JP3349583B2 - Matte electrodeposition coating resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for a matte electrodeposition paint, and more particularly to a resin composition for a matte electrodeposition paint which is most suitable for aluminum or aluminum alloy products, especially aluminum building materials.

[0002]

2. Description of the Related Art In recent years, due to the demands of the times, in electrodeposition coating, matte electrodeposition coating capable of forming a coating film having a matte appearance has been widely practiced. These methods use an electrodeposition coating composition reacted under specific conditions without adding a special matting agent to the electrodeposition coating liquid. For example, the technique described in Japanese Patent Publication No. 60-19942 corresponds to this.

Further, there has been proposed a matte electrodeposition coating method using an anionic electrodeposition coating material comprising a water-soluble or water-dispersible acrylic copolymer having an alkoxysilane group in a side chain and an amino resin (particularly). Kosho 62-24519
Reference). However, the above-mentioned matte electrodeposition coating method has become increasingly difficult to withstand the strictly required quality of the electrodeposition coating film. For example, if the electrodeposition coating liquid is left for a long time, or if the electrodeposition coating is repeated while replenishing the same electrodeposition coating liquid with the original coating liquid, the appearance of the obtained electrodeposition coating film is reduced to the required coating film thickness. If it is attempted to maintain the surface of the electrodeposition coating liquid, the coating will become rough and the gloss will fluctuate.

As a method for controlling the gloss of a matte electrodeposition coating method, a resin composition for electrodeposition coating and a method for producing the same have been improved.
Japanese Patent No. 42770, Japanese Patent Application Laid-Open No. 5-171100 and the like correspond to this. However, in these methods, the initial gloss can be controlled, but (1) there is a difference in the co-progression of the mixed components in the electrodeposition coating liquid, so that a difference in gloss occurs depending on the electrodeposition conditions, and An electrodeposition coating composition having a component containing no group reduces coating film performance, especially solvent resistance, and (3) disperses particles become unstable because it does not contain a hydroxyl group or a carboxyl group, resulting in coarse resin particles. There are disadvantages such as precipitation of the resin in the liquid.

[0005]

DISCLOSURE OF THE INVENTION The present invention is directed to the disadvantages of the electrodeposited coating film obtained by the above-mentioned conventional electrodeposition coating method, namely, the roughening and gloss of the coating film due to the change with time when the electrodeposition coating liquid is used. Electrodeposition coating with excellent properties that eliminates problems such as fluctuations in appearance, coating performance such as solvent resistance and chemical resistance, and coating liquid stability such as precipitation. It is an object of the present invention to provide a resin composition for electrodeposition paint capable of forming a film.

[0006]

Means for Solving the Problems The present invention, which achieves the above object, comprises: A (a) a water-soluble or water-dispersible vinyl copolymer having a carboxyl group and a hydroxyl group in a side chain; and (b) a melamine resin. And an aqueous emulsion composition obtained by copolymerizing an aqueous emulsion composition having a carboxyl group partially neutralized with an organic amine and a vinyl monomer component containing B (c) unsaturated carboxylic acid as an essential component. (D) a cycloalkyl group-containing polymerizable monomer using the water-dispersible copolymer or a salt thereof as an emulsifier;
A glycidyl group-containing polymerizable monomer relates formed Ru glossy <br/> off electrodeposition coating resin composition from the emulsion composition of the copolymer obtained by emulsion polymerization in an aqueous medium.

[0007] The feature of the present invention is that the aqueous emulsion of A has the following composition ratio with respect to the composition ratio of the aqueous emulsion composition of A and the emulsion composition of the copolymer of B constituting the above-mentioned resin composition for a matte electrodeposition paint. (B) 40 to 80 parts by weight of a water-soluble or water-dispersible vinyl copolymer having a carboxyl group and a hydroxyl group in the side chain having an acid value of 15 to 160 and a hydroxyl value of 20 to 250 as a solid content; And the solid content of the emulsion composition of the copolymer (B) is 5 to 30 parts by weight based on 100 parts by weight of the solid content of the aqueous emulsion (A).
In matte electrodeposition coating resin composition in parts by weight.

[0008]

The electrodeposition coating liquid using the matte electrodeposition coating resin composition of the present invention does not precipitate even after a long period of standing, and the same coating liquid is used for the same electrodeposition coating liquid. Even after repeating electrodeposition coating while replenishing, the electrodeposition coating film has a beautiful appearance with stable low gloss without rough skin and unevenness,
The result is that the thickness of the coating film is also sufficiently satisfied. In particular, the copolymer constituting the emulsion composition of the copolymer B is obtained by polymerizing the vinyl monomer component having a carboxyl group (c). Coating after baking by mixing a self-crosslinkable water-dispersible vinyl copolymer by the reaction of a carboxyl group and a glycidyl group by polymerization of the polymer obtained by the above and the glycidyl group-containing monomer of (e). It is presumed that a beautiful low-gloss film having irregularities is formed on the upper surface, and that a film-forming property is imparted by introducing the cycloalkyl group-containing monomer unit (d) into the copolymer. You.

The resin composition for an electrodeposition coating composition of the present invention is specifically described below. The aqueous emulsion composition (A) of the present invention is known per se as a resin composition for electrodeposition paint. Examples of the carboxyl group-containing monomer constituting the water-soluble or water-dispersible vinyl copolymer having a carboxyl group and a hydroxyl group in the side chain of the component (a) include acrylic acid, α-chloroacrylic acid, and methacrylic acid. , Itaconic acid, maleic anhydride, maleic acid, fumaric acid, crotonic acid, citraconic acid, mesaconic acid, etc., alone or in combination, or a functional derivative thereof having at least one carboxyl group, such as an unsaturated polymerizable diamine. Or partial esters or amides of polycarboxylic acids. As the hydroxyl group-containing monomer constituting the component (a), 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate,
Examples include hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, diethylene glycol monoacrylate, and diethylene glycol monomethacrylate.

Further, a copolymerizable vinyl group-containing monomer which is copolymerized with a carboxyl group-containing monomer and a hydroxyl group-containing monomer constituting the water-soluble or water-dispersible vinyl copolymer of the component (a). As a body, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, butyl acrylate, butyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, Hexyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, heptyl acrylate, heptyl methacrylate, etc. Similar esters can be used with up to carbon atoms to about 20. Further, there are styrene, α-alkylstyrene, α-chlorostyrene, vinyltoluene, acrylonitrile, vinyl acetate and the like.

The carboxyl group-containing monomer, hydroxyl group-containing monomer and other monomers are converted to a desired acid value of 15
In order to obtain a copolymer having a hydroxyl value of from 160 to 160 and a hydroxyl value of from 20 to 250, the copolymer is copolymerized by an ordinary method in an organic solvent. The copolymer solution is converted into an aqueous emulsion by a conventional method, and the carboxyl group is partially neutralized with an organic amine. Conversion to an aqueous emulsion and neutralization with an amine may be performed after mixing with the melamine resin.

Next, as the melamine resin of the component (b),
It is sufficient that at least a part of the methylol group is alkoxylated with a lower alcohol. As the lower alcohol, one or more of methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and the like can be used.

As the organic amine, monomethylamine,
Alkylamines such as dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, monobutylamine, dibutylamine, tributylamine, etc., monoethanolamine, diethanolamine, triethanolamine, mono (2-hydroxypropyl) amine, di (2-
Alkanolamines such as hydroxypropyl) amine, tri (2-hydroxypropyl) amine, dimethylaminoethanol and diethylaminoethanol; alkylenepolyamines such as ethylenediamine, propylenediamine, diethylenetriamine and triethylenetetramine; and alkylenes such as ethyleneimine and propyleneimine. Examples include imines, piperazine, morpholine, pyrazine, pyridine and the like. The organic amine has a molar ratio of 0.1 to the carboxyl groups in the component (A) and the component (B).
What is necessary is just to add so that it may be set to 3-0.9.

The unsaturated carboxylic acid (c), which is a monomer used in the production of the emulsion composition of the copolymer B, is acrylic acid, α-chloroacrylic acid, methacrylic acid,
Itaconic acid, maleic anhydride, maleic acid, fumaric acid,
Crotonic acid, citraconic acid, mesaconic acid, etc. alone or in a mixture or a functional derivative thereof having at least one carboxyl group, such as an unsaturated polymerizable di-
Or a partial ester or amide of a polycarboxylic acid.

In addition to the unsaturated carboxylic acid monomer, a copolymerizable monomer having no carboxyl group can be used in combination. Examples thereof include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate,
n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, butyl acrylate, butyl methacrylate,
Lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, hexyl acrylate, 2-ethylhexyl acrylate,
There are 2-ethylhexyl methacrylate, heptyl acrylate, heptyl methacrylate and the like, and similar esters having up to about 20 carbon atoms in the alkyl group can be used. Further, styrene, α-alkylstyrene, α-
Chlorostyrene, vinyltoluene, acrylonitrile,
There are vinyl acetate and the like. Still other examples include acrylamide monomers such as acrylamide, methacrylamide, N-monomethylacrylamide, N-monomethylmethacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, and also 2-hydroxyethyl acrylate. Hydroxyl group-containing monomer such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, etc. Body and the like.

The water-soluble or water-dispersible copolymer (c) obtained by copolymerizing a vinyl monomer containing an unsaturated carboxylic acid as an essential component is a cycloalkyl (d) itself or a salt thereof. Since it is used as an emulsifier when emulsion-polymerizing the group-containing polymerizable monomer and the glycidyl group-containing polymerizable monomer (e), it is preferable to be produced by emulsion polymerization.

Examples of the (d) cycloalkyl group-containing polymerizable monomer include cyclohexyl acrylate, cyclohexyl methacrylate, methyl cyclohexyl acrylate, methyl cyclohexyl methacrylate, tertiary butyl cyclohexyl acrylate, and tertiary butyl cyclohexyl methacrylate. No.

Examples of the glycidyl group-containing polymerizable monomer (e) include glycidyl acrylate, glycidyl methacrylate, 2-methyl glycidyl acrylate, 2-methyl glycidyl methacrylate, and the like .

When copolymerizing the cycloalkyl group-containing polymerizable monomer (d) and the glycidyl group-containing polymerizable monomer (e), other copolymers used in the polymerization of the unsaturated carboxylic acid (c) are used. A monomer of the same type as the copolymerizable monomer may be blended.

The aqueous emulsion composition of the copolymer (B) is characterized in that the free carboxylic group of the unsaturated carboxylic acid, which is an essential component of (c), and the glycidyl group of the glycidyl group-containing polymerizable monomer of (e) are It is considered that in the copolymer of the monomers, the monomers react with each other and crosslink. The copolymer aqueous emulsion of B, for example acrylate cell Tsu preparative UW-10
(Nippon Shokubai Co., Ltd.), Acrylic UW-11 (Acrylic), Acrylic UW-12 (Acrylic), Acrylic UW-17 (Acrylic), and the like.

The acid value of the vinyl copolymer (a) is 1
It is preferably from 5 to 160, and a storage-stable electrodeposition coating liquid is obtained, and the water resistance and the like of the electrodeposition coating film are improved. If the acid value is less than 15, the storage stability of the electrodeposition coating liquid is poor, and precipitation and separation occur, while if it exceeds 160, the water resistance of the electrodeposition coating film is poor.
The hydroxyl value of the vinyl copolymer (a) is 20
In the case of ~ 250, the hardness, boiling water resistance and water resistance of the electrodeposition coating film are further improved, which is preferable. If the hydroxyl value is less than 20, the hardness of the electrodeposition coating film and the boiling water resistance are lowered, and if it is more than 250, the water resistance is inferior and thus it is not practical.

In the aqueous emulsion A of the composition of the present invention, the water-soluble or water-dispersible vinyl copolymer having a carboxyl group and a hydroxyl group as a component in the side chain of the aqueous emulsion of A is 40 to 80. The melamine resin of the component (b) is preferably 20 to 60 parts by weight. The water-dispersible vinyl copolymer of the component B is preferably 5 to 30 parts by weight with respect to 100 parts by weight of the component A comprising the components (a) and (b) in order to obtain a matte electrodeposition coating solution. .

When the proportion of the vinyl copolymer (a) as a solid content is 40 to 80 parts by weight, the water dispersibility of the resin liquid becomes particularly good, and a stable emulsion is formed.
If the proportion of the vinyl copolymer (a) is less than 40 parts by weight, the dispersibility in water is reduced, and a stable emulsion is not formed. If the proportion exceeds 80 parts by weight, sufficient coating performance cannot be obtained. Component B has a content of 5 to 3 based on a total of 100 parts by weight of the vinyl copolymer (a) and the melamine resin (b).
In the case of 0 parts by weight, a stable matting effect can be obtained. This B
If the amount of the component is less than 5 parts by weight, a satisfactory matting effect cannot be obtained, and if the amount exceeds 30 parts by weight, the electrodeposition coating film becomes rough.

[0024]

The present invention will be described in more detail with reference to examples and comparative examples of the present invention, but the present invention is not limited thereto. Parts in Examples, Comparative Examples and Application Examples are parts by weight unless otherwise specified.

EXAMPLE 1 10 parts of acrylic acid, 15 parts of 2-hydroxyethyl methacrylate, 15 parts of styrene and 15 parts of octyl acrylate were placed in a reaction vessel equipped with a stirrer, a thermometer and a reflux condenser.
Parts, 10 parts of butyl acrylate, 35 parts of methyl methacrylate, 1.5 parts of azobisisobutyronitrile, 8 parts of ethylene glycol monobutyl ether, and 35 parts of isopropyl alcohol, and the mixture was stirred at a reflux temperature for 6 hours to give carboxyl groups and A water-dispersible vinyl copolymer solution having a hydroxyl group in the side chain (acid value 78, hydroxyl value 64) was obtained.

Next, 43 parts of methylol melamine resin mixed with methoxybutoxy (trade name: MX-40, manufactured by Sanwa Chemical Co., Ltd.) was added to the copolymer solution, and the mixture was stirred and mixed well. 0 parts was added, and 214 parts of deionized water was further added to emulsify.

To this emulsion, 17 parts of a cross-linkable water-dispersible vinyl copolymer (trade name: ACRYSET UW-11, nonvolatile component 50%, manufactured by Nippon Shokubai Co., Ltd.) are added, and mixed by stirring. Obtained. Next, 270 parts of the matte electrodeposition coating composition was mixed with 720 parts of deionized water, and further 12 parts of ethylene glycol monobutyl ether and 1 part of dimethylaminoethanol were added to prepare a matte electrodeposition coating liquid.

The amounts of the components (a) and (b) of the components A and the components B used in Example 1 are shown in Table 1 below. Table 1
In the column of the B component, the values in parentheses are the amount of the solid component in the B component (50% by weight of the non-volatile component) and the amount of the solid component of the A component (the amount of the copolymer of the a component and the amount of the b component). (Sum of the amount of the alkoxylated methylol melamine resin) and the percentage by weight. In Example 1, the weight of the copolymer of the component a was 100 parts, the weight of the component b was 43 parts, and the solid content of the component B was 8.5 parts. Therefore, the above ratio was (8.5 / 1).
00 + 43) × 100% = 5.9%.

Example 2 Instead of the 2-hydroxyethyl methacrylate shown in Example 1, 2-hydroxyethyl acrylate was used.
A matte electrodeposition coating liquid was prepared under the same conditions as in Example 1 except that acrylic acid, triethylamine, a crosslinked water-dispersible vinyl copolymer, and an alkoxylated methylol melamine resin were varied as shown in Table 1. .

Examples 3 to 5 and Comparative Examples 1 to 3 Acrylic acid, 2-hydroxyethyl methacrylate, 2
-Hydroxyethyl acrylate, triethylamine,
A matte electrodeposition coating solution was prepared under the same conditions as in Example 1 or Example 2 except that the alkoxylated methylol melamine resin and the crosslinked water-dispersible vinyl copolymer were varied as shown in Table 1.

APPLICATION EXAMPLES Anodizing is performed on each of the matte electrodeposition coating solutions prepared in Examples 1 to 5 and Comparative Examples 1 to 3 by anodizing according to a conventional method, and an aluminum plate which is further subjected to inorganic electrolytic coloring is used as an anode. , 18-8
A stainless steel plate was connected to the cathode and immersed, and a DC voltage of 180 V was applied between both electrodes for 2 minutes. The temperature of the electrodeposition coating solution at this time was all 20 ° C. After completion of the electrodeposition coating, take out the aluminum plate and wash it thoroughly with water.
Hot air drying was performed for 0 minutes. As a result, the characteristics of the matte electrodeposition coating film formed on each aluminum plate were as shown in Table 1. The test methods for each of the physical properties of the coating film shown in Table 1 are as follows. 1. Coating thickness: According to Permascope E-110B (manufactured by Fisher). 2. Gloss: Gloss meter ｛Digital variable angle gloss meter UGV-5D
Using a Suga Test Machine Co., Ltd., 60 ° specular gloss was measured. 3. Appearance skin: Judged visually. The symbol is 〇 = good, × = rough skin

[0032]

[Table 1]

[0033]

As described above, the present invention is constituted as described above, so that the coating film formed is a stable and beautiful matte electrodeposition coating film with no rough skin and has a sufficient coating film thickness. Satisfied and extremely effective in industry.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // (C09D 201/06 C09D 161: 32 161: 32 163: 00 163: 00) (56) References JP-A-62-18479 (JP, A) JP-A-4-4270 (JP, A) JP-A-2-218769 (JP, A) JP-A-63-146971 (JP, A) JP-A-63-48367 (JP, A) JP-A-60-19942 (JP, A) JP-A-50-15251 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 5/00-201/10

Claims (1)

(57) [Claims] 1. A (a) a water-soluble or water-dispersible vinyl copolymer having a carboxyl group and a hydroxyl group in a side chain, and (b) a melamine resin, wherein the carboxyl group is partially contained by an organic amine. A water-soluble or water-dispersible copolymer obtained by copolymerizing the aqueous emulsion composition and a vinyl monomer component containing B (c) unsaturated carboxylic acid as an essential component, or a salt thereof as an emulsifier, (D) a cycloalkyl group-containing polymerizable monomer,
(E) in the glycidyl group-containing polymerizable monomer matte electrodeposition coating resin composition <br/> Ru formed from the emulsion composition of the copolymer obtained by emulsion polymerization in an aqueous medium, aqueous A D
The marjon has a solid content of (a) having an acid value of 15 to 160,
Carboxyl groups having a hydroxyl number of 20 to 250 and
Water-soluble or water-dispersible beads having a droxyl group in the side chain
Melamine tree of (b) 40 to 80 parts by weight of benzyl copolymer
Aqueous emulsion of A comprising 20 to 60 parts by weight of fat
Of copolymer of B to 100 parts by weight of solid content
The solid content of the composition is 5 to 30 parts by weight.
Characteristic matte electrodeposition coating resin composition.