JP2003129003A - Matte type anionic electrodeposition coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a matte type anionic electrodeposition coating material excellent in weather resistance and stability. SOLUTION: This coating material contains a vinyl copolymer resin (A) which is obtained by subjecting to a radical polymerization a fluorine-containing unsaturated monomer (a), an alkoxysilyl group-containing unsaturated monomer (b), a hydroxyl group-containing unsaturated monomer (c), a carboxyl group- containing unsaturated monomer (d) and other unsaturated monomer (e), and a crosslinking agent (B) having a functional group reactive with the hydroxyl group.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a matte type anionic electrodeposition coating composition having excellent weather resistance and coating stability.

[0002]

2. Description of the Related Art Conventionally, since aluminum has better workability at high temperatures than steel and the like, it is possible to relatively easily obtain a mold material having various cross-sectional shapes by hot extrusion. Further, aluminum has come to be widely used especially as a material related to building materials by utilizing the original excellent properties of aluminum such as light weight, easy workability and excellent corrosion resistance. Aluminum itself is not easily corroded by corrosive substances such as salt water resistance, but it is easily corroded by alkali resistance (mortar etc.), so usually after anodizing aluminum,
It is generally covered with an anion electrodeposition paint or the like.

As such an electrodeposition coating composition for aluminum materials, a combination of a resin having an alkoxysilyl group in the side chain and a resin having a different SP value is used as an invention of a matte anion electrodeposition coating composition.
There is a gazette. Further, a resin containing an alkoxysilyl group as a side chain and an acrylic monomer having a benzotriazole group (UVA monomer) as a monomer component and / or an acrylic monomer having a hindered amino group as an essential monomer component (HALS monomer) is used. The invention described in 2001-64568 is known as an invention relating to a matte-type anionic electrodeposition coating composition having good weather resistance when used. Further, in these inventions, the coating stability may be impaired if the amount of UVA monomer or HALS monomer added is increased in order to further improve the weather resistance.

Further, since two kinds of resins are combined, for example, when the coating frequency of the coated article is extremely low (sometimes referred to as a low speed tanover coating line), for a long period of time in the tank, As piping and filters are circulated, paint agglomerates may adhere to the wall surface inside the electrodeposition tank, and the trouble of cleaning paint agglomerates and clogging of the filter may cause the casing to be opened and the filter to be removed. Had to replace. Therefore, users have demanded a matte type anionic electrodeposition coating composition having high weather resistance and good coating stability.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a fluorine-containing unsaturated monomer (a) and an alkoxysilyl group-containing unsaturated monomer (b) A vinyl copolymer resin (A) obtained by copolymerizing a hydroxyl group-containing unsaturated monomer (c), a carboxyl group-containing unsaturated monomer (d), and another unsaturated monomer (e), and a cross-linking agent (B). By containing it, a matte type anionic electrodeposition coating having good weather resistance and coating stability can be obtained, and the present invention has been completed.

That is, the present invention is as follows: Fluorine-containing unsaturated monomer (a), alkoxysilyl group-containing unsaturated monomer (b), hydroxyl group-containing unsaturated monomer (c), carboxyl group-containing unsaturated monomer (d), and other unsaturated monomer (e) as radicals A matte type anionic electrodeposition coating composition containing a vinyl copolymer resin (A) obtained by copolymerization and a crosslinking agent (B) having a functional group that reacts with a hydroxyl group. 2. The fluorine-containing unsaturated monomer (a) is represented by the following formula (1), and is a matte type anionic electrodeposition coating composition according to item 1.

[0007]

Formula (1) (In the formula, A is hydrogen or a methyl group, m is an integer of 0 to 4,
n represents an integer of 1 to 12) 3. The matte type anionic electrodeposition coating composition according to item 1, wherein the fluorine-containing unsaturated monomer (a) is 2-perfluorooctyl methacrylate or trifluoroethyl methacrylate.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail.

Vinyl Copolymer Resin (A) The vinyl copolymer resin (A) is a fluorine-containing unsaturated monomer (a), an alkoxysilyl group-containing unsaturated monomer (b), a hydroxyl group-containing unsaturated monomer (c), It is a resin obtained by radical copolymerizing a carboxyl group-containing unsaturated monomer (d) and another unsaturated monomer (e).

Examples of the fluorine-containing unsaturated monomer (a) include perfluorobutylethyl acrylate, perfluoroisononylethyl acrylate, 2-perfluorooctylethyl acrylate and perfluorobutyl. Ethylmethacrylate, trifluoroethylmethacrylate, perfluoroisononylethylmethacrylate,
Perfluorooctylethyl methacrylate and the like are listed, and specific commercially available products include FAMAC and FAMA.
CM (above, Nippon Mektron, trade name, 2-perfluoroalkyl methacrylate), light ester M
-3F (Kyoeisha Chemical Co., Ltd., trade name, trifluoroethyl methacrylate).

Examples of the alkoxysilyl group-containing unsaturated monomer (b) include γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-acryloxypropylmethyldimethoxysilane and γ-methacryloxypropyl. Examples thereof include trimethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, vinyltrimethoxysilane and the like.

Examples of the hydroxyl group-containing unsaturated monomer (c) include, for example, hydroxyethyl (meth) acrylate,
Hydroxypropyl (meth) acrylate, hydroxybutyl (meth) arylate, (poly) ethylene glycol
Rumono (meth) acrylate, (poly) propylene glycol mono (meth) acrylate, hydroxybutyl vinyl ether, (meth) allyl alcohol, and the above hydroxyl group-containing vinyl monomers and β-pro Piolactone, dimethylpropiolactone, butyrolactone, γ-
Valerolactone, γ-caprolactone, γ-caprylolactone, γ-laurolactone, ε-caprolactone,
Trade names such as reaction products with lactone compounds such as δ-caprolactone include Praxel FM1 (trade name, manufactured by Daicel Chemical Co., Ltd., caprolactone-modified (meth) acrylic acid hydroxyesters), Praxel FM2 (same left),
Praxel FM3 (same left), Praxel FA-1 (same left), Praxel FA2 (same left), Praxel FA3
(Same as left) etc.

Unsaturated monomer containing carboxyl group (d)
As, for example, (meth) acrylic acid, crotonic acid,
Itaconic acid, maleic acid, fumaric acid, Praxel FM1
A (hereinafter, manufactured by Daicel Chemical Industries, caprolactone-modified carboxyl group-containing (meth) acrylic monomer, trade name),
Examples include Praxel FM4A and Praxel FM10A.

Specific examples of the other unsaturated monomer (e) include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, pentyl acrylate, pentyl methacrylate and hexyl acrylate. , Hexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate and lauryl methacrylate and the like, monoesters of acrylic acid or methacrylic acid with monoalcohols having 1 to 24 carbon atoms, glycidyl acrylate and glycidyl group. Radical polymerizable unsaturated monomer, acrylonitrile, acrylamide, N-methylacrylamide, N Methylolacrylamide, N
-Addition of caprolactone with nitrogen-containing radically polymerizable unsaturated monomer such as butoxymethyl acrylamide and dimethylaminoethyl methacrylate, styrene, phenylethyl (meth) acrylate, vinyl acetate, vinyl chloride, 2-hydroxyethyl (meth) acrylate Products (eg, FM series such as Praxel FA, Praxel FM2, and Praxel FM3 as trade names manufactured by Daicel Chemical Industries, Ltd.) and the like. These can be used alone or in combination of two or more. Other examples include crosslinkable unsaturated monomers such as allyl methacrylate and 1,6-hexanediol diacrylate, and polymerized products.

The mixing ratio of these unsaturated monomers is such that the fluorine-containing unsaturated monomer (a) is 0.1 to the total solid content of the monomers constituting the vinyl copolymer resin (A).
20% by weight, alkoxysilyl group-unsaturated monomer (b) in the range of 0.1 to 20% by weight, hydroxyl group-containing unsaturated monomer (c) in the range of 5 to 25 parts by weight, carboxyl group-containing unsaturated monomer The range of 5 to 25 parts by weight of (d) and 50 to 80% by weight of the other unsaturated monomer (e) is preferable.

As a method for synthesizing an acrylic resin by a radical copolymerization reaction using the above-mentioned monomers, conventionally known methods such as solution polymerization method, bulk polymerization, emulsion polymerization and suspension polymerization can be mentioned.

Cross-linking agent (B) The cross-linking agent (B) is, for example, one or more of methylol groups of melamine resin such as methanol, ethanol, propanol, butanol, and octyl alcohol 2-ethylhexyl alcohol. Those modified with the monohydric alcohol can be used.

The melamine resin is preferably one having 1 to many (about 2 to 5) nuclei, which accounts for 50% by weight or more. Further, the melamine resin may contain other functional groups such as imino group and methylol group. In the anionic thermosetting electrodeposition coating composition containing the product of the present invention, an ether group modified with a C ₃ or higher monohydric alcohol, particularly a C _{4 to} C ₁₈ monohydric alcohol, has an average of about 3 per nucleus of the triazine ring. 2.0
It is preferable to contain one or more, especially 2.0 to 5.0.

Blocking polyisocyanates can be used as the cross-linking agent (B). For example, "aliphatic or alicyclic polyisocyanate compounds such as isophorone diisocyanate and hexamethylene diisocyanate, lactones such as ε-caprolactone and the like can be used. Those blocked with alcohols such as methanol, ethanol, propanol, butanol and pentanol and oximes such as methylethylketoxime and methylisobutylketoxime can be used.

Vinyl copolymer resin (A), crosslinking agent (B)
The compounding ratio of the former is the latter / the latter is 60/40 to 85 /
The range of 15 is preferable, and the crosslinking agent (B) is added to 100 parts by weight of the vinyl copolymer resin (A) and the crosslinking agent (B) in total.
If the blending amount exceeds 40 parts by weight, the stability of the paint is impaired,
If it is less than 15 parts by weight, the curability is insufficient. that's all,
A resin comprising a vinyl copolymer resin (A) and a crosslinking agent (B) can be dispersed in water by adding a basic compound and neutralizing it to prepare an aqueous emulsion.

Examples of such basic compounds include ethylamine, propylamine, butylamine, benzylamine, monoethanolamine, neopentanolamine,
Primary monoamines such as 2-aminopropanol and 3-aminopropanol; diethylamidiethanolamine, di-n- or di-iso-propanolamine, N-
Secondary monoamines such as methylethanolamine and N-ethylethanolamine; dimethylethanolamine,
Tertiary amines such as trimethylamine, triethylamine, triisopropylamine, methyldiethanolamine, dimethylaminoethanol, etc .; polyethylene triethylamine such as diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropylamine, etc. 1 or 2 There is an amine-based neutralizer selected in combination with the above.
Add deionized water and disperse in water while stirring with a despar to prepare an aqueous emulsion.

Here, the matte anionic electrodeposition coating composition of the present invention contains, if necessary, pigments, dyes, curing catalysts, flow control agents,
An ultraviolet absorber or the like can be added. As a method for producing a matte anionic electrodeposition coating composition, the above neutralizing agent (for example, diethylamine, triethylamine, etc.) is used so that the amount becomes 0.3 to 0.5 equivalent to the carboxyl group of the vinyl copolymer resin (A). After blending the crosslinking agent (B) and dispersing in water, deionized water is added to obtain a matte type anionic electrodeposition coating composition having a solid content of 5% by weight to 20% by weight.

In order to form a coating film using the matte anionic electrodeposition coating composition, the matte anion electrodeposition coating composition obtained above is used as a bath (in a bath), and the aluminum is placed in the bath. After immersing the material, anion electrodeposition coating is performed so that the dry film thickness is about 5 to 30 μm, without water washing (non-rinsing) or water washing (rinsing), and then setting at room temperature, followed by baking ( The coating film can be formed, for example, at about 160 to 200 ° C. for about 20 to 40 minutes).

[0024]

EFFECT OF THE INVENTION Fluorine-containing unsaturated monomer (a), alkoxysilyl group-containing unsaturated monomer (b), hydroxyl group-containing unsaturated monomer (c), carboxyl group-containing unsaturated monomer (d), and other unsaturated monomers A coating line with high weather resistance and paint stability, for example, a mechanical share, by means of a matte anionic electrodeposition paint consisting of a vinyl copolymer resin (A) obtained by radical copolymerization with a crosslinking agent (B). In addition, they have found a paint that maintains a good finish and has a small amount of paint residue even in a low-speed turnover tank where the production amount is small and fresh paint is not supplied.

The reason for this is that the high weather resistance is largely due to the effect of the fluorine-containing monomer, but since the vinyl-based copolymer resin is one type as the base resin, the fluorine is oriented on the surface of the emulsion particles themselves. . The improvement of the paint stability means that the weather resistance is effectively improved when the coating film is formed. Only the vinyl copolymer resin (A) is used as the base resin.
It can be mentioned that the use of the kind maintained the water dispersibility of the aqueous emulsion even when the neutralizing agent such as the amine was lowered in the bath.

[0026]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to this. "Parts" and "%" mean "parts by weight" and "% by weight".

Vinyl copolymer resin No. Production Example 1 Into a reaction vessel, 80 g of isopropyl alcohol was charged and kept at 80 ° C., and the following monomers and 1 g of azobisisobutyronitrile were mixed. "Monomer combination" FAMAC (Note 1) 10 g KBM-503 (Note 2) 1 g 2-hydroxyethyl acrylate 12 g Acrylic acid 7 g Styrene 10 g Butyl acrylate 10 g Methyl methacrylate 30 g Ethyl acrylate 20 g Further hold at 80 ° C. for 1 hour to carry out the reaction. After adding 3 g of azobisisobutyronitrile, the solid content was adjusted with an organic solvent to obtain a vinyl copolymer resin No. 5 having a solid content of 55% by weight. 1 was produced. The vinyl copolymer resin No.
1 has an acid value of 55 mgKOH / g and a hydroxyl value of 58 mgKO
It was H / g and the weight average molecular weight was about 20,000. (Note 1) FAMAC: Nippon Mektron, product name, 2
-Perfluorooctyl methacrylate (Note 2) KBM-503: manufactured by Shin-Etsu Chemical Co., Ltd., trade name, γ-
Methacryloxypropyltrimethoxysilane.

Vinyl copolymer resin No. 2 to No. 4's
Production Example In the same manner as in Example 1, 80 g of isopropyl alcohol was charged into a reaction vessel and kept at 80 ° C., and the content of the monomer as shown in Table 1 and 1 g of azobisisobutyronitrile were added. Further, the mixture is kept at 80 ° C. for 1 hour to carry out the reaction, and after adding 3 g of azobisisobutyronitrile, the solid content is adjusted with an organic solvent to obtain a solid content of 55% by weight.
Vinyl copolymer resin No. 2 to No. Got 4.

[0029]

[Table 1] Vinyl copolymer resin No. Production Example 5 In a reaction vessel, 100 g of isopropyl alcohol and 150 g of n-butyl alcohol were charged and kept at 85 ° C., 75 g of butyl acrylate, 125 g of butyl methacrylate, 60 g of 2-ethylhexyl methacrylate,
2-hydroxyethyl methacrylate 115g, RUV
A-93 (trade name, UV absorber manufactured by Otsuka Chemical Co., Ltd.) 75
g, FA-711MM (manufactured by Hitachi Chemical Co., Ltd., trade name, 1,2,2,
Methacrylic acid ester containing 6,6-pentamethylpiperidyl group) 50 g, azobisdimethylvaleronitrile 5 g,
75 g of butyl cellosolve was added dropwise over 3 hours. Thirty
After aging for 5 minutes, azobis dimethyl valeronitrile 5
g, 40 g of butyl cellosolve were added dropwise over 30 minutes,
After further aging for 1 hour, the solid content was adjusted with an organic solvent and the vinyl copolymer resin No. 5 was produced. The copolymer has an acid value of 50 mgKOH / g, a hydroxyl value of 100 KOHmg / g, and a weight average molecular weight of about 20,000.
Met.

Example 1 55% of the vinyl copolymer resin No. 1 127.
0.4 for 3 g (solid content 70 g) of carboxyl groups
After blending an equivalent amount of triethylamine, then, Nikarac MX-600 (manufactured by Sanwa Chemical Co., Ltd., trade name,
Melamine resin) (30 g (solid content: 30 g)) was mixed and mixed to prepare an aqueous emulsion. While further stirring, the mixture was diluted with deionized water and gradually added dropwise so that the solid content became 10% by weight, and then adjusted with triethylamine so that the pH became 8.5.
o. 1 was produced. Using an anodized aluminum material (film thickness of about 10 μm, width 2 cm × 30 cm), anion electrodeposition paint No. 1 was electrodeposited to a film thickness of 10 μm, washed with water, and baked at 180 ° C. for 30 minutes to obtain a matte aluminum material No. Got 1.

Example 2 A matte aluminum material No. 1 was prepared in the same manner as in Example 1 except that the content of the formulation was as shown in Table 2. Got 2.

Comparative Examples 1 to 3 Matte aluminum material Nos. 1 and 2 were prepared in the same manner as in Example 1 except that the contents of the formulations in Table 2 were used. 3-5 were obtained.

[0033]

[Table 2]

Coating Method and Test Results Using the anion electrodeposition paints (clear) obtained in Examples and Comparative Examples as a bath, the object to be coated was subjected to secondary electrolytic treatment (degreasing-etching-neutralization-anodic conversion treatment). -Immerse anodized aluminum material (silver: size 150 x 70 x 0.5 mm) with a coating thickness of about 10 µm, which has been sealed, and electrodeposit the anionic electrodeposition coating (clear system) to 10 µm. After coating, washing with water and baking at 180 ° C. for 30 minutes.
Table 3 shows the test contents and test results.

[0035]

[Table 3]

(Note 3) Gloss: JIS K-5400
According to the 60 degree specular gloss of 7.6 (1990), the degree of gloss of the coating film is measured by measuring the reflectance when the incident angle and the light receiving angle are 60 degrees, respectively, and the gloss of the reference surface of the specular gloss is measured. 1
It is expressed as a percentage when 00 is set.

(Note 4) Paint stability: The paint was placed in an open container made of stainless steel, and the paint was stored in a motor equipped with a stirring blade for 30 minutes.
C. The residue after stirring for 14 days was examined. ∘ indicates that the residue is 5 mg / L or less, and is good. Δ indicates that the residue is 6 to 10 mg / L and is slightly poor.

(Note 5) Smoothness of coating film: coating surface (wrinkle skin,
The unevenness) was visually evaluated. Is good, △ is slightly bad, ×
Indicates a defect.

(Note 6) Accelerated weather resistance (gloss retention rate): A sunshine weatherometer (Suga Test Machine) was used.
Gloss retention = (Coating surface specular reflectance after 2000 hours /
Coating specular reflectance before test) x 100 Coating specular reflectance is J
IS K-5400 Measured by 60 degree specular reflectance (appearance): ◯: good without problems Δ: whitening is observed ×: cracks and whitening are seen on the entire coated surface

Continued front page    F term (reference) 4J038 CD071 CF051 CG141 CG161                       CG171 CG201 CH031 CH041                       CH081 CH121 CH171 CH251                       CJ031 CJ061 CJ091 CJ101                       CJ181 DA162 DB221 DG302                       DL121 GA03 GA06 GA12                       JB01 MA08 MA10 NA01 NA03                       NA25 PB05 PC02

Claims (3)

[Claims] 1. A fluorine-containing unsaturated monomer (a), an alkoxysilyl group-containing unsaturated monomer (b), a hydroxyl group-containing unsaturated monomer (c), a carboxyl group-containing unsaturated monomer (d), and other unsaturated monomers. A matte type anionic electrodeposition coating composition containing a vinyl copolymer resin (A) obtained by radically copolymerizing (e), and a crosslinking agent (B) having a functional group that reacts with a hydroxyl group. 2. The matte type anionic electrodeposition coating composition according to claim 1, wherein the fluorine-containing unsaturated monomer (a) is represented by the following formula (1). Formula (1) (In the formula, A is hydrogen or a methyl group, m is an integer of 0 to 4,
n represents an integer of 1 to 12) 3. The fluorine-containing unsaturated monomer (a) is 2
-The matte type anionic electrodeposition coating composition according to claim 1, which is perfluorooctyl methacrylate or trifluoroethyl methacrylate.