JPH08100138A - Matte electrodeposition coating composition - Google Patents

Abstract

PURPOSE: To obtain the subject composition, containing a binder comprising an aqueous copolymer containing fluorine and an acrylic copolymer respectively having specific substituent groups and useful for forming films, excellent in appearance, matte degree, and further weather and acid resistances, etc., without any unevenness of gloss. CONSTITUTION: This composition contains a mixture of (A) 40-80wt.%, preferably 50-75wt.% aqueous copolymer, containing fluorine and having carboxyl and hydroxyl groups with (B) 60-20wt.%, preferably 50-25wt.% acrylic copolymer having alkoxysilane groups and groups of the formula CONHCH2 OR (R is a 1-3C alkyl) as a binder. Furthermore, the component (A) has preferably 5-150 acid value, 25-120 hydroxyl value and 2000-150000 weight-average molecular weight. The component (B) preferably comprises 0.1-30wt.% copolymerizable unsaturated monomer containing the alkoxysilane group and 5-50wt.% α,β- monoethylenically unsaturated monomer of the formula CH2 =C(R<1> )CONHCH2 OR (R<1> is H or methyl) as essential components and the balance of other unsaturated monomers.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is capable of forming a coating film which is excellent in appearance and matting degree, has no gloss unevenness, and has various chemical properties such as weather resistance, acid resistance and yellowing resistance. It relates to a possible matte electrodeposition coating composition.

[0002]

2. Description of the Related Art Conventionally, in a water-based paint in which a resin having a carboxyl group is neutralized with an organic amine or ammonia, a conductive object represented by a metal is used as an anode and a voltage is applied between the cathode and the cathode. Therefore, a method of forming an electrodeposition coating film on the surface of an object to be coated is widely used.

By the way, recently, a matte coating film which gives a calm atmosphere due to the tiredness of metallic luster has been demanded. Conventionally, as an electrodeposition coating composition for forming a matte coating film, (a) a composition containing fine powder such as polyethylene (for example, JP-A-60-13546).
No. 6), a composition containing (b) crosslinked resin particles (for example, JP-A-63-63760) and the like are known as typical ones.

Recently, in order to improve weather resistance,
(C) A composition containing a fluorine-containing copolymer as a binder (for example, JP-A-4-202382) is also known.

[0005]

However, the composition (a) has problems that the matting effect is poor in sustainability and gloss unevenness is likely to occur. On the other hand, the composition (B) has a problem that the coating film becomes cloudy or conversely the matte effect cannot be obtained unless the difference in refractive index between the binder and the crosslinked resin particles is sufficiently controlled. Further, since the composition of (c) uses the microgel, there is the same problem as the composition of (b).

[0006] Conventional electrodeposition coating compositions usually use a melamine resin or a blocked polyisocyanate as a cross-linking agent. Therefore, for example, when a melamine resin is used, the acid resistance is deteriorated and the blocked polyisocyanate is used. When isocyanate is used, there are problems such as yellowing. The present invention overcomes the problems of the conventional matte electrodeposition coating compositions as described above, that is, excellent in appearance, matting degree, no gloss unevenness, weather resistance, acid resistance, yellowing resistance, etc. It is an object of the present invention to provide a matte electrodeposition coating composition capable of forming a coating film excellent in various chemical properties.

[0007]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventors have found that an aqueous fluorocopolymer having a specific substituent and an acrylic copolymer having a specific substituent are used. The present invention has been completed by finding that the above object can be achieved by using a binder comprising the following in an electrodeposition coating composition.

That is, the matte electrodeposition coating composition of the present invention is
(A) 40 to 80% by weight of an aqueous fluorine-containing copolymer having a carboxyl group and a hydroxyl group, (B) an alkoxysilane group and a general formula —CONHCH ₂ OR (wherein R is an alkyl group having 1 to 3 carbon atoms). The present invention is characterized by containing a binder consisting of 60 to 20% by weight of an acrylic copolymer having a group represented by

The present invention will be described in detail below. The aqueous fluorine-containing copolymer having a carboxyl group and a hydroxyl group (hereinafter referred to as "aqueous fluorine-containing copolymer") used as one component of the binder in the present invention contains a carboxyl group and a hydroxyl group in the molecule and is neutralized. It is a resin that dissolves in water or disperses stably in water when neutralized with an agent.

The acid value of the aqueous fluorocopolymer is preferably 5 to 150, particularly preferably 15 to 100. If the acid value is smaller than the above range, the storage stability of the coating composition tends to decrease, and conversely if the acid value increases, the water resistance of the coating film tends to deteriorate. The hydroxyl value of the aqueous fluorocopolymer is preferably 25 to 120, particularly preferably 40 to 10.
0. When the hydroxyl value is smaller than the above range, the crosslinkability with the acrylic copolymer component described below becomes insufficient, and the various physical strengths of the resulting coating film tend to decrease, and it is difficult to obtain a matte coating film. On the contrary, when it is large, the water resistance of the coating film tends to be poor.

The weight average molecular weight of the aqueous fluorocopolymer is preferably 2,000 to 150,000, particularly preferably 4,000 to 100,000. As such an aqueous fluorine-containing copolymer, a commercially available product, which is a copolymer containing fluoroolefin and cycloalkyl vinyl ether as main components, is a product name "Lumiflon 926" manufactured by Asahi Glass Co., Ltd.
(Acid value of about 20, Hydroxyl value of about 60); Fluoronate JZ-443 manufactured by Dainippon Ink and Chemicals, Inc., which is a copolymer containing fluoroolefin, vinyl ether and vinyl ester as main components (acid value of about 8, Hydroxyl value about 85);
Product name "Zeffle EV-120" manufactured by Daikin Industries, Ltd., which is a copolymer containing fluoroolefin, vinyl ether, and vinyl ester as main components (acid value about 48, hydroxyl value about 6
0), "Zeffle EV-210" (acid value of about 80, hydroxyl value of about 89); a trade name "Sefraral Coat XA" manufactured by Central Glass Co., which is a copolymer having fluoroolefin, vinyl ether, allyl ether, and vinyl ester as main components.
-500-1 "(acid value about 35, hydroxyl value about 37)," Cefural coat XA-500-2 "(acid value about 33, hydroxyl value about 46)," Cefural coat XA-500-8 "(acid value about 45 , A hydroxyl value of about 52), "Sephralcoat XA-
500-13 "(acid value about 48, hydroxyl value about 52) and the like are known as typical ones.

Further, JP-A-5-98207 and JP-A-3
-181540, JP-A-2-70706, JP-A-2
Various aqueous fluorine-containing copolymers described in JP-A-55776, JP-A-62-243603, JP-A-62-50306, JP-A-58-136605 and the like can also be used. By using such an aqueous fluorocopolymer as one component of the binder in the present invention, a matte coating film having excellent weather resistance can be obtained.

An acrylic copolymer having an alkoxysilane group used as one component of the binder in the present invention and a group represented by the general formula --CONHCH ₂ OR (wherein R is an alkyl group having 1 to 3 carbon atoms). The combination (hereinafter referred to as “acrylic copolymer”) is, for example, a copolymerizable unsaturated monomer having an alkoxysilane group and a general formula —CONHCH ₂ O.
Α, β-monoethylenically unsaturated monomer having a group represented by R (wherein R is an alkyl group having 1 to 3 carbon atoms) [preferably, general formula CH ₂ ═C (R ¹ ) CONHCH ₂
OR (in the formula, R is an alkyl group having 1 to 3 carbon atoms, R
¹ is a hydrogen atom or a methyl group) α, β-monoethylenically unsaturated monomer represented by] as an essential component,
It is obtained by subjecting a copolymerizable unsaturated monomer mixture, the balance of which is other copolymerizable unsaturated monomer, to a copolymerization reaction by a known solution polymerization method, emulsion polymerization method, non-aqueous dispersion polymerization method or the like.

As the above-mentioned copolymerizable monomer having an alkoxysilane group, divinyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltributoxysilane, γ-methacryloxypropyltrimethoxysilane, Typical examples include γ-methacryloxypropyltriethoxysilane, trimethoxyallylsilane, triethoxyallylsilane, (meth) acryloylmethyltrimethoxysilane, and (meth) acryloylethyltrimethoxysilane.

The above-mentioned general formula --CONHCH ₂ OR
Examples of the α, β-monoethylenically unsaturated monomer having a group represented by the formula (wherein R is an alkyl group having 1 to 3 carbon atoms) include N-methoxymethyl (meth) acrylamide and N-ethoxymethyl ( (Meth) acrylamide, N-
n-propoxymethyl (meth) acrylamide, Ni
-Propoxymethyl (meth) acrylamide.

Other copolymerizable unsaturated monomers constituting the balance of the copolymerizable unsaturated monomer mixture include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate and hydroxypentyl ( (Meth) acrylate, neopentyl glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, glycerin mono (meth) acrylate, and other copolymerizable unsaturated monomers having a hydroxyl group, (meth) acrylic acid,
Copolymerizable unsaturated monomer having a carboxyl group such as crotonic acid, itaconic acid, maleic acid and fumaric acid, methyl (meth) acrylate, ethyl (meth) acrylate,
Alkyl ester of (meth) acrylic acid such as propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, lauryl (meth) acrylate, glycidyl (meth) acrylate, cyclohexyl (meth) acrylate, styrene, vinyltoluene Typical examples thereof include (meth) acrylonitrile and vinyl acetate.

The acrylic copolymer used as one component of the binder in the present invention is a copolymer obtained by copolymerizing these copolymerizable unsaturated monomer mixtures, and its weight average molecular weight is preferably 2, It is 000 to 100,000, and more preferably 10,000 to 50,000. The amount of the copolymerizable unsaturated monomer having an alkoxysilane group in the acrylic copolymer is preferably 0.1 to 30% by weight, particularly preferably 1 to 15% by weight. When the amount of the copolymerizable unsaturated monomer having an alkoxysilane group is less than the above range, it becomes difficult to obtain a matte coating film which is the object of the present invention, and when the amount is too large, it becomes difficult to obtain a uniform coating film. There is a tendency.

The general formula --CO in an acrylic copolymer
The amount of the α, β-monoethylenically unsaturated monomer having a group represented by NHCH ₂ OR is preferably 5 to 50% by weight,
It is particularly preferably 8 to 30% by weight. If the amount of the α, β-monoethylenically unsaturated monomer is less than the above range, the crosslinking reaction between the N-alkoxymethylamide group in the acrylic copolymer and the hydroxyl group in the aqueous fluorocopolymer and the acrylic copolymer will occur. The self-crosslinking reaction between N-alkoxymethylamide groups in the polymer becomes insufficient, various physical strengths of the resulting coating film tend to decrease, and a matte coating film tends to be difficult to obtain. On the other hand, if the amount is too large, gelation tends to occur during production of the acrylic copolymer.

It is not essential that the acrylic copolymer has a hydroxyl group, but it is suitable that the hydroxyl value of the acrylic copolymer is 10 to 100 in order to easily obtain a matte coating film. When the hydroxyl value is larger than the above range, the water resistance of the coating film is deteriorated, which is not preferable. The acid value of the acrylic copolymer is 0 to 100, more preferably 0 to 60. When the acid value is larger than the above range, the water resistance of the coating film is deteriorated, which is not preferable.

The matte electrodeposition coating composition of the present invention comprises 40 to 80% by weight, preferably 50 to 75% by weight, of the above-mentioned aqueous fluorocopolymer and acrylic copolymer 60 to 20% by weight.
%, Preferably 50 to 25% by weight, as a binder. When the amount of the aqueous fluorocopolymer is less than the above range, the weather resistance of the coating film is lowered, and the gloss of the coating film is too dull and rough, and the storage stability of the coating is lowered, and conversely. If the amount is too large, a coating film having a low matteness cannot be obtained, and therefore neither is preferable.

The matte electrodeposition coating composition of the present invention contains the above-mentioned binder, a neutralizing agent for making the binder water-soluble or water-dispersible, and an aqueous medium. Including various additives such as organic or inorganic color pigments, extender pigments, thickeners, defoamers, anti-settling agents, antifungal agents, curing catalysts and the like used in the electrodeposition coating composition of No. Further, a conventional matting agent such as crosslinked resin particles having an average particle diameter of 0.05 to 20 μm, and a crosslinking agent such as melamine resin or blocked polyisocyanate to the extent that they do not impair properties such as acid resistance and yellowing resistance are used together. It is also possible.

Typical examples of the neutralizing agent include organic amines such as monomethylamine, dimethylamine, triethylamine, diethylamine, triethylamine, monoisopropylamine and diethylaminoethanol, and ammonia. The amount of neutralizer used is
The binder is stable enough to be dissolved or dispersed in an aqueous medium, and usually 30 to 100% of the total theoretical neutralization amount is suitable.

The aqueous medium is water or a mixture of water and a water-miscible organic solvent. Representative examples of the water-miscible organic solvent include ethyl cellosolve, propyl cellosolve, butyl cellosolve, ethylene glycol dimethyl ether, diacetone alcohol, ethyl alcohol, ethyl acetate and methyl ethyl ketone.
If necessary, a small amount of a water-immiscible organic solvent such as xylene or toluene can be used together. The amount of the aqueous medium used is appropriately such that the solid content concentration of the electrodeposition coating composition in the electrodeposition coating bath is about 2 to 20% by weight, preferably 5 to 15% by weight.

Next, a method for electrodeposition coating an electrically conductive object using the electrodeposition coating composition of the present invention will be described. As the electrodeposition coating method, a conventionally known method can be directly adopted. That is, the electrodeposition coating composition of the present invention is kept in an electrodeposition coating bath at a temperature of about 15 to 35 ° C. to form a bath liquid, and a conductive coating object is dipped in the bath liquid to apply a coating voltage of about 50 to 400 V. The electrodeposition coating film is formed on the surface of the electroconductive object under a condition of preferably 70 to 300 V and an energization time of 30 seconds to 10 minutes, preferably 1 to 5 minutes. Then, if necessary, after washing with water and air-drying, 140 to 250 ° C, preferably 160 to 200 ° C
Then, it is heat-cured for about 10 to 60 minutes, preferably 20 to 40 minutes. In this way, an electrodeposition coating film having a desired matte effect is formed. Dry electrodeposition coating thickness is about 2-50μ
m, preferably 5 to 30 μm.

As the above-mentioned electrically conductive object to be coated, for example, a metal material such as iron, steel, aluminum, copper or the like, or the surface of these objects to be metal-plated or anodized is typical. However, there is no particular limitation as long as it is electrically conductive, and various types of objects to be coated can be applied. Next, the present invention will be described in more detail with reference to Examples. In addition, "part" and "%" in the examples are shown based on weight.

[0026]

【Example】

<Preparation of Acrylic Copolymer Varnish B-1> 46 parts of isopropyl alcohol and 14 parts of butyl cellosolve were charged into a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a cooling tube, and the temperature was raised to 85 ° C., followed by methacryloxy. Propyltrimethoxysilane 12 parts, N-methoxymethylacrylamide 10 parts, 2-hydroxyethyl methacrylate 2.3 parts, methyl methacrylate 25 parts, styrene 13
Parts, 37.7 parts ethyl acrylate and 0.7 parts azobisisobutyronitrile at a reaction temperature of 85.
The solution was added dropwise over 3 hours while maintaining the temperature at ℃.

One hour after the completion of the dropping, a mixture of 1.0 part of azobisisobutyronitrile and 5 parts of butyl cellosolve was added dropwise over 2 hours, and the reaction was continued for another 2 hours to give an acid value of 0 and a hydroxyl value of 10, Weight average molecular weight 24,000
0 acrylic copolymer was produced. Acrylic copolymer varnish B-1 was prepared by adding a mixed solvent of isopropyl alcohol and butyl cellosolve in a weight ratio of 2: 1 to the reaction product so that the nonvolatile content was 50%.

<Preparation of Acrylic Copolymer Varnish B-2>
After charging 46 parts of isopropyl alcohol and 14 parts of butyl cellosolve into the reaction vessel and heating to 85 ° C.,
Methacryloxypropyltrimethoxysilane 10 parts, N
-Ethoxymethyl acrylamide 30 parts, hydroxypropyl acrylate 7 parts, methyl methacrylate 23
Part, 10 parts of styrene, 20 parts of ethyl acrylate and 1.5 parts of azobisisobutyronitrile,
While maintaining the reaction temperature at 85 ° C., the mixture was added dropwise over 3 hours.

One hour after the completion of the dropping, a mixture of 1.0 part of azobisisobutyronitrile and 5 parts of butyl cellosolve was added dropwise over 2 hours, and the reaction was continued for another 2 hours to give an acid value of 0 and a hydroxyl value of 30, Weight average molecular weight 15,000
0 acrylic copolymer was produced. A mixed solvent of isopropyl alcohol and butyl cellosolve in a weight ratio of 2: 1 was added to the reaction product so that the nonvolatile content was 50% to prepare an acrylic copolymer varnish B-2.

<Preparation of Acrylic Copolymer Varnish B-3>
After charging 46 parts of isopropyl alcohol and 14 parts of butyl cellosolve into the reaction vessel and heating to 85 ° C.,
Methacryloxypropyltrimethoxysilane 7 parts, N-
30 parts of n-propoxymethyl acrylamide, 4.1 parts of 2-hydroxyethyl acrylate, 6.1 methacrylic acid
Parts, methyl methacrylate 12.8 parts, styrene 15
Part, 25 parts of ethyl acrylate and 0.7 part of azobisisobutyronitrile were added dropwise over 3 hours while maintaining the reaction temperature at 85 ° C.

One hour after the completion of the dropping, a mixture of 0.7 part of azobisisobutyronitrile and 5 parts of butyl cellosolve was added dropwise over 2 hours, and the reaction was continued for another 2 hours to give an acid value of 40 and a hydroxyl value of 20, Weight average molecular weight 22.0
No. 00 acrylic copolymer was produced. In the reaction product,
Acrylic copolymer varnish B-3 was prepared by adding a mixed solvent of isopropyl alcohol and butyl cellosolve in a weight ratio of 2: 1 so that the nonvolatile content was 50%.

<Preparation of Acrylic Copolymer Varnish B-4>
After charging 46 parts of isopropyl alcohol and 14 parts of butyl cellosolve into the reaction vessel and heating to 85 ° C.,
Vinyltriethoxysilane 5 parts, Nn-propoxymethylacrylamide 30 parts, 2-hydroxyethyl acrylate 8.3 parts, acrylic acid 2.6 parts, methyl methacrylate 16.6 parts, styrene 15.5 parts, ethyl acrylate 22 Part and 2.0 parts of azobisisobutyronitrile were added dropwise over 3 hours while maintaining the reaction temperature at 85 ° C.

One hour after the completion of the dropping, a mixture of 1.0 part of azobisisobutyronitrile and 5 parts of butyl cellosolve was added dropwise over 2 hours, and the mixture was further reacted for 2 hours to give an acid value of 20 and a hydroxyl value of 40, Weight average molecular weight 12,0
No. 00 acrylic copolymer was produced. In the reaction product,
Acrylic copolymer varnish B-4 was prepared by adding a mixed solvent of isopropyl alcohol and butyl cellosolve in a weight ratio of 2: 1 so that the nonvolatile content was 50%.

<Preparation of Acrylic Copolymer Varnish B-5>
In the method for preparing the acrylic copolymer varnish B-1, the reaction was carried out in the same manner except that 12 parts of methacryloxypropyltrimethoxysilane was changed to 0 part and 25 parts of methyl methacrylate was changed to 37 parts to obtain an acid value of 0 and a hydroxyl group. Value 10,
An acrylic copolymer having a weight average molecular weight of 23,000 was produced, and an acrylic copolymer varnish B-5 having a nonvolatile content of 50% was prepared.

<Preparation of Acrylic Copolymer B-6> In the method for preparing the acrylic copolymer varnish B-4, Nn-
Propoxymethyl acrylamide 30 parts to 0 parts, methyl methacrylate 16.6 parts to 31.6 parts, styrene 1
The reaction was carried out in the same manner except that 5.5 parts was changed to 17.5 parts and ethyl acrylate 22 parts was changed to 35 parts, and the acid value was 2
An acrylic copolymer having a hydroxyl value of 0, a hydroxyl value of 40 and a weight average molecular weight of 13,500 was produced to prepare an acrylic copolymer varnish B-6 having a nonvolatile content of 50%.

Examples 1 to 4 and Comparative Examples 1 to 5 The components shown in Table 1 (numerical values in the table are solid contents) were mixed, and then in a ratio of 0.6 equivalent to the carboxyl group of each copolymer. After adding triethylamine, the mixture was diluted with pure water to prepare an electrodeposition coating having a solid content of 10%. The aqueous fluorocopolymer varnish A-1 in Table 1 is a product name "Zeffle EV-210" manufactured by Daikin Industries, Ltd. (acid value 80, hydroxyl value 8
9), and the aqueous fluorocopolymer varnish A-2 is manufactured by Central Glass Co., Ltd. under the trade name of “Sefraral Coat XA-500-”.
2 "(acid value 33, hydroxyl value 46), the curing catalyst is King's trade name" Necure 2500X ", and the melamine resin is Sanwa Chemical's trade name" Nikalac MX ".
-40 ".

An aluminum plate treated with each electrodeposition coating and subjected to an anodic oxide film was used as an anode, and a direct current voltage of 160 V was applied to the aluminum plate.
It was electrodeposited for 50 seconds. Then, after washing with water, 30 at 180 ℃
It was baked for a minute to form a cured coating film. The appearance, matteness, glossiness, weather resistance, acid resistance, yellowing resistance, adhesion and hardness of each of the obtained coating films were evaluated by the following methods. The results are shown in Table 2. In Comparative Example 2, a practical cured coating film could not be formed. Appearance: The surface of the coating film was visually observed and checked for any abnormalities such as cissing, spots, dents, etc. ◎: No abnormality ◯: Very slight abnormality △: Some abnormality ×: Substantial abnormality Matte degree: 60 ° Glossiness measured by specular reflection Gloss unevenness: The surface of the coating film was visually observed to check if there was any gloss unevenness ◎: No gloss unevenness 〇: Very slight gloss unevenness △: Some gloss unevenness ×: There is considerable uneven gloss Weather resistance: 300 using a sunshine weatherometer
The gloss retention of the coating film after 0 hours was examined. ◎: 70% or more ◯: 69 to 50% △: 49 to 30% ×: 29% or less Acid resistance: 5% H ₂ SO ₄ (80 ° C) spot test 40 After 5 minutes, the surface of the coating film was visually observed and checked for spot marks. ◎: No abnormality ◯: Very slight abnormality △: Some abnormality ×: Substantial abnormality Yellowing resistance: Baking at 200 ° C for 30 minutes The color change of the appearance of the coating film was visually observed. ◎: No abnormality ◯: Very slight yellowing △: Slightly yellowing ×: Equivalent yellowing Adhesion: In accordance with JIS K5400, a goggles test was conducted at 1 mm intervals ◎ : 100/100 ◯: 99/100 to 95/100 Δ: 94/100 to 90/100 ×: 89/100 to 0/100 Hardness: According to JIS K5400 8.4, pencil hardness test at 20 ° C. Carried out

[0038]

[Table 1]

[0039]

[Table 2] As is clear from the data in Table 2, in each of the examples using the electrodeposition coating composition of the present invention, the matting degree, the uneven glossiness, the weather resistance, the acid resistance, the yellowing resistance, the adhesion, etc. are excellent. A coating film was obtained.

On the other hand, in Comparative Example 1 in which an acrylic copolymer containing no alkoxysilane group was used, no matte coating film was obtained. In Comparative Example 2 in which the acrylic copolymer containing no group represented by the general formula —CONHCH ₂ OR was used, a practical cured coating film could not be formed. Further, in Comparative Example 3 in which the amount of the aqueous fluorocopolymer was small, the coating film appearance, weather resistance and adhesion were deteriorated, and conversely in Comparative Example 4 in which the amount was excessive, a matte coating film could not be obtained. Further, in Comparative Example 5 in which the melamine resin was blended as a cross-linking agent without blending the acrylic copolymer, a glossy coating film was obtained, and the acid resistance was further poor.

[0041]

As described above, the electrodeposition coating composition of the present invention uses a binder comprising a specific aqueous fluorocopolymer (A) and a specific acrylic copolymer (B). Therefore, the effect of improving the weather resistance by the component (A), the formation of a gel structure in the particle by the alkoxysilane group in the component (B), and the hydroxyl group in the component (A) by the N-alkoxymethylamide group Due to the crosslinking reaction and the self-crosslinking reaction between N-alkoxymethylamide groups, a matte coating having no gloss unevenness can be obtained without separately adding a matting agent or a crosslinking agent. It has excellent yellowing properties.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mutsushi Takeishi 7-14 14-41 Shimonagata, Nishinasuno-machi, Nasu-gun, Tochigi Prefecture (72) Inventor Yuji Yamazaki 1920-1 Otawara-shi, Tochigi Prefecture Masaharu Yamada Tochigi 1961 Hashiba, Otawara-shi, Japan

Claims (3)

[Claims] 1. (A) 40 to 80% by weight of an aqueous fluorocopolymer having a carboxyl group and a hydroxyl group, (B) an alkoxysilane group and a general formula —CONHCH ₂
60 to 20% by weight of an acrylic copolymer having a group represented by OR (wherein R is an alkyl group having 1 to 3 carbon atoms)
A matte electrodeposition coating composition comprising a binder consisting of 2. The matte electrodeposition coating composition according to claim 1, wherein the component (A) is an aqueous fluorocopolymer having an acid value of 5 to 150 and a hydroxyl value of 25 to 120. 3. The component (B) comprises 0.1 to 30% by weight of a copolymerizable unsaturated monomer having an alkoxysilane group and a general formula CH ₂ ═C (R ¹ ) CONHCH ₂ OR (wherein R is
Is an alkyl group having 1 to 3 carbon atoms, and R ¹ is a hydrogen atom or a methyl group) and contains 5 to 50% by weight of an α, β-monoethylenically unsaturated monomer represented by
The matte electrodeposition coating composition according to claim 1, wherein the balance is an acrylic copolymer obtained from a copolymerizable unsaturated monomer mixture containing other copolymerizable unsaturated monomers.