Method for repairing coating film provided on ship or underwater structure

Abstract

The present invention pertains to a method for repairing a coating film provided on a ship or an underwater structure, the method comprising: a step (1) in which a sealing layer is formed on the surface of the coating film provided on the ship or the underwater structure; and a step (2) in which an antifouling layer is formed on the sealing layer, the sealing layer being formed using an aqueous sealing composition containing an aqueous resin and water, and the antifouling layer being formed using an antifouling layer coating material containing a resin and an organic solvent.

Description

Technical Field

[0001] The invention relates to a method for repairing a coating film arranged on a ship or an underwater structure. Background Art

[0002] Since ships and underwater structures are exposed to water for a long time, aquatic organisms such as oysters and barnacles attach to the bottom of the ship and the surface of the structure, increasing the underwater resistance and causing a decrease in the speed and fuel efficiency of the ship.

[0003] In order to suppress this phenomenon, after applying the base antirust paint on ships and underwater structures, a special paint called antifouling paint composition [AF (Anti-Fouling) paint] is applied as a top coat. By applying the antifouling paint composition, the bottom of the ship and the surface of the underwater structure are given the property of being difficult for aquatic organisms to adhere, that is, the antifouling property.

[0004] However, when the bottom of a ship is exposed to water for a long time and is subject to water flow resistance, the antifouling coating film is gradually consumed, damaged or peeled off, making it difficult to maintain the antifouling performance. Therefore, it is necessary to regularly perform repair coating to re-apply a new antifouling coating composition. In addition, when the old coating film on the surface of the substrate is removed in advance before the repair coating, a lot of labor and time are required, so a new coating is directly applied on the old coating film.

[0005] For example, Patent Document 1 discloses a method for restoring the decontamination effect of a damaged decontamination coating area on a metal substrate, comprising: (a) treating the damaged decontamination coating area with an effective amount of a two-component condensation-curing silicone RTV (room temperature curing) adhesion promoter composition under atmospheric conditions, the adhesion promoter composition comprising (i) a silanol-terminated polydiorganosiloxane and (ii) 0.5 wt % to 5.5 wt % of an aminoalkyltrialkoxysilane based on the weight of the silanol-terminated polydiorganosiloxane; and (b) applying the two-component condensation-curing silicone RTV (room temperature curing) decontamination coating composition as a top coat on the area treated in (a) above.

[0006] Patent Document 2 discloses a method of applying a tar epoxy rust-proof paint, further applying a tar vinyl sealant paint, and then applying a biofouling prevention coating composition using a copolymer containing an organosilyl monomer and a hemiacetal ester group-containing monomer thereon.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2000-197851

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 8-199095 Summary of the invention

[0011] Problems to be solved by the invention

[0012] However, in the methods described in Patent Documents 1 and 2, the coating film of the lower layer becomes a fragile layer, and peeling may occur after the application of the repair paint. In addition, the antifouling layer paint for repair takes a long time to dry after application, and it is desired to improve this.

[0013] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for repairing a coating film provided on a ship or an underwater structure, which can provide an antifouling layer having good drying properties and excellent peeling resistance.

[0014] Means for solving problems

[0015] The inventors of the present invention have conducted in-depth research on the above-mentioned subject and found that, before applying the antifouling coating for repair coating, the coating film before repair is treated with a water-containing aqueous sealing composition, thereby significantly improving the drying property and peeling resistance of the antifouling layer formed by the subsequent repair coating.

[0016] That is, the present invention relates to a method for repairing a coating film provided on a ship or an underwater structure as follows.

[0017] A method for repairing a coating film disposed on a ship or an underwater structure, comprising:

[0018] Step (1), forming a sealing layer on the surface of a coating film provided on a ship or an underwater structure; and

[0019] Step (2), forming an antifouling layer on the sealing layer,

[0020] wherein the sealing layer is formed using an aqueous sealing composition comprising an aqueous resin and water,

[0021] The antifouling layer is formed using an antifouling layer coating material containing a resin and an organic solvent.

[0022] Effects of the Invention

[0023] According to the coating film repairing method of the present invention, an antifouling coating film having excellent peeling resistance can be formed on the coating film before repairing. In addition, the coating film repairing method of the present invention has the advantage of short working time because the antifouling layer is excellent in drying when formed. DETAILED DESCRIPTION

[0024] <Coating repair method>

[0025] The coating film repair method according to the embodiment of the present invention (hereinafter also described as the present embodiment) is applied to a ship or an underwater structure.

[0026] Examples of ships include passenger ships, cargo ships, tankers, fishing boats, boats, yachts, etc., and examples of underwater structures include water supply and drainage outlets of thermal power plants or nuclear power plants, sluice gates, bridge piers, port facilities, submarine tunnels, canals, waterways, etc. In the present invention, the above-mentioned ships and underwater structures, such as repair ships, etc., have a coating film (old coating film) on the surface before repair. There is no restriction on the degree of residue of the old coating film, and it can be a partial residue or a complete residue. In the case where the rupture and peeling of the old coating film are relatively obvious, a process of simply removing the old coating film can be implemented before implementing the subsequent sealing layer formation process.

[0027] <Coating before repair (old coating)>

[0028] In the present invention, the old coating film is not limited to the type of coating, as long as it is a coating film that has been installed on the above-mentioned ship or underwater structure, it can be a single layer or a multi-layer structure, and the outermost layer is an antifouling layer. In the case where the old coating film is a multi-layer structure, more than one coating film can be provided on the lower side of the antifouling layer.

[0029] The antifouling layer is a coating film formed by a conventionally known antifouling paint, for example, a coating film formed by an antifouling paint selected from a hydrolyzable antifouling paint, a hydration-decomposition type antifouling paint, and a silicone type antifouling paint. As the antifouling layer, a coating film formed by a hydrolyzable antifouling paint or a hydration-decomposition type antifouling paint is preferred, and a coating film formed by a silyl polymer antifouling paint or a metal acrylic resin antifouling paint having a metal carboxylate structure is particularly preferred. These coatings have a high degree of biological adhesion prevention and a long durability, but also because of this, the peeling property after repair coating is significant. In the present invention, when the antifouling layer is a coating film formed by a hydrolyzable antifouling paint or a hydration-decomposition type antifouling paint, especially a coating film formed by a silyl polymer antifouling paint or a metal acrylic resin antifouling paint as a hydrolyzable antifouling paint, it can significantly exert the effect of preventing peeling after repair coating, so it is preferred.

[0030] Examples of the silyl polymer contained in the silyl polymer-based antifouling paint include copolymers of a polymerizable unsaturated monomer having a triorganosilyl ester group (also referred to as a (triorgano-substituted) silyl ester group) and other polymerizable unsaturated monomers.

[0031] As the polymerizable unsaturated monomer having a triorganosilyl ester group, a polymerizable unsaturated monomer having a triisopropylsilyl group is preferred. As specific examples, for example, triisopropylsilyl (meth)acrylate, triisopropylsilyl 4-pentenoate, bis(triisopropylsilyl) maleate, methyl triisopropylsilyl maleate, ethyl triisopropylsilyl maleate, n-butyl triisopropylsilyl maleate, isobutyl triisopropylsilyl maleate, tert-butyl triisopropylsilyl maleate, n-pentyl triisopropylsilyl maleate, isopentyl triisopropylsilyl maleate, 2-ethylhexyl triisopropylsilyl maleate, Cyclohexyl triisopropylsilyl maleate, bis(triisopropylsilyl) fumarate, methyl triisopropylsilyl fumarate, ethyl triisopropylsilyl fumarate, n-butyl triisopropylsilyl fumarate, isobutyl triisopropylsilyl fumarate, n-pentyl triisopropylsilyl fumarate, isopentyl triisopropylsilyl fumarate, 2-ethylhexyl triisopropylsilyl fumarate, cyclohexyl triisopropylsilyl fumarate, and combinations thereof, with triisopropylsilyl (meth)acrylate being particularly preferred.

[0032] Examples of other polymerizable unsaturated monomers include: alkyl (meth)acrylate compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate; alkoxyalkyl (meth)acrylate compounds such as 2-methoxyethyl (meth)acrylate, 2-methoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 2-ethoxyethyl (meth)acrylate; ethylene glycol monomethyl (meth)acrylate, (meth)acrylate having a polyoxyethylene chain with an alkoxy group at one molecular end, and (meth)acrylate having a polyoxypropylene chain with an alkoxy group at one molecular end. , (meth)acrylate alkylene glycol alkyl ester compounds such as propylene glycol monomethyl (meth)acrylate; (meth)acrylate 2-hydroxyethyl ester, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, ε-caprolactone modified monoester of (meth)acrylic acid and a diol having 2 to 8 carbon atoms, allyl alcohol, (meth)acrylate having a polyoxyethylene chain with a hydroxyl group at the molecular end, and the like; styrene; vinyl toluene; vinyl compounds such as α-methylstyrene, vinyl propionate, and vinyl acetate; carboxyl-containing polymerizable unsaturated compounds such as (meth)acrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, crotonic acid, and β-carboxyethyl (meth)acrylate; etc.

[0033] In this specification, "(meth)acrylate" means acrylate or methacrylate, "(meth)acrylic acid" means acrylic acid or methacrylic acid, "(meth)acryl" means acrylyl or methacrylyl, and "(meth)acrylamide" means acrylamide or methacrylamide.

[0034] As the metal acrylic resin, for example, reaction products of (meth) acrylic acid, other polymerizable unsaturated monomers and divalent metal compounds can be cited. In the reaction, water and organic solvents can be used as needed. It is believed that the carboxyl group of (meth) acrylic acid reacts with the divalent metal to introduce a metal carboxylate structure into the acrylic resin. As the other polymerizable unsaturated monomers, compounds other than (meth) acrylic acid can be cited among the compounds exemplified as other polymerizable unsaturated monomers in the description of the silyl polymer.

[0035] Examples of the divalent metal compound include oxides or hydroxides of metals such as copper, zinc, calcium, magnesium, and iron.

[0036] Examples of the hydration-decomposable antifouling paint include an antifouling paint containing a hydration-decomposable acrylic resin, such as a resin obtained by copolymerizing an alkoxyalkyl (meth)acrylate compound and other polymerizable unsaturated monomers. Examples of the alkoxyalkyl (meth)acrylate compound include the above-mentioned compounds, and examples of the other polymerizable unsaturated monomers include compounds other than the alkoxyalkyl (meth)acrylate compound among those exemplified as other polymerizable unsaturated monomers in the description of the silyl polymer.

[0037] The antifouling paint may contain various components generally used in antifouling paints, such as an antifouling agent, rosin, a coloring pigment, an extender pigment, a dehydrating agent, a plasticizer, a thixotropic agent (anti-sagging agent), a defoaming agent, and an organic solvent.

[0038] In the coating repair method of the present embodiment, the old coating may have any single-layer coating or composite coating on the lower side of the antifouling layer. As the coating on the lower side, in the case of a single-layer coating, for example, an epoxy resin coating can be cited, and in the case of a composite coating, a coating comprising a vinyl resin coating and an epoxy resin coating can be cited. By making the epoxy resin coating the coating on the lower side, the rust resistance of the substrate can be improved, and the adhesion with the antifouling layer can be improved. In addition, from the viewpoint of adhesion, the vinyl resin coating is preferably arranged between the antifouling coating and the epoxy resin coating.

[0039] As the epoxy resin coating film, a coating film formed by an epoxy resin paint is preferred. The epoxy resin coating film may be a single layer or a composite coating film formed by laminating layers of different components, such as an adhesive coating layer and a primer layer. The epoxy resin paint generally contains an epoxy resin and a polyamine compound.

[0040] Examples of the epoxy resin include bisphenol A epoxy resin, bisphenol F epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, phenol novolac epoxy resin, cresol epoxy resin, dimer acid-modified epoxy resin, aliphatic epoxy resin, and alicyclic epoxy resin.

[0041] Examples of the polyamine compound include aliphatic polyamines such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and poly(oxypropylene)diamine; aromatic polyamines such as xylylenediamine, diaminodiphenylmethane, and phenylenediamine; alicyclic polyamines such as 1,3-bisaminomethylcyclohexane and isophoronediamine; and modified products of these polyamines, such as epoxy adducts, ketimines, polyamide amines, Mannich compounds, and Michael addition compounds. Epoxy adducts and dimer acid-modified products of the above-mentioned polyamide amines may also be mentioned.

[0042] As the vinyl resin coating film, a coating film formed by a vinyl resin coating is preferred. The vinyl resin coating generally contains a vinyl resin. Examples of the vinyl resin include resins obtained by copolymerizing vinyl monomers such as vinyl chloride, vinyl acetate, vinyl alcohol, styrene, and ethylene.

[0043] The above-mentioned epoxy resin coating film or vinyl resin coating film may contain various components used in general coatings, such as modifying resins other than epoxy resins or vinyl resins, extender pigments, coloring pigments, rust-proof pigments, curing accelerators, plasticizers, thixotropic agents (anti-sagging agents), dispersants, etc.

[0044] Next, a coating film repairing method according to an embodiment of the present invention will be described.

[0045] <Sealing layer forming step (1)>

[0046] The process (1) in the coating repair method of the embodiment of the present invention is a process of forming a sealing layer on the surface of the coating provided on the above-mentioned ship or underwater structure. The present invention is characterized in that a water-based sealing composition comprising an aqueous resin and water is used to form the sealing layer. By using an aqueous sealing composition comprising water as a dilution medium, the crack resistance and peeling resistance of the antifouling layer formed in the next process are improved, and the drying property of the coating for the antifouling layer is effectively improved. Although the reason is not clear, it is speculated that the old coating becomes fragile due to years of deterioration, and the applied aqueous sealing composition penetrates into the deteriorated old coating, thereby improving the physical properties of the old coating and improving the adhesion to the substrate and the antifouling layer. When a sealing composition comprising an organic solvent as a dilution medium is applied, the effect of improving the crack resistance and peeling resistance of the antifouling layer after the repair coating becomes poor, because it is not suitable.

[0047] As the aqueous resin contained in the aqueous sealing composition, a water-soluble resin or a water-dispersible resin is used. In this specification, a water-soluble resin refers to a resin that dissolves in water and is a resin whose aqueous resin solution becomes transparent when visually observed. In addition, in this specification, a water-dispersible resin refers to a resin that exists when dispersed in water and whose aqueous resin dispersion becomes turbid when visually observed.

[0048] As the water-based resin, specifically, for example, acrylic resin, vinyl resin, polyolefin resin, silicon resin, polyurethane resin, epoxy resin, phenolic resin, polyester resin, alkyd resin, polycarbonate resin, polyisocyanate compound, polyamine compound and their combination etc. can be cited. In addition, it can also be a resin obtained by modification or graft polymerization of two or more of these resins. In addition, when the above-mentioned resin is in the form of dispersed particles, it can be any one of the multilayers such as monolayer or core-shell type.

[0049] As the aqueous resin, epoxy resins and acrylic resins are preferred from the viewpoint of crack resistance and peeling resistance of the antifouling layer after repair coating, and among them, aqueous epoxy resins and aqueous acrylic resins are useful.

[0050] As the water-based epoxy resin, a resin obtained by emulsifying and dispersing an epoxy resin having an epoxy group in an aqueous medium is preferred. As the epoxy resin, the same compounds as those exemplified in the description of the old coating film can be exemplified. From the viewpoint of the peeling resistance and drying property of the antifouling layer after the repair coating, the epoxy equivalent is preferably within the range of 1000 g / eq or less, and more preferably within the range of 100 to 800 g / eq.

[0051] The epoxy equivalent refers to the number of grams (g / eq) of a resin containing 1 gram equivalent of epoxy groups, and refers to the epoxy equivalent measured according to the value announced by the manufacturer or JIS K 7236 (2009).

[0052] Examples of the waterborne epoxy resin include resins obtained by emulsifying and dispersing the above epoxy resins in the presence of an emulsifying component derived from polyoxyalkylenes. Examples of the above emulsifying component derived from polyoxyalkylenes include polyoxyalkylene alkyl ether compounds such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene tridecyl ether, and polyoxyethylene oleyl ether; polyoxyalkylene alkyl phenyl ether compounds such as polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenyl ether; polyoxyalkylene polycyclic phenyl ether compounds such as polyoxyethylene polycyclic phenyl ether; polyoxyalkylene alkyl ester compounds such as polyoxyethylene monolaurate, polyoxyethylene monostearate, and polyoxyethylene monooleate; sorbitan compounds such as polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbitan monooleate; nonionic polyoxyalkylene compounds such as polyethylene glycol and polypropylene glycol; epoxy-modified polyoxyalkylene compounds obtained by modifying the above polyoxyalkylene compounds with the above epoxy resin; and combinations thereof.

[0053] Examples of the epoxy-modified polyoxyalkylene compound include polyethylene glycol, epoxy resins having a hydroxyl group and an epoxy group, monohydric alcohols, and reaction products of compounds having at least two isocyanate groups in one molecule.

[0054] Examples of the epoxy resin having a hydroxyl group and an epoxy group include bisphenol-type epoxy resins such as bisphenol A-type epoxy resin and bisphenol F-type epoxy resin, and bisphenol A-type epoxy resin is particularly preferred.

[0055] The monohydric alcohol is used to block the isocyanate group in the modified epoxy resin, and examples thereof include monohydric alcohols such as ethanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.

[0056] As a compound having at least two isocyanate groups in one molecule, aliphatic, alicyclic or aromatic polyisocyanate compounds known per se can be used, for example, hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated 4,4-diphenylmethane diisocyanate, toluene diisocyanate, xylylene diisocyanate, and the like, as well as biuret compounds and isocyanurate compounds of these polyisocyanate compounds; and combinations thereof, etc.

[0057] The epoxy-modified product of the polyoxyalkylene compound can be produced by a method known per se, for example, by mixing the above-mentioned components and reacting them until unreacted isocyanate groups are substantially eliminated.

[0058] The epoxy-modified product of the polyoxyalkylene compound is used as a dispersion stabilizing resin, and the epoxy resin is emulsified and dispersed in an aqueous medium, thereby obtaining a water-dispersible epoxy resin emulsion.

[0059] When the aqueous sealing composition contains an aqueous epoxy resin as an aqueous resin, it is preferably included in an aqueous polyamine compound. As aqueous polyamine compounds, compounds obtained by dispersing or solubilizing polyamine compounds or modified products thereof in water can be cited, and commercially available products can be used. As the above-mentioned polyamine compounds, for example, aliphatic polyamines such as ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, triaminopropane, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, isophoronediamine and 1,3-bisaminomethylcyclohexane; aromatic polyamines such as phenylenediamine, meta-phenylenediamine, para-phenylenediamine and diaminodiphenylmethane; polyoxyethylenediamine, polyoxypropylenediamine, triethylene glycoldiamine and tripropylene glycoldiamine, etc. Examples of modification include amidation, Mannich addition and epoxy addition.

[0060] As the aqueous acrylic resin, one obtained by emulsifying and dispersing an acrylic resin in an aqueous medium is preferred.

[0061] Examples of the acrylic resin include copolymers of polymerizable unsaturated monomers containing an alkyl (meth)acrylate compound. As an emulsification dispersion method, the acrylic resin may be dispersed in an aqueous medium in the presence of an emulsifying component, or a method of emulsifying and polymerizing a polymerizable unsaturated monomer containing an alkyl (meth)acrylate compound in the presence of water and an emulsifying component may be used. Examples of the alkyl (meth)acrylate compound include the compounds exemplified in the description of the old coating film. In addition, examples of other polymerizable unsaturated monomers copolymerizable with the alkyl (meth)acrylate compound include: (meth)acrylate alkylene glycol alkyl ester compounds such as ethylene glycol monomethyl ester, (meth)acrylate having a polyoxyethylene chain with an alkoxy group at one molecular end, (meth)acrylate having a polyoxypropylene chain with an alkoxy group at one molecular end, and propylene glycol monomethyl ester; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate; (Meth)acrylic acid hydroxyalkyl ester compounds such as esters, ε-caprolactone modified products of monoesters of (meth)acrylic acid and diols having 2 to 8 carbon atoms, allyl alcohol, (meth)acrylic acid esters having polyoxyethylene chains with hydroxyl groups at the molecular ends; styrene; vinyl toluene; vinyl compounds such as α-methylstyrene, vinyl propionate, and vinyl acetate; (meth)acrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, crotonic acid, and β-carboxyethyl (meth)acrylate; etc.

[0062] The amount of the aqueous resin contained in the aqueous sealing composition is preferably in the range of 5 to 75 parts by mass, or 10 to 60 parts by mass, based on the mass of the nonvolatile component of the aqueous resin, relative to 100 parts by mass of the aqueous sealing composition during coating.

[0063] In this specification, the nonvolatile matter is a residue after removing volatile components such as an organic solvent, and can be measured in accordance with JIS K5601 1-2 (2008) (heating temperature: 125° C., heating time: 60 minutes).

[0064] Furthermore, the amount of water contained in the aqueous sealing composition is preferably in the range of 20 to 90 parts by mass, or 20 to 60 parts by mass, relative to 100 parts by mass of the aqueous sealing composition.

[0065] In addition to the aqueous resin and water, the aqueous sealing composition may also contain coloring pigments, extender pigments, dispersants, thickeners, defoamers, film-forming aids, preservatives, pH adjusters and other ingredients.

[0066] Examples of the extender pigment include calcium carbonate, talc, barium sulfate, mica, clay, silica, and aluminum hydroxide. From the viewpoint of drying properties and peeling resistance after repair coating, calcium carbonate and talc are preferably contained.

[0067] In the case of including a body pigment, the amount of the body pigment in the aqueous sealing composition is preferably 20 to 60% in terms of pigment volume concentration. The pigment volume concentration is the volume ratio of the pigment to the total non-volatile components of all resin components and all pigments in the coating. The specific gravity of the pigment uses the catalog value. If the catalog value is unclear, the specific gravity of the resin non-volatile component is approximated to 1 based on the "Paint Raw Materials Handbook, 9th Edition" (Japan Paint Industry Association).

[0068] The water-based sealing composition can be applied by general application methods such as brush, roller, air spray, airless spray, etc. Drying after application is usually carried out at room temperature, but forced drying can also be performed as needed. Normal temperature refers to a temperature that varies depending on the atmospheric temperature of the environment in which the application is performed, but no forced heating or cooling or other temperature operations are performed. The drying time is preferably 3 hours to 72 hours, and more preferably 6 hours to 48 hours.

[0069] When the water-based sealing composition is applied to the old coating film, the water-based sealing composition penetrates into the old coating film and forms a sealing layer on the old coating film. The water-based sealing composition is applied so that the film thickness of the formed sealing layer is preferably 10 to 500 μm, more preferably 20 to 250 μm in terms of dry film thickness.

[0070] In this specification, the dry film thickness is a value measured by an electromagnetic film thickness meter.

[0071] <Antifouling layer forming step (2)>

[0072] In the coating film repairing method according to the embodiment of the present invention, the antifouling layer is formed on the sealing layer formed in the above step (1).

[0073] The antifouling layer is formed using an antifouling layer coating material containing a resin and an organic solvent. The antifouling layer coating material is an organic coating material using an organic solvent as a diluent.

[0074] As the resin in the antifouling layer coating, a resin soluble in an organic solvent or a resin dispersible in an organic solvent is used. In this specification, a resin soluble in an organic solvent refers to a resin whose resin solution is transparent when visually observed. In addition, in this specification, a resin dispersible in an organic solvent refers to a resin that is dispersed in an organic solvent and whose resin dispersion is turbid when visually observed.

[0075] Specific examples of the resin include hydrolyzable resins such as silyl polymers, metal acrylic resins having a metal carboxylate structure, hydrolyzable resins, silicone resins, resin acids such as rosin, and combinations thereof, and hydrolyzable resins and / or hydrolyzable resins are preferred.

[0076] Examples of the silyl polymer include the same resins as those exemplified in the description of the old coating film.

[0077] Examples of the resin having a metal carboxylate structure include the same resins as those exemplified in the description of the old coating film.

[0078] Examples of the hydrodecomposable resin include the same hydrodecomposable acrylic resins as those exemplified in the description of the old coating film.

[0079] The amount of the resin contained in the antifouling layer coating material is preferably 10 to 80 parts by mass, particularly preferably 20 to 70 parts by mass, based on 100 parts by mass of the antifouling layer coating material.

[0080] As the organic solvent contained in the antifouling layer coating, any organic solvent known in the coating field can be used, and specific examples thereof include aromatic solvents such as toluene and xylene; ketone solvents such as methyl isobutyl ketone and cyclohexanone; ester solvents; ether solvents such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate; and alcohol solvents such as isopropyl alcohol. The amount of the organic solvent contained in the antifouling layer coating is preferably such that the total non-volatile content of the antifouling layer coating is 20 to 90% by mass.

[0081] In addition to the resin and the organic solvent, the antifouling coating may contain various components generally used in antifouling coatings, such as an antifouling agent, a coloring pigment, an extender pigment, a dehydrating agent, a plasticizer, a thixotropic agent (anti-sagging agent), and a defoaming agent.

[0082] The coating of the antifouling layer can be applied by general coating methods such as brush, roller, air spray, airless spray, etc. Drying after coating is usually carried out at room temperature, but forced drying can also be performed as needed. The drying time is preferably 1 to 14 days, and more preferably about 1 to 7 days is appropriate. The coating film repair method according to the embodiment of the present invention has good drying properties, so the coating film can be fully dried within the above drying time.

[0083] The film thickness of the antifouling layer is preferably 50 to 1000 μm, more preferably 100 to 750 μm in terms of dry film thickness.

[0084] <Adhesive coating forming step>

[0085] In the method for repairing a coating film according to an embodiment of the present invention, after forming a sealing layer in step (1) and before step (2), from the viewpoint of the peeling resistance of the antifouling layer, an adhesive coating can be formed using an adhesive coating paint. The adhesive coating paint is a paint different from the aqueous sealing composition and the antifouling layer paint, and preferably contains a resin and an organic solvent. As the resin, for example, acrylic resins, epoxy resins, vinyl resins, alkyd resins, and polyamine compounds can be cited, preferably containing epoxy resins and polyamine compounds.

[0086] The amount of the nonvolatile component of the resin contained in the adhesive coating material is preferably 10 to 80 parts by mass, particularly preferably 20 to 70 parts by mass, based on 100 parts by mass of the adhesive coating material during coating.

[0087] Examples of the epoxy resin and the polyamine compound include the same epoxy resin and the polyamine compound as exemplified in the description of the old coating film.

[0088] Examples of the organic solvent include the same compounds as those exemplified in the description of the antifouling coating material. The amount of the organic solvent contained in the adhesive coating material is preferably such that the total nonvolatile content of the adhesive coating material is 20 to 90% by mass.

[0089] The adhesive coating paint may contain various components used in paints, such as a coloring pigment, an extender pigment, an anti-rust pigment, a plasticizer, a thixotropic agent (anti-sagging agent), a defoaming agent, and a curing agent.

[0090] The adhesive coating paint can be applied by a general coating method such as a brush, a roller, an air spray, or an airless spray. Drying after coating is usually performed at room temperature, but forced drying can also be performed as required. The drying time is preferably 2 to 48 hours, and more preferably 5 to 24 hours.

[0091] The film thickness of the adhesive coating layer is preferably 10 to 500 μm, more preferably 20 to 250 μm, in terms of dry film thickness.

[0092] <Method for manufacturing a ship or underwater structure having a repaired coating>

[0093] The method for manufacturing a ship or underwater structure having a repaired coating according to an embodiment of the present invention comprises: step (1) of forming a sealing layer on the surface of a coating provided on the ship or underwater structure; and step (2) of forming an antifouling layer on the sealing layer formed by step (1).

[0094] The coating film provided on a ship or underwater structure is an antifouling coating film. The sealing layer is formed using an aqueous sealing composition containing an aqueous resin and water, and the antifouling layer is formed using an antifouling coating material containing a resin and an organic solvent.

[0095] The steps (1) and (2), including preferred embodiments, are the same as those of the method for repairing a coating film provided on a ship or an underwater structure according to the above-described embodiment of the present invention.

[0096] <Ship or underwater structure, coating>

[0097] The ship or underwater structure of the embodiment of the present invention has a coating film formed by the coating film repair method of the embodiment of the present invention. The coating film of the embodiment of the present invention sequentially comprises a coating film before repair (old coating film) having an antifouling coating film, a sealing layer which is a cured product of an aqueous sealing composition, and an antifouling layer. By providing a sealing layer formed by an aqueous sealing composition between the old coating film and the antifouling layer, a repair coating film with greatly improved crack resistance and peeling resistance can be obtained.

[0098] As described above, the following matters are disclosed in this specification.

[0099] [1] A method for repairing a coating film provided on a ship or an underwater structure, comprising:

[0100] Step (1), forming a sealing layer on the surface of a coating film provided on a ship or an underwater structure; and

[0101] Step (2), forming an antifouling layer on the sealing layer,

[0102] wherein the sealing layer is formed using an aqueous sealing composition comprising an aqueous resin and water,

[0103] The antifouling layer is formed using an antifouling layer coating material containing a resin and an organic solvent.

[0104] [2] The method for repairing a coating film according to [1], comprising: after the step (1), a step of forming an adhesive coating on the sealing layer using an adhesive coating paint containing a resin and an organic solvent.

[0105] [3] The method for repairing a coating film according to [1] or [2], wherein the aqueous resin contained in the aqueous sealing composition comprises an aqueous epoxy resin and an aqueous polyamine compound.

[0106] [4] The method for repairing a coating film according to any one of [1] to [3], wherein the aqueous sealing composition contains an extender pigment.

[0107] [5] The coating film repair method according to any one of [1] to [4], wherein the resin contained in the antifouling coating material comprises at least one of a hydrolyzable resin and a hydration-decomposable resin.

[0108] [6] A ship or underwater structure comprising: a coating film formed by the coating film repair method according to any one of [1] to [5].

[0109] [7] A method for manufacturing a ship or underwater structure having a repaired coating, comprising:

[0110] Step (1), forming a sealing layer on the surface of a coating film provided on a ship or an underwater structure; and

[0111] Step (2), forming an antifouling layer on the sealing layer,

[0112] wherein the sealing layer is formed using an aqueous sealing composition comprising an aqueous resin and water,

[0113] The antifouling layer is formed using an antifouling layer coating material containing a resin and an organic solvent.

[0114] [Example]

[0115] Hereinafter, the present invention will be described in further detail by means of production examples, examples and comparative examples, but the present invention is not limited thereto. "Part" in each example means part by mass, and "%" means mass %.

[0116] <Manufacturing of various coating materials for repair coating>

[0117] Production Examples 1 to 15

[0118] Sealing compositions (S-1) to (S-9), adhesive coating materials (BC-1) to (BC-3), and hydrolyzable silyl polymer antifouling coating materials (A-1), hydrated decomposable acrylic resin antifouling coating materials (A-2), and hydrolyzable zinc acrylic resin antifouling coating materials (A-3) as antifouling layer coating materials were prepared according to the formulation compositions shown in Tables 1 to 3. Sealing compositions (S-1) to (S-8) are aqueous sealing compositions, and (S-9) is an organic sealing composition using an organic solvent as a diluent.

[0119]

Table 1

[0120] Mass

[0121]

[0122] 50% epoxy emulsion: a dispersion obtained by dispersing a bisphenol A epoxy resin having an epoxy equivalent of 500 and a reaction product of a bisphenol A epoxy resin, polyethylene glycol, toluene diisocyanate and diethylene glycol monoethyl ether in water, and water

[0123] 50% Acrylic Emulsion: Emulsified polymer containing styrene / methyl methacrylate / 2-ethylhexyl acrylate / vinyl trimethoxysilane / acrylic acid and water

[0124] 60% polyamine: containing water-soluble fatty polyamine with amine value of 335 and water

[0125] Polyamidoamine: amine value 335, organic solvent-based aliphatic polyamine

[0126] Epoxy resin: Bisphenol A epoxy resin with epoxy equivalent of 500

[0127] Calcium carbonate: specific gravity is 2.7

[0128] Talc: specific gravity is 2.8

[0129]

Table 2

[0130] Mass

[0131]

[0132] Epoxy resin: Bisphenol A epoxy resin with epoxy equivalent of 500

[0133] 70% polyamine compound: aliphatic polyamide amine, amine value 155

[0134] Ethylene-vinyl acetate copolymer: vinyl acetate content 41% by mass, weight average molecular weight 142,000

[0135]

Table 3

[0136] (parts by mass)

[0137]

[0138] 60% Silyl polymer: Copolymer of triisopropylsilyl methacrylate / methoxyethyl acrylate / methoxyethyl methacrylate / methyl methacrylate / n-butyl acrylate in xylene

[0139] 60% acrylic resin: copolymer of methoxyethyl acrylate / methyl methacrylate in xylene

[0140] 60% Zinc Acrylate Resin: Zinc Oxide / Methoxyethyl Acrylate / Methyl Methacrylate / Ethyl Acrylate / Methacrylic Acid Reaction Products in Water / Butyl Acetate / N-Butanol

[0141] <Production of old coated boards>

[0142] A commercially available epoxy / amine organic solvent-based two-component anticorrosive paint was applied to a sandblasted steel plate of 300 mm in length × 100 mm in width × 1.6 mm in thickness in a dry film thickness of 200 μm, and dried at 25°C for one day. A commercially available epoxy / amine organic solvent-based two-component adhesive coating paint was applied thereto in a dry film thickness of 100 μm, and dried at 25°C for one day. Furthermore, a commercially available methacrylate-based hydrolyzable antifouling paint, a hydrated decomposition-type acrylic antifouling paint, or a cross-linked zinc acrylic hydrolyzable antifouling paint was applied in a dry film thickness of 250 μm. Then, in order to make the old coating film close to the deteriorated state, it was dried at a high temperature of 40°C for 30 days to obtain an old coating film plate.

[0143] <Repair paint>

[0144] <Example of repair painting after sealing the old paint film to form an antifouling layer>

[0145] [Examples 1 to 16 and Comparative Example 1]

[0146] On the prepared old coating plate, any one of the sealing compositions (S-1) to (S-9) described in Table 4 or Table 5 is applied in a manner of a dry film thickness of 50 μm, and dried at 23°C for 24 hours. Then, any one of the antifouling coatings (A-1) to (A-3) prepared in the above-mentioned manufacturing example is applied in a manner of a dry film thickness of 500 μm, and dried at 23°C for two days to obtain a test coated plate, and its peeling resistance and drying property are evaluated.

[0147] [Comparative Example 2]

[0148] A test coating plate was prepared in the same manner as in Example 1, except that the antifouling coating (A-1) was directly applied on the old coating film without applying the sealing composition (S-1), and its peeling resistance and drying properties were evaluated.

[0149] The results are shown in Tables 4 and 5 below.

[0150]

Table 4

[0151]

[0152]

Table 5

[0153]

[0154] <Example of repair painting by forming an antifouling layer after sealing the old paint film>

[0155] [Examples 17 to 48 and Comparative Example 3]

[0156] On the prepared old coating plate, any one of the sealing compositions (S-1) to (S-9) described in Table 1 was applied in a dry film thickness of 50 μm and dried at 23°C for 24 hours, then any one of the adhesive coating materials (BC-1) to (BC-3) described in Table 2 was applied in a dry film thickness of 100 μm and dried at 23°C for 10 hours, then any one of the antifouling layer coating materials (A-1) to (A-3) described in Table 3 was applied in a dry film thickness of 500 μm and dried at 23°C for two days to obtain a test coated plate, and its peeling resistance and drying property were evaluated.

[0157] [Comparative Example 4]

[0158] A test coated panel was prepared in the same manner as in Example 17 above, except that the adhesive coating paint (BC-2) was directly applied on the old coating film without applying the sealing composition (S-1).

[0159] The results are shown in Tables 6 to 9 below.

[0160]

Table 6

[0161]

[0162]

[0163]

Table 7

[0164]

[0165]

Table 8

[0166]

[0167]

Table 9

[0168]

[0169] <Evaluation Test>

[0170] (*) Peel resistance after repair coating

[0171] A commercially available scratch tester (manufactured by Profid Co., Ltd., trade name: Scoot PF-SCT-02) was used, and a stainless steel indenter was used to move the platform by 80 mm at a speed of 20 mm / sec, while gradually applying a load up to 50 N to damage the test coated plate, thereby measuring the peeling load (load when the steel plate is exposed) and evaluating according to the following criteria. The larger the value of the peeling load (N), the better the peeling resistance from the steel plate.

[0172] S: 50N or more

[0173] A: 40 or more and less than 50N

[0174] B: 30 or more and less than 40N

[0175] C: 20 or more and less than 30N

[0176] D: 10 or more and less than 20N

[0177] E: less than 10N

[0178] (*) Drying properties of antifouling topcoat for repair coating

[0179] The surface of the test coated plate was touched with a finger, and the drying property of the antifouling coating after the repair coating was evaluated according to the following criteria.

[0180] A: There is absolutely no trace on the antifouling layer and no adhesion

[0181] B: There is no trace on the antifouling layer, and there is a slight adhesion

[0182] C: There are slight marks on the antifouling layer and it is slightly adhesive

[0183] D: There are obvious traces of residue on the antifouling layer, and the adhesion is remarkable

[0184] <Inspection>

[0185] The results shown in Tables 4 to 9 show that the repaired coating bodies (Examples 1 to 48) in which the old coating film was treated with the aqueous sealing composition containing water and then coated with the antifouling coating material had good peeling resistance and drying properties of the antifouling layer.

[0186] On the other hand, when the old coating film was treated with an organic solvent-based sealing composition (Comparison Example 1) or when the antifouling layer coating was directly applied to the old coating film without sealing treatment (Comparison Example 2), a repaired coating body with good evaluation results for the peeling resistance and drying properties of the antifouling layer could not be obtained.

[0187] Furthermore, it was confirmed that when the old coating film was treated with the aqueous sealing composition, the peeling resistance and drying properties of the antifouling layer could be maintained even when the antifouling layer coating was applied after the organic solvent-based binder coating (Examples 17 to 48).

[0188] On the other hand, when the old coating film was treated with an organic solvent-based sealing composition and then coated with an organic solvent-based adhesive coating and then coated with an antifouling layer coating (Comparative Example 3), and when the old coating film was directly coated with an organic solvent-based adhesive coating without performing a sealing treatment and then coated with an antifouling layer coating (Comparative Example 4), a repaired coating body with good evaluation results for both the peeling resistance and drying properties of the antifouling layer could not be obtained.

[0189] The present invention is described in detail with reference to specific embodiments, but it is obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on Japanese patent application (Japanese patent application 2023-166334) filed on September 27, 2023, the contents of which are incorporated herein by reference.

Claims

1. A method for repairing a coating film provided on a ship or an underwater structure, comprising the steps of forming a sealing layer on the surface of the coating film provided on the ship or the underwater structure (1), and forming an antifouling layer on the sealing layer (2). in, The sealing layer is formed using an aqueous sealing composition comprising an aqueous resin and water, The antifouling layer is formed using an antifouling layer coating material containing a resin and an organic solvent.

2. The method for repairing a coating film according to claim 1, comprising: after the step (1), forming an adhesive coating on the sealing layer using an adhesive coating paint containing a resin and an organic solvent.

3. The method for repairing a coating film according to claim 1 or 2, wherein: The water-based resin included in the water-based sealing composition includes a water-based epoxy resin and a water-based polyamine compound.

4. The method for repairing a coating film according to claim 1 or 2, wherein: The aqueous sealing composition includes an extender pigment.

5. The method for repairing a coating film according to claim 1 or 2, wherein: The resin contained in the antifouling coating material includes at least one of a hydrolyzable resin and a hydrated decomposable resin. 6 . A ship or underwater structure comprising a coating film formed by the coating film repairing method according to claim 1 or 2 .

7. A method for manufacturing a ship or underwater structure having a repaired coating film, comprising the steps of forming a sealing layer on the surface of a coating film provided on the ship or underwater structure (1), and forming an antifouling layer on the sealing layer (2), in, The sealing layer is formed using an aqueous sealing composition comprising an aqueous resin and water, The antifouling layer is formed using an antifouling layer coating material containing a resin and an organic solvent.

Images