Anticorrosive coating composition and method for anticorrosive coating on wet surfaces

Abstract

To provide an anticorrosive coating composition that can be readily applied even when a substrate is in a wet state, and can form a coated film excellent in corrosion control.SOLUTION: An anticorrosive coating composition for wet surfaces contains an epoxy resin (A), a pigment (B), a polyamine compound (C), and an organic solvent (D), in which a nonvolatile component is in the range of 60 to 99 mass%, an active hydrogen equivalent ratio of the polyamine compound (C) to 1 equivalent amount of epoxy group of the epoxy resin is in the range of 0.4 to 3.0, and the organic solvent (D) contains 40 mass% or larger of an organic solvent (D1) defined in the third category of industrial safety and health law, and does not include any one organic solvent (D2) defined in the second type organic solvent of the industrial safety and health law, or the content is smaller than 5 mass% in the organic solvent (D), and a wet surface anticorrosive coating method.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an anticorrosive coating composition suitable for wet surfaces and an anticorrosive coating method. [Background technology]

[0002] The anticorrosive coatings of so-called marine structures such as oil platforms or oil rigs, piers, and offshore airports, which were constructed during the period of high economic growth, are reaching the time for repair due to deterioration over time. However, since these marine structures cannot be moved from their installation areas, painting work must be carried out in the marine environment. Normally, coatings applied to substrates in the sea are prone to peeling due to strong water currents and water pressure. For this reason, when repair painting is carried out on substrates in the sea, a coating composition with extremely high viscosity is applied by stroking with a trowel or spatula.

[0003] Patent Document 1 discloses a coating composition for use in undersea painting for undersea steel structures, which contains a liquid epoxy resin, a polyamine curing agent, and a solid proton donor.

[0004] Such coating compositions have high viscosity, which provides excellent coating workability underwater and also provides excellent adhesion to substrates after film formation. However, there is a problem in that coating with a spray or brush or coating on substrates having narrow gaps or uneven surfaces is difficult.

[0005] The painted parts of underwater structures are classified into submarine areas, which are always submerged in the sea; tidal areas, which are repeatedly exposed and immersed in seawater due to the ebb and flow of the tides; splash areas, which are always exposed to the atmosphere and are exposed to wave spray; and above-sea atmospheric areas, which are always exposed to the atmosphere and not exposed to wave spray. Anti-corrosion coatings appropriate to each part are applied. Among these, in areas between the undersea area and the atmosphere, such as the tidal area and the splash area, the corrosive environment changes greatly and the area to be painted is wet with seawater, so it is difficult to impart corrosion protection by painting. Patent documents 2 and 3 disclose anticorrosive coating compositions containing epoxy resins, at least one amine curing agent selected from polyoxyalkylene polyamines, Mannich modified amines and ketimines, water and a hydroxyl group-containing modified resin. This anticorrosive coating composition can be sprayed and can form a coating film with good adhesion and corrosion protection even when the substrate is wet with water, such as the tidal area and the splash area.

[0006] However, although the anticorrosive coating compositions described in Patent Documents 2 and 3 have excellent adhesion to substrates because they contain a large amount of water and hydrophilic functional groups, there is room for improvement in coating workability and corrosion prevention. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2-55789 [Patent Document 2] JP 2017-25158 A [Patent Document 3] JP 2017-25159 A Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide an anticorrosive coating composition which can be easily applied to a substrate even when the substrate is in a wet state and which is suitable for forming a coating film having excellent anticorrosive properties. [Means for solving the problem]

[0009] The present inventors have focused on substrates in a water-wet state and conducted extensive research, and as a result have found that a coating composition containing a specific organic solvent can be easily applied to a substrate surface even when water remains on the substrate surface, and can form a coating film having excellent corrosion resistance on the substrate.

[0010] That is, the present invention provides: Item 1 The epoxy resin (A), the pigment (B), the polyamine compound (C) and the organic solvent (D) are included, the non-volatile content is within the range of 60 to 99 mass%, and the active hydrogen equivalent ratio of the polyamine compound (C) to 1 equivalent of the epoxy group of the epoxy resin is within the range of 0.4 to 3.0, The pigment (B) contains, as a part of its components, a flake-like pigment containing talc and glass flakes, The amount of glass flakes used is more than 0 and less than 59.9 parts by mass based on 100 parts by mass of the non-volatile content of the epoxy resin (A), The polyamine compound (C) is incompatible with an equal-volume mixture of water and acetone and has an active hydrogen equivalent of 126 or more and 500 or less; the organic solvent (D) contains 40% by mass or more of an organic solvent (D1) specified as a third class organic solvent in the Industrial Safety and Health Act, and does not contain any organic solvent (D2) specified as a second class organic solvent in the Industrial Safety and Health Act, or, if it contains any one of the organic solvents (D2), the content of any one of the organic solvents (D2) is less than 5.0% by mass in the organic solvent (D); and, if the organic solvent (D2) is a combination of multiple organic solvents, the content of each of the multiple organic solvents (D2) in the organic solvent (D) is less than 5% by mass; The organic solvent (D1) is at least one selected from gasoline, coal tar naphtha, petroleum ether, petroleum naphtha, petroleum benzine, turpentine, mineral spirits, and combinations thereof; An anticorrosion coating composition for wet surfaces, wherein the organic solvent (D2) is at least one selected from acetone, isobutyl alcohol, isopropyl alcohol, isopentyl alcohol, ethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-butyl ether, ethylene glycol monomethyl ether, ortho-dichlorobenzene, xylene, cresol, chlorobenzene, isobutyl acetate, isopropyl acetate, isopentyl acetate, ethyl acetate, n-butyl acetate, n-propyl acetate, n-pentyl acetate, methyl acetate, cyclohexanol, cyclohexanone, N·N-dimethylformamide, tetrahydrofuran, trichloroethane, toluene, n-hexane, 1-butanol, 2-butanol, methanol, methyl ethyl ketone, methylcyclohexanol, methylcyclohexanone, methyl-n-butyl ketone, and combinations thereof (excluding those in which the content of stannous sulfate is 2.0 to 8.0 parts by mass per 100 parts by mass of the coating composition). Section 2 Item 2. The anticorrosive coating composition according to Item 1, wherein the epoxy resin (A) is a modified epoxy resin having a number average molecular weight of 900 or more. Section 3 Item 3. The anticorrosive coating composition according to item 1 or 2, wherein the pigment (B) contains an anticorrosive pigment as a part of its components. Section 4 Further, the present invention includes a silane coupling agent. 3 13. The anticorrosive coating composition according to claim 12 . Section 5 The paint form is a two-component composition comprising a base component containing an epoxy resin (A) and a pigment (B) and a curing agent component containing a polyamine compound (C), and the base component and / or the curing agent component contains an organic solvent (D). 4 13. The anticorrosive coating composition according to claim 12 . Section 6 The paint is a two-component composition comprising a base component containing an epoxy resin (A) and a pigment (B) and a curing agent component containing a polyamine compound (C), the base component and / or the curing agent component containing an organic solvent (D), and the base component and / or the curing agent component containing a silane coupling agent. 4 The anticorrosive coating composition according to claim 1. Section 7 On the wet surface, items 1 to 6 13. A method for anticorrosive coating of a wet surface, comprising coating the anticorrosive coating composition according to claim 12. Regarding. Effect of the Invention

[0011] The anticorrosive coating composition of the present invention can be easily applied using simple coating tools such as a roller or a brush without being affected by water remaining on the substrate surface. Furthermore, the formed coating film has a good appearance and is sufficiently excellent in anticorrosive properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] <Epoxy resin (A)> In the present invention, the epoxy resin (A) is a resin having at least two epoxy groups in the molecule, and has a number average molecular weight of 900 or more, preferably 900 to 10,000, and more preferably 900 to 8,000, and an epoxy group equivalent of 80 to 2,400, and preferably 200 to 1,500.

[0013] In this specification, the number average molecular weight is a value obtained by converting the weight average molecular weight measured by gel permeation chromatography into the weight average molecular weight of polystyrene as a standard.

[0014] Specifically, the weight average molecular weight measured by a gel permeation chromatograph ("HLC8120GPC" manufactured by Tosoh Corporation) can be converted based on the weight average molecular weight of polystyrene. Four columns, "TSKgel G-4000HxL", "TSKgel G-3000HxL", "TSKgel G-2500HxL", and "TSKgel G-2000HxL" (all manufactured by Tosoh Corporation, trade names), were used, and the measurement was performed under the following conditions: mobile phase: tetrahydrofuran, measurement temperature: 40°C, flow rate: 1 cc / min, and detector: RI.

[0015] In this specification, the "epoxy equivalent" refers to the mass (g) of resin (non-volatile content) per 1 gram equivalent of epoxy groups, and can be measured as follows in accordance with JIS K7236 (1995).

[0016] Dissolve the sample in chloroform and acetic acid, add 10 ml of a solution prepared by dissolving 100 g of tetraethylammonium bromide in 400 ml of acetic acid to the solution, titrate with a perchloric acid acetic acid solution using crystal violet as an indicator, and calculate using the following formula. Epoxy equivalent (g / eq) = 1000 x m / (C x V) m: mass of non-volatile matter in the sample (g), C: concentration of perchloric acid / acetic acid in the titrant, V: Titration amount.

[0017] Specific examples of the epoxy resin (A) include epoxy resins such as glycidyl ether type epoxy resins, glycidyl ester type epoxy resins, alicyclic epoxy resins, dimer acid diglycidyl esters, and novolac type epoxy resins; and epoxy group-introduced alkylphenol or alkylphenol novolac type resins obtained by reacting alkylphenol or alkylphenol novolac type resins with other epoxy resins such as glycidyl ether type epoxy resins.

[0018] The glycidyl ether type epoxy resin may be, for example, an epoxy resin having a glycidyl ether group obtained by reacting a polyhydric alcohol, a polyhydric phenol, or the like with an epihalohydrin or an alkylene oxide.

[0019] Examples of the polyhydric alcohol include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, neopentyl glycol, butylene glycol, hexanediol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, diglycerin, and sorbitol.

[0020] Examples of the polyhydric phenol include 2,2-bis(4-hydroxyphenyl)propane [bisphenol A], 2,2-bis(2-hydroxyphenyl)propane, 2-(2-hydroxyphenyl)2-(4-hydroxyphenyl)propane, halogenated bisphenol A, bis(4-hydroxyphenyl)methane [bisphenol F], tris(4-hydroxyphenyl)propane, resorcinol, tetrahydroxyphenylethane, 1,2,3-tris(2,3-epoxypropoxy)propane, novolac-type polyhydric phenols, and cresol-type polyhydric phenols.

[0021] Examples of the other glycidyl type epoxy resins include tetraglycidylaminodiphenylmethane and triglycidyl isocyanurate.

[0022] Examples of the alicyclic epoxy resin include (3,4-epoxy-6-methylcyclohexyl)methyl-3,4-epoxy-6-methylcyclohexane carboxylate, (3,4-epoxycyclohexyl)methyl-3,4-epoxycyclohexane carboxylate, bis(3,4-epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, "Epolead GT300" (manufactured by Daicel Chemical Industries, Ltd., trade name, trifunctional alicyclic epoxy resin), "Epolead GT400" (manufactured by Daicel Chemical Industries, Ltd., trade name, tetrafunctional alicyclic epoxy resin), and "EHPE" (manufactured by Daicel Chemical Industries, Ltd., trade name, multifunctional alicyclic epoxy resin).

[0023] In the present invention, it is preferable that the epoxy resin (A) is a modified resin modified with an alkylphenol and / or a fatty acid from the viewpoint of coating workability on wet surfaces.

[0024] The alkylphenol is preferably a phenol having an alkyl group having about 2 to 18 carbon atoms, and specific examples include para-t-butylphenol, para-octylphenol, nonylphenol, and novolak resins obtained by condensing these with aldehydes.

[0025] The fatty acid includes aliphatic monocarboxylic acids having 6 to 24 carbon atoms, particularly 12 to 20 carbon atoms, and can be used with no particular limitation as known unsaturated or saturated fatty acids, such as fish oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid, linseed oil fatty acid, soybean oil fatty acid, sesame oil fatty acid, poppy oil fatty acid, eno oil fatty acid, hemp seed oil fatty acid, grape kernel oil fatty acid, corn oil fatty acid, tall oil fatty acid, sunflower oil fatty acid, cottonseed oil fatty acid, walnut oil fatty acid, rubber seed oil fatty acid, etc.; non-drying oil fatty acid such as coconut oil fatty acid, hydrogenated coconut oil fatty acid, palm oil fatty acid, etc.; and saturated fatty acids such as caproic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, etc. Among these, from the viewpoint of room temperature crosslinking, drying oil fatty acid and semi-drying oil fatty acid are suitable.

[0026] In the present invention, the epoxy resin (A) may be a commercially available product, or may be prepared by synthesis.

[0027] <Pigment (B)> In the present invention, the pigment (B) may be any color pigment, extender pigment or rust-preventive pigment known in the paint field.

[0028] Specific examples of color pigments include white pigments such as titanium dioxide; black pigments such as carbon black, acetylene black, lamp black, carbon black, graphite, iron black, and aniline black; yellow pigments such as yellow iron oxide, titanium yellow, monoazo yellow, condensed azo yellow, azomethine yellow, bismuth vanadate, benzimidazolone, isoindolinone, isoindoline, quinophthalone, benzidine yellow, and permanent yellow; orange pigments such as permanent orange; red pigments such as red iron oxide, naphthol AS azo red, anthanthrone, anthraquinonyl red, perylene maroon, quinacridone red pigments, diketopyrrolopyrrole, watching red, and permanent red; purple pigments such as cobalt purple, quinacridone violet, and dioxazine violet; blue pigments such as cobalt blue, phthalocyanine blue, and threne blue; and green pigments such as phthalocyanine green. These can be used alone or in combination of two or more.

[0029] The content of the color pigment can be adjusted depending on the type of color pigment used, but is generally within the range of 5 to 80 parts by mass, particularly 10 to 70 parts by mass, based on 100 parts by mass of the nonvolatile content of the epoxy resin (A).

[0030] In this specification, the non-volatile content means the residue after removing the volatile components, and the residue may be in a solid or liquid form at room temperature. The mass of the non-volatile content can be calculated by multiplying the non-volatile content rate, which is the ratio of the amount of the remaining substance when dried to the mass before drying, by the mass of the sample before drying. The conditions for determining the non-volatile content rate are a sample mass of about 1 gram and drying conditions of 110°C and 3 hours.

[0031] Examples of the extender pigment include calcium carbonate, barium sulfate, talc, magnesium carbonate, calcium sulfate, diatomaceous earth, mica, clay, kaolin, silica, alumina, aluminum, baryte powder, bentonite, lithopone, glass flakes, glass fiber, carbon fiber, mineral fiber, molybdenum disulfide, wollastonite, montmorillonite, beidellite, hectorite, saponite, stevensite, sericite, illite, vermiculite, etc. These can be used alone or in combination of two or more kinds.

[0032] The content of the extender pigment is suitably within the range of 5 to 300 parts by mass, preferably 10 to 250 parts by mass, based on 100 parts by mass of the nonvolatile content of the epoxy resin (A).

[0033] In the present invention, from the viewpoint of corrosion prevention against a substrate on a wet surface, it is suitable to use a scaly pigment as a part of the pigment (B). In this specification, scaly is not limited to a scale shape but includes shapes such as a plate shape, and refers to a thin flake shape obtained by crushing a three-dimensional shape such as a sphere or a lump in one direction.

[0034] Specific examples of such scaly pigments include talc, mica, scaly alumina, scaly silica, leaf-shaped silica, scaly molybdenum disulfide, glass flakes, scaly aluminum, montmorillonite, beidellite, hectorite, saponite, stevensite, sericite, illite, kaolin, vermiculite, clay, and the like. These may be used alone or in combination of two or more.

[0035] In the present invention, it is preferable to use talc and / or glass flakes as the scaly pigment. In this case, the amount of talc used is within a range of 10 to 160 parts by mass, or 20 to 150 parts by mass, based on the non-volatile content of the epoxy resin (A), and the amount of glass flakes used is within a range of 5 to 80 parts by mass, or 10 to 70 parts by mass.

[0036] As the rust-preventive pigment, those known in the field of paints can be used. Specific examples thereof include phosphate-based metal compounds such as zinc phosphate, magnesium phosphate, magnesium phosphate-ammonium co-deposit, magnesium monohydrogen phosphate, magnesium dihydrogen phosphate, magnesium phosphate-calcium co-deposit, magnesium phosphate-cobalt co-deposit, magnesium phosphate-nickel co-deposit, calcium phosphate, calcium ammonium phosphate, calcium monohydrogen phosphate, calcium dihydrogen phosphate, calcium fluoride phosphate, aluminum phosphate, and aluminum hydrogen phosphate; phosphite-based metal compounds such as magnesium phosphite, calcium phosphite, magnesium phosphite-calcium co-deposit, basic zinc phosphite, barium phosphite, manganese phosphite, and calcium hypophosphite; calcium silicate, zinc silicate, aluminum silicate, aluminum orthosilicate, hydrated aluminum silicate, aluminosilicate, borosilicate, beryllosilicate, and calcium aluminum silicate. Examples of the metal silicates include calcium, sodium aluminum silicate, beryllium aluminum silicate, sodium silicate, calcium orthosilicate, calcium metasilicate, sodium calcium silicate, zirconium silicate, magnesium orthosilicate, magnesium metasilicate, magnesium-calcium silicate, manganese silicate, and barium silicate; metal ion-exchanged silica compounds such as magnesium ion-exchanged silica and calcium ion-exchanged silica; tripolyphosphate metal compounds such as aluminum dihydrogen tripolyphosphate, magnesium tripolyphosphate, aluminum tripolyphosphate, and zinc dihydrogen tripolyphosphate; molybdate metal compounds such as aluminum molybdate, calcium molybdate, and aluminum phosphomolybdate; composite oxides of iron oxide and magnesium oxide, composite oxides of iron oxide and calcium oxide; zinc oxide, and zinc compounds of iron oxide and zinc oxide. As mentioned above, these may be used alone or in combination of two or more, or may be composites of two or more. In addition, the rust-preventive pigment also includes modified or treated compounds of these exemplary compounds with silica, calcium silicate, and other silicic acid compounds, magnesium oxide, and other magnesium oxide compounds.

[0037] The rust-preventive pigment may be a commercially available product, either alone or in combination. Examples of such commercially available products include "EXPERT NP-1000", "EXPERT NP-1020C", "EXPERT NP-1100", and "EXPERT NP-1102" (all of which are product names manufactured by Toho Pigment Co., Ltd.), "LF BOSEI CP-Z", "LF BOSEI MZP-500", "LF BOSEI CRFC-1", "LF BOSEI M-PSN", "LF BOSEI MC-400WR", "LF BOSEI PM-300", and "LF BOSEI PM-308" (all of which are product names manufactured by Kikuchi Color Co., Ltd.), "K-WHITE140", "K-WHITE Ca650", "K-WHITE450H", "K-WHITE G-105", "K-WHITE #105", "K-WHITE #82", and "K-WHITE G102S" (all of which are product names manufactured by Teika Co., Ltd.), "SHIELDEX C303", "SHIELDEX Examples of such masks include "AC-3", "SHIELDEXC-5" (all manufactured by W.R. Grace & Co.), "Silomask 52", "Silomask 52M", "Silomask 22MR-H" (manufactured by Fuji Silysia), and "Novinox ACE-110" (manufactured by SNCZ, France).

[0038] When the anti-rust pigment is used, the amount is suitably within the range of 1 to 50 parts by mass, or 5 to 50 parts by mass, based on 100 parts by mass of the non-volatile content of the epoxy resin (A).

[0039] <Polyamine Compound (C)> In the present invention, the polyamine compound (C) is a compound having at least two amino groups in the molecule. Specific examples include aliphatic polyamines, aromatic polyamines, aliphatic polyamidoamines, aromatic polyamidoamines, and amine resins which are epoxy adduct modified products obtained by reacting these polyamines or polyamidoamines with epoxy resins.

[0040] Examples of the aliphatic polyamines include ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, pentaethylenehexamine, and modified polyamines thereof, and examples of the aromatic polyamines include phenylenediamine, xylylenediamine, and modified polyamines thereof, etc. Examples of the polyamidoamines include products such as polyamidoamine obtained by reacting the aliphatic or aromatic polyamines with dimer acid (polymerization product of unsaturated fatty acid) or other polycarboxylic acids, and modified polyamidoamines thereof.

[0041] In the present invention, the polyamine compound (C) may be a commercially available product, or may be prepared by synthesis.

[0042] The polyamine compound (C) preferably has an active hydrogen equivalent in the range of 25 to 2000, preferably 50 to 500, and more preferably 70 to 200, from the viewpoints of coating workability on wet surfaces and corrosion resistance of the coating film.

[0043] In the present invention, it is preferable that the polyamine compound (C) is incompatible with a mixture of equal parts of water and acetone. By using the polyamine compound (C) having such characteristics, the anticorrosive coating composition of the present invention has excellent coating workability on wet surfaces, and the coating film formed on the wet surfaces has excellent corrosion resistance.

[0044] In this specification, the compatibility of the polyamine compound (C) with a mixture of equal amounts of water and acetone is determined as follows.

[0045] In a 250 ml round can, 50 g of deionized water and 50 g of acetone as a compatibilizer are placed, and polyamine compound (C) is added so that the non-volatile content is 50 g. While maintaining the temperature of the liquid in the round can at 20°C, the liquid is stirred and mixed with a disperser at 900 rpm for 30 minutes to prepare a suspension. 25 g of the obtained suspension is placed in a transparent container with a capacity of 50 ml, and the temperature of the liquid in the transparent container is adjusted to 20°C. After centrifugal separation is performed for 30 minutes under the condition of a centrifugal acceleration (G) of 3000 calculated by the following formula, the treated liquid is visually observed at a distance of 30 cm. If no layer separation is visible at this time, it is considered to be compatible, and if at least one layer separation is visible, it is considered to be incompatible.

[0046] Centrifugal acceleration (G) = {r × (2πN / 60) 2} / g (In the formula, N is the number of rotations per minute (rpm), r is the radius of rotation (m), and g is the gravitational acceleration (9.8 m / s 2 ), and π refers to pi.

[0047] Here, layer separation means that as the water-acetone-polyamine suspension shrinks due to coalescence of water droplets and sedimentation caused by the difference in specific gravity with the polyamine, the polyamine-containing polyphilic layer and the hydrophilic layer containing water each gradually increase in size, and the suspension separates into two layers, an upper and lower layer consisting of a polyamine-containing layer and a hydrophilic layer, or two layers consisting of a hydrophilic layer and a polyamine-containing layer, or into three or more layers consisting of a polyamine-containing layer, at least one intermediate layer, and a hydrophilic layer.

[0048] In the present invention, the amount of the polyamine compound (C) used is such that the ratio of the active hydrogen equivalent of the polyamine compound (C) to 1 equivalent of the epoxy group of the epoxy resin (A) is within the range of 0.4 to 3.0, and more preferably within the range of 0.7 to 2.2. The amount of the polyamine compound (C) relative to the epoxy resin (A) within the above range is helpful in improving the pot life (working time), corrosion prevention properties on wet surfaces, and yellowing resistance of the anticorrosive coating composition of the present invention.

[0049] <Organic solvent (D)> The anticorrosive coating composition of the present invention is an organic solvent-based coating composition containing an organic solvent (D), and the organic solvent (D) is characterized in that it contains an organic solvent (D1) specified as type 3 in the Industrial Safety and Health Act.

[0050] Organic Solvent (D1) In the present invention, the presence of the organic solvent (D1) in the coating composition during coating facilitates coating on wet surfaces. Although the reason for the effect of the organic solvent (D1) is unclear, the inventors believe that the wet coating film adhered to the substrate during coating effectively pushes away water droplets remaining on the substrate surface.

[0051] Specific examples of the organic solvent (D1) include organic solvents specified as the third type in the Industrial Safety and Health Act. More specifically, organic solvents other than the first type organic solvents and the second type organic solvents among the organic solvents specified in Appendix 6-2 of the Ordinance for Prevention of Organic Solvent Poisoning. Organic solvents specified as the third type in the Industrial Safety and Health Act have hydrophobic properties, and therefore have the effect of removing water remaining on the substrate surface. Specific examples include gasoline, coal tar naphtha (also known as solvent naphtha), petroleum ether, petroleum naphtha, petroleum benzine, turpentine, mineral spirits (also known as mineral thinner, petroleum spirits, white spirits, and mineral turpentine), and combinations thereof.

[0052] In the present invention, the content of the organic solvent (D1) is 40% by mass or more, preferably 70% by mass or more, in the organic solvent (D). The content of the organic solvent (D1) within this range is effective in improving the workability of coating with a roller or brush on a wet surface and the corrosion resistance of the coating film formed on the wet surface.

[0053] In the present invention, the organic solvent (D) contains the organic solvent (D1) as an essential component, and the entire amount of the organic solvent (D) may be the organic solvent (D1), but it may also contain other organic solvents. Examples of the other organic solvents include the organic solvent (D2) specified as a type 2 organic solvent in the Industrial Safety and Health Act.

[0054] Organic Solvent (D2) As an organic solvent (D2), it is a type 2 organic solvent specified in the Industrial Safety and Health Act, and more specifically, it is a type 2 organic solvent among the organic solvents specified in Appendix 6-2 of the Ordinance for Prevention of Organic Solvent Poisoning. Specific examples include acetone, isobutyl alcohol, isopropyl alcohol, isopentyl alcohol (also known as isoamyl alcohol), ethyl ether, ethylene glycol monoethyl ether (also known as cellosolve), ethylene glycol monoethyl ether acetate (also known as cellosolve acetate), ethylene glycol mono-normal-butyl ether (also known as butyl cellosolve), ethylene glycol monomethyl ether (also known as methyl cellosolve), ortho-dichlorobenzene, xylene, cresol, chlorobenzene, isobutyl acetate, and acetic acid. Isopropyl, isopentyl acetate (also known as isoamyl acetate), ethyl acetate, n-butyl acetate, n-propyl acetate, n-pentyl acetate (also known as n-amyl acetate), methyl acetate, cyclohexanol, cyclohexanone, N·N-dimethylformamide, tetrahydrofuran, trichloroethane, toluene, n-hexane, 1-butanol, 2-butanol, methanol, methyl ethyl ketone, methyl cyclohexanol, methyl cyclohexanone, methyl n-butyl ketone, and combinations thereof.

[0055] In the present invention, the organic solvent (D) may not contain any organic solvent (D2) at all, or, when the organic solvent (D) contains organic solvent (D2), the content of any one of the organic solvents (D2) in the organic solvent (D) may be less than 5 mass%. In the present invention, when the organic solvent (D2) is a combination of two or more of the above-mentioned exemplified organic solvents, the total content of the two or more organic solvents in organic solvent (D) may be 5 mass% or more, provided that the content of organic solvent (D1) is within the range of the present invention and the content of each of the two or more organic solvents in organic solvent (D2) is less than 5 mass% in organic solvent (D).

[0056] In the present invention, the organic solvent (D) may also include other organic solvents other than the organic solvent (D1) and the organic solvent (D2). The other organic solvents are not particularly limited, but may include, for example, ether-based solvents such as ethylene glycol monoisopropyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, and dioxane; ester-based solvents such as methyl acetoacetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and butyl carbitol acetate; ketone-based solvents such as acetylacetone, diacetone alcohol, methyl isobutyl ketone, and diisobutyl ketone; alcohol-based solvents such as ethanol, n-propanol, isopropanol, isobutanol, n-pentanol, and 1-methoxy-2-propanol; and combinations thereof.

[0057] The organic solvent (D) may be a commercially available product. Examples of commercially available products include "Swasol 1000", "Swasol 1500", and "Swasol 1800" (all trade names, manufactured by Maruzen Oil Co., Ltd.), "Mineral Spirits A", and "T-SOL TM 100 FLUID, T-SOL TM 150 FLUID (all trade names, manufactured by JXTG Nippon Oil & Energy Corporation), "IPZOL 100", "IPZOL 150", and "IPZOL TP" (all trade names, manufactured by Idemitsu Kosan Co., Ltd.) are examples of such fuel oils.

[0058] <Silane coupling agent> The silane coupling agent, which is blended as necessary in the anticorrosive coating composition of the present invention, is a component that can contribute to improving the anticorrosive properties of the coating film that is formed. Examples of the silane coupling agent include N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, N-β(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, methyltrimethoxysilane, vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride, and trimethylchlorosilane. Among them, epoxy group-containing silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, etc. are suitable. When the silane coupling agent is contained, the content is suitably within the range of 0.1 to 10 parts by mass, particularly 0.5 to 5 parts by mass, based on 100 parts by mass of the nonvolatile content of the epoxy resin (A).

[0059] <Anti-corrosion coating composition> The anticorrosive coating composition for wet surfaces of the present invention is a composition comprising an epoxy resin (A), a pigment (B), a polyamine compound (C) and an organic solvent (D).

[0060] The anticorrosive coating composition may contain, as necessary, modifying resins such as alkyd resins and urethane resins; and conventional coating additives such as plasticizers, film-forming assistants, dispersants, surface conditioners, defoamers, preservatives, and thickeners.

[0061] The non-volatile content of the coating composition is in the range of 60 to 99% by mass, preferably in the range of 65 to 85% by mass, because a coating film having excellent workability and excellent corrosion resistance even on wet surfaces can be easily formed by having a non-volatile content in this range.

[0062] The paint form during storage can be appropriately changed depending on the materials used, but it is preferable that the paint is a two-component composition consisting of a base component containing an epoxy resin (A) and a pigment (B) and a curing agent component containing a polyamine compound (C), with the base component and / or the curing agent component containing an organic solvent (D); or, when a silane coupling agent is included, a two-component composition consisting of a base component containing an epoxy resin (A) and a pigment (B) and a curing agent component containing a polyamine compound (C), with the base component and / or the curing agent component containing an organic solvent (D), and the base component and / or the curing agent component containing a silane coupling agent.

[0063] <Corrosion prevention coating method> The anticorrosive coating composition of the present invention is applied to a wet surface. In this specification, the term "wet surface" means that the substrate is in a wet state. The substrate is not particularly limited, but may be steel or non-ferrous metal, and may have a previous coating film. The wet state refers to a state in which water droplets, a water film, or moisture are attached to the substrate surface.

[0064] Specific examples of substrates include the tidal and splash areas of marine steel structures such as offshore oil and gas facilities, piers, offshore airports, ships, and tankers. Wet surfaces also include onshore steel structures such as towers, tanks, and plants with rainwater on them, before they dry after being sprayed with water after surface preparation, or when they are in a high humidity environment and have condensation on them.

[0065] The anticorrosive coating composition is applied to the wet surface so that the dry film thickness is usually within the range of 10 to 2000 μm, preferably 15 to 500 μm per application. The application can be carried out by a known application method, such as air spray, airless spray, brush coating, roller coating, etc. The coating can be dried at room temperature, but forced drying or heat drying may be carried out as necessary.

[0066] In the anticorrosive coating method using the anticorrosive coating composition of the present invention, after the anticorrosive coating composition of the present invention is applied to a wet surface to form a coating film, a known intermediate coating and / or top coating may be applied as necessary. Examples of intermediate coatings include epoxy resin-based intermediate coatings, modified epoxy resin-based intermediate coatings, and urethane resin-based undercoat coatings. Examples of top coatings include acrylic resin-based top coatings, urethane resin-based top coatings, silicone resin-based top coatings, and fluororesin-based top coatings. EXAMPLES

[0067] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0068] <Production of Anticorrosive Coating Composition> Example 1 In a container, 167 parts of 60% modified epoxy resin solution (Note 1), 2.4 parts of γ-glycidoxypropyltrimethoxysilane, 55 parts of titanium white, 15 parts of rust-preventive pigment (Note 3), 100 parts of talc, 40 parts of glass flakes (Note 4), 1 part of defoamer, 2 parts of anti-settling agent, 4 parts of thickener, and 5 parts of mineral spirits were mixed and stirred to obtain the main component. In a separate container, 36 parts of a 70% polyamine solution (note 5) and 45 parts of a hydrocarbon solvent (note 8) were mixed and stirred to obtain a hardener component.

[0069] The curing agent component was added to the vessel containing the main component, and the mixture was stirred and mixed until homogenous to produce an anticorrosive coating composition (A-1).

[0070] Examples 2 to 16 and Comparative Examples 1 to 4 Anticorrosive coating compositions (A-2) to (A-20) were produced in the same manner as in Example 1, except that the materials and amounts used were as shown in Tables 1-1 and 1-2 below. The resulting anticorrosive coating compositions were evaluated as follows.

[0071] [Table 1-1]

[0072] [Table 1-2]

[0073] (Note 1) 60% epoxy resin solution: "EPICLON 5900-60" product name, manufactured by DIC Corporation, non-volatile content 60%, alkylphenol novolac modified epoxy resin with number average molecular weight of 1000, epoxy equivalent per non-volatile content 700, organic solvent (D1) content 40%, (Note 2) Bisphenol A type epoxy resin: "jER 828" product name, bisphenol A type epoxy resin, number average molecular weight 370, epoxy equivalent 190, (Note 3) Anti-rust pigment: "KWHITE G-105", product name, manufactured by Teika Co., Ltd., mixture of aluminum dihydrogen tripolyphosphate and zinc oxide, (Note 4) Glass flake "RCF-140", product name, Nippon Glass Co., Ltd., glass flake, average particle size 140 μm, (Note 5) 70% polyamine solution: "Luckamide B-2201-70ES", product name, manufactured by DIC, modified polyamine, non-volatile content 70%, active hydrogen equivalent per non-volatile content 126, contains 30% organic solvent (D1), water-acetone compatibility test shows two-layer separation, (Note 6) Polyamine compound: "Gaskamin 240", trade name, manufactured by Mitsubishi Gas Chemical Company, polyamidoamine, active hydrogen equivalent 103, water-acetone compatibility test showed two-layer separation, (Note 7) Polyamine compound: "Tomide 225E", product name, manufactured by T&K TOKA, polyamide amine, active hydrogen equivalent 115, water-acetone compatibility test results were transparent (no layer separation) (Note 8) Hydrocarbon organic solvent: "T-SOLTM 100 FLUID" product name, manufactured by JXTG Nippon Oil & Energy Corporation, solvent naphtha, aromatic hydrocarbon organic solvent.

[0074] <Evaluation test> (*)Pot life: After mixing the base resin and hardener, the mixture was left at 20°C and the time (H) until the limit viscosity for paint application with a brush was reached was measured. The higher the value in the table, the better the result. (*)Painting workability (non-wet surfaces): Each of the paints of Examples 1 to 16 and Comparative Examples 1 to 4 was applied to a tinplate with a roller and a brush so that the dry film thickness was 150 μm, and the painting workability was evaluated according to the following criteria. "roller" ◎: There were no problems with the painting process. 〇: The roller is a little heavy or a little light, but it can produce a uniform coating surface. △: The paint was prone to dripping or the painted surface was prone to becoming uneven, so painting work required skill. ×: The roller was too heavy or too light, so a uniform coating surface could not be formed. 《Brush》 ◎: There were no problems with the painting work. 〇: The brush is a little heavy or a little light, but a uniform coating surface can be formed. △: The paint was prone to dripping or the painted surface was prone to becoming uneven, so painting work required skill. ×: The brush was too heavy or too light, so a uniform coating surface could not be formed. (*)Painting workability (wet surface): Tap water 30g / m 2 The coating was carried out in the same manner as above, except that the substrate was a tin plate that had been sprayed and uniformly wetted so that the coating was applied in a manner such that the coating was uniformly wetted. The evaluation criteria were as follows: "roller" ◎: The roller can easily apply paint while removing water droplets from the substrate, allowing for a uniform coating surface. 〇: The roller is slightly affected by water droplets on the substrate, but the paint can be applied to the substrate and a uniform coating surface can be formed. △: The roller is affected by water droplets on the substrate, making it difficult to apply paint to the substrate, but a painted surface can be formed. ×: The roller is significantly affected by the water droplets on the substrate, and the paint cannot be applied to the substrate. 《Brush》 ◎: The brush can easily apply paint while removing water droplets from the base material, allowing for a uniform painted surface. 〇: The brush is slightly affected by water droplets on the substrate, but the paint can be applied to the substrate and a uniform coating surface can be formed. △: The brush is affected by water droplets on the substrate, making it difficult to apply paint to the substrate, but a painted surface can be formed. ×: The brush is significantly affected by water droplets on the substrate, and paint cannot be applied to the substrate.

[0075] (*)Corrosion resistance (non-wet surfaces): Each anticorrosive coating composition was air-sprayed onto a 70 x 150 x 3.2 mm sandblasted steel plate to a dry thickness of 150 μm, and then dried at 23° C. for 7 days to prepare a test plate. Each test plate was cut to the base material, and subjected to a cycle test method based on the combined cycle corrosion test (JIS K-56007-9 Cycle D method) for 1200 hours, after which it was evaluated according to the following criteria. ◎: No blister or rust in the general area, and the width of the rust blister from the cut part is less than 3 mm on average. ○: There are 3 or less small blisters or rust in the general area, but the width of the rust blisters from the cut area is less than 3 mm, or there are no blisters or rust in the general area, and the width of the rust blisters from the cut area is 3 mm or more but less than 7 mm, △: There are more than three blisters or rust in the general area, and the width of the rust blisters from the cut area exceeds 3 mm, or there are no blisters or rust in the general area, but the width of the rust blisters from the cut area exceeds 7 mm. ×: Rust or blisters are found in 4 or more general areas, and the width of the rust blisters from the cut part exceeds 7 mm. (*)Corrosion resistance (wet surface): The corrosion resistance was evaluated in the same manner as above, except that a 70 x 150 x 3.2 mm sandblasted steel plate was used as the substrate, the plate having been immersed in clean water and then immediately removed from the water. (*)Yellowing Two 300 x 100 x 1 mm steel plates were painted with a brush paint so that the dry film thickness was 150 μm, and then dried at 23 ° C for 7 days to prepare test pieces. One was used as an exposure test piece, and the other was used as a comparison test piece. After carrying out an outdoor exposure test for 24 months using the procedure described in JISK 5600-7-6, the exposure test pieces were visually evaluated for the appearance of the coating according to the following criteria. ◎: No change in the exposed test specimen compared to the comparison specimen. ○: The exposed test piece was slightly yellowed compared to the control test piece, but this was within the practical range. △: Yellowing is clearly observed on the dew test piece. ×: Significant yellowing was observed in the exposed test piece.

Claims

1. The epoxy resin (A), the pigment (B), the polyamine compound (C) and the organic solvent (D) are included, the non-volatile content is within the range of 60 to 99 mass%, and the active hydrogen equivalent ratio of the polyamine compound (C) to 1 equivalent of the epoxy group of the epoxy resin is within the range of 0.4 to 3.0, The pigment (B) contains, as a part of its components, a flake-like pigment containing talc and glass flakes, The amount of glass flakes used is more than 0 and less than 59.9 parts by mass based on 100 parts by mass of the non-volatile content of the epoxy resin (A), The polyamine compound (C) is incompatible with an equal-volume mixture of water and acetone and has an active hydrogen equivalent of 126 or more and 500 or less; the organic solvent (D) contains 40 mass% or more of an organic solvent (D1) specified as a third class organic solvent in the Industrial Safety and Health Act, and does not contain any organic solvent (D2) specified as a second class organic solvent in the Industrial Safety and Health Act, or, if it contains any one of the organic solvents (D2), the content of any one of the organic solvents (D2) is less than 5.0 mass% in the organic solvent (D); and, if the organic solvent (D2) is a combination of multiple organic solvents, the content of each of the multiple organic solvents (D2) in the organic solvent (D) is less than 5 mass%; the organic solvent (D1) is at least one selected from the group consisting of gasoline, coal tar naphtha, petroleum ether, petroleum naphtha, petroleum benzine, turpentine, mineral spirits, and combinations thereof; An anticorrosion coating composition for wet surfaces, wherein the organic solvent (D2) is at least one selected from acetone, isobutyl alcohol, isopropyl alcohol, isopentyl alcohol, ethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-butyl ether, ethylene glycol monomethyl ether, ortho-dichlorobenzene, xylene, cresol, chlorobenzene, isobutyl acetate, isopropyl acetate, isopentyl acetate, ethyl acetate, n-butyl acetate, n-propyl acetate, n-pentyl acetate, methyl acetate, cyclohexanol, cyclohexanone, N,N-dimethylformamide, tetrahydrofuran, trichloroethane, toluene, n-hexane, 1-butanol, 2-butanol, methanol, methyl ethyl ketone, methylcyclohexanol, methylcyclohexanone, methyl-n-butyl ketone, and combinations thereof (excluding those in which the content of stannous sulfate is 2.0 to 8.0 parts by mass per 100 parts by mass of the coating composition).

2. 2. The anticorrosive coating composition according to claim 1, wherein the epoxy resin (A) is a modified epoxy resin having a number average molecular weight of 900 or more.

3. 3. The anticorrosive coating composition according to claim 1, wherein the pigment (B) contains an antirust pigment as a part of its components.

4. The anticorrosive coating composition according to claim 1 , further comprising a silane coupling agent.

5. 5. The anticorrosive coating composition according to claim 1, wherein the coating form is a two-component composition comprising a base component containing an epoxy resin (A) and a pigment (B) and a curing agent component containing a polyamine compound (C), and the base component and / or the curing agent component contains an organic solvent (D).

6. 5. The anticorrosive coating composition according to claim 4, wherein the coating form is a two-component composition comprising a base component containing an epoxy resin (A) and a pigment (B) and a curing agent component containing a polyamine compound (C), the base component and / or the curing agent component containing an organic solvent (D), and the base component and / or the curing agent component containing a silane coupling agent.

7. A method for anticorrosive coating on a wet surface, comprising coating the anticorrosive coating composition according to any one of claims 1 to 6 on the wet surface.

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