JP6953167B2 - Paint composition and coating film forming method - Google Patents

Description

A coating composition and a coating film for forming a coating film having excellent storage stability under high humidity conditions and having impact resistance, bending resistance, water resistance and chemical resistance. Regarding the forming method.

In the painting of industrial products such as parts such as blades for automobile bodies, construction machine bodies, wind power generators, etc., in recent years, from the viewpoint of energy saving, reduction of environmental load, and cost competition, the life of paints and coating films has been extended. And stable quality is required.

A hydroxyl group / isocyanate group cross-linked paint that cures a main agent containing a hydroxyl group-containing resin and a curing agent containing a polyisocyanate compound has been widely used in various coating fields, and the process can be shortened by short-time curing or the like. For the purpose, various studies using the above-mentioned cross-linking paint have been made.

The applicant applies to a coating material containing a hydroxyl group-containing acrylic resin and a polyisocyanate compound containing a specific secondary hydroxyl group-containing polymerizable unsaturated monomer as a copolymerization component, and an organic metal catalyst composed of a specific range of metal compounds and amidine compounds. The composition has been disclosed (Patent Document 1). However, the coating composition described in Cited Document 1 is insufficient in storage stability, curability when coated under high humidity conditions, and impact resistance and flexibility of the obtained coating film.

Further, the applicant is a coating composition containing a polyol, a polyisocyanate compound and a curing catalyst, wherein the polyol has a polyol having a constituent unit derived from a fatty acid having 8 or more carbon atoms and a curing catalyst is at least one imidazole ring. Disclosed a coating composition using an imidazole compound having the above (Patent Document 2). The coating composition described in Cited Document 2 may have insufficient curability, and the balance between storage stability and curability, as well as water resistance and chemical resistance will be insufficient only by adjusting the amount of catalyst. There was a case.

International Publication WO2013 / 047208 Pamphlet International Publication WO2015 / 111709 Pamphlet

The present invention has been made in view of the above circumstances, and an object of the present invention is that the coating composition is extremely excellent in storage stability, and even after storage, there is little dependence on the coating environment such as humidity and excellent curability. It is an object of the present invention to provide a coating composition in which the obtained coating film is excellent in impact resistance, bending resistance, water resistance and chemical resistance, and a method for forming a coating film of the coating composition.

Under such circumstances, as a result of diligent research, the present inventors have found that in a coating composition containing a polyol and a polyisocyanate compound, the polyol has a constituent unit derived from a fatty acid having 8 or more carbon atoms as a part of its components. It has been found that the above-mentioned problems can be solved by containing a bismuth compound as a curing catalyst and containing a specific amount of a carboxylic acid having 8 or more carbon atoms.

The present invention provides a coating composition and a coating film forming method shown in the following sections:
Item 1. A coating composition containing a polyol (A), a polyisocyanate compound (B), a curing catalyst (C), and a carboxylic acid (D) having 8 or more carbon atoms, wherein the polyol (A) has 8 or more carbon atoms. It contains a polyol (A1) having a constituent unit derived from a fatty acid, the component (C) contains a (C1) bismuth compound, and the content of the component (D) is the solid content of the polyol (A). A coating composition characterized by being in the range of 0.1 to 10 parts by mass with reference to 100 parts by mass.

Item 2. Item 2. The coating composition according to Item 1, wherein the component (A1) is a polyol (A1') having a constituent unit derived from a fatty acid having 8 or more carbon atoms and having a primary hydroxyl group.

Item 3. Item 1 or 2 which contains at least one polyol (A2) selected from the group consisting of polycaprolactone diol, polycaprolactone triol, polycaprolactone tetraol, polycarbonate diol, and polyacrylate polyol as the polyol (A). The coating composition according to.

Item 4. Any one of Items 1 to 3 in which the content of the component (C1) of the component (C) is in the range of 0.005 to 4 parts by mass based on 100 parts by mass of the solid content of the polyol (A). The paint composition according to the section.

Item 5. Item 6. The coating composition according to any one of Items 1 to 4, further containing an N-substituted imidazole compound (C2) as the component (C).

Item 6. Item 5. The coating composition according to Item 5, wherein the content of (C2) in the component (C) is in the range of 0.005 to 8 parts by mass based on 100 parts by mass of the solid content of the polyol (A).

Item 7. Item 6. The coating composition according to any one of Items 1 to 6, wherein the component (D) is at least one selected from neodecanoic acid, lauric acid and tridecanoic acid.

Item 8. The coating composition according to any one of Items 1 to 7, further comprising hydrophobic silica particles (E) having an average primary particle size of 5 to 30 μm.

Item 9. Item 4. The coating composition according to any one of Items 1 to 8, further comprising at least one antifoaming agent (F) selected from acrylic, vinyl ether, and acetylene glycol-based polymers.

Item 10. A coating film forming method for forming a coating film by coating an object to be coated with the coating composition according to any one of Items 1 to 9.

By using the coating composition of the present invention, the coating composition can be stored for a long period of time, and a coating film having excellent impact resistance, bending resistance, water resistance and chemical resistance can be formed even in the coating composition after storage. .. In addition, it has excellent curability even when it is painted in a high humidity atmosphere or when the base contains moisture, the generation of foaming is suppressed, the foam marks of the coating film are reduced, and the appearance of the coating film is excellent and the coating film is stable. Physical characteristics can be obtained.

≪Paint composition≫
The present invention is a coating composition containing a polyol (A), a polyisocyanate compound (B), a curing catalyst (C), and a carboxylic acid (D) having 8 or more carbon atoms, wherein the component (A) is carbon. The polyol (A1) having a constituent unit derived from a fatty acid of several 8 or more is contained, the component (C) contains the (C1) bismuth compound, and the content of the component (D) is the polyol (A). The coating composition is characterized by having a solid content in the range of 0.1 to 10 parts by mass based on 100 parts by mass of the solid content.

<< polyol (A) >>
In the present invention, the polyol (A) contains, at least as a part thereof, a polyol (A1) having a constituent unit derived from a fatty acid having 8 or more carbon atoms.

<Polycarbonate (A1) having a constituent unit derived from a fatty acid having 8 or more carbon atoms>
In the present invention, the "polyol having a fatty acid-derived structural unit having 8 or more carbon atoms (A1)" is a polyol having a fatty acid-derived structural unit, and at least among the fatty acid-derived structural units constituting the polyol. One has 8 or more carbon atoms (preferably 10 or more). The upper limit of the number of carbon atoms in a fatty acid having 8 or more carbon atoms is not particularly limited, but can be appropriately set from, for example, 28 or less carbon atoms, preferably 25 or less carbon atoms, and more preferably 20 or less carbon atoms.

The fatty acid of the constituent unit is a compound represented by the general formula CnHmCOOH [where n represents an integer of 7 to 27 and m represents an integer of 14 to 54], and the polyol (A1) used in the present invention is , The compound having at least one fatty acid having a total number of carbons n + 1 (carbons of a carbonyl group) of the above general formula of 8 or more as a constituent unit.

Specific examples of fatty acids having 8 or more carbon atoms include ricinoleic acid (also known as ricinoleic acid, molecular formula C ₁₈ H ₃₂ O ₃ , a secondary hydroxyl group at the 12-position, and one carbon-carbon double bond at the 9-position. Oleic acid derivative), ricineraidic acid (steric isomer of ricinoleic acid) and other hydroxyl group-containing unsaturated fatty acids, octenoic acid (8 carbon atoms, unsaturated group number 1), nonenic acid (carbon number 9 and unsaturated group number 1) , Caproleic acid (10 carbons, 1 unsaturated group), Touhaku acid (10 carbons, 1 unsaturated group), Undecilenic acid (11 carbons, 1 unsaturated group), Linderic acid (12 carbons, 1 unsaturated group) 1), tridecenoic acid (13 carbons, 1 unsaturated group), myristoleic acid (14 carbons, 1 unsaturated group), palmitrenic acid (16 carbons, 1 unsaturated group), sabienoic acid (also known as hexedecenoic acid, 15 carbons, 1 unsaturated group), oleic acid (18 carbons, 1 unsaturated group), elaidic acid (18 carbons, 1 unsaturated group), baxenoic acid (18 carbons, 1 unsaturated group), gadrain Acid (20 carbons, 1 unsaturated group), Eicosenoic acid (20 carbons, 1 unsaturated group), Elcaic acid (22 carbons, 1 unsaturated group), Nerbonic acid (24 carbons, 1 unsaturated group) , Linolic acid (18 carbons, 2 unsaturated groups), Eikosadienic acid (20 carbons, 2 unsaturated groups), Docosadienoic acid (22 carbons, 2 unsaturated groups), Linolenic acid (18 carbons, 2 unsaturated groups) 3), pinolenic acid (18 carbons, 3 unsaturated groups), eleostearic acid (18 carbons, 3 unsaturated groups), meadic acid (20 carbons, 3 unsaturated groups), ecosatrienic acid (carbon) Number 20, unsaturated groups 3), stearidonic acid (18 carbons, 4 unsaturated groups), arachidonic acid (20 carbons, 4 unsaturated groups), eikosatetraenoic acid (20 carbons, 4 unsaturated groups) , Adrenic acid (22 carbons, 4 unsaturated groups) and other unsaturated fatty acids that do not have a hydroxyl group. Saturated fatty acids that do not have a carbon-carbon double bond in the molecule include capric acid (also known as octanoic acid, 8 carbon atoms), pelargonic acid (also known as nonanoic acid, 9 carbon atoms), and capric acid (also known as capric acid). : Decanoic acid, 10 carbon atoms), Undecanoic acid (also known as undecic acid, 11 carbon atoms), Lauric acid (also known as dodecic acid, 12 carbon atoms), Tridecanoic acid (13 carbon atoms), Myristic acid (also known as tetradecanoic acid) , 14 carbon atoms), pentadecanoic acid (15 carbon atoms), partiminic acid (also known as isomilystinic acid or hexadecanoic acid, 16 carbon atoms), isopalmitic acid (also known as 2-hexyldecanoic acid, 16 carbon atoms), isostearic acid (also known as isomyric acid or hexadecanoic acid, 16 carbon atoms), isostearic acid (also known as 2-hexyldecanoic acid, 16 carbon atoms). Saturated fatty acids without hydroxyl groups such as 18) carbon atoms, 10-hydroxystearic acid (18 carbon atoms, 1 hydroxyl group), 12-hydroxystearic acid (18 carbon atoms, 1 hydroxyl group), celebronic acid (24 carbon atoms) , The number of hydroxyl groups 1) and the like, and examples thereof include hydroxyl group-containing saturated fatty acids. These fatty acids may be used alone or in combination of two or more.

As the fatty acid, for example, a substance containing a carboxylic acid as a functional group, which is obtained by hydrolyzing what exists as a glyceride in fats and oils extracted from natural animals and plants and purifying the fatty acid with or without separation, is appropriately used. can do. Alternatively, it may be a fatty acid obtained by chemically synthesizing petroleum or the like as a raw material.

Examples of the fats and oils include coconut oil, palm oil, flaxseed oil, sunflower oil, soybean oil, sesame oil, sunflower oil, olive oil, camellia oil, rapeseed oil, palm kernel oil and the like. The fat and oil is usually a glyceride of a mixed fatty acid containing the fatty acid in an amount of, for example, 75% or more, preferably 80% or more. Therefore, since glycerin is contained in the fat and oil skeleton, it is inevitably one component of the polyhydric alcohol. As the carbon number of the fatty acid, it is preferable to contain a fatty acid having 8 to 28 carbon atoms, particularly 10 to 20 carbon atoms as a main component (preferably 80% or more). These fat and oil raw materials may be used alone or in combination of two or more.

As the component (A1), for example,
(A1-1) Esterized product of hydroxyl acid-containing fatty acid having 8 or more carbon atoms and polyhydric alcohol (A1-2) Multimer of hydroxyl group-containing unsaturated fatty acid having 8 or more carbon atoms (A1-3) Non-substituted fatty acid having 8 or more carbon atoms A polyol (A1-4) obtained by reducing a multimer of a saturated fatty acid, an unsaturated fatty acid having 8 or more carbon atoms (a1-4-1) and / or an esterified product of an unsaturated fatty acid having 8 or more carbon atoms and a polyhydric alcohol (a1). Examples thereof include a polyol obtained by modifying -4-2) with a fatty acid.

Examples of the component (A1-1) include those listed as examples of hydroxyl group-containing unsaturated fatty acids having 8 or more carbon atoms and / or hydroxyl group-containing saturated fatty acids constituting the component (A1) and esters of polyhydric alcohols. ..

Examples of the polyhydric alcohol include glycerin, ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, trimethylolpropane, pentaerythritol, sorbitol and the like. These polyhydric alcohols may be used alone or in combination of two or more.

Examples of those containing the component (A1-1) include castor oil, hydrogenated castor oil and the like. Castile oil is a vegetable oil made from castor seeds and is known to be a glyceride of unsaturated fatty acids such as ricinoleic acid and oleic acid and saturated fatty acids such as palmitic acid. Here, since ricinoleic acid is a hydroxyl group-containing unsaturated fatty acid having 8 or more carbon atoms, castor oil as a component (A) or a hydrogenated castor oil which is a modified product thereof is blended with the component (A1-). 1) will be included. These components (A1-1) can be used alone or in combination of two or more.

The hydroxyl value of the component (A1-1) is in the range of 150 mgKOH / g or more and less than 200 mgKOH / g.

As the component (A1-2), a large amount of dimers, trimmers, tetramers, etc. copolymerized by unsaturated bonds of those listed as examples of hydroxyl group-containing unsaturated fatty acids having 8 or more carbon atoms constituting the component (A1). Body polyols are mentioned, with dimers preferred. These components (A1-2) can be used alone or in combination of two or more.

The hydroxyl value of the above component (A1-2) is in the range of 200 to 720 mgKOH / g.

As the component (A1-3), copolymerization is carried out by an unsaturated bond possessed by those listed as examples of a hydroxyl group-containing unsaturated fatty acid having 8 or more carbon atoms and / or an unsaturated fatty acid having no hydroxyl group constituting the component (A1). Examples thereof include multimeric polyols obtained by reducing a multimer such as a saturated dimer, trimmer, or tetramer from a carboxylic acid to an alcohol using a reducing agent or the like. As the multimer, dimer is preferable. As the reducing agent, conventionally known ones can be used, and examples thereof include lithium borohydride, sodium borohydride, and lithium aluminum borohydride.

The hydroxyl value of the above component (A1-3) is in the range of 200 to 220 mgKOH / g.

Further, as the component (A1-3), a commercially available product can be used, and examples thereof include PRIPOL2033 manufactured by CRODA.

These components (A1-3) can be used alone or in combination of two or more.

Finally, (A1-4) an unsaturated fatty acid having 8 or more carbon atoms (a1-4-1) and / or an esterified product of an unsaturated fatty acid having 8 or more carbon atoms and a polyhydric alcohol (a1-4-2). A hydroxyl group-modified polyol will be described.

Of the above-mentioned unsaturated fatty acid (a1-4-1) having 8 or more carbon atoms in the component (A1-4) and / or an esterified product (a1-4-2) of an unsaturated fatty acid having 8 or more carbon atoms and a polyhydric alcohol. The hydroxyl modification can be carried out by a method known per se.

Specifically, for example, the unsaturated group in the above components (a1-4-1) and / or (a1-4-2) is epoxidized with a peroxide, and then monovalent or multivalent with the epoxide produced. Examples thereof include a method of reacting with alcohol.

Examples of the unsaturated fatty acid (a1-4-1) having 8 or more carbon atoms as a raw material of the component (A1-4) include a hydroxyl group-containing unsaturated fatty acid having 8 or more carbon atoms constituting the component (A1) and / or Those listed as examples of unsaturated fatty acids having no hydroxyl group can be publicly used.

As the polyhydric alcohol used as a raw material for the component (A1-4), those listed in the section of the component (A1-1) can be preferably used. These polyhydric alcohols can be used alone or in combination of two or more.

Further, as the esterified product (a1-4-2) of the unsaturated fatty acid having 8 or more carbon atoms and the polyhydric alcohol, which is the raw material of the component (A1-4), for example, the above-mentioned unsaturated fatty acid having 8 or more carbon atoms And the above-mentioned esterified product of polyhydric alcohol, more specifically, the esterified product of unsaturated fatty acid having 8 to 28 carbon atoms, preferably 10 to 20 carbon atoms and polyvalent alcohol, and the like. Specifically, a glyceride of an unsaturated fatty acid having 8 or more carbon atoms, preferably 8 to 28 carbon atoms, and more preferably 10 to 20 carbon atoms can be preferably used.

The glyceride of the unsaturated fatty acid having 8 or more carbon atoms is contained in, for example, fats and oils. Therefore, when the component (a1-4-2) is used as the raw material of the component (A1-4), an oil or fat containing a glyceride of an unsaturated fatty acid having 8 or more carbon atoms can be used.

As the fat and oil containing the glyceride of the unsaturated fatty acid having 8 or more carbon atoms, for example, soybean oil, castor oil, palm oil, rapeseed oil and the like can be preferably used.

Of the above-mentioned unsaturated fatty acid (a1-4-1) having 8 or more carbon atoms in the component (A1-4) and / or an esterified product (a1-4-2) of an unsaturated fatty acid having 8 or more carbon atoms and a polyhydric alcohol. The hydroxyl modification can be carried out by a method known per se. Specifically, for example, the unsaturated group in the above components (a1-4-1) and / or (a1-4-2) is epoxidized with a peroxide, and then monovalent or multivalent with the epoxide produced. Examples thereof include a method of reacting with alcohol.

Examples of the peroxide for epoxidizing the unsaturated group in the above components (a1-4-1) and / or (a1-4-2) include peracetic acid and hydrogen peroxide.

Examples of the monohydric alcohol for hydroxylation modification of the epoxide include linear primary alcohols such as methanol, ethanol and propanol; secondary alcohols such as isopropanol; unsaturated group-containing alcohols such as allyl alcohol; isobutanol, Branched alcohols such as neopentyl alcohol; cyclic alcohols such as cyclohexanol and benzyl alcohol; ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol monopropyl ether; diethylene glycol mono such as diethylene glycol monomethyl ether Alkyl ethers; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ethers; dipropylene glycol monoalkyl ethers such as dipropylene glycol monomethyl ethers and the like. These monohydric alcohols can be used alone or in combination of two or more. As the polyhydric alcohol for hydroxyl group modification of the epoxide, those listed in the section of the component (A1-1) can be preferably used. These polyhydric alcohols can be used alone or in combination of two or more.

Further, as the above component (A1-4), a commercially available product can be used. Examples of commercially available products include BASF's Sovermol 750, Sovermol 760, Sovermol 805, Sovermol 815, Sovermol 819, Sovermol 1095, Ito Oil Chemicals' URIC H-81, URIC H73-X, and URIC H-854. ..

These components (A1-4) can be used alone or in combination of two or more.

Further, these components (A1-1), component (A1-2), component (A1-3) and component (A1-4) can be used alone or in combination of two or more.

The hydroxyl value of the above component (A1-4) is preferably in the range of 200 to 720 mgKOH / g.

The component (A1) has a constituent unit derived from a fatty acid having 8 or more carbon atoms from the viewpoint of pot life (pot life), storage stability, curability, impact resistance, and water resistance balance. Moreover, it is preferable to use a polyol (A1') having a primary hydroxyl group.

When the component (A1') is used, the ratio of the primary and secondary hydroxyl groups to the total amount of hydroxyl groups present in the molecule of the polyol is the balance between pot life and curability and the impact resistance of the coating film. From the point of view, the content of the primary hydroxyl group: the content of the secondary hydroxyl group = 5:95 to 50:50, particularly preferably in the range of 10:90 to 30:70. The content ratio of the primary hydroxyl group and the secondary hydroxyl group is a value estimated from the content of the fatty acid of the raw material.

From the viewpoint of bending resistance of the coating film, it is preferable to use the component (A1) having a hydroxyl value in the range of 150 to 400 mgKOH / g, preferably 155 to 300 mgKOH / g.

The number average molecular weight of the component (A1) is preferably in the range of 200 to 2,000 from the viewpoint of compatibility with other components and coating workability.

In the present invention, the polyol (A) may contain a polyol other than the component (A1).

In a preferred embodiment of the present invention, as the polyol other than the component (A1), at least one polyol selected from the group consisting of polycaprolactone diol, polycaprolactone triol, polycaprolactone tetraol, polycarbonate diol, and polyacrylate polyol ( A2) can be used.

<Polyprethane (A2)>
Polycaprolactone polyol can be obtained, for example, by ring-opening polymerization of ε-caprolactone using a divalent to tetravalent polyhydric alcohol as an initiator. Examples of the dihydric or higher polyhydric alcohol include ethylene glycol, glycerin, trimethylolethane, trimethylolpropane, diglycerin, ditrimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, and tris (2-hydroxy). Examples thereof include polyhydric alcohol compounds obtained by reacting isocyanuric acid and dimethylolalkanoic acid with a monoepoxy compound (for example, “Cadula E10; glycidyl ester of synthetic highly branched saturated fatty acid” manufactured by HEXION Specialty Chemicals). .. These can be used alone or in combination of two or more.

Further, as the polycaprolactone polyol, a commercially available product can be used. Examples of commercially available products include "Plaxel 205", "Plaxel 205H", "Plaxel L205AL", "Plaxel C205U", "Plaxel 208", and "Plaxel 210", which are the Pluxel 200 series manufactured by Daicel Chemical Industries, Ltd. "Plaxel 210N", "Plaxel 210CP", "Plaxel 212", "Plaxel 212AL", "Plaxel 220", "Plaxel 220N", "Plaxel 220CPB", "Plaxel 220UA", "Plaxel 303", which is the Pluxel 300 series, "Plaxel 305", "Plaxel 308", "Plaxel 309", "Plaxel 312", "Plaxel 320", "Plaxel 320AL", "Plaxel 410", etc., and "TONE301", "TONE305" manufactured by Dow Chemical Co., Ltd. Solvay Chemicals, Inc. Examples thereof include "Capa 4101", "Capa 2043", "Capa 3022", and "Capa 3091" manufactured by the same company.

Among the polycaprolactone polyols, from the viewpoint of bending resistance and impact resistance, the hydroxyl value is in the range of 100 to 700 mgKOH / g, further 130 to 600 mgKOH / g, and more particularly in the range of 150 to 500 mgKOH / g, and the number average molecular weight. Is in the range of 200 to 1,800, and those having two or more hydroxyl groups in one molecule are preferable.

Specifically, among the polycaprolactone polyols, polycaprolactone triol and polycaprolactone tetraol are preferable from the viewpoint of bending resistance, impact resistance and curability.

Polycarbonate diol can be obtained, for example, by reacting a diol component with a carbonylating agent. Examples of the carbonylating agent constituting the polycarbonate diol include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, diphenyl carbonate, diphenyl carbonate, and phosgene. Examples of the diol component of the polycarbonate diol include aliphatic diols and alicyclic diols, and specific examples thereof include 1,4-butanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol. , Aliper diols such as diethylene glycol, alicyclic diols such as 1,4-cyclohexanediol, ester diols such as bis (hydroxyethyl) terephthalate, and aromatic diols such as alkylene oxide adducts of bisphenol A.

As the polycarbonate diol, a commercially available product can be used. Examples of commercially available products include "Plaxel CD CD205", "Plaxel CD CD205PL", "Plaxel CD CD205HL", "Plaxel CD CD210", "Plaxel CD CD210PL", and Asahi Kasei Corporation manufactured by Daicel Chemical Industry Co., Ltd. "Duranol T5652", "Duranol T5651", "Duranol T5650J", "Duranol 5650E", "Duranol G4672", "Duranol T4671", "Duranol T4692", "Duranol T4691" and the like.

These polycarbonate diols can be used alone or in combination of two or more.

Among the polycarbonate diols, from the viewpoint of bending resistance and impact resistance, the hydroxyl value is in the range of 110 to 700 mgKOH / g, further 130 to 600 mgKOH / g, and more particularly in the range of 150 to 500 mgKOH / g, and the number average molecular weight is 200. Those in the range of ~ 1,800 are preferable.

As the polyacrylate polyol, usually, a hydroxyl group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer can be used in a method known per se, for example, in an organic solvent. It can be produced by copolymerizing by a method such as the solution polymerization method of.

The hydroxyl group-containing polymerizable unsaturated monomer is a compound having one or more hydroxyl groups and one or more polymerizable unsaturated bonds in one molecule, and specifically, for example, 2-hydroxyethyl (meth) acrylate and 2-hydroxy. Propyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 7-hydroxyheptyl (meth) acrylate , 8-Hydroxyoctyl (meth) acrylate or the like (meth) acrylic acid and a divalent alcohol having 2 to 8 carbon atoms; Examples thereof include a monoesterified ε-caprolactone modified product; N-hydroxymethyl (meth) acrylamide; an allyl alcohol, and a (meth) acrylate having a polyoxyethylene chain having a hydroxyl group at the molecular end. In the present invention, the polymerizable unsaturated monomer having an ultraviolet absorbing functional group such as 2-hydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, which will be described later, is a hydroxyl group-containing polymerizable unsaturated monomer. Instead, it is included in other polymerizable unsaturated monomers that can be copolymerized with the hydroxyl group-containing polymerizable unsaturated monomers.

Examples of other polymerizable unsaturated monomers copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and i-propyl (. Meta) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) Acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, "isostearyl acrylate (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd.)", cyclohexyl (meth) acrylate, methyl Alkyl or cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylates, t-butylcyclohexyl (meth) acrylates, V clododecyl (meth) acrylates; polymerizable unsaturated monomers having isobornyl groups such as isobornyl (meth) acrylates; adamantyl Polymerizable unsaturated monomer having an adamantyl group such as (meth) acrylate; vinyl aromatic compound such as styrene, α-methylstyrene, vinyltoluene; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane , Γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane and other polymerizable unsaturated monomers having an alkoxysilyl group; perfluorobutylethyl (meth) acrylate, perfluorooctylethyl Perfluoroalkyl (meth) acrylates such as (meth) acrylates; polymerizable unsaturated monomers having fluorinated alkyl groups such as fluoroolefins; polymerizable unsaturated monomers having photopolymerizable functional groups such as maleimide groups; N-vinyl Vinyl compounds such as pyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate; carboxyl group-containing polymerizable unsaturated monomers such as (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate; (meth) Acrylonitrile, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, glycidyl (meth) acrylate and amination Nitrogen-containing polymerizable unsaturated monomer such as an adduct with a mixture; polymerization having two or more polymerizable unsaturated groups in one molecule such as allyl (meth) acrylate and 1,6-hexanediol di (meth) acrylate. Sexual unsaturated monomer; glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexyl Epoxy group-containing polymerizable unsaturated monomer such as propyl (meth) acrylate and acryloyl glycidyl ether; (meth) acrylate having a polyoxyethylene chain having an alkoxy group at the molecular end; 2-acrylamide-2-methylpropanesulfonic acid, allyl Polymerizable unsaturated monomer having a sulfonic acid group such as sulfonic acid, sodium styrene sulfonic acid salt, sulfoethyl methacrylate and its sodium salt, ammonium salt; 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2- A polymerizable unsaturated monomer having a phosphate group such as acryloyloxypropyl acid phosphate and 2-methacryloyloxypropyl acid phosphate; 2-hydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2-hydroxy-4 -(3-Acryloyloxy-2-hydroxypropoxy) benzophenone, 2,2'-dihydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2,2'-dihydroxy-4- (3-acryloyloxy) Polymerizable unsaturated monomer with UV-absorbing functional groups such as -2-hydroxypropoxy) benzophenone, 2- (2'-hydroxy-5'-methacryloyloxyethylphenyl) -2H-benzotriazole; 4- (meth) acryloyl Oxy-1,2,2,6,6-pentamethylpiperidin, 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-cyano-4- (meth) acryloylamino-2, 2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidin, 1- (meth) acryloyl-4-cyano-4- (Meta) Acryloylamino-2,2,6,6-tetramethylpiperidin, 4-croto Noyloxy-2,2,6,6-tetramethylpiperidin, 4-crotonoylamino-2,2,6,6-tetramethylpiperidin, 1-crotonoyl-4-crotonoyloxy-2,2,6,6- UV-stable polymerizable unsaturated monomers such as tetramethylpiperidin; achlorine, diacetoneacrylamide, diacetonemethacrylamide, acetoacetoxyethyl methacrylate, formylstyrene, vinyl alkyl ketones with 4-7 carbon atoms (eg, vinylmethyl) Examples thereof include polymerizable unsaturated monomer compounds having a carbonyl group such as ketones, vinyl ethyl ketones, and vinyl butyl ketones), and these can be used alone or in combination of two or more.

Polyacrylate polyols are generally in the range of 30 to 300 mgKOH / g, particularly 40 to 250 mgKOH / g, and more particularly 50 to 200 mgKOH / g from the viewpoint of curability at low temperature and the water resistance of the obtained coating film. It preferably has a hydroxyl value.

Polyacrylate polyols generally preferably have a weight average molecular weight in the range of 3,000 to 100,000, especially 3,000 to 50,000, and even more particularly 4,000 to 30,000.

The "weight average molecular weight" and "number average molecular weight" in the present specification are calculated based on the molecular weight of standard polystyrene from a chromatogram measured by a gel permeation chromatograph according to the method described in JIS K 0124-2011. It is the value that was set. As the gel permeation chromatograph, "HLC8120GPC" (manufactured by Tosoh Corporation) was used. Four columns, "TSKgel G-4000HXL", "TSKgel G-3000HXL", "TSKgel G-2500HXL", and "TSKgel G-2000HXL" (all manufactured by Tosoh Corporation, trade name) were used. Mobile phase; tetrahydrofuran, measurement temperature; 40 ° C., flow rate; 1 m1 / min, detector; RI conditions.

As the polyacrylate polyol, from the viewpoint of curability and impact resistance, as a hydroxyl group-containing polymerizable unsaturated monomer, a (meth) acrylate having a polycaprolactone skeleton was copolymerized, and a hydroxybutyl acrylate (HBA) was copolymerized. The one is preferable.

The proportion of the component (A1) and the component (A2) used is not particularly limited, but from the viewpoint of finishability and impact resistance, the blending amount of the component (A1) is 10 with respect to 100 parts by mass of the component (A). It is preferably ~ 80 parts by mass, and more preferably 10 to 70 parts by mass. Further, from the viewpoint of finishability, bending resistance and water resistance, the blending amount of the component (A2) is preferably 20 to 90 parts by mass with respect to 100 parts by mass of the component (A), and is 30 to 90 parts by mass. It is more preferable that it is a part. These components (A) can be used alone or in combination of two or more.

<Other polyols (A3)>
In the present invention, as the polyol (A), other polyols other than the components (A1) and (A2) may be used. Other polyols are polyol components that are not classified into component (A1) and component (A2), such as polyhydric alcohols, polyester polyols, polyether polyols, polyacetal polyols, polyesteramide polyols or polythioether polyols, and polyether esters. Polyesters, polybutadiene polyols, and polyisoprene polyols can also be used as polyols. Examples of the above-mentioned polyether ester polyol include those obtained by reacting the above-mentioned polyether polyol with a polybasic acid to make a polyester, and a molecule obtained by a ring-opening copolymerization reaction of an epoxy compound and an acid anhydride. Examples thereof include those having both a polyether and a polyester segment. Other examples include hydroxyl group-containing resins. These can be used alone or in combination of two or more.

Examples of the polyether polyol include those obtained by ring-opening addition polymerization of ethylene glycol, propylene glycol, glycerin, pentaerythritol and the like as an initiator, and ethylene oxide, propylene oxide or a mixture thereof, for example. Examples thereof include polytetramethylene ether glycol obtained by ring-opening polymerization of tetrahydrofuran.

The polyhydric alcohols other than the above (A1) and (A2) are compounds having two hydroxyl groups in one molecule, and are aliphatic diols, aromatic diols, polyethylene glycols, polypropylene glycols, and polybutylene glycols exemplified above. Polyetherdiols such as glycerin, trimethylolethane, trimethylolpropane, diglycerin, triglycerin, 1,2,6-hexanetriol, pentaerythritol, dipentaerythritol, tris (2-hydroxyethyl) isocyanurate, sorbitol. , Sugars, mannittes and other trihydric or higher alcohols; examples thereof include polyester polyols obtained by reacting these trivalent or higher valent alcohols with a polybasic acid such as an acid anhydride.

Examples of the other hydroxyl group-containing resin include resins having a hydroxyl group, such as a polyether resin, a polycarbonate resin, a polyurethane resin, an epoxy resin, and an alkyd resin. These can be used alone or in combination of two or more.

The polyol (A3) can be contained as long as the coating film performance is not impaired. When the polyol (A3) is blended, the blending ratio is preferably 30% by mass or less based on the total amount of the resin solid content of the polyol (A).

<Polyisocyanate compound (B)>
The polyisocyanate compound (B) is a compound having at least two isocyanate groups in one molecule, and is, for example, an aliphatic polyisocyanate, an alicyclic polyisocyanate, an aromatic aliphatic polyisocyanate, an aromatic polyisocyanate, or the like. Examples thereof include derivatives of polyisocyanates.

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, and 1,3. An aliphatic diisocyanate such as −butylene diisocyanate, 2,4,4 | or 2,2,4-trimethylhexamethylene diisocyanate, diisocyanate dimerate, methyl 2,6-diisocyanatohexanate (common name: lysine diisocyanate); 2 , 6-Diisocyanatohexanoic acid 2-isocyanatoethyl, 1,6-diisocyanato-3-isocyanatomethylhexane, 1,4,8-triisocyanatooctane, 1,6,11-triisocyanatoundecane, 1, , 8-Diisocyanato-4-isocyanatomethyloctane, 1,3,6-triisocyanatohexane, 2,5,7-trimethyl-1,8-diisocyanato-5-isocyanatomethyloctane and other aliphatic triisocyanates, etc. Can be mentioned.

Examples of the alicyclic polyisocyanate include 1,3-cyclopentenediisocyanate, 1,4-cyclohexanediisocyanate, 1,3-cyclohexanediisocyanate, and 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate (common name). : Isophorone diisocyanate), 4-methyl-1,3-cyclohexylene diisocyanate (common name: hydrogenated TDI), 2-methyl-1,3-cyclohexylene diisocyanate, 1,3- or 1,4-bis (isocyanato) Alicyclic diisocyanates such as methyl) cyclohexane (common name: hydrogenated xylylene diisocyanate) or a mixture thereof, methylenebis (4,1-cyclohexanediyl) diisocyanate (common name: hydrogenated MDI), norbornan diisocyanate; 1,3,5 -Triisocyanatocyclohexane, 1,3,5-trimethylisocyanatocyclohexane, 2- (3-isocyanatopropyl) -2,5-di (isocyanatomethyl) -bicyclo (2.2.1) heptane, 2- (3-Isocyanatopropyl) -2,6-di (isocyanatomethyl) -bicyclo (2.2.1) heptane, 3- (3-isocyanatopropyl) -2,5-di (isocyanatomethyl)- Bicyclo (2.2.1) heptane, 5- (2-isocyanatoethyl) -2-isocyanatomethyl-3- (3-isocyanatopropyl) -bicyclo (2.2.1) heptane, 6- (2) -Isocyanatoethyl) -2-isocyanatomethyl-3- (3-isocyanatopropyl) -bicyclo (2.2.1) heptane, 5- (2-isocyanatoethyl) -2-isocyanatomethyl-2- (3-Isocyanatopropyl) -bicyclo (2.2.1) -heptane, 6- (2-isocyanatoethyl) -2-isocyanatomethyl-2- (3-isocyanatopropyl) -bicyclo (2.2) .1) An alicyclic triisocyanate such as heptane can be mentioned.

Examples of the aromatic polyisocyanate include methylenebis (1,4-phenylene) diisocyanate (common name: MDI), 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω, ω'-diisocyanato-1. , 4-Diethylbenzene, 1,3- or 1,4-bis (1-isocyanato-1-methylethyl) benzene (common name: tetramethylxylylene diisocyanate) or a mixture thereof, m-phenylenediocyanate, p-phenylenediisocyanate, 4,4'-Diphenyldiisocyanate, 1,5-naphthalenediocyanate, 2,4-tolylene diisocyanate (common name: 2,4-TDI) or 2,6-tolylene diisocyanate (common name: 2,6-TDI) Or a mixture thereof, aromatic diisocyanates such as 4,4'-toluidin diisocyanate, 4,4'-diphenyl ether diisocyanate; 1,3,5-triisocyanatomethylbenzene, triphenylmethane-4,4', 4''- Aromatic triisocyanates such as triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene; 4,4'-diphenylmethane-2,2', 5,5'-tetraisocyanate Aromatic tetraisocyanates and the like can be mentioned.

Examples of the polyisocyanate derivative include the above-mentioned polyisocyanate dimer, trimmer, biuret, allophanate, uretdione, uretoimine, isocyanurate, oxadiazine trione, and polymethylene polyphenyl polyisocyanate (Crude MDI, Polymeric MDI). , Crude TDI and the like.

The polyisocyanate and its derivatives may be used alone or in combination of two or more. Among these polyisocyanates, aliphatic diisocyanates, alicyclic diisocyanates and derivatives thereof are preferable.

Further, as the polyisocyanate compound (B), a prepolymer obtained by reacting the polyisocyanate and its derivative with a compound capable of reacting with the polyisocyanate under the condition of excess isocyanate group may be used. Examples of the compound capable of reacting with the polyisocyanate include compounds having an active hydrogen group such as a hydroxyl group and an amino group. Specific examples thereof include polyhydric alcohols, low molecular weight polyester resins, amines and water. Can be used.

The polyisocyanate compound (B) is a polymer of an isocyanate group-containing polymerizable unsaturated monomer, or a polymerizable unsaturated monomer other than the isocyanate group-containing polymerizable unsaturated monomer and the isocyanate group-containing polymerizable unsaturated monomer. A copolymer with a monomer may be used.

As the polyisocyanate compound (B), a blocked polyisocyanate compound in which the isocyanate group contained in the polyisocyanate compound is blocked may be used. As the blocking agent, for example, an active methylene compound such as a phenol compound; a lactam compound; an alcohol compound; an oxime compound; a mercaptan compound; dimethyl malonate; or a diethyl malonate can be preferably used. Blocking can be easily performed by mixing an unblocked polyisocyanate compound with a blocking agent. These polyisocyanate compounds can be used alone or in combination of two or more, and an unblocked polyisocyanate compound and a blocked polyisocyanate compound can also be used in combination.

As the polyisocyanate compound (B), hexamethylene diisocyanate (HDI) and / or isophorone diisocyanate (IPDI) isocyanurate, biuret, allophanate, trimethylolpropane (TMP) adduct and the like are preferable, particularly from the viewpoint of water resistance. In particular, isocyanurate of hexamethylene diisocyanate is preferable.

Further, from the viewpoint of impact resistance, the polyisocyanate compound (B) has an average number of isocyanate functional groups in one molecule of 1.9 to 6, further 2.5 to 5, and particularly in the range of 2.6 to 6. It is preferably inside.

The blending ratio of the polyisocyanate compound (B) and the polyol (A) is the hydroxyl group (NCO) of the polyisocyanate compound (B) and the hydroxyl group (A) of the polyol (A) from the viewpoint of the appearance of the coating film and the impact resistance. The molar ratio with OH) is more preferably in the range of NCO / OH = 0.5 / 1.0 to 1.5 / 1.0, more preferably 0.7 / 1.0 to 1.3 / 1.0. ..

<Curing catalyst (C)>
The coating composition of the present invention is characterized in that the curing catalyst (C) contains (C1) a bismuth compound at least as a part thereof.

<Bismuth compound (C1)>
Examples of the bismuth compound (C1) include bismuth carboxylate. Specifically, for example, bismuth hexanate (trivalent), bismuth octanate (trivalent), bismuth 2-ethylhexanoate (trivalent), bismuth oleate (trivalent), bismuth neodecanoate (trivalent) ( Other names: bismuth versatic acid), bismuth naphthenate (trivalent) and the like. Of these, bismuth neodecanoate, bismuth oleate, and bismuth naphthenate are particularly preferable from the viewpoints of curability, storability, and water resistance of the obtained coating film. These bismuth compounds (C1) may be used alone or in combination of two or more.

The content of the bismuth compound (C1) is 0.005 to 4 parts by mass, particularly 0.1 to 2 parts by mass, based on 100 parts by mass of the solid content of the polyol (A) from the viewpoint of achieving both curability and pot life. It is preferably within the range of.

<N-substituted imidazole compound (C2)>
The coating composition of the present invention can contain an N-substituted imidazole compound (C2) in the curing catalyst (C).

The N-substituted imidazole compound is a compound represented by the following general formula (1).

(In the formula (1), R ₁ represents any of an alkyl group having 1 to 4 carbon atoms, a phenyl group, a benzyl group and a vinyl group, and R ₂ , R ₃ and R ₄ are H or 1 to 4 carbon atoms. (Indicates the alkyl group of.).

Specific examples thereof include N-vinylimidazole, N-methylimidazole, N-ethylimidazole, N-phenylimidazole, N-benzyl imidazole, 1,2-dimethylimidazole, N-butyl imidazole and N-isobutyl imidazole. Of these, 1,2-dimethylimidazole is particularly preferable from the viewpoint of curability and suppression of foaming. These N-substituted imidazole compounds (C2) may be used alone or in combination of two or more.

When the N-substituted imidazole compound (C2) is used, its content is 100 mass by mass of the solid content of the polyol (A) in terms of the balance between the delay in pot life (pot life) and curability and the finish (inhibition of foaming). It is preferably in the range of 0.005 to 8 parts by mass, particularly 0.1 to 3 parts by mass, based on the portion.

In the coating composition of the present invention, a curing catalyst other than the (C1) bismuth compound and the N-substituted imidazole compound (C2) may be used as the curing catalyst (C).

<Carboxylic acid (D) with 8 or more carbon atoms>
The present invention is characterized in that the carboxylic acid (D) having 8 or more carbon atoms is contained in an amount of 0.1 to 10 parts by mass based on 100 parts by mass of the solid content of the polyol (A).

Specific examples of the carboxylic acid having 8 or more carbon atoms include the above-mentioned octanoic acid (also known as 2-ethylhexic acid [linear] or capric acid [branched chain], both of which have 8 carbon atoms) and pelargonic acid ( Alias: nonanoic acid, 9 carbon atoms), capric acid (also known as decanoic acid, 10 carbon atoms), neodecanoic acid (11 carbon atoms), lauric acid (also known as dodecanoic acid, 12 carbon atoms), tridecanoic acid (13 carbon atoms) ), Myristic acid (also known as tetradecanoic acid, 14 carbon atoms), pentadecanoic acid (15 carbon atoms), palmitic acid (also known as hexadecanoic acid, 16 carbon atoms), margaric acid (also known as heptadecanoic acid, 17 carbon atoms), stearer. Saturated fatty acids such as acids (also known as octadecanoic acid, 18 carbons), naphthenic acid (10 carbons), stearic acid (also known as octadecanoic acid, 18 carbons); oleic acid (18 carbons), erucic acid (18 carbons) 22) and other unsaturated fatty acids can be mentioned. From the viewpoint of curability and storage stability of the composition, a carboxylic acid having 11 to 18 carbon atoms is preferable, and from the viewpoint of finishability, at least one selected from neodecanoic acid, lauric acid and tridecanoic acid is preferable.

The content of the carboxylic acid (D) having 8 or more carbon atoms is based on 100 parts by mass of the solid content of the polyol (A) from the viewpoint of storage stability, curability and flexibility of the coating film. It is preferably in the range of 0.1 to 10 parts by mass, more preferably 0.3 to 3 parts by mass.

The present invention is characterized by containing a polyol (A1) having a constituent unit derived from a fatty acid having 8 or more carbon atoms, a bismuth compound (C1), and a specific amount of a carboxylic acid (D) having 8 or more carbon atoms. It is a composition, and by using the present invention, a coating film having excellent curability, appearance, water resistance, chemical resistance and impact resistance can be obtained even under high humidity conditions. The reason is not clear, but the synergistic effect of each component makes the paint and the coating film less compatible with water and becomes hydrophobic, so that deterioration of the coating composition over time is suppressed, and urea bonding occurs during the formation of the coating film. It is presumed that the formation ratio of urethane bonds is increased by suppressing the formation ratio of the coating film, and the coating film composition and coating film of stable quality are less likely to cause coating film defects due to foaming and do not deteriorate in water resistance and adhesiveness. Is considered to be possible.

<Hydrophobic silica particles (E)>
The coating composition of the present invention can contain silica particles.

In the present invention, when silica particles are contained, the hydrophobic silica particles (E) are particularly preferable from the viewpoint of storage stability, water resistance and viscosity adjustment of the composition.

Here, in the present invention, the hydrophobic silica particles (E) specifically refer to those having a hygroscopicity of less than 15% determined by the following method. Approximately 1 g of silica particles are placed in a pre-weighed 40 x 40 cm weighing bottle, dried in an electric constant temperature dryer at 110 ° C. for 3 hours, allowed to cool in a desiccator, and then the weight of the silica particles is precisely weighed. , The weight increase was measured in a desiccator prepared at a relative humidity of 60%, and the mixture was adsorbed until the adsorption amount became equilibrium. The amount of weight increase at the time of equilibrium was measured, and the weight increase rate (%) based on the dried product at 110 ° C. was defined as the moisture absorption rate.

If the moisture absorption rate is less than 15%, even if it is untreated, the surface of the raw material silica (e) is surfaced with a silylating agent such as alkylchlorosilane, halogenated silane, dimethylsiloxane, hexamethyldisiloxane, etc. The surface of the hydroxyl group of silica may be hydrophobized with a silyl group-Si-Rn, for example, a trimethylsilyl group or polyorganosiloxane, after being treated with polyorganosiloxane or polyalkoxysiloxane, or silazane.

Examples of silica (e) used as a raw material for component (E) include dry silica, wet silica, silica gel, calcium ion exchange silica fine particles, colloidal silica and the like.

By containing the hydrophobic silica particles (E) having a hygroscopicity of less than 15%, preferably less than 0.1 to 6%, the appearance of the coating film and the appearance of the coating film and the storage stability of the composition are not affected. It may improve water resistance and chemical resistance.

Although the reason is not clear, the coating composition of the present invention can be made more hydrophobic, and the viscosity (pseudoplasticity) of the composition can be appropriately adjusted from immediately after application to drying. Since the amount of the rheology control agent added can be relatively suppressed, it is considered that a coating film having excellent water resistance, chemical resistance, and appearance of the coating film can be obtained.

Further, as the component (E), from the viewpoint of finishability such as sagging and defoaming property, the viscosity of the sample to which the component (E) is added, which will be described later, is more preferably 3,000 to 20, more than 2,500 mPa · sec or more. Hydrophobic silica particles (E) in the range of 000 mPa · sec are preferable.

In the present specification, the viscosity value of the sample to which the hydrophobic silica particles (E) are added is determined by a rotational viscometer (for example, E-type viscometer, VISCOMETAE TV-20: manufactured by Toki Sangyo Co., Ltd., cone rotor number: It is a value measured at 1 ° 34'× R24, rotation speed: 1 rpm, measurement temperature 25 ° C.).

The sample was prepared by adding hydrophobic silica (E) to 100 parts by mass of a solid content of polyol (A1), for example, Sovermol 815 in an environment of 25 ° C. and 50% relative humidity with stirring with 10 parts by mass of a disper, under the same conditions. A sample was used after being cured for 5 hours.

The viscosity (that is, the structural viscosity index (TI)) of the viscosity of the polyol (A1) due to the addition of the hydrophobic silica particles (E) is preferably 1.1 or more, more preferably in the range of 1.3 to 10.0. Within each of the above ranges, the viscosity of the polyol (A1) by adding the hydrophobic silica particles (E) is appropriately lowered, and a sufficient coating liquid is applied onto the object to be coated. It is suitable from the viewpoint of achieving a good balance between suppressing the flow of the paint and improving the sagging property.

The structural viscosity index TI value is defined by the following equation (1).

TI value = Va / Vb ... (1)
(However, in the formula (1), Va is the apparent viscosity (mPa · sec) measured at a rotation speed of 1 time / minute with an E-type viscometer (same as above) at a temperature of 25 ° C., and Vb is Similarly, the viscosity (mPa · sec) measured at a rotation speed of 10 times / minute).

The average primary particle size of the hydrophobic silica particles may be 1.0 to 50 μm for matting use. In particular, from the viewpoint of coating workability, water resistance and chemical resistance of the obtained coating film, it is preferable to contain hydrophobic silica particles (E) having an average primary particle size of 5 to 30 μm, and further, the average primary particle size is It is preferably in the range of 7 to 10 μm.

In the present specification, the average primary particle size of the hydrophobic silica particles refers to the D50 value of the particle size distribution measured by the laser scattering method. The D50 value is a particle size at which the integrated particle size distribution from the small particle size side is 50% from the volume-based particle size distribution. In the present specification, the volume-based particle size distribution of silica particles was measured using a laser diffraction / scattering type particle size distribution measuring device “Microtrack NT3300” (trade name, manufactured by Nikkiso Co., Ltd.). At that time, as a pretreatment, silica particles were added to a mixed solvent of acetone and isopropyl alcohol and dispersed by applying ultrasonic waves for 1 minute, and the concentration of silica particles was adjusted to a concentration within a predetermined transmittance range set in the apparatus. ..

As the hydrophobic silica particles (E) having a moisture absorption rate of less than 15%, a commercially available product can be used. , Silysia 436, Silysia 450, etc.), SYLPHOBIC series (SYLOPHOBIC 100, SYLPHOBIC 200, SYLPHOBIC 702, SYLPHOBIC 4004, etc.) HK460, ACEMATT HK400, ACEMATT OK412, ACEMATT TS100, ACEMATT 3200, ACEMATT 3300, ACEMATT 3600, etc.) R805, AEROSIL R972, etc.) and the like.

These various materials can be used alone or in combination of two or more.

Among them, as a commercially available product of hydrophobic silica particles having an average primary particle size of 5 to 30 μm, for example, from the viewpoint that the viscosity can be adjusted by adding a small amount, ACEMATT OK412, ACEMATT 3200, ACEMATT 3300 and ACEMATT 3300 manufactured by Evonik Degussa Japan Co., Ltd. SYLPHOBIC 4004 manufactured by Fuji Silysia Chemical Ltd. is preferable.

When the hydrophobic silica particles (E) are contained, the content is 1 to 50 with respect to 100 parts by mass of the solid content of the polyol (A) in terms of finishability (suppression of foaming), chemical resistance and viscosity control. It is preferably parts by mass, preferably 5 to 20 parts by mass.

When the hydrophobic silica particles (E) having an average primary particle diameter of 5 to 30 μm are contained, the content is preferably 2 to 20 parts by mass with respect to 100 parts by mass of the solid content of the polyol (A).

<Rheology control agent (F)>
The coating composition of the present invention may contain a rheology control agent. In particular, an amide-based rheology control agent (F) is preferable. The amide-based rheology control agent (F) is a compound having a -NH-CO- bond in the molecule, and can exhibit thixotropy by adding and mixing it with the coating composition of the present invention. It is considered that the -NH-CO- bond of the amide system develops viscosity when the hydroxyl group of the polyol (A) is loosely bonded by a hydrogen bond.

As the amide-based rheology control agent, those known as so-called amide-based waxes can be used. Specific examples thereof include fatty acid amide or an oligomer thereof, or a modified product thereof (modified polyamide) or a mixture thereof as an active ingredient.

The fatty acid amide is a fatty acid amide obtained by reacting an amine with a carboxylic acid. As the amine, a diamine having 2 to 6 carbon atoms such as ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, and hexamethylenediamine is preferably used, and in this case, an oligomer is usually synthesized.

The aliphatic carboxylic acid may be a monocarboxylic acid having 2 to 18 carbon atoms, or a dicarboxylic acid such as oxalic acid, succinic acid, fumaric acid, glutaric acid, adipic acid, suberic acid, azelaic acid, and sebacic acid. Furthermore, fatty acids derived from natural fats and oils such as castor oil fatty acids, dimer acids obtained by polymerizing unsaturated fatty acids, and the like can be used, and in the case of unsaturated carboxylic acids, hydrogenated ones are preferable.

As commercially available fatty acid amides, those in a powder state and those in a paste state are known. The paste state is generally diluted with a solvent such as xylene or alcohol.

For example, fatty acid amide paste type (DISPARLON 6900-20X, DISPARLON 6900-10X, DISPARLON A603-20X, DISPARLON A603-10X, DISPARLON A670-20M, DISPARLON 6810-20X, DISPARLON 6900-20X, DISPARLON 6900-10X, DISPARLON A603-10X, DISPARLON 6810-20X, DISPARLON, which are commercially available from Kusumoto Kasei Co., Ltd. 20X, DISPARLON 6820-20M, DISPARLON 6820-10M, DISPARLON FS-6010, DISPARLON PFA-131, DISPARLON PFA-231, DISPARLON F-9020, DISPARLON F-9030, DISPARLON F-9040, DISPARLON F-9040 Polyolefin amide (DISPARLON NS-5010, NS5025, DISPARLON NS-5210, DISPARLON NS-5310, etc.), higher fatty acid amide paste commercially available from Kyoei Kagaku Co., Ltd. (Taren series such as Taren 7200-20 and Taren 7500-20) , BYK-405 manufactured by BYK Chemie Co., Ltd., AS-A T-75F manufactured by Itoh Oil Chemicals Co., Ltd., and the like can be used.

Further, when the amide-based rheology control agent is used with the hydrophobic silica particles (E), the viscosity (pseudoplasticity) of the composition can be appropriately adjusted, and the appearance of the coating film may be further improved. Is particularly preferable.

Examples of other rheology control agents include polyolefin oxides such as polyethylene oxide and polypropylene oxide, cellulose derivatives, and acrylic polymers.

As the polyolefin oxide-based wax, for example, polyethylene oxide is preferably made into fine particles to form a colloidal swelling dispersion, and examples thereof include those having an effect of preventing sedimentation and improving rheology. Specific examples of the polyethylene oxide wax include DISPARLON 4200-10, DISPARLON 4200-20, DISPARLON PF-911 manufactured by Kusumoto Kasei Co., Ltd., AS-AD-10A and AS- manufactured by Itoh Oil Chemicals Co., Ltd. AD-120 and the like can be mentioned.

Examples of the acrylic polymer include Cerney HPC-H, HPC-M, HPC-L, HPC-SL and HPC-SSL (manufactured by Nippon Soda Co., Ltd.), and Dianal BR series (Mitsubishi Rayon Co., Ltd.). Made) and the like.

Further, as other commercially available rheology control agents, specifically, DISPARLON Disparon KS-873N, DISPARLON 1850 (manufactured by Kusumoto Kasei Co., Ltd.), BYK-410 (manufactured by Big Chemie Japan Co., Ltd.), Primal RW Examples thereof include -12W (manufactured by Roam & Haas), AS-A T-20SF (manufactured by Itoh Oil Chemicals Co., Ltd.), and Setalux C-7176VB-60 (manufactured by AkzoNobel).

When the above rheology control agent is blended, one having thixotropy property and exhibiting viscosity when shearing force is no longer applied can be used. Therefore, in the present invention, the action of the paint to suppress sagging or the like is more strongly exerted between the time when the paint particles are applied to the object to be coated and the time when the paint particles are dried.

These various materials can be used alone or in combination of two or more.

When a rheology control agent is contained, the content thereof is less than 30 parts by mass and further 2 to 25 parts by mass with respect to 100 parts by mass of the solid content of the polyol (A) from the viewpoint of adjusting to a desired viscosity. It is preferably within the range of parts.

In particular, when an amide-based rheology control agent is used with the hydrophobic silica particles (E), the content of the polyol (A) is 100% by mass in terms of bending resistance and chemical resistance of the obtained coating film. It is particularly preferable that the viscosity can be sufficiently adjusted to a desired value within the range of less than 10 parts by mass and still 0.1 to 5 parts by weight.

<Defoamer (G)>
The coating composition of the present invention may contain an antifoaming agent, and examples of the antifoaming agent include polymers such as silicone-based, fluorine-based, acrylic-based, vinyl ether-based, and acetylene glycol-based polymers.

If a silicone-based or fluorine-based polymer is used as the defoaming agent (G), the finish may be inferior. As the defoaming agent containing no silicone or fluorine, acrylic-based or vinyl ether-based, And at least one selected from the acetylene glycol-based polymer group is preferred.

As the acrylic antifoaming agent, commercially available products can be used, for example, BYK-350, BYK-351, BYK-354, BYK-355, BYK-381, BYK-392, BYK-394, BYK-3441 (and above). , Big Chemie), DISPARLON OX-720EF, DISPARLON LAP-10, DISPARLON LAP-20, DISPARLON LAP-30, DISPARLON LF-1900 series (hereinafter, Kusumoto Kaseisha) and the like.

Commercially available products can be used as the vinyl defoamer, and DISPARLON UVX-188, DISPARLON UVX-189, DISPARLON UVX-190 (above, Kusumoto Kasei), BYK-051, BYK-052, BYK-053 (above). , Big Chemie) and the like.

Examples of the acetylene glycol-based antifoaming agent include Surfinol DF110D, Surfinol DF37, Envirogem AD-01, Orfin SPC, Orfin AF-103, Orfin AF-104 (above, Nissin Chemical Industry) and the like.

These various materials can be used alone or in combination of two or more.

When the defoaming agent (G) is contained, the amount added is 0 with respect to 100 parts by mass of the solid content of the polyol (A) from the viewpoint of defoaming effect and prevention of contamination due to bleeding on the coating film surface. .01 to 5 parts by mass is preferable.

<Other ingredients>
The coating composition of the present invention further comprises a compound having reactivity with an isocyanate group (for example, an amino compound), a fluororesin, and an ultraviolet absorber (for example, a benzotriazole-based absorber, triazine) as long as the coating performance is not impaired. Absorbents, salicylic acid derivative absorbers, benzophenone absorbers, etc.), light stabilizers (eg, hindered amines, etc.), coloring components, extender pigments (talc, clay, kaolin, barita, barium sulfate, barium carbonate, calcium carbonate) , Alumina white, etc.), resin particles, rust preventives, chelating agents (acetylacetone, etc.) plastics, solvents, pigment dispersants, surface conditioners, sedimentation inhibitors, and other known paint additives. Further, various additives such as a water repellent, an antifouling agent, an antiseptic, an antibacterial agent, and a conductive agent may be contained in order to give various functionalities to the surface of the coating film as long as the performance of the coating film is not impaired.

<Adjustment of paint composition>
The form of the coating composition of the present invention is not particularly limited, and may be any form of a water-based coating material, an organic solvent type coating material, and a solvent-free type coating material, but from the viewpoint of storage stability of the coating material composition. Therefore, it is preferable to use an organic solvent type paint or a non-aqueous dispersion type paint.

In the present specification, the water-based paint is a term to be contrasted with the organic solvent-type paint, and generally, water or a medium containing water as a main component (water-based medium), a coating-forming resin, a pigment, or the like is used. Means a paint in which is dispersed and / or dissolved. When the coating composition of the present invention is a water-based coating material, the content of water in the coating composition is in the range of 10 to 90% by mass, preferably 20 to 80% by mass, and more preferably 30 to 70% by mass. Is preferable.

The organic solvent type paint is a paint that does not substantially contain water as a solvent or that all or most of the solvent is an organic solvent. Examples of the organic solvent in the coating composition of the present invention include ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ethyl acetate, butyl acetate, methyl benzoate, ethyl ethoxypropionate, ethyl propionate, methyl propionate and the like. Esters; Ethers such as tetrahydrofuran, dioxane, dimethoxyethane; Glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, 3-methoxybutyl acetate; Examples include hydrogens and aliphatic hydrocarbons. The organic solvent can be used without particular limitation, but it is preferable that it does not contain toluene, xylene, or the like from the viewpoint of the influence on the human body and the environment.

The organic solvents can be appropriately combined and used according to the purpose of adjusting the viscosity, adjusting the coatability, and the like.

For the solid content of the coating composition of the present invention, it is necessary to adjust the solid content content to 15% by mass or more, particularly preferably within the range of 35 to 90% by mass, for coating workability and the amount of organic solvent discharged. It is preferable from the viewpoint of reduction.

In the present specification, the solid content means a residue excluding volatile components, and the residue may be solid or liquid at room temperature. The solid content mass can be calculated by taking the ratio of the amount of residual substance after drying to the mass before drying as the solid content ratio and multiplying the solid content ratio by the sample mass before drying.

From the viewpoint of storage stability and coating workability, the coating composition of the present invention is preferably a two-component coating material composed of a main agent containing a polyol (A) and a curing agent containing a polyisocyanate compound (B), and both immediately before use. It is preferable to mix and use. In the specification of the present application, the storage stability of the coating composition refers to the curability and appearance of the coating film when each main agent before the curing agent is stored under predetermined conditions and then the curing agent is added to form a cured coating film. , Flexibility, impact resistance, chemical resistance, water resistance, and other test items such as coating film physical properties and sagging properties are less likely to cause problems (in the examples of the present application, the evaluation results of the above test items are less than B). There is no one). Further, the components (C) to (G), a solvent such as water or an organic solvent, a pigment dispersant, a precipitation inhibitor, an antioxidant, various additives such as an ultraviolet absorber, etc. are used as either a main agent or a curing agent. It can be included as appropriate.

When the coating composition of the present invention is heat-cured, it may be a one-component coating material, and in that case, a blocked polyisocyanate compound may be used as the polyisocyanate compound (B). By the above heating, the blocking agent is removed and can be crosslinked with the hydroxyl group of the polyol (A) component.

<Coating film forming method>
The present invention provides a coating film forming method for forming a coating film by coating an object to be coated with the coating composition.

The object to be coated includes a plastic or metal base material, a base material on which a gel coating material containing an epoxy resin is laminated, a base material on which a primer coating material containing an epoxy resin is formed, or an epoxy on the base material. A gel coat material containing a resin is laminated, and a primer coating material containing an epoxy resin is further formed on the gel coat material, which can be preferably used.

<Metal base material>
The metal base material is not particularly limited as long as it is a metal, for example, the metal itself such as magnesium, aluminum, zinc, titanium, iron, nickel, chromium, gold, silver, copper, tin, platinum, palladium, zirconium, tungsten, and the like. Metallic materials such as alloys of at least two or more of these metals can be mentioned. Examples of the two or more kinds of metal materials include alloyed zinc such as Zn-Al, Zn-Ni, and Zn-Fe, stainless steel, and steel plated with the above metal material.

<Plastic base material>
As the plastic base material, polyolefin resins such as polyethylene resin and polypropylene resin; polyester resins such as polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate; styrene-butadiene block copolymer, styrene-acrylonitrile, acrylonitrile-butadiene Styrene resins such as -styrene (ABS), polystyrene, acrylonitrile-styrene-acrylate, polyamide resins such as nylon 6, nylon 6, 6, nylon 6,10 and metaxylylene adipamide, polymethyl methacrylate, methyl methacrylate. Acrylic resins such as ethyl acrylate; vinylidene chloride resins such as polyvinyl chloride resin and vinyl chloride-vinyl acetate, unsaturated polyester resins, phenol resins, melamine resins, urea resins, polyphenylene ether resins, polyoxymethylene resins, polyurethane resins, Examples thereof include resins such as epoxy resins and plastic materials such as various fiber-reinforced plastics (hereinafter, may be abbreviated as FRP). The plastic base material may be a hybrid resin of two or more kinds of resins.

The fiber reinforced plastic (FRP) means that the strength of the reinforced plastic is improved by including the reinforced fiber in the plastic.

As the reinforcing fiber used for FRP, any known reinforcing fiber such as glass fiber, aramid fiber, carbon fiber and the like can be used, and a plurality of types of reinforcing fibers can be used in combination. In particular, by including glass fiber and carbon fiber, the specific strength and specific elastic modulus are excellent as compared with the plastic base material itself. In order to obtain an FRP material that is lightweight and has excellent mechanical properties, it is preferable to use one type of reinforcing fiber or two or more types of reinforcing fibers, but glass fiber is particularly inexpensive and has high strength. It is preferable that it is contained. The ratio of the glass fiber contained in the reinforcing fiber is preferably 10 to 100% by mass.

As the FRP matrix resin (also called a base resin, which is a plastic that is a base material and is a base material after molding), the resins mentioned in the above section on plastic base materials, unsaturated polyester resins, and phenols are used. Resin or the like is used. In particular, an epoxy resin is preferable from the viewpoint of adhesion to reinforcing fibers, and any epoxy resin can be applied as long as it is suitable for FRP molding. A curing agent may be used, and examples of the curing agent include amine compounds, acid anhydride compounds, polyimide compounds, and imidazole compounds. It may be a thermoplastic resin using methyl methacrylate or the like.

Known FRP molding methods can be used, and examples thereof include a sheet molding compound (SMC) molding method, a resin infusion (RIMP) molding method, and a prepreg / autoclave press method, which are manufactured using a mold. Be done.

The surface of the metal base material, various plastic base materials, and molded parts is subjected to surface treatment such as degreasing, phosphate treatment, chromate treatment, composite oxide treatment, cleaning, and polishing using a detergent or solvent. In addition, an undercoat coating film (including a coating film formed of a gel coating material) may be formed on the undercoat coating material.

<Undercoat coating>
The undercoat coating film is a coating film formed under the coating film formed by the coating composition of the present invention, and the undercoat coating film for forming the undercoat coating film depends on the type and condition of the surface to be coated. Painted accordingly. By providing a film between the coating film and the coating film formed by the coating composition of the present invention, the adhesion to the surface to be coated and the impact resistance can be improved. Further, the undercoat coating film may be a plurality of layers in order to improve the adhesiveness. As the undercoat coating film, for example, when the base material is a metal base material, a coating film that can be obtained by coating and curing a primer coating material and / or a coating composition called an intermediate coating coating material known in the coating field. Membrane is mentioned. When the base material is an FRP base material, a coating film obtained by coating and curing the surface of an FRP product called a gel coat material can also be mentioned.

Specific components of the undercoat paint constituting the undercoat coating include, for example, a film-forming resin, a cross-linking agent, a coloring pigment, an extender pigment, a bright pigment, a rust preventive pigment, and a conductive pigment. The undercoat coating composition can be preferably used, and further, the undercoat coating composition can be used as an ultraviolet absorber, a light stabilizer, a curing catalyst, a plasticizer, an adhesion imparting agent, a compatibilizer, a defoaming agent, a viscosity modifier, and an antibacterial agent. A paint additive such as a rust agent and a surface conditioner can be appropriately contained.

Examples of the type of film-forming resin include polyols, acrylic resins, polyester resins, alkyd resins, urethane resins, polyolefin resins, epoxy resins, phenol resins, polyamide resins, and hydroxyl group-containing resins thereof. It can be used as a seed or in combination of two or more.

It may be cross-linked by blending a cross-linking agent, or may be substantially uncross-linked without a cross-linking agent. Further, the cross-linking may be performed by impregnation of the cross-linking agent contained in the upper coating film.

As the cross-linking agent, for example, an amino resin such as a melamine resin or a urea resin, a polyisocyanate compound, a blocked polyisocyanate compound or the like can be preferably used. As the undercoat coating composition, either an organic solvent type coating composition or a water-based coating composition may be used, or a solvent-free undercoat coating composition may be used.

From the viewpoint of impact resistance and adhesion to the surface to be coated, the coating composition of the present invention is preferably formed of a coating composition in which the undercoat coating film contains an epoxy resin and / or a gel coating material containing an epoxy resin. It is preferable to apply the coating on an object to be coated having an undercoat coating film. Specifically, a gel coat material containing an epoxy resin is laminated on the base material, a primer coating material containing an epoxy resin is formed on the base material, or a gel coat material containing an epoxy resin is laminated on the base material. , A primer coating material further containing an epoxy resin is formed on the gel coating material, and a material can be preferably used.

Here, the gel coating material refers to a coating composition for molding on the surface of an FRP base material or a metal using a mold. As a method of laminating the gel coat material, the inner surface of the mold is coated with a film-forming resin that can be the surface of the outer plate in advance to form a film, a reinforcing fiber base material is arranged on the gel coat material, the mold is closed, and then the mold is closed. The FRP resin is injected, cured, and demolded to transfer the coating to the surface of the FRP outer plate, or the fiber reinforced plastic material is preheated and molded in the mold, and then the obtained molding is performed. Examples thereof include a method in which the gel coating material is injected between the object and the inner wall of the mold, the gel coating material is cured, and then the coated molded product is taken out from the mold.

As the constituent component of the gel coat material, those listed in the section of the constituent component of the undercoat paint constituting the undercoat coating film can be used. As the film-forming resin, in addition to the resins mentioned in the above section of the undercoat coating film, any known resin such as polycarbonate resin, vinyl ester resin, unsaturated polyester resin, bismaleimide resin, and polyurea resin can be used. .. One or more of these resins can be used in combination, but from the viewpoint of adhesiveness, it is preferable to contain an epoxy resin as a part of the constituent components, and from the viewpoint of impact resistance, the polyol and aromatic isocyanate are cured. A gel coating material in which an epoxy resin is contained in a urethane curing composition using an agent is preferable.

The epoxy resin contained in the undercoat paint (including the gel coat material) is not particularly limited, and various ones can be used. For example, bifunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, biscresol fluorene type epoxy resin, bisphenol S type epoxy resin, t-butyl catechol type epoxy resin, and phenol novolac. Multivalent epoxy resins such as type epoxy resin, cresol novolac type epoxy resin, nonylphenol novolac type epoxy resin, epoxy ester resin obtained by modifying these epoxy resins with dibasic acid, alicyclic epoxy resin, polyglycol type epoxy resin, epoxy Group-containing acrylic resin and the like can be mentioned.

The method of applying the undercoat paint other than the gel coating material is not particularly limited, and can be applied by using a coating method known per se, for example, a roller, an air spray, an airless spray, a ricing gun, a universal gun, a brush, and a roll coater. It can be appropriately selected depending on the application of the base material and the like. The drying conditions can be any of heat drying, forced drying, and room temperature drying, depending on the type of undercoat paint used and the like.

<Other objects to be coated>
Further, the object to be coated other than the above may be an inorganic material such as glass, cement, concrete; wood; a fiber material (paper, cloth, etc.) as long as the adhesiveness is satisfactory.

Depending on these objects to be coated, degreasing treatment, surface treatment and the like can be appropriately performed.

In the method of the present invention, the coating composition of the present invention can be applied to the object to be coated by, for example, electrostatic coating, air spray, airless spray, roller, brush or the like. At that time, the film thickness is preferably in the range of 30 to 500 μm, more preferably in the range of 50 to 300 μm, based on the cured coating film, from the viewpoint of impact resistance. In the method of the present invention, a cured coating film can be obtained by, for example, drying and curing the coating film at room temperature (5 to 35 ° C.) after coating to a predetermined film thickness. The relative humidity (hereinafter sometimes abbreviated as RH) at the time of painting is preferably 70% or less and 60% or less. The curing time for drying at room temperature is preferably 1 day or longer, more preferably 3 days or longer. The coating film may be dried and cured by heating, and the temperature at the time of heating is preferably, for example, 30 to 100 ° C., more preferably 35 to 90 ° C. The heating time is preferably, for example, 5 to 120 minutes, more preferably 10 to 100 minutes. As the heating device, a drying furnace or a blower can be used.

The application of the object to be coated with the coating composition of the present invention is not particularly limited, and even for articles or parts thereof exposed to strong rain, wind, sand, etc., the coating environment is excellent, and water resistance and impact resistance are excellent. From the fact that a coating film having the above can be obtained. For example, blades of wind power generators, wings of aircraft and helicopters, automobiles and bicycles, bodies of construction machinery and their parts, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples. Unless otherwise specified, "parts" and "%" indicate "parts by mass" and "% by mass".

≪Creation of paint composition≫
(Example 1)
100 parts of castor oil (Note 1), 100 parts of TIPAQUE CR-95 (Note 30), 20 parts of HA-90T (Note 31), and 37.5 parts of butyl acetate were mixed and dispersed with a sand mill to obtain a dispersed paste. .. The obtained dispersed paste is mixed with 0.5 part of bismuth neodecanoate, 0.5 part of naphthenic acid and 1 equivalent of Sumijour N3300 (Note 33) with respect to the hydroxyl group in castor oil to obtain a solid content of 80%. By adding butyl acetate and stirring as described above, the coating composition No. I got 1. The obtained coating composition No. Regarding No. 1, the painting workability (pot life) (Note 36) described later was tested. Table 1 shows the evaluation results.

(Examples 2-72, Comparative Examples 1-12)
In Example 1, the coating composition No. 1 having a solid content of 80% shown in Tables 1 to 6 was obtained in the same manner as in Example 1 except that the formulations of the respective components were the formulations shown in Tables 1 to 6. 2-No. I got 83. Of the components in Tables 1 to 6, the amount of the solid content or the active ingredient content described in the note below indicates the amount of the solid content or the active ingredient (parts by mass).

The notes in the table are shown below.

(Note 1) Castor oil: Hydroxy group value 160 mgKOH / g, Castor oil polyol, Primary hydroxyl group content: Secondary hydroxyl group content = 0: 100
(Note 2) Sovermol 750: Product name, manufactured by BASF, hydroxyl value 315 mgKOH / g, polyol derived from palm oil, primary hydroxyl group content: secondary hydroxyl group content = 100: 0
(Note 3) Sovermol 760: Product name, hydroxyl value 390 mgKOH / g, polyol derived from soybean oil, primary hydroxyl group content: secondary hydroxyl group content = 100: 0
(Note 4) URIC H-81: Product name, manufactured by Itoh Oil Chemicals, hydroxyl group 340 mgKOH / g, polyol derived from castor oil, primary hydroxyl group content: secondary hydroxyl group content = 67: 33
(Note 5) URIC H-73X: Product name, manufactured by Itoh Oil Chemicals, hydroxyl group 270 mgKOH / g, castor oil-derived polyol, primary hydroxyl group content: secondary hydroxyl group content = 50:50,
(Note 6) Sovermol 815: Product name, manufactured by BASF, hydroxyl value 215 mgKOH / g, polyol derived from castor oil and palm oil, primary hydroxyl group content: secondary hydroxyl group content = 33:67
(Note 7) Sovermol 1095: Product name, manufactured by BASF, hydroxyl value 215 mgKOH / g, castor oil-derived polyol, primary hydroxyl group content: secondary hydroxyl group content = 20:80,
(Note 8) URIC H-854: Product name, manufactured by Itoh Oil Chemicals Co., Ltd., hydroxyl value 227.5 mgKOH / g, castor oil-derived polyol, primary hydroxyl group content: secondary hydroxyl group content = 14:86.

(Note 9) Duranol T5650J: Product name, manufactured by Asahi Kasei Chemicals Co., Ltd., hydroxyl value 110227.5 mgKOH / g, polycarbonate diol, number average molecular weight 800,
(Note 10) Praxel 205: Product name, polycaprolactone diol, number average molecular weight 530, hydroxyl value 212 mgKOH / g, manufactured by Daicel Corporation (Note 11) Praxel 305: Product name, polycaprolactone triol, number average molecule 550, hydroxyl value 305 mgKOH / G, manufactured by Daicel (Note 12) Praxel 308: Product name, polycaprolactone triol, number average molecule 850, hydroxyl value 195 mgKOH / g, manufactured by Daicel (Note 13) Capa 4101: Product name, polycaprolactone tetraol, number Average molecular weight 1,000, hydroxyl value 218 mgKOH / g, Solvay Chemicals, Inc. Made.

(Note 14) Polyacrylate polyol No. 1: 40 parts of butyl acetate and 40 parts of methoxypropyl acetate are charged in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a dropping device, and stirred at 130 ° C. while blowing nitrogen gas into the reaction vessel.
Styrene 5.0 parts n-Butyl acrylate 54.0 parts 2-Hydroxyethyl methacrylate 15.0 parts Praxel FM-3X (Product name, manufactured by Daicel Corporation, ε-caprolactone-modified hydroxyethyl methacrylate) 25.0 parts,
1.0 part of acrylic acid,
And V-59 (trade name, manufactured by Wako Pure Chemical Industries, Ltd., 2,2'-azobis (2-methylbutyronitrile, polymerization initiator) are added dropwise at a uniform rate over 3 hours, and at the same temperature. Aged for 2 hours.

Then, 10 parts of butyl acetate and V-59 (0.5 part of the mixture were added dropwise to the reaction vessel over 1 hour, and after the completion of the addition, the mixture was aged for 1 hour to obtain a polyacrylate polyol No. 1 solution having a solid content of 54%. The hydroxyl value of the obtained resin solid content was 94.4 mgKOH / g, and the weight average molecular weight was 10,000.

(Note 15) Polyacrylate polyol No. 2: 40 parts of butyl acetate and 40 parts of methoxypropyl acetate are charged in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a dropping device, and stirred at 130 ° C. while blowing nitrogen gas into the reaction vessel.
5.0 parts of styrene,
15.0 parts of methyl methacrylate,
n-Butyl acrylate 50.0 parts,
4-Hydroxybutyl Acrylate 29.0 Parts,
A mixture of 1.0 part of acrylic acid and 5.0 parts of V-59 (initiator) was added dropwise at a uniform rate over 3 hours, and the mixture was further aged at the same temperature for 2 hours.

Then, a mixture of 10 parts of butyl acetate and 0.5 part of V-59 (initiator) was added dropwise to the reaction vessel over 1 hour, and after the completion of the addition, the mixture was aged for 1 hour to obtain Polyacrylate polyol No. with a solid content of 54%. Two solutions were obtained. The hydroxyl value of the obtained resin solid content was 113 mgKOH / g, and the weight average molecular weight was 10,000.

(Note 16) 1,2-dimethylimidazole: a compound represented by the following formula (II)

(Note 17) 1-isobutyl-2-methylimidazole: a compound represented by the following formula (III)

(Note 18) 2-Methylimidazole: A compound represented by the following formula (IV)

(Note 19) Mizukasil P-526: Product name, manufactured by Mizusawa Industrial Chemicals, wet silica, untreated silica particles with an average primary particle size of 7 μm and a hygroscopicity of 4.5%,
(Note 20) ACEMATT HK440: Product name, manufactured by Evonik Degusa, dry silica, untreated silica particles with an average primary particle size of 14.5 μm and a moisture absorption rate of 5.5% (Note 21) AEROSIL R-972: Product name, Japan Dimethyldichlorosilane-modified silica particles manufactured by Aerosil, with an average primary particle diameter of 0.06 μm and a moisture absorption rate of 0.5%.
(Note 22) SYLPHOBIC 200: Product name, manufactured by Fuji Silysia Chemical Ltd., organic silicon compound-modified silica particles with an average primary particle size of 3.9 μm and a moisture absorption rate of 1.5%.
(Note 23) ACEMATT 3300: Product name, manufactured by Evonik Degussa, dimethylpolysiloxane-modified silica particles with an average primary particle size of 7 μm and a moisture absorption rate of 3.0%.
(Note 24) SYLPHOBIC 4004: Product name, manufactured by Fuji Silysia Chemical Ltd., organic silicon compound-modified silica particles having an average primary particle size of 8.0 μm and a moisture absorption rate of 2.0%.

(Note 25) DISPARLON PF-911: Product name, manufactured by Kusumoto Kasei Co., Ltd., rheology control agent, dispersible polyolefin oxide, 10% by mass of active ingredient, solvent: alkylcyclohexane / ethyl acetate mixed solvent, density (20 ° C.): 0. 84g / cm ³ ,
(Note 26) DISPARLON PFA-231: Product name, manufactured by Kusumoto Kasei Co., Ltd., rheology control agent, fatty acid amide paste, solid content 20% by mass, solvent: a mixture of alkylcyclohexane / ethanol / isopropyl alcohol.

(Note 27) BYK-066N: Product name, manufactured by BIC Chemie, silicone defoamer, solid content 0.7% by mass, solvent: ketone solvent,
(Note 28) DISPARLON LAP-20: Product name, manufactured by Kusumoto Kasei Co., Ltd., acrylic defoamer, solid content 20% by mass, solvent: ester solvent, density (20 ° C): 0.899 g / cm ³
(Note 29) DISPARLON UVX-189: Product name, manufactured by Kusumoto Kasei Co., Ltd., vinyl-based defoamer, solid content 100% (useless agent), density (20 ° C): 0.864 g / cm ³
(Note 30) Surfinol DF110D: Product name, manufactured by Nisshin Kagaku Kogyo Co., Ltd., an acetylene glycol-based antifoaming agent.

(Note 31) TIPAQUE CR-95: Product name, manufactured by Ishihara Sangyo Co., Ltd., titanium white, coloring component,
(Note 32) KAOLIN HA-90T: Product name, SHANXI JINYANG CALCINED KAOLIN, calcined kaolin, extender pigment.

(Note 33) Sumijoule N3300: Product name, Nurate form of hexamethylene diisocyanate (abbreviation: HDI nurate) Solid content 100%, NCO content = 21.8%, viscosity 3,000 mPa · sec / 25 ° C, Sumi Made by Kabayer Urethane Co., Ltd. (Note 34) Sumijuru N3600: Product name, manufactured by Sumika Bayer Urethane Co., Ltd.,
Hexamethylene diisocyanate nurate (abbreviation: HDI nurate) Solid content 100%, NCO content = 23.0%, viscosity 1,200 mPa · sec / 25 ° C,
(Note 35) Duranate TLA-100: Product name, Asahi Kasei Chemicals, hexamethylene diisocyanate nurate, solid content 100%, NCO content = 23.4%, viscosity 500 mPa · sec / 25 ° C.

<Performance evaluation>
(Note 36) Pot life (pot life):
All the components of each of the initial coating compositions obtained in the above Examples and Comparative Examples were uniformly mixed, left at 20 ° C. or 40 ° C. to measure the time until gelation was performed, and evaluated according to the following criteria. The results are shown in Tables 1-6.

S: 30 minutes or more A: 20 minutes or more and less than 30 minutes B: 10 minutes or more and less than 20 minutes C: 5 minutes or more and less than 10 minutes D: Less than 5 minutes.

(Test Examples 73 to 144 and Comparative Test Examples 13 to 20)
Each coating composition before adding the curing agent is placed in a sealed container, sealed with nitrogen, stored at 40 ° C. for 10 days, and then the curing agent is added to uniformly mix all the components to prepare the test plate below. A painted plate was created according to the procedure. These coated plates were subjected to the test described later. The evaluation results are shown in Table 7 or 8.

(Test Example 145)
Paint composition No. before adding the curing agent. The test was carried out except that 55 was placed in a sealed container, filled with nitrogen, stored at 40 ° C. for 10 days, and then a curing agent was added to uniformly mix all the components to make the base material 3 (aluminum plate). A painted plate was prepared in the same manner as in Example 73. This coated plate was subjected to the test described later. Table 8 shows the evaluation results.

(Test Examples 146-150)
Paint composition No. before adding the curing agent. 55 is placed in a sealed container, filled with nitrogen, stored at 40 ° C. for 10 days, and then a curing agent is added to uniformly mix all the components, except that the dry film thickness and coating method are as shown in Table 8. , A coated plate was prepared in the same manner as in Test Example 73. These coated plates were subjected to the test described later. Table 8 shows the evaluation results.

<How to make a painted plate>
Each coating composition was coated on the base material 1 with an airless spray so as to have a dry film thickness of 150 μm, and then dried under the following drying / curing condition 1 to prepare a coated plate. These test plates were subjected to the test described later. The drying / curing conditions 1 shown in Table 7 or Table 6 and the base materials used in the preparation of each test plate are shown below.

Drying / curing condition 1 indicates that the product is dried by leaving it at 23 ° C. and 50% relative humidity (RH) for 7 days.

As the base material 1, "SPCC-SB" (manufactured by Nippon Test Panel Co., Ltd., trade name, mild steel plate, thickness 0.8 mm) was used, and the surface thereof was lightly polished with water resistant paper # 240.

As the base material 2, the following "FRP + gel coat" was used as the base material.

Epicoat 828 (product name, manufactured by Japan Epoxy Resin Co., Ltd., bisphenol A type epoxy resin, solid content 100%) 82 parts, Seika Cure-S (product name, manufactured by Wakayama Seika Co., Ltd., diaminodiphenyl sulfone, solid content 100) %) 6 parts, phenyldimethylurea (average particle size 50 μm, solid content 100%) 5.0 parts, dicyandiamide (average particle size 7 μm) 7 parts, mix until uniform, epoxy resin composition for matrix resin I got something.

This epoxy resin composition was uniformly applied on a release paper with a roll coater so as to have a coating amount of ^{30 g / m 2 to form a resin layer.} Both sides of 125 g / m ² of glass fiber were sandwiched between the resin layers and heated with a roller under the conditions of 100 ° C. and 2 kg / cm ² to obtain a prepreg. 16 sheets of these prepregs were laminated so that the fiber directions were alternately orthogonal to each other, and ^{a pressure of 10 kg / cm 2} was applied for 15 minutes while heating at 130 ° C. with a mold to obtain a glass fiber reinforced plastic prepreg.

16 prepregs were laminated and installed in a mold so that the fiber directions were alternately orthogonal to each other, and the gap between the prepreg and the mold was set to 500 μm. A glass fiber reinforced plastic (FRP + gel coat) in which a gel coat layer was laminated was obtained by injecting a gel coat material having the following composition between a mold and a prepreg and then ^{applying a pressure of 10 kg / cm 2 for 15 minutes while heating at 130 ° C.} ..

[Gel coating material]
50 copies of castor oil,
Epicoat 828 (Product name, Epicoat is a registered trademark, bisphenol A type epoxy resin, manufactured by Japan Epoxy Resin Co., Ltd.) 30 copies,
NN Kaolin Clay (product name, clay, manufactured by Takehara Chemical Co., Ltd.) 50 copies,
After mixing and stirring until uniform
Twenty parts of diphenylmethane diisocyanate was added, and the mixture was further mixed and stirred until uniform.

An aluminum plate was used as the base material 3.

(Note 37) Storage stability:
Each paint composition before adding the curing agent is placed in a sealed container, sealed with nitrogen, stored at 40 ° C. for 10 days, and then the curing agent is added to uniformly mix all the components to evaluate the sagging resistance of the paint. bottom. Further, in the curability (curing rate) of the obtained coating plate after coating with an airless spray so as to have a dry film thickness of 150 μm using each coating composition after storage, and in the coating film appearance evaluation test after curing, The evaluation was performed by leaving each of them in two environments of 23 ° C. and 50% relative humidity (RH) or 23 ° C. and 90% relative humidity (RH). The evaluation results are shown in Table 7 or 8. Regarding the various coating film physical properties (bending resistance, impact resistance, water resistance, and chemical resistance) of the coating film obtained from each coating composition after storage, the coated plate is prepared by the method described in the method for producing the coated plate. It was prepared and the physical characteristics of various coating films were evaluated.

<Curing property (curing rate)>
A curing agent is added to each coating composition after storage on the base material 1 cut into a size of 95 mm × 150 mm, all the components are uniformly mixed, and the painted plate immediately after painting is allowed to stand on the spot for 5 minutes. Then, it was allowed to stand for a certain period of time in an environment of 23 ° C. and a relative humidity of 50% to form a coating film. The test was conducted in accordance with ISO 9117-5 "Paints and varnishes-Drying tests-Part 5: Modified Bandow-Wolff test". Drying level 7 is the strictest condition in 7 stages of drying degrees 1 to 7, and is a state in which no trace is left on the coating film surface by applying a load corresponding to ^{5 kg / cm 2.} The time required to reach the degree of dryness 7 was measured and evaluated according to the following criteria.

SS: less than 4 hours,
S: 4 hours or more and less than 5 hours,
A: 5 hours or more and less than 6 hours,
B: 6 hours or more and less than 7 hours,
C: 7 hours or more and less than 9 hours,
D: The degree of dryness level 7 is not reached even after drying for 9 hours or more.

Similarly, the evaluation was made in an environment of 23 ° C. and 90% relative humidity (RH). The evaluation results are shown in Table 7 or Table 8.

<Appearance [moisture stability]>
The appearance of the coating film after reaching the degree of dryness 7 is visually and microscopically observed within a range of 10 cm × 10 cm from the center of the coated plate, and evaluated according to the following criteria based on the presence / absence and size of foam marks and the amount thereof. bottom.

SSS: Almost no foam marks (less than 5),
SS: 5 or more and less than 10 ultrafine bubble traces (bubble trace diameter less than 1.0 μm) are observed.
S: Less than 10 fine bubble traces (bubble trace diameter 1.0 or more and less than 10 μm) are observed.
A: Fine bubble traces (bubble trace diameter 1.0 or more and less than 10 μm) are observed to be 10 or more and less than 100.
B: Less than 10 medium bubble marks (foam marks diameter of 10 μm or more and less than 1 mm) are observed.
C: Medium bubble traces (foam trace diameter 10 μm or more and less than 1 mm) are observed 10 or more and less than 100.
D: There are 5 or more bubble marks (bubble marks with a diameter of 1 mm or more) having a size that can be visually recognized.

(Note 37) Flex resistance (cylindrical mandrel method):
A curing agent is added to each coating composition after storage on the base material 1, all the components are uniformly mixed, coated so as to have a dry film thickness of 150 μm, and a test plate dried under the above-mentioned drying condition 1 is used. , JIS K5600 5-1 was measured.

The elongation rate of the coating film was calculated by the following formula based on the diameter of the mandrel in which cracks and cracks were generated in the coating film when the diameter of the mandrel was varied from 3 mm to 30 mm. The measurement was performed after the test plate was allowed to stand in an environment of −50 ° C. for 1 hour.

Elongation rate (%) = (steel plate thickness mm + dry film thickness mm) / (mandrel diameter with cracks and cracks) x 100
From the calculated growth rate, it was evaluated according to the following evaluation criteria. X indicates that the coating film does not stretch when bent and cracks and cracks occur.

SS: Growth rate is 7% or more S: Growth rate is 5% or more and less than 7% A: Growth rate is 3% or more and less than 5% B: Growth rate is 2% or more and 3% Less than C: Elongation rate is 0.5% or more and less than 2% D: Elongation rate is less than 0.5%.

(Note 38) Impact resistance (chipping property):
The coating composition after each storage was applied to the base material 2 so as to have a dry film thickness of 150 μm, and the coating composition was applied so as to have a dry film thickness of 150 μm, and a test plate dried under the drying condition 1 was prepared. The obtained test plate was installed on the sample holding table of the stepping stone tester "JA-400" (trade name, manufactured by Suga Test Instruments Co., Ltd., chipping resistance tester), and at -20 ° C, from a distance of 30 cm to 0. With compressed air of .392 MPa (4 kgf / cm ² ), 50 g of granite crushed stone having a particle size of 7 was made to collide with the test plate at an angle of 45 degrees. After that, the obtained test plate is washed with water, dried, a cloth adhesive tape (manufactured by Nichiban Co., Ltd.) is attached to the coated surface, and after peeling off, the degree of scratches on the coating film is visually observed. Then, it was evaluated according to the following criteria.

S: The size of the scratch is extremely small and the base is not exposed.
A: The size of the scratch is small and the base is not exposed.
B: The size of the scratch is large, but the base is not exposed. C: The size of the scratch is small, but the base is exposed.
D: The size of the scratches is quite large, and the base is also largely exposed.

(Note 39) Water resistance:
The coating composition after each storage is applied to the base material 2 so as to have a dry film thickness of 150 μm, the coating composition after each storage is applied so as to have a dry film thickness of 150 μm, and the coating composition is applied so as to have a dry film thickness of 150 μm. , A test plate dried under the drying condition 1 was prepared. After immersing each test plate in warm water at 40 ° C. for 30 days, the appearance and adhesiveness of the tested plate washed with water were evaluated according to the following criteria.

<Appearance [after water resistance test]>
SS: No change in appearance with respect to the coating film before the test S: Slight glossiness is seen with respect to the coating film before the test, but there is no problem when it is made into a product A: Before the test Slightly glossy and very fine blisters are seen on the coating film, but recovery is seen over time, and there is no problem when it is made into a product. Level B: Slightly glossy on the coating film before the test. Very fine blisters can be seen, but very fine blisters can be seen, and blisters can be seen without recovery.

C: Slight gloss, blistering or discoloration is observed on the coating film before the test D: Significant gloss, blistering or discoloration is observed on the coating film before the test.

(Note 41) Chemical resistance:
Each of the paint compositions after storage is applied to the base material 2 so as to have a dry film thickness of 150 μm, each of the paint compositions after storage is applied so as to have a dry film thickness of 150 μm, and is applied so as to have a dry film thickness of 150 μm. , A test plate dried under the drying condition 1 was prepared. Each test plate was immersed in a 10% sodium hydroxide solution at 20 ° C. for 10 days, and then the appearance of the test plate washed with water was evaluated according to the same criteria as the water resistance.

(Note 42) Sauce resistance:
Each coating composition after storage is coated on the base material 2 by varying the dry film thickness with an airless spray, and the coating plate is held at an angle of 60 ° with respect to the horizontal at 20 ° C. and a relative humidity of 90%. It was dried and cured in the environment. The limit film thickness at which sagging occurs was visually evaluated.

S: 250 μm or more A: 200 μm or more and less than 250 μm C: 150 μm or more and less than 200 μm D: Less than 150 μm.

Claims (10)

A coating composition containing a polyol (A), a polyisocyanate compound (B), a curing catalyst (C), and a carboxylic acid (D) having 8 or more carbon atoms, wherein the polyol (A) has 8 or more carbon atoms. It contains a polyol (A1) having a constituent unit derived from a fatty acid, the component (C) contains a (C1) bismuth compound, and the content of the component (D) is the solid content of the polyol (A). A water-based coating material or an organic solvent-type coating composition, which is in the range of 0.1 to 10 parts by mass with reference to 100 parts by mass. The coating composition according to claim 1, wherein the component (A1) is a polyol (A1') having a constituent unit derived from a fatty acid having 8 or more carbon atoms and having a primary hydroxyl group. Claim 1 or claim that the polyol (A) contains at least one polyol (A2) selected from the group consisting of polycaprolactone diol, polycaprolactone triol, polycaprolactone tetraol, polycarbonate diol, and polyacrylate polyol. Item 2. The coating composition according to Item 2. Any of claims 1 to 3 in which the content of the component (C1) of the component (C) is in the range of 0.005 to 4 parts by mass based on 100 parts by mass of the solid content of the polyol (A). The coating composition according to item 1. The coating composition according to any one of claims 1 to 4, further containing an N-substituted imidazole compound (C2) as the component (C). The coating composition according to claim 5, wherein the content of (C2) in the component (C) is in the range of 0.005 to 8 parts by mass based on 100 parts by mass of the solid content of the polyol (A). .. The coating composition according to any one of claims 1 to 6, wherein the component (D) is at least one selected from neodecanoic acid, lauric acid and tridecanoic acid. The coating composition according to any one of claims 1 to 7, further comprising hydrophobic silica particles (E) having an average primary particle diameter of 5 to 30 μm. The coating composition according to any one of claims 1 to 8, further comprising at least one antifoaming agent (F) selected from acrylic, vinyl ether, and acetylene glycol-based polymers. A coating film forming method for forming a coating film by coating an object to be coated with the coating composition according to any one of claims 1 to 9.