JPH05171100A - Coating composition, its production, and formation of coating film - Google Patents

Abstract

PURPOSE:To provide a coating composition which can form a coating film having an easily controllable degree of mattedness, being free from surface defects such as nonuniform gloss and gas pinholes, undergoing small change in gloss in continuous coating and capable of retaining stable mattedness. CONSTITUTION:A water-base coating composition comprising an acrylic copolymer resin (I) containing hydrolyzable alkoxysilane, an acrylic copolymer resin (II) containing hydrolyzable alkoxysilane and a crosslinking agent (III) (provided that at least one of components I and II contains acidic or hydroxyl groups) and being neutralized with a basic substance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition, a method for producing the same, and a method for forming a coating film, more specifically, an acrylic resin containing a hydrolyzable alkoxysilane group and an acrylic resin containing no hydrolyzable alkoxysilane group. The present invention relates to a coating composition in which a resin is used in common, a glossiness can be easily controlled, and a stable matte state can be obtained, a method for producing the same, and a method for forming a matte coating film by coating the paint.

[0002]

2. Description of the Related Art As a method for obtaining a matte coating film by electrodeposition coating, a method of incorporating an inorganic pigment such as silica fine powder (see, for example, Japanese Patent Laid-Open Publication No. Sho.
56-75596) and a method of incorporating fine powder such as polyethylene or polypropylene (for example, JP-A-60-135466).
No.), a method of post-treating an electrodeposition coating film with an acidic treatment liquid (for example, JP-A-52-137444). However, in these methods, there is a problem that not only the durability of the matting effect is poor but also uneven gloss occurs,
Further, the method of performing the post-treatment has a problem that the number of steps is increased, and gloss unevenness is likely to occur at the time of withdrawing from the treatment solution or washing with water. In addition, there are drawbacks such as side effects in terms of coating film performance.

As a method for matting an electrodeposition coating composition which overcomes the above-mentioned drawbacks, a method of introducing an alkoxysilane group into a side chain to form an insoluble intragranular gel structure in a copolymer resin is known.
It is described in JP-B-62-24519. However, this method has a problem that the gloss varies depending on the coating conditions, and it is not sufficient to control the degree of matte, and it is sufficient for the market needs from complete matte to slightly matte level. I can not respond. Also, depending on the use of the formed matte coating, it is necessary to have a wide range of flexibility of coatings, from hard to soft.
The above method was insufficient in controlling the flexibility.
In addition, since the coating film fluidity during baking is not sufficient after electrodeposition, there is a problem that coating film defects such as gas pinholes during electrodeposition tend to remain.

Further, an aqueous dispersion (1) of a copolymer resin having an alkoxysilane group in its side chain, and a copolymer resin having no alkoxysilane group and a melamine resin having no compatibility with these copolymer resins. JP-A-2-255871 describes a coating composition prepared by mixing an aqueous dispersion (2) in which is dispersed. This method has the advantage that the use of a specific melamine resin makes it matte by a method other than electrodeposition coating. However, since the dispersion particles containing an alkoxysilane group and the dispersion particles not containing an alkoxysilane group are separately present in the aqueous dispersion, in the case of electrodeposition coating,
There is a difference in electrophoretic property among the dispersed particles. As a result, the problem that the gloss varies depending on the coating conditions and the like still remains.

Therefore, the object of the present invention is to solve the above-mentioned problems, to easily control the matteness, to form a coating film having a stable matt state with few coating film defects such as gas pinholes. A coating composition, a method for producing the same, and a coating method are provided.

[0006]

As a result of earnest research in view of the above object, the present inventors have found that the acrylic copolymer resin containing a hydrolyzable alkoxysilane group and the acrylic copolymer resin containing no hydrolyzable alkoxysilane group. After homogenizing the mixture with the acrylic copolymer resin, the mixture is dispersed in water to coexist a portion containing an alkoxysilane group and a portion not containing an alkoxysilane group in the same dispersed particles, thereby providing a matte The present invention was completed by discovering that it is possible to obtain a coating composition which is easy to control and has a stable matte state with few coating film defects.

The coating composition of the present invention comprises the following components (I) to (I
II): (I) Acrylic copolymer resin containing hydrolyzable alkoxysilane, (II) Acrylic copolymer resin containing no hydrolyzable alkoxysilane, and (III) Crosslinking agent (provided that component (I) At least one of (2) and (II) contains an acid group and a hydroxyl group), and is an aqueous coating composition, which is neutralized with a basic substance.

The method for producing a coating composition of the present invention comprises the following components (I) to (III): (I) an acrylic copolymer resin containing a hydrolyzable alkoxysilane, and (II) a hydrolyzable alkoxysilane. Acrylic copolymer resin not contained, and (III) cross-linking agent (provided that at least one of components (I) and (II) contains an acid group and a hydroxyl group.) Were mixed and neutralized with a basic substance. After that, water is added.

The method for forming a matte coating film of the present invention comprises the following components
(I) to (III): (I) Acrylic copolymer resin containing hydrolyzable alkoxysilane, (II) Acrylic copolymer resin containing no hydrolyzable alkoxysilane, and (III) Crosslinking agent (however , At least one of the components (I) and (II) contains an acid group and a hydroxyl group.), Neutralize with a basic substance, and then add water to obtain an aqueous dispersion. Is characterized by.

The present invention is described in detail below. (I) Acrylic containing a hydrolyzable alkoxysilane group
Acrylic copolymer resin containing system copolymer resin hydrolyzable alkoxysilane groups as a monomer component, as essential components a polymerizable unsaturated monomer containing (a) a hydrolyzable alkoxysilane group, In addition, (b) a polymerizable unsaturated monomer containing a carboxyl group, (c) a polymerizable unsaturated monomer containing a hydroxyl group, (d) one of other polymerizable unsaturated monomers, or It is obtained by appropriately copolymerizing two or more kinds.

The component (a) in the component (a) copolymer resin (I) is present in the dispersed particles by a condensation reaction after hydrolysis of the alkoxysilane group when the copolymer resin is dispersed in water. It is a component for preparing a partially crosslinked gel component. As such a component (a), divinyldimethoxysilane, divinyl-β-dimethoxyethoxysilane, vinyltrimethoxysilane, vinyltripropoxysilane, vinyltriethoxysilane,
Vinyltributoxysilane, vinyltripentoxysilane, vinyltri-β-methoxyethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, trimethoxyallylsilane, triethoxyallylsilane, (meth)
Examples thereof include unsaturated dialkoxysilane compounds or unsaturated trialkoxysilane compounds such as acryloylmethyltrimethoxysilane, (meth) acryloylethyltrimethoxysilane, (meth) acryloylpropyltrimethoxysilane and the like.

The amount of the component (a) used is determined depending on the desired matting degree and the compounding ratio of the copolymer resin (I) and the copolymer resin (II). From the perspective of the stability of
The content of the copolymer resin (I) is preferably 1 to 30% by weight based on 100% by weight.

Component (b) Component (b) mainly imparts water-dilutability, electrophoretic property, catalytic action during curing, etc. to the copolymer resin. As such a component (b), it is preferable to use acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid or the like alone or in combination.

The content of the component (b) is such that it is water-dilutable, matte,
In terms of paint stability, etc., copolymer resin (I) and copolymer resin (I
It is preferable to determine the acid value of the whole mixture of I) to be 20 to 150, especially 30 to 100.

Component (c) The component (c) mainly imparts reactivity with the (III) crosslinking agent described below. As such a component (c), 2-
It is preferable to use hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, etc. alone or in combination.

The content of the component (c) is 20 to 150, especially 40 to 100, in terms of curability and appearance of the coating film, in the whole mixture of the copolymer resin (I) and the copolymer resin (II). It is preferable to determine that

Component (d) Component (d) is a component that mainly forms the skeleton of the copolymer resin. As such component (d), in addition to alkyl esters of acrylic acid and methacrylic acid, ordinary polymerizable unsaturated monomers can be used. Examples of these are methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n.
-Butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, t
-Butyl acrylate, t-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, etc., as well as styrene, methylstyrene, vinyltoluene, vinyl acetate. , Acrylonitrile,
Examples thereof include acrylamide, methacrylamide, methylol acrylamide, methylol methacrylamide, and n-butoxymethyl acrylamide.

(II) Containing hydrolyzable alkoxysilane group
Not included Acrylic copolymer resin Acrylic copolymer resin containing no hydrolyzable alkoxysilane group is the same as the above-mentioned component (b), component (c) and component (d).
It is obtained by appropriately copolymerizing two or more species.

Here, it is necessary that at least one of the copolymer resin (I) and the copolymer resin (II) contains the component (b) and the component (c). For example, the copolymer resin (I) is the component (b)
If the component (c) is not contained, the copolymer resin
(II) must contain component (c). When the copolymer resin (I) contains neither component (b) nor component (c), the copolymer resin (II) contains component (b) and component (c).
Must be included. Both the copolymer resin (I) and the copolymer resin (II) may contain the component (b) and the component (c).

From the viewpoint of the durability and workability of the coating film, the preferred molecular weight of the copolymer resins (I) and (II) is the number average molecular weight.
3,000 to 70,000, especially 10,000 to 50,000. From the viewpoint of hardness and flexibility, the preferred glass transition temperature is -20 to +60.
C., especially 0 to 50.degree.

The copolymer resins (I) and (II) can be obtained by polymerizing the above-mentioned monomers by a known method.
Especially isopropyl alcohol, isobutyl alcohol,
It is preferably obtained by solution polymerization using a hydrophilic solvent such as n-butyl alcohol, ethyl cellosolve or butyl cellosolve.

(III) Crosslinking Agent As the crosslinking agent, an amino resin and / or a blocked isocyanate compound can be used.

The amino resin includes melamine resin, benzoguanamine resin and the like, and preferably melamine resin. As the melamine resin, a mixed alkyl etherified methylol melamine resin is preferable, and a butyl ether group having 30% or more in the ether group is particularly preferable.

As the blocked isocyanate compound,
Blocked with alcohols, phenols, acetylacetone, ethyl acetoacetate, MEK oxime, ε-caprolactam, etc., the dissociation temperature is 100 to 180 ° C, preferably
Tolylene diisocyanate (TDI) from 120 ℃ to 160 ℃
System, diphenylmethane diisocyanate (MDI) system,
An aliphatic or alicyclic polyfunctional isocyanate such as hexamethylene diisocyanate (HDI) type or isophorone diisocyanate (IPDI) type can be used.

In the present invention, the copolymer resin (I), the copolymer resin (II) and the cross-linking agent need to be sufficiently mixed before water dispersion.

The mixing ratio of these components depends on the copolymer resin.
Depends on whether (I) contains component (b) or not. That is, when the copolymer resin (I) contains the component (b), the solid content weight ratio is (I) / (II) = 95/5 to 20/80, particularly 90/10 to 50.
It is preferably / 50. In addition, the copolymer resin (I) is a component
When (b) is not contained, (I) / (II) = 5 / 95-80 / 20,
It is particularly preferably 10/90 to 50/50. The mixing ratio with the cross-linking agent is {(I) + (II)} / (III) = 90 / 10-40 /
It is preferably 60, particularly 80/20 to 50/50.

After sufficiently mixing the components (I) to (III), the carboxyl group contained in the copolymer resin is neutralized with a basic substance such as an organic amine or an inorganic base to impart water dispersibility. To do. Suitable examples of the basic substance include monomethylamine, dimethylamine, dimethylethanolamine, trimethylamine, triethylamine, triethanolamine, diisopropylamine and the like.
The neutralization rate with a basic substance is preferably 20% to 100%, and particularly preferably 40% to 90%, from the viewpoint of water dispersibility and coating stability.

After imparting water dispersibility, the mixture is diluted with water to give an aqueous dispersion. At this time, it is desirable to immediately dilute with water after neutralization. If the mixture is left for a long time after neutralization, gelation of the mixture may occur, which is not preferable.

Further, if desired, in addition to a surfactant, a solvent, a colorant, a conventional additive for paints can be mixed and used.

The obtained aqueous dispersion is diluted with water so as to have a solid content of 3 to 20% by weight, preferably 5 to 15% by weight and used as a matte electrodeposition coating composition. The electrodeposition coating is carried out by immersing the article to be coated in the thus-prepared matte electrodeposition coating composition and energizing so that the article to be coated becomes an anode. Electrodeposition conditions are usually bath temperature 15-35 ℃, coating voltage 80-350V,
And the electrodeposition time is 1 to 5 minutes. After coating, the article to be coated is washed with water if necessary, and then heat-cured at 140 to 200 ° C for 10 to 60 minutes. Thus, an electrodeposition coating film having a desired matte effect is formed. Usually, a dry coating film of 5 to 30 μm is suitable.

The article to be applied to the matte electrodeposition coating method of the present invention is not particularly limited as long as it has conductivity, but when aluminum or aluminum alloy is used as the article to be coated, the gloss is stable, It is possible to obtain a uniform matte coating film without coating film defects. The matte electrodeposition coating composition and coating method of the present invention are particularly suitable for matte coating of aluminum members such as aluminum sashes.

The coating composition of the present invention is suitable for electrodeposition coating, but by changing the combination of components (I), (II) and (III), coating methods other than electrodeposition coating, For example, a good matte coating film can be obtained by spray coating or the like.

[0033]

[Function] In forming a matte electrodeposition coating film containing a hydrolyzable alkoxysilane group, an acrylic copolymer resin containing a hydrolyzable alkoxysilane group and an acrylic copolymer resin containing no hydrolyzable alkoxysilane group are used. After sufficiently mixing with the polymerized resin, neutralized with a basic substance and dispersed in water to easily obtain a coating film having a desired matting degree,
Moreover, the obtained coating film has the advantages that it has few defects such as gas pinholes and that the gloss variation due to electrodeposition coating conditions is small.

Electrodeposition coating is carried out using the above-mentioned electrodeposition coating composition, and the resulting coating film is baked and cured to finally obtain a matte coating film having fine irregularities formed on the surface. The generation mechanism of this fine unevenness is not clear, but due to the influence of the gel component in the dispersed particles due to the condensation reaction of the hydrolyzable alkoxysilane,
It is presumed that this is because the irregularities are formed during the deposition of the electrodeposition coating film, and the irregularities are also formed due to the shrinkage strain during heat curing.

In particular, the coexistence of a gel component portion resulting from the reaction of an alkoxysilane group and a non-gel component portion containing no alkoxysilane group in the same dispersed particles increases the fluidity at the time of heating, and the gas pin It is considered that a good matte state can be obtained by reducing coating film defects such as holes and further increasing the uniformity of shrinkage strain during curing.

It is important that the gel component part and the non-gel component part coexist in the same dispersed particle, and each dispersion is different from the case where the gel component-containing particle and the non-gel component-containing particle are present as separate dispersed particles. Because the electrophoretic properties of the particles are the same,
The composition of the electrodeposition coating film does not change even if the coating conditions are changed or long-term continuous coating, and a stable matte state can be obtained.

[0037]

The present invention will be described in more detail by the following examples.

Production Example I-1 Production of Copolymer Resin Solution (I) In a reaction vessel, 400 parts by weight of isopropyl alcohol, n
220 parts by weight of butyl alcohol were charged and the temperature was raised to 80 ° C. 80 parts by weight of acrylic acid, 200 parts by weight of 2-hydroxyethyl methacrylate, 2 parts of methyl methacrylate
A mixture of 60 parts by weight, styrene 170 parts by weight, n-butyl acrylate 180 parts by weight, ethyl acrylate 80 parts by weight, γ-methacrylooxypropyltrimethoxysilane 30 parts by weight, and azobisisobutyronitrile 7 parts by weight was prepared. It was added dropwise in 4 hours. One hour after completion of the dropping, a mixture of 20 parts by weight of azobisisobutyronitrile and 100 parts by weight of isopropyl alcohol was added dropwise over 3 hours, and after completion of the addition, stirring was continued for another 2 hours to complete the polymerization, and to add water. Copolymer resin solution containing decomposable alkoxysilane groups (I)
Got

Production Examples I-2 to II-5 Production of Copolymer Resin Solutions (I) and (II) In the same manner as in Production Example I-1, the monomer composition was changed as shown in Table 1, Each copolymer resin solution was obtained.

Table 1 Production Example Monomer composition in copolymer resin solution (I) I-1 I-2 I-3 I-4 I-5 γ-methacryloxypropyl trimethoxysilane 30 ── 100 100 150 vinyl Trimethoxysilane ── 40 ── ── ── Acrylic acid 80 70 ── ── ── Methacrylic acid ── ── ── 150 ── 2-hydroxyethyl methacrylate 200 ── 250 ── ── 2-hydroxyethyl Acrylate ── 150 ── ── ── Methyl methacrylate 260 290 260 200 350 n-Butyl acrylate 180 100 180 ── 100 Ethyl acrylate 80 150 210 400 300 n-Butyl methacrylate ── 200 ── ── 100 Styrene 170 ── ── 150 ──

Table 1 (continued) Production Example Monomer composition in copolymer resin solution (II) II-1 II-2 II-3 II-4 II-5 Acrylic acid 80 70 150 ──── Methacrylic acid ─ ─ ─ ─ ─ ─ ─ ─ 180 2-Hydroxyethyl methacrylate 200 ─ ─ ─ ─ 280 ─ ─ 2-hydroxyethyl acrylate ─ ─ 150 ─ ─ ─ 220 Methyl methacrylate 260 290 300 250 200 n-butyl acrylate 180 100 200 ─ ─ 300 Ethyl acrylate 110 150 230 370 100 n-Butyl methacrylate ── 200 ── ── ── Styrene 170 ── 120 100 ──

Example 1 As shown in Table 2 below, 1570 parts by weight of the copolymer resin solution (I-1) obtained in Production Example I-1, the copolymer resin solution obtained in Production Example II-1 (II-1) 170 parts by weight, Cymel 2
670 parts by weight of 35 (mixed alkyl ether type methylol melamine resin: non-volatile content 100%, manufactured by Mitsui Cyanamide Co., Ltd.) were mixed with stirring at room temperature for 1 hour. Then, water was gradually added to disperse it in water to prepare an electrodeposition paint having a resin solid content concentration of 10% by weight.

This electrodeposition coating material was placed in an electrodeposition tank, and an anodized 6063S aluminum plate was immersed in the electrodeposition tank. The aluminum plate was used as an anode at a bath temperature of 22 ° C. and a cured film thickness was
A voltage of 10 μm was applied for 3 minutes to carry out electrodeposition coating. After completion of electrodeposition, each coated plate was washed with wash water containing 3% by weight of isopropyl alcohol and 1% by weight of butyl cellosolve, and cured by heating at 180 ° C. for 30 minutes, and the performance evaluation of each obtained electrodeposition coating film I went. The results are shown in Table 3.

Examples 2 to 7 Electrodeposition paints were prepared in the same manner as in Example 1 except that the type and blending ratio of the copolymer resin solution were changed as shown in Table 2, and the same tests were conducted. The results are shown in Table 3.

Table 2 Examples Compounding ratio 1 2 3 4 5 6 7 (I) Copolymer resin I-1 I-1 I-1 I-2 I-3 I-4 I-5 Compounding amount 1570 1390 1220 1390 780 1040 700 (II) Copolymer resin II-1 II-1 II-1 II-2 II-3 II-4 II-5 Blend amount 170 350 520 350 960 700 1040 (III) Crosslinking agent ^* Blend amount 670 670 670 670 540 540 540 Neutralizer ^** Compounding amount 60 60 60 60 70 60 70 (Note) *: Cymel 235 **: Triethylamine

Comparative Example 1 The copolymer resin solution (II-1) obtained in Production Example I-1 was used without using the copolymer resin solution (II-1) obtained in Production Example II-1.
-1) was used in the same manner as in Example 1 except that 1740 parts by weight was used, and the same test as in Example 1 was performed. The results are shown in Table 3.

Comparative Example 2 Copolymer resin solution (I-1) 1390 obtained in Production Example I-1
By weight, 535 parts by weight of a cross-linking agent (Cymel 235) and 42 parts by weight of triethylamine were stirred and mixed at room temperature for 1 hour, and water was gradually added to disperse the water to obtain a dispersion liquid (I). Similarly, the copolymer resin solution (II-1) obtained in Production Example II-1
350 parts by weight, 135 parts by weight of a crosslinking agent (Cymel 235), and 12 parts by weight of triethylamine were stirred and mixed at room temperature for 1 hour, and water was gradually added to disperse the water to obtain a dispersion liquid (II). Dispersion liquid (I) and dispersion liquid (II)
(II) = 8/2 by weight (solid content basis) were mixed to prepare an electrodeposition coating composition having a resin solid content of 10% by weight, and the same test as in Example 1 was conducted. The results are shown in Table 3.

Table 3 Example coating film characteristics 1 2 3 4 5 Hikarizawa (1) 12 19 29 20 26 Appearance (2) No gloss unevenness No No No No No Gas pinhole No No No No No Hardness (3) 4H 4H 4H 4H 4H 4H Alkali resistance (4) Good Good Good Good Good Good Acid resistance (5) Good Good Good Good Good Adhesion (6) 100/100 100/100 100/100 100/100 100/100 Continuous paintability (7 ) Good Good Good Good Good Good

Table 3 (continued) Example Comparative Example Coating Properties 6 7 1 2 Kosawa (1) 22 30 9 18 Appearance (2) No gloss unevenness No No No Yes Gas pin hole No No Yes Yes No Hardness (3 ) 4H 4H 4H 4H 4H Alkali resistance (4) Good Good Good Good Good Acid resistance (5) Good Good Good Good Good Adhesion (6) 100/100 100/100 100/100 100/100 Continuous paintability (7) Good Good Good Bad

Evaluation method and evaluation criteria

(1) Luminousness due to specular reflection of 60 ° light was measured according to JIS K5400 7.6.

(2) Appearance of coating film The surface of the electrodeposition coating film after baking was visually observed to evaluate the presence or absence of uneven glossiness and the presence or absence of gas pin holes.

(3) Hardness The coating film after baking was gradually cooled to 20 ° C., and then a pencil scratching test was conducted according to JIS K5400 8.4. The hardness of a coating film is expressed by the hardness of a pencil with scratches.

(4) Alkali resistance A 1% aqueous solution of sodium hydroxide was used to carry out a spot test for 24 hours (temperature: 23 ° C.), after which the presence or absence of abnormality on the coating film surface was observed.

(5) Acid resistance A 5% aqueous sulfuric acid solution was used to carry out a spot test for 24 hours at a temperature of 23 ° C., after which abnormalities on the coating film surface were observed.

(6) Adhesiveness A 1 × 10 mm goggles test (according to JIS K5400) was performed. The adhesion to the aluminum substrate is displayed by the number of stitches that do not peel off / 100.

(7) Continuous coating property A predetermined number of sheets were continuously coated, and those having a gloss difference of 3 or less were evaluated as "good", and those having a gloss difference of 5 or more were evaluated as "poor".

As is clear from Table 3, the coating films of Examples 1 to 7 according to the method of the present invention had a good matte appearance, and neither gloss unevenness nor gas pinholes were observed. On the other hand, the coating films prepared by the methods of Comparative Examples 1 and 2 were found to have uneven gloss, gas pinholes, etc. In particular, Comparative Example 2 showed a large variation in the gloss difference in the continuous coating test, and a stable gloss was obtained. There wasn't.

[0059]

As described in detail above, a specific acrylic copolymer resin containing an alkoxysilane group and an acrylic copolymer resin containing no alkoxysilane group are thoroughly mixed and then mixed with a basic substance. By adopting the method of softening and water dispersion, a coating film having a desired mattness can be easily obtained, and the obtained coating film has few coating defects such as uneven gloss and gas pinholes and is continuous. It has the advantage that there is little fluctuation in gloss during painting.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yusuke Misaka 2-1, Chikusaigan, Ichihara-shi, Chiba Toray Co., Ltd. Chiba factory (72) Inventor Yukihiko Nishitani 4-1, 15 Minamishinagawa, Shinagawa-ku, Tokyo Japan Paint Co., Ltd. Tokyo office (72) Inventor Masatoshi Ono 4-15 Minami-Shinagawa, Shinagawa-ku, Tokyo Japan Paint Co., Ltd. Tokyo office

Claims (3)

[Claims] 1. The following components (I) to (III): (I) Acrylic copolymer resin containing hydrolyzable alkoxysilane, (II) Acrylic copolymer resin containing no hydrolyzable alkoxysilane, and (III) A water-based coating composition containing a cross-linking agent (provided that at least one of components (I) and (II) contains an acid group and a hydroxyl group), which is neutralized with a basic substance. A coating composition characterized by being present. 2. The following components (I) to (III): (I) Acrylic copolymer resin containing hydrolyzable alkoxysilane, (II) Acrylic copolymer resin containing no hydrolyzable alkoxysilane, and (III) A crosslinking agent (however, at least one of components (I) and (II) contains an acid group and a hydroxyl group) is mixed, neutralized with a basic substance, and water is added. A method for producing a coating composition. 3. The following components (I) to (III): (I) Acrylic copolymer resin containing hydrolyzable alkoxysilane, (II) Acrylic copolymer resin containing no hydrolyzable alkoxysilane, and (III) Aqueous dispersion obtained by mixing a crosslinking agent (provided that at least one of components (I) and (II) contains an acid group and a hydroxyl group), neutralizing with a basic substance, and then adding water. A method for forming a matte coating film, which comprises coating with a liquid.