JP2012246344A - Aqueous coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous coating composition excellent in weatherability and wear resistance, and capable of forming a coating film having a sufficient elongation.SOLUTION: The aqueous coating composition contains a polyurethane (A), a weatherability-imparting agent (B) composed of an organic ultraviolet absorbent (b1) and/or a metal oxide particle (b2), a polycarbodiimide (C) and water (D). The (b1) is at least one selected from benzotriazole-based, triazine-based, benzophenone-based, benzoate-based, and hydroxyphenyltriazine-based ultraviolet absorbents. The (b2) is at least one selected from zinc antimonate, titanium oxide, zinc oxide and tin oxide. The content of the (A) in 100 mass% of the total of the (A) and the (B) is 70 to 97 mass%, and the content of the (B) therein is 3 to 30 mass%. The content of (C) in 100 pts.mass of the (A) and the (B) is 1 to 30 pts.mass.

Description

  The present invention relates to a water-based coating composition suitably used for forming a protective coating film on a substrate surface.

  Conventionally, various types of molded products such as automobile interior parts, daily necessities, and optical devices have the surface of a substrate such as a metal substrate or plastic substrate for the purpose of preventing deterioration due to the surrounding environment such as sunlight or physical impact. In general, a protective coating film is formed. Accordingly, the protective coating film is required to have excellent weather resistance and wear resistance.

  Examples of the coating material for forming a protective coating film on a substrate include a thermosetting resin composition (Patent Document 1) containing a polyol, a polyisocyanate and an organic solvent, an ionizing radiation curable compound having a specific functional group, and an organic material. Organic solvent-based paints such as a coating solution containing a solvent (Patent Document 2) are known.

JP 2010-229275 A JP 2010-185000 A

By the way, as a shaping | molding method of a molded article, the method shown below is mentioned, for example.
(1) A composite having a protective coating film formed on a substrate is molded by vacuum molding or the like so as to have a desired shape, and this is placed in a mold, and a resin is injected into the mold. To integrate the composite and resin.
(2) A composite having a protective coating film formed on a substrate is placed in a mold, and after preforming as necessary, a resin is injected into the mold to mold the composite, A method of integrating the composite and the resin.

  In the case of such a molding method, in the method (1), in the process of molding the composite into a desired shape, in the method (2), the composite is along the inner surface of the mold at the time of preforming or resin injection. In the process of being stretched and closely adhered, the substrate is stretched so as to follow the mold shape. Therefore, the protective coating film is also required to have extensibility that can follow the deformation of the substrate.

  However, the protective coatings formed from the paints described in Patent Documents 1 and 2 have insufficient elongation, and have been unable to follow the deformation of the base material and are liable to crack. In particular, cracks are likely to occur when molding into a complicated shape, and in particular, it is prominent at the edge portion and curl portion.

In addition, as described in Patent Documents 1 and 2, in organic solvent-based paints, the organic solvent may volatilize when applied on a substrate, and the coating film has a uniform film thickness compared to water-based paints. It was difficult to form.
Furthermore, organic solvent-based paints have low environmental compatibility, and water-based paints with reduced organic solvent content are desired.

  This invention is made | formed in view of the said situation, and it aims at provision of the water-based coating composition which can form the coating film which is excellent in a weather resistance and abrasion resistance, and has sufficient elongation.

  As a result of intensive studies, the present inventors have found that a water-based coating composition is used in combination with a polyurethane water dispersion, a specific weather resistance imparting agent, and a carbodiimide, and also has weather resistance and abrasion resistance. The present inventors have found that an aqueous coating composition capable of forming a coating film that is excellent and has sufficient elongation properties can be provided, and the present invention has been completed.

That is, the water-based coating composition of the present invention comprises a polyurethane (A), a weather resistance imparting agent (B) comprising an organic ultraviolet absorber (b1) and / or metal oxide particles (b2), and a polycarbodiimide (C). And water (D), wherein the organic ultraviolet absorber (b1) is a benzotriazole ultraviolet absorber, a triazine ultraviolet absorber, a benzophenone ultraviolet absorber, or a benzoate ultraviolet absorber. 1 or more selected from the group consisting of an agent and a hydroxyphenyltriazine-based ultraviolet absorber, and the metal oxide particles (b2) are selected from the group consisting of zinc antimonate, titanium oxide, zinc oxide and tin oxide. The total content of the polyurethane (A) and the weather resistance imparting agent (B) is 100% by mass, and the content of the polyurethane (A) is 70%. 97 mass%, the content of weather resistance imparting agent (B) is 3 to 30 mass%, and the total content of polyurethane (A) and weather resistance imparting agent (B) is 100 mass parts, Content of polycarbodiimide (C) is 1-30 mass parts, It is characterized by the above-mentioned.
The polyurethane (A) is preferably at least one selected from the group consisting of polyether polyurethane, polycarbonate polyurethane, and polyester polyurethane.

  According to the water-based coating composition of the present invention, a coating film having excellent weather resistance and abrasion resistance and sufficient elongation can be formed.

Hereinafter, the present invention will be described in detail.
The water-based coating composition of the present invention comprises a polyurethane (A), a weather resistance imparting agent (B) comprising an organic ultraviolet absorber (b1) and / or metal oxide particles (b2), a polycarbodiimide (C), Water (D).

<Polyurethane (A)>
The polyurethane (A) (hereinafter abbreviated as “component (A)”) plays a role of imparting stretchability and adhesion to the base material to the coating film.
Polyurethane is obtained by reacting a polyol and a polyisocyanate compound. Among them, in terms of being easily dispersed in water, a polyether polyurethane, which is a reaction product of a polyether polyol and a polyisocyanate compound, a polycarbonate polyurethane, a reaction product of a polycarbonate polyol and a polyisocyanate compound, a polyester polyol and a polyisocyanate. Polyester polyurethane, which is a reaction product with the compound, is preferred.

Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.
Examples of the polycarbonate polyol include diol (ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neo And a polycarbonate diol obtained by reacting carbonate (dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, etc.).
Examples of polyester polyols include dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, etc.) and polyhydric alcohols (ethylene glycol, propylene glycol, tetramethylene glycol, 1, 4). -Butanediol, 1,6-hexanediol, neopentyl glycol, trimethylolpropane, pentaerythritol and the like).

  Examples of the polyisocyanate compound include hexamethylene diisocyanate, tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate trimer, hydrogenated xylylene diisocyanate, Examples thereof include hydrogenated diphenylmethane diisocyanate.

(A) component can be used in the state disperse | distributed to water, when manufacturing a water-system coating composition, The aqueous dispersion of a polyurethane is available as a commercial item.
Examples of the water dispersion of polyether polyurethane include “Hydran HW-174” manufactured by DIC Corporation.
Examples of the aqueous dispersion of polycarbonate polyurethane include “Rezamin 6335” manufactured by Dainichi Seika Kogyo Co., Ltd.
Examples of the aqueous dispersion of polyester polyurethane include “Superflex 210” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
(A) A component may be used individually by 1 type and may use 2 or more types together.

  (A) Content of a component is 70-97 mass% in total 100 mass% of content (solid content conversion) of (A) component and the weather resistance provision agent (B) mentioned later in conversion of solid content, 80-95 mass% is preferable. If content of (A) component is more than the said lower limit, the elongation property of a coating film and the adhesiveness with respect to a base material (especially plastic base materials, such as polyester) will improve. On the other hand, if content of (A) component is below the said upper limit, the weather resistance of a coating film will improve.

<Weather resistance imparting agent (B)>
The weather resistance imparting agent (B) (hereinafter abbreviated as “component (B)”) is composed of an organic ultraviolet absorber (b1) and / or metal oxide particles (b2), and imparts weather resistance to the coating film. Play a role.
The organic ultraviolet absorber (b1) is one or more selected from the group consisting of benzotriazole ultraviolet absorbers, triazine ultraviolet absorbers, benzophenone ultraviolet absorbers, benzoate ultraviolet absorbers, and hydroxyphenyltriazine ultraviolet absorbers. It is.

A commercial item can be used as an organic ultraviolet absorber (b1).
Examples of the benzotriazole ultraviolet absorber include “TINUVIN P”, “TINUVIN 234”, “TINUVIN 326”, “TINUVIN 328”, “TINUVIN 329”, “TINUVIN 384”, and “TINUVIN 213” manufactured by BASF Japan Ltd. "TINUVIN 571", "TINUVIN PS", "TINUVIN 99-2", "TINUVIN 109", "TINUVIN 384-2", "TINUVIN 900", "TINUVIN 928", "TINUVIN 1130"; manufactured by Sipro Kasei Co., Ltd. “Seesorb 701”, “Seesorb 703”, “Seesorb 704”, “Seesorb 706”, “Seesorb 707”, “Seesorb 709”, and the like.
Examples of the triazine ultraviolet absorber include “TINUVIN 1577 FF” manufactured by BASF Japan Ltd.
Examples of the benzophenone-based ultraviolet absorber include “CHIMASORB 81” manufactured by BASF Japan Ltd .; “Seasorb 100”, “Seasorb 101”, “Seasorb 101S”, “Seasorb 102”, and “Seasorb 103” manufactured by Sipro Kasei Co., Ltd. , “Seesorb 105”, “Seesorb 106”, “Seesorb 107”, and the like.
Examples of the benzoate UV absorber include “TINUVIN 120” manufactured by BASF Japan Ltd.
Examples of the hydroxyphenyl triazine (HPT) ultraviolet absorber include “TINUVIN 400DW”, “TINUVIN 405”, “TINUVIN 460”, “TINUVIN 477”, and “TINUVIN 479” manufactured by BASF Japan Ltd.

Among these, as the organic ultraviolet absorber (b1), a benzotriazole-based ultraviolet absorber and a hydroxyphenyltriazine-based ultraviolet absorber are preferable because the absorption band for preventing material deterioration is wide.
An organic ultraviolet absorber (b1) may be used individually by 1 type, and may use 2 or more types together.

On the other hand, the metal oxide particles (b2) are at least one selected from the group consisting of zinc antimonate, titanium oxide, zinc oxide, and tin oxide.
Among these, zinc antimonate is preferable as the metal oxide particles (b2) from the viewpoint of excellent heat reflectivity.
A metal oxide particle (b2) may be used individually by 1 type, and may use 2 or more types together.

Further, the average particle diameter of the metal oxide is not particularly limited, but when the content is the same, the surface area of the entire metal oxide increases as the particle diameter decreases, so that the weather resistance of the coating film is easily improved. Accordingly, the average particle size is preferably 5 to 30 nm.
The particle diameter is a value measured by a scanning electron microscope (SEM).

As the component (B), the organic ultraviolet absorber (b1) or the metal oxide particles (b2) may be used, or the organic ultraviolet absorber (b1) and the metal oxide particles (b2) may be used in combination. .
Moreover, (B) component can be used in the state disperse | distributed to water, when manufacturing a water-system coating composition.

  (B) Content of a component is 3-30 mass% in total 100 mass% of content (solid content conversion) of (A) component and (B) component in conversion of solid content, and 5-20 mass%. Is preferred. If content of (B) component is more than the said lower limit, the weather resistance of a coating film will improve. However, when the content of the component (B) becomes excessive, the component (B) bleeds out on the surface of the coating film, and choking tends to occur. When choking occurs, the weather resistance of the coating film tends to decrease. Therefore, from the viewpoint of maintaining the weather resistance of the coating film, the upper limit of the content of the component (B) is 30% by mass or less.

<Polycarbodiimide (C)>
The polycarbodiimide (C) (hereinafter abbreviated as “component (C)”) plays a role of increasing the crosslinking density of the coating film and imparting abrasion resistance to the coating film.
(C) Although it will not restrict | limit especially if it is a polymer which has a carbodiimide group (-N = C = N-) as a component, A water-soluble polymer or an emulsion polymer is preferable.
Commercially available products can be used as such polymers. For example, “Carbodilite E-01”, “Carbodilite E-02”, “Carbodilite E-04”, “Carbodilite SV-02”, “Nisshinbo Chemical Co., Ltd.”, “ “Carbodilite V-02”, “Carbodilite V-04” and the like are preferable. Among them, an emulsion polymer is preferable from the viewpoint of the temporal stability of the water-based coating composition, and “Carbodilite E-02” is particularly preferable.

  (C) Content of a component is 1-30 mass parts with respect to a total of 100 mass parts of content (solid content conversion) of (A) component and (B) component in conversion of solid content, and 10-20 Part by mass is preferred. If content of (C) component is more than the said lower limit, the abrasion resistance of a coating film will improve. On the other hand, if content of (C) component is below the said upper limit, it can suppress that reaction with (A) component advances excessively. Therefore, since the crosslinking density of the coating film does not become too high and the coating film can be prevented from shrinking, adhesion to a substrate (particularly a plastic substrate such as polyester) can be maintained well.

<Water (D)>
It does not specifically limit as water (D) (henceforth "(D) component"), Ion exchange water, distilled water, tap water, etc. are mentioned. Moreover, when manufacturing the water-based coating composition, when using the state in which the components (A) to (C) are dispersed or dissolved in water, the water dispersion or water derived from an aqueous solution may be used as the component (D). Good.
The content of the component (D) is determined in consideration of the content of the components (A) to (C), the concentration of the entire aqueous coating composition, and the like.

<Other ingredients>
In addition to the components (A) to (D), the water-based coating composition of the present invention includes pigments, fillers, plasticizers, surface conditioners, dispersants, coating surface preparation agents, surfactants, Optional components such as a light stabilizer and an antioxidant may be included.
Content of these arbitrary components is suitably adjusted in the range which does not impair the effect of this invention.

Moreover, the water-based coating composition of this invention may contain the organic solvent as needed. Examples of the organic solvent include hydrocarbon solvents such as toluene, xylene, solvent naphtha, methylcyclohexane and ethylcyclohexane; ester solvents such as ethyl acetate, butyl acetate and ethylene glycol monomethyl ether, acetone, methyl ethyl ketone, methyl isobutyl ketone, Examples thereof include ketone solvents such as diisobutyl ketone. An organic solvent may be used individually by 1 type, and may use 2 or more types together.
The content of the organic solvent is appropriately adjusted within a range in which the effects of the present invention are not impaired, but is preferably in the range of 40% by mass or less in 100% by mass of the aqueous coating composition.

<Manufacture of water-based paint composition>
The water-based coating composition of the present invention can be obtained by mixing the components (A) to (D) with an optional component or an organic solvent as necessary.
In addition, as the components (A) to (C), when using an aqueous dispersion or aqueous solution in which these are dispersed or dissolved in water, the components (A) to (C) are mixed with an optional component or an organic solvent as necessary. Then, a water-based coating composition may be used, or the component (D) may be further added and diluted to adjust the solid content concentration of the water-based coating composition.

Since the water-based coating composition of the present invention described above contains specific amounts of the above-described components (A), (B), and (C), the coating composition has excellent weather resistance and abrasion resistance and has sufficient elongation. A film can be formed.
Moreover, since the component (D) is less likely to volatilize when applied to the substrate, the water-based coating composition of the present invention can easily form a coating film having a uniform film thickness as compared with organic solvent-based coatings. In addition, it is more environmentally friendly than organic solvent-based paints.

<Application>
Since the coating film formed from the water-based coating composition of the present invention is excellent in weather resistance and abrasion resistance, it is suitable as a protective coating film for protecting the substrate surface.
Examples of the substrate include a metal substrate and a plastic substrate.

  Examples of the material of the metal substrate include aluminum, iron, nickel, chromium, titanium, copper, silver, zinc, tin, indium, magnesium, oxides thereof, and alloys thereof.

On the other hand, the material of the plastic substrate is, for example, polyester, polyolefin, polycarbonate, acrylonitrile-butadiene-styrene copolymer resin (ABS), acrylic resin, acrylonitrile-styrene copolymer resin, acrylic-styrene copolymer resin, polyvinyl chloride resin. Etc. Among these, polyester is preferable in that it is particularly excellent in adhesion to a coating film formed from the aqueous coating composition of the present invention.
The polyester is not particularly limited as long as it is a polycondensate of dicarboxylic acid and diol, and examples thereof include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. In particular, from the viewpoint of stretchability, PET is preferable, and biaxially stretched PET is more preferable.

The shape of the substrate is not particularly limited, and may be either a film shape or a three-dimensional shape.
Moreover, from the viewpoint of improving the adhesion to the coating film, the substrate surface on which the coating film is formed is preferably subjected to pretreatment such as corona discharge treatment or plasma treatment.
Moreover, metal vapor deposition may be given to the surface of the plastic base material.

  The method for applying the water-based coating composition to the substrate is not particularly limited, and a known method can be employed. Specifically, the spray coating method, the brush coating method, the roller coating method, the curtain coating method, the flow coating method, the dip coating method, etc. are performed on the substrate so that the film thickness after drying becomes about 15 to 25 μm. Apply. Subsequently, the composite body in which the coating film (protective coating film) which consists of a water-system coating composition of this invention was formed on the base material by drying at 80-150 degreeC is obtained.

  A composite having a protective coating film formed on a substrate can be used as it is for various applications as a molded product. However, when the substrate is in the form of a film, the composite is used for, for example, insert molding to have a desired shape. You may shape | mold to the molded article of.

When the composite is used for insert molding, the molded product is obtained by, for example, the following method.
(1) A composite having a protective coating film formed on a substrate is molded by vacuum molding or the like so as to have a desired shape, and this is placed in a mold, and a resin is injected into the mold. To integrate the composite and resin.
(2) A composite having a protective coating film formed on a substrate is placed in a mold, and after preforming as necessary, a resin is injected into the mold to mold the composite, A method of integrating the composite and the resin.

  As described above, in the method (1), in the process of forming the composite into a desired shape, in the method (2), the composite is stretched along the inner surface of the mold at the time of preforming or resin injection. In the process of adhering, the substrate is stretched so as to follow the mold shape. Therefore, a protective coating film formed from a conventional paint cannot easily follow the deformation of the base material and is liable to crack.

However, the water-based coating composition of the present invention can form a coating film having sufficient elongation. Therefore, since the coating film (protective coating film) formed from the water-based coating composition of the present invention can easily follow the deformation of the substrate, the protective coating film is cracked when the composite is formed into a desired shape. Is unlikely to occur.
Furthermore, when a base material is a film form, the composite_body | complex with which the coating film was formed on the base material is normally stored and conveyed in the state wound up by the roll etc. Since the coating film formed from the water-based coating composition of the present invention has sufficient elongation, the composite can be wound smoothly.

  Examples of the use of the molded article include various molded articles such as automobile interior parts (switch parts and the like), household goods (various containers and the like), and optical devices (display diffusion films and the like).

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these. In the examples, “part” indicates “part by mass”, and “%” indicates “% by mass”.
The raw materials used in the examples and comparative examples are shown below.

[Raw materials]
As the component (A), the following compounds were used.
A-1: A water dispersion of a polyether-based polyurethane (manufactured by DIC Corporation, “Hydran HW-174”), solid content: 35%
A-2: Polycarbonate-based polyurethane aqueous dispersion (manufactured by Dainichi Seika Kogyo Co., Ltd., “Resamine 6335”), solid content 35%
A-3: A water dispersion of polyester polyurethane (Daiichi Kogyo Seiyaku Co., Ltd., “Superflex 210”), solid content 35%

As the component (B), the following compounds were used.
B1-1: Hydroxyphenyltriazine-based UV absorber (manufactured by BASF Japan Ltd., “TINUVIN 400DW”), solid content 20%
B1-2: Benzotriazole ultraviolet absorber (manufactured by BASF Japan, “TINUVIN 1130”), solid content 100%
B2-1: Zinc antimonate (ZnSb ₂ O ₆ ) (manufactured by Nissan Chemical Industries, Ltd., “CELNAX 2330HF2”), solid content 30%

As the component (C), the following compounds were used.
C-1: Carbodiimide (Nisshinbo Chemical Co., Ltd., “Carbodilite E-02”), solid content 40%

[Example 1]
<Manufacture of water-based paint composition>
257 parts (90 parts in terms of solid content) as component (A) and 50 parts (10 parts in terms of solid content) of b1-1 as component (B) were stirred and mixed to obtain a uniform component. As a component (C), 27.5 parts (11 parts in terms of solid content) of c-1 was added to the resulting mixture to obtain an aqueous coating composition.
Table 1 shows the composition of each component. In addition, the value shown in Table 1 is the value which converted each component into solid content.

<Evaluation>
(Preparation of test piece)
A biaxially stretched low density polyethylene terephthalate (PET) film (length 30 cm, width 50 cm) is coated with a water-based coating composition with a bar coater or applicator so that the film thickness after drying is 25 μm, 140 ° C. × 3 minutes A film was formed by drying under the above conditions, and this was used as a test piece.
Each test piece was evaluated as follows to evaluate the stretchability, weather resistance, abrasion resistance, and adhesion to the substrate of the coating film. The results are shown in Table 1.

(Evaluation of elongation)
The test piece was put into a hot-air circulating drying furnace set at 150 ° C. for 10 seconds and then taken out. At the same time, the test piece was pulled with both hands until just before the test piece was cut. The length of the test piece in the tensile direction was measured, the elongation (elongation) was determined by comparison with the length before the test piece was pulled, and the stretchability of the coating film was evaluated according to the following evaluation criteria.
○: Elongation is 200 mm or more.
X: Elongation is less than 200 mm.

(Evaluation of weather resistance)
Using a xenon lamp, the coating film of the test piece was irradiated with light of 180 W / cm ² for 3000 hours from a position 290 mm away. About the test piece after light irradiation, the color difference ((DELTA) E) of the coating film was measured and the weather resistance of the coating film was evaluated on the following evaluation criteria.
○: ΔE ≦ 2
×: 2 <ΔE

(Evaluation of wear resistance)
The test piece was placed in a traverse type testing machine, and the surface of the coating film was rubbed back and forth 5000 times with a load of 1 N using cotton canvas as an abrasion material. The rubbed portion was visually observed, and the abrasion resistance of the coating film was evaluated according to the following evaluation criteria.
○: No exposure of the substrate (PET film).
X: The substrate (PET film) is exposed.

(Evaluation of adhesion)
A test piece was cut into a 10 mm grid pattern with a width of 1 mm and a cellophane tape was applied to and peeled off a cellophane tape on the grid pattern of the test piece. Adhesion was evaluated.
○: When the coating film does not adhere to the tape at all.
Δ: The corner of the grid is slightly missing.
X: When even one grid is attached to the tape and peeled off.

[Examples 2 to 9, Comparative Examples 1 to 5]
Except having changed the kind and compounding quantity of each component into the value shown in Table 1, 2, the aqueous coating material composition was manufactured similarly to Example 1, and each evaluation was performed. The results are shown in Tables 1 and 2.
In addition, the value shown to Table 1, 2 is the value which converted each component into solid content.

[Comparative Example 6]
40 parts of a polycaprolactone resin (Daicel Chemical Industries, Ltd., “Placcel 305”), 30 parts of a polyol resin (Sanyo Chemical Industries, Ltd., “Sannick PP-1000”), and a polyol resin (Sanyo Chemical Industries) Co., Ltd., “Sannic GP-400”) and 25 parts of ethyl acetate were mixed by stirring and homogenized to obtain a thermosetting organic solvent coating composition.
A test piece was prepared in the same manner as in Example 1 except that 10 parts of a crosslinking agent (“E402-80T” manufactured by Asahi Kasei Chemicals Corporation) was added to the obtained coating composition, and evaluation of extensibility was performed. Went. The results are shown in Table 2.

[Comparative Example 7]
5 parts of a polyfunctional acrylate resin (pentaerythritol triacrylate, “NK Ester-A-TMM-3LM-N” manufactured by Shin-Nakamura Chemical Co., Ltd.) and urethane acrylate resin (manufactured by DIC Corporation, “Unidic 17” -849 "), 40 parts, 30 parts of a polyfunctional acrylate resin (Trimethylolpropane triacrylate manufactured by Sartomer," Sartomer SR351S "), and a monofunctional acrylate resin (tetrahydrofurfuryl manufactured by Osaka Organic Chemical Industry Co., Ltd.) 15 parts of acrylate, “THF-A”) and 10 parts of a photopolymerization initiator (“Irgacure 651” manufactured by BASF Japan Ltd.) are mixed by stirring and homogenized to obtain an active energy ray-curable coating composition. It was.
A coating composition obtained so that the film thickness after drying is 25 μm is applied to a PET film with a bar coater, and ultraviolet rays of 500 mJ (measured by UVR-N1 manufactured by Nihon Battery Co., Ltd.) are applied with a high pressure mercury lamp. Irradiated for minutes to form a coating film, which was used as a test piece.
About the obtained test piece, the test piece was produced similarly to Example 1, and the extensibility was evaluated. The results are shown in Table 2.

  As is clear from Table 1, the water-based coating compositions obtained in each example were able to form a coating film excellent in elongation, weather resistance, and abrasion resistance. Moreover, these water-based coating compositions had satisfactory adhesion to the substrate of the coating film, and were sufficiently satisfactory as coating materials.

On the other hand, as apparent from Table 2, the coating film formed from the aqueous coating composition of Comparative Example 1 containing no component (A) was inferior in elongation. Moreover, since the water-based coating composition of Comparative Example 1 has few resin components, it is difficult to form a coating film even when applied on a substrate, and it is not only inferior in wear resistance but also inadequate adhesion to the substrate. Yes, it was not satisfactory as a paint.
The coating film formed from the aqueous coating composition of Comparative Example 2 containing no component (B) was inferior in weather resistance.
The coating film formed from the water-based coating composition of Comparative Example 3 having a low content of the component (A) in terms of solid content of 60 parts and a high content of the component (B) in terms of solid content of 40 parts. Inferior in elongation and weather resistance. Moreover, the water-based coating composition of Comparative Example 3 was not satisfactory as a coating because the adhesion of the coating film to the substrate was insufficient.
The coating film formed from the water-based coating composition of Comparative Example 4 containing no component (C) was inferior in wear resistance.
The water-based coating composition of Comparative Example 5 having a high content of component (C) in terms of solid content of 40 parts had insufficient adhesion to the substrate of the coating film and was not satisfactory as a coating.
The coating films formed from the coating compositions of Comparative Examples 6 and 7 were inferior in elongation.

Claims (2)

Water-based paint containing polyurethane (A), weather resistance-imparting agent (B) comprising organic ultraviolet absorber (b1) and / or metal oxide particles (b2), polycarbodiimide (C), and water (D) A composition comprising:
The organic ultraviolet absorber (b1) is one selected from the group consisting of benzotriazole ultraviolet absorbers, triazine ultraviolet absorbers, benzophenone ultraviolet absorbers, benzoate ultraviolet absorbers, and hydroxyphenyltriazine ultraviolet absorbers. That's it,
The metal oxide particles (b2) are at least one selected from the group consisting of zinc antimonate, titanium oxide, zinc oxide, tin oxide,
In a total of 100% by mass of the contents of the polyurethane (A) and the weather resistance imparting agent (B), the content of the polyurethane (A) is 70 to 97% by mass, and the content of the weather resistance imparting agent (B) is 3 to 3. 30% by mass,
And the content of the said polycarbodiimide (C) is 1-30 mass parts with respect to a total of 100 mass parts of content of a polyurethane (A) and a weather resistance imparting agent (B), The water-based coating material characterized by the above-mentioned. Composition.   The water-based paint composition according to claim 1, wherein the polyurethane (A) is at least one selected from the group consisting of polyether-based polyurethane, polycarbonate-based polyurethane, and polyester-based polyurethane.