw material epoxy resin (vi) was used and the amount of adipic acid added was 11.8 g.

[0135] [Manufacturing Example 2-16] Manufacturing of Modified Epoxy Resin (a-1-16) A modified epoxy resin containing a carboxyl group (a-1-16) was obtained in the same manner as in Production Example 2-1, except that the raw material epoxy resin (vi) was used and the amount of adipic acid added was 23.4 g.

[0136] [Manufacturing Example 2-17] Manufacturing of Modified Epoxy Resin (a-1-17) A modified epoxy resin containing phenolic hydroxyl groups (a-1-17) was obtained in the same manner as in Production Example 2-2, except that raw material epoxy resin (ii) was used and the amount of 4-aminophenol added was 7.4 g.

[0137] [Manufacturing Example 2-18] Manufacturing of Modified Epoxy Resin (a-1-18) A modified epoxy resin containing hydroxyl groups (a-1-18) was obtained in the same manner as in Production Example 2-3, except that raw material epoxy resin (ii) was used and the amount of diethanolamine added was 4.3 g.

[0138] [Modified novolac epoxy resin (a-1-19)] Product name "HARIPOL EP497", manufactured by Harima Chemicals, Inc., weight-average molecular weight 7900, solids content 60% by mass, epoxy equivalent 750 g / eq, chain extender with dimer acid, and contains 0.09 mol / kg of phenolic hydroxyl groups.

[0139] [Manufacturing Example 3-1] Manufacturing of other epoxy resins (a-3-1) 200g of the raw epoxy resin (iv) obtained above was charged into a 2L reactor, 4.4g of diethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was aged at 100°C for 2 hours. This yielded the other epoxy resin (a-3-1).

[0140] [Manufacturing Example 3-2] Manufacturing of other epoxy resins (a-3-2) 200g of the raw epoxy resin (iii) obtained above was placed in a 2L reactor, 4.4g of diethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was aged at 100°C for 2 hours. This yielded the other epoxy resin (a-3-2).

[0141] Table 1 summarizes the physical properties of the epoxy resins mentioned above.

[0142] [Table 1]

[0143] [Examples 1-45, Comparative Examples 1-18] The main component and hardener were prepared according to the formulations shown in Tables 2-11. The main component and hardener were mixed to prepare the anticorrosive coating composition. Tables 2-11 show the proportions of each component on a solids basis.

[0144] The details of each component shown in Tables 2-11 are as follows: Polyamine (b) • Alicyclic polyamine (b-1): 1,3-bis(aminomethyl)cyclohexane, manufactured by Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent 34.2 g / eq, weight-average molecular weight 142.24 • Non-alicyclic polyamine (b-2): m-xylylenediamine, manufactured by Tokyo Chemical Industry Co., Ltd., active hydrogen equivalent 35.5 g / eq, weight-average molecular weight 136.19

[0145] Alkylphenol ·o-tert-butylphenol Thickening agent • Product name: F-9050, manufactured by Kusumoto Kasei Co., Ltd. defoaming agent • Product name: Disparon 1958, manufactured by Kusumoto Kasei Co., Ltd. Weak solvent • Solvesso 100, manufactured by Esso Petroleum Company

[0146] [evaluation] The anticorrosion coating compositions were evaluated using the following method. The evaluation results are shown in Tables 2 to 11.

[0147] (1) Coating film resistance value A corrosion-preventive coating composition was spray-applied to an SS400 grid-blasted steel plate, and dried at 23°C for one week to produce a coated plate with a 60 μm thick primer film. The resulting coated plate was then immersed in deionized water in a 35°C constant temperature bath for 24 hours.

[0148] Subsequently, the painted plate 4 was assembled using the resistance measuring device 10 shown in Figure 1, in the same manner as described above. Next, as shown in Figure 2, a voltage of ±0.5 (V) was applied between the electrodes, and the resistance value was calculated in the same manner as described above. The obtained resistance value was multiplied by the evaluation area to obtain the coating resistance value (Ω·cm). 2 The wet coating resistance value was obtained. The volume resistivity (Ω·cm) was obtained by dividing the obtained wet coating resistance value by the coating thickness of the test piece.

[0149] (2) Interval adhesion Apply the anticorrosive coating composition using a brush at a rate of 200 g / m². 2 The paint was applied to SS400 grid-blasted steel plates and dried at 23°C for 7 days. After that, the painted plates were exposed to a daily solar radiation of 20 MJ / m². 2The boards were then left outdoors for a period equivalent to 10 days of cumulative solar radiation. Next, 140 g / m² of Nippon Paint's "Hypon 30 Fine Intermediate Coat" (containing epoxy resin and polyamine) was applied to the aforementioned coated boards using a brush. 2 The test panels were painted and dried at 23°C for 7 days to obtain the test plates.

[0150] The test panels were left undisturbed for 7 days in a humidity resistance test chamber at 50°C and 100% RH. After removing the test panels, the cross-cut method was immediately performed in accordance with JIS K5600-5-6, with a gap spacing of 2 mm and 25 grid squares. The apparent number of peeled grid squares was calculated by dividing the total peeled area of ​​the coating by the area of ​​one grid square, and this number of peeled grid squares was evaluated according to the following criteria.

[0151] (Evaluation Criteria) 5:25 Mass separation 4:15~25 sections peeled off 3:5~15 squares peeled off 2:2~5 squares peeling 1:0~2 squares peeling 0: No peeling

[0152] Except for replacing "Hypon 30 Fine Intermediate Coat" with "Hypon 20 Fine" (containing epoxy resin and polyamine), "Hypon 30 Fine Intermediate Coat U" (containing polyol and isocyanate), "Hypon 50 Fine HB" (containing polyol and polyisocyanate), "Hypon 50 Fine" (containing polyol and polyisocyanate), "Hypon Double Guard U" (containing polyol and polyisocyanate), and "Hypon Double Guard Si" (containing polyol and polyisocyanate) (all manufactured by Nippon Paint Co., Ltd.), test panels were prepared, tested, and evaluated in the same manner as above.

[0153] (3) Impact resistance A corrosion-preventive coating composition was spray-applied to an SS400 grid-blasted steel plate, and dried at 23°C for one week to produce a coated plate with a primer film. The obtained painted boards were subjected to a weight-drop resistance test in accordance with JIS K 5600-5-3. The appearance of the coating after the test was visually evaluated according to the following criteria.

[0154] (Evaluation Criteria) A. No cracks or fissures are visible. B. Cracks and fissures can be observed.

[0155] (4) Practicality The wet coating resistance value is 1.0 × 10 9 Ω·cm 2 In summary, if the interval adhesion performance was rated 0-2 and the impact resistance was rated A, it was considered suitable for practical use and given a rating of A. All other cases were rated B.

[0156] [Table 2]

[0157] [Table 3]

[0158] [Table 4]

[0159] [Table 5]

[0160] [Table 6]

[0161] [Table 7]

[0162] [Table 8]

[0163] [Table 9]

[0164] [Table 10]

[0165] [Table 11]

[0166] The present invention encompasses the following embodiments. [1] It contains a main component (I) and a hardening agent (II), The main component (I) comprises epoxy resin (a), The epoxy resin (a) is A modified novolac-type epoxy resin (a-1) having at least one functional group selected from the group consisting of hydroxyl groups, phenolic hydroxyl groups, and carboxyl groups at a concentration of 0.06 mol / kg or more, and having a weight-average molecular weight of 3000 to 12000, The present invention comprises a novolac-type epoxy resin (a-2) which either does not have the aforementioned functional group or has less than 0.06 mol / kg of it, and has a weight-average molecular weight of 5000 or more and 12000 or less, The curing agent (II) contains polyamine (b) and 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. The solid content of the alicyclic polyamine (b-1) is 30% by mass or more and 90% by mass or less of the solid content of the curing agent (II). The solid 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 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). A corrosion-preventive coating composition wherein the solid content of the modified novolac-type epoxy resin (a-1) is 5 parts by mass or more and 70 parts by mass or less, based on 100 parts by mass of the total solid content of the epoxy resin (a). [2] The anticorrosive coating composition according to [1] above, wherein the ratio 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) (amount of active hydrogen groups / amount of epoxy groups) is 0.8 or more and 1.2 or less. [3] The modified novolac-type epoxy resin (a-1) is the anticorrosive coating composition according to [1] or [2] above, wherein the novolac-type epoxy resin is chain-extended by a chain-like aliphatic group-containing dicarboxylic acid. [4] The coating film with a thickness of 60 μm formed by the aforementioned anticorrosive coating composition has a coating film resistance value of 1.0 × 10⁻¹⁰ after being immersed in ion-exchanged water at 35°C for 24 hours. 9 Ω·cm 2 The above-mentioned anticorrosive coating composition is one of the above [1] to [3]. [5] The non-alicyclic polyamine (b-2) comprises at least one selected from the group consisting of a linear aliphatic polyamine, a polyamine having an aromatic hydrocarbon group, and a polyamine having a heterocycle, in any of the above [1] to [4] anticorrosion coating compositions. [6] Furthermore, a corrosion-preventive coating composition containing any of the above [1] to [5], comprising a weak solvent (e). [7] Furthermore, it contains pigment (f), The anticorrosion coating composition is any of the above [1] to [6], wherein the pigment volume concentration in the anticorrosion coating composition is 25% by volume or more and 50% by volume or less. [8] A metal object to be coated, A painted article comprising: a primer coating film formed on the object to be coated with any of the anticorrosive paint compositions [1] to [7] above; and [9] The painted article according to [8] further comprises another coating film adjacent to the primer coating film, formed by a coating composition comprising at least one selected from the group consisting of polyols, polyisocyanates, epoxy resins, and polyamines. [Industrial applicability]

[0167] The present invention provides a corrosion-resistant coating composition that provides excellent corrosion resistance and excellent adhesion to other coatings even when there are long intervals between multiple coating processes. The corrosion-resistant coating composition is particularly suitable for priming steel materials used in large structures such as plants, bridges, transmission towers, and buildings. [Explanation of Symbols]

[0168] 10 Resistance measuring device 1 Temperature bath 2. Deionized water 3 Platinum electrode 4 Painted boards 5 High resistance measuring device 6. Temperature sensor 7 Thermometer

Claims

1. It contains a main component (I) and a hardening agent (II), The main component (I) comprises epoxy resin (a), The epoxy resin (a) is A modified novolac-type epoxy resin (a-1) having 0.06 mol / kg or more of at least one functional group selected from the group consisting of hydroxyl groups, phenolic hydroxyl groups, and carboxyl groups, and having a weight-average molecular weight of 3000 to 12000, The present invention comprises a novolac-type epoxy resin (a-2) which either does not have the aforementioned functional group or has less than 0.06 mol / kg of it, and has a weight-average molecular weight of 5000 or more and 12000 or less, The curing agent (II) comprises 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. The solid content of the alicyclic polyamine (b-1) is 30% by mass or more and 90% by mass or less of the solid content of the curing agent (II). The solid 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 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). A corrosion-preventive coating composition wherein the solid content of the modified novolac-type epoxy resin (a-1) is 5 parts by mass or more and 70 parts by mass or less, based on 100 parts by mass of the total solid content of the epoxy resin (a).

2. The corrosion-preventive coating composition according to claim 1, wherein the ratio 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) (amount of active hydrogen groups / amount of epoxy groups) is 0.8 or more and 1.2 or less.

3. The anticorrosion coating composition according to claim 1 or 2, wherein the modified novolac-type epoxy resin (a-1) is a novolac-type epoxy resin whose chain is extended by a chain-like aliphatic group-containing dicarboxylic acid.

4. The coating film with a thickness of 60 μm formed by the aforementioned anticorrosive coating composition has a coating film resistance value of 1.0 × 10⁻¹⁰ after being immersed in ion-exchanged water at 35°C for 24 hours. ９ Ω・cm ２ The anticorrosion coating composition according to claim 1 or 2.

5. The anticorrosion 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 a linear aliphatic polyamine, a polyamine having an aromatic hydrocarbon group, and a polyamine having a heterocycle.

6. Furthermore, the anticorrosive coating composition according to claim 1 or 2, comprising a weak solvent (e).

7. Furthermore, it contains pigment (f), The anticorrosion coating composition according to claim 1 or 2, wherein the volume concentration of the pigment in the anticorrosion coating composition is 25% by volume or more and 50% by volume or less.

8. A metal object to be coated, A painted article comprising a primer coating film formed on the object to be coated with the anticorrosive paint composition according to claim 1 or 2.

9. The painted article according to claim 8, further comprising another coating film formed adjacent to the primer coating film by a coating composition comprising at least one selected from the group consisting of polyols, polyisocyanates, epoxy resins, and polyamines.

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