JP2002167545A - Corrosionproof coating material composition for single- coating finishing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a corrosionproof coating material composition for single- coating finishing capable of forming a coating film having excellent corrosionproofness and weatherability at normal temperatures and, simultaneously, by a single-coating step in order to maintain the corrosionproofness and the beauty of a structure made of steel. SOLUTION: This corrosionproof coating material composition for single- coating finishing comprises (A) an acrylic resin, (B) an epoxy resin having at least two epoxy groups, and (C) an amine curing agent and, at the same time, the above acrylic resin (A) contains (a) a cycloalkyl group-containing unsaturated monomer as a copolymer component, and as the compounding ratios of the acrylic resin (A) and the epoxy resin (B), the component (A) is 30-70 wt.% and the component (B) is 30-70 wt.%, each based on the total amount of the solid contents of these resins.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel tower structure for power transmission and communication, a container for transportation, a ship, a bridge, a tank, and other steel structures. Can form a coated film at room temperature and in one coating process.
The present invention relates to an anticorrosion paint composition for a first-coat finish.

[0002]

BACKGROUND OF THE INVENTION Transmission and telecommunication tower structures, transport containers, ships, bridges,
In steel structures such as tanks, anticorrosion coating is applied to prevent corrosion and maintain aesthetic appearance. Conventionally, as a room temperature curable epoxy resin composition having excellent anticorrosion properties, a composition comprising an epoxy resin represented by polyglycidyl ether and a cured product of polyamine, polyamidoamine, etc. is widely known from the viewpoint of adhesion and anticorrosion properties. However, this coating composition tends to have poor weather resistance. On the other hand, for the purpose of cosmetics, room-temperature-curable polyurethane resin compositions, acrylic silicone resin compositions, and fluororesin compositions having excellent weather resistance have been applied, but these are inferior in adhesion and corrosion resistance. However, it cannot be applied directly to a steel sheet, and usually has to be applied on a primer coating such as an epoxy resin coating. Furthermore, in order to maintain the desired performance, at least three or more coating steps are required to apply the undercoat paint a plurality of times, add an intermediate coat, and further include a top coat, especially, When painting an existing steel structure, it is necessary to work in high places without scaffolding, and to reduce the number of paintings as much as possible because labor costs and scaffolding account for more than 80% of the painting cost. Shortening the painting process has been strongly demanded from the viewpoint of safety and economy.

[0003]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above problems, and as a result, have found that a main agent containing a specific acrylic resin (A) and an epoxy resin (B) and an amine curing agent (C ) Was found to be able to form a coating film excellent in both corrosion resistance and weather resistance in a single coating step, and completed the present invention. That is, the present invention provides a coating composition comprising: 1, an acrylic resin (A), an epoxy resin (B) having at least two epoxy groups, and an amine curing agent (C) containing an aminosilane. ) Contains a cycloalkyl group-containing unsaturated monomer (a) as a copolymer component, and the mixing ratio of the acrylic resin (A) and the epoxy resin (B) is based on the total of these resin solids. (A) is 30 to 70% by weight, and (B) is 30 to 70% by weight.
2. The anticorrosion coating composition for a single coating finish according to item 1, wherein the acrylic resin (A) contains an epoxy group-containing unsaturated monomer (b) as a copolymer component. The one-coat finish according to claim 1 or 2, wherein the acrylic resin (A) contains an ultraviolet-absorbing unsaturated monomer (c) and / or an ultraviolet-stable unsaturated monomer (d) as a copolymer component. Anticorrosion coating composition for use, 4. The weight average molecular weight of the epoxy resin (B) is 200 to
Item 4. The anticorrosion paint composition for a one-time coating finish according to any one of Items 1 to 3, which is 3,000. 5. An anticorrosion coating composition for a one-coat finish, which further comprises an ultraviolet absorber (D) and / or an ultraviolet stabilizer (E) to the coating composition according to any one of the above items 1 to 4.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION The anticorrosion paint composition for a single coating finish of the present invention is obtained by mixing an amine curing agent (C) immediately before use with a base material containing an acrylic resin (A) and an epoxy resin (B). This is a room temperature curable two-pack type coating composition.

First, the main ingredient will be described. In the present invention, the acrylic resin (A) contains a cycloalkyl group-containing unsaturated monomer (a) as a copolymer component, and contains an unsaturated monomer containing the cycloalkyl group-containing unsaturated monomer (a). It is obtained by subjecting monomers to radical polymerization with a radical polymerization initiator in an organic solvent.

Cycloalkyl group-containing unsaturated monomer (a)
Examples thereof include cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, and the like. These monomers may be used alone or in combination of two or more.

In the present invention, the acrylic resin (A) contains an epoxy group-containing unsaturated monomer (b) as a copolymer component for the purpose of introducing a crosslinking functional group to be reacted with an amine curing agent (C) described later. Is preferred from the viewpoint of improving corrosion resistance and weather resistance.

The epoxy group-containing unsaturated monomer (b) includes glycidyl (meth) acrylate, 3,4-epoxycycyclohexyl (meth) acrylate, β-methylglycidyl (meth) acrylate, and allyl glycidyl ether. No. These can be used alone or by appropriately selecting two or more kinds.

The acrylic resin (A) is further copolymerized with an ultraviolet-absorbing unsaturated monomer (c) and / or an ultraviolet-stable unsaturated monomer (d) for the purpose of improving weather resistance. You may. Examples of the ultraviolet absorbing unsaturated monomer (c) include 2- [2′-hydroxy-5 ′-(methacryloyloxymethyl) phenyl] -2H-benzotriazole and 2- [2′-hydroxy-5 ′ -(Methacryloyloxyethyl) phenyl] 2H-benzotriazole, 2-
[2'-hydroxy-5 '-(methacryloyloxypropyl) phenyl] -2H-benzotriazole, 2- [2'-
Hydroxy-5 '-(methacryloyloxyhexyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-3'-t-butyl-5'-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, -[2'-
Hydroxy-5'-t-butyl-3 '-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, 2- [
2'-hydroxy-5 '-(methacryloyloxyethyl)
Phenyl] -5-chloro-2H-benzotriazole, 2-
[2'-Hydroxy-5 '-(methacryloyloxyethyl) phenyl] -5-methoxy-2H-benzotriazole, 2- [2'-hydroxy-5'-(methacryloyloxyethyl) phenyl] -5-cyano-2H -Benzotriazole, 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -5-t-butyl-2H-benzotriazole, 2- [2'-hydroxy-5'-(methacryloyloxyethyl) Phenyl] -5-nitro-2H-benzotriazole and the like. These may be used alone or by appropriately selecting two or more kinds.

As the UV-stable unsaturated monomer (d), for example, 4- (meth) acryloyloxy-2,2,
6,6-tetramethylpiperidine, 4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine,
-(Meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloylamino-
1,2,2,6,6-pentamethylpiperidine, 4-cyano-
4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,
6-tetramethylpiperidine, 4-crotonoylamino-
2,2,6,6-tetramethylpiperidine and the like. These may be used alone or by appropriately selecting two or more kinds.

Further, in order to increase the crosslink density of the coating film and obtain weather resistance by reacting with an aminosilane contained in the amine curing agent (C), an unsaturated monomer (e) containing an alkoxysilyl group is used together. It may be polymerized. Examples of the alkoxysilyl group-containing unsaturated monomer (e) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-
Methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane and the like. These can be used alone or by appropriately selecting two or more kinds.

Other unsaturated monomers (f) copolymerizable therewith other than the above (a) to (e) include, for example,
Methyl (meth) acrylate, ethyl (meth) acrylate, n-, i-, t-butyl (meth) acrylate,
C1-C24 alkylester such as acrylic acid or methacrylic acid such as 2-ethylhexyl (meth) acrylate or the like, methoxymethyl acrylate, methoxyethyl acrylate or the like; hydroxyethyl (meth) acrylate; A) hydroxyl-containing monomers such as acrylate and hydroxypropyl (meth) acrylate; carboxyl-containing monomers such as acrylic acid and methacrylic acid; styrene, (meth) acrylamide, and vinyl acetate. These can be used alone or by appropriately selecting two or more kinds.

The organic solvent used for synthesizing the acrylic resin (A) is not particularly limited. Examples thereof include aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and butyl acetate and the like. Ester solvents, alcohol solvents such as isopropanol, mineral spirits, aliphatic hydrocarbons such as n-hexane, n-octane, 2,2,2-trimethylpentane, isooctane, n-nonane, cyclohexane, methylcyclohexane, etc. Is mentioned. These may be used alone or in combination. Although the polymerization initiator is not particularly limited, azobisisobutyronitrile, 2,2-azobis (2-methylbutyronitrile),
2,2-azobis (2-methylpropionitrile),
Azo initiators such as 2,2-azobis (2,4-dimethylvaleropnitrile), benzoyl peroxide, t-
Peroxide systems such as butylperoxyoctanoate, diisobutyl peroxide, di (2-ethylhexylperoxypivalate), and decanoyl peroxide can be used.

The acrylic resin (A) obtained as described above has a weight average molecular weight of 1,000 to 100,000.
0, preferably 2000 to 50,000.
If it is less than 1,000, the weather resistance decreases, while 100,00
If it exceeds 0, the compatibility with the epoxy resin (B) and the amine curing agent (C) deteriorates, which is not preferable.

The acrylic resin (A) has a solubility parameter (hereinafter referred to as SP value) of 8 to 10, preferably 8.5 to 10.
9.5 is preferred. If it is less than 8, the compatibility with the epoxy resin (B) is insufficient, which is not preferable.

The epoxy resin (B) has at least two or more epoxy groups in one molecule. Examples of such an epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, hydrogenated bisphenol A type epoxy resin, alicyclic epoxy resin, and polyglycol type epoxy resin. Epoxy resin (B)
Has a weight average molecular weight of about 200 to about 3,000,
Preferably, it is in the range of about 300 to about 1,000. If the weight-average molecular weight is less than 200, the anticorrosion property is reduced, and if it exceeds 3,000, the compatibility with other resins becomes poor, which is not preferable.

As the epoxy resin (B), specifically,
“Epicoat 828”, “Epicoat 830”, “Epicoat 834”, “Epicoat 806H” (manufactured by Yuka Shell),
"DER-331J" (manufactured by Dow Chemical Company), "AER
260 "(manufactured by Asahi Kasei Epoxy)," ST-3000 ",
"ST-5080" (manufactured by Toto Kasei), "Epomic R #
140P "(manufactured by Mitsui Chemicals, Inc.)," ERL-4221 "," E
Commercially available products such as "RL-4229" (manufactured by Union Carbide), "Denacol EX-830" (manufactured by Nagase Kasei Kogyo), and "Haripol EP-450" (manufactured by Harima Kasei) can be used.

In the present invention, an acrylic-modified epoxy resin obtained by reacting at least part or all of the above-mentioned acrylic resin (A) and epoxy resin (B) can also be used. As a method for synthesizing such an acrylic-modified epoxy resin, for example, a method in which a monomer having a carboxyl group is copolymerized with the acrylic resin (A) and at least one part or all reacts with the epoxy group contained in the epoxy resin (B) may be mentioned. Can be In such a reaction, a reaction catalyst of an epoxy group and a carboxyl group may be used, for example, tetraethylammonium bromide, tetrabutylammonium bromide, tetraethylammonium chloride, tetrabutylphosphonium bromide,
Examples thereof include quaternary salt catalysts such as triphenylbenzylphosphonium chloride and amines such as triethylamine and tributylamine.

In the present invention, the mixing ratio of the acrylic resin (A) and the epoxy resin (B) is 30 to 70% by weight, preferably 40% by weight, based on the total of these resin solids.
60% by weight, (B) 30-70% by weight, preferably 4%
0 to 60% by weight.

If the blending ratio of the acrylic resin (A) is less than 30% by weight, it is not preferable because the weather resistance is lowered and the drying property after coating is lowered. On the other hand, if it exceeds 70% by weight, the corrosion resistance is undesirably reduced. If the blending ratio of the epoxy resin (B) is less than 30% by weight, the anticorrosion property is reduced, and if it is more than 70% by weight, the weather resistance is undesirably reduced.

Although the coating composition of the present invention can be used as a clear coating, it can also be used as an enamel coating by blending pigments such as coloring pigments, extender pigments and rust preventive pigments. These pigments include titanium dioxide, carbon black, lamp black, zinc oxide, iron oxide, toluidine, benzine yellow, phthalocyanine blue, phthalocyanine green, and carbazole violet,
Crystalline silica, barium sulfate, magnesium silicate, calcium silicate, mica, mica-like iron oxide, calcium carbonate,
Examples include zinc powder, aluminum, aluminum silicate, gypsum, and feldspar. These can be used alone or in combination of two or more. The mixing ratio of the pigment is preferably 10 to 40 vol% in terms of the pigment volume concentration (PVC). The method for dispersing the pigment is not particularly limited, but is preferably added to the epoxy resin (B), and examples thereof include a method of dispersing the pigment using a ball mill, a sand mill, or the like.

The main ingredient of the coating composition of the present invention can be obtained by mixing the components, and the mixing method and order can be performed without any particular limitation.

Next, the curing agent will be described. The amine curing agent (C) used in the coating composition of the present invention is a curing agent that reacts with the epoxy group in the epoxy resin (B). It also acts as a reaction catalyst when the moisture in the air causes hydrolysis and condensation reactions. In the present invention, the amine curing agent (C) is an amine containing an aminosilane. In particular, a bifunctional amine can be suitably used. Examples of the difunctional amine include an aliphatic or alicyclic polyamine and an epoxy of the polyamine. Resin adducts, ketimines, polyamidoamines, aromatic amines, aliphatic or alicyclic Mannich compounds, and the like can be used alone or in combination of two or more. Specifically, "Sunmide J230N" and "Sunmide I518"
(Manufactured by Sanwa Chemical Industry Co., Ltd.), "Daitoclar B1969"
Commercial products such as (manufactured by Daito Sangyo) can be used.

The aminosilane is represented by the following formula (1) H ₂ NX—Si— (OY) ₃ (1) In the formula, X is an alkyl group, an aryl group, an alkoxyalkyl group, or a cycloalkyl group, and Y is 1
To N-β- (aminoethyl) aminopropyltrimethoxysilane, N-β- (aminoethyl) aminopropyltriethoxysilane, N-phenyl- γ-aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane and the like can be mentioned, and these can be used alone or in combination of two or more. As a commercially available product, for example, “KBM-603”,
"KBE-903" (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. The amine curing agent (C) comprises the bifunctional amine and the aminosilane, and the ratio is preferably 0.1 mol or more of the aminosilane to 1 mol of the bifunctional amine. The aminosilane ratio is 0.1
If the amount is less than mol, weather resistance is undesirably reduced.

In the present invention, the mixing ratio of the amine curing agent (C) is such that the ratio of the number of equivalents of active hydrogen of amino groups / the number of equivalents of epoxy groups contained in the epoxy resin (B) and the acrylic resin (A) is obtained. 0.4-2.0, preferably 0.6
It is suitable from the viewpoints of curability, corrosion resistance, weather resistance and the like of the obtained coating composition.

In the present invention, for the purpose of improving weather resistance, the above-mentioned coating composition is further added with an ultraviolet absorber (D) and / or
Alternatively, it is preferable to include an ultraviolet stabilizer (E). Benzotriazole based as such ultraviolet absorber (D),
Benzophenone-based, oxalic anilide-based, and cyanoacrylate-based products are available.
0 "," Tinuvin 400 "," ASL-23 "," CY
1164L "(above, manufactured by Ciba-Geigy).

As the ultraviolet stabilizer (E), hindered amines are preferable, and as a commercially available product, "Tinuvin 12" is used.
3 "," Tinuvin 144 "," Sanol LS-292 "
(Above, manufactured by Ciba-Geigy).

In the present invention, if necessary, a curing catalyst such as an organotin compound, a thickening agent, an anti-sagging agent, a leveling agent, an antifoaming agent, a dispersing agent, a coating additive such as an organic solvent, etc. It can also be blended with the amine curing agent (C).

The anticorrosive coating composition for a single coating finish of the present invention is applied to a steel sheet surface, a galvanized surface, or an old coating film surface which has been subjected to a base treatment, if necessary. Although the coating method is not particularly limited, for example, it can be performed by means such as spray coating, roller coating, brush coating, flow coating, etc., and the coating film thickness is not particularly limited, but is usually in the range of 60 to 120 μm. Is preferred. The coating composition of the present invention can be cured at room temperature, and the cured product exhibits excellent performance, but may be subjected to forced drying or heat curing.

[0030]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. In the description, "parts" and "%" mean "parts by weight" and "% by weight", respectively, unless otherwise specified.

Examples 1 to 5 and Comparative Examples 1 to 4 Production of paint A pigment dispersion paste was prepared by blending an epoxy resin and a pigment in a ball mill according to the formulation shown in Table 1 and dispersing for 1 hour. The main ingredients were adjusted according to the composition shown in Table 1, and a curing agent was mixed to obtain each paint. In addition, the numbers in Table 1 represent solid contents, and the symbols are as follows.

A1: "U-double S-2818": Nippon Shokubai Co., Ltd., cyclohexyl methacrylate, UV-stable unsaturated monomer copolymerized acrylic resin, solid content 60% A2: "U-double S-2840": Nippon Shokubai Co., Ltd. , Cyclohexyl methacrylate, UV-stable unsaturated monomer copolymerized acrylic resin, solid content 60% A3: "You Double UV-6010": Nippon Shokubai Co., Ltd., cyclohexyl methacrylate, UV-absorbing unsaturated monomer, UV-stable Acrylic resin copolymerizable with unsaturated monomer, solid content 50%.

A4: An acrylic resin (A4) was produced as follows. 280 parts of xylene in the flask, "MOA"
(Trade name, manufactured by Nippo Chemical Co., Ltd., active ingredient, methyl orthoacetate, dehydrating agent) were charged, and the temperature was increased while stirring to 135 ° C. while passing nitrogen gas. Then, a mixture of 300 parts of cyclohexyl methacrylate, 120 parts of methyl methacrylate, 120 parts of n-butyl acrylate, 60 parts of glycidyl methacrylate, and 60 parts of t-butyl peroxy-2-ethylhexanoate was added dropwise over 3 hours while maintaining the temperature at 135 ° C. Thereafter, aging was performed for 2 hours while maintaining the temperature at 135 ° C. to obtain an almost colorless, transparent and slightly viscous acrylic resin solution (A4) having a nonvolatile content of 60%. The epoxy equivalent was 14,20 on a solids basis.

A5: An acrylic resin for comparative example (A5) was produced as follows. 660 parts of xylene was charged into the flask, and the temperature was raised while stirring to 130 ° C. while passing nitrogen gas. Next, a mixture of 600 parts of methyl methacrylate, 100 parts of methoxyethyl acrylate, 300 parts of n-butyl acrylate, and 40 parts of t-butyl peroxy-2-ethylhexanoate was added dropwise over 3 hours while maintaining the temperature at 130 ° C. Thereafter, the mixture was aged for 2 hours while maintaining the temperature at 130 ° C. to obtain an almost colorless, transparent and slightly sticky acrylic resin solution (A5) having a nonvolatile content of 60%.

B1: “Epicoat 828EL”: Bisphenol A type epoxy resin manufactured by Yuka Shell Co., Ltd., epoxy equivalent 187 B2: “ST-3000”: Product name, hydrogenated bisphenol type epoxy resin epoxy equivalent 230 manufactured by Toto Kasei Co., Ltd. B3: "ST-5080": manufactured by Toto Kasei Co., trade name, bisphenol type epoxy resin / hydrogenated bisphenol type epoxy resin, molecular weight 1200 C1: "KBM-603": manufactured by Shin-Etsu Silicone Co., Ltd., N-β
(Aminoethyl) γ-aminopropyltrimethoxysilane C2: “KBE-903”: manufactured by Shin-Etsu Silicone Co., Ltd., γ-aminopropyltriethoxysilane C3: “Sunmide J-230N”: manufactured by Sanwa Chemical Industry Co., Ltd.
Polyoxypropylene triamine D: "Tinuvin 1130": a benzotriazole-based ultraviolet absorber manufactured by Ciba-Geigy E: "Sanol LS-292": a hindered amine-based ultraviolet stabilizer manufactured by Ciba-Geigy

[0036]

[Table 1]

Test Method Dryness Each coating composition obtained in the composition shown in Table 1 was spray-coated on a steel plate degreased with acetone so that the dry film thickness was about 70 μm, and then dried at room temperature. Curing, JIS
The evaluation was made based on the time required for semi-curing drying specified in K5400. Here, the pass level was within 16 hours. Preparation of Test Coated Plate After coating each paint by the method described above, these were dried at normal temperature (20 ° C.) for 2 weeks to prepare a test coated plate, which was evaluated by the following performance test. Corrosion protection After applying a cut of 1 mm width to each coated plate to reach the substrate, a salt spray test was performed for 500 hours according to JIS K5400.9.1, and the state of the coating film was observed. Was evaluated. ：: No abnormality Δ: Slight rusting X: Notable rusting Weather resistance test Each coated plate was subjected to a test for 500 hours using a sunshine carbon arc lamp type testing machine according to JIS K5400 9.8.1. The glossiness of the coating film at that time was evaluated by comparing it with the initial coating surface not subjected to the accelerated weather resistance test. ：: almost no change △: slight decrease ×: marked decrease

[0038]

According to the coating composition for a single coating finish of the present invention, a cured coating film can be easily formed at room temperature.
Since the obtained cured coating film can maintain weather resistance while maintaining excellent corrosion resistance, it is possible to maintain the aesthetic appearance of a steel structure or the like over a long period of time with a single coating.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J038 CG141 CG142 CH031 CH032 CH041 CH042 CH071 CH072 CH121 CH122 CH171 CH172 CH191 CH192 DB031 DB032 DB041 DB042 DB061 DB062 DB221 DB222 DB361 DB362 DL082 DL101 DL102 GA07 JB18 JB13 J33 NA01 NA03 NA27 PB05 PB06 PB07

Claims (5)

[Claims] 1. A coating composition comprising an acrylic resin (A), an epoxy resin (B) having at least two epoxy groups, and an amine curing agent (C) containing aminosilane.
The acrylic resin (A) contains a cycloalkyl group-containing unsaturated monomer (a) as a copolymer component, and the mixing ratio of the acrylic resin (A) and the epoxy resin (B) is such that (A) is 30 to 70% by weight and (B) is 30 to 70% by weight based on the total of
Anti-corrosion paint composition for multi-coat finish. 2. The anticorrosion paint composition for a one-coat finish according to claim 1, wherein the acrylic resin (A) contains an epoxy group-containing unsaturated monomer (b) as a copolymer component. 3. The method according to claim 1, wherein the acrylic resin (A) contains a UV-absorbing unsaturated monomer (c) and / or a UV-stable unsaturated monomer (d) as a copolymer component. Anticorrosive paint composition for one-time paint finish. 4. The anticorrosion coating composition for a single-coat finish according to claim 1, wherein the weight average molecular weight of the epoxy resin (B) is from 200 to 3,000. 5. An anticorrosion coating composition for a single-coat finish, further comprising an ultraviolet absorber (D) and / or an ultraviolet stabilizer (E) to the coating composition according to any one of claims 1 to 4.