Coating composition

Abstract

Embodiments of the present invention relate to a coating composition, a coating film, a laminated coating film, and a method for manufacturing the same, the coating composition comprising an acrylic resin (A) containing a tertiary amino group and a resin (B) containing a carboxyl group, or comprising an acrylic resin (AB) containing a tertiary amino group and a carboxyl group, and an epoxy group-containing silane compound (C) and an epoxy resin (D) other than an epoxy group-containing acrylic resin.

Description

Technical Field

[0001] One embodiment of the present invention relates to a coating composition, a coating film, a substrate with a laminated coating film, and a method for producing the same. Background Art

[0002] Ships, bridges, storage tanks, integrated equipment, offshore buoys, pipelines and other (large) steel structures are usually coated with a primer coating such as an epoxy resin anticorrosive coating composition for the purpose of corrosion protection, and then a topcoat coating composition is applied on the formed primer coating for the purpose of improving aesthetics and weather resistance.

[0003] As the topcoat coating composition, a two-component reaction-curing type topcoat coating composition (for example, an acrylic urethane resin coating composition, a fluorourethane resin coating composition) is known.

[0004] Since such conventional topcoat coating compositions contain compounds having isocyanate groups, or compounds having isocyanate groups are used in the preparation stage of the coating compositions, there is a need to reduce the load on the human body and the environment during coating and when preparing the coating compositions.

[0005] Therefore, as a top coating composition that takes the human body and the environment into consideration when coating, a top coating composition that does not contain a compound having an isocyanate group, specifically, a polysiloxane resin coating composition is known.

[0006] It is known that although polysiloxane resin coating compositions can generally form coatings having high coating hardness, there is still room for improvement in terms of the balance between coating hardness and bending resistance, weather resistance and / or chemical resistance.

[0007] Regarding these aspects, Patent Document 1 describes a coating composition comprising a tertiary amino group-containing acrylic resin, a carboxyl group-containing resin, and an epoxy group-containing silane compound as a coating composition capable of forming a coating film having excellent weather resistance and the like.

[0008] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2021-155597 Summary of the invention

[0009] Problems to be solved by the invention When the coating composition described in the above-mentioned patent document 1 is used as a topcoat coating composition, although the topcoat coating composition is formed on a primer coating film, after repeated in-depth research by the present inventors, it was found that there is still room for improvement in the adhesion between the topcoat coating composition and the epoxy resin primer coating film.

[0010] In addition, it is known that the appearance (design) of the topcoat film formed on the substrate deteriorates due to aging, etc. As a method for improving the appearance of such an aged coating film (old coating film), it is also possible to peel off the old coating film and re-form the topcoat film. However, since peeling off the old coating film and forming a new topcoat film is time-consuming and laborious, a new topcoat coating composition is directly applied on the old coating film, especially a coating composition that is the same as the coating composition used when forming the old coating film (hereinafter also referred to as "re-coating of the old coating film").

[0011] It is known that when recoating an old coating film in this way, when a conventional topcoat coating composition is used, the adhesion between the old coating film and the coating film (new coating film) formed by the reapplied coating composition (hereinafter also referred to as "adhesion between the old coating film and the new coating film") is insufficient.

[0012] One embodiment of the present invention provides a coating composition capable of forming a coating film having excellent weather resistance and curing properties and excellent adhesion to an epoxy resin-based primer coating film and adhesion between an old coating film and a new coating film.

[0013] Technical solutions to solve problems The present inventors have conducted intensive studies on a method for solving the above-mentioned problems, and have found that the above-mentioned problems can be solved according to the following configuration examples.

[0014] The composition examples of the present invention are as follows.

[0015] <1> A coating composition, wherein comprising an acrylic resin (A) containing a tertiary amino group and a resin (B) containing a carboxyl group, or comprising an acrylic resin (AB) containing a tertiary amino group and a carboxyl group, The present invention also includes an epoxy resin (D) other than an epoxy group-containing silane compound (C) and an epoxy group-containing acrylic resin.

[0016] <2> according to <1> The coating composition, wherein the mass ratio of the content of the epoxy group-containing silane compound (C) to the content of the epoxy resin (D) (the content of the silane compound (C): the content of the epoxy resin (D)) is 1:7 to 7:1.

[0017] <3> according to <1> or <2> The coating composition further contains a silicone resin (E).

[0018] <4> according to <1> ~ <3> The coating composition described in any one of the preceding claims, wherein the coating composition is applied on an epoxy resin-based primer coating film.

[0019] <5> A coating film, wherein the coating film is composed of <1> ~ <4> The coating composition described in any one of the above is formed.

[0020] <6> A substrate with a laminated coating film, comprising, in order, a substrate, an epoxy resin primer coating film and <5> The coating film.

[0021] <7> A method for producing a substrate with a laminated coating film, comprising the following steps [1] and [2]: [1] Based on <1> ~ <4> A step of applying the coating composition described in any one of the above on a substrate having an epoxy resin primer coating film formed thereon, [2] A step of drying the applied coating composition to form a coating film.

[0022] Effects of the Invention According to one embodiment of the present invention, a coating film having excellent weather resistance and curing performance and excellent adhesion to an epoxy resin-based primer coating film and between an old coating film and a new coating film can be formed.

[0023] Furthermore, according to one embodiment of the present invention, a weather-resistant coating composition having excellent drying performance and curable at room temperature can be provided at low cost, and a coating film having a good balance between coating film hardness and bending resistance and excellent chemical resistance can be formed.

[0024] Moreover, according to one embodiment of the present invention, since a coating composition can be formed that does not contain or does not use a compound having an isocyanate group that is harmful to the human body and the environment, a coating composition that has a smaller load on the human body and the environment during coating and during preparation of the coating composition can be formed. DETAILED DESCRIPTION

[0025] <<Coating composition>> A coating composition according to one embodiment of the present invention (hereinafter also referred to simply as “the present composition”) comprises an acrylic resin (A) containing a tertiary amino group and a resin (B) containing a carboxyl group, or comprises an acrylic resin (AB) containing a tertiary amino group and a carboxyl group, and comprises an epoxy group-containing silane compound (C) and an epoxy resin (D) other than the acrylic resin containing an epoxy group.

[0026] That is, the composition of the present invention is A coating composition (hereinafter also referred to as "composition 1") comprising an acrylic resin (A) containing a tertiary amino group, a resin (B) containing a carboxyl group, a silane compound (C) containing an epoxy group, and an epoxy resin (D) other than an acrylic resin containing an epoxy group, or A coating composition (hereinafter also referred to as "composition 2") comprising an acrylic resin (AB) containing a tertiary amino group and a carboxyl group, a silane compound (C) containing an epoxy group, and an epoxy resin (D) other than an acrylic resin containing an epoxy group. Among them, composition 1 is preferred from the perspective of being able to easily form a coating film having better weather resistance and curing properties.

[0027] In addition, hereinafter, the acrylic resin (A) containing a tertiary amino group is also referred to as "component (A)". Other components are also referred to as "components-" in the same manner.

[0028] The composition of the present invention can be easily cured even under dry conditions at room temperature, and can form a coating having excellent weather resistance over a long period of time even under harsh environments such as anti-corrosion coating construction.

[0029] Since the composition of the present invention can be cured at room temperature, even if the substrate to be coated is a substrate with poor heat resistance (a substrate with a coating film with poor heat resistance), a coating film can be formed by the composition of the present invention regardless of the type of substrate. In addition, since the composition of the present invention can form a weather-resistant coating film with long-term weather resistance, the period before re-coating can be extended, and even if re-coating is performed on an old coating film, the adhesion between the old coating film and the new coating film is also excellent. Therefore, by using the composition of the present invention, the maintenance cost related to coating of substrates such as steel components can be greatly reduced.

[0030] From the perspective of better exerting the effects of the composition of the present invention, the composition of the present invention is usually preferably applied as a topcoat coating composition, especially as a coating composition (topcoat coating composition) applied on the epoxy resin primer coating film, to the outermost surface of the substrate (the surface on the opposite side to the substrate). In addition, the composition of the present invention can also be used as a mid-upper coating coating that serves as both an intermediate coating coating and a topcoat coating.

[0031] Although the composition of the present invention may be a water-based paint in consideration of the load on the human body and the environment, it is preferably a solvent-based paint because the drying and curing properties of (water-based paint) in low temperature environments (e.g., below 5°C) are often insufficient.

[0032] When the composition of the present invention contains water, the water content is preferably 5% by mass or less, more preferably less than 3.5% by mass, and further preferably 3% by mass or less, relative to 100% by mass of the non-volatile components of the composition of the present invention. The lower limit is, for example but not particularly limited to, 0.1% by mass or more.

[0033] The composition of the present invention may be a one-component composition, but in view of storage stability and easy storage, it is preferably a multi-component composition containing a main agent and a curing agent, for example, preferably a two-component composition containing a main agent containing components (A) and (B) or a main agent containing components (AB) and a curing agent containing the above components (C) and (D). In addition, the composition of the present invention may also be a three-component or more composition containing a third component other than the above main agent and curing agent.

[0034] These main agent, curing agent and third component are usually used in a manner of being preserved, stored, transported, etc. in separate containers and then mixed immediately before use.

[0035] <Tertiary amino group-containing acrylic resin (A)> Component (A) is a resin other than component (B) and component (AB), that is, a resin not containing a carboxyl group, and is not particularly limited as long as it has at least one tertiary amino group per molecule.

[0036] Since component (A) contains a tertiary amino group, the reaction of component (B) with component (C) and / or component (D) can be promoted.

[0037] The component (A) used in the composition of the present invention may be one kind or two or more kinds.

[0038] It should be noted that the "acrylic resin" in this specification refers to acrylic resin and / or methacrylic resin. In addition, "(meth)acrylic group" is a general term for acrylic group and methacrylic group. Similar expressions have similar meanings.

[0039] Component (A) can be synthesized by (co)polymerizing, for example, an unsaturated monomer (a-1) containing a tertiary amino group by a known method, and specifically, can be synthesized by free radical (co)polymerizing an unsaturated monomer (a-1) containing a tertiary amino group and other unsaturated monomers (a-2) as required. At least one of the monomers used in the (co)polymerization is a compound having a (meth)acryloyl group.

[0040] Furthermore, component (A) may be synthesized by free radical (co)polymerization of other unsaturated monomers (a-2) (wherein at least one compound having a (meth)acryloyl group is used as the monomers (a-2)) followed by modification, etc., so that the final obtained resin has a tertiary amino group.

[0041] Component (A) can be synthesized by a conventional method, specifically, by reacting monomers in the presence of a polymerization initiator and a solvent. Examples of the monomer (a-1) include Dialkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dipropylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, diethylaminopropyl (meth)acrylate, and dimethylaminobutyl (meth)acrylate; (Meth)acrylamides containing tertiary amino groups such as N,N-dimethyl (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylamide, N,N-diethylaminoethyl (meth)acrylamide, N,N-dipropylaminoethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, and N,N-dimethylaminobutyl (meth)acrylamide; Vinyl ethers containing tertiary amino groups such as dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, dimethylaminopropyl vinyl ether, and dimethylaminobutyl vinyl ether; Aromatic unsaturated monomers containing a tertiary amino group such as vinylpyridine.

[0042] The above-mentioned monomer (a-1) may be used alone or in combination of two or more.

[0043] As the monomer (a-1), from the viewpoints of stability of the component (A), reactivity with epoxy group-containing compounds (e.g., components (C) and (D), etc., dialkylaminoalkyl (meth)acrylates are preferred, and dimethylaminoethyl (meth)acrylate and diethylaminoethyl (meth)acrylate are more preferred.

[0044] From the viewpoints of easily obtaining a composition having excellent drying and / or curing properties and easily forming a coating film having excellent chemical resistance, water resistance and coating film hardness, etc., the amount of the monomer (a-1) used is preferably 1% by mass or more, more preferably 2% by mass or more, and is preferably 30% by mass or less, more preferably 20% by mass or less, based on 100% by mass of the total amount of the monomers used in synthesizing the component (A).

[0045] Examples of the monomer (a-2) include (Meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, ethylene glycol di(meth)acrylate and other alkylene glycol di(meth)acrylates; (Meth)acrylates containing hydroxyl groups such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, mono(meth)acrylate of cyclohexanedimethanol, polyoxyalkylene glycol (meth)acrylates such as diethylene glycol (meth)acrylate (the number of carbon atoms of the alkylene group is 2 to 4 and the number of moles of the added oxyalkylene group is 1 to 50), and caprolactone-modified hydroxy (meth)acrylate; Unsaturated monomers containing anhydride groups such as maleic anhydride and itaconic anhydride; Unsaturated monomers containing amide groups, such as N-butoxymethyl (meth) acrylamide, (meth) acrylamide, diacetone (meth) acrylamide, and N-hydroxymethyl (meth) acrylamide; Unsaturated monomers containing vinyl groups, such as styrene, vinyl toluene, α-methylstyrene, vinyl acetate, and vinyl benzoate; Unsaturated monomers containing cyano groups, such as acrylonitrile and methacrylonitrile; Unsaturated monomers containing sulfonic acid groups such as styrene sulfonic acid; Unsaturated monomers containing sulfonamide groups, such as p-styrenesulfonamide and N-methyl-p-styrenesulfonamide; Fluorinated vinyl monomers; Ultraviolet absorbing unsaturated monomers (R-UVA) such as 2-[2'-hydroxy-5'-(methacryloyloxymethyl)phenyl]-2H-benzotriazole and 2-[2'-hydroxy-5'-(methacryloyloxyethyl)phenyl]-2H-benzotriazole; Light-stable unsaturated monomers (R-HALS) such as 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine and 4-(meth)acrylamido-2,2,6,6-tetramethylpiperidine.

[0046] The above-mentioned monomer (a-2) may be used alone or in combination of two or more.

[0047] The monomer (a-2) is preferably methyl (meth)acrylate, n-butyl (meth)acrylate, or styrene, because a coating film having well-balanced weather resistance, flexibility (bending resistance), and glossiness can be easily formed.

[0048] From the viewpoints of being able to easily obtain a composition having excellent drying and / or curing properties, and being able to easily form a coating film having excellent chemical resistance, water resistance, and coating film hardness, the amount of the monomer (a-2) used is preferably 70% by mass or more, more preferably 80% by mass or more, and is preferably 99% by mass or less, more preferably 98% by mass or less, based on 100% by mass of the total amount of the monomers used in synthesizing the component (A).

[0049] The glass transition temperature (Tg) of component (A) is preferably -5°C or higher, more preferably 0°C or higher, and preferably 50°C or lower, more preferably 40°C or lower, from the perspective of being able to form a coating film that has a good balance between coating film hardness and bending resistance and is less likely to cause blocking, cracking, etc.

[0050] In the present invention, the Tg is based on the value published by Fox TG in the Bulletin of the American Physical Society, Vol. 1, No. 3, p. 123 in 1956 (Fox TG, Bull. Am. Physics Soc. 1, 3, Page123 (1956)) is approximated by the following Fox equation.

[0051] It should be noted that the resin contains the following literature which does not record Tg (Tg n ) in the case of structural units of monomers with unknown Tg, when the total amount of structural units derived from the monomers with unknown Tg is less than 10 mass%, Tg is calculated using only monomers with known Tg; and when the total amount of structural units derived from the monomers with unknown Tg exceeds 10 mass%, Tg of the resin can be measured by DSC (differential scanning calorimetry) or the like.

[0052] [Formula 1] Where, X n is the mass fraction (mass % / 100) of the monomer n used in the synthesis of component (A) relative to the total amount of monomers used in the synthesis of component (A), Tg n is the glass transition temperature (K Kelvin) of the homopolymer of this monomer n.

[0053] For example, Tg n Reference may be made to the values ​​described in the second edition of "Polymer Handbook", J. Wiley & Sons, New York (1975). For example, according to the handbook, the Tg of polystyrene is 373K, the Tg of polybutyl methacrylate is 293K, the Tg of polybutyl acrylate is 219K, the Tg of poly-2-hydroxyethyl methacrylate is 328K, and the Tg of polymethacrylic acid is 458K.

[0054] The weight average molecular weight (hereinafter also referred to as "Mw") of the component (A) is preferably 1,000 or more, more preferably 3,000 or more, particularly preferably 4,000 or more, and is preferably 100,000 or less, more preferably 50,000 or less, particularly preferably 30,000 or less, from the viewpoint of being able to easily form a coating film that is less prone to cracking, has excellent folding resistance, and has excellent weather resistance and chemical resistance.

[0055] In the present invention, Mw is a weight average molecular weight of standard polystyrene equivalent measured by GPC (gel permeation chromatography) method, and can be specifically measured by the method described in the following examples.

[0056] The amine value of the solid component of the component (A) is preferably 1 mgKOH / g or more, more preferably 5 mgKOH / g or more, particularly preferably 10 mgKOH / g or more, and is preferably 50 mgKOH / g or less, more preferably 40 mgKOH / g or less.

[0057] By using the component (A) having an amine value within the above range, a composition having better drying properties and / or curing properties can be easily obtained, and a coating film having excellent weather resistance and chemical resistance can be easily formed.

[0058] Furthermore, from the viewpoint of further reducing the viscosity of the composition of the present invention, the amine value of the solid component of the above-mentioned component (A) is preferably 1 mgKOH / g or more, more preferably 5 mgKOH / g or more, and is preferably 30 mgKOH / g or less, more preferably 20 mgKOH / g or less.

[0059] The above-mentioned amine value can be measured in accordance with JIS K 7237:1995.

[0060] The content (solid content) of component (A) in 100% by mass of the non-volatile components of the above-mentioned composition 1 is preferably 5% by mass or more, more preferably 10% by mass or more, particularly preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 45% by mass or less, particularly preferably 40% by mass or less.

[0061] When the content of component (A) is within the above range, a coating film that is less prone to cracking and has excellent balance in weather resistance, curing performance, adhesion to epoxy resin primer coating film, and adhesion between old coating film and new coating film can be easily formed.

[0062] The non-volatile component of the composition of the present invention (composition 1 or composition 2) refers to the mass percentage of the coating film (heating residual component) after the composition of the present invention is fully reacted and cured (heated) or the coating film (heating residual component) itself. The above non-volatile component can be calculated by measuring 1±0.1g of the composition of the present invention (for example, the composition after the main agent and the curing agent are mixed) into a flat-bottomed culture dish, spreading it evenly with a metal wire of known mass, drying it at a temperature of 23°C for 24 hours, and heating it at a heating temperature of 108°C for 3 hours (under normal pressure) and measuring the mass of the heating residual component and the metal wire. It should be noted that the non-volatile component is equivalent to the total amount of the solid component (components other than the solvent) of the raw material components used in the composition of the present invention.

[0063] <Carboxyl group-containing resin (B)> Component (B) is a resin other than component (AB), that is, a resin not containing a tertiary amino group, and is not particularly limited as long as it has at least one carboxyl group in one molecule. Component (B) is a resin other than component (E) described below.

[0064] The component (B) used in the present invention may be one kind or two or more kinds.

[0065] Component (B) specifically includes, for example, carboxyl-containing acrylic resins (B1), carboxyl-containing fluororesins (B2), carboxyl-containing polyester resins, and carboxyl-containing alkyd resins. Among them, carboxyl-containing acrylic resins (B1) and carboxyl-containing fluororesins (B2) are preferred from the viewpoint of being able to easily form a coating film having a good balance between weather resistance and chemical resistance, and carboxyl-containing acrylic resins (B1) are more preferred from the viewpoint of easy availability.

[0066] From the perspective of being able to easily form a coating film that has a good balance between coating hardness and bending resistance and is less likely to cause stickiness and cracks, the Tg of component (B) is preferably -5°C or higher, more preferably 0°C or higher, and is preferably 50°C or lower, more preferably 40°C or lower.

[0067] The Tg can be measured and calculated in the same manner as described in the component (A) section.

[0068] From the viewpoint of being able to easily form a coating film that is less prone to cracking, has excellent folding resistance, and has excellent weather resistance and chemical resistance, the Mw of component (B) is preferably 1,000 or more, more preferably 3,000 or more, and particularly preferably 4,000 or more, and is preferably 100,000 or less, more preferably 50,000 or less, and particularly preferably 30,000 or less.

[0069] The acid value of the solid component of the component (B) is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, and is preferably 70 mgKOH / g or less, more preferably 60 mgKOH / g or less.

[0070] By using the component (B) having an acid value within the above range, a composition having better drying properties and / or curing properties can be easily obtained, and a coating film having excellent weather resistance and chemical resistance can be easily formed.

[0071] The acid value can be measured in accordance with JIS K 0070:1992.

[0072] The content (solid content) of component (B) in 100% by mass of the non-volatile components of the above-mentioned composition 1 is preferably 5% by mass or more, more preferably 10% by mass or more, particularly preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 45% by mass or less, particularly preferably 40% by mass or less.

[0073] When the content of component (B) is within the above range, a coating film excellent in adhesion to the epoxy resin-based primer coating film and adhesion between the old coating film and the new coating film can be easily formed.

[0074] [Carboxyl group-containing acrylic resin (B1)] Component (B1) can be synthesized by (co)polymerization using, for example, an unsaturated monomer containing a carboxyl group by a known method. Specifically, it can be synthesized by free radical (co)polymerization using an unsaturated monomer containing a carboxyl group and, if necessary, an unsaturated monomer not containing a carboxyl group. Among them, as at least one of the monomers used in the (co)polymerization, a compound having a (meth)acryloyl group is used.

[0075] Alternatively, component (B1) may be synthesized by radical (co)polymerizing unsaturated monomers not containing a carboxyl group (wherein at least one of the monomers is a compound having a (meth)acryloyl group) and then modifying the monomers so that the resulting resin has a carboxyl group.

[0076] Component (B) can be synthesized by a conventional method, specifically, by reacting monomers in the presence of a polymerization initiator and a solvent.

[0077] Examples of the unsaturated monomer containing a carboxyl group include (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, allyloxypropionic acid, 2-(meth)acryloylethylsuccinic acid, 3-butenoic acid, 4-pentenoic acid, 2-hexenoic acid, 3-hexenoic acid, 5-hexenoic acid, 2-heptenoic acid, 3-heptenoic acid, 3-octenoic acid, 2-nonenoic acid, 3-nonenoic acid, 9-decenoic acid, 10-undecenoic acid, and 2-tridecenoic acid. Among these, (meth)acrylic acid is preferably used.

[0078] The carboxyl group-containing unsaturated monomer may be used alone or in combination of two or more.

[0079] From the viewpoint of being able to easily obtain a composition with excellent drying properties and being able to easily form a coating film with excellent chemical resistance, water resistance and coating film hardness, the amount of the above-mentioned unsaturated monomer containing a carboxyl group is preferably 1% by mass or more, more preferably 2% by mass or more, and is preferably 30% by mass or less, more preferably 20% by mass or less, relative to 100% by mass of the total amount of the monomers used when synthesizing component (B1).

[0080] Examples of the unsaturated monomer not containing a carboxyl group include the same monomers as exemplified as the monomer (a-2) above, etc. Among them, methyl (meth)acrylate, n-butyl (meth)acrylate, and styrene are preferably used.

[0081] The unsaturated monomer not containing a carboxyl group may be used alone or in combination of two or more.

[0082] From the viewpoint of being able to easily obtain a composition having excellent drying and / or curing properties, and being able to easily form a coating film having excellent chemical resistance, water resistance, and coating film hardness, the amount of the unsaturated monomer not containing a carboxyl group used is preferably 70% by mass or more, more preferably 80% by mass or more, and is preferably 99% by mass or less, more preferably 98% by mass or less, based on 100% by mass of the total amount of the monomers used when synthesizing component (B1).

[0083] [Carboxyl group-containing fluororesin (B2)] Component (B2) can be synthesized by (co)polymerization of, for example, fluoroolefins and carboxyl-containing monomers by a known method, or may be a commercially available product. For example, when synthesizing component (B2), fluoroolefins (b1) and carboxyl-containing unsaturated carboxylic acids (b2) can be copolymerized, and then, if necessary, further copolymerized with vinyl ethers (b3) and / or vinyl esters (b4).

[0084] Examples of the fluoroolefins (b1) include Fluorinated vinyls such as CClF=CF2, CHCl=CF2, CCl2=CF2, CClF=CClF, CHF=CCl2, CH2=CClF, CCl2=CClF, CF2=CF2, CF2=CH2; CF2ClCF=CF2, CF3CCl=CF2, CF3CF=CFCl, CF2ClCCl=CF2, CF2ClCF=CFCl, CFCl2CF=CF2, CF3CCl=CClF, CF3CCl=CCl2, CClF2CF=CCl2, CCl3CF=CF2, CF2ClCCl=CCl 2. CFCl2CCl=CCl2, CF3CF=CHCl, CClF2CF=CHCl, CH3CCl=CHCl, CHF2CCl=CCl2, CF2ClCH=CCl2, CF2ClCCl=CHCl, CCl3CF=CHCl, CHBrCF=CCl2, CF2=CFOCF3 and other fluoropropylenes; Fluoroolefins having more than 4 carbon atoms such as CF3CCl=CFCF3, CF2=CFCF2CClF2, CF3CF2CF=CCl2, CF2=CFOC3F7, etc.

[0085] Among them, perhalogenated olefins such as CF2=CF2 and CClF=CF2 in which hydrogen atoms of the olefins are all replaced by halogens are preferred.

[0086] As the fluoroolefins (b1), one kind may be used, or two or more kinds may be used.

[0087] Examples of the carboxyl group-containing unsaturated carboxylic acids (b2) include (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, allyloxypropionic acid, 2-(meth)acryloylethylsuccinic acid, 3-butenoic acid, 4-pentenoic acid, 2-hexenoic acid, 3-hexenoic acid, 5-hexenoic acid, 2-heptenoic acid, 3-heptenoic acid, 3-octenoic acid, 2-nonenoic acid, 3-nonenoic acid, 9-decenoic acid, 10-undecenoic acid, and 2-tridecenoic acid.

[0088] As the carboxyl group-containing unsaturated carboxylic acid (b2), one kind may be used, or two or more kinds may be used.

[0089] Examples of the vinyl ethers (b3) include Aliphatic alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, octyl vinyl ether, neopentyl vinyl ether, tert-butyl vinyl ether, etc. Cyclohexyl vinyl ether and other alicyclic alkyl vinyl ethers; Aromatic vinyl ethers such as phenyl vinyl ether, benzyl vinyl ether, naphthyl vinyl ether; Isopropenyl ethers such as methyl isopropenyl ether, ethyl isopropenyl ether, propyl isopropenyl ether, butyl isopropenyl ether and cyclohexyl isopropenyl ether; Hydroxyalkyl vinyl ethers such as 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 9-hydroxynonyl vinyl ether, 1-hydroxymethyl-4-vinyloxymethylcyclohexane, and 3-chloro-2-hydroxypropyl vinyl ether; Hydroxyalkyl isopropenyl ethers such as 2-hydroxyethyl isopropenyl ether, 3-hydroxypropyl isopropenyl ether, 4-hydroxybutyl isopropenyl ether, 9-hydroxynonyl isopropenyl ether, 1-hydroxymethyl-4-isopropenyloxymethylcyclohexane, and 3-hydroxy-2-chloropropyl isopropenyl ether.

[0090] The vinyl ethers (b3) may be used alone or in combination of two or more.

[0091] Examples of the vinyl esters (b4) include CH2=CHOCOR 3 The compound represented by (R 3 : an aliphatic, alicyclic or aromatic monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent).

[0092] As the R 3 The substituent in may include a hydroxyl group, a halogen atom, etc., but preferably it is not a hydroxyl group.

[0093] The vinyl esters (b4) may be used alone or in combination of two or more.

[0094] Preferred examples of the vinyl esters (b4) include: Fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl valerate, vinyl octanoate, and vinyl stearate; Aromatic carboxylic acid vinyl esters such as vinyl benzoate and vinyl p-tert-butylbenzoate.

[0095] Furthermore, when synthesizing the component (B2), other monomers than the above-mentioned (b1) to (b4) may also be used.

[0096] Examples of the other monomers include Olefins such as ethylene, propylene, and isobutylene; Halogenated olefins such as vinyl chloride and vinylidene chloride; Allyl carboxylates such as allyl formate, allyl butyrate, allyl benzoate, and allyl cyclohexanecarboxylate; Allyl ethers such as allyl ethyl ether and allyl phenyl ether.

[0097] Component (B2) can be synthesized by the method described in, for example, Japanese Patent Application Laid-Open No. 7-238116 and Japanese Patent Application Laid-Open No. 8-157537.

[0098] <Acrylic resin containing tertiary amino group and carboxyl group (AB)> Component (AB) is not particularly limited as long as it contains at least one tertiary amino group and one carboxyl group per molecule.

[0099] The component (AB) used in the composition of the present invention may be one kind or two or more kinds.

[0100] Component (AB) can be synthesized by (co)polymerization using, for example, an unsaturated monomer containing a tertiary amino group and an unsaturated monomer containing a carboxyl group by a known method. Specifically, it can be synthesized by free radical (co)polymerization of an unsaturated monomer containing a tertiary amino group, an unsaturated monomer containing a carboxyl group, and an unsaturated monomer containing neither a tertiary amino group nor a carboxyl group as required. At least one of the monomers used in the (co)polymerization is a compound having a (meth)acryloyl group.

[0101] Alternatively, component (AB) may be synthesized by free radical (co)polymerizing unsaturated monomers not containing a tertiary amino group and a carboxyl group (wherein at least one of the monomers is a compound having a (meth)acryloyl group) and then modifying the monomers so that the resulting resin has a tertiary amino group and a carboxyl group.

[0102] Component (AB) can be synthesized by a conventional method, and specifically, can be synthesized by reacting monomers in the presence of a polymerization initiator and a solvent.

[0103] Examples of the tertiary amino group-containing unsaturated monomer include the same monomers as exemplified as the monomer (a-1) described in the above component (A). The tertiary amino group-containing unsaturated monomer may be used alone or in combination of two or more.

[0104] Examples of the above-mentioned unsaturated monomer containing a carboxyl group include the same monomers as those exemplified as the unsaturated monomer containing a carboxyl group in the above-mentioned component (B). The unsaturated monomer containing a carboxyl group may be used alone or in combination of two or more.

[0105] From the perspectives of being able to easily obtain a composition with excellent drying properties and being able to easily form a coating film with excellent chemical resistance, water resistance, and coating film hardness, the total amount of the tertiary amino group-containing unsaturated monomer and the carboxyl group-containing unsaturated monomer used is preferably 1% by mass or more, more preferably 2% by mass or more, and is preferably 30% by mass or less, more preferably 25% by mass or less, relative to 100% by mass of the total amount of the monomers used when synthesizing component (AB).

[0106] Examples of the unsaturated monomer containing neither a tertiary amino group nor a carboxyl group include the same monomers as exemplified as the monomer (a-2) described in the above component (A).

[0107] The unsaturated monomer containing neither a tertiary amino group nor a carboxyl group may be used alone or in combination of two or more.

[0108] From the viewpoint of being able to easily obtain a composition having excellent drying and / or curing properties, and being able to easily form a coating film having excellent chemical resistance, water resistance, and coating film hardness, the amount of the unsaturated monomer containing neither a tertiary amino group nor a carboxyl group used is preferably 70% by mass or more, more preferably 75% by mass or more, and is preferably 99% by mass or less, more preferably 98% by mass or less, relative to 100% by mass of the total amount of the monomers used when synthesizing the component (AB).

[0109] From the perspective of being able to easily form a coating film that has a good balance between coating hardness and bending resistance and is less likely to cause stickiness and cracks, the Tg of component (AB) is preferably -5°C or higher, more preferably 0°C or higher, and is preferably 50°C or lower, more preferably 40°C or lower.

[0110] The Tg can be measured and calculated in the same manner as described in the component (A) section.

[0111] From the viewpoint of being able to easily form a coating film that is less prone to cracking, has excellent bending resistance, and has excellent weather resistance and chemical resistance, the Mw of component (AB) is preferably 1,000 or more, more preferably 1,500 or more, and particularly preferably 2,000 or more, and is preferably 100,000 or less, more preferably 50,000 or less, and particularly preferably 30,000 or less.

[0112] The amine value of the solid component of the component (AB) is preferably 1 mgKOH / g or more, more preferably 5 mgKOH / g or more, particularly preferably 10 mgKOH / g or more, and is preferably 50 mgKOH / g or less, more preferably 40 mgKOH / g or less.

[0113] By using the component (AB) having an amine value within the above range, a composition having better drying properties and / or curing properties can be easily obtained, and a coating film having excellent weather resistance and chemical resistance can be easily formed.

[0114] Furthermore, from the viewpoint of further reducing the viscosity of the composition of the present invention, the amine value of the solid component in the above component (AB) is preferably 1 mgKOH / g or more, more preferably 5 mgKOH / g or more, and is preferably 30 mgKOH / g or less, more preferably 20 mgKOH / g or less.

[0115] The above-mentioned amine value can be measured in accordance with JIS K 7237:1995.

[0116] The acid value of the solid component of the component (AB) is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, and is preferably 70 mgKOH / g or less, more preferably 60 mgKOH / g or less.

[0117] By using the component (AB) having an acid value within the above range, a composition having better drying properties and / or curing properties can be easily obtained, and a coating film having excellent weather resistance and chemical resistance can be easily formed.

[0118] The acid value can be measured in accordance with JIS K 0070:1992.

[0119] The content (solid content) of the component (AB) in 100% by mass of the non-volatile components of the above-mentioned composition 2 is preferably 10% by mass or more, more preferably 20% by mass or more, particularly preferably 30% by mass or more, and is preferably 75% by mass or less, more preferably 70% by mass or less, particularly preferably 60% by mass or less.

[0120] When the content of component (AB) is within the above range, a coating film excellent in adhesion to the epoxy resin-based primer coating film and adhesion between an old coating film and a new coating film can be easily formed.

[0121] <Epoxy-containing silane compound (C)> There is no particular limitation on component (C), as long as each molecule has at least one epoxy group, and it may be any of a monomer, an oligomer and a polymer. The component (C) used in the composition of the present invention may be one or more than one.

[0122] It should be noted that since component (C) has an epoxy group, a coating film that can achieve the above-mentioned effect can be formed. On the other hand, when only a compound without an epoxy group is used, the above-mentioned desired effect cannot be achieved.

[0123] As component (C), compounds having epoxy groups and alkoxy groups are preferred from the viewpoint of being able to easily form a coating film having better weather resistance, etc., more preferably, a silane coupling agent containing an alkoxy group having one epoxy group per molecule, and particularly preferably, a compound represented by the following formula. The compound represented by the following formula has the function of chemically bonding the pigment described later to the coating film forming components such as components (A), (B), (AB) and (E), and has the effect of improving the adhesion to the substrate on which the coating film is formed. [n is 0 or 1, X represents an epoxy group, a group in which a part of the hydrocarbon group has been replaced by an epoxy group, or a group in which a part of the hydrocarbon group has been replaced by an ether bond or the like and a part of the hydrocarbon group has been replaced by an epoxy group, R is an alkyl group, and Y represents an alkoxy group such as a methoxy group or an ethoxy group.] Examples of the silane compound represented by the above formula include γ-glycidyloxypropylmethyldimethoxysilane, γ-glycidyloxypropylmethyldiethoxysilane and other γ-glycidyloxyalkyldialkoxysilanes; γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane and other γ-glycidyloxyalkyltrialkoxysilanes; 3,4-epoxycyclohexylethylmethyldimethoxysilane and other 3,4-epoxycyclohexylalkylalkyldialkoxysilanes; 3,4-epoxycyclohexylethyltrimethoxysilane, 3,4-epoxycyclohexylethyltriethoxysilane, 3,4-epoxycyclohexylethyltripropoxysilane and other 3,4-epoxycyclohexylalkyltrialkoxysilanes; and these silane compounds may be oligomers or polymers obtained by dehydration condensation.

[0124] Examples of the oligomer include compounds having a number average molecular weight (Mn) of preferably 200 or more, more preferably 300 or more, and preferably 2,000 or less, more preferably 1,000 or less.

[0125] Examples of the polymer include compounds having an Mw of preferably 3,000 or more, more preferably 5,000 or more, and preferably 50,000 or less, more preferably 30,000 or less.

[0126] The content (solid content) of component (C) in 100% by mass of the non-volatile components of the composition of the present invention is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, particularly preferably 2% by mass or more, and is preferably 30% by mass or less, more preferably 20% by mass or less, particularly preferably 15% by mass or less.

[0127] When the content of component (C) is within the above range, a composition having good coating workability and excellent drying properties that can be cured at room temperature can be easily obtained, and a coating film having excellent weather resistance can be easily formed.

[0128] <Epoxy resin (D)> Component (D) is component (C) and an epoxy resin other than an epoxy group-containing acrylic resin. Examples of the epoxy group-containing acrylic resin include the following component (F).

[0129] By using component (D) together with components (A) to (C), or together with components (AB) and (C), it is possible to significantly improve the adhesion to the epoxy resin primer coating film and the adhesion between the old coating film and the new coating film while maintaining the good weather resistance of the existing composition. In particular, by using component (C) and component (D) together, it is possible to easily form a coating film that is excellent in both weather resistance and curing performance.

[0130] The component (D) used in the composition of the present invention may be one kind or two or more kinds.

[0131] It is preferred that component (D) contains no Si atom and has no structure derived from a (meth)acryloyl group.

[0132] As component (D), preferably, there are polymers or oligomers containing two or more epoxy groups in the molecule, and polymers or oligomers generated by the ring-opening reaction of the epoxy groups, etc. As component (D), there can be mentioned bisphenol type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, and cresol novolac type epoxy resins.

[0133] Among them, from the perspective of being able to easily form a coating film with excellent adhesion to the epoxy resin primer coating film and between the old coating film and the new coating film, bisphenol-type epoxy resins are preferred, bisphenol-A epoxy resins and bisphenol-F epoxy resins are more preferred, and bisphenol-A epoxy resins are particularly preferred.

[0134] Component (D) is preferably a compound other than aliphatic polyol polyglycidyl ethers (eg, glycerol polyglycidyl ether, sorbitol polyglycidyl ether), vinyl polymers having epoxy groups in side chains, and polyether polyol polyglycidyl ethers (eg, polyethylene glycol glycidyl ether).

[0135] Examples of the bisphenol A epoxy resin include polycondensates of bisphenol A diglycidyl ethers.

[0136] Examples of the bisphenol A type diglycidyl ethers include bisphenol A diglycidyl ether, bisphenol A polyoxypropylene diglycidyl ether, and bisphenol A oxyethylene diglycidyl ether.

[0137] The epoxy equivalent of component (D) is preferably 150 to 1000, more preferably 150 to 800, and particularly preferably 180 to 700, from the viewpoints of achieving high curing due to reduced viscosity of the composition of the present invention and easily forming a coating film having excellent hardness after drying the composition of the present invention.

[0138] It should be noted that the epoxy resin equivalent is calculated based on JIS K 7236:2001.

[0139] Component (D) is preferably an epoxy resin that is liquid or semisolid at room temperature, from the viewpoint of being able to easily form a coating film having excellent adhesion to an epoxy resin-based primer coating film and between an old coating film and a new coating film.

[0140] Component (D) may be a product synthesized by a conventionally known method or may be a commercially available product.

[0141] Examples of commercially available products that are liquid at room temperature (temperature of 15 to 25° C., the same below) include “E-028” (manufactured by Ohtake Meishin Chemical Co., Ltd., bisphenol A type epoxy resin, epoxy equivalent of 180 to 190, solid content of 100 mass %), “jER 807” (manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin, epoxy equivalent of 160 to 175, solid content of 100 mass %), and “E-028-90X” (manufactured by Ohtake Meishin Chemical Co., Ltd., bisphenol A type epoxy resin xylene solution (828 type epoxy resin solution, epoxy equivalent of 200 to 210, solid content of 90 mass %).

[0142] Examples of commercially available products that are semi-solid at room temperature include "jER 834" (manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin, epoxy equivalent 230 to 270, solid content 100% by mass), "E-834-85X" (manufactured by Ohtake Meishin Chemical Co., Ltd., bisphenol A type epoxy resin xylene solution (834 type epoxy resin solution, epoxy equivalent 270 to 320, solid content 85% by mass), and the like.

[0143] Commercially available products that are solid at room temperature include "jER 1001" (manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin, epoxy equivalent of 450 to 500, solid content of 100 mass %), "E-001-75" (manufactured by Ohtake Meishin Chemical Co., Ltd., bisphenol A type epoxy resin xylene solution (1001 type epoxy resin solution), epoxy equivalent of 600 to 660, solid content of 75 mass %), etc.

[0144] The content of component (D) in 100% by mass of the non-volatile components of the composition of the present invention (solid content) is preferably 1% by mass or more, more preferably 1.4% by mass or more, particularly preferably 2% by mass or more, and is preferably 30% by mass or less, more preferably 20% by mass or less, particularly preferably 15% by mass or less.

[0145] When the content of component (D) is within the above range, a coating film having not only excellent weather resistance but also excellent adhesion to an epoxy resin-based primer coating film and adhesion between an old coating film and a new coating film can be easily formed.

[0146] The mass ratio of the content of component (C) to the content of component (D) (content of component (C):content of component (D)) is preferably 1:7 to 7:1, more preferably 1:7 to 1.5:1, and even more preferably 1:3 to 1.2:1.

[0147] When the content ratio of component (C) to component (D) is within the above range, a coating film can be easily formed which not only maintains good weather resistance but also has excellent adhesion to the epoxy resin primer coating film and adhesion between the old coating film and the new coating film.

[0148] [Other components] The composition of the present invention may contain other components in addition to the above-mentioned components (A) to (D) as needed, within the range not impairing the effects of the present invention, such as silicone resin (E), epoxy-containing acrylic resin (F), pigment, dispersant, defoaming agent, leveling agent, thickener, anti-sagging agent (anti-settling agent), curing accelerator, light stabilizer, light absorber (e.g., ultraviolet absorber), and organic solvent.

[0149] Each of these other components may be used alone or in combination of two or more.

[0150] The other components mentioned above may be mixed with the main agent or with the curing agent.

[0151] The composition of the present invention preferably does not substantially contain a compound having an isocyanate group from the viewpoint of being able to form a coating composition that imposes less load on the human body and the environment during coating.

[0152] When a fluororesin is used, a compound having an isocyanate group is generally used to produce a room temperature curable coating composition. However, according to the composition of the present invention, even when component (B2) is used, a room temperature curable coating composition that does not contain a compound having an isocyanate group can be formed.

[0153] It should be noted that substantially containing no compound having an isocyanate group means that the content of the compound having an isocyanate group is 0.001% by mass or less in 100% by mass of the non-volatile components of the composition of the present invention.

[0154] [Silicone resin (E)] The component (E) is a resin having a siloxane bond and is not particularly limited as long as it does not contain an epoxy group. It may be linear or branched.

[0155] When the composition of the present invention contains the component (E), a coating film having more excellent weather resistance, coating film hardness and chemical resistance can be easily formed.

[0156] In addition, component (E) may also have a reactive group other than an epoxy group (e.g., an amino group, a carboxyl group). When a component having a reactive group is used as component (E), by reacting the reactive groups with each other or reacting the reactive groups with the reactive groups in components (A), (B), (C), (D) and / or (F), a high molecular weight component or a three-dimensional crosslinked structure can be formed, thereby improving the weather resistance and hardness of the coating film. Component (E) having such a reactive group can be combined with a curing agent.

[0157] Component (E) is preferably a resin represented by the following formula (I). [In formula (I), R 1 Each is independently an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a group in which the hydrogen atoms of these groups are substituted with an amino group and / or a carboxyl group, or a reactive group other than an epoxy group. 2 Each is independently an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 8 carbon atoms, a group in which the hydrogen atoms of these groups are substituted with amino groups and / or carboxyl groups, or a reactive group other than a hydrogen atom or epoxy group. In addition, n represents the number of repeating units.] As the above R 1 and R 2 Examples of the alkyl group having 1 to 8 carbon atoms include methyl, ethyl, propyl, butyl and pentyl.

[0158] As the above R 1 and R 2 The aryl group having 6 to 8 carbon atoms may be a group having a substituent such as an alkyl group on the aromatic ring, and examples thereof include phenyl, methylphenyl, and dimethylphenyl.

[0159] As the above R 1 Examples of the alkoxy group having 1 to 8 carbon atoms include a methoxy group, an ethoxy group, a propoxy group and a phenoxy group.

[0160] The above R 1 Preferably, methyl, ethyl, propyl or phenyl, and the above R 2 Preferred is a methyl group, an ethyl group, a phenyl group or a hydrogen atom.

[0161] As the above R 1 and R 2 Examples of the reactive groups other than the epoxy group include an amino group and a carboxyl group.

[0162] From the viewpoint of easily forming a coating film having a good balance between weather resistance and flexibility (bending resistance), the Mw of component (E) is preferably 400 or more, more preferably 500 or more, and is preferably 10,000 or less, more preferably 7,000 or less.

[0163] The number n of repeating units is preferably selected so that the Mw of component (E) is within the above range.

[0164] Since the viscosity of the component (E) having an Mw exceeding the upper limit of the above range is high, in order to reduce the viscosity of the composition containing the component (E), it is often necessary to dilute it with an organic solvent described below, etc., in consideration of operability. As a result, the solvent content in the composition of the present invention will increase, and the VOC (Volatile Organic Compounds) in the composition of the present invention may not be reduced.

[0165] Component (E) is preferably a resin having weather resistance and water repellency such as methyl silicone resin and methylphenyl silicone resin, and more preferably contains one or more structural units selected from the following dimethylsiloxane unit (a1), diphenylsiloxane unit (a2), methylphenylsiloxane unit (a3), monomethylsiloxane unit (a4), monopropylsiloxane unit (a5) and monophenylsiloxane unit (a6). [In formulas (a1) to (a6), the "-" in Si-O- that is bonded to O but not to Si represents a covalent bond, and Si-O- does not necessarily represent Si-O-CH3.] Component (E) can be synthesized by a known synthesis method or can be a commercial product. Examples of the commercial product include "Dow Corning 3074 intermediate", "Dow Corning 3055" (manufactured by DuPont Toray Specialty Materials Co., Ltd.), "SILRES HP2000" (manufactured by Asahi Kasei Wacker Silicones Co., Ltd.), and "Wacker SilicateTES 40WN" (manufactured by Asahi Kasei Wacker Silicones Co., Ltd.).

[0166] When the composition of the present invention contains component (E), the content (solid content) of component (E) in 100% by mass of the non-volatile components of the composition of the present invention is preferably 0.5% by mass or more, more preferably 1% by mass or more, particularly preferably 1.3% by mass or more, and is preferably 45% by mass or less, more preferably 30% by mass or less, particularly preferably 20% by mass or less, from the perspective of being able to easily form a coating film having both excellent weather resistance and flexibility (bending resistance).

[0167] [Epoxy-containing acrylic resin (F)] The component (F) is not particularly limited as long as it is a resin other than the components (A) to (E) and is an acrylic resin having at least one epoxy group per molecule.

[0168] When the composition of the present invention contains component (F), a coating film having better flexibility (bending resistance) and glossiness can be easily formed.

[0169] When the composition of the present invention is a two-component composition comprising a main agent of components (A) and (B) or a main agent of the above-mentioned component (AB) and a curing agent of components (C) and (D), component (F) is preferably blended into the curing agent.

[0170] Component (F) can be synthesized by (co)polymerization using, for example, an unsaturated monomer containing an epoxy group by a known method. Specifically, it can be synthesized by free radical (co)polymerization of an unsaturated monomer containing an epoxy group and, if necessary, an unsaturated monomer not containing an epoxy group. Among them, as at least one of the monomers used in the (co)polymerization, a compound having a (meth)acryloyl group is used.

[0171] Alternatively, component (F) may be synthesized by free radical (co)polymerization of unsaturated monomers not containing epoxy groups (wherein at least one of the monomers is a compound having a (meth)acryloyl group) followed by modification, etc., so that the final resin has epoxy groups.

[0172] Component (F) can be synthesized by a conventional method.

[0173] Examples of the epoxy group-containing unsaturated monomer include glycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylpropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and allyl glycidyl ether. Among them, glycidyl (meth)acrylate is preferably used.

[0174] The epoxy group-containing unsaturated monomer may be used alone or in combination of two or more.

[0175] From the viewpoint of being able to easily form a coating film having excellent chemical resistance, water resistance and coating film hardness, the amount of the epoxy group-containing unsaturated monomer used is preferably 1% by mass or more, more preferably 2% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, based on 100% by mass of the total amount of the monomers used when synthesizing component (F).

[0176] Examples of the unsaturated monomer not containing an epoxy group include the same monomers as exemplified as the monomer (a-2) described in the above component (A).

[0177] Among them, methyl (meth)acrylate, n-butyl (meth)acrylate, and styrene are preferably used.

[0178] The unsaturated monomer not containing an epoxy group may be used alone or in combination of two or more.

[0179] Component (F) can be synthesized by the method described in International Publication No. 2014 / 175246, for example.

[0180] From the viewpoint of being able to easily form a coating film having a good balance between flexibility (bending resistance) and coating film hardness, the Mw of component (F) is preferably 1,000 or more, more preferably 3,000 or more, and is preferably 50,000 or less, more preferably 30,000 or less.

[0181] When the composition of the present invention contains component (F), the content (solid content) of component (F) in 100% by mass of the non-volatile components of the composition of the present invention is preferably 1% by mass or more, more preferably 2% by mass or more, and is preferably 25% by mass or less, more preferably 20% by mass or less, from the perspective of being able to easily form a coating film having better flexibility (bending resistance) and glossiness.

[0182] [pigment] Examples of the pigment include extender pigments and coloring pigments, and any of the pigments may be organic or inorganic.

[0183] When the composition of the present invention is a multi-component composition containing a main agent and a curing agent, the pigment may be blended with either the main agent or the curing agent, or may be blended with both, or may be blended with a third-party agent other than the two. When the composition of the present invention is a two-component composition containing a main agent of components (A) and (B) or a main agent containing the above-mentioned component (AB) and a curing agent containing components (C) and (D), it is preferred that the pigment be blended with the main agent.

[0184] When the composition of the present invention contains a pigment, the content of the pigment in 100% by mass of the non-volatile components of the composition of the present invention is preferably 20% by mass or more, more preferably 25% by mass or more, and is preferably 60% by mass or less, more preferably 50% by mass or less, from the perspective of being able to easily form a coating film that is not only excellent in weather resistance and flexibility (bending resistance) but also has a stress relaxation effect.

[0185] The extender pigment is not particularly limited, and a conventionally known pigment can be used, but it is a pigment other than the coloring pigment described below.

[0186] Examples of the extender pigment include talc, mica, barium sulfate (including precipitated barium sulfate and panned barium sulfate), (potassium) feldspar, kaolin, alumina white, clay, magnesium carbonate, barium carbonate, calcium carbonate, dolomite, silica, glass slag, and plastic slag. Talc, silica, (precipitated) barium sulfate, (potassium) feldspar, and mica are particularly preferred.

[0187] When the composition of the present invention contains an extender pigment, the content of the extender pigment in 100% by mass of the non-volatile components of the composition of the present invention is preferably 5% by mass or more, more preferably 10% by mass or more, and is preferably 50% by mass or less, more preferably 45% by mass or less, from the perspective of being able to easily form a coating film excellent in flexibility (bending resistance).

[0188] The coloring pigment is not particularly limited, and conventionally known pigments can be used.

[0189] As the coloring pigment, conventionally known inorganic pigments such as carbon black, titanium dioxide (titanium white), iron oxide (red iron), yellow iron oxide, ultramarine, aluminum flakes, flaky iron oxide, stainless steel flakes, and organic pigments such as cyanine blue and cyanine green can be used. Titanium white, carbon black, and red iron are particularly preferred.

[0190] When the composition of the present invention contains a coloring pigment, the content of the coloring pigment in 100% by mass of the non-volatile components of the composition of the present invention is preferably 0.1% by mass or more, more preferably 1% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less.

[0191] [Anti-sagging agent (anti-settling agent)] As the anti-sagging agent, organic clay waxes such as stearates, lecithin salts, and alkyl sulfonates of Al, Ca, and Zn, polyethylene wax, amide wax, hydrogenated castor oil wax, synthetic micropowder silica, oxidized polyethylene wax, and other conventionally known anti-sagging agents (anti-settling agents) can be used, among which amide wax, synthetic micropowder silica, oxidized polyethylene wax, and organic clay wax are preferred.

[0192] When the composition of the present invention contains an anti-sagging agent (anti-settling agent), the content of the anti-sagging agent (anti-settling agent) in 100% by mass of the non-volatile components of the composition of the present invention is preferably 0.3 to 10% by mass.

[0193] [Light stabilizer] The light stabilizer is not particularly limited, and examples thereof include conventionally known light stabilizers such as hindered amine-based light stabilizers.

[0194] Examples of the hindered amine light stabilizer include bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, methyl(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 2,4-bis[N-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine, and bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl) sebacate.

[0195] As the light stabilizer, a commercial item can be used, and examples of such commercial items include "TINUVIN 292", "TINUVIN 144" and "TINUVIN 123" (all manufactured by BASF).

[0196] When the composition of the present invention contains a light stabilizer, the content of the light stabilizer in 100% by mass of the non-volatile components of the composition of the present invention is preferably 0.1 to 5% by mass.

[0197] [Organic solvents] The organic solvent is not particularly limited, and examples thereof include aromatic hydrocarbon solvents such as toluene, xylene, "Ipsol 100" (manufactured by Idemitsu Kosan Co., Ltd.), "Swasol 1000" (manufactured by Maruzen Petrochemical Co., Ltd.), "Solvesso 100", "Solvesso 150" (manufactured by ExxonMobil Corporation), and "LAWS" (manufactured by Shell), ketone solvents such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK), ester solvents such as butyl acetate, alcohol solvents such as isopropyl alcohol and benzyl alcohol, and aliphatic hydrocarbon solvents such as mineral spirits, n-hexane, n-octane, 2,2,2-trimethylpentane, isooctane, n-nonane, cyclohexane, and methylcyclohexane.

[0198] When the composition of the present invention contains an organic solvent, the content of the organic solvent in 100 mass % of the composition of the present invention is preferably 5 mass % or more, more preferably 10 mass % or more, and is preferably 50 mass % or less, more preferably 40 mass % or less.

[0199] <Method for preparing the composition of the present invention> The composition of the present invention, the main agent, the curing agent, etc. can be prepared by mixing (kneading) the components for preparing them. When mixing (kneading), the components can be added and mixed at once or in multiple times. In addition, the mixing can be performed while heating or cooling, etc., depending on the season, environment, etc.

[0200] When the composition of the present invention is a two or more component type composition containing a main agent and a curing agent, it can be prepared by mixing (kneading) the main agent, the curing agent, and other agents (eg, a third agent) used as needed.

[0201] When performing the above-mentioned mixing (kneading), conventionally known mixing equipment, dispersing equipment, stirring equipment, etc. can be used. Examples of the mixing equipment, dispersing equipment, stirring equipment include a mixing / dispersing mill, a mortar mixer, a roll mill, a paint shaker, and a homogenizer.

[0202] <<Coating film and coated articles with coating film>> A coating film according to one embodiment of the present invention (hereinafter also referred to as "the coating film of the present invention") is formed using the above-mentioned composition of the present invention, and a coated article with a coating film according to one embodiment of the present invention (hereinafter also referred to as "the coated article with the coating film of the present invention") is a laminate having the coating film of the present invention and a coated article. Such a coated article with the coating film of the present invention can be produced by, for example, a method including the following steps [1] and [2].

[0203] Step [1]: a step of applying the composition of the present invention to a coating object; Step [2]: A step of drying the applied composition of the present invention to form a coating film.

[0204] The composition of the present invention can be directly coated on a substrate made of steel (iron, steel, iron alloy, carbon steel, low carbon steel, alloy steel, etc.), non-ferrous metal (aluminum, copper, brass, galvanized, zinc sprayed, etc.), stainless steel (SUS304, SUS410, etc.), but is usually coated on a substrate with a conventionally known anti-corrosion coating, anti-rust coating, and other primer coatings.

[0205] From the perspective of better expressing the effects of the present invention, the coated article is preferably a substrate having an epoxy resin primer coating film (particularly an epoxy resin primer anticorrosive coating film).

[0206] That is, the coated article with the coating film of the present invention is preferably a substrate with a laminated coating film comprising a substrate, an epoxy resin primer coating film, and the coating film of the present invention in this order. Such a substrate with a laminated coating film can be produced, for example, by a method comprising the following steps [1'] and [2'].

[0207] Step [1′]: a step of applying the composition of the present invention to a substrate having an epoxy resin primer coating film formed thereon (preferably, a step of applying the following epoxy coating to the substrate, drying (curing) the applied epoxy coating to form an epoxy resin primer coating film, and applying the composition of the present invention to the formed epoxy resin primer coating film).

[0208] Step [2']: a step of drying the applied composition of the present invention to form a coating film.

[0209] As the substrate of the above material, for example, land-based components such as ships, bridges, storage tanks, integrated equipment, and iron towers; port facilities, offshore buoys, pipelines, FPSO (floating offshore oil and gas production and storage shipping equipment), FLNG (floating offshore natural gas liquefaction equipment), oil drilling rigs, oil storage bases, large buoys, offshore wind power generation equipment, tidal power generation equipment and other sea-based components (large) steel components, etc. Among them, the substrate that requires weather resistance is preferred, and ships are more preferred.

[0210] The dry film thickness of the coating film of the present invention is not particularly limited and can be appropriately selected according to the desired application. From the perspective of obtaining a coating film having sufficient weather resistance, it is usually 15 μm or more, preferably 25 μm or more, and usually 300 μm or less, preferably 200 μm or less.

[0211] The thickness of the epoxy resin primer coating film is not particularly limited, but is usually 50 to 500 μm, preferably 100 to 350 μm.

[0212] Examples of coating methods in the above steps [1] and [1′] include, but are not particularly limited to, spray coating such as airless spray coating and air spray coating, coating using a brush, roller, spatula, or flat shovel, and other conventionally known methods. Among them, spray coating is preferred because it can easily coat a large-area substrate such as the above-mentioned member.

[0213] When such coating is performed, it is preferred to perform coating so that the dry film thickness of the obtained coating film is within the above-mentioned range.

[0214] During the coating process of the composition of the present invention, the viscosity of the coating composition can be adjusted to an appropriate value as required. It should be noted that the description of the present invention other than this section is related to the composition of the present invention and the epoxy coating before dilution.

[0215] It should be noted that before applying the composition of the present invention and the epoxy coating described below, the coated part (substrate) may be subjected to surface treatment as required. Specifically, rust, grease, moisture, dust, etc. that have been generated or adhered to the surface of the coated part (substrate) to be coated may be cleaned and removed, or a sealant, adhesive, primer, etc. may be pre-coated according to the purpose and material of the coated part (substrate).

[0216] That is, the above-mentioned articles to be coated and substrates include articles to be coated and substrates to which a sealant, adhesive, primer, etc. are applied.

[0217] In order to improve the adhesion between the obtained coating film and the substrate, it is preferably treated according to the following methods (for example, sandblasting (ISO8501-1 Sa21 / 2), degreasing to remove oil and dust). In addition, for the purpose of primary rust prevention, the substrate may also be coated with a maintenance primer.

[0218] When applying the composition of the present invention or the following epoxy coating, a coating having a desired film thickness may be formed by a single application (single-layer application) or by two or more applications (two or more application).

[0219] It should be noted that the method of coating twice or more is a method in which, for example, after the coated object has undergone steps [1] and [2] to form a dry coating film at least once, the dried coating film obtained through these steps is further subjected to the above steps [1] and [2] to form a dry coating film.

[0220] It should be noted that in the above step [1′], although the coating depends on the desired application and the conditions at the coating site, it is also possible to form an epoxy resin primer coating film, then leave a certain period of time (interval) and then apply the composition of the present invention.

[0221] The drying conditions in the above steps [2] and [2′] are not particularly limited and can be appropriately set according to the method for forming the coating film, the type of substrate, the application, the coating environment, etc. The drying temperature is usually 5 to 35°C, more preferably 10 to 30°C, when drying at room temperature. It should be noted that although forced drying (for example, 30 to 90°C) can be performed by heating, blowing air, etc. as needed, drying and curing are usually performed under natural conditions.

[0222] The drying time varies depending on the method for drying the coating film, but in the case of drying at room temperature, it is usually 1 to 7 days, preferably 1 to 3 days.

[0223] <Epoxy resin primer coating> The epoxy resin primer coating film is a coating film formed of an epoxy resin coating composition (also referred to as "epoxy coating"). The epoxy coating is not particularly limited, and a conventionally known epoxy resin coating composition can be used. However, from the perspective of the anticorrosive performance of the epoxy resin primer coating film formed by the epoxy coating and the adhesion to the substrate, it is preferred that the epoxy coating contains the following epoxy resin (p) and epoxy resin curing agent (q).

[0224] <Epoxy resin (p)> The epoxy resin (p) is not particularly limited, but examples thereof include polymers or oligomers having two or more epoxy groups in the molecule, and polymers or oligomers obtained by ring-opening of the epoxy groups thereof, etc. Examples of such epoxy resins include glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, bisphenol epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, dicyclopentadiene epoxy resins, aliphatic epoxy resins, alicyclic epoxy resins, and fatty acid-modified epoxy resins.

[0225] The epoxy resin (p) may be used alone or in combination of two or more.

[0226] Among them, from the perspective of being able to easily form a coating film with excellent corrosion resistance and adhesion to the substrate, bisphenol epoxy resin is preferred, more preferably one or more selected from bisphenol A type, bisphenol AD ​​type and bisphenol F type epoxy resins, and bisphenol A type epoxy resin is particularly preferred.

[0227] The weight average molecular weight and epoxy equivalent of the epoxy resin (p) are not always determined by the coating and curing conditions (e.g., natural drying coating or baking coating) of the resulting epoxy coating, but the weight average molecular weight measured by the GPC method is usually 350 to 20,000, and the epoxy equivalent is usually 150 to 1,000.

[0228] From the viewpoint of being able to easily form a coating film with excellent corrosion resistance, the content of the epoxy resin (p) is generally 10 to 60% by mass, preferably 20 to 50% by mass, relative to 100% by mass of the epoxy coating including the solvent, and the content of the epoxy resin (p) is generally 10 to 70% by mass, preferably 20 to 60% by mass, relative to 100% by mass of the solid component of the epoxy coating.

[0229] <Curing agent for epoxy resin (q)> The epoxy resin curing agent (q) is not particularly limited, but specific examples thereof include amine curing agents and acid anhydride curing agents, and amine curing agents are preferred.

[0230] Examples of the amine curing agent include aliphatic amine curing agents, alicyclic amine curing agents, aromatic amine curing agents, heterocyclic amine curing agents, other amine curing agents such as polyether diamine, and modified forms of these amine curing agents (e.g., polyamide, polyamide amine [polyamide resin], amine adducts with epoxy compounds, Mannich compounds [e.g., Mannich-modified polyamide amine], Michael adducts, ketimines, aldimines, and phenalkamines).

[0231] As a specific example of the amine curing agent, for example, the curing agent described in Japanese Patent Application No. 2018-44162 can be mentioned.

[0232] The curing agent (q) may be used alone or in combination of two or more.

[0233] The activated hydrogen equivalent of the amine curing agent is preferably 50 to 1,000, more preferably 80 to 400, from the viewpoint of being able to easily form an epoxy resin primer coating film having excellent anticorrosive properties.

[0234] When an amine curing agent is used as the curing agent (q), the equivalent ratio (amount of amine curing agent used / active hydrogen equivalent) / (amount of epoxy resin used / epoxy equivalent) is preferably 0.20 to 0.9, more preferably 0.25 to 0.75.

[0235] Examples of the acid anhydride curing agent include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, hexachloroendomethylenetetrahydrophthalic anhydride, and methyl-3,6-endomethylenetetrahydrophthalic anhydride.

[0236] <Additives> In addition to the epoxy resin (p) and the curing agent (q), the epoxy coating may contain additives such as a curing accelerator, a pigment, a sagging agent (anti-settling agent), a defoaming agent, and a solvent. From the perspectives of price and adhesion to the substrate of the resulting coating film, it is preferred to contain a pigment.

[0237] As the additive, the same components as those described in the above-mentioned other components of the composition of the present invention can be used.

[0238] Each of these additives may be used alone or in combination of two or more.

[0239] The volume fraction (VS) of the solid component of the epoxy coating measured according to ISO 3233 is preferably 50 to 100%, more preferably 55 to 90%, and particularly preferably 60 to 85%.

[0240] Example An embodiment of the present invention is further described in detail below with reference to an example, but the present invention is not limited thereto.

[0241] [Production Example 1] <Synthesis of Tertiary Amino Group-Containing Acrylic Resin> 41.5 parts by mass of xylene as a solvent was added to the reaction apparatus, and the temperature was raised to 110°C under a nitrogen flow. Then, while the temperature of the reaction apparatus was maintained at 110°C, 100 parts by mass of a mixed solution of monomer components (38.0 parts by mass of styrene, 37.0 parts by mass of n-butyl methacrylate, 15.0 parts by mass of n-butyl acrylate, and 10.0 parts by mass of dimethylaminoethyl methacrylate) and 4.2 parts by mass of 2,2′-azobis(2-methylbutyronitrile) as an initiator were dripped into the reaction apparatus over 3 hours. After the dripping, the temperature was kept at the same temperature for 2 hours to synthesize an acrylic resin containing a tertiary amino group.

[0242] [Production Example 2] <Synthesis of Carboxyl Group-Containing Acrylic Resin> 29.4 parts by mass of xylene and 12.6 parts by mass of n-butanol as solvents were added to the reaction apparatus, and the temperature was raised to 115° C. under a nitrogen flow. Then, while the temperature of the reaction apparatus was maintained at 115° C., 100 parts by mass of a mixed solution of monomer components (38.0 parts by mass of styrene, 5.0 parts by mass of methyl methacrylate, 50.0 parts by mass of n-butyl acrylate, and 7.0 parts by mass of methacrylic acid) and a mixed solution of 3.0 parts by mass of tert-butyl peroxy(2-ethylhexanoate) and 0.8 parts by mass of tert-butyl peroxybenzoate as initiators were added dropwise to the reaction apparatus over 4 hours. After the addition, the temperature was maintained at the same temperature for 4 hours to synthesize a carboxyl group-containing acrylic resin.

[0243] [Production Example 3] <Synthesis of Epoxy-containing Acrylic Resin> 42.0 parts by mass of xylene as a solvent was added to the reaction apparatus, and the temperature was raised to 120°C under a nitrogen flow. Then, while the temperature of the reaction apparatus was maintained at 120°C, 100 parts by mass of a mixed solution of monomer components (35.0 parts by mass of styrene, 20.5 parts by mass of methyl methacrylate, 29.5 parts by mass of n-butyl acrylate, and 15.0 parts by mass of glycidyl methacrylate) and 5.0 parts by mass of 2,2′-azobis(2-methylbutyronitrile) as an initiator were added dropwise to the reaction apparatus over 3 hours. Then, 0.5 parts by mass of tert-butyl peroxy(2-ethylhexanoate) was added to the reaction vessel, and the temperature was maintained at the same temperature for 2 hours to synthesize an epoxy group-containing acrylic resin.

[0244] <Weight average molecular weight (Mw)> The standard polystyrene equivalent Mw of the raw materials used in the following examples and comparative examples was measured by GPC under the following conditions. The measurement conditions are as follows.

[0245] GPC conditions Equipment: "Alliance 2695" (manufactured by Waters) Chromatographic columns: One "TSKgel SuperH4000" and two "TSKgel SuperH2000" connected (both manufactured by Tosoh Corporation, inner diameter 6mm x length 15cm) Eluent: Tetrahydrofuran 99 mass% (BHT stabilized) Flow rate: 0.6ml / min Detector: "RI-104" (made by Shodex) Column thermostat temperature: 40°C Standard material: Standard polystyrene Sample preparation method: The raw materials used in the following examples and comparative examples were weighed into a sample tube, and tetrahydrofuran was added to dilute the solution to about 100 times.

[0246] <Glass transition temperature (Tg)> The glass transition temperatures (Tg) of the raw materials used in the following examples and comparative examples were calculated using the above-mentioned Fox equation.

[0247] [Examples 1 to 18 and Comparative Examples 1 to 4] The components constituting the main agent described in Tables 1 and 2 were added to a plastic container according to the amounts (values) described in Tables 1 and 2, stirred using a high-speed disperser, and then an appropriate amount of glass beads were added, and dispersed using a paint shaker for 2 hours. The glass beads were then removed to prepare the main agent.

[0248] Furthermore, the respective components constituting the curing agent described in Tables 1 and 2 were added to a container in the amounts (numerical values) described in Tables 1 and 2, and sufficiently dispersed using a high-speed disperser to prepare a curing agent.

[0249] When coating, the prepared main agent and curing agent are mixed to prepare a coating composition.

[0250] The numerical values ​​of each component in Table 1 and Table 2 represent parts by mass. It should be noted that the description of each component described in Table 1 and Table 2 is shown in Table 3.

[0251] <Adhesion to primer coating> A grit-blasted steel plate with a size of 150 mm × 70 mm × 1.6 mm (thickness) was prepared.

[0252] Banno 1500 (manufactured by China Paint Co., Ltd.) was applied to the surface of the steel plate by air spraying to a dry film thickness of 200 μm, and dried at 23° C. for 1 day to form a primer coating film.

[0253] The steel plate with the primer coating film formed was exposed outdoors for 60 days. The attached matter on the surface of the primer coating film after outdoor exposure was removed with a dry brush, and each coating composition of the embodiment and the comparative example was applied to the primer coating film with the attached matter removed with an applicator (gap: 0.3 mm), and dried at a temperature of 23°C for 7 days to prepare a steel plate with a topcoat coating film (test plate).

[0254] The prepared test plate was exposed outdoors for 6 months, and the coating on the test plate after outdoor exposure was cross-cut (cell size: 2mm×2mm, total number of cells: 25 cells) until it reached the primer coating film, and the adhesion between the primer coating film and the topcoat coating film was evaluated according to JIS K 5600-5-6:1999 "Adhesion (cross-cut method)". The evaluation was based on the ratio of the total area of ​​the peeling part where the topcoat coating film peeled off from the primer coating film to the total area of ​​the above 25 cells (peeling area %). The smaller the ratio of the peeling part area, the better the adhesion to the primer coating film. The results are shown in Tables 1 and 2.

[0255] <Weather resistance> An aluminum plate treated with Alodine having a size of 150 mm × 70 mm × 0.8 mm (thickness) was prepared. The coating compositions of the embodiments and comparative examples were applied to the surface of the aluminum plate using an applicator (gap: 0.3 mm), and dried at 23° C. for 7 days to prepare a weather resistance test plate.

[0256] The weather resistance test plate was subjected to a 1500-hour weather resistance test using a super xenon lamp weather resistance tester SX75 (manufactured by SUGA Testing Instruments Co., Ltd.).

[0257] Then, the reflectance of light incident at an angle of 60° from the vertical direction of the coating surface after the weathering test (60° gloss) was measured using a gloss meter (model: BYK-Gardner), and the gloss retention (%) relative to the 60° gloss value of the coating before the weathering test was calculated. Based on the gloss retention value, the weathering resistance of the coating was evaluated. The higher the gloss retention, the better the weathering resistance of the coating. The results are shown in Tables 1 and 2.

[0258] <Recoatability on old coating film> A grit-blasted steel plate with a size of 150 mm × 70 mm × 1.6 mm (thickness) was prepared.

[0259] Banno 1500 (manufactured by China Paint Co., Ltd.) was applied to the surface of the steel plate by air spraying to a dry film thickness of 200 μm, and dried at 23° C. for 1 day to form a primer coating film.

[0260] Each coating composition of the examples and comparative examples was applied on the primer coating film by air spraying to a dry film thickness of 50 μm, and dried at 23° C. for 1 day to form a top coating film.

[0261] The steel plate with the topcoat film formed thereon was exposed outdoors for one year. The surface of the topcoat film after outdoor exposure was washed with tap water and dried at room temperature to prepare a steel plate with an old coating film.

[0262] Next, a coating composition similar to that used to form the old coating film was applied to the old coating film of the steel plate with the old coating film using an applicator (gap: 0.3 mm), and the mixture was dried at 23° C. for 7 days to prepare a steel plate with a new coating film (test plate).

[0263] The prepared test plate was exposed outdoors for 6 months, and the coating on the test plate after outdoor exposure was cross-cut (cell size: 2mm×2mm, total number of cells: 25 cells) until it reached the primer coating, and the adhesion between the old coating and the new coating was evaluated according to JIS K 5600-5-6:1999 "Adhesion (cross-cut method)". The evaluation was based on the ratio of the total area of ​​the peeled-off portion of the new coating from the old coating to the total area of ​​the above 25 cells (peeled area %). The smaller the ratio of the peeled-off portion, the better the recoatability on the old coating. The results are shown in Tables 1 and 2.

[0264] <Curing Properties> A grit-blasted steel plate with a size of 150 mm × 70 mm × 1.6 mm (thickness) was prepared.

[0265] Banno 1500 (manufactured by China Paint Co., Ltd.) was applied to the surface of the steel plate by air spraying to a dry film thickness of 200 μm, and dried at 23° C. for 1 day to form a primer coating film.

[0266] Each coating composition of the examples and comparative examples was applied on the primer coating film by air spraying to a dry film thickness of 50 μm, and dried at 23° C. for 7 days to form a topcoat coating film.

[0267] Then, the hardness of the topcoat coating film was measured in accordance with JIS K5600-5-4:1999 "Scratch hardness (pencil method)" and the hardness of the topcoat coating film was evaluated.

[0268] [Table 1] [Table 2] [Table 3]

Claims

1. A coating composition, characterized in that comprising an acrylic resin (A) containing a tertiary amino group and a resin (B) containing a carboxyl group, or comprising an acrylic resin (AB) containing a tertiary amino group and a carboxyl group, The present invention also includes an epoxy resin (D) other than an epoxy group-containing silane compound (C) and an epoxy group-containing acrylic resin.

2. The coating composition according to claim 1, characterized in that As a mass ratio of the content of the epoxy group-containing silane compound (C) to the content of the epoxy resin (D), the content of the silane compound (C):the content of the epoxy resin (D) is 1:7 to 7:

1.

3. The coating composition according to claim 1 or 2, characterized in that Also contains silicone resin (E).

4. The coating composition according to any one of claims 1 to 3, characterized in that The coating composition is coated on the epoxy resin primer coating film.

5. A coating film, characterized in that: The coating film is formed from the coating composition according to any one of claims 1 to 4.

6. A substrate with a laminated coating, characterized in that: The substrate with a laminated coating film comprises a substrate, an epoxy resin primer coating film, and the coating film according to claim 5 in this order.

7. A method for producing a substrate with a laminated coating film, characterized in that: The method comprises the following steps [1] and [2], [1] A step of applying the coating composition according to any one of claims 1 to 4 onto a substrate having an epoxy resin primer coating film formed thereon, [2] A step of drying the applied coating composition to form a coating film.

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