Coating material composition

Abstract

Provided is a coating material composition which exhibits good storage stability and can be cured in a short time. This coating material composition contains a hydroxyl group-containing resin (A), an amino resin (B), a covalent bonding block type acid catalyst (C) and a phosphoric acid-modified epoxy resin (D). Relative to a total of 100 parts by mass of the solid resin content of the hydroxyl group-containing resin (A) and the solid resin content of the amino resin (B), the content of the hydroxyl group-containing resin (A) is 60-90 parts by mass, the content of the amino resin (B) is 10-40 parts by mass, the content of an acid catalyst part of the covalent bonding block type acid catalyst (C) is 1-10 parts by mass, and the content of the solid content of the phosphoric acid-modified epoxy resin (D) is 1-10 parts by mass.

Description

TECHNICAL FIELD

[0001] The present invention relates to a coating composition. BACKGROUND OF THE INVENTION

[0002] In a wide range of industrial products such as home electric appliances, electronic devices, decorations, furniture, and building materials, a coating film is commonly formed by applying a coating composition on the surfaces and the like of the products and the parts for the purpose of protection, decoration, and the like.

[0003] Coating compositions include a two-pack type comprising a main agent and a crosslinking agent, and a one-pack type in which a main agent and a crosslinking agent are mixed in advance in a stable state. In the two-pack type, it is comperaratively easy to achieve both the storage stability of the coating composition and the physical properties of a resulting coating film. However, the two-pack type has a problem in handling and coating workability, such as that a user needs to accurately mix a main agent and a crosslinking agent in a prescribed ratio at a coating site and sufficiently stir them, and that there is a limitation on the usable time. A one-pack coating composition is hence demanded.

[0004] Meanwhile, in recent years, shortening of a coating process has been required from the viewpoint of energy saving and reduction of carbon dioxide emission. 2021347006   28 Aug 2026 For example, JP-A-2020-100740 (Patent Literature 1) describes an invention relating to a precoated metal sheet (also referred to as "PCM"), which is a coated steel sheet in which a cold-rolled steel sheet or a plated steel sheet as a substrate is coated. Commonly, coating is applied onto a surface of a steel sheet, then a coating film is formed through heating step (baking step) at a peak temperature of the steel sheet, which is an article to be coated, (this temperature is also referred to as peak metal temperature “PMT”) of 200 to 270°C for 30 to 60 seconds to form a coating film, and then the resulting precoated metal sheet is processed into a required product. In this case, as a baking furnace to be used for baking, a hot air furnace using a gas or the like as a means for heating is commonly used. In this case, however, it is necessary to constantly maintain an ambient temperature at 300°C or higher, and reduction in energy cost is demanded. CITATIONS LIST PATENT LITERATURE

[0005] Patent Literature 1: JP-A-2020-100740 SUMMARY OF INVENTION

[0006] Instead of the hot air type furnace as described above, an induction heater (also referred to as "IH") type furnace has been developed and is beginning to be introduced in companies. As a result, the furnace length is shortened, so that the manufacturing space can be reduced, and the PMT can be raised to 220°C in a short time. On the other hand, since the furnace length of the IH type furnace as described 2021347006   28 Aug 2026 above is shortened, the curing time of a coating composition is also required to be shortened. In order to shorten the curing time of a one-pack coating composition, it is necessary to increase the curing reaction rate using a large amount of an acid catalyst. However, when the coating composition contains a large amount of an acid catalyst, there is a problem in storage stability of the coating composition. As described above, it has been difficult to obtain a coating composition which has good storage stability and can be cured in a short time.

[0007] The present invention seeks to provide a coating composition that has good storage stability and can be cured in a short time. Further, the present invention seeks to provide a method for producing a coating film by heating for a short time using the coating composition. The present invention also seeks to provide a method for producing a precoated metal sheet by heating for a short time using the coating composition.

[0008] The present invention provides the following embodiments [1] to

[13] . [1]     A coating composition comprising a hydroxyl group-containing resin (A), an amino resin (B), a covalently bonded blocked acid catalyst (C), a phosphoric acid-modified epoxy resin (D), and an alkanolamine (E), wherein based on 100 parts by mass of a total of a resin solid content of the hydroxyl group-containing resin (A) and a resin solid content of the amino resin (B), 60 to 90 parts by mass of the hydroxyl group-containing resin (A), 10 to 40 parts by mass of the amino resin (B), 1 to 10 parts by mass of an acid catalyst moiety of the covalently bonded 2021347006   28 Aug 2026 blocked acid catalyst (C), and 1 to 10 parts by mass of a solid component of the phosphoric acid-modified epoxy resin (D) are contained. [2]     The coating composition according to [1], wherein a number-average molecular weight of the phosphoric acid-modified epoxy resin (D) is in a range of 460 to 4,000. [3]     The coating composition according to [1] or [2], wherein the covalently bonded blocked acid catalyst (C) is a catalyst in which an aromatic sulfonic acid is blocked by a compound having a glycidyl group. [4]     The coating composition according to [3], wherein in the covalently bonded blocked acid catalyst (C), the compound having a glycidyl group is an epoxy resin having two or more glycidyl groups in a molecule or a glycidyl ether compound having one glycidyl group in a molecule. [5]     The coating composition according to [4], wherein in the covalently bonded blocked acid catalyst (C), a number-average molecular weight of the epoxy resin having two or more glycidyl groups is in a range of 2,000 to 7,000. [6]     The coating composition according to [5], wherein in the covalently bonded blocked acid catalyst (C), a molecular weight of the glycidyl ether compound having one glycidyl group in a molecule is in a range of 140 to 200. [7]     The coating composition according to any one of [1] to [6], wherein the hydroxyl group-containing resin (A) is a polyester resin and a number-average molecular weight of the hydroxyl group-containing resin (A) is in a range of 1,500 to 5,000 and a hydroxyl value is in a range of 40 to 100 mg KOH / g. [8]     The coating composition according to any one of [1] to [7], wherein the amino resin (B) comprises a melamine resin. 2021347006   28 Aug 2026 [9]     The coating composition according to any one of [1] to [8], wherein the alkanolamine (E) comprises two or more alkanol groups in a molecule.

[10] The coating composition according to any one of [1] to [9], wherein a content of the alkanolamine (E) is 1.0 to 4.0 parts by mass based on 100 parts by mass of the total of the resin solid content of the hydroxyl group-containing resin (A) and the resin solid content of the amino resin (B).

[11] A method for producing a coating film, comprising: a step of applying the coating composition according to any one of [1] to

[10] to an article to be coated to form an applied film; and a step of drying and / or curing the applied film under a condition in which a peak temperature of the article is 180°C to 270°C and a drying and / or curing time is 1 to 10 seconds.

[12] A method for producing a precoated metal sheet, comprising: a step of applying the coating composition according to any one of [1] to

[10] to at least one surface of a metal sheet to form an applied film such that a film thickness after curing is 5 to 25 urn; and a step of drying and / or curing the applied film under a condition in which a peak temperature of the metal sheet is 180°C to 270°C and a drying and / or curing time is 1 to 10 seconds.

[0009] The coating composition of the present invention exhibits good storage stability, and a curing reaction thereof can sufficiently proceed even by heating for a short time. Furthermore, by the method for producing a coating film of the present invention, a coating film can be produced by heating for a short time. 2021347006   28 Aug 2026 In addition, by the method for producing a precoated metal sheet of the present invention, a precoated metal sheet can be produced by heating for a short time. DESCRIPTION OF EMBODIMENTS

[0010] [Coating composition] The coating composition of the present disclosure will be described.

[0011] The coating composition of the present disclosure comprises a hydroxyl group-containing resin (A), an amino resin (B), a covalently bonded blocked acid catalyst (C), a phosphoric acid-modified epoxy resin (D), and an alkanolamine (E), wherein based on 100 parts by mass of a total of a resin solid content of the hydroxyl group-containing resin (A) and a resin solid content of the amino resin (B), 60 to 90 parts by mass of the hydroxyl group-containing resin (A), 10 to 40 parts by mass of the amino resin (B), 1 to 10 parts by mass of an acid catalyst moiety of the covalently bonded blocked acid catalyst (C), and 1 to 10 parts by mass of a solid component of the phosphoric acid-modified epoxy resin (D) are contained.

[0012] <Hydroxyl group-containing resin (A)> The hydroxyl group-containing resin (A) is a resin having a hydroxyl group in a molecular structure thereof. The hydroxyl group-containing resin (A) reacts with the amino resin (B) as a curing agent to form a coating film. 2021347006   28 Aug 2026 Examples of the hydroxyl group-containing resin (A) include a polyester resin, an epoxy resin, and an acrylic resin, and a polyester resin is preferable.

[0013] (Polyester resin) The polyester resin is not particularly limited as long as it is a polyester resin commonly used for coating materials. Unless otherwise specified in the present disclosure, when simply described as “polyester resin”, it means that the polyester resin comprises at least one species selected from the group consisting of polyester resin and modified products of polyester resin.

[0014] The hydroxyl value of the hydroxyl group-containing polyester resin is preferably 40 to 100 mg KOH / g, and more preferably 60 to 100 mg KOH / g. When the hydroxyl value of the polyester resin is in the above range, the reaction with the amino resin (B) as a curing agent proceeds well. When the coating composition contains such a polyester resin, there is an advantage that a resulting coating film is high in solvent resistance, folding processability, processing adhesive property, and chemical resistance. In the present disclosure, the hydroxyl value represents a solid hydroxyl value and is a value measured by the method described in JIS K 0070.

[0015] The number-average molecular weight of the polyester resin is preferably 1,500 to 5,000, more preferably 2,000 to 4,500, and particularly preferably 2,000 to 4,000. When the number-average molecular weight of the polyester resin is in the above range, the curing reaction with the amino resin (B) sufficiently proceeds and a coating film having high solvent resistance and chemical resistance can be formed. 2021347006   28 Aug 2026 Further, it is possible to inhibit the crosslink density of the coating film from becoming excessively high, and it is possible to form a coating film having a sufficient elongation rate and, for example, it is possible to form a coating film having sufficient folding processability and processing adhesive property. Furthermore, the coating composition of the present disclosure has an appropriate viscosity and is good in handleability. In the present disclosure, the number-average molecular weight is a polystyrene-equivalent value determined by gel permeation chromatography (GPC).

[0016] The glass transition temperature (Tg) of the polyester resin is preferably -35°C or higher and 110°C or lower, for example, -30°C or higher and 80°C or lower, and may be -30°C or higher and 60°C or lower. When the glass transition temperature (Tg) of the polyester resin is in the above range, the moisture permeability of a coating film is not excessively high and the coating film has sufficient moisture resistance and chemical resistance. In the present disclosure, the glass transition temperature (Tg) can be measured using, for example, a thermal analyzer (TMA7100 (manufactured by Hitachi High-Tech Science Corporation) or the like).

[0017] The acid value of the polyester resin is, for example, 0.1 mg KOH / g or more and 30 mg KOH / g or less, or 0.2 mg KOH / g or more and 30 mg KOH / g or less, and may be 0.3 mg KOH / g or more and 30 mg KOH / g or less. When the acid value of the polyester resin is in the above range, for example, hydrolysis resistance can be improved, and a coating film having moisture resistance and chemical resistance can be formed. 2021347006   28 Aug 2026 In the present disclosure, the acid value represents a solid acid value, and is a value measured by the method described in JIS K 0070.

[0018] The polyester resin can be obtained by polycondensation of a polyhydric alcohol and a polybasic acid. Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, neopentyl glycol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol or 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, hydrogenated bisphenol A, hydroxyalkylated bisphenol A, 1,4-cyclohexanedimethanol, 2,2-dimethyl-3-hydroxypropyl-2,2-dimethyl-3-hydroxypropionate (BASHPN), N,N-bis-(2-hydroxyethyl)dimethylhydantoin, polycaprolactone polyol, glycerin, sorbitol, annitol, trimethylolethane, trimethylolpropane, trimethylolbutane, hexanetriol, pentaerythritol, dipentaerythritol, and tris(2-hydroxyethyl)isocyanurate. As the polyhydric alcohol, only one species may be used, or two or more species may be used in combination.

[0019] Examples of the polybasic acid include phthalic acid, phthalic anhydride, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, methyltetraphthalic acid, methyltetrahydrophthalic anhydride, hymic anhydride, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic dianhydride, isophthalic acid, terephthalic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, adipic acid, azelaic acid, sebacic acid, succinic acid, succinic anhydride, lactic acid, dodecenylsuccinic acid, dodecenylsuccinic anhydride, cyclohexane-1,4-dicarboxylic acid, and endic anhydride. As the polybasic acid, only one species may be used, or two or more species may be used in combination.

[0020] 2021347006   28 Aug 2026 Examples of the modified products of polyester resin include modified polyester resins such as urethane-modified polyester resins, epoxy-modified polyester resins, acrylic-modified polyester resins, and silicone-modified polyester resins. For example, the urethane-modified polyester resin is a resin having polyester as its main chain and urethane-modified by modifying the ends thereof with isocyanate. For example, the silicone-modified polyester resin can be prepared by reacting a polyester resin with an organic silicone (for example, an organic silicone having an -Si-OCH3 group and / or an Si-OH group as a functional group and having a number-average molecular weight of about 300 to about 1,000). The amount of the organic silicone used is usually about 5 to about 50 parts by mass per 100 parts by mass of the polyester resin. For example, the urethane-modified polyester resin can be prepared by reacting the polyester resin with a polyisocyanate compound.

[0021] As the polyester resin, a commercially available product may also be used, and examples thereof include DYNAPOL LH820, DYNAPOL LH826, and DYNAPOL LH727 (all manufactured by Evonik Industries AG), ETERKYD 5084-R-60-6E, ETERKYD 3103-X-70, ETERKYD 50528-R-70, and ETERKYD 5055R-65-3 (all manufactured by Eternal Materials Co., Ltd.), BECKOLITE M-6902-50 (manufactured by DIC Corporation), and SYNOLAC 9605 (manufactured by ARKEMA).

[0022] (Epoxy resin) The epoxy resin is not particularly limited as long as it is an epoxy resin commonly used for coating materials. Unless otherwise specified in the present disclosure, when simply described as “epoxy resin”, it means that the epoxy resin comprises at least one species selected from the group consisting of epoxy resin and 2021347006   28 Aug 2026 modified products of epoxy resin.

[0023] The hydroxyl value of the epoxy resin is preferably 40 to 200 mg KOH / g, and more preferably 60 to 180 mg KOH / g. When the hydroxyl value of the epoxy resin is in the above range, the reaction with the amino resin (B) as a curing agent proceeds well. When the coating composition contains such an epoxy resin, there is an advantage that a resulting coating film exhibits high solvent resistance, sufficient folding processability, processing adhesive property, and chemical resistance.

[0024] The number-average molecular weight of the epoxy resin is preferably 1,500 to 5,000, and more preferably 2,000 to 4,000. When the number-average molecular weight of the epoxy resin is in the above range, a curing reaction with the amino resin (B) to be described later sufficiently proceeds, so that a coating film having good coating film appearance can be formed. Further, it is possible to inhibit the crosslink density of the coating film from becoming excessively high, and it is possible to form a coating film having a sufficient elongation rate and, for example, it is possible to form a coating film having sufficient folding processability and processing adhesive property. Furthermore, the coating composition of the present disclosure has an appropriate viscosity and is good in handleability.

[0025] The glass transition temperature (Tg) of the epoxy resin may be 120°C or lower, and may be 115°C or lower. For example, the glass transition temperature (Tg) of the epoxy resin may be 110°C or lower. In one embodiment, the glass transition temperature (Tg) of the epoxy resin is 50°C or higher and may be 55°C or higher. For example, the glass transition temperature (Tg) of the epoxy resin may be in a range of 2021347006   28 Aug 2026 50°C or higher and 120°C or lower. When the glass transition temperature (Tg) of the epoxy resin is in the above range, the moisture permeability of a coating film is not excessively high and the coating film has sufficient moisture resistance and chemical resistance.

[0026] The epoxy resin may be a hydroxyl group-containing epoxy resin (including a modified hydroxyl group-containing epoxy resin). Examples of the epoxy resin include a resin prepared by condensing epichlorohydrin and bisphenol to a high molecular weight in the presence of a catalyst such as an alkaline catalyst as necessary; bisphenol type epoxy resins such as bisphenol A type and bisphenol F type; and novolak type epoxy resins. Examples of the modified products of epoxy resin include modified epoxy resins such as acrylic-modified epoxy resins, urethane-modified epoxy resins, and amine-modified epoxy resins. For example, the acrylic-modified epoxy resin can be prepared by reacting the bisphenol type epoxy resin described above or the novolac type epoxy resin described above with a polymerizable unsaturated monomer component containing acrylic acid, methacrylic acid, or the like. For example, the urethane-modified epoxy resin can be prepared by reacting the bisphenol type epoxy resin described above or the novolak type epoxy resin described above with a polyisocyanate compound. In one embodiment, the modified product of the epoxy resin is a resin other than phosphoric acid-modified epoxy resins and sulfonic acid-modified epoxy resins.

[0027] Commercially available products may also be used as the epoxy resin, and examples thereof include jER825, jER828, jER835, jER1004, jER1007, jER1010, 2021347006   28 Aug 2026 jER1255HX30, jER YX8100BH30 (all are of bisphenol A type, manufactured by Mitsubishi Chemical Corporation), and jER1009 F (Bisphenol F type, manufactured by Mitsubishi Chemical Corporation).

[0028] (Acrylic resin) The acrylic resin is not particularly limited as long as it is an acrylic resin commonly used for coating materials. Unless otherwise specified in the present disclosure, when simply described as “acrylic resin”, it means that it comprises at least one species selected from the group consisting of acrylic resin and modified products of acrylic resin.

[0029] The hydroxyl value of the acrylic resin is preferably 40 to 100 mg KOH / g, and more preferably 60 to 100 mg KOH / g. When the hydroxyl value of the acrylic resin is in the above range, the reaction with the amino resin (B) as a curing agent proceeds well. When the coating composition contains such an acrylic resin, there is an advantage that a resulting coating film has high solvent resistance and chemical resistance, and sufficient folding processability and processing adhesive property.

[0030] The number-average molecular weight of the acrylic resin is preferably 1,500 to 5,000, and more preferably 2,000 to 4,000. When the number-average molecular weight of the acrylic resin is in the above range, the curing reaction with the amino resin (B) sufficiently proceeds and a coating film having good coating film appearance can be formed. Further, it is possible to inhibit the crosslink density of the coating film from becoming excessively high, and it is possible to form a coating film having a sufficient elongation rate and, for example, it is possible to form a coating film having sufficient 2021347006   28 Aug 2026 folding processability. Furthermore, the coating composition of the present disclosure has an appropriate viscosity and is good in handleability.

[0031] The glass transition temperature (Tg) of the acrylic resin is preferably -35°C or higher and 110°C or lower, for example, -30°C or higher and 80°C or lower, and may be -30°C or higher and 60°C or lower. When the glass transition temperature (Tg) of the acrylic resin is in the above range, the moisture permeability of a coating film is not excessively high and the coating film has good moisture resistance and chemical resistance.

[0032] The acid value of the acrylic resin (including modified products thereof) is, for example, 0.1 mg KOH / g or more and 30 mg KOH / g or less, or 0.2 mg KOH / g or more and 30 mg KOH / g or less, and may be 0.3 mg KOH / g or more and 30 mg KOH / g or less. When the acid value of the acrylic resin is in such a range, for example, hydrolysis resistance can be improved, and a coating film having moisture resistance and chemical resistance can be formed.

[0033] Examples of the acrylic resin include acrylic resins made up of one or two or more of monomer selected from among (meth)acrylic monomers having a hydroxy group, such as hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate and N-methylolacrylamide, and lactone adducts thereof; (meth)acrylic acid; (meth)acrylic acid esters, such as alkyl (meth)acrylate; and (meth)acrylonitrile. The acrylic resin may contain, in addition to the constitutional units derived from the above-mentioned monomers, constitutional units derived from other monomers (for example, carboxy group-containing ethylenic 2021347006   28 Aug 2026 monomers such as crotonic acid, itaconic acid, fumaric acid, and maleic acid, and vinylbased monomers such as styrene). Examples of the modified products of acrylic resin include modified acrylic resins such as silicone-modified acrylic resins. For example, the silicone-modified acrylic resin can be prepared by reacting an acrylic resin with an organic silicone such as that described above. The amount of the organic silicone used is usually about 5 to about 50 parts by mass per 100 parts by mass of the acrylic resin. In the present disclosure, (meth)acrylic acid represents acrylic acid or methacrylic acid. As the acrylic resin, a commercially available product may also be used, and examples thereof include ACRYDIC A-608, ACRYDIC A-452, and ACRYDIC A-830 (all manufactured by DIC Corporation).

[0034] As the hydroxyl group-containing resin (A), only one species may be used, or two or more species may be used in combination.

[0035] <Amino resin (B)> The amino resin (B) is a resin that reacts with the hydroxyl group-containing resin (A) and the phosphoric acid-modified epoxy resin (D) to form a cured coating film. The amino resin (B) is superior in curing reactivity with the hydroxyl group-containing resin (A) and the like and can afford a coating film having good appearance and moisture resistance.

[0036] Examples of the amino resin include melamine resin, urea resin, and benzoguanamine, and melamine resin and urea resin are preferable. Especially from the viewpoint of weather resistance, the amino resin preferably contains melamine resin, 2021347006   28 Aug 2026 and more preferably is melamine resin.

[0037] “Melamine resin” generally means a thermally curable resin synthesized from melamine and aldehyde, and has three reactive functional groups -NX1X2 in one triazine nucleus molecule. Examples of the melamine resin include the following four types: afully alkylated type containing -N(CH2OR)2 [R represents an alkyl group having 1 to 8 carbon atoms, the same applies hereinafter] as a reactive functional group; a methylol group type containing -N(CH2OR)(CH2OH) as a reactive functional group; an imino group type containing -N(CH2OR)(H) as a reactive functional group; a methylol / imino group type containing -N(CH2OR)(CH2OH) and -N(CH2OR)(H) or containing -N(CH2OH)(H) as reactive functional groups. In the present invention, it is preferable to use a fully alkylated melamine resin among the melamine resins described above, and examples of such a resin include methylated melamine resin, butylated melamine resin, and isobutylated melamine resin. As the melamine resin, a commercially available product may also be used, and examples thereof include CYMEL 303, CYMEL 325, CYMEL 350, CYMEL 370, MYCOAT 715 (all are methylated melamine resins, manufactured by Allnex Japan Inc.), CYMEL 202, CYMEL 235, CYMEL 254, CYMEL 1123, CYMEL 1128, CYMEL 1170, MYCOAT 212, (all are methylated-butylated mixed melamine resins, manufactured by Allnex Japan Inc.), SUMIMAL M-40S (methylated melamine resin, manufactured by Sumitomo Chemical Co., Ltd.), AMIDIR J-820-60, and AMIDIR L-127-60 (all are butylated melamine resins, manufactured by DIC Corporation).

[0038] As the amino resin (B), only one species may be used, or two or more species 2021347006   28 Aug 2026 may be used in combination.

[0039] In one embodiment, a polyester resin is used as the hydroxyl group-containing resin (A) and a melamine resin is used as the amino resin (B).

[0040] The coating composition of the present disclosure contains 60 to 90 parts by mass of the hydroxyl group-containing resin (A) and 10 to 40 parts by mass of the amino resin (B), preferably 70 to 80 parts by mass of the hydroxyl group-containing resin (A) and 20 to 30 parts by mass of the amino resin (B), based on 100 parts by mass of the total of the resin solid content of the hydroxyl group-containing resin (A) and the resin solid content of the amino resin (B). When the hydroxyl group-containing resin (A) and the amino resin (B) are contained in the above ranges, the curing reaction between the hydroxyl group-containing resin (A) and the amino resin (B) proceeds well. When these resins are contained in the above ranges, the appearance of a resulting coating film can be improved. In addition, the solvent resistance, folding processability, processing adhesive property, and chemical resistance of a coating film obtained from the coating composition of the present disclosure are improved.

[0041] <Covalently bonded blocked acid catalyst (C)> The covalently bonded blocked acid catalyst (C) has a structure in which an acid catalyst is blocked by a blocking agent, for example, a structure in which the acid catalyst is protected by covalently bonding the blocking agent to the acid catalyst (especially, an acid group of the acid catalyst). When the blocking agent protects the acid catalyst, the action as a curing catalyst is suppressed during storage and the storage stability of the coating composition is improved. When the blocking agent is 2021347006   28 Aug 2026 dissociated by heating or the like, the acid catalyst acts as a curing catalyst to accelerate the reaction of the hydroxyl group-containing resin (A), the amino resin (B), and the phosphoric acid-modified epoxy resin (D). In the coating composition of the present disclosure, the acid catalyst moiety of the covalently bonded blocked acid catalyst (C) is contained in an amount of 1 to 10 parts by mass, preferably 1 to 7 parts by mass, and more preferably 1 to 5 parts by mass, based on 100 parts by mass of the total of the resin solid content of the hydroxyl group-containing resin (A) and the resin solid content of the amino resin (B). When the covalently bonded blocked acid catalyst (C) is contained in the above range, the storage stability of the resulting coating composition is good, and a coating film having high solvent resistance and sufficient folding processability, processing adhesive property, and chemical resistance will be formed by curing. The acid catalyst moiety refers to, for example, a sulfonic acid when the covalently bonded blocked acid catalyst (C) has a structure in which a blocking agent is covalently bonded to a sulfonic acid.

[0042] Usually, a coating composition often contains an acid catalyst in order to increase a curing rate. However, when the content of the acid catalyst increases, the storage stability of the coating composition tends to deteriorate. When an acid catalyst not protected by a blocking agent is used as the acid catalyst or when an acid catalyst neutralized by an amine (that is, an amine blocked acid catalyst) is used, the storage stability of a resulting coating composition and the physical properties of a coating film to be formed may be deteriorated. In contrast, the coating composition of the present disclosure contains the covalently bonded blocked acid catalyst (C), and hencet the curing reaction is 2021347006   28 Aug 2026 accelerated and the storage stability is improved.

[0043] The covalently bonded blocked acid catalyst (C) preferably comprises a sulfonic acid as an acid catalyst, and the acid catalyst is more preferably a sulfonic acid. The number of sulfonic acid groups in the sulfonic acid is 1 or more per molecule, and may be, for example, 2 or less, and is particularly 1.

[0044] In one embodiment, the covalently bonded blocked acid catalyst (C) excludes a phosphate compound.

[0045] The covalently bonded blocked acid catalyst (C) is preferably one in which a blocking agent is covalently bonded to all the sulfonic acid groups of the sulfonic acid as an acid catalyst. Examples of the sulfonic acid include aliphatic sulfonic acids such as methanesulfonic acid, and aromatic sulfonic acids such as p-toluenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, and dodecylbenzenesulfonic acid. These may be used singly, or two or more of them may be used in combination. In the present disclosure, the aromatic sulfonic acid refers to a sulfonic acid having a structure in which one or more sulfonic acid groups (e.g., one or two, specifically one sulfonic acid group) are directly bonded to an aromatic ring. In the aromatic sulfonic acid, examples of the aromatic ring include a benzene ring and a naphthalene ring. In the aromatic sulfonic acid, one or more alkyl groups having 1 to 15 carbon atoms may be bonded to a carbon atom constituting an aromatic ring; more specifically, one or two alkyl groups, for example, one alkyl group may be bonded. 2021347006   28 Aug 2026

[0046] Preferably, the covalently bonded blocked acid catalyst (C) has a blocked structure in which a compound having a glycidyl group as a blocking agent is covalently bonded to a sulfonic acid as an acid catalyst. In other words, it has a structure in which a sulfonic acid (specifically, a sulfonic acid group of the sulfonic acid) is blocked with a compound having a glycidyl group (specifically, a glycidyl group of a compound having a glycidyl group).

[0047] Furthermore, the covalently bonded blocked acid catalyst (C) preferably has a structure in which an aromatic sulfonic acid is blocked with a compound having a glycidyl group. In other words, it is preferable that the sulfonic acid group of the aromatic sulfonic acid is blocked with the glycidyl group of the compound having a glycidyl group. Due to the inclusion of such a covalently bonded blocked acid catalyst (C), the stability of the coating composition during storage can be further improved, and the glycidyl group is dissociated by heating or the like, so that the curing reaction can be further accelerated.

[0048] Examples of the aromatic sulfonic acid blocked with a glycidyl group include compounds in which an aromatic sulfonic acid such as dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, paratoluenesulfonic acid, or dodecylbenzenesulfonic acid is blocked with a glycidyl group. Among them, a catalyst in which dinonylnaphthalenesulfonic acid is blocked with a glycidyl group is particularly preferable. As the aromatic sulfonic acid blocked with a glycidyl group, a commercially available product may be used, and examples thereof include Nacure 1419 (trade name, manufactured by King Industries, Ltd.). 2021347006   28 Aug 2026

[0049] In the covalently bonded blocked acid catalyst (C), the compound having a glycidyl group to be used for blocking the sulfonic acid is preferably an epoxy resin having two or more glycidyl groups in the molecule or a glycidyl ether compound having one glycidyl group in the molecule. When such a compound is used, the stability of the resulting coating composition during its storage can be further improved, and the glycidyl group is dissociated by heating or the like, so that the curing reaction can be further promoted. Hereinafter, a covalently bonded blocked acid catalyst prepared by using an epoxy resin having two or more glycidyl groups in the molecule as a blocking agent may be referred to as a covalently bonded blocked acid catalyst (C1), and a covalently bonded blocked acid catalyst prepared by using a glycidyl ether compound having one glycidyl group in the molecule as a blocking agent may be referred to as a covalently bonded blocked acid catalyst (C2).

[0050] The number of the glycidyl groups in the compound having a glycidyl group is 1 or more per molecule, and may be, for example, 5 or less, and may be 3 or less. The number-average molecular weight of the compound having a glycidyl group is preferably 100 to 10,000, and more preferably 140 to 7,000.

[0051] In one embodiment, the compound having a glycidyl group to be used for blocking the sulfonic acid is preferably an epoxy resin having two or more glycidyl groups in the molecule. The epoxy resin to be used for blocking the sulfonic acid is not particularly limited as long as it is an epoxy resin having two or more glycidyl groups in the 2021347006   28 Aug 2026 molecule. The epoxy resin may be a hydroxyl group-containing epoxy resin (including a modified hydroxyl group-containing epoxy resin). Examples of the epoxy resin include a resin prepared by condensing epichlorohydrin and bisphenol to a high molecular weight in the presence of a catalyst such as an alkaline catalyst as necessary; bisphenol type epoxy resins such as bisphenol A type and bisphenol F type; and novolak type epoxy resins, and among these, bisphenol type epoxy resins are preferable, and bisphenol A type epoxy resins are more preferable.

[0052] Examples of the modified products of epoxy resin include modified epoxy resins such as acrylic-modified epoxy resins, urethane-modified epoxy resins, and amine-modified epoxy resins. For example, taking an acrylic-modified epoxy resin as an example, it can be prepared by reacting the bisphenol type epoxy resin or the novolac type epoxy resin with a polymerizable unsaturated monomer component containing acrylic acid, methacrylic acid, or the like. Taking a urethane-modified epoxy resin as an example, it can be prepared by reacting the bisphenol type epoxy resin or the novolak type epoxy resin with a polyisocyanate compound.

[0053] In one embodiment, the modified product of the epoxy resin excludes a phosphoric acid-modified epoxy resin. As the epoxy resin, a commercially available product may be used, and examples thereof include jER825, jER828, jER834, jER1004, jER1007, jER1009, jER1010, jER1255HX30 (all are of bisphenol A type, manufactured by Mitsubishi Chemical Corporation), and jER1009F (bisphenol F type, manufactured by Mitsubishi 2021347006   28 Aug 2026 Chemical Corporation), and jER1007, jER1009, and jER1010 are preferable.

[0054] The number-average molecular weight of the epoxy resin is preferably 2,000 to 7,000. When the number-average molecular weight of the epoxy resin is in the above range, a curing reaction with the hydroxyl group-containing resin (A), the amino resin (B), and the phosphoric acid-modified epoxy resin (D) sufficiently proceeds, and a coating film having high solvent resistance and sufficient folding processability, processing adhesive property, and chemical resistance can be formed.

[0055] In one embodiment, the compound having a glycidyl group to be used for blocking the sulfonic acid is preferably a glycidyl ether compound having one glycidyl group in the molecule.

[0056] The glycidyl ether compound to be used for blocking the sulfonic acid is not particularly limited as long as it is a glycidyl ether compound having one glycidyl group in the molecule. Examples of the glycidyl ether compound include aromatic glycidyl ether compounds, aliphatic glycidyl ether compounds, and alicyclic glycidyl ether compounds. Among these, aromatic glycidyl ether compounds are preferable, and phenyl glycidyl ether is more preferable.

[0057] As the glycidyl ether compound, a commercially available product may be used, and examples thereof include phenyl glycidyl ether, o-cresyl glycidyl ether (both are aromatic glycidyl ether compounds, manufactured by Yokkaichi Chemical Co., Ltd.), DY-BP, EPOGOSEY-2EH, EPOGOSEY-LA(D), and EPOGOSEY-AN (all are 2021347006   28 Aug 2026 aliphatic glycidyl ether compounds, manufactured by Yokkaichi Chemical Co., Ltd.), and phenyl glycidyl ether are preferable.

[0058] The molecular weight of the glycidyl ether compound is preferably 140 to 200. When the molecular weight of the glycidyl ether compound is in the above range, a curing reaction with the hydroxyl group-containing resin (A), the amino resin (B), and the phosphoric acid-modified epoxy resin (D) sufficiently proceeds, and a coating film having high solvent resistance and sufficient folding processability, processing adhesive property, and chemical resistance can be formed. In the present disclosure, the molecular weight of the glycidyl ether compound is a value calculated from a molecular formula.

[0059] The covalently bonded blocked acid catalyst (C) can be formed by, for example, blocking a sulfonic acid group of a sulfonic acid with a glycidyl group of a compound having a glycidyl group (specifically, an epoxy resin having two or more glycidyl groups or a glycidyl ether compound having one glycidyl group; hereinafter, the same applies in this paragraph). Specifically, the covalently bonded blocked acid catalyst (C) can be formed by weighing a sulfonic acid and a compound having a glycidyl group in such a mass that a molar ratio of the sulfonic acid groups of the sulfonic acid to the glycidyl groups of the compound having a glycidyl group is in a range of 1:1 to 1:2, adding them to a container, and stirring them, for example, at 90°C for 120 minutes thereby blocking the sulfonic acid group with the glycidyl group. A coating composition can be formed by mixing the formed covalently bonded blocked acid catalyst (C) with the hydroxyl group-containing resin (A), the amino resin (B), the phosphoric acid-modified epoxy resin (D), and other components as necessary. 2021347006   28 Aug 2026

[0060] <Phosphoric acid-modified epoxy resin (D)> The phosphoric acid-modified epoxy resin (D) contains a phosphoric acid group [-OPO(OH)(OR1)] wherein R1 is a hydrogen atom, a phenyl group, or an alkyl group having 1 to 20 carbon atoms and is particularly preferably a hydrogen atom. As the phosphoric acid-modified epoxy resin (D), one compatible with the hydroxyl group-containing resin (A) and the amino resin (B) is used. In the coating composition of the present disclosure, a solid component of the phosphoric acid-modified epoxy resin (D) is contained in an amount of 1 to 10 parts by mass, preferably 1 to 5 parts by mass, based on 100 parts by mass of the total of the resin solid content of the hydroxyl group-containing resin (A) and the resin solid content of the amino resin (B). When the phosphoric acid-modified epoxy resin (D) is contained in the above range, a coating film having high solvent resistance and sufficient folding processability, processing adhesive property, and chemical resistance can be formed. In particular, even when the curing time is short, curing proceeds sufficiently, so that a coating film having good physical properties can be formed.

[0061] The number-average molecular weight of the phosphoric acid-modified epoxy resin (D) is preferably 400 to 6,000, and more preferably 460 to 4,000. The phosphoric acid-modified epoxy resin (D) having such a number-average molecular weight can further contribute to a formation of a coating film having high solvent resistance and sufficient folding processability, processing adhesive property, and chemical resistance.

[0062] The phosphoric acid-modified epoxy resin (D) can be obtained, for example, 2021347006   28 Aug 2026 by adding a phosphoric acid-based compound to an epoxy resin. Specifically, the phosphoric acid-modified epoxy resin (D) can be obtained by mixing the epoxy resin and the phosphoric acid-based compound in such a mass that a molar ratio of the glycidyl groups of the epoxy resin to the phosphoric acid groups of the phosphoric acidbased compound is 1:1 to 1:2, and reacting the mixture, for example, at 80°C for 120 minutes. In one embodiment, the epoxy resin comprises glycidyl groups only at both ends. In one embodiment, the phosphoric acid-modified epoxy resin (D) excludes a phosphoric acid-modified epoxy resin reacted with a sulfonic acid.

[0063] In the phosphoric acid-modified epoxy resin (D), examples of the epoxy resin include bisphenol type epoxy resins, novolac type epoxy resins, and modified epoxy resins obtained by reacting various modifiers with glycidyl groups or hydroxyl groups in these epoxy resins. Among them, bisphenol type epoxy resins are preferably used, and bisphenol A type epoxy resins are more preferably used. As the epoxy resin, a commercially available product may be used, and examples thereof include jER825, jER828, jER834, jER1004, jER1007, jER1009, jER1010, jER1255HX30 (all are of bisphenol A type, manufactured by Mitsubishi Chemical Corporation), and jER1009F (bisphenol F type, manufactured by Mitsubishi Chemical Corporation), and jER828, jER834, jER1004, jER1007, and jER1009 are preferable. The number-average molecular weight of the epoxy resin is preferably 370 to 3,800, for example, when the phosphoric acid compound for modification is phosphoric acid. 2021347006   28 Aug 2026 As the epoxy resin, an acrylic-modified epoxy resin, a polyester-modified epoxy resin, or the like may be used.

[0064] In one embodiment, in the phosphoric acid-modified epoxy resin (D), the molecular weight of the phosphoric acid-based compound is 98 to 1,200.

[0065] In the phosphoric acid-modified epoxy resin (D), the phosphoric acid-based compound is not particularly limited as long as it can introduce a phosphoric acid group into the epoxy resin, and examples thereof include orthophosphoric acid and acidic phosphoric acid esters. The acidic phosphoric acid ester refers to a structure in which one or two hydrogens among three hydrogens of phosphoric acid (O=P(OH)3) are replaced by an organic group. Examples of the organic group include an alkyl group (for example, having 1 to 24 carbon atoms), an alkyl ether group (for example, represented by R3-OR4O-, wherein R3 is an alkyl group having 1 to 5 carbon atoms, and R4 is methylene group, ethylene group, propylene group, preferably ethylene group or propylene group), and an aromatic group. Examples of the acidic phosphoric acid ester include methyl acid phosphate, butyl acid phosphate, 2-ethylhexyl acid phosphate, isodecyl acid phosphate, lauryl acid phosphate, isotridecyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, and phenyl acid phosphate.

[0066] The coating composition of the present disclosure comprises the covalently bonded blocked acid catalyst (C) and the phosphoric acid-modified epoxy resin (D) together with the hydroxyl group-containing resin (A) and the amino resin (B) as described above. When both the covalently bonded blocked acid catalyst (C) and the 2021347006   28 Aug 2026 phosphoric acid-modified epoxy resin (D) are contained, storage stability of the coating composition, specifically, viscosity increase during storage can be suppressed, and the curing reaction is sufficiently advanced even by heating for a short time (for example, 1 to 10 seconds, specifically 1 to 6 seconds), so that a coating film can be formed. For example, in an IH type furnace, the temperature can be raised in a short time, and specifically, the PMT can be raised to 220°C in about 6 seconds. In the coating composition of the present disclosure, even when such an IH type furnace is used, the curing reaction sufficiently proceeds and a coating film having good physical properties can be formed. Furthermore, by heating the coating composition of the present disclosure at, for example, 170°C to 280°C, the curing reaction sufficiently proceeds, so that a coating film can be formed. In particular, in the coating composition of the present disclosure, a curing reaction sufficiently proceeds even when heated at a relatively low temperature (for example, 170°C to 220°C, specifically, 180°C to 220°C), and a coating film having good physical properties, such as coating film appearance, solvent resistance, folding processability, processing adhesive property, alkali resistance, and acid resistance is obtained. Coating films obtained by heating at a relatively low temperature exhibits the same physical properties as coating films obtained at a commonly used temperature such as 270°C or 280°C. When the coating composition of the present disclosure is used, a coating film having good physical properties, such as solvent resistance, folding processability, processing adhesive property, and chemical resistance is obtained even when the coating film is formed by heating for a short time. The physical properties of the coating film formed by such short-time heating are equivalent to the physical properties of the coating film formed in a normal heating time (for example, 25 seconds, 30 seconds, and 2021347006   28 Aug 2026 the like).

[0067] <Other resins> The coating composition may contain other resin to be used in the field of coating compositions as long as the effects exhibited by the present disclosure are not impaired. Examples of such other resin include polyester resin other than those described above, and modified products thereof (urethane-modified polyester resins, epoxy-modified polyester resins, silicone-modified polyester resins, and the like); urethane resin and modified products thereof (ester-based urethane resins, ether-based urethane resins, carbonate-based urethane resins, epoxy-based urethane resins, and the like); phenol resin and modified products thereof (acrylic-modified phenolic resins, epoxy-modified phenolic resins, and the like); phenoxy resin; alkyd resin and modified products thereof (urethane-modified alkyd resins, acrylic-modified alkyd resins, and the like); and such resins as fluororesin. These resins may be used singly, or two or more of them may be used in combination.

[0068] <Alkanolamine (E)> The coating composition of the present disclosure further comprises an alkanolamine (E). The alkanolamine (E) is a compound having one or more alkanol groups, and particularly is an amine having one or more alkanol groups. In the present disclosure, an alkanol group refers to a group represented by -R2-OH wherein R2 is an alkylene group having 1 or more carbon atoms. The inclusion of the alkanolamine (E) has the advantage of making the storage stability of the coating composition better.

[0069] 2021347006   28 Aug 2026 The alkanolamine (E) preferably has one or more amino groups and two or more alkanol groups per molecule, more preferably has one or more amino groups and two or three alkanol groups per molecule, and still more preferably has one amino group and two or three alkanol groups per molecule.

[0070] In one embodiment, the molecular weight of the alkanolamine (E) is in a range of 60 to 200. The alkanol group of the alkanolamine (E) preferably has 1 to 3, and more preferably 2 to 3 carbon atoms. In one embodiment, the alkanolamine (E) is represented by NR223-n(-R2-OH)n. n is an integer of 1 to 3, preferably 2 or 3, and each R22 independently represents, for example, a hydrogen atom or an alkyl group having 1 to 5 carbon atoms (specifically, 1 to 3 carbon atoms), and each R2 independently represents an alkylene group having 1 to 3 carbon atoms (preferably 2 to 3 carbon atoms). The alkanolamine (E) is not particularly limited, and examples thereof include amines having one alkanol group such as ethanolamine and dimethylaminoethanol; amines having two alkanol groups such as diisopropanolamine and diethanolamine; and amines having three alkanol groups such as triisopropanolamine and triethanolamine. Among these, diisopropanolamine, triisopropanolamine, diethanolamine, and triethanolamine are preferable, and diisopropanolamine and triisopropanolamine are more preferable. As the alkanolamine (E), only one species may be used, or two or more species may be used in combination.

[0071] The content of the alkanolamine (E) is preferably 1.0 to 10.0 parts by mass, more preferably 1.0 to 4.0 parts by mass, still more preferably 1.0 to 3.5 parts by mass, 2021347006   28 Aug 2026 and may be 1.0 to 3.0 parts by mass, based on 100 parts by mass of the total of the resin solid content of the hydroxyl group-containing resin (A) and the resin solid content of the amino resin (B). The inclusion of the alkanolamine (E) in the above range has the advantage of making the storage stability of the coating composition better.

[0072] <Other additives> The coating composition of the present disclosure may comprise additives other than those mentioned above, as necessary. Examples of such other additives include extender pigments; colorants such as coloring pigments and dyes; luster pigments; aggregates (resin particles, silica particles, and the like); waxes; solvents; ultraviolet absorbers (benzophenone-based ultraviolet absorbers); antioxidants (phenolic, sulfide-based, or hindered amine antioxidants, and the like); plasticizers; coupling agents (silane-based, titanium-based, zirconium-based coupling agents, and the like); sagging inhibitors; viscosity control agents; pigment dispersants; pigment wetting agents; surface conditioning agents (silicone-based, organic polymer-based, and the like); leveling agents; color separation inhibitors; suspending agents; antifoaming agents; antifreezing agents; emulsifiers; antiseptic agents; antifungal agents; antibacterial agents; and stabilizers. These additives may be used singly, or two or more of them may be used in combination.

[0073] Examples of the extender pigment include calcium carbonate, barium sulfate, clay, talc, mica, and glass fiber. These may be used singly, or two or more of them may be used in combination. In one embodiment, an amount of the extender pigment is 1 part by mass or more and 40 parts by mass or less, for example 10 parts by mass or more and 30 parts 2021347006   28 Aug 2026 by mass or less, based on 100 parts by mass of the total of the resin solid content of the hydroxyl group-containing resin (A) and the resin solid content of the amino resin (B). When the amount of the extender pigment is in such a range, there is an advantageous effect of improving scratch resistance of a coating film.

[0074] Examples of the coloring pigments include coloring inorganic pigments such as titanium dioxide, carbon black, graphite, iron oxide, and coal dust; coloring organic pigments such as phthalocyanine blue, phthalocyanine green, quinacridone, perylene, anthrapyrimidine, carbazole violet, anthrapyridine, azo orange, flavanthrone yellow, isoindoline yellow, azo yellow, indanthrone blue, dibromanzathrone red, perylene red, azo red, and anthraquinone red; aluminum powder, alumina powder, bronze powder, copper powder, tin powder, zinc powder, iron phosphide, and atomized titanium. These may be used singly, or two or more of them may be used in combination.

[0075] In one embodiment, the coating composition may comprise a heat shielding pigment. The heat shielding pigment to be used is not particularly limited, and examples thereof include the following heat shielding pigments. In the present disclosure, the heat shielding pigment refers to a pigment that does not absorb light in the near-infrared wavelength range (wavelength: 780 nm to 2,500 nm) or has a small light absorption rate in the near-infrared wavelength range (wavelength: 780 nm to 2,500 nm).

[0076] The heat shielding pigment includes inorganic heat shielding pigments and organic heat shielding pigments. Examples of the inorganic heat shielding pigments include metal oxide 2021347006   28 Aug 2026 pigments such as titanium oxide, magnesium oxide, barium oxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, indium oxide, sodium titanate, silicon oxide, nickel oxide, manganese oxide, chromium oxide, iron oxide, copper oxide, cerium oxide, and aluminum oxide; complex inorganic colored pigments such as iron oxidemanganese oxide, iron oxide-chromium oxide (for example, DAIPYROXIDE COLOR BLACK #9595 manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. and Black 6350 manufactured by Asahi Kasei Kogyo Co., Ltd.), iron oxide-cobalt oxidechromium oxide (for example, DAIPYROXIDE COLOR BROWN #9290 and DAIPYROXIDE COLOR BLACK #9590 manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), copper oxide-magnesium oxide (for example, DAIPYROXIDE COLOR BLACK #9598 manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), manganese oxide-bismuth oxide (for example, Black 6301 manufactured by Asahi Kasei Kogyo Co., Ltd.), and manganese oxide-yttrium oxide (for example, Black 6303 manufactured by Asahi Kasei Kogyo Co., Ltd.); metallic pigments such as silicon, aluminum, iron, magnesium, manganese, nickel, titanium, chromium, and calcium; and alloy pigments such as iron-chromium, bismuthmanganese, iron-manganese, and manganese-yttrium. These may be used singly, or two or more of them may be used in combination. Examples of the organic heat shielding pigment include azo pigments, azomethine pigments, lake pigments, thioindigo pigments, anthraquinone pigments (anthanthrone pigment, diaminoanthraquinonyl pigment, indanthrone pigment, flavanthrone pigment, anthrapyrimidine pigment, and the like), perylene pigments, perinone pigments, diketopyrrolopyrrole pigments, dioxazine pigments, phthalocyanine pigments, quinophthalone pigments, quinacridone pigments, isoindoline pigments, and isoindolinone pigments. These can be used singly or two or more of them may be used 2021347006   28 Aug 2026 in combination.

[0077] Examples of the luster pigments include foil pigments such as aluminum foil, bronze foil, tin foil, gold foil, silver foil, titanium metal foil, stainless steel foil, alloy foil of nickel and copper, and the like, and foil-like phthalocyanine blue. These may be used singly, or two or more of them may be used in combination.

[0078] As the wax, waxes known to those skilled in the art for coating materials can be used, and examples thereof include microcrystalline wax, polyethylene wax, polypropylene wax, paraffin wax, carnauba wax, and modified products thereof. These may be used singly, or two or more of them may be used in combination.

[0079] Examples of the solvent include water; glycol-based organic solvents such as ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monobutyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and propylene glycol monomethyl ether acetate; alcohol-based organic solvents such as methanol, ethanol, and isopropyl alcohol; ether-based organic solvents such as dioxane and tetrahydrofuran; ester-based organic solvents such as 3-methoxybutyl acetate, ethyl acetate, isopropyl acetate, and butyl acetate; ketone-based organic solvents such as methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclohexanone, and isophorone; nitrogen-containing organic solvents such as N-methyl-2-pyrrolidone; toluene, pentane, isopentane, hexane, isohexane, and cyclohexane, solvent naphtha, mineral spirits, T-SOL 100 and T-SOL 150 (both are aromatic hydrocarbon-based solvents, manufactured 2021347006   28 Aug 2026 by JXTG Energy Corporation). These may be used singly, or two or more of them may be used in combination.

[0080] The coating composition of the present invention may be either a water-borne coating material or an organic solvent-borne coating material.

[0081] [Method for preparing coating composition] The method for preparing the coating composition according to the present disclosure is not particularly limited. For example, the coating composition can be prepared by mixing ingredients using a mixing machine such as a roller mill, a ball mill, a beads mill, a pebble mill, a sand grind mill, a pot mill, a paint shaker, or a disper, a dispersing machine, a kneading machine, or the like.

[0082] [Method for manufacturing coating film] The method for producing a coating film of the present disclosure comprises: a step of applying the coating composition of the present disclosure to an article to be coated such as a steel sheet to form an applied film; and a step of heating the article to dry and / or cure the applied film.

[0083] Examples of the article to be coated include a galvanized steel sheet, a zincaluminum alloy plated steel sheet, an aluminum alloy plated steel sheet, and a hot-dip zinc-aluminum-magnesium alloy plated steel sheet manufactured by a melting method or an electrolytic method, a stainless steel sheet, and a cold rolled steel sheet. In addition to these steel sheets or plated steel sheets, metal sheets such as aluminum sheet (including aluminum alloy sheet) can also be used as an article to be coated. 2021347006   28 Aug 2026

[0084] The article to be coated is preferably surface-treated. Specifically, the article to be coated is preferably subjected to chemical conversion treatment after being subjected to pretreatment such as alkali degreasing treatment, hot water washing treatment, or water washing treatment. The chemical conversion treatment may be carried out by a conventionally known method, and examples thereof include chromate treatment and non-chromate treatment such as zinc phosphate treatment. While the surface treatment may be appropriately selected depending on the steel sheet to be used, a treatment free of heavy metals is preferable. By applying the coating composition of the present disclosure to an article subjected to chemical conversion treatment as described above, the adhesive property of the coating film to a metal sheet surface is improved and corrosion resistance is also improved. It is also possible to form an undercoat coating film (primer coating film) on the metal sheet surface subjected to the chemical conversion treatment and apply the coating composition onto the undercoat coating film.

[0085] The method of applying the coating composition is not particularly limited, and conventionally publicly known means such as a roll coater, an airless spray, an electrostatic spray, and a curtain flow coater can be employed, and the coating composition is preferably applied with a roll coater or a curtain flow coater.

[0086] The temperature at which the applied film formed by applying the coating composition is dried and / or cured, that is, the peak temperature (the maximum temperature to which an article to be coated such as a steel sheet reaches) is, for example, 170°C to 280°C, specifically, 180°C to 270°C, and may be 200°C to 250°C. 2021347006   28 Aug 2026 The drying and / or curing time may be, for example, as short as 1 to 10 seconds, specifically 1 to 6 seconds. The method for drying and / or curing the applied film is not particularly limited, and heating means such as hot air heating, infrared heating, or induction heating can be used.

[0087] That is, the method for producing a coating film of the present disclosure may comprise: a step of applying the coating composition of the present disclosure to an article to be coated to form an applied film; and a step of drying and / or curing the applied film under a condition in which a peak temperature of the article is 180°C to 270°C and a drying and / or curing time is 1 to 10 seconds.

[0088] The film thickness (dry film thickness) of a coating film obtained by baking the applied film and curing the resin is usually 1 to 30 pm, and for example, in the case of a top coating film, it is preferably 5 to 30 pm. For example, the dry film thickness may be 5 to 25 pm.

[0089] In the present disclosure, drying and / or curing means performing at least one of drying and curing, and preferably performing both drying and curing.

[0090] [Precoated metal sheet] The precoated metal sheet of the present disclosure comprises a coating film formed from the coating composition according to the present disclosure on at least one 2021347006   28 Aug 2026 surface of the metal sheet. For example, the film thickness of a coating film formed from the coating composition according to the present disclosure is 5 gm or more and 30 gm or less, and in one embodiment, the film thickness is 10 gm or more and 25 gm or less. As the metal sheet, those described above as an article to be coated can be used.

[0091] When the precoated metal sheet comprises a coating film formed from the coating composition according to the present disclosure on one surface of a metal sheet, the other surface may be a coating film formed from a known coating composition. For example, the other surface may have a coating film formed from a publicly known coating composition such as a coating composition containing an epoxy resin.

[0092] The precoated metal sheet may have an undercoat coating film between the metal sheet and the coating film formed from the coating composition of the present disclosure. The undercoat coating material may be conventionally publicly known one, and examples thereof include a conventionally publicly known non-chromium rustproof coating material. By having an undercoat coating film, the adhesive property and the corrosion resistance of a coating film formed from the coating composition of the present disclosure can be enhanced. In one embodiment, the film thickness of the undercoat coating film is 3 gm or more and 15 gm or less, for example, 5 gm or more and 10 gm or less.

[0093] In one embodiment, the precoated metal sheet of the present disclosure can be 2021347006   28 Aug 2026 produced by a method comprising: a step of applying the coating composition according to the present disclosure to at least one surface of a metal sheet such that a film thickness after curing is 5 to 25 pm to form an applied film; and a step of drying and / or curing the applied film under a condition in which a peak temperature of the metal sheet is 180°C to 270°C and a drying and / or curing time is 1 to 10 seconds. In the method for producing a precoated metal sheet, formation of an applied film and drying and / or curing of the applied film may be performed in the same manner as in the method for producing a coating film described above. EXAMPLES

[0094] The present invention will be described more specifically with reference to the following non-limiting examples, but the present invention is not limited to the examples. In the examples, “parts” and “%” are on a mass basis unless otherwise indicated.

[0095] Details of the hydroxyl group-containing resins (A1) to (A13) used in Examples, Comparative Examples, and Reference Examples are as shown in Tables 1A to 1C.

[0096] [Table 1A] Hydroxyl group-containing resin (A) (A1) (A2) (A3) (A4) Polyester resin 1 Polyester resin 2 Polyester resin 3 Polyester resin 4 2021347006   28 Aug 2026 Commercial raw material ETERKYD 5055R-65-3 DYNAPL LH 538 ETERKYD 50528-R-70 SYNOLAC 9605 Manufacturer Eternal Materials Co., Ltd. Evonik Industries AG Eternal Materials Co., Ltd. ARKEMA Solid concentration (mass%) 65 65 70 65 Number-average molecular weight 4,000 3,000 2,500 2,000 Hydroxyl value (mg KOH / g) 60 45 65 50

[0097] [Table 1B] Hydroxyl group-containing resin (A) (A5) (A6) (A7) (A8) Polyester resin 5 Polyester resin 6 Polyester resin 7 Polyester resin 8 Commercial raw material DYNAPL LH 724 DYNAPL LH 727 ETERKYD 3103-X-70 DYNAPOL LH820 Manufacturer Evonik Industries AG Evonik Industries AG Eternal Materials Co., Ltd. Evonik Industries AG Solid concentration (mass%) 70 65 70 50 Number-average molecular weight 2,000 2,000 1,500 5,000 Hydroxyl value (mg KOH / g) 70 100 125 20

[0098] [Table 1C] Hydroxyl group-containing resin (A) (A9) (A10) (A11) (A12) (A13) Polyester resin 9 Polyester resin 10 Polyester resin 11 Epoxy resin 1 Acrylic resin 1 Commercial raw material DYNAPOL LH826 ETERKYD 5084-R-60-6E BECKOLITE M-6902-50 jER1007 ACRYDIC A830 Manufacturer Evonik Industries AG Eternal Materials Co., Ltd. DIC Corporation Mitsubishi Chemical Corporation DIC Corporation Solid concentration (mass%) 55 60 50 100 60 Number-average molecular weight 6,000 7,200 11,700 2,900 3,000 Hydroxyl value (mg KOH / g) 20 64 8 170 80

[0099] The hydroxyl group-containing resin (A 12) (epoxy resin 1) used was prepared by dissolving 90 parts by mass of jER1007 (manufactured by Mitsubishi Chemical Corporation; solid concentration: 100 mass%) in 210 parts by mass of cyclohexanone to 2021347006   28 Aug 2026 adjust the solid concentration to 30 mass%.

[0100] <Amino resin (B)> Details of the amino resins (B1) to (B6) are as shown in Tables 2A and 2B. The details of the isocyanate compound used in Comparative Examples are also shown in Table 2B.

[0101] [Table 2A] Amino resin (B) Amino resin (B1) Amino resin (B2) Amino resin (B3) Amino resin (B4) Melamine resin 1 Melamine resin 2 Melamine resin 3 Melamine resin 4 Commercial raw material CYMEL 303 CYMEL 350 CYMEL 235 CYMEL 325 Manufacturer Allnex Japan Inc. Allnex Japan Inc. Allnex Japan Inc. Allnex Japan Inc. Solid concentration (%) 100 100 100 80 Functional group Fully Alkylated Fully Alkylated Fully Alkylated Imino Alkyl group type Methyl Methyl Methyl / butyl mix Methyl

[0102] [Table 2B] Amino resin (B) Amino resin (B5) Amino resin (B6) Isocyanate compound Melamine resin 5 Melamine resin 6 Polyisocyanate compound 1 Commercial raw material MYCOAT 212 CYMEL 370 DESMODUR BL3175 Manufacturer Allnex Japan Inc. Allnex Japan Inc. Sumika Covestro Urethane Co., Ltd. Solid concentration (%) 90 88 75 Functional group Imino Methylol Blocked isocyanate Alkyl group type Methyl / butyl mix Methyl -

[0103] <Production example of covalently bonded blocked acid catalyst (C11)> A reaction vessel equipped with a thermometer, a condenser, a dropping funnel, and a stirrer was charged with 37 parts by mass of Nacure 1051 (manufactured by King Industries, Ltd.), and the temperature was raised to 90°C under a nitrogen atmosphere. 2021347006   28 Aug 2026 To this, a mixed solution prepared by dissolving 220 parts by mass of jER 1010 (bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation) as an epoxy resin in 220 parts by mass of methyl propylene glycol (manufactured by Nippon Nyukazai Co., Ltd.) in advance was dropped at a constant rate over 60 minutes through the dropping funnel. Thereafter, the reactant temperature was held at 90°C for 60 minutes, and thus covalently bonded blocked acid catalyst (C11) was prepared. After the synthesis, it was confirmed that the solid acid value of the covalently bonded blocked acid catalyst (C11) was 0, and thereby it was confirmed that the blocking agent was covalently bonded to all sulfonic acid groups.

[0104] <Production examples of covalently bonded blocked acid catalysts (C12) to (C28)> Covalently bonded blocked acid catalysts (C12) to (C28) were prepared in the same manner as in Production Example of (C11) except that the type and amount of each component were changed as described in the table. In addition, as in the case of (C11), it was confirmed that the solid acid value of each covalently bonded blocked acid catalyst was 0 after synthesis.

[0105] Various characteristic values of each component and the prepared covalently bonded blocked acid catalysts (C11) to (C28) are shown in Tables 3A to 3D.

[0106] <Acid catalysts (c31), (c32)> <Production example of acid catalyst (c31)> A reaction vessel equipped with a thermometer, a condenser, a dropping funnel, and a stirrer was charged with 185 parts by mass of Nacure 1051 (manufactured by 2021347006   28 Aug 2026 King Industries, Ltd.), and the temperature was raised to 40°C under a nitrogen atmosphere. To this, a mixed solution prepared by dissolving 20 parts by mass of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) in 20 parts by mass of methyl propylene glycol (manufactured by Nippon Nyukazai Co., Ltd.) in advance was dropped at a constant rateover 60 minutes through the dropping funnel. Thereafter, the reactant temperature was held at 40°C for 60 minutes, and thus acid catalyst (C31) was prepared. After the synthesis, it was confirmed that the solid acid value of the acid catalyst (C31) was 0, and thereby it was confirmed that the blocking agent was covalently bonded to all sulfonic acid groups.

[0107] Characteristic values of the prepared acid catalysts (c31) and (c32) are shown in Table 3B. 2021347006   28 Aug 2026

[0108] [Table 3A] Covalently bonded blocked acid catalyst (C) (C11) (C12) (C13) (C14) (C15) Raw material Sulfonic acid Nacure 1051 37 37 37 37 37 TAYCACURE AC400S TAYCACURE AC700 Subtotal 37 37 37 37 37 Epoxy resin jER 1004 66 jER 1007 116 jER 1009 152 jER 1010 220 jER1255HX30 400 jER 1009F Amine compound Triethylamine Solvent Methyl propylene glycol 220 152 116 66 933 Grand total 477 341 269 169 1,370 Solid concentration (mass%) 50 50 50 50 31 Blocking agent Epoxy resin Epoxy resin Epoxy resin Epoxy resin Epoxy resin Number-average molecular weight of acid catalyst 6,000 4,300 3,400 2,100 10,500

[0109] [Table 3B] Covalently bonded blocked acid catalyst (C) Acid catalyst 1 Acid catalyst 2 (C16) (C17) (C18) (c31) (c32) Raw material Sulfonic acid Nacure 1051 37 185 200 TAYCACURE AC400S 33 TAYCACURE AC700 28 Subtotal 37 33 28 185 200 Epoxy resin jER 1004 jER 1007 jER 1009 jER 1010 220 220 jER1255HX30 jER 1009F 116 Amine compound Triethylamine 20 Solvent Methyl propylene glycol 116 220 220 20 Grand total 269 473 468 225 200 Solid concentration (mass%) 50 47 47 50 50 Blocking agent Epoxy resin Epoxy resin Epoxy resin Triethylamine None Number-average molecular weight of acid catalyst 3,400 5,800 5,700 - - 2021347006   28 Aug 2026

[0110] [Table 3C] Covalently bonded blocked acid catalyst (C) (C21) (C22) (C23) (C24) (C25) Raw material Sulfonic acid Nacure 1051 37 37 37 37 37 TAYCACURE AC400S TAYCACURE AC700 Subtotal 37 37 37 37 37 Glycidyl ether compound Phenyl glycidyl ether 6 o-Cresyl glycidyl ether 7 DY-BP 5 EPOGOSEY 2EH 7 EPOGOSEY LA (D) 10 EPOGOSEY AN Amine compound Triethylamine Solvent Methyl propylene glycol 6 7 5 7 10 Grand total 49 51 47 51 57 Solid concentration (mass%) 50 50 50 50 50 Blocking agent Glycidyl ether compound Glycidyl ether compound Glycidyl ether compound Glycidyl ether compound Glycidyl ether compound Molecular weight of acid catalyst 610 590 624 646 702

[0111] 2021347006   28 Aug 2026 [Table 3D] Covalently bonded blocked acid catalyst (C) (C26) (C27) (C28) Raw material Sulfonic acid Nacure 1051 37 TAYCACURE AC400S 33 TAYCACURE AC700 28 Subtotal 37 33 28 Glycidyl ether compound Phenyl glycidyl ether 6 6 o-Cresyl glycidyl ether DY-BP EPOGOSEY 2EH EPOGOSEY LA (D) EPOGOSEY AN 10 Amine compound Triethylamine Solvent Methyl propylene glycol 10 6 6 Grand total 57 45 40 Solid concentration (mass%) 50 43 33 Blocking agent Glycidyl ether compound Glycidyl ether compound Glycidyl ether compound Molecular weight of acid catalyst 711 476 322

[0112] The compounds shown in Tables 3A to 3D are as follows. [Sulfonic acid] - Nacure 1051: Dinonylnaphthalenesulfonic acid (manufactured by King Industries, Ltd.) Active ingredient concentration: 50 mass% - TAYCACURE AC400S: Dodecylbenzenesulfonic acid (manufactured by Tayca Corporation) Active ingredient concentration:40 mass% - TAYCACURE AC700: Paratoluenesulfonic acid (manufactured by Tayca Corporation) Active ingredient concentration: 25 mass% [Epoxy resin] - jER 1004: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation) Number-average molecular weight: 1,700, solid concentration: 100 mass% 2021347006   28 Aug 2026 - jER 1007: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation) Number-average molecular weight: 2,900, solid concentration: 100 mass% - jER 1009: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation) Number-average molecular weight: 3,800, solid concentration: 100 mass% - jER 1010: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation) Number-average molecular weight: 5,500, solid concentration: 100 mass% - jER 1255HX30: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation) Number-average molecular weight: 10,000, solid concentration: 100 mass% - jER 1009F: Bisphenol F type epoxy resin (manufactured by Mitsubishi Chemical Corporation) Number-average molecular weight: 2,900, solid concentration: 100 mass% [Glycidyl ether compound] - Phenyl glycidyl ether: Aromatic glycidyl ether compound (manufactured by Yokkaichi Chemical Co., Ltd.) Molecular weight: 150, active ingredient concentration: 100 mass% - o-Cresyl glycidyl ether: Aromatic glycidyl ether compound (manufactured by Yokkaichi Chemical Co., Ltd.) Molecular weight: 164, active ingredient concentration: 100 mass% - DY-BP: Aliphatic glycidyl ether compound (butyl glycidyl ether manufactured by Yokkaichi Chemical Co., Ltd.) Molecular weight: 130, active ingredient concentration: 100 mass% 2021347006   28 Aug 2026 - EPOGOSEY 2EH: Aliphatic glycidyl ether compound (2-ethylhexyl glycidyl ether manufactured by Yokkaichi Chemical Co., Ltd.) Molecular weight: 186, active ingredient concentration: 100 mass% - EPOGOSEY LA (D): Aliphatic glycidyl ether compound (lauryl glycidyl ether manufactured by Yokkaichi Chemical Co., Ltd.) Molecular weight: 242, active ingredient concentration: 100 mass% - EPOGOSEY AN: Aliphatic glycidyl ether compound (C12-13 mixed alcohol glycidyl ether manufactured by Yokkaichi Chemical Co., Ltd.) Molecular weight: 251, active ingredient concentration: 100 mass% [Others] - Amine compound: Triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) Active ingredient concentration: 100 mass% - Solvent: Methyl propylene glycol: propylene glycol monomethyl ether (manufactured by Nippon Nyukazai Co., Ltd.)

[0113] <Production example of phosphoric acid-modified epoxy resin (D1)> A reaction vessel equipped with a thermometer, a condenser, a dropping funnel, and a stirrer was charged with 43 parts by mass of an 85% aqueous phosphoric acid solution and 22 parts by mass of propylene glycol monomethyl ether, and the temperature was raised to 80°C under a nitrogen atmosphere. To this, a mixed solution prepared by dissolving 179 parts by mass of jER 834 (bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation) as an epoxy resin in 32 parts by mass of propylene glycol monomethyl ether in advance was dropped at a constant rate over 60 minutes through the dropping funnel. Thereafter, the reactant temperature was held at 80°C for 60 minutes, and thus phosphoric acid-modified epoxy resin (D1) was 2021347006   28 Aug 2026 prepared.

[0114] <Production examples of phosphoric acid-modified epoxy resins (D2) to (D7)> Phosphoric acid-modified epoxy resins (D2) to (D7) were prepared in the same manner as in Production Example of (D1) except that the type and amount of each component were changed as described in the table. Characteristic values of the components and the prepared phosphoric acid-modified epoxy resins (D1) to (D7) are shown in Tables 4A and 4B.

[0115] [Table 4A] Phosphoric acid-modified epoxy resin (D) (D1) (D2) (D3) (D4) Raw material 85% Phosphoric acid 43 43 43 43 Methyl propylene glycol 22 22 22 22 Subtotal 65 65 65 65 jjER 825 130 jER 828 141 jER 834 179 jER 1009 1,451 jER 1010 jER 1009F Methyl propylene glycol 32 25 23 1,451 Grand total 276 231 218 2,967 Solid concentration (%) 78 77 76 50 Number-average molecular weight 570 470 440 3,900 Number of phosphoric acid groups in one molecule 1 1 1 1

[0116] 2021347006   28 Aug 2026 [Table 4B] Phosphoric acid-modified epoxy resin (D) (D5) (D6) (D7) Raw material 85% Phosphoric acid 43 43 86 Methyl propylene glycol 22 22 44 Subtotal 65 65 130 jER 825 jER 828 jER 834 179 jER 1009 jER 1010 2,100 jER 1009F 1,107 Methyl propylene glycol 2,100 1,107 32 Grand total 4,265 2,279 341 Solid concentration (%) 50 50 74 Number-average molecular weight 5,600 3,000 660 Number of phosphoric acid groups in one molecule 1 1 2

[0117] The compounds shown in Table 4A and Table 4B are as follows. [Phosphoric acid] - 85% phosphoric acid: manufactured by Kishida Chemical Co., Ltd. [Epoxy resin] - jER 825: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation) Number-average molecular weight: 340, solid concentration: 100 mass% - jER 828: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation) Number-average molecular weight: 370, solid concentration: 100 mass% - jER 834: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation) Number-average molecular weight: 470, solid concentration: 100 mass% - jER 1009: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation) Number-average molecular weight: 3,800, solid concentration: 2021347006   28 Aug 2026 100 mass% - jER 1010: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation; Number-average molecular weight) 5,500, solid concentration: 100 mass% - jER 1009F: Bisphenol F type epoxy resin (manufactured by Mitsubishi Chemical Corporation) Number-average molecular weight: 2,900, solid concentration: 100 mass% [Others] - Solvent: Methyl propylene glycol: propylene glycol monomethyl ether (manufactured by Nippon Nyukazai Co., Ltd.)

[0118] <Alkanolamine (E)> Details of the alkanolamine (E) are as shown in Table 5A and Table 5B.

[0119] 2021347006   28 Aug 2026 [Table 5A] Alkanolamine (E) (E1) (E2) (E3) Commercial raw material Diisopropanolamine Triisopropanolamine Monoisopropanolamine Manufacturer Tokyo Chemical Industry Co., Ltd. Tokyo Chemical Industry Co., Ltd. Tokyo Chemical Industry Co., Ltd. Active ingredient concentration (mass%) 100 100 100 Number of alkanol groups 2 3 1 Alkanol type Isopropanol Isopropanol Isopropanol

[0120] [Table 5B] Alkanolamine (E) (E4) (E5) (E6) Commercial raw material Diethanolamine Triethanolamine Dimethylaminoethanol Manufacturer Tokyo Chemical Industry Co., Ltd. Tokyo Chemical Industry Co., Ltd. Tokyo Chemical Industry Co., Ltd. Active ingredient concentration (mass%) 100 100 100 Number of alkanol groups 2 3 1 Alkanol type Ethanol Ethanol Ethanol

[0121] <Production example of coating composition 1> 107.7 parts by mass of the hydroxyl group-containing resin (A1), 2.4 parts by mass of T-SOL 100 (manufactured by JXTG Energy Corporation) and 2.4 parts by mass of ethylene glycol monobutyl ether (manufactured by The Dow Chemical Company) as solvents, and 67.0 parts by mass of TIPAQUE CR-97 (titanium oxide, manufactured by Ishihara Sangyo Kaisha, Ltd.) as a pigment were mixed by stirring with a disper, affording a mixture. Next, the whole amount of the mixture obtained and glass beads (in the same amount as the total parts by mass of the mixture) were put in a tabletop SG Mill 1500 W type disperser (manufactured by Ohira System Co., Ltd.), and pigment dispersion was performed until the particle size of TIPAQUE CR-97 became 10 gm or less, thereby preparing a pigment dispersion coating material. Furthermore, 30.0 parts by mass of the amino resin (B1), 38.5 parts by mass of the covalently bonded blocked acid catalyst (C11), and 3.9 parts by mass of the 2021347006   28 Aug 2026 phosphoric acid-modified epoxy resin (D1) were mixed with 179.5 parts by mass of the pigment dispersion coating material by stirring with a disper, affording a coating composition. The resulting coating composition was diluted with a mixed solution of T-SOL 100 / ethylene glycol monobutyl ether = 1 / 1 (mass ratio) in a Ford cup No. 4 such that 100 seconds (at 25°C) was achieved, affording coating composition 1.

[0122] <Production examples of coating compositions 2 to 69> Coating compositions 2 to 69 were prepared in the same manner as in the production example of the coating composition 1 except that the type and amount of each component were changed as shown in Tables 6A to 6P.

[0123] 2021347006   28 Aug 2026 [Table 6A] Example 1 Example 2 Example 3 Example 4 Example 5 Coating composition 1 Coating composition 2 Coating composition 3 Coating composition 4 Coating composition 5 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 138.5 92.3 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 10.0 40.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) 38.5 38.5 38.5 128.2 256.4 (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 3.9 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) (E6) Total 180.1 190.8 174.7 269.8 398.0 2021347006   28 Aug 2026

[0124] [Table 6B] Example 6 Example 7 Example 8 Example 9 Example 10 Coating composition 6 Coating composition 7 Coating composition 8 Coating composition 9 Coating composition 10 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 107.7 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) 38.5 38.5 38.5 38.5 38.5 (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 1.3 12.8 3.9 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) 1.0 0.5 3.0 (E2) (E3) (E4) (E5) (E6) Total 177.4 189.0 181.1 180.6 183.1 2021347006   28 Aug 2026

[0125] [Table 6C] Example 11 Example 12 Example 13 Example 14 Example 15 Coating composition 11 Coating composition 12 Coating composition 13 Coating composition 14 Coating composition 15 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 107.7 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) 38.5 38.5 38.5 38.5 38.5 (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 (D2) 3.9 (D3) 3.9 (D4) 6.0 (D5) (D6) (D7) Alkanolamine (E) (E1) 4.0 6.0 (E2) (E3) (E4) (E5) (E6) Total 184.1 186.1 180.1 180.1 182.2 2021347006   28 Aug 2026

[0126] [Table 6D] Example 16 Example 17 Example 18 Example 19 Example 20 Coating composition 16 Coating composition 17 Coating composition 18 Coating composition 19 Coating composition 20 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 107.7 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) 38.5 38.5 38.5 (C12) 27.8 (C13) 21.7 (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 (D2) (D3) (D4) (D5) 6.0 (D6) 6.0 (D7) 4.1 Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) (E6) Total 182.2 182.2 180.2 169.4 163.3 2021347006   28 Aug 2026

[0127] [Table 6E] Example 21 Example 22 Example 23 Example 24 Example 25 Coating composition 21 Coating composition 22 Coating composition 23 Coating composition 24 Coating composition 25 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 107.7 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) (C12) (C13) (C14) 13.8 (C15) 107.1 (C16) 21.7 (C17) 53.6 (C18) 100.0 (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 3.9 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) (E6) Total 155.4 248.7 163.3 195.2 241.6 2021347006   28 Aug 2026

[0128] [Table 6F] Example 26 Example 27 Example 28 Example 29 Example 30 Coating composition 26 Coating composition 27 Coating composition 28 Coating composition 29 Coating composition 30 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 107.7 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) 4.0 (C22) 4.1 (C23) 3.8 (C24) 4.1 (C25) 4.6 (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 3.9 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) (E6) Total 145.6 145.7 145.4 145.7 146.2 2021347006   28 Aug 2026

[0129] [Table 6G] Example 31 Example 32 Example 33 Example 34 Example 35 Coating composition 31 Coating composition 32 Coating composition 33 Coating composition 34 Coating composition 35 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 107.7 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) 13.2 26.5 (C22) (C23) (C24) (C25) (C26) 4.6 (C27) 5.1 (C28) 8.6 Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 3.9 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) (E6) Total 146.2 146.7 150.2 154.8 168.1 2021347006   28 Aug 2026

[0130] [Table 6H] Example 36 Example 37 Example 38 Example 39 Example 40 Coating composition 36 Coating composition 37 Coating composition 38 Coating composition 39 Coating composition 40 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 (A2) Polyester resin 2 107.7 (A3) Polyester resin 3 100.0 (A4) Polyester resin 4 107.7 (A5) Polyester resin 5 100.0 (A6) Polyester resin 6 107.7 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) 38.5 38.5 38.5 38.5 38.5 (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 3.9 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) (E6) Total 180.1 172.4 180.1 172.4 180.1 2021347006   28 Aug 2026

[0131] [Table 6I] Example 41 Example 42 Example 43 Example 44 Example 45 Coating composition 41 Coating composition 42 Coating composition 43 Coating composition 44 Coating composition 45 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 100.0 (A8) Polyester resin 8 140.0 (A9) Polyester resin 9 127.3 (A10) Polyester resin 10 116.7 (A11) Polyester resin 11 140.0 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) 38.5 38.5 38.5 38.5 38.5 (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 3.9 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) (E6) Total 172.4 212.4 199.6 189.0 212.4 2021347006   28 Aug 2026

[0132] [Table 6J] Example 46 Example 47 Example 48 Example 49 Example 50 Coating composition 46 Coating composition 47 Coating composition 48 Coating composition 49 Coating composition 50 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 233.3 (A13) Acrylic resin 1 116.7 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 (B2) Melamine resin 2 30.0 (B3) Melamine resin 3 30.0 (B4) Melamine resin 4 37.5 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) 38.5 38.5 38.5 38.5 38.5 (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 3.9 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) (E6) Total 305.7 189.1 180.1 180.1 187.6 2021347006   28 Aug 2026

[0133] [Table 6K] Example 51 Example 52 Example 53 Example 54 Example 55 Coating composition 51 Coating composition 52 Coating composition 53 Coating composition 54 Coating composition 55 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 107.7 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 33.3 (B6) Melamine resin 6 34.1 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) 38.5 38.5 38.5 38.5 38.5 (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 3.9 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) 3.0 (E3) 3.0 (E4) 3.0 (E5) (E6) Total 183.4 184.1 183.1 183.1 183.1 2021347006   28 Aug 2026

[0134] [Table 6L] Example 56 Example 57 Example 58 Example 59 Example 60 Coating composition 56 Coating composition 57 Coating composition 1 Coating composition 1 Coating composition 1 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 107.7 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) 38.5 38.5 38.5 38.5 38.5 (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 3.9 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) 3.0 (E6) 3.0 Total 183.1 183.1 180.1 180.1 180.1 2021347006   28 Aug 2026

[0135] [Table 6M] Example 61 Example 62 Example 63 Example 64 Coating composition 1 Coating composition 1 Coating composition 1 Coating composition 1 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) 38.5 38.5 38.5 38.5 (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) (E6) Total 180.1 180.1 180.1 180.1 2021347006   28 Aug 2026

[0136] [Table 6N] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Coating composition 58 Coating composition 59 Coating composition 60 Coating composition 61 Coating composition 62 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 146.2 76.9 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 5.0 50.0 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) 38.5 38.5 12.8 0.0 384.6 (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 3.9 3.9 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) (E6) Total 193.5 169.3 154.4 141.6 526.2 2021347006   28 Aug 2026

[0137] [Table 6O] Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Coating composition 63 Coating composition 64 Coating composition 65 Coating composition 66 Coating composition 67 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 107.7 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 30.0 30.0 30.0 30.0 30.0 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 Covalently bonded blocked acid catalyst (C) (C11) 38.5 38.5 38.5 (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine 3.7 Acid catalyst 2 (c32) No blocking agent 3.0 Phosphoric acid-modified epoxy resin (D) (D1) 0.6 0.0 19.2 3.9 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) (E6) Total 176.8 176.2 195.4 145.3 144.6 2021347006   28 Aug 2026

[0138] [Table 6P] Comparative Example 11 Comparative Example 12 Reference Example 1 Coating composition 68 Coating composition 69 Coating composition 69 Hydroxyl group-containing resin (A) (A1) Polyester resin 1 107.7 107.7 107.7 (A2) Polyester resin 2 (A3) Polyester resin 3 (A4) Polyester resin 4 (A5) Polyester resin 5 (A6) Polyester resin 6 (A7) Polyester resin 7 (A8) Polyester resin 8 (A9) Polyester resin 9 (A10) Polyester resin 10 (A11) Polyester resin 11 (A12) Epoxy resin 1 (A13) Acrylic resin 1 Amino resin (B) (B1) Melamine resin 1 (B2) Melamine resin 2 (B3) Melamine resin 3 (B4) Melamine resin 4 (B5) Melamine resin 5 33.3 33.3 (B6) Melamine resin 6 Isocyanate compound Polyisocyanate compound 1 40.0 Covalently bonded blocked acid catalyst (C) (C11) 38.5 (C12) (C13) (C14) (C15) (C16) (C17) (C18) (C21) (C22) (C23) (C24) (C25) (C26) (C27) (C28) Acid catalyst 1 (c31) Blocking agent: triethylamine Acid catalyst 2 (c32) No blocking agent Phosphoric acid-modified epoxy resin (D) (D1) 3.9 (D2) (D3) (D4) (D5) (D6) (D7) Alkanolamine (E) (E1) (E2) (E3) (E4) (E5) (E6) Total 190.6 141.0 141.0

[0139] (Examples 1 to 64, Comparative Examples 1 to 12, and Reference Example 1) 2021347006   28 Aug 2026 As to Examples 1 to 64, Comparative Examples 1 to 12, and Reference Example 1, evaluations were carried out using the coating compositions shown in Tables 6A to 6P, respectively. The evaluation results are shown in Tables 7A to 7P. In Comparative Example 11, a coating composition in which 0.5 parts by mass of TVS#Tin Lau (dibutyltin dilaurate, manufactured by Nitto Kasei Co., Ltd.; active ingredient concentration: 100 mass%) was further added as a catalyst was used. The value of “parts by mass (solid content) of (B) based on 100 parts by mass of the solid content of (A) and (B)” in Comparative Example 11 in Table 7N means "parts by mass (solid content) of the polyisocyanate compound 1 based on 100 parts by mass of the solid content of (A) and the polyisocyanate compound 1".

[0140] In addition, the coated steel sheet in Example 1 was manufactured as shown in the following production example.

[0141] <Production example of coated steel sheet of Example 1> A 0.4 mm thick molten zinc plated steel sheet was alkali-degreased, and then subjected to non-chromium chemical conversion treatment by applying a phosphoric acid treatment agent, SURFCOAT EC2310 (manufactured by Nippon Paint Surf Chemicals Co., Ltd.) on the front and back surfaces of the steel sheet, followed by drying. Next, the coating composition 1 was applied on a surface of the steel sheet using a bar coater such that the dry coating film was 10 gm in thickness, and baked (heated) for 6 seconds using an induction heater type furnace under the condition that the peak temperature (PMT) of the steel sheet was 220°C to form a surface coating film, thereby affording a coated steel sheet. 2021347006   28 Aug 2026

[0142] <Production examples of coated steel sheets in Examples 2 to 64, Comparative Examples 1 to 12 and Reference Example 1> The coated steel sheets in Examples 2 to 64, Comparative Examples 1 to 12, and Reference Example 1 were produced by changing the coating film composition, the baking temperature, and the baking time to the conditions shown in Tables 7A to 7P in the production example of the coated steel sheet in Example 1. In Tables 7A to 7P, “based on 100 parts by mass of the solid content of (A) and (B) ” means "based on 100 parts by mass of the total of the resin solid content of the hydroxyl group-containing resin (A) and the resin solid content of the amino resin (B)".

[0143] [Table 7A] Example 1 Example 2 Example 3 Example 4 Example 5 Coating composition 1 Coating composition 2 Coating composition 3 Coating composition 4 Coating composition 5 Hydroxyl group-containing resin (A) (A1) (A1) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B1) (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C11) (C11) (C11) (C11) (C11) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) (D1) Alkanolamine (E) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 90.0 60.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 10.0 40.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 5.0 10.0 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O O O O O Storage stability Viscosity ratio (%) 140 140 140 140 140 Solvent resistance 5 3 5 5 5 Processability Folding test 5 5 4 5 4 Adhesive property 5 4 4 5 5 Alkali resistance 8FM 8FM 8FM 8FM 8FM Acid resistance 8FM 8FM 8FM 8FM 8FM 2021347006   28 Aug 2026

[0144] [Table 7B] Example 6 Example 7 Example 8 Example 9 Example 10 Coating composition 6 Coating composition 7 Coating composition 8 Coating composition 9 Coating composition 10 Hydroxyl group-containing resin (A) (A1) (A1) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B1) (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C11) (C11) (C11) (C11) (C11) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) (D1) Alkanolamine (E) (E1) (E1) (E1) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 1.5 1.5 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 1.0 10.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 1.0 0.5 3.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O O O O O Storage stability Viscosity ratio (%) 140 140 120 130 110 Solvent resistance 4 5 5 5 5 Processability Folding test 5 4 5 5 5 Adhesive property 4 4 5 5 5 Alkali resistance 8FM 8FM 8FM 8FM 8FM Acid resistance 8FM 8FM 8FM 8FM 8FM

[0145] 2021347006   28 Aug 2026 [Table 7C] Example 11 Example 12 Example 13 Example 14 Example 15 Coating composition 11 Coating composition 12 Coating composition 13 Coating composition 14 Coating composition 15 Hydroxyl group-containing resin (A) (A1) (A1) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B1) (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C11) (C11) (C11) (C11) (C11) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D2) (D3) (D4) Alkanolamine (E) (E1) (E1) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 1.5 1.5 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 4.0 6.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O O O O O Storage stability Viscosity ratio (%) 110 110 140 140 140 Solvent resistance 4 3 5 5 4 Processability Folding test 5 5 5 4 5 Adhesive property 5 5 5 4 4 Alkali resistance 8FM 8FM 8FM 8F 8FM Acid resistance 8FM 8FM 8FM 8F 8FM 2021347006   28 Aug 2026

[0146] [Table 7D] Example 16 Example 17 Example 18 Example 19 Example 20 Coating composition 16 Coating composition 17 Coating composition 18 Coating composition 19 Coating composition 20 Hydroxyl group-containing resin (A) (A1) (A1) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B1) (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C11) (C11) (C11) (C12) (C13) Phosphoric acid-modified epoxy resin (D) (D5) (D6) (D7) (D1) (D1) Alkanolamine (E) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 1.5 1.5 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O O O O O Storage stability Viscosity ratio (%) 140 140 140 140 140 Solvent resistance 3 4 4 5 5 Processability Folding test 5 4 5 5 5 Adhesive property 4 4 4 5 4 Alkali resistance 8FM 8FM 8FM 8FM 8FM Acid resistance 8FM 8FM 8FM 8FM 8FM 2021347006   28 Aug 2026

[0147] [Table 7E] Example 21 Example 22 Example 23 Example 24 Example 25 Coating composition 21 Coating composition 22 Coating composition 23 Coating composition 24 Coating composition 25 Hydroxyl group-containing resin (A) (A1) (A1) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B1) (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C14) (C15) (C16) (C17) (C18) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) (D1) Alkanolamine (E) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 1.5 1.5 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O O O O O Storage stability Viscosity ratio (%) 140 140 140 150 150 Solvent resistance 5 3 4 5 5 Processability Folding test 4 5 4 4 4 Adhesive property 4 4 4 4 4 Alkali resistance 8FM 8FM 8FM 8FM 8F Acid resistance 8FM 8FM 8FM 8FM 8F 2021347006   28 Aug 2026

[0148] [Table 7F] Example 26 Example 27 Example 28 Example 29 Example 30 Coating composition 26 Coating composition 27 Coating composition 28 Coating composition 29 Coating composition 30 Hydroxyl group-containing resin (A) (A1) (A1) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B1) (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C21) (C22) (C23) (C24) (C25) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) (D1) Alkanolamine (E) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 1.5 1.5 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O O O O O Storage stability Viscosity ratio (%) 140 140 140 150 150 Solvent resistance 5 5 5 4 3 Processability Folding test 5 5 4 5 5 Adhesive property 5 5 4 4 4 Alkali resistance 8FM 8FM 8FM 8FM 8FM Acid resistance 8FM 8FM 8FM 8FM 8FM 2021347006   28 Aug 2026

[0149] [Table 7G] Example 31 Example 32 Example 33 Example 34 Example 35 Coating composition 31 Coating composition 32 Coating composition 33 Coating composition 34 Coating composition 35 Hydroxyl group-containing resin (A) (A1) (A1) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B1) (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C26) (C27) (C28) (C21) (C21) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) (D1) Alkanolamine (E) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 5.0 10.0 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O O O O O Storage stability Viscosity ratio (%) 140 150 150 140 140 Solvent resistance 3 5 5 5 5 Processability Folding test 5 4 4 5 4 Adhesive property 4 4 4 5 5 Alkali resistance 8FM 8FM 8F 8FM 8FM Acid resistance 8FM 8FM 8F 8FM 8FM 2021347006   28 Aug 2026

[0150] [Table 7H] Example 36 Example 37 Example 38 Example 39 Example 40 Coating composition 36 Coating composition 37 Coating composition 38 Coating composition 39 Coating composition 40 Hydroxyl group-containing resin (A) (A2) (A3) (A4) (A5) (A6) Polyester resin 2 Polyester resin 3 Polyester resin 4 Polyester resin 5 Polyester resin 6 Amino resin (B) or other material (B1) (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C11) (C11) (C11) (C11) (C11) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) (D1) Alkanolamine (E) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 1.5 1.5 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O O O O O Storage stability Viscosity ratio (%) 140 140 140 140 140 Solvent resistance 5 5 5 5 5 Processability Folding test 5 4 4 4 4 Adhesive property 5 5 5 5 5 Alkali resistance 8FM 8FM 8FM 8FM 8FM Acid resistance 8FM 8FM 8FM 8FM 8FM 2021347006   28 Aug 2026

[0151] [Table 7I] Example 41 Example 42 Example 43 Example 44 Example 45 Coating composition 41 Coating composition 42 Coating composition 43 Coating composition 44 Coating composition 45 Hydroxyl group-containing resin (A) (A7) (A8) (A9) (A10) (A11) Polyester resin 7 Polyester resin 8 Polyester resin 9 Polyester resin 10 Polyester resin 11 Amino resin (B) or other material (B1) (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C11) (C11) (C11) (C11) (C11) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) (D1) Alkanolamine (E) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 1.5 1.5 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O O O O O Storage stability Viscosity ratio (%) 140 140 140 140 140 Solvent resistance 5 4 3 4 3 Processability Folding test 4 5 5 5 5 Adhesive property 4 4 4 4 4 Alkali resistance 8FM 8FM 8FM 8FM 8FM Acid resistance 8FM 8FM 8FM 8FM 8FM 2021347006   28 Aug 2026

[0152] [Table 7J] Example 46 Example 47 Example 48 Example 49 Example 50 Coating composition 46 Coating composition 47 Coating composition 48 Coating composition 49 Coating composition 50 Hydroxyl group-containing resin (A) (A12) (A13) (A1) (A1) (A1) Epoxy resin 1 Acrylic resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B1) (B1) (B2) (B3) (B4) Covalently bonded blocked acid catalyst (C) or other material (C11) (C11) (C11) (C11) (C11) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) (D1) Alkanolamine (E) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 1.5 1.5 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O O O O O Storage stability Viscosity ratio (%) 140 140 140 140 140 Solvent resistance 3 3 5 4 4 Processability Folding test 4 4 5 5 5 Adhesive property 4 4 5 5 4 Alkali resistance 8FM 8FM 8FM 8FM 8FM Acid resistance 8FM 8FM 8FM 8FM 8FM 2021347006   28 Aug 2026

[0153] [Table 7K] Example 51 Example 52 Example 53 Example 54 Example 55 Coating composition 51 Coating composition 52 Coating composition 53 Coating composition 54 Coating composition 55 Hydroxyl group-containing resin (A) (A1) (A1) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B5) (B6) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C11) (C11) (C11) (C11) (C11) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) (D1) Alkanolamine (E) (E2) (E3) (E4) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 1.5 1.5 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 3.0 3.0 3.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O O O O O Storage stability Viscosity ratio (%) 140 140 110 130 120 Solvent resistance 3 3 5 4 5 Processability Folding test 4 4 5 5 5 Adhesive property 4 4 5 5 5 Alkali resistance 8FM 8FM 8FM 8FM 8FM Acid resistance 8FM 8FM 8FM 8FM 8FM 2021347006   28 Aug 2026

[0154] [Table 7L] Example 56 Example 57 Example 58 Example 59 Example 60 Coating composition 56 Coating composition 57 Coating composition 1 Coating composition 1 Coating composition 1 Hydroxyl group-containing resin (A) (A1) (A1) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B1) (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C11) (C11) (C11) (C11) (C11) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) (D1) Alkanolamine (E) (E5) (E6) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 1.5 1.5 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 180 170 270 Baking time (s) 6 6 6 6 6 Coating film appearance O O O O O Storage stability Viscosity ratio (%) 120 130 140 140 140 Solvent resistance 5 4 4 3 5 Processability Folding test 5 5 5 5 5 Adhesive property 5 5 4 4 4 Alkali resistance 8FM 8FM 8FM 8FM 8FM Acid resistance 8FM 8FM 8FM 8FM 8FM 2021347006   28 Aug 2026

[0155] [Table 7M] Example 61 Example 62 Example 63 Example 64 Coating composition 1 Coating composition 1 Coating composition 1 Coating composition 1 Hydroxyl group-containing resin (A) (A1) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C11) (C11) (C11) (C11) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) Alkanolamine (E) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 1.5 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 280 220 220 220 Baking time (s) 6 1 10 25 Coating film appearance O O O O Storage stability Viscosity ratio (%) 140 140 140 140 Solvent resistance 5 5 5 5 Processability Folding test 4 5 5 5 Adhesive property 4 5 5 5 Alkali resistance 8FM 8FM 8FM 8FM Acid resistance 8FM 8FM 8FM 8FM 2021347006   28 Aug 2026

[0156] [Table 7N] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Coating composition 58 Coating composition 59 Coating composition 60 Coating composition 61 Coating composition 62 Hydroxyl group-containing resin (A) (A1) (A1) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B1) (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C11) (C11) (C11) (C11) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) (D1) Alkanolamine (E) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 95.0 50.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 5.0 50.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 0.5 0.0 15.0 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 3.0 3.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O x O O x Storage stability Viscosity ratio (%) 140 140 140 140 140 Solvent resistance 1 5 1 1 5 Processability Folding test 5 2 5 4 2 Adhesive property 4 2 4 1 2 Alkali resistance 8M 8F 8M 8D 8F Acid resistance 8M 8F 8M 8D 8F 2021347006   28 Aug 2026

[0157] [Table 7O] Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Coating composition 63 Coating composition 64 Coating composition 65 Coating composition 66 Coating composition 67 Hydroxyl group-containing resin (A) (A1) (A1) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material (B1) (B1) (B1) (B1) (B1) Covalently bonded blocked acid catalyst (C) or other material (C11) (C11) (C11) (c31) (c32) Phosphoric acid-modified epoxy resin (D) (D1) (D1) (D1) (D1) Alkanolamine (E) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 1.5 1.5 0.0 0.0 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 0.5 0.0 15.0 3.0 3.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 220 220 220 Baking time (s) 6 6 6 6 6 Coating film appearance O O x x x Storage stability Viscosity ratio (%) 140 140 140 200 250 Solvent resistance 1 1 5 2 1 Processability Folding test 5 4 2 5 5 Adhesive property 4 1 2 2 2 Alkali resistance 8M 8D 8F 8D 8D Acid resistance 8M 8D 8F 8D 8D 2021347006   28 Aug 2026

[0158] [Table 7P] Comparative Example 11 Comparative Example 12 Reference Example 1 Coating composition 68 Coating composition 69 Coating composition 69 Hydroxyl group-containing resin (A) (A1) (A1) (A1) Polyester resin 1 Polyester resin 1 Polyester resin 1 Amino resin (B) or other material Polyisocyanate compound 1 (B5) (B5) Covalently bonded blocked acid catalyst (C) or other material (C11) - - Phosphoric acid-modified epoxy resin (D) (D1) - - Alkanolamine (E) Part(s) by mass (solid content) of (A) per 100 parts by mass of solid content of (A) and (B) 70.0 70.0 70.0 Part(s) by mass (solid content) of (B) per 100 parts by mass of solid content of (A) and (B) 30.0 30.0 30.0 Part(s) by mass (active ingredient) of acid catalyst part of (C) per 100 parts by mass of solid content of (A) and (B) 1.5 0.0 0.0 Part(s) by mass (solid content) of (D) per 100 parts by mass of solid content of (A) and (B) 3.0 0.0 0.0 Part(s) by mass (active ingredient) of (E) per 100 parts by mass of solid content of (A) and (B) 0.0 0.0 0.0 Baking temperature (PMT) (°C) 220 220 220 Baking time (s) 6 6 25 Coating film appearance O x O Storage stability Viscosity ratio (%) 150 150 150 Solvent resistance 1 1 5 Processability Folding test 3 2 5 Adhesive property 1 2 5 Alkali resistance 8D 8D 8FM Acid resistance 8D 8D 8FM

[0159] <Evaluation items> 1) Storage stability Evaluation was carried out using a Ford cup No. 4 (manufactured by Ueshima Seisakusho Co., Ltd.) in accordance with the method specified in JIS K 5600-2-2 (the flow cup method). The coating compositions obtained in Examples, Comparative Examples, and Reference Example were each stirred at 1,000 rpm for 3 minutes using a disper. Immediately after stirring, a cup was filled up with the coating material such that air 2021347006   28 Aug 2026 bubbles did not enter in the coating material. At this time, the lower flow outlet (orifice) was pressed so that the coating material did not leak from the outlet. Thereafter, the presser was removed and measurement of time was started with a stopwatch at the same time as the coating material flowed down. When the flow down from the lower flow outlet (orifice) turned to a discontinuous flow, the stopwatch was stopped and the number of seconds at that time was read, and the time was recorded (initial viscosity). The temperature of the coating composition was adjusted to 25°C. Each of the coating compositions of Examples, Comparative Examples, and Reference Examples whose initial viscosity had been measured was charged into a 1 / 5 L can to 80 to 90%, sealed, and then allowed to stand in a thermostatic chamber at 50°C. Thereafter, the sample was taken out after 28 days, and the viscosity was measured in the same manner as described above (viscosity over time). The ratio of the viscosity over time to the initial viscosity (viscosity ratio) was calculated from the following formula and the storage stability was evaluated. When the viscosity ratio was 150% or less, it was determined that the storage stability was good. Viscosity ratio (%) = viscosity over time / initial viscosity x 100

[0160] 2) Coating film appearance The appearance of the coating films obtained in Examples, Comparative Examples, and Reference Example was visually observed, and the degree of bubbles was evaluated according to the following criteria. O: No bubbles were generated in the coating film. x: Bubbles were generated in the coating film. 2021347006   28 Aug 2026 3) Solvent resistance The coated steel sheets obtained in Examples, Comparative Examples, and Reference Example were attached to an evaluation table of an abrasion resistance tester IMC-155F (manufactured by Imoto Machinery Co., Ltd.) with an adhesive tape, and a rubbing test was carried out. Under the measurement conditions, absorbent cotton containing methyl ethyl ketone and wrapped with four gauzes was used as an abrasion material, a load was set to 2 kgf, a reciprocating speed was set to 30 times / min, a reciprocating distance was set to 70 mm, and the number of reciprocations was set to 200 times. The number of rubbing reciprocations until the substrate of the base steel sheet was exposed was counted and evaluated according to the following criteria. Score 3 or higher was regarded as acceptable, and score 5 was regarded as good. The test condition was adjusted to a temperature of 23°C and a humidity of 60 RH%. Score 5: 200 times or more Score 4: 100 times or more and less than 200 times Score 3: 50 times or more and less than 100 times Score 2: 10 times or more and less than 50 times Score 1: less than 10 times

[0162] 4) Processability (folding test) Each of the coated steel sheets obtained in Examples, Comparative Examples, and Reference Example was cut into a size of 5 cm x 3 cm, and subjected to preliminary folding using a seam folding machine (manufactured by Ueshima Seisakusho Co., Ltd.) such that the coated film surface was on the front side. Five steel sheets having the same thickness (0.4 mm) were sandwiched between the test pieces, and folded by a pressing machine (manufactured by Kyoritsu Kogyo Co., Ltd.). The state (crack) of 2021347006   28 Aug 2026 the coating film of the processed part was observed with a loupe of 15 magnification, and the processability was evaluated according to the following criteria. Score 4 or higher was regarded as acceptable. The test condition was adjusted to a temperature of 23°C and a humidity of 60 RH%. 5: No crack is observed in the processed part. 4: Cracks are observed in less than 20% (and more than 0%) of the area of the processed part. 3: Cracks are observed in 20% or more and less than 50% of the area of the processed part. 2: Cracks are observed in 50% or more and less than 80% of the area of the processed part. 1: Cracks are observed in 80% or more of the area of the processed part.

[0163] 5) Processability (adhesive property) Each of the coated steel sheets obtained in Examples, Comparative Examples, and Reference Example was cut into a size of 5 cm x 3 cm, and subjected to preliminary folding using a seam folding machine (manufactured by Ueshima Seisakusho Co., Ltd.) such that the coated film surface was on the front side. Two steel sheets having the same thickness (0.4 mm) were sandwiched between the test pieces, and folded by a pressing machine (manufactured by Kyoritsu Kogyo Co., Ltd.). Cellophane tape (trademark) (LP-24, manufactured by NICHIBAN Co., Ltd.) was brought into close contact with the processed part of the coated steel sheet, and peeled off at once. The appearance of the part peeled off with the tape was observed with a loupe of 15 magnification, and the processing adhesive property was evaluated according to the following criteria. Score 4 or higher was regarded as acceptable. The test condition 2021347006   28 Aug 2026 was adjusted to a temperature of 23°C and a humidity of 60 RH%. 5: The metal substrate is not observed in the tape peeled part. 4: The metal substrate is observed in less than 20% (more than 0%) of the area of the tape peeled part. 3: The metal substrate is recognized in 20% or more and less than 50% of the area of the tape peeled part. 2: The metal substrate is recognized in 50% or more and less than 80% of the area of the tape peeled part. 1: Metal basis material is recognized in 80% or more of the area of the tape peeled portion.

[0164] 6) Alkali resistance test Each of the coated steel sheets obtained in Examples, Comparative Examples, and Reference Example was cut into a size of 5 cm x 10 cm, and each specimen was immersed in a 5% aqueous sodium hydroxide solution at 23°C for 48 hours, taken out, washed with water, and dried at 20°C for 2 hours. The resulting coated steel sheet specimen was evaluated for blister on a flat portion in accordance with ASTM D714-56. Here, ASTM D714-56 evaluates the size (mean diameter) and density of each blister in comparison with a standard judgment photograph and indicates a grade symbol. The size was classified in four grades in the order of 8 (diameter: about 1 mm), 6 (diameter: about 2 mm), 4 (diameter: about 3 mm) and 2 (diameter: about 5 mm), and the density was classified in five grades in the ascending order of F, FM, M, MD and D, and when there was no blister, this was evaluated as 10. A score of 8FM or more was defined to be acceptable. 2021347006   28 Aug 2026 7) Acid resistance test Each of the coated steel sheets obtained in Examples, Comparative Examples, and Reference Example was cut into a size of 5 cm x 10 cm, and each specimen was immersed in a 5% aqueous sulfuric acid solution at 23°C for 48 hours, taken out, washed with water, and dried at 20°C for 2 hours. The resulting coated steel sheet specimen was visually observed for blister on a flat portion in accordance with ASTM D714-56 and the acid resistance was evaluated. A score of 8FM or more was defined to be acceptable.

[0166] As shown in the above tables, in Examples 1 to 64, the storage stability of the coating composition was good. In Examples 1 to 57 among Examples, a coating film was formed at a baking temperature of 220°C for a baking time of 6 seconds. In these Examples, a coating film having good physical properties in all of coating appearance, solvent resistance, folding processability, processing adhesive property, alkali resistance, and acid resistance was obtained. Examples 62, 1, 63, and 64 are examples in which the baking temperature was 220°C and the baking time was 1 second, 6 seconds, 10 seconds, and 25 seconds, respectively. In Example 62, although the baking time was set to 1 second, a coating film having good physical properties was obtained, and it was confirmed that the coating composition was sufficiently cured even in a short time of 1 second. In Example 63, the baking time was 10 seconds, and in Example 64, the baking time was 25 seconds. Also in these Examples, a coating film having good physical properties was obtained. That is, it was found that when the coating composition of the present invention is used, the coating composition is sufficiently cured even in a short time, and 2021347006   28 Aug 2026 a coating film obtained by short-time baking (Examples 62, 1, 63) has the same good physical properties as a coating film obtained by relatively long-time baking (Example 64). Examples 58, 59, 1, 60, and 61 are examples in which the baking time was set to 6 seconds and the baking temperatures were set to 180°C, 170°C, 220°C, 270°C, and 280°C, respectively. For example, in Examples 58 and 59, although a coating film was formed at a low baking temperature, a coating film having good physical properties was obtained, and it has been confirmed that the coating composition of the present invention was sufficiently cured even when baked at a low temperature. In Examples 60 and 61, a coating film was formed at a relatively high baking temperature, and it has been confirmed that the coating composition of the present invention can afford a coating film having good physical properties.

[0167] In Comparative Examples 1 to 12, it is shown that the storage stability of the coating composition and the curing in a short time are not compatible. Hereinafter, each comparative example will be described in detail. The coating composition of Comparative Example 1 contains 95 parts by mass of the hydroxyl group-containing resin (A1) and 5 parts by mass of the amino resin (B1) based on 100 parts by mass of the total of the hydroxyl group-containing resin (A1) and the amino resin (B1). The results of solvent resistance, alkali resistance, and acid resistance of the coating film formed in Comparative Example 1 were not good. That is, in Comparative Example 1, it is found that the curing reaction does not sufficiently proceed by heating at 220°C for 6 seconds and a coating film having good physical properties is not obtained. The coating composition in Comparative Example 2 contains 50 parts by mass 2021347006   28 Aug 2026 of the hydroxyl group-containing resin (A1) and 50 parts by mass of the amino resin (B1) based on 100 parts by mass of the total of the hydroxyl group-containing resin (A1) and the amino resin (B1). The coating film formed in Comparative Example 2 was unsatisfactory in coating film appearance, folding processability, and processing adhesive property. That is, in Comparative Example 2, it is found that the curing reaction does not appropriately proceed by heating at 220°C for 6 seconds and a coating film having good physical properties is not obtained. The coating composition in Comparative Example 3 has a small content of the covalently bonded blocked acid catalyst (C11), and the coating composition in Comparative Example 5 has a large content of the covalently bonded blocked acid catalyst (C11). The coating film formed in Comparative Example 3 was unsatisfactory in solvent resistance, alkali resistance, and acid resistance, and the coating film formed in Comparative Example 5 was unsatisfactory in coating appearance, folding processability, and processing adhesive property. That is, in Comparative Examples 3 and 5, it is found that an appropriate curing reaction does not proceed by heating at 220°C for 6 seconds and a coating film having good physical properties is not obtained. The coating composition in Comparative Example 4 does not contain a covalently bonded blocked acid catalyst (C). The coating film formed in Comparative Example 4 exhibited poor results in solvent resistance, processing adhesive property, alkali resistance, and acid resistance. That is, in Comparative Example 4, it is found that the curing reaction does not sufficiently proceed by heating at 220°C for 6 seconds and a coating film having good physical properties is not obtained. The coating composition in Comparative Example 6 has a low content of the phosphoric acid-modified epoxy resin (D1), and the coating composition in Comparative Example 8 has a high content of the phosphoric acid-modified epoxy resin 2021347006   28 Aug 2026 (D1). The coating film formed in Comparative Example 6 was unsatisfactory in solvent resistance, alkali resistance, and acid resistance, and the coating film formed in Comparative Example 8 was unsatisfactory in coating film appearance, folding processability, and processing adhesive property. That is, in Comparative Examples 6 and 8, it is found that an appropriate curing reaction does not proceed by heating at 220°C for 6 seconds and a coating film having good physical properties is not obtained. The coating composition in Comparative Example 7 does not contain any phosphoric acid-modified epoxy resin (D). The coating film formed in Comparative Example 7 exhibited poor results in solvent resistance, processing adhesive property, alkali resistance, and acid resistance. That is, in Comparative Example 7, it is found that the curing reaction does not sufficiently proceed by heating at 220°C for 6 seconds and a coating film having good physical properties is not obtained. The coating composition in Comparative Example 9 contains an amine blocked acid catalyst (acid catalyst 1 (c31)) as an acid catalyst, and the coating composition in Comparative Example 10 contains an unblocked sulfonic acid (acid catalyst 2 (c32)) as an acid catalyst. In these Comparative Examples, the viscosity of the coating composition increased, and the formed coating film had poor appearance, solvent resistance, processability adhesive property, alkali resistance, and acid resistance. That is, in Comparative Examples 9 and 10, the storage stability of the coating composition significantly deteriorated, and in the formation of a coating film, the curing reaction did not appropriately proceed by heating at 220°C for 6 seconds, and a coating film having good physical properties was not obtained. In Comparative Example 10, it is considered that the sulfonic acid acted as a curing catalyst during storage, so that the viscosity of the coating composition increased. In Comparative Example 9, it is considered that the amine compound blocking the sulfonic acid dissociated from the 2021347006   28 Aug 2026 sulfonic acid during storage, and the sulfonic acid acted as a curing catalyst. In general, in the curing process of a coating film, the solvent evaporates from the applied film and then the coating film starts to be cured. In Comparative Examples 9 and 10, it is considered that in the curing process of the coating film, the catalyst worked to accelerate the curing before the evaporation of the solvent completed, so that pinholeshaped holes called bubbles were generated in the coating film appearance after the curing. It is considered that these bubbles caused exposure of the substrate in the solvent resistance test and peeling of the coating film in the processing adhesive property test. The coating composition in Comparative Example 11 contains not an amino resin but a polyisocyanate compound as a curing agent. The coating film formed in Comparative Example 11 exhibited poor results in solvent resistance, processing adhesive property, alkali resistance, and acid resistance. That is, in Comparative Example 11, it is found that the curing reaction does not sufficiently proceed by heating at 220°C for 6 seconds and a coating film having good physical properties is not obtained. When an amino resin is used as in Examples, it is considered that in addition to a curing reaction with a hydroxyl group-containing resin or a phosphoric acid-modified epoxy resin in the presence of an acid catalyst, self-condensation also occurs, and the overall curing reaction proceeds sufficiently. However, when an isocyanate compound was used as in Comparative Example 11, it is considered that a curing reaction with a hydroxyl group-containing resin and a phosphoric acid-modified epoxy resin occurred, but a self-condensation reaction did not occur, and the overall curing reaction did not sufficiently proceed. In addition, since the polyisocyanate compound is blocked with the blocking agent, the blocking agent needs to dissociate before the reaction of isocyanate in order for the curing reaction to proceed, but it is considered 2021347006   28 Aug 2026 that the blocking agent could not sufficiently dissociate in a short time of 6 seconds, and the curing reaction did not proceed.

[0168] In Reference Example 1, a common coating composition for a precoated steel sheet was used. This coating composition contains neither the covalently bonded blocked acid catalyst (C) nor the phosphoric acid-modified epoxy resin (D). The coating composition in Reference Example 1 exhibited good evaluation of storage stability, and a coating film having good physical properties has been obtained by heating the coating composition at a baking temperature of 200°C for 25 seconds. In Comparative Example 12, the coating composition in Reference Example 1 was heated at a baking temperature of 220°C for 6 seconds. The coating film formed in Comparative Example 12 was unsatisfactory in coating film appearance, solvent resistance, folding processability, processing adhesive property, alkali resistance, and acid resistance. That is, in Comparative Example 12, it is found that the curing reaction does not sufficiently proceed by heating at a baking temperature of 220°C for 6 seconds and a coating film having good physical properties is not obtained. INDUSTRIAL APPLICABILITY

[0169] The coating composition of the present disclosure has good storage stability, a curing reaction thereof proceeds by baking in a short time, so that a coating film having good physical properties can be formed even by baking in a short time. In the coating composition of the present disclosure, the curing reaction proceeds well even in a furnace having a shortened furnace length like an IH type furnace, and a coating film having good physical properties can be formed. 2021347006   28 Aug 2026

[0170] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0171] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims

2021347006   28 Aug 2026THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS1.      A coating composition comprisinga hydroxyl group-containing resin (A),an amino resin (B),a covalently bonded blocked acid catalyst (C),a phosphoric acid-modified epoxy resin (D), andan alkanolamine (E)whereinbased on 100 parts by mass of a total of a resin solid content of the hydroxyl group-containing resin (A) and a resin solid content of the amino resin (B),60 to 90 parts by mass of the hydroxyl group-containing resin (A),10 to 40 parts by mass of the amino resin (B),1 to 10 parts by mass of an acid catalyst moiety of the covalently bonded blocked acid catalyst (C), and1 to 10 parts by mass of a solid component of the phosphoric acid-modified epoxy resin (D) are contained.

2. The coating composition according to claim 1, wherein a number-averagemolecular weight of the phosphoric acid-modified epoxy resin (D) is in a range of 460 to 4,000.

3. The coating composition according to claim 1 or 2, wherein the covalentlybonded blocked acid catalyst (C) is a catalyst in which an aromatic sulfonic acid is blocked by a compound having a glycidyl group.2021347006   28 Aug 20264.      The coating composition according to claim 3, wherein in the covalentlybonded blocked acid catalyst (C), the compound having a glycidyl group is an epoxy resin having two or more glycidyl groups in a molecule or a glycidyl ether compound having one glycidyl group in a molecule.

5. The coating composition according to claim 4, wherein in the covalentlybonded blocked acid catalyst (C), a number-average molecular weight of the epoxy resin having two or more glycidyl groups in a molecule is in a range of 2,000 to 7,000.

6. The coating composition according to claim 4, wherein in the covalentlybonded blocked acid catalyst (C), a molecular weight of the glycidyl ether compound having one glycidyl group in a molecule is in a range of 140 to 200.

7. The coating composition according to any one of claims 1 to 6, wherein thehydroxyl group-containing resin (A) is a polyester resin anda number-average molecular weight of the hydroxyl group-containing resin (A) is in a range of 1,500 to 5,000 and a hydroxyl value is in a range of 40 to 100 mg KOH / g.

8. The coating composition according to any one of claims 1 to 7, wherein theamino resin (B) comprises a melamine resin.

9. The coating composition according to any one of claims 1 to 8, wherein thealkanolamine (E) comprises two or more alkanol groups in a molecule.2021347006   28 Aug 202610.     The coating composition according to any one of claims 1 to 8, wherein acontent of the alkanolamine (E) is 1.0 to 4.0 parts by mass based on 100 parts by mass of the total of the resin solid content of the hydroxyl group-containing resin (A) and the resin solid content of the amino resin (B).

11. A method for producing a coating film, comprising:a step of applying the coating composition according to any one of claims 1 to10 to an article to be coated to form an applied film; anda step of drying and / or curing the applied film under a condition in which a peak temperature of the article to be coated is 180°C to 270°C and a drying and / or curing time is 1 to 10 seconds.

12. A method for producing a precoated metal sheet, comprising:a step of applying the coating composition according to any one of claims 1 to10 on at least one surface of a metal sheet to form an applied film such that a film thickness after curing is 5 to 25 pm; anda step of drying and / or curing the applied film under a condition in which a peak temperature of the metal sheet is 180°C to 270°C and a drying and / or curing time is 1 to 10 seconds.